UNIVERSITY OF SCIENCE AND TECHNOLOGY BEIJING (China)
Inventor
Qiao, Mingliang
Zhang, Xiaoxue
Wang, Enmao
Wang, Lingyu
Wu, Huibin
Wang, Guanglei
Liu, Jinxu
Li, Hengkun
Chen, Linheng
Abstract
An FH40-HD50 high-ductility ship plate steel having a multiphase structure, and a preparation method therefor, belonging to the field of ship plate steel manufacturing. The chemical composition of the ship plate steel is as follows: C, Mn, Si, Ni, Nb, Alt, S, and P, the rest being Fe and unavoidable impurity elements; the FH40-HD50 high-ductility ship plate steel has a composition design with low-C-and-Nb microalloying as a core, and does not contain metal elements such as Cu, V, and Ti. The preparation method mainly comprises procedures such as smelting, continuous casting, hot rolling, and cooling; on-line optimization of a TMCP process involving three stages of cooling, i.e. "relaxation + ultrafast cooling + air cooling", enables control of a ferrite + pearlite + bainite multiphase structure, produces FH40-HD50 high-ductility ship plate steel having far higher plasticity and toughness than traditional high-strength ship plate steel, and improves the collision resistance of large ships without changing the structural design of the ships.
The present invention belongs to the field of alloy steel manufacturing. Disclosed are a 730 MPa-grade ultrahigh-strength steel plate for a high-rise building and a manufacturing method therefor. The steel plate comprises the following chemical components: C, Si, Mn, P, S, Cr, Ni, Cu, Nb, V, Ti and Al, with the balance being Fe and inevitable impurity elements. By means of utilizing low-C microalloying and the design of adding a small amount of Cr, Ni and Cu components, Nb, V and other microalloy elements are precipitated in a two-stage rolling process, so as to play a role in pinning austenite grains, and inhibiting the growth of the austenite grains, thereby refining the grain size. By means of a rolling process of strictly controlling the temperature and the compression ratio in the two-stage rolling process assisted by the method of a subsequent rapid-water-entry controlled cooling, by means of accurately controlling the red returning temperature, a certain ratio of a bainite and ferrite structure is obtained. The steel plate has good comprehensive performance of a low yield ratio, high strength, a high level of extension and high low-temperature toughness, and has important significance for the development of steel structure buildings.
A high-standard bearing hot-rolled ribbon steel and a manufacturing method therefor, relating to the technical field of steel production. The high-standard bearing hot-rolled ribbon steel comprises the following chemical components in percentage by mass: C: 0.95-1.06%; Si: 0.15-0.35%; Mn: 0.25-0.45%; Cr: 1.50-1.65%; Ni: 0.15-0.20%; Cu≤0.05%; Mo≤0.10%; Ti≤0.003%; As≤0.012%; Al≤0.05%; O≤0.0008%; Pb≤0.002%; P≤0.015%; S≤0.008%; and the balance being Fe and inevitable impurity elements. The obtained high-standard bearing hot-rolled ribbon steel has an inclusion rating result of coarse inclusions A+B+C+D≤1.0, fine inclusions A+B+C+D≤2.0, and carbide networks≤2.0, and meets the use requirements of high-end high-standard bearing hot-rolled ribbon steel manufacturers.
C21C 7/00 - Treating molten ferrous alloys, e.g. steel, not covered by groups
B21B 1/22 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling bands or sheets of indefinite length
4.
RARE EARTH-CONTAINING HIGH-STRENGTH WEAR-RESISTANT STEEL PLATE FOR EXTREMELY COLD REGION AND MANUFACTURING METHOD THEREFOR
A rare earth-containing high-strength wear-resistant steel plate for an extremely cold region and a manufacturing method therefor, relating to the technical field of steel production. The steel plate comprises the following chemical components, in mass percent: C: 0.20%-0.24%, Si: 0.20%-0.35%, Mn: 0.4%-0.8%, Nb: 0.035%-0.065%, V: 0.035%-0.065%, Ti: 0.001%-0.006%, Cr: 0.3%-1.0%, B: 0.0003%-0.0020%, Alt: 0.04%-0.07%, N≤0.0050%, H≤0.0002%, P≤0.015%, S≤0.0020%, Ce≥10 ppm, with the balance being Fe and inevitable impurities. The steel plate has impact energy KV2 of 64-75 J at -60°C, yield strength of 1,236-1,260 MPa, tensile strength of 1,464-1,498 MPa, elongation A50 of 14-17%, and surface hardness of 449-458 HB.
Disclosed in the present invention are an economical niobium-free 690 Pa-grade tempered high-strength steel plate and a manufacturing method. The present invention belongs to the technical field of steel production. The steel plate comprises the following chemical components: C, Si, Mn, P, S, Ti, V, Cr, Mo, Alt, B and the balance of Fe and impurities. The method comprises the following steps: a smelting process, a continuous casting process, a heating process, a rolling and tempering process, etc. The present invention provides an economical 690 MPa high-strength steel plate having good comprehensive performance and a production method therefor. Lath bainite and granular bainite are obtained, and the structure is uniform and fine; and the structure of the lath bainite and the granular bainite is beneficial for maintaining strength and good plasticity and toughness.
A method for producing a bridge steel plate with high efficiency and easy welding, relating to the technical field of steel production, the chemical composition and mass percentage of the steel plate are as follows: C: 0.05% to 0.15%, Si: 0.10% to 0.50%, Mn: 0.90% to 1.70%, P≤0.020%, S≤0.010%, Nb: 0.010% to 0.090%, V≤0.03%, Ti: 0.008% to 0.030%, Cr≤0.30%, Ni≤0.30%, Mo≤0.20%, Cu≤0.30%, B: 0.0005% to 0.0020%, Mg: 0.0008% to 0.0015%, Al: 0.015% to 0.030%, and the balance is Fe and unavoidable impurities. By adopting smelting and rolling processes, a structure type mainly composed of granular bainite + ferrite + pearlite/acicular ferrite + granular bainite is obtained, constituting a bridge steel that meets the requirements of high efficiency and easy welding performance.
Disclosed in the present invention is a preparation method for 52CrMoV4 spring steel for high-speed railway emu. The preparation method comprises the steps of electric furnace/converter smelting, LF refining, VD/RH vacuum treatment, heating, cogging, heating, material forming, annealing, straightening, peeling, polishing and flaw detection to achieve the quality control of the 52CrMoV4 spring steel. The present invention solves the quality control problem of 52CrMoV4 steel for high-speed railway springs, and all the indexes thereof satisfy technical requirements.
B21B 1/46 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
C21D 8/06 - Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
C21D 9/00 - Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor
C21D 9/52 - Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor for wiresHeat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor for strips
8.
CORROSION-RESISTANT L-SHAPED STEEL FOR LIQUID AMMONIA STORAGE TANKS AND METHOD FOR PREPARING SAME
22 of ≥68 J at -105 ℃, and an annual corrosion rate of 0.1-0.2 g/m2 in a liquid ammonia solution. The method for preparing same adopts a post-rolling slow cooling process, and thus features a simple process, high production efficiency, high cost-efficiency, safety, and reliability.
The present invention relates to the technical field of steel production. Disclosed are high-strength bridge steel and a manufacturing method therefor. The chemical components, in percentage by mass, of the high-strength bridge steel are as follows: C: 0.04%-0.09%; Si: 0.10%-0.40%; Mn: 1.00%-1.40%; P≤0.015%; S≤0.003%; Nb: 0.010%-0.030%; V: 0.010%-0.030%; Ti: 0.008%-0.030%; Cr: 0.30%-0.50%; Ni: 0.30%-0.50%; Cu: 0.10%-0.30%; B: 0.0005%-0.0020%; Mg: 0.0008%-0.0015%; Al: 0.015%-0.030%; the remainder being Fe and inevitable impurities. An element Mo is replaced with a boron element; a method for using an Nb-Ti-B composite alloy is researched; the hardenability of a steel plate is improved by means of the precipitation hardening effect; the alloy design costs are reduced; the market competitiveness is improved.
Disclosed in the present invention are a low-cost bridge steel and a manufacturing method thereof, relating to the technical field of steel production. The chemical composition and mass percentage thereof are as follows: C: 0.10% to 0.16%, Si: 0.15% to 0.35%, Mn: 1.20% to 1.60%, P≤0.018%, S≤0.005%, Nb: 0.020% to 0.040%, V: 0.020% to 0.050%, Ti: 0.008% to 0.030%, Cr≤0.05%, Ni≤0.05%, Mo≤0.05%, Cu≤0.05%, B: 0.0005% to 0.0020%, Mg: 0.0008% to 0.0015%, Al: 0.015% to 0.030%, and the balance is Fe and unavoidable impurities. The Nb-Ti-B composite alloy technology is adopted to form a niobium carbonitride compound, trace boron is used for solid solution pinning of the grain boundary, a small amount of BN is separated out, generation of ferrite is promoted, the product strength and toughness are improved, the use amount of precious elements such as Cr, Ni, Mo, and Cu is reduced, and the alloy design cost is reduced.
A 390 MPa-grade steel plate for high-rise infrastructure and a production method therefor, relating to the technical field of steel production. The steel plate comprises the following chemical components in percentage by mass: C: 0.15%-0.18%, Si: 0.25%-0.35%, Mn: 1.40%-1.55%, Nb: 0.032%-0.042%, Ti: 0.010%-0.020%, V: 0.045%-0.055%, N: ≤0.0080%, P: ≤0.015%, S: ≤0.005%, and the balance of Fe and inevitable impurities. On the basis of an original V and N system, a small amount of Nb alloy is creatively added for production, so that the performance of the produced steel plate completely meets usage requirements of 390 MPa-grade steel for high-rise infrastructure having a thickness of 50-60 mm under GB/T 19879-2015, thereby greatly reducing the production cost and the customer purchasing cost.
The present invention relates to the technical field of steel production. Disclosed are a low-temperature structural steel for TMCP-state low-cost high heat input welding and a manufacturing method. By means of a low-carbon niobium-free component design and a smelting process based on oxide metallurgy technology, the present invention forms fine, dispersed and compound oxide particles in steel, uses the high-temperature thermally-stable fine and dispersed inclusion particles to pin austenite grain boundaries of a heat affected zone in welding under a high heat input condition, so as to refine austenite grains, and uses the oxides as nucleation points of intragranular acicular ferrite (IAF) to form in the heat affected zone in welding IAF tissues having good strength and ductility, thus further remarkably improving the ductility of the heat affected zone in high heat input welding. Producing high-strength shipbuilding steel plates by means of TMCP technology combined with high-temperature low-speed heavy reduction rolling does not require heat treatment, reduces costs, and involves stable production processes.
The present invention relates to an ultra-wide quenched and tempered abrasion-resistant steel plate and a manufacturing method therefor. The chemical components of the steel plate are as follows: C: 0.13%-0.25%, Si: 0.30%-0.60%, Mn: 0.5% -1.5%, P≤0.020%, S≤0.0020%, Cr: 0.30%-0.60%, Mo≤0.30%, Ni: ≤0.30%, Ti: 0.008%-0.025%, Nb≤0.025%, V≤0.030%, B: 0.0015%-0.0025%, Alt: 0.025%-0.07%, N≤0.0050%, H≤0.0003%, Ceq≤0.65, and the balance of Fe and unavoidable impurities. Processes of the steel plate manufacturing method are stable and easy to execute, and a final steel plate exhibits good width directional performance uniformity, has a good welding property and low-temperature impact toughness, and can be welded without preheating.
C21D 8/02 - Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
C21D 1/18 - HardeningQuenching with or without subsequent tempering
C21D 11/00 - Process control or regulation for heat treatments
B21B 1/46 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
B21B 1/22 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling bands or sheets of indefinite length
15.
