Abstract

The invention provides a method for reducing content of MnS inclusions in steel, including: (1) placing raw materials of other elements than manganese in a smelting furnace according to components of steel to perform smelting to obtain liquid steel; (2) first adding a first rare earth element and sulfur to the liquid steel, to form rare earth sulphide, then adding a raw material containing manganese to perform smelting, performing tapping after smelting is completed, and performing pouring and cooling to obtain a cast ingot. A rare earth element and sulfur are first added to liquid steel before manganese is added to generate tiny, round rare earth sulphide, and subsequently manganese is added to make it difficult to generate MnS, so that MnS and rare earth/manganese/sulfur composite inclusions are reduced, and content of MnS inclusions at a parting plane of a workpiece is reduced, thereby improving the reliability of the workpiece.

IPC Classes  ?

• C21C 7/00 - Treating molten ferrous alloys, e.g. steel, not covered by groups
• C21C 7/10 - Handling in vacuum

Abstract

The invention provides a method for increasing wear resistance of a surface of a crankshaft, including: dividing a journal of a crankshaft into a journal coating portion and two journal grinding portions located on two sides of the journal coating portion; the surface of the journal grinding portion is higher than that of the journal coating portion, and higher than the surface of the journal of a finished crankshaft, the surface of the rounded corner of the crankshaft is higher than that of the rounded corner of the finished crankshaft, and the size of the journal coating portion is smaller than that of the journal of the finished crankshaft; and spraying a ceramic coating on the surface of the journal coating portion, grinding the surfaces of the journal and the rounded corner until the ceramic coating and the surface of the rounded corner are seamlessly joined, and performing polishing.

IPC Classes  ?

• C23C 24/08 - Coating starting from inorganic powder by application of heat or pressure and heat

Abstract

The present disclosure provides a method for controlling an amount of silicon added to ductile cast iron, a method for casting ductile cast iron, and a cast product, which relate to the technical fields of metallurgical and cast iron alloys. The method for controlling an amount of silicon added to ductile cast iron includes smelting ductile cast iron using scrap steel as a raw material. After the scrap steel is melted into molten iron, a copper alloy is added so that the molten iron has a copper equivalent of 0.8% to 1.0%, wherein the copper equivalent is controlled by formula (II). Then, ferrosilicon is added so that the content of silicon added to the molten iron satisfies formula (I).

IPC Classes  ?

• C22C 37/10 - Cast-iron alloys containing aluminium or silicon
• C21C 1/10 - Making spheroidal graphite cast-iron
• C21D 1/28 - Normalising
• C21D 1/32 - Soft annealing, e.g. spheroidising
• C21D 5/14 - Graphitising
• C22C 37/04 - Cast-iron alloys containing spheroidal graphite

Abstract

The present application relates to the technical field of metallurgy and cast iron alloys, and provides an addition control method for the silicon content in ductile iron, a ductile iron casting method, and a casting. The addition control method for the silicon content in ductile iron comprises: smelting ductile iron by using scrap steel as a raw material, after melting to molten iron, first adding copper alloy to enable the copper equivalent in the molten iron to be 0.8-1.0%, the copper equivalent control formula being formula (II), and then adding ferrosilicon to enable the silicon content added in the molten iron to meet formula (I). By dynamically regulating the silicon content, the present application solves the problem of ductile iron having high tensile strength but low notch impact toughness, or high notch impact toughness but low tensile strength. A casting obtained by the method in the present application has the body tensile strength greater than or equal to 900 MPa, elongation greater than or equal to 7%, and notch impact energy at room temperature greater than or equal to 7 J, and can be applied to connecting rod production.

IPC Classes  ?

• C21C 1/10 - Making spheroidal graphite cast-iron
• C22C 33/08 - Making cast-iron alloys
• C21D 5/00 - Heat treatment of cast-iron
• C21D 1/28 - Normalising

Abstract

2. The present invention overcomes the technical problem that existing steel connecting rods have larger weights.

IPC Classes  ?

• F16C 7/00 - Connecting-rods or like links pivoted at both endsConstruction of connecting-rod heads
• F16C 7/08 - Connecting-rods or like links pivoted at both endsConstruction of connecting-rod heads made from sheet metal

Goods & Services

Crankshafts; internal combustion engine parts.

Goods & Services

Crankshafts for automobile engines; internal combustion engine parts, namely, pistons, heads