C21
Metallurgy of iron
C21 (Metallurgy of iron) appears on 21,390 US grants and 18,906 published applications in this corpus.
Search patents in C21- Granted patents
- 21,390
- Published applications
- 18,906
- Assignees
- 5,967
- Inventors
- 38,083
- Latest grant
- 6 Oct 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 394 | 0 |
| 1977 | 407 | 0 |
| 1978 | 379 | 0 |
| 1979 | 305 | 0 |
| 1980 | 373 | 0 |
| 1981 | 343 | 0 |
| 1982 | 318 | 0 |
| 1983 | 411 | 0 |
| 1984 | 366 | 0 |
| 1985 | 348 | 0 |
| 1986 | 349 | 0 |
| 1987 | 326 | 0 |
| 1988 | 345 | 0 |
| 1989 | 354 | 0 |
| 1990 | 316 | 0 |
| 1991 | 297 | 0 |
| 1992 | 266 | 0 |
| 1993 | 295 | 0 |
| 1994 | 303 | 0 |
| 1995 | 305 | 0 |
| 1996 | 306 | 0 |
| 1997 | 277 | 0 |
| 1998 | 332 | 0 |
| 1999 | 380 | 0 |
| 2000 | 393 | 0 |
| 2001 | 488 | 115 |
| 2002 | 437 | 360 |
| 2003 | 420 | 422 |
| 2004 | 318 | 470 |
| 2005 | 221 | 328 |
| 2006 | 168 | 399 |
| 2007 | 165 | 391 |
| 2008 | 169 | 442 |
| 2009 | 236 | 586 |
| 2010 | 313 | 650 |
| 2011 | 336 | 627 |
| 2012 | 393 | 689 |
| 2013 | 427 | 753 |
| 2014 | 452 | 859 |
| 2015 | 499 | 992 |
| 2016 | 555 | 1046 |
| 2017 | 691 | 981 |
| 2018 | 686 | 985 |
| 2019 | 834 | 1026 |
| 2020 | 789 | 987 |
| 2021 | 716 | 919 |
| 2022 | 804 | 1103 |
| 2023 | 687 | 1045 |
| 2024 | 720 | 1063 |
| 2025 | 813 | 867 |
| 2026 | 565 | 801 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subclasses
Granted patents
Recent patents
- Housing of an induction hardening tool6 Oct 2026US 12,752,288 B2Aktiebolaget Skf
- Forged steel roll for cold rolling6 Oct 2026US 12,752,325 B2Nippon Steel Corporation
- Method for manufacturing direct reduced iron and DRI manufacturing equipment6 Oct 2026US 12,753,452 B2ArcelorMittal
- Workpiece holding device6 Oct 2026US 12,753,453 B2Aktiebolaget Skf
- High strength steel sheet and method of producing same6 Oct 2026US 12,753,454 B2Jfe Steel Corporation
- Blank, production method for structural member and structural member8 Oct 2026US 2026/0307133 A1Nippon Steel Corporation
- Reoxidation retardant and method for hindering reoxidation of direct reduced iron8 Oct 2026US 2026/0308704 A1
- Method of producing reduced iron8 Oct 2026US 2026/0308705 A1Jfe Steel Corporation
- A cold rolled martensitic steel and a method of martensitic steel thereof8 Oct 2026US 2026/0308706 A1
- Non-oriented electrical steel plate with high magnetic induction and manufacturing method thereof8 Oct 2026US 2026/0308707 A1Baoshan Iron & Steel Co., Ltd.
Most cited
By later US patents
- Method for annealing stapler anvils1,469US 5,173,133 AUnited States Surgical Corporation · 1992
- Surface hardening of cams of motor-vehicle camshafts1,402US 4,312,685 AAudi NSU Auto Union Aktiengesellschaft · 1982
- Systems for percutaneous bone and spinal stabilization, fixation and repair1,069US 6,127,597 ADiscoTech N.V. · 2000
- Probe for taking gas samples and heat measurements in a shaft furnace485US 5,108,192 APaul Wurth S. A. · 1992
- Method of making iron golf clubs with flexible impact surface459US 4,398,965 APepsiCo, Inc. · 1983