HIGH-STRENGTH CORROSION-RESISTANT CRUDE OIL STORAGE TANK STEEL PLATE FOR HIGH HEAT INPUT WELDING AND MANUFACTURING METHOD THEREFOR
The present invention relates to the technical field of steel production. Disclosed in the present invention are a high-strength corrosion-resistant crude oil storage tank steel plate for high heat input welding and a manufacturing method therefor. The high-strength corrosion-resistant crude oil storage tank steel plate comprises the following chemical components in percentages by mass: C: 0.07%-0.12%, Si: 0.25%-0.45%, Mn: 1.40%-2.0%, P≤0.012%, S≤0.005%, Cu: 0.1%-0.4%, Ni: 0.1%-0.5%, Mo: 0.10%-0.30%, V: 0.01%-0.05%, Ti: 0.005%-0.035%, B: 0.0005%-0.0035%, Sn: 0.01%-0.06%, La: 0.001%-0.03%, Ca: 0.0002%-0.005%, Zr: 0.001%-0.02%, O≤0.0030%, N: 0.0045%-0.0065%, and the balance of Fe and inevitable impurities. Under the welding heat input of 50-100 KJ/cm, good welding performance is achieved; moreover, the average annual corrosion rate C.R.ave is smaller than or equal to 1.0 mm/a in a corrosion environment for a wallboard of a crude oil storage tank, such that the requirement of the crude oil storage tank for long-term crude oil storage is met.
Disclosed in the present disclosure is a stainless steel composite plate for a weathering steel bridge having a low yield ratio, comprising a base material and a covering material which satisfy that an atmospheric corrosion resistance index I is greater than or equal to 6.0, the total thickness being 5-60 mm, and the thickness of the covering material being 0.5-5.0 mm.
Disclosed in the present invention are a 345 MPa-grade steel plate for a marine-atmosphere corrosion-resistant structure, and a preparation method therefor. The present invention belongs to the technical field of steel production. The chemical components of the steel plate comprise: C, Si, Mn, P, S, Nb, Ti, V, Cu, N, Mo, Alt and the balance of Fe and inevitable inclusions. The steps of the preparation method comprise: smelting, continuous casting, soaking, rolling, relaxation, cooling and off-line tempering. By means of a scientific component design and a matched manufacturing method of controlled rolling, controlled cooling and tempering in the present invention, a 345 MPa-grade weather-proof bridge steel with a low yield ratio, high toughness and high ductility is obtained. The yield strength thereof is 400 MPa or above, the tensile strength is 530 MPa or above, the yield ratio is smaller than or equal to 0.80, the -60ºC Akv is 230 J or above, the elongation is larger than or equal to 24%, the corrosion-resistant alloy index V is larger than or equal to 1.20, and the steel has good comprehensive performance and is suitable for steel structure application.
Disclosed in the present invention is a method for producing a 1000 MPa-grade hydroelectric steel plate having a thickness greater than 100mm, belonging to the field of metallurgy. The method comprises a steel making process, a billet heating process, a rolling process and a heat treatment process. The present invention, by means of composition designs such as peritectic steel, Ni+Cr+Mo alloying, and Nb+V+Ti microalloying, rolls a continuous casting billet having a thickness of 370mm or above at an increased rolling reduction ratio, uses a differential temperature rolling technique during the rolling process so as to improve the seepage deformation in a rolling thickness direction, and finally, after subjecting a steel plate to quenching heat treatment and tempering heat treatment, obtains a 1000 MPa-grade hydroelectric steel plate having a thickness greater than 100mm, achieving properties of the yield strength being ≥890 MPa, the tensile strength being 930-1130MPa, and the transverse low-temperature impact energy of the steel plate at -40℃ being ≥120J. Due to a weld cold cracking susceptibility coefficient Pcm being≤0.28%, the steel plate has a good welding property, and meets the welding quality and efficiency requirements of hydroelectric engineering project construction sites.
B21B 1/22 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling bands or sheets of indefinite length
C21D 8/02 - Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
C21D 1/18 - HardeningQuenching with or without subsequent tempering
C22C 38/44 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
C22C 38/46 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
C22C 38/50 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
C22C 38/48 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
C22C 38/54 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
C22C 38/02 - Ferrous alloys, e.g. steel alloys containing silicon
C22C 38/04 - Ferrous alloys, e.g. steel alloys containing manganese
B21B 3/00 - Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences
B21B 1/46 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
B21B 37/74 - Temperature control, e.g. by cooling or heating the rolls or the product
19.
MANUFACTURING METHOD FOR 800 MPA-GRADE HIGH-STRENGTH STEEL PLATE FOR STRESS-CORROSION-RESISTANT SPHERICAL TANK
An 800 MPa-grade high-strength steel plate for a stress-corrosion-resistant spherical tank, and a manufacturing method therefor. The present invention belongs to the field of metallurgy, and the method comprises a steelmaking step, a blank heating step, a rolling step, a cooling step and a heat treatment step. The high-strength steel for the stress-corrosion-resistant spherical tank is developed by using a low-carbon (less than or equal to 0.12%), low-manganese and high-Cr component design, improving the hardenability of the steel with a proper amount of Mo, improving the low-temperature toughness with a proper amount of Ni, and using controlled rolling, quenching and tempering techniques, etc. The steel plate has a maximum thickness of 80 mm, a yield strength larger than or equal to 690 MPa, a tensile strength of 780-940 MPa, a elongation after fracture larger than or equal to 15%, a -40°C low-temperature impact energy larger than or equal to 100 J, and a -40°C low-temperature impact energy after SR postweld heat treatment greater than or equal to 80 J. According to the NACE 0177-2005 standard, a sample is tested under the load of 80% nominal yield strength by means of a method A, the steel plate does not crack after being subjected to a hydrogen sulfide stress corrosion resistant test for 720 hours, and the construction requirements of a large stress-corrosion-resistant spherical tank are satisfied.
A high-strength corrosion-resistant crude oil storage tank steel plate for high heat input welding, and a manufacturing method. The steel plate comprises the following components in percentage by weight: C: 0.07-0.12, Si: 0.25-0.45, Mn: 1.40-2.0, P≤0.012, S≤0.005, Cu: 0.1-0.4, Ni: 0.1-0.5, Mo: 0.10-0.30, V: 0.01-0.05, Ti: 0.005-0.035, B: 0.0005-0.0035, Sn: 0.01-0.06, La: 0.001-0.03, Ca: 0.0002-0.005, Zr: 0.001-0.02, O≤0.0030, N: 0.0045-0.0065, and the remainder being Fe and inevitable impurities. The crude oil storage tank steel plate has good mechanical properties, welding properties, and corrosion resistance, and meets the conditions that the transverse impact energy mean value at -20°C is greater than or equal to 80 J, the yield strength is greater than or equal to 490 Mpa, the tensile strength is 610-730 MPa, A is greater than or equal to 17%, the impact energy mean value of a welding heat affected zone is greater than or equal to 47 J, and the average annual corrosion rate is less than or equal to 1.0 mm/a.
A micro-molybdenum-type weathering bridge steel plate disclosed by the present invention is characterized in that the steel plate is smelted from the following components by weight: C: 0.05-0.08%, Si: 0.30-0.50%, Mn: 1.25-1.35%, P: 0.010-0.014%, S≤0.003%, Nb: 0.020-0.030%, Ti: 0.010-0.020%, V: 0.040-0.050%, Cu: 0.25-0.40%, Ni: 0.25-0.35%, Cr: 0.45-0.55%, Mo: 0.03-0.08%, Alt: 0.020-0.040%, and the balance from Fe and impurities. Less content of molybdenum reduces the production cost of the steel plate, the yield strength of the steel plate is 500-600 MPa, the yield strength ratio is ≤0.85, and the maximum thickness of the steel plate can reach 80 mm.
Disclosed in the present invention are steel for forged bucket teeth of an excavator, and a preparation method therefor. The steel for forged bucket teeth of an excavator comprises the following chemical components in percentages by mass: 0.30-0.37% of C, 1.25-1.55% of Si, 1.00-1.30% of Mn, less than or equal to 0.035% of P, less than or equal to 0.035% of S, 1.20-1.50% of Cr, 0.020-0.050% of Al and the balance of Fe and inevitable impurities. The preparation process therefor comprises converter smelting, LF refining, RH vacuum treatment, continuous casting, heating, rolling and cooling. Low-cost alloy elements are used in the present invention for component design, and the optimal component proportion is used, so as to obtain the steel for forged bucket teeth with a yield strength larger than or equal to 1500 MPa, a tensile strength larger than or equal to 1800 MPa, a 20°C longitudinal impact absorbing energy larger than or equal to 45 J, a rolling-state hardness of 220-240 HB and good hardenability.
Provided are 290 Mpa-grade low-yield-strength steel used in a low-temperature harsh environment, and a manufacturing method therefor, relating to the technical field of steel manufacturing. The low-yield-strength steel comprises the following components in percentage by weight: 0.06%≤C≤0.12%, 0.1%≤Si≤0.3%, 0.9%≤Mn≤1.2%, P≤0.026%, S≤0.016%, 0.01%≤Al≤0.06%, and the remainder being Fe and inevitable impurities. The specific steps are: (1) a heating process; (2) a hot rolling process; and (3) a cooling process. A low-yield-strength steel plate can be obtained by low-cost component design, two-stage controlled rolling, and a cooling process, wherein the thickness is less than or equal to 100 mm, the yield strength is 270-310 MPa, the impact at -60°C is larger than or equal to 200 J, and the matrix structure is blocky ferrite plus pearlite.
Disclosed in the present invention is a method for preparing steel 50CrVA for a transmission chain of an engine, the method comprising the procedures of electric furnace smelting, LF refining, a VD vacuum treatment, continuous casting, heating, rolling, cooling and coiling. In the present invention, a deoxidizing furnace-protecting agent is added at the end point of the electric furnace smelting for deoxidation to guarantee that the oxygen content of molten steel is 400 ppm or less during tapping, such that the inclusion content is reduced; and at the end, the contents of the initial components of the molten steel reach 70-90% of the lower limits of the contents of target components; during the LF refining, the molten steel is alloyed by using ferrosilicomanganese, a high-carbon ferrochrome, a ferrovanadium alloy and a high-purity graphite carbon material, and is deoxidized by using a high-purity graphite carbon material and a high-purity silicon carbide; and in the continuous casting procedure, the continuous casting of a small square billet and a small rectangular billet is used, and constant-pulling-speed casting is carried out by using a five-machine five-strand small square billet continuous casting machine, thereby improving the purity of a cast steel billet. The inclusion content of the finished product prepared in the present invention is as low as grade 0.5 or below, the fluctuation of chemical components is small, and the performance of different batches of materials is stable; a finished steel strip product has less surface decarburization, a fine and uniform structure, a grain size of grade 7.0 and a good toughness; and an engine transmission chain processed therefrom has a long service life.
The present invention discloses a bar for a motor shaft of a new energy vehicle and a preparation method therefor, and relates to the technical field of steel production. The bar comprises the following chemical components, in percentages by mass: C: 0.14-0.21%, Si≤0.40%, Mn: 1.00-1.40%, P≤0.025%, S: 0.010-0.035%, Cr: 0.80-1.20%, Mo: 0.10-0.20%, Al: 0.020-0.050%, and H≤0.00015%, with the balance being Fe and inevitable impurities. This type of steel can fully meet the requirements of an electric vehicle having a high rotating speed and a high torque for stable driving.
B22D 11/18 - Controlling or regulating processes or operations for pouring
C21D 8/06 - Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
B21B 1/16 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling wire or material of like small cross-section
B21B 37/74 - Temperature control, e.g. by cooling or heating the rolls or the product
26.
