C21D 1/00
General methods or devices for heat treatment
Official title: General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
C21D1/00 (General methods or devices for heat treatment) appears on 6,542 US grants and 7,726 published applications in this corpus.
Search patents in C21D- Granted patents
- 6,542
- Published applications
- 7,726
- Assignees
- 2,423
- Inventors
- 14,669
- Latest grant
- 6 Oct 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 73 | 0 |
| 1977 | 58 | 0 |
| 1978 | 58 | 0 |
| 1979 | 47 | 0 |
| 1980 | 70 | 0 |
| 1981 | 45 | 0 |
| 1982 | 42 | 0 |
| 1983 | 69 | 0 |
| 1984 | 54 | 0 |
| 1985 | 64 | 0 |
| 1986 | 70 | 0 |
| 1987 | 48 | 0 |
| 1988 | 53 | 0 |
| 1989 | 79 | 0 |
| 1990 | 57 | 0 |
| 1991 | 56 | 0 |
| 1992 | 52 | 0 |
| 1993 | 64 | 0 |
| 1994 | 84 | 0 |
| 1995 | 74 | 0 |
| 1996 | 69 | 0 |
| 1997 | 71 | 0 |
| 1998 | 83 | 0 |
| 1999 | 92 | 0 |
| 2000 | 98 | 0 |
| 2001 | 115 | 29 |
| 2002 | 96 | 96 |
| 2003 | 92 | 108 |
| 2004 | 87 | 136 |
| 2005 | 62 | 100 |
| 2006 | 56 | 129 |
| 2007 | 52 | 126 |
| 2008 | 54 | 123 |
| 2009 | 66 | 189 |
| 2010 | 89 | 205 |
| 2011 | 86 | 220 |
| 2012 | 112 | 237 |
| 2013 | 140 | 259 |
| 2014 | 149 | 313 |
| 2015 | 173 | 415 |
| 2016 | 212 | 511 |
| 2017 | 272 | 421 |
| 2018 | 309 | 402 |
| 2019 | 386 | 433 |
| 2020 | 320 | 409 |
| 2021 | 314 | 384 |
| 2022 | 336 | 559 |
| 2023 | 280 | 534 |
| 2024 | 348 | 574 |
| 2025 | 438 | 442 |
| 2026 | 268 | 372 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
- C21D 1/18Hardening1,959
- C21D 1/26Methods of annealing1,209
- C21D 1/62Quenching devices1,182
- C21D 1/34Methods of heating1,173
- C21D 1/74Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material1,158
- C21D 1/06Surface hardening994
- C21D 1/56General methods or devices for heat treatment: characterised by the quenching agents578
- C21D 1/84Controlled slow cooling198
All 15 subgroupsShow fewer
- C21D 1/68Temporary coatings or embedding materials applied before or during heat treatment197
- C21D 1/78Combined heat-treatments not provided for above193
- C21D 1/02Hardening articles or materials formed by forging or rolling, with no further180
- C21D 1/04General methods or devices for heat treatment: with simultaneous application of supersonic162
- C21D 1/55Hardenability tests18
- C21D 1/54Determining when the hardening temperature has been reached by measurement of magnetic12
- C21D 1/82Descaling by thermal stresses11
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
- Workpiece holding device6 Oct 2026US 12,753,453 B2Aktiebolaget Skf
- Ultra-high strength cold rolled steel sheet having excellent bendability, and method of manufacturing same6 Oct 2026US 12,753,455 B2Posco
- Annealing separator composition for grain- oriented electrical steel sheet, grain-oriented electrical steel sheet, and method for producing grain-oriented electrical steel sheet6 Oct 2026US 12,753,457 B2Posco
- Blank, production method for structural member and structural member8 Oct 2026US 2026/0307133 A1Nippon Steel Corporation
- Blank, production method for structural member and structural member1 Oct 2026US 2026/0296583 A1Nippon Steel Corporation
- Method and device for rapidly cooling a metal strip and continuous production line for metal strips1 Oct 2026US 2026/0297700 A1Fives Stein
- Temperature-control device1 Oct 2026US 2026/0297702 A1EBNER Industrieofenbau GmbH
- Coated steel sheet, member, and methods for producing the same1 Oct 2026US 2026/0297713 A1Jfe Steel Corporation
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
- Hydrogen annealing process and apparatus therefor428US 6,527,884 B1Hitachi Kokusai Electric Inc. · 2003
- Double wall fast cool-down furnace366US 4,802,441 ABTU Engineering Corporation · 1989
- In-situ generation of heat treating atmospheres using non-cryogenically produced nitrogen320US 5,298,089 AAir Products and Chemicals, Inc. · 1994