- All sections
- C - Chemistrymetallurgy
- C21D - Modifying the physical structure of ferrous metalsgeneral devices for heat treatment of ferrous or non-ferrous metals or alloysmaking metal malleable, e.g. by decarburisation or tempering
- C21D 9/28 - Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor for plain shafts
Patent holdings for IPC class C21D 9/28
Total number of patents in this class: 156
10-year publication summary
|
13
|
11
|
17
|
5
|
6
|
9
|
9
|
10
|
16
|
4
|
| 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 |
Principal owners for this class
| Owner |
All patents
|
This class
|
|---|---|---|
| Nippon Steel Corporation | 6895 |
34 |
| NTN Corporation | 4915 |
14 |
| ArcelorMittal | 2680 |
6 |
| Nippon Steel & Sumitomo Metal Corporation | 1981 |
6 |
| NSK Ltd. | 2832 |
4 |
| Aubert & Duval | 110 |
4 |
| Daido Steel Co., Ltd. | 284 |
4 |
| JFE Steel Corporation | 7549 |
4 |
| Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) | 2836 |
4 |
| V & M do Brasil S/A | 4 |
3 |
| Walzengießerei Coswig GmbH | 6 |
3 |
| CRS Holdings, LLC | 148 |
3 |
| Rtx Corporation | 10128 |
3 |
| Caterpillar Inc. | 10281 |
2 |
| Komatsu Ltd. | 4733 |
2 |
| Hyundai Steel Company | 535 |
2 |
| Mitsubishi Hitachi Power Systems, Ltd. | 991 |
2 |
| POSCO Co., Ltd. | 2015 |
2 |
| Beijing Huali Fine Chemical Co., Ltd. | 2 |
2 |
| Mitsubishi Power, Ltd. | 1834 |
2 |
| Other owners | 50 |