LOW-YIELD-RATIO WEATHER-RESISTANT BRIDGE STEEL AND MANUFACTURING METHOD
A low-yield-ratio weather-resistant bridge steel and a manufacturing method, relating to the technical field of steel production. The chemical components of the bridge steel are as follows, in percentage by mass: 0.06%-0.09% of C, 0.15%-0.30% of Si, 1.51%-1.65% of Mn, 0.009%-0.015% of P, ≤0.002% of S, 0.020%-0.050% of Nb, 0.010%-0.020% of Ti, 0.010%-0.030% of V, 0.30%-0.40% of Cu, 0.30%-0.45% of Ni, 0.45%-0.60% of Cr, 0.16%-0.25% of Mo, 0.02%-0.04% of Alt, and the balance being Fe and inevitable impurities. By means of scientific design on components and the matched manufacturing method of controlled rolling, controlled cooling and tempering, the weather-resistant bridge steel has the characteristics of low yield ratio, high low-temperature toughness and high ductility.
C21D 8/02 - Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
B21B 37/74 - Temperature control, e.g. by cooling or heating the rolls or the product
B21B 1/46 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
27.
ULTRAFINE GRAIN STEEL PLATE AND PREPARATION METHOD THEREFOR
333 in a heating furnace, and preserving the temperature for 30±10 min; S4, when the temperature of the discharged reheated intermediate blank reaches 760±10ºC, subjecting same to second-stage finish rolling, wherein the accumulated reduction rate of the core part is 40-50%; and S5, after the second-stage finish rolling is finished, subjecting same to controlled cooling and stack cooling, so as to obtain an ultrafine grain steel plate. The ultrafine grain steel plate has a thickness of 40-60 mm, a yield strength larger than 460 MPa and good low-temperature toughness, and reaches a -101ºC impact energy larger than 120 J.
A series of high-grade grade E steels used for weather-resistant bridges, and a single-billet, multi-grade production method therefor. The composition of the steel material in percentages by weight comprises: C: 0.05-0.07%, Si: 0.25-0.45%, Mn: 1.25-1.50%, P: 0.009-0.014%, S: ≤0.003%, Nb: 0.02-0.03%, Ti: 0.008-0.018%, Cu: 0.25-0.35%, Ni: 0.25-0.35%, Cr: 0.45-0.55%, Mo: 0.05-0.15%, Alt: 0.020-0.045%, and the remainder is Fe and impurities. The production method therefor comprises steps such as billet heating, first stage rolling, second stage rolling and heat treatment. A set of component designs is used to realize single-billet, multi-grade assembly production, which is beneficial for saving time and simplifying a production process.
C22C 38/02 - Ferrous alloys, e.g. steel alloys containing silicon
C22C 38/04 - Ferrous alloys, e.g. steel alloys containing manganese
C21D 8/02 - Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
B21B 37/74 - Temperature control, e.g. by cooling or heating the rolls or the product
29.
120KSI-STEEL-GRADE HIGH-STRENGTH HIGH-TOUGHNESS HIGH-HYDROGEN SULFIDE-RESISTANCE HOT-ROLLED STEEL ROUND BAR USED FOR DRILL PIPE JOINT, AND PREPARATION METHOD THEREFOR
Disclosed in the present invention are a 120ksi-steel-grade high-strength high-toughness high-hydrogen sulfide-resistance hot-rolled steel round bar used for a drill pipe joint, and a preparation method therefor. The chemical components of said steel comprise, by mass, 0.20-0.30% of C, 0.15-0.35% of Si, 0.45-0.75% of Mn, 1.10-1.50% of Cr, 0.60-0.80% of Mo, 0.020-0.060% of Nb, ≤0.008% of P, and ≤0.003% of S, with the balance being Fe and inevitable impurities. The preparation method comprises: electric furnace, LF refining, vacuum degassing (VD), high-precision continuous casting, steel billet inspection, heating furnace temperature controlled heating, rough rolling, horizontal and vertical alternating high-precision continuous rolling, collection on a cooling bed, and finished product inspection. The hot-rolled steel round bar for a drill pipe joint has high strength, high toughness and strong hydrogen sulfide stress corrosion resistance and can be used for development of acidic oil and gas fields.
C22C 38/02 - Ferrous alloys, e.g. steel alloys containing silicon
C22C 38/26 - Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
B21B 1/02 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling heavy work, e.g. ingots, slabs, billets, in which the cross-sectional form is unimportant
C22C 38/38 - Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
C22C 38/04 - Ferrous alloys, e.g. steel alloys containing manganese
30.
360HB-450HB GRADE ABRASION RESISTANT STEEL AND PRODUCTION METHOD THEREFOR
Disclosed in the present invention is a 360HB-450HB grade abrasion resistant steel, comprising the following chemical components in percentage by mass: C: 0.10%-0.30%, Si: 0.20%-0.50%, Mn: 0.80%-1.60%, P≤0.020%, S≤0.005%, Ti: 0.008%-0.025%, Cr: 0.20%-1.00%, Ni≤0.60%, Mo: 0.10%-0.50%, Al: 0.025%-0.055%, B: 0.0010%-0.0030%, Mg: 0.0010%-0.0018%, N≤0.0045%, and the remainder being Fe and inevitable impurities, the Brinell hardness of the steel grade surface being 330-480 HBW. Further disclosed is a production method for the abrasion resistant steel. The present invention formulates components of the abrasion resistant steel with the steel grade of NM360-NM450 according to the national standard "GB/T 24186-2009 high strength abrasion resistant steel plates for construction machine", and the abrasion resistant steel performance index satisfying the national standard requirement is obtained.
C21D 9/00 - Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor
B21B 1/46 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
31.
500 HB GRADE OR ABOVE ABRASION-RESISTANT STEEL AND PRODUCTION METHOD THEREFOR
Disclosed in the present invention is 500 HB grade or above abrasion-resistant steel, the chemical components and the mass percentages thereof are as follows: 0.15%-0.45% of C, 0.15%-0.50% of Si, 0.50%-1.80% of Mn, P ≤ 0.015%, S ≤ 0.003%, V ≤ 0.030%, Nb ≤ 0.050%, 0.008%-0.025% of Ti, 0.50%-1.50% of Cr, Ni ≤ 1.00%, 0.20%-0.80% of Mo, 0.025%-0.055% of Al, 0.0010%-0.0050% of B, 0.0010%-0.0018% of Mg, N ≤ 0.0045%, and the balance being Fe and inevitable impurities. The steel grade surface Brinell hardness is greater than or equal to 470 HBW. Further disclosed is a production method for the abrasion-resistant steel. The present invention formulates the components of NM500-NM600 steel grade abrasion-resistant steel according to a national standard "GB/T24186-2009 High Strength Abrasion Resistant Steel Plates for Construction Machine", thereby obtaining the abrasion-resistant steel performance indices meeting the national standard requirement.
An ultra-low-temperature steel, and a heat treatment process therefor and the use thereof. The ultra-low-temperature steel comprises the following components: C: 0.41-0.45%, Mn: 23.5-24.5%, Cr: 3.5-3.7%, Cu: 0.35-0.45%, Ni: 0.55-0.65%, V: 0.20-0.24%, Mo: 0.20-0.24%, Si: 0.15-0.25%, and Al: 0.02-0.04%, with the balance being Fe and inevitable impurity elements. The ultra-low-temperature steel has a fully-austenitic structure, and has stacking fault energy at -269ºC of 18-21 mJ·m-2. By means of cooperation between a specific heat treatment process and specific components, the ultra-low-temperature steel has multiple properties of good ultra-low-temperature resistance, corrosion resistance and hydrogen damage resistance, can be applied to the storage and transportation of ultra-low-temperature media such as liquefied natural gas and liquid hydrogen, and is suitable for complex environments such as land, ocean and aviation.
Disclosed in the present invention is a manufacturing method for a hot forging-formed, composite-quenched and structure-refined high-strength bolt. The manufacturing method comprises hot forging forming and complete quenching, critical zone quenching, tempering, thread rolling, surface phosphorization and a blackening treatment, and specifically comprises: firstly, induction heating a bolt steel bar to 920-1000ºC, carrying out heat preservation followed by hot forging forming, and controlling the final forging temperature to be 830-850ºC; immediately quenching the bolt by using residual heat after forging, and then cooling the bolt; after the bolt is cooled to room temperature, re-heating the bolt to 760-790ºC, carrying out heat preservation followed by oil quenching and cooling; then heating the bolt to 350-500ºC for tempering treatment, and carrying out heat preservation and air cooling on the bolt; and finally, carrying out a post-treatment step. The bolt prepared by means of the preparation method of the present invention has a high strength and a high toughness, wherein the obtained bolt has a tensile strength of larger than or equal to 1100 MPa, an elongation after fracture of larger than or equal to 12%, a reduction of area of larger than or equal to 60%, and a -20ºC ballistic work of larger than or equal to 85 J.
A flux-cored gas shielded welding wire for 9% Ni steel used for storage tanks, which wire comprises 62-68% of a steel strip, and 32-38% of a flux powder, wherein the steel strip comprises the following chemical components: 0.016-0.031% of C, 0.51-0.70% of Si, 0.29-0.57% of Mn, 3.15-5.03% of Cr, 10.15-12.03% of Ni, ≤0.002% of P, and ≤0.001% of S, with the balance being Fe and inevitable impurities; and the flux powder comprises the following chemical components: 18-26% of rutile, 3-5% of zircon sand, 3-5% of potassium titanate, 2-4% of electrolytic manganese, 56.08-60.41% of a nickel powder, 10.40-12.68% of a molybdenum powder, 0.01-0.02% of a cobalt powder, 0.02-0.04% of an aluminum powder, and 22.62-24.64% of high-carbon ferrochrome, with the balance being an iron powder. The welding wire has a higher deposition rate and higher welding efficiency. The present invention further relates to a preparation method for a flux-cored gas shielded welding wire for 9% Ni steel used for storage tanks, and a use method for same.
The present invention discloses 7Ni steel and a production method therefor, and relates to the technical field of steel production. The steel comprises the following chemical components in percentages by mass: C: 0.030-0.060%, Si: 0.05-0.30%, Mn: 0.70-1.0%, P≤0.005%, S≤0.002%, residual Nb≤0.0050%, residual V≤0.003%, residual Ti≤0.005%, Ni: 6.50-7.50%, Cr≤0.05%, Mo: 0.20-0.30%, Cu≤0.05%, Al: 0.020-0.050%, Mg: 0.0008-0.0020%, N≤0.0060%, H≤0.0002%, and the balance of Fe and inevitable impurities. By means of a series of process improvements on smelting, rolling, heat treatment, etc., the process problem of intergranular cracks of the steel grade is solved, the advantages of batch smelting and manufacturing of the steel grade are obtained, the manufacturing stability is greatly improved, and the manufacturing cost is greatly reduced.
The present invention discloses 09MnNiDR steel and a production method therefor, and relates to the technical field of steel production. The steel comprises the following chemical components in percentages by mass: C: 0.050-0.15%, Si: 0.10-0.30%, Mn: 1.0-1.60%, P≤0.013%, S≤0.005%, Nb: 0.010-0.030%, Ni: 0.40-0.60%, Al: 0.020-0.050%, N≤0.0060%, H≤0.0002%, Mg: 0.0008-0.0020%, and the balance of Fe and inevitable impurities. By means of a series of process improvements on smelting, rolling, heat treatment, etc., the process problem of intergranular cracks of the steel grade is solved, the advantages of batch smelting and manufacturing of the steel grade are obtained, the manufacturing stability is greatly improved, and the manufacturing cost is greatly reduced.
