- 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 9/02 - Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor for springs
Patent holdings for IPC class C21D 9/02
Total number of patents in this class: 240
10-year publication summary
|
18
|
22
|
19
|
19
|
13
|
15
|
12
|
8
|
11
|
3
|
| 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
Principal owners for this class
| Owner |
All patents
|
This class
|
|---|---|---|
| NHK Spring Co., Ltd. | 1858 |
63 |
| Nippon Steel Corporation | 6231 |
15 |
| Chuo Hatsujo Kabushiki Kaisha | 128 |
12 |
| Sumitomo Electric Industries, Ltd. | 15455 |
11 |
| Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) | 2875 |
9 |
| Nippon Steel SG Wire Co., Ltd. | 14 |
8 |
| JFE Steel Corporation | 6833 |
5 |
| POSCO Co., Ltd. | 1564 |
5 |
| ArcelorMittal | 2280 |
4 |
| Mitsubishi Steel Mfg. Co., Ltd. | 129 |
4 |
| NV Bekaert SA | 746 |
4 |
| ThyssenKrupp AG | 3281 |
4 |
| ThyssenKrupp Federn und Stabilisatoren GmbH | 49 |
4 |
| Nivarox-FAR S.A. | 281 |
3 |
| Radyne Corporation | 40 |
3 |
| Sumitomo (SEI) Steel Wire Corp. | 43 |
3 |
| Voestalpine Precision Strip AB | 21 |
3 |
| General Electric Company | 13767 |
2 |
| Hyundai Motor Company | 21960 |
2 |
| Baoshan Iron & Steel Co., Ltd. | 962 |
2 |
| Other owners | 74 |