C21D 1/18
Hardening
Official title: Hardening (C21D1/02 takes precedence); Quenching with or without subsequent tempering (quenching devices C21D1/62)
C21D1/18 (Hardening) appears on 1,959 US grants and 2,993 published applications in this corpus.
Search patents in C21D- Granted patents
- 1,959
- Published applications
- 2,993
- Assignees
- 819
- Inventors
- 5,433
- Latest grant
- 6 Oct 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 4 | 0 |
| 1977 | 6 | 0 |
| 1978 | 4 | 0 |
| 1979 | 8 | 0 |
| 1980 | 7 | 0 |
| 1981 | 3 | 0 |
| 1982 | 4 | 0 |
| 1983 | 8 | 0 |
| 1984 | 5 | 0 |
| 1985 | 8 | 0 |
| 1986 | 9 | 0 |
| 1987 | 1 | 0 |
| 1988 | 3 | 0 |
| 1989 | 12 | 0 |
| 1990 | 5 | 0 |
| 1991 | 4 | 0 |
| 1992 | 4 | 0 |
| 1993 | 6 | 0 |
| 1994 | 14 | 0 |
| 1995 | 19 | 0 |
| 1996 | 13 | 0 |
| 1997 | 22 | 0 |
| 1998 | 15 | 0 |
| 1999 | 18 | 0 |
| 2000 | 23 | 0 |
| 2001 | 36 | 9 |
| 2002 | 29 | 20 |
| 2003 | 24 | 40 |
| 2004 | 25 | 45 |
| 2005 | 14 | 26 |
| 2006 | 14 | 38 |
| 2007 | 8 | 41 |
| 2008 | 9 | 33 |
| 2009 | 18 | 51 |
| 2010 | 26 | 44 |
| 2011 | 23 | 59 |
| 2012 | 32 | 66 |
| 2013 | 39 | 72 |
| 2014 | 33 | 96 |
| 2015 | 53 | 159 |
| 2016 | 61 | 162 |
| 2017 | 79 | 157 |
| 2018 | 103 | 148 |
| 2019 | 149 | 184 |
| 2020 | 102 | 158 |
| 2021 | 118 | 170 |
| 2022 | 135 | 248 |
| 2023 | 98 | 262 |
| 2024 | 163 | 285 |
| 2025 | 209 | 242 |
| 2026 | 134 | 178 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
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
- 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
- Carbide refining method of high-carbon high-alloy steel29 Sep 2026US 12,747,488 B2Shanghai Jiaotong University
- 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
- Corrosion and wear resistant alloy88US 6,702,905 B1L. E. Jones Company · 2004
- High toughness low yield ratio, high fatigue strength steel plate and process of producing same65US 5,454,883 ANippon Steel Corporation · 1995
- Method of making high strength, tough alloy steel62US 4,170,499 AThe Regents of the University of California · 1979
- Low alloy steel for oil country tubular goods and method of making57US 6,267,828 B12001
- Flat product, such as sheet, made of steel having a high yield strength and exhibiting good ductility and process for manufacturing this product53US 6,395,108 B2Recherche et Developpement du Groupe Cockerill Sambre · 2002