The present invention discloses 9Ni steel and a production method therefor, and relates to the technical field of steel production. The steel comprises the following chemical components in percentages by mass: C: 0.030-0.060%, Si: 0.10-0.30%, Mn: 0.50-0.80%, P≤0.005%, S≤0.002%, residual Nb≤0.0050%, residual V≤0.003%, residual Ti≤0.005%, Ni: 8.50-9.50%, Cr≤0.05%, Mo≤0.05%, Cu≤0.050%, Al: 0.020-0.050%, B≤0.0005%, Mg: 0.0008-0.0020%, N≤0.0060%, H≤0.0002%, and the balance of Fe and inevitable impurities. By means of a series of process improvements on smelting, rolling, heat treatment, etc., the process problem of intergranular cracks of the steel grade is solved, the advantages of batch smelting and manufacturing of the steel grade are obtained, the manufacturing stability is greatly improved, and the manufacturing cost is greatly reduced.
Disclosed in the present invention is a preparation method for a high-strength and high-toughness spring steel wire rod. The preparation method comprises performing the following steps in sequence: converter smelting, LF refining, continuous casting, hot charging and hot delivery, heating, controlled rolling, spinning and controlled cooling, wherein during blank heating, residual oxygen is controlled to be 3-6%, the air-fuel ratio is controlled to be 1.1-1.5, the heating temperature of a high-temperature section is 1150-1220ºC, and the heating time of the high-temperature section is 120-180 min. The spring steel wire rod has a good strength and a good toughness; the tensile strength is greater than or equal to 1900 MPa, the percentage elongation after fracture is greater than or equal to 10%, and the percentage reduction of area is greater than or equal to 45%; and the spring steel wire rod is suitable for the design and selection of materials for commercial vehicle brake springs and automobile suspension springs.
C22C 38/02 - Ferrous alloys, e.g. steel alloys containing silicon
C22C 38/20 - Ferrous alloys, e.g. steel alloys containing chromium with copper
C22C 38/22 - Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
C22C 38/24 - Ferrous alloys, e.g. steel alloys containing chromium with vanadium
C22C 38/28 - Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
C22C 38/38 - Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
C22C 38/42 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
C22C 38/44 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
C22C 38/46 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
C22C 38/50 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
C22C 38/58 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
B21B 1/46 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
39.
STEEL FOR THIN-GAUGE BRIDGES AND PRODUCTION METHOD THEREFOR
The present invention relates to the technical field of steel production. Disclosed is a steel for thin-gauge bridges and a production method therefor. The chemical composition and mass percentage of said steel are as follows: C≤0.20%, Si≤0.55%, Mn≤2.00%, P≤0.020%, S≤0.010%, Nb≤0.060%, V≤0.080%, Ti: 0.006%-0.020%, Cr≤0.80%, Ni≤1.10%, Mo≤0.60%, Cu≤0.55%, Al: 0.015%-0.060%, Mg: 0.0008%-0.0020%, B≤0.0040%, N≤0.0120%; Ca is not added, and the balance is Fe and unavoidable impurities. By means of an advanced magnesium metallurgy technology, the welding performance of products is effectively improved. An advanced composite rolling technology is employed to effectively improve the surface quality of thin-gauge products; at the same time, the machine-hour output of the product is greatly improved.
C22C 38/02 - Ferrous alloys, e.g. steel alloys containing silicon
C22C 38/04 - Ferrous alloys, e.g. steel alloys containing manganese
C22C 38/06 - Ferrous alloys, e.g. steel alloys containing aluminium
C22C 38/42 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
C22C 38/44 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
C22C 38/46 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
C22C 38/48 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
C22C 38/50 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
C22C 38/54 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
B21B 1/38 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling sheets of limited length, e.g. folded sheets, superimposed sheets
B23P 15/00 - Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
C22C 33/06 - Making ferrous alloys by melting using master alloys
40.
METHOD FOR CONTROLLING SURFACE QUALITY OF NICKEL-BASED STEEL PLATE
A method for controlling the surface quality of a nickel-based steel plate, comprising the following chemical components and the percentages by mass: C: 0.03%-0.07%; Si: 0.10%-0.30%; Mn: 0.60%-0.90%; P: ≤0.005%; S: ≤0.002%; Nb: ≤0.020%; V: ≤0.010%; Ti: ≤0.030%; Cr: ≤0.30%; Mo: ≤0.30%; Ni: 0.50%-9.50%; Cu: ≤0.05%; Al: 0.020%-0.050%; N: ≤0.0045%; H: ≤0.0002%; and the balance being Fe and inevitable impurities. By optimization of a smelting process, the surface treatment of a casting blank and the refining of a heating furnace process, the surface quality of a steel plate is improved.
B05D 7/14 - Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
B23P 15/00 - Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
41.
HIGH WEAR RESISTANCE STEEL FOR COAL MINING AND PRODUCTION METHOD THEREFOR
A high wear resistance steel for coal mining and a production method therefor. Chemical components and mass percentages are as follows: C: 0.15-0.30 %, Si: 0.20-0.50 %, Mn: 0.90-1.40 %, P ≤ 0.015 %, S ≤ 0.0020 %, Nb: ≤ 0.030 %, V: ≤ 0.020 %, Ti: 0.008-0.015 %, Cr: 0.30-0.90 %, Ni ≤ 0.60 %, Mo: 0.20-0.50 %, Al: 0.025-0.050 %, B: 0.0010-0.0020 %, Mg: 0.0010-0.0018 %, N ≤ 0.0045%, H ≤ 0.0002%, and the balance being Fe and unavoidable impurities. The steel grade of a product is 360-500 HBW, and the thickness specification is 3-180 mm. By means of micro-alloying dispersed particles of a magnesium metallurgy technique, the wear resistance of the product is improved.
The present invention relates to the technical field of steel production. Disclosed are a wear-resistant steel and a production method therefor. The wear-resistant steel comprises the following chemical components in percentage by mass: C: 0.10％-0.45％; Si: 0.20％-0.55％; Mn: 0.50％-1.50％; P≤0.015％; S≤0.003％; Nb≤0.060％; V≤0.030％; Ti: 0.008％-0.025％; Cr: 0.20％-1.00％; Ni≤1.80％; Mo≤0.50％; Al: 0.025％-0.055％; B: 0.0010％-0.0030％; Mg: 0.0010％-0.0018％; N≤0.0045％; and the balance of Fe and inevitable impurities. On the premise that a high-strength martensite structure of a wear-resistant steel plate is ensured, micro-alloying elements is quantified, thereby reducing the quantity and the size of carbonitrides; and the cooling speed and austenite temperature of a casting blank are regulated and controlled, and a secondary quenching optimization process is used, thereby refining structure grains, eliminating the structure stress, and avoiding the occurrence of delayed cracks in the wear-resistant steel during a cutting and grinding process of the casting blank and the steel plate.
A method for producing a thin specification steel plate, wherein a rolling process comprises: turning off a roller-table cooling water, smoke suppression and a rolling mill side spraying, two pieces of steel in advance; closing a roller guard plate cleaning water hand valve by means of Wuye; and then after an interval of 30 minutes, turning on a steel-rotating-roller-table cooling water for cooling for 1-2 minutes. When a 6 mm steel plate is produced, rough descaling is carried out for one pass, a rolling mill is not descaled, and when steel plates with other thicknesses are produced, the rolling mill is descaled for the first pass; a tapping temperature PDI is set to be 1250 °C; a steel rotating code is 3, and 10+1 rolling passes and 2 forming passes are provided, and the rolling speed is set to be 5.5-5.6 m/s; a wedge-shaped rolling is adjusted to have a shape with small arcs at the head and the tail, and the roller shifting limit value of the last three passes of finishing rolling is manually set according to the on-site plate shape condition.
B21B 1/38 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling sheets of limited length, e.g. folded sheets, superimposed sheets
B21B 15/00 - Arrangements for performing additional metal-working operations specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
B21B 37/74 - Temperature control, e.g. by cooling or heating the rolls or the product
B21B 43/00 - Cooling beds, whether stationary or movingMeans specially associated with cooling beds, e.g. for braking work or for transferring it to or from the bed
B21B 45/08 - Devices for surface treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling hydraulically
A high-strength nano heat insulation plate and a preparation method therefor. The nano heat insulation plate comprises, in percentages by weight: 43-75% of a heat insulating filler, 7-15% of an opacifier, 10-20% of a binder, 2-6% of a reinforcing fiber, 0.5-2% of a plasticizer, 1-5% of a performance additive, and 3-10% of water. The nano heat insulation plate has a low cost and a low heat conductivity coefficient, and can maintain sufficient strength at both ambient and high temperatures to avoid failure.
Disclosed in the present invention are a stabilization time measurement method for a weathering steel rust layer, and a storage medium. The method comprises the following steps: S1, after weathering steel is put, regularly measuring the thickness of a weathering steel rust layer, and recording the thickness of the weathering steel rust layer and the test time; S2, calculating logarithms of the thickness and the time at the initial stage and the later stage of formation of the rust layer to obtain two relation curves of the thickness logarithm and the time logarithm at the initial stage and the later stage of formation of the rust layer; S3, performing linear fitting on the two relation curves at the initial stage and the later stage of formation of the rust layer to obtain two relation straight lines of the thickness logarithm and the time logarithm at the initial stage and the later stage of formation of the rust layer; and S4, reading the time corresponding to an intersection point of the two relation straight lines as the stabilization time t1. According to the method, the rust layer does not need to be sampled in the measurement process, and is not damaged. The method is suitable for measuring the stabilization time of the weathering steel rust layer on the construction site, the measurement cost is low, and implementation is easy.
G01N 21/25 - ColourSpectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
G01B 7/06 - Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width, or thickness for measuring thickness
G01B 11/06 - Measuring arrangements characterised by the use of optical techniques for measuring length, width, or thickness for measuring thickness
G01B 17/02 - Measuring arrangements characterised by the use of infrasonic, sonic, or ultrasonic vibrations for measuring thickness
46.
X80-GRADE HOT-BENT ELBOW HAVING EXCELLENT WELDING PERFORMANCE, AND MANUFACTURING METHOD THEREFOR
Disclosed in the present invention are an X80-grade hot-bent elbow having an excellent welding performance, and a manufacturing method therefor. The present invention relates to the technical field of steel production. The chemical components and the mass percentages of the X80-grade hot-bent elbow are as follows: 0.05-0.08% of C, 0.10-0.30% of Si, 1.50-1.70% of Mn, P ≤ 0.015%, S ≤ 0.0030%, 0.040-0.060% of Nb, 0.030-0.050% of V, 0.006-0.020% of Ti, 0.10-0.30% of Cr, 0.60-0.80% of Ni, 0.20-0.30% of Mo, 0.10-0.30% of Cu, 0.005-0.015% of Al, 0.0008-0.0015% of Mg, B ≤ 0.0005%, N ≤ 0.0050%, no Ca, and the balance of Fe and inevitable impurities. The use of the magnesium metallurgy technology improves the post-welding performance of the product; since nucleation particles of the magnesium element are different, the crystal grains of the heat affected zone of the welding machine are effectively refined, and the performance of the welding heat affected zone and the welding zone is greatly improved.
The present invention relates to the technical field of steel production. Disclosed are a rare earth-containing NM600 wear-resistant steel plate and a preparation method therefor. The wear-resistant steel plate comprises the following chemical components and mass percentage: C: 0.21%-0.63%, Mn: 0.20%-1.00%, Si: 0.10%-0.30%, Cr: 0.15%-0.85%, Mo: 0.08%-0.75%, Ni: 0.70%-2.00%, Nb: 0.010%-0.060%, V: 0.010%-0.060%, Ti: 0.010%-0.040%, Alt: 0.020%-0.080%, B: 0.0008%-0.0030%, Ce: 0.0005%-0.0080%, P≤0.010%, S≤0.0020%, O≤0.0020%, N≤0.0040%, and the remainder is iron and unavoidable impurities. By adding a rare earth alloy into low-alloy high-strength wear-resistant steel, low-temperature impact toughness and plasticity are effectively improved without reducing the hardness and strength of the steel plate.
A wide and heavy steel plate having ultrahigh strength and containing rare earth and a preparation method therefor, which relate to the technical field of steel production. The steel plate comprises the following chemical components in percentages by mass: C: 0.10%-0.18%, Mn: 0.55%-1.35%, Si: 0.15%-0.35%, Cr: 0.20%-0.70%, Mo: 0.25%-0.65%, Ni: 0.85%-1.25%, Nb: 0.016%-0.044%, V: 0.025%-0.065%, Ti ≤ 0.010%, Al: 0.025%-0.070%, B: 0.001%-0.003%, P ≤ 0.015%, S ≤ 0.002%, T.O ≤ 0.0010%, N ≤ 0.0055%, Ce ≤ 0.0050 ppm, and the balance of iron and inevitable impurities. The steel plate has a tensile strength of 1400-1470 MPa, a yield strength of 1200-1300 MPa, an elongation of 10.0%-12.5%, a low temperature impact toughness at -40°C of 90-150 J, and a flatness of 3 mm/m and 5 mm/2m.
The present invention relates to the technical field of steel production. Disclosed are a plate for a thick-wall large-diameter grade X80M hot bending pipe and a manufacturing method therefor. The chemical components and the mass percent of the plate are as follows: C: 0.05%-0.15%; Si: 0.10%-0.40%; Mn: 1.50%-1.80%; P≤0.015%; S≤0.0050%; Nb: 0.030%-0.080%; V≤0.060%; Ti≤0.040%; Cr≤0.40%; Ni: 0.20%-1.00%; Mo: 0.15%-0.50%; Cu≤0.35%; Al: 0.015%-0.050%; Ca: 0.0005%-0.0040%; B≤0.0005%; N≤0.0050%; and the balance being Fe and inevitable impurities. By adopting a micro-alloyed near peritectic component design and a pure steel smelting technology, a small amount of proeutectoid ferrite, acicular ferrite and granular bainite multi-phase composite tissue are obtained by means of a rolling cooling process, so that the requirements of low-temperature toughness and high strength of a product are satisfied, and the subsequent use requirements of a hot bending pipe are satisfied.
The present invention relates to the technical field of steel production. Disclosed are a low-yield-ratio high-toughness Q500qE bridge steel and a production method thereof. The bridge steel comprises the following chemical components in percentage by mass: 0.04%-0.07% of C, 0.15%-0.25% of Si, 1.40%-1.55% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.03%-0.05% of Nb, 0.008%-0.02% of Ti, 0.020%-0.040% of Alt, 0.10%-0.20% of Cu, 0.20%-0.30% of Ni, 0.25%-0.40% of Cr, 0.10%-0.20% of Mo, 0.38%-0.45% of carbon equivalent (CEV), a welding crack sensitivity coefficient Pcm being 0.15%-0.23%, and the balance of Fe and a small amount of unavoidable impurities. The steel having a thickness specification of 10-60 mm is obtained by using the TMCP and tempering process, a metallographic structure using bainite and ferrite as main components is obtained, and good matching of high strength, low yield ratio and high low-temperature toughness is achieved.
The present invention relates to the technical field of iron and steel production. Disclosed are steel for a steel cord having a tensile strength greater than or equal to 4,000 MPa and a production method. The steel comprises the following chemical components in percentage by weight: C: 0.89-1.10 wt%, Si: 0.10-0.30 wt%, Mn: 0.20-0.60 wt%, P≤0.015 wt%, S≤0.010 wt%, Cr: 0.01-0.40 wt%, Ni: 0.01-0.20 wt%, Cu: 0.005-0.30 wt%, Al≤0.0020 wt%, Ti≤0.0016 wt%, N≤0.0070 wt%, and the balance of Fe and inevitable impurities. A steel wire rod is mainly composed of a sorbite structure, so as to avoid affecting the formation of a network cementite used in drawing; and the tensile strength of the final finished steel cord is 4,000 MPa or above, thereby satisfying the requirements of energy conservation, environmental protection and continuous increase of the strength of a lightweight automotive tire steel cord.
A production method for controlling a high-quality surface of a quenching plate, comprising the following steps: shot blasting; quenching heating: when residual oxygen exceeds 300 PPm, a nitrogen valve is fully opened and continues until the residual oxygen content in a furnace is less than or equal to 300 PPm, then an odd nitrogen charging valve and an even nitrogen charging valve are used, the nitrogen charging valves are continuously and circularly opened, and the nitrogen charging amount is sufficient; quenching cooling: first closing a group of low-pressure segments according to a sequence from back to front, measuring the temperature of a steel plate after the steel plate leaves a quenching machine, if the temperature is low, closing another group until the temperature of the steel plate after quenching is 15-80°C, and drying the surface of the steel plate; and tempering heating: tempering is performed by means of a radiant tube furnace, when the residual oxygen exceeds 300 PPm, the nitrogen valve is fully opened and continues until the residual oxygen content in the furnace is less than or equal to 300 PPm, then the odd nitrogen charging valve and the even nitrogen charging valve are used, the nitrogen charging valves are continuously and circularly opened, and the nitrogen charging amount is sufficient. By controlling the surface roughness of the steel plate and the oxygen content in a thermal treatment furnace, the quenching plate having a high-quality surface can be produced.
The present invention discloses a method for preparing a special high wear-resistance steel strip NGNM01 for pipeline transportation, and relates to the technical field of steel production. By means of a strict "triple-control operation" production process for steel rolling, the purposes of high steel purity, good structure uniformity and few decarburized layers on the surface are achieved. NGNM01 has high wear resistance, and the Rockwell hardness thereof after quenching and tempering reaches 62-65 HRC; 90º bending detection shows that NGNM01 has good toughness; in a high-speed friction environment, NGNM01 can work at -40 to 250ºC and has high contact fatigue resistance; and NGNM01 has stable performance and strong market competitiveness. By means of eccentric bottom tapping, the amount of roughing slag is greatly reduced, such that the oxidability of molten steel is greatly reduced; therefore, the yield of alloy elements can be increased, the utilization amount of a carburant is reduced, the production cost is lowered, and the purposes of reducing the content of inclusions in steel and improving the purity of the molten steel can be achieved.
C21D 8/02 - Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
C21D 1/74 - Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
B21B 1/22 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling bands or sheets of indefinite length
54.
STAINLESS STEEL COMPOSITE PLATE FOR WEATHERING STEEL BRIDGE HAVING LOW YIELD RATIO
Disclosed in the present invention is a stainless steel composite plate for a weathering steel bridge having a low yield ratio, comprising a base material and a covering material which satisfy that an atmospheric corrosion resistance index I is greater than or equal to 6.0, the total thickness being 5-60 mm, and the thickness of the covering material being 0.5-5.0 mm. A preparation method for the stainless steel composite plate comprises: base material and covering material preparation, single-surface blank making, symmetrical blank making, controlled rolling and controlled cooling, tempering heat treatment, and plate splitting and straightening. According to the stainless steel composite plate provided by the present invention, composite interface bonding is good, the shear strength is greater than or equal to 300 MPa, and no crack occurs after the stainless steel composite plate is bent by 180°; a yield ratio is less than or equal to 0.83; the impact energy of the base material at -40°C is greater than or equal to 220 J; and after the covering material is subjected to intergranular corrosion, no intergranular corrosion phenomenon is found, and the covering material has excellent intergranular corrosion resistance.
Disclosed in the present invention are magnesium-containing steel 45 and a preparation process therefor. The present invention relates to the technical field of steel production. The steel 45 comprises the following chemical components, in percentages by mass: 0.45-0.48% of C, 0.17-0.37% of Si, 0.65-0.80% of Mn, P≤0.035%, S≤0.035%, 0.0005-0.0020% of Mg, and the balance of iron and inevitable impurities. On the basis of ensuring the safe production of the steel 45, inclusions in the steel are modified by means of feeding a magnesium-silicon cored wire into molten steel at the final stage of refining, such that the inclusions in the steel are converted into fine and dispersively distributed sulfide-oxide composite inclusions, the rating of the inclusions is optimized, and the comprehensive mechanical property of the steel 45 is improved.
C22C 33/06 - Making ferrous alloys by melting using master alloys
B21B 1/00 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations
B21B 37/74 - Temperature control, e.g. by cooling or heating the rolls or the product
B22D 11/18 - Controlling or regulating processes or operations for pouring
56.
500 MPA GRADE LOW YIELD RATIO WEATHER-RESISTANT BRIDGE STEEL AND MANUFACTURING METHOD THEREFOR
Disclosed is 500-MPa low-yield-ratio weather-resistant bridge steel and a manufacturing method therefor; the weather-resistant bridge steel includes the following components in percentage by mass: C: 0.04%-0.09%, Si: 0.15%-0.30%, Mn: 1.40%-1.50%, P: 0.009%-0.015%, S: ≤0.002%, Nb: 0.020%-0.050%, Ti: 0.010%-0.020%, V: 0.010%-0.030%, Cu: 0.30%-0.40%, Ni: 0.30%-0.45%, Cr: 0.45%-0.60%, Mo: 0.08%-0.15%, Alt: 0.02%-0.04%, and the balance Fe and inevitable impurities; through scientific component designing and a matched manufacturing method combining controlled rolling and cooling and tempering, the weather-resistant bridge steel has a low yield ratio, high low-temperature toughness and high elongation.
A nickel-free LPG marine steel plate and a manufacturing method therefor belong to the technical field of high-strength structural steels; the steel plate consists of the following chemical components by mass percentage: 0.18 to 0.24% of C, 0.10 to 0.19% of Si, 16.1 to 18.9% of Mn, less than or equal to 0.012% of P, 0.15 to 0.35% of Mo, 0.10 to 0.25% of RE, and the balance of Fe and inevitable impurities; the steel plate has a yield strength of ≥410 MPa and an impact absorption work of ≥66 J at 150° C., has good low-temperature mechanical properties, can replace 5Ni and 9Ni-based steel, and is used for constructing an LPG storage tank and a relevant structural member at low costs.
A micro-molybdenum-type weather-resistant bridge steel plate, which is made by smelting the following components according to weight ratio: 0.05 to 0.08% C, 0.30 to 0.50% Si, 1.25 to 1.35% Mn, 0.010 to 0.014% P, S≤0.003%, 0.020 to 0.030% Nb, 0.010 to 0.020% Ti, 0.040 to 0.050% V, 0.25 to 0.40% Cu, 0.25 to 0.35% Ni, 0.45 to 0.55% Cr, 0.03 to 0.08% Mo, 0.020 to 0.040% Alt, and the remainder is Fe and impurities. The content of micro-molybdenum reduces the production costs of the steel plate. The steel plate has a yield strength of 500 to 600 MPa, the yield ratio is less than or equal to 0.85, and the maximum thickness of the steel plate may reach 80 mm.
Disclosed is a multi-wire submerged arc welding method for a Q370qE thick plate. A double-U groove having truncated edge slopes, and H10Mn2A welding wires are used. Moreover, elements such as C, Mn, P, and S are specially agreed in a welding material technical agreement, and the performance of high toughness at low temperature of weld metal is ensured by means of combination optimization of the contents of the elements. The present invention is low in process cost, simple to operate, and excellent in welding process performance. The formed weld metal has the characteristic of high toughness at low temperature, and the strength thereof matches that of base metal, so that a welded joint has the mechanical properties of high strength and excellent low-temperature toughness, and can meet the technical requirements for welded super-thick plates suitable for bridge steel.
Disclosed is a ferrite-pearlite Q345qD bridge steel extra-thick plate and a preparation method therefor, relating to the field of steel production technology. The chemical composition and the mass percentages thereof are as follows: C: 0.13-0.16%, Si: 0.20-0.40%, Mn: 1.40-1.70%, P≤0.015%, S≤0.005%, Nb: 0.020-0.050%, V: 0.020-0.050%, Al: 0.015-0.045%, Ti: 0.008-0.025%, Ni: 0.15-0.35%, and the balance being Fe and inevitable impurities; and the normalized state of the steel plate is mainly ferrite and pearlite. The mechanical performance of the steel plate under normalized delivery condition involves: a yield strength of ReL 329-346 MPa, a tensile strength of Rm≥500 MPa, an elongation rate of A%≥20%, and a longitudinal impact energy single value at -20ºC≥120 J, with no cracks occurring during transverse bending.
The present invention relates to the technical field of steel production. Disclosed are a 1000 MPa-grade quenched and tempered hydroelectric steel plate and a production method therefor, comprising the following chemical components in percentage by weight: C: 0.08％-0.11％; Mn: 1.00％-1.50％; Si: 0.10％-0.50％; P≤0.012％; S≤0.003％; Alt: 0.050％-0.080％; V: 0.040％-0.060％; Ti: 0.008％-0.020％; Ni: 1.00％-1.70％; Cr: 0.30％-0.60％; Mo: 0.40％-0.60％; B: 0.001％-0.002％; Pcm≤0.26％; and the balance being Fe and impurities. The 1000 MPa-grade quenched and tempered hydroelectric steel plate is obtained, the maximum thickness of the steel plate reaches 56 mm, the yield strength is greater than or equal to 885 MPa, and the tensile strength is 950-1130 MPa. The transverse low-temperature impact energy of the steel plate at a temperature of -60℃ is greater than or equal to 100 J. Since the carbon content is low and the welding cold crack sensitivity coefficient Pcm is less than or equal to 0.26%, the steel plate can be used at a low preheating temperature, and the welding quality and the welding efficiency of a hydropower engineering project construction site are improved.
A low-cost high energy welding-resistant 420 MPa-grade bridge steel and a production method therefor, relating to the technical field of steel production, the chemical components and the mass percentages thereof being as follows: C: 0.03％-0.10％, Si: 0.20％-0.40％, Mn: 1.40％-1.70％, P≤0.015％, S≤0.005％, Nb: 0.020％-0.050％, Al: 0.015％-0.045％, Ti: 0.008％-0.020％, B: 0.0005％-0.0020％, N: 0.0040％-0.0080％, and the remainder being Fe and unavoidable impurities. The low-temperature toughness of the welding heat-affected zone is ensured, the structure of the steel plate is uniform, the yield-strength ratio is low, and various performance indexes are good.
22 gas shielded welding wire for an ultra-low temperature high manganese steel and a preparation method, comprising the following raw materials by weight: 0.15-0.35 wt% of C, 23-25 wt% of Mn, 0.60-0.90 wt% of Si, 4.0-6.0 wt% of Ni, 3.0-4.5 wt% of Cr, P≤0.010 wt％, S≤0.006 wt％, and the balance of Fe and inevitable impurities. The raw materials are subjected to hot rolling to form a wire rod, the wire rod is subjected to multiple annealing and drawing to form a straight bar, and copper is plated on the surface of the straight bar to prepare a welding wire. The welding wire prepared in the present invention is low in cost and simple in alloy component system; formed weld metal is excellent in low-temperature toughness, the strength of the formed weld metal is matched with that of ultra-low temperature high manganese steel, and the technical requirements of welding the ultra-low temperature high manganese steel for the strength and ultra-low temperature toughness are met.
Disclosed are a submerged arc welding wire for ultra-low temperature high manganese steel, and a preparation method. The submerged arc welding wire comprises the following raw materials by weight fraction: 0.10-0.30 wt% of C, 24-26.5 wt% of Mn, 0.12-0.30 wt% of Si, 4.0-6.0 wt% of Ni, 4.0-6.0 wt% of Cr, less than or equal to 0.010 wt% of P, less than or equal to 0.006 wt% of S, and the balance of Fe and inevitable impurities. The raw materials are hot rolled into a wire rod, the wire rod is then drawn to a straight rod by means of multiple times of annealing, and the surface is plated with copper, thereby obtaining the welding wire. The welding wire prepared in the present invention is low in cost and simple in alloy composition system; a weld metal formed is excellent in low-temperature toughness and has the strength matching ultra-low temperature high manganese steel, and the technical requirements of welding for strength and ultra-low temperature toughness suitable for ultra-low temperature high manganese steel are satisfied.
The present disclosure discloses a 690 MPa high-strength medium-manganese steel with low yield ratio and medium thickness and a manufacture method thereof, which relates to the technical field of steel smelting. The 690 MPa high-strength medium-manganese steel with low yield ratio and medium thickness is composed of the following chemical composition in mass percentage: C: 0.05%-0.10%, Mn: 4.1%-4.7%, Si: 0.15%-0.4%, P≤0.010%, S≤0.003%, Ti: 0.01%-0.05%, Ni+Cr+Mo≤0.6%, and the balance of Fe and unavoidable impurities. The steel plate manufactured meets the safety performance and construction cost requirements of the construction machinery on the ultra-high-strength steel in complex environments.
A 390 MPa-grade full-position gas-shielded welding wire for a secondary fire-resistant building and a fabrication method. Chemical components of the gas-shielded welding wire comprise: C: 0.035-0.061 wt%, Si: 0.30-0.45 wt%, Mn: 0.90-1.10 wt%, Cr≤0.15 wt%, Ni: 0.70-0.85 wt%, Mo: 0.45-0.55 wt%, Cu≤0.08 wt%, P≤0.008 wt%, and S≤0.005 wt%, the remainder being Fe and inevitable impurities. The gas-shielded welding wire can be used for welding steel which has a matching strength for use in a secondary fire-resistant building, the welding joints of said welding having excellent performance and being able to withstand a secondary fire, such that the construction and use of secondary fire-resistant buildings can be effectively promoted, thereby improving the fire-resistant safety of such buildings and playing a vital role in the construction of future fire-resistant buildings.
A 460 MPa-grade all-position gas shielded welding wire for a building resistant to secondary fire and a manufacturing method. The chemical components of the gas shielded welding wire are: C: 0.060-0.080 wt％; Si: 0.35-0.50 wt％; Mn: 1.10-1.25 wt％; Cr≤0.15wt％; Ni: 0.80-0.95 wt％; Mo: 0.45-0.55 wt％; Cu≤0.08 wt％; P≤0.008 wt％; S≤0.005 wt％; and the balance being Fe and inevitable impurities. The gas shielded welding wire has excellent mechanical properties, can withstand secondary fire, can effectively promote construction and application of the building resistant to secondary fire, improves the fire-resistant safety of the building, and saves reconstruction costs after primary fire.
A steel plate for an American standard container under low-temperature service conditions, and a production method therefor, which relate to the technical field of steel production. The steel plate comprises the following chemical components in percentages by mass: 0.12-0.17% of C, 0.20-0.40% of Si, 1.35-1.50% of Mn, P ≤ 0.010%, S ≤ 0.005%, 0.25-0.35% of Ni, 0.01-0.020% of Nb, 0-0.020% of V, 0.02-0.05% of Al, 0-0.010% of Ti, 0.05-0.10% of Mo and the balance being Fe and inevitable impurities. Low-temperature controlled rolling and controlled cooling and suitable normalizing heat treatment are used, such that a heat treatment process of rapid cooling and tempering after normalizing is omitted; and the produced steel plate for an American standard container under low-temperature service conditions has high strength, the tensile strength is not less than 485 MPa, and the delivery state and PWHT state low-temperature impact toughness results are excellent.
Provided are an API 2W-50 steel plate for an offshore oil platform, and a production method therefor, which relate to the technical field of steel production. The API 2W-50 steel plate comprises the following chemical components in percentage by weight: C: 0.06% - 0.08%, Mn: 1.45% - 1.55%, Si: 0.15% - 0.25%, P≤0.013%, S≤0.003%, Nb: 0.020% - 0.030%, V≤0.006%, Ti: 0.007% - 0.020%, Alt: 0.025% - 0.050%, Cr: 0.13% - 0.19%, Ni: 0.30% - 0.40%, Mo≤0.08%, Cu≤0.35%, N≤0.006%, H≤0.006%, CEV≤0.38% and Pcm≤0.20%, with the balance being Fe and impurities. The API 2W-50Z steel plate meets the performance requirements of standard API-2W-2019, the transverse impact toughness Akv at -40ºC at 1/2 the thickness of the steel plate is ≥ 300 J, and the Z35 performance in the thickness direction of the steel plate is ≥ 60%; and CEV is designed to be ≤ 0.38%, Pcm is designed to be ≤ 0.20%, and the welding performance of the steel plate is much improved.
A submerged-arc welding process for thick-gauge TMCP-state high-strength low-yield-ratio bridge steel. The process uses welding materials and welding process parameters that match with high-performance bridge steel. The welding wire mark is CHW-S80CF, the welding flux mark is CHF606, and the tensile strength of a welding wire is more than 850 Mpa. Symmetrical V-shaped grooves are used for welding, and low temperature preheating is performed before the welding. The welding current, arc voltage, welding speed and welding heat input parameters during priming and filling are set during the welding. Under the condition of a large heat input, the low-temperature toughness, strength and cold bending performance of a welded joint are taken into account. The impact toughness of all parts of the joint at -40°C is higher than 60 J, and the joint has an excellent toughness matching degree and cold bending forming performance.
The present invention relates to the technical field of metal materials, and disclosed are a high-manganese steel wire rod for welding and a steel rolling process therefor. By alloying C, Mn and Cr and in combination with a certain amount of Ni, the material has an austenite structure and excellent properties, and a steel wire rod having excellent plasticity is prepared by means of a matching steel rolling process. In the present invention, the steel wire rod is made into a welding rod or welding wire and then welded, and a weld metal formed has impact energy of more than 60 J at a temperature of -269°C and has excellent low-temperature toughness. Compared with a stainless-steel wire rod having a similar use, the content of Ni is reduced by more than 50%, a nickel-saving effect is significant, and the cost is greatly reduced. According to the present invention, the steel wire rod is particularly suitable for manufacturing a high-manganese low-temperature steel matching welding material, and constructing a low-temperature storage-transport vessel required for liquefied ethylene, liquefied natural gas, liquid hydrogen or liquid helium.
Disclosed is a gear steel bar with controlled rolling and high-temperature tempering. The gear steel bar comprises the following components in percentage by weight: 0.15-0.25 % of C, 1.00-1.50 % of Mn, less than or equal to 0.35 % of Si, less than or equal to 0.030 % of P, less than or equal to 0.030 % of S, less than or equal to 1.00-1.50 % of Cr, 0.010-0.045 % of Al, and the balance being Fe and unavoidable impurities.
Disclosed are an efficiently welded bridge steel and a fabrication method therefor, which relate to the technical field of iron and steel production. The efficiently welded bridge steel comprises the following chemical components in mass percentage: C: 0.05％-0.08％; Si: 0.10％-0.30％; Mn: 1.10％-1.50％; P≤0.015％; S≤0.0050％; Nb: 0.020％-0.040％; V: 0.010％-0.040％; Ti: 0.006％-0.020％; Cr≤0.05％; Ni: 0.10％-0.30％; Mo≤0.05％; Cu≤0.05％; B≤0.0005％; Al: 0.025％-0.050％; Mg: 0.0010％-0.0030％; N≤0.0050％; Ca is not added, and the remainder is Fe and impurities. Finely dispersed inclusions having magnesium oxide, magnesium sulfide and magnesium aluminate spinel as nuclei are generated by means of metallurgical technology, and a TMCP rolling process and a normalizing treatment are used to obtain ferrite and a small number of pearlite structures having magnesium particles as nucleation conditions, so that the welding performance of bridge steel is improved.
Disclosed in the present invention are a high-toughness quasi-sub-temperature quenched 09MnNiDR container steel and a preparation method therefor, which relate to the technical field of steel production. The high-toughness quasi-sub-temperature quenched 09MnNiDR container steel comprises the following chemical components in percentage by mass: ≤0.10% of C, 0.15%-0.50% of Si, 1.20%-1.60% of Mn, ≤0.015% of P, ≤0.010% of S, 0.30%-0.80% of Ni, ≥0.02% of Alt, ≤0.040% of Nb, ≤0.040% of V, ≤0.020% of Ti, and 0.0010%-0.0040% of Ca, the balance being Fe and residual elements. Provided that the strength of the steel plate is not reduced, the core impact performance of a 09MnNiDR steel plate with a thickness of 40-80 mm is improved.
Disclosed in the present invention is a non-quenched and tempered steel weather-resistant high-strength bolt, comprising the following chemical components in percentage by mass: 0.17-0.23% of C; Si≤0.30; 1.25-1.60 of Mn; P≤0.02; S≤0.015%; 0.4-0.6% of Cr, Ni≤0.3%; V≤0.08%; Nb≤0.05%; Ti≤0.04; 0.37-0.41 of Cu; 0.01-0.035 of Al; 0.006-0.012 of N; and O≤0.0015, with the balance being Fe and inevitable impurities. The M6 bolt manufactured in the present invention has the tensile strength of greater than or equal to 810 MPa, the elongation after fracture of greater than or equal to 10%, and the reduction of area of greater than or equal to 55%, and has the technical effects of high tensile strength, good plastic toughness and excellent atmospheric corrosion resistance.
Disclosed in the present invention are free-cutting and non-quenched and tempered steel and a manufacturing method therefor. The cracking and deterioration of mechanical properties of a rolled material caused by sulfide are mitigated by developing a proper heating schedule and rolling process without increasing production costs and energy consumption. The use of a three-stage heating method and measures such as increasing an initial rolling temperature and reducing a finishing rolling temperature not only effectively improves the crack resistance of the rolled material, but also enables various microalloying elements to dissolve in a steel matrix as much as possible to improve the mechanical properties of a product. Additionally, the use of measures such as water spray at a high-pressure, ring welding processing of an end part, air cooling on a cooling bed, and grinding of the rolled material surface further lowers the probability of cracking during rolling and improves the surface quality of the product. A free-cutting and non-quenched and tempered steel product produced using the rolling method provided in the present invention has a higher yield and better properties.
C21D 8/00 - Modifying the physical properties by deformation combined with, or followed by, heat treatment
B21C 37/00 - Manufacture of metal sheets, rods, wire, tubes, profiles or like semi-manufactured products, not otherwise provided forManufacture of tubes of special shape
77.
HOT ROLLED HIGH STRENGTH STEEL LONG-SHANK BOLT AND MANUFACTURING METHOD THEREFOR
The present invention relates to the technical field of steels for use in fasteners. Disclosed are a hot rolled high strength steel long-shank bolt and a manufacturing method therefor. The hot rolled high strength steel long-shank bolt obviates two processes, namely spheroidize annealing and a tempering treatment, saves energy, and reduces costs. During a manufacturing process, a wire of which the strength is 76-84% of that of a final product is produced by means of controlled rolling and controlled cooling, then during a drawing process, the drawing reduction ratio is controlled at 10-50% so that the strength of the drawn wire is 89-96% of that of the final product, and then a scheme of simultaneously performing straightening and rolling is utilized to ensure straightness and, at the same time, to allow the wire to attain the strength of the final product, thus significantly increasing the dimensional precision, strength, and fatigue performance of the final product bolt.
C22C 38/02 - Ferrous alloys, e.g. steel alloys containing silicon
C22C 38/04 - Ferrous alloys, e.g. steel alloys containing manganese
C22C 38/06 - Ferrous alloys, e.g. steel alloys containing aluminium
C22C 38/12 - Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium or niobium
C22C 38/14 - Ferrous alloys, e.g. steel alloys containing titanium or zirconium
C22C 38/24 - Ferrous alloys, e.g. steel alloys containing chromium with vanadium
B21B 1/16 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling wire or material of like small cross-section
B21C 1/02 - Drawing metal wire or like flexible metallic material by drawing machines or apparatus in which the drawing action is effected by drums
B21F 45/16 - Wire-working in the manufacture of other particular articles of devices for fastening or securing purposes
C21D 8/00 - Modifying the physical properties by deformation combined with, or followed by, heat treatment
78.
WEATHER-RESISTANT BRIDGE STEEL AND SMELTING METHOD THEREFOR
Disclosed are a weather-resistant bridge steel and a smelting method therefor, which relate to the technical field of iron and steel production. The weather-resistant bridge steel comprises the following chemical components in percentage by mass: C: 0.030% - 0.080%, Si: 0.10% - 0.40%, Mn: 1.50% - 1.80%, P ≤ 0.015%, S ≤ 0.0010%, Nb: 0.030% - 0.050%, V: 0.005% - 0.050%, Ti: 0.006% - 0.020%, Cr: 0.20% - 0.80%, Ni: 0.05% - 0.20%, Mo ≤ 0.05%, Cu: 0.05% - 0.20%, B ≤ 0.0005%, Al: 0.005% - 0.015%, Mg: 0.0008% - 0.0015%, N ≤ 0.0050%, and the balance being Fe and inevitable impurities. A top-bottom combined blowing converter is used for smelting, so that the inclusion size is effectively reduced by means of LF+RH refining treatment and magnesium treatment, the structure grain size is refined, the forming rate of acicular ferrite is increased, the welding performance is effectively improved, and the corrosion resistance of a steel plate is improved.
Disclosed are a high-toughness heat-resistant flat-bulb steel for a ship and a preparation method for the flat-bulb steel. The preparation method comprises: adding CaO, 40% blast furnace molten iron, waste steel, MnFe, SiFe, NiFe, NbFe, and TiFe alloy materials and auxiliary materials into a converter or an electric furnace for performing melting; then adding FeO for P removal; performing sampling analysis of the content of alloy elements, and adjusting target values; performing S removal treatment by using a ladle furnace (LF), then vacuum degassing, and finally performing continuous casting to form a casting blank; and performing rolling and thermal treatment to obtain a finished flat-bulb steel product. The prepared flat-bulb steel in the present invention has the room-temperature yield strength larger than or equal to 610 MPa, and has +700°C yield strength larger than or equal to 470 MPa, and ensures -120°C impact absorbing energy to be larger than or equal to 90 J; the flat-bulb steel has better safety in building structural parts such as reinforcing ribs of storage tanks for liquefied natural gas and ethylene etc. and hull frameworks of low-temperature energy ships.
The present invention relates to the technical field of steel production. Disclosed are a 13MnNi6 steel for a cryogenic liquid hydrocarbon storage tank and a manufacturing method therefor. The 13MnNi6 steel for a cryogenic liquid hydrocarbon storage tank comprises the following chemical compositions in percentage by mass: C: 0.10%-0.15%, Si: 0.20%-0.40%, Mn: 1.30%-1.50%, P: ≤0.015%, S: ≤0.0050%, Ni: 0.50%-0.80%, Nb: 0.015%-0.050%, Ti: 0.006%-0.020%, Cr: 0.10%-0.30%, Al: 0.005%-0.015%, Mg: 0.0008%-0.0015%, N:≤0.0050%, the remainder being Fe, and unavoidable impurities without Ca. The microalloying technology is used to effectively reduce the size of an inclusion, reduce the original austenite grain size, and refine structure grains, and by means of TMCP rolling and heat treatment processes, the product strength and low-temperature toughness are improved, and the welding performance of a steel plate is improved.
Disclosed are a high-toughness and high-aging impact steel plate and a manufacturing method therefor, and the present invention relates to the technical field of steel production. The high-toughness and high-aging impact steel plate comprises the following chemical components by mass percent: 0.12-0.22% of C, 0.10-0.60% of Si, 1.15-1.60% of Mn, less than 0.020% of P, less than 0.015% of S, with the following one or more alloy elements being added: 0-0.060% of Nb, 0-0.12% of Ti and 0.010-0.050% of Al, with the balance being iron and inevitable impurity elements. The steel plate can withstand and resist complex marine stress at a low temperature of -40°C, the lowest yield strength thereof is 345 MPa, same has good toughness at a low temperature of -40°C, excellent aging performance, and also has good welding performance and a low carbon equivalent.
The present invention relates to the technical field of steel production, and provides an N08825 composite steel plate for a high-corrosion-resistance container, comprising a base layer and a coating which are in a metallurgical bonding state. The base layer comprises the following chemical components in percentage by mass: C≤0.20%, Si≤0.55%, Mn: 0.5%-1.7%, Cu≤0.30%, Ni≤0.30%, Cr≤0.30%, Mo≤0.08%, Nb≤0.050%, V≤0.050%, Ti≤0.030%, Alt≥0.020%, P≤0.025%, S≤0.010%, Cu+Ni+Cr+Mo≤0.70%, and the balance of Fe and other inevitable impurities. The coating is N08825 and comprises the following chemical components in percentage by mass: Ni: 38.0%-46.0%, Cr: 19.5%-23.5%, Fe≥22.0%, Mn≤1.00%, C≤0.05%, Cu: 1.5%-3.0%, Si≤0.5%, S≤0.030%, Al≤0.2%, Ti: 0.6%-1.2%, and Mo: 2.5%-3.5%.
B32B 15/01 - Layered products essentially comprising metal all layers being exclusively metallic
B32B 15/18 - Layered products essentially comprising metal comprising iron or steel
B32B 7/10 - Interconnection of layers at least one layer having inter-reactive properties
B32B 37/10 - Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the pressing technique, e.g. using direct action of vacuum or fluid pressure
B32B 37/06 - Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the heating method
B32B 37/08 - Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the cooling method
B32B 37/24 - Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer not being coherent before laminating, e.g. made up from granular material sprinkled onto a substrate
C22C 38/04 - Ferrous alloys, e.g. steel alloys containing manganese
C22C 30/02 - Alloys containing less than 50% by weight of each constituent containing copper
B21B 1/38 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling sheets of limited length, e.g. folded sheets, superimposed sheets
83.
CRACK ARREST STEEL PLATE FOR BCA2-GRADE CONTAINER SHIP AND MANUFACTURING METHOD FOR CRACK ARREST STEEL PLATE
The present invention relates to the technical field of steel production. Disclosed is a crack arrest steel plate for a BCA2-grade container ship. The crack arrest steel plate comprises the following chemical components by mass percentage: 0.04%-0.10% of C, 1.60%-2.00% of Mn, 0.30%-0.60% of Ni, 0.005%-0.05% of Nb, 0.005%-0.02% of Ti, 0.015%-0.060% of Al, 0.01%-0.25% of Cr, 0.10%-0.35% of Cu, 0.10%-0.40% of Si, not more than 0.010% of P, not more than 0.004% of S, and the balance being Fe and other inevitable impurities. Ferrite is induced to be separated out by means of grain boundary deformation, generation of carbide at the grain boundary is suppressed, the crack initiation probability is reduced, and the crack initiation energy is increased; and coarse carbide particles between bainite strip bundles are refined, the amount of coarse carbide is reduced, the length of a crack propagation path is increased, the brittle crack propagation resistance is effectively increased, and thus the crack arrest toughness is remarkably improved.
C21D 8/02 - Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
C21D 9/00 - Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor
B21B 1/22 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling bands or sheets of indefinite length
84.
LOW-COST HIGH-PERFORMANCE Q500 BRIDGE STEEL AND PRODUCTION METHOD THEREFOR
Disclosed in the present invention is a low-cost high-performance Q500 bridge steel, relating to the technical field of steel production. The Q500 bridge steel comprises the following chemical components in percentage by mass: C≤0.035%, Si: 0.31%-0.40%, Mn: 1.71%-1.80%, P≤0.015%, S≤0.0030%, Nb: 0.030%-0.050%, V: 0.020%-0.050%, Ti: 0.010%-0.018%, Cr: 0.70%-0.80%, Ni: 0.10%-0.20%, residual Mo≤0.05%, Cu: 0.10%-0.20%, B≤0.0005%, N≤0.0005%, and Al: 0.020%-0.050%. The tensile strength of the product is improved while the yield strength is reduced, effectively reducing the yield ratio of the product.
The present invention relates to the technical field of steel production. Disclosed is low-cost high-performance Q370qE-HPS bridge steel, comprising the following chemical components in mass percentage: C: 0.05%-0.08%, Si: 0.10%-0.40%, Mn: 1.61%-1.70%, P≤0.015%, S≤0.0030%, Nb: 0.030%-0.050%, Ti: 0.010%-0.018%, residual Ni≤0.05%, Cr: 0.20%-0.30%, residual Mo≤0.05%, residual Cu≤0.05%, residual B≤0.05%, N≤0.005%, Al: 0.020%-0.050%, and the balance of Fe and impurities. By using a TMCP rolling process, a bridge steel plate which has a low yield ratio and excellent welding performance and satisfies standard requirements is obtained, thereby improving market competitiveness of enterprises.
Disclosed is a method for rolling a wide Ni-Fe-Cr heat-resistant alloy thick plate. By means of the optimization of heating, rolling and heat treatment processes, a wide Ni-Fe-Cr heat-resistant alloy thick plate having the width of not less than 3350 mm is stably produced using a medium-thickness plate rolling mill, and the diameter of a pipe molded by means of "single longitudinal welding" is increased. The wide heat-resistant alloy thick plate has a high production difficulty and a high additional value, so that very high economic benefits can be created.
B21B 1/38 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling sheets of limited length, e.g. folded sheets, superimposed sheets
87.
EW 420 EXTRA THICK MARINE STEEL SHEET AND MANUFACTURING METHOD THEREFOR
An EW 420 extra thick marine steel sheet, which relates to the technical field of steel production. Internal defects such as blank segregation and loosening are reduced and the inclusion elements As, Sn, Sb, Pb, Bi and B are controlled by smelting clean steel; columnar crystals are crushed and austenite grains are refined by means of rough rolling at high temperature, at a low speed and under high pressure; and the objective of controlling tissue morphology and grain size is obtained by means of finish rolling cumulative deformation and cooperative cooling control.
AkvAkv impact absorption power value is greater than or equal to 27 J, the welding performance is good, the core hardness is not less than 80% of the surface hardness, and the low-temperature impact performance is also good.
A high-strength vessel plate having excellent low-temperature toughness and a manufacturing method, relating to the technical field of iron and steel production. The high-strength vessel plate comprises the following chemical components in mass percentage: 0.07% to 0.11% of C, 0.10% to 0.30% of Si, 1.30% to 1.60% of Mn, 0.40% to 0.80% of Ni, 0.05% to 0.12% of Mo, 0.02% to 0.05% of V, 0.02% to 0.05% of Alt, 0.008% or less of P, and 0.002% or less of S, with the balance being Fe and inevitable impurities. By adding a small amount of alloy to implement material strength upgrade, the alloy cost is low, accurate control is easily achieved, the use temperature is lower, and the strength is significantly improved, thus the material consumption for storage tank construction can be reduced.
22 values in 1/4 thickness and the core at -70°Ϲ are greater than or equal to 150 J, the yield strength is greater than or equal to 420 MPa, the tensile strength is greater than or equal to 560 MPa, and the present invention can be applied to construction of large low-temperature spherical tanks or storage tanks.
An 800 MPa construction machinery medium-manganese medium-thickness steel and a manufacturing method therefor, relating to the technical field of steel and iron smelting, wherein the chemical constituents and the mass percentages thereof are as follows: C: 0.05-0.08%, Mn: 4.8-5.8%, Si: 0.10-0.35%, P≤0.010%, S≤0.003%, Ti: 0.01-0.05%, Ni + Cr + Mo: 0.7-1.2%, with the balance being Fe and inevitable impurities. The medium-thickness steel can achieve excellent core mechanical properties that common 800 MPa-grade high-strength structure steel does not have, and meets the requirements for the ultra-high strength steel safety performance and low manufacturing cost in complex and severe environments in the construction machinery industry.
22 of a weld seam and a heat affected zone at -101℃ is larger than or equal to 34 J, the side bending d of the welded joint is equal to 4a, qualification is achieved at 180℃, and the welded joint has excellent mechanical comprehensive performance.
Disclosed is a method for producing a nickel-based steel from a high phosphorus molten iron, the method comprising using converter smelting, wherein the P content of the molten iron used is 0.130-0.150%; a process involving slag retention in the early stages and slag doubling in the later stages is used; the final smelting temperature is 1580-1620ºC; the bottom stirring flow is 350-400 NL/min in the middle and later periods of smelting; the basicity of the final slag is 4.0; the control amount of the final slag is 10-12 tons; a decarburization rate of ≥99% and a dephosphorization rate ≥96% in the converter are achieved; LF refining, a RH vacuum treatment, and arc continuous casting machine pouring are performed; TMCP rolling is used; the temperature is cooled to 300±20ºC by means of ACC water cooling and then to room temperature by means of air cooling; and a steel plate is heated to 550±10ºC, tempered for 3×h minutes, with h being the thickness of the plate, and is then air cooled to room temperature.
A low-temperature high-manganese austenitic steel rapid alloying process, comprising manganese alloy baking→converter tapping and tapping alloying→LF slag alloying, and specifically: (1) preparing a ladle the ladle age of which is in an early stage; (2) preparing a ladle support piece and transporting the manganese alloy that requires baking into the ladle; (3) ladle alloy baking; (4) controlling the tapping amount and tapping temperature of a converter; (5) LF refining furnace temperature rise alloying process; and (6) LF refining furnace large argon stirring, cooling and alloying process. The alloying process reduces the manganese alloying time of high-manganese austenitic steel from eight hours to within three hours, improving production efficiency and molten steel quality.
690 MPa-graded easy-to-weld corrosion-resisting high-strength steel and a manufacturing method therefor. Components (wt%) of the steel are as follows: C: 0.13%-0.23%; Si: 0.10%-0.60%; Mn: 0.80%-1.90%: P: <0.018%; S: <0.008%; Cr: 0-0.50%; Ni: 0-0.60%; Mo: 0-0.45%; Cu: 0-0.40%; Nb: 0-0.060%; V: 0-0.15%; Ti: 0-0.120%; B: 0-0.0035%; and Al: 0.010%-0.050%. An even and fine troostitic structure is obtained during heat treatment in alloy component design, good mechanical properties and fatigue properties are obtained, welding performance and corrosion resistance are more excellent, and the steel adapts to production and manufacturing in engineering machinery, mining machinery, harbor machinery and other industries.
A nickel-free LPG marine steel plate and a manufacturing method therefor belong to the technical field of high-strength structural steels. Said steel plate consists of the following chemical components by mass percentage: 0.18 to 0.24％ of C, 0.10 to 0.19% of Si, 16.1 to 18.9% of Mn, less than or equal to 0.012% of P, 0.15 to 0.35% of Mo, 0.10 to 0.25% of RE, and the balance of Fe and inevitable impurities. The steel plate has a yield strength of ≥ 410 MPa and an impact absorption work of ≥ 66 J at 150 °C, has good low-temperature mechanical properties, can replace 5Ni and 9Ni-based steel, and is used for constructing an LPG storage tank and a relevant structural member at low costs.
A high-ductility pipeline steel plate and a manufacturing method therefor. The steel plate consists of the following components in percentage by mass: C: 0.02-0.07%, Si: 0.02-0.15%, Mn: 1.30-1.90%, P: ≤0.010%, S: ≤0.0020%, Cr: 0.10-0.50%, Ni: 0.10-0.50%, Cu: 0.10-0.50％, Mo: 0.10-0.50%, Nb: 0.015-0.060%, V: 0.010-0.060%, and Alt: 0.045-0.090%, with the balance being Fe and impurities. An ultra-fine grain structure having bimodal size distribution is obtained by combining controlled rolling and controlled cooling process technologies for production, such that not only is the strength of the steel plate ensured, but the normal-temperature ductility of pipeline steel is improved, the yield-to-tensile ratio is reduced, the cold forming performance of the steel is improved, and the application range of the ultra-fine grain steel structure is broadened.
A 500 MPa grade low yield ratio weather-resistant bridge steel and manufacturing method therefor, made up of the following components by mass percentage: C: 0.04 - 0.09%, SI: 0.15 - 0.30%, Mn: 1.40 - 1.50%, P: 0.009 - 0.015%, S: ≤ 0.002%, Nb: 0.020 - 0.050%, Ti: 0.010 - 0.020%, V: 0.010 - 0.030%, Cu: 0.30 - 0.40%, Ni: 0.30 - 0.45%, Cr: 0.45 - 0.60%, Mo: 0.08 - 0.15%, Alt: 0.02 - 0.04%, and the remainder being Fe and unavoidable impurities. By means of scientific component design and matching controlled rolling/controlled cooling + tempering manufacturing methods, the weather-resistant bridge steel is imparted with the properties of low yield ratio, extreme temperature toughness, and high ductility and malleability.
Disclosed is an S355G10+N-thickness steel plate for an offshore structure, which belongs to the technical field of iron and steel smelting. The steel plate has a maximum thickness of 150 mm, and the following chemical ingredients in percentage by mass: C: 0.08%-0.14%, Mn: 1.30%-1.65%, Si: 0.10%-0.50%, P ≤ 0.015%, S ≤ 0.005%, Nb: 0.015%-0.030%, V ≤ 0.03%, Ti: 0.020%-0.10%, Alt: 0.020%-0.055%, Ni: 0.10%-0.50%, CEV ≤ 0.43%, Pcm ≤ 0.21%, and the balance being Fe and inevitable impurities. An extra thick steel plate of 150 mm has excellent low-temperature toughness, especially for an impact of greater than 100 J at a thickness of 1/2 at -40ºC, and a good welding performance, and better meets the use and service requirements of offshore structures.
Disclosed are a 690 MPa-grade medium manganese steel medium thick steel with a high strength and a low yield ratio and a manufacturing method therefor. The chemical ingredients of the medium manganese steel medium thick steel and percentages by mass thereof are as follows: C: 0.05%-0.10%, Mn: 4.1%-4.7%, Si: 0.15%-0.4%, P ≤ 0.010%, S ≤ 0.003%, Ti: 0.01%-0.05%, Ni+Cr+Mo ≤ 0.6%, and the balance being Fe and inevitable impurities. The medium manganese steel medium thick steel can meet the requirements for safety performance and construction cost of an ultra-high-strength steel in complex environments in the field of engineering machinery.
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