C21D 6/04
Hardening by cooling below 0 degrees celsius
Official title: Hardening by cooling below 0 degrees Celsius
C21D6/04 (Hardening by cooling below 0 degrees celsius) appears on 149 US grants and 159 published applications in this corpus.
Search patents in C21D- Granted patents
- 149
- Published applications
- 159
- Assignees
- 132
- Inventors
- 381
- Latest grant
- 25 Aug 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1982 | 1 | 0 |
| 1983 | 0 | 0 |
| 1984 | 1 | 0 |
| 1985 | 0 | 0 |
| 1986 | 0 | 0 |
| 1987 | 0 | 0 |
| 1988 | 0 | 0 |
| 1989 | 2 | 0 |
| 1990 | 0 | 0 |
| 1991 | 3 | 0 |
| 1992 | 3 | 0 |
| 1993 | 3 | 0 |
| 1994 | 2 | 0 |
| 1995 | 4 | 0 |
| 1996 | 1 | 0 |
| 1997 | 1 | 0 |
| 1998 | 2 | 0 |
| 1999 | 4 | 0 |
| 2000 | 4 | 0 |
| 2001 | 4 | 2 |
| 2002 | 13 | 8 |
| 2003 | 7 | 6 |
| 2004 | 8 | 5 |
| 2005 | 0 | 3 |
| 2006 | 1 | 2 |
| 2007 | 4 | 3 |
| 2008 | 4 | 3 |
| 2009 | 1 | 10 |
| 2010 | 2 | 10 |
| 2011 | 4 | 5 |
| 2012 | 7 | 4 |
| 2013 | 3 | 3 |
| 2014 | 5 | 5 |
| 2015 | 3 | 5 |
| 2016 | 2 | 11 |
| 2017 | 2 | 5 |
| 2018 | 5 | 6 |
| 2019 | 11 | 9 |
| 2020 | 2 | 5 |
| 2021 | 3 | 10 |
| 2022 | 4 | 9 |
| 2023 | 5 | 9 |
| 2024 | 5 | 11 |
| 2025 | 8 | 6 |
| 2026 | 5 | 4 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
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Most cited
By later US patents
- Heat management drilling system and method51US 6,374,932 B12002
- Case carburized stainless steel alloy for high temperature applications26US 5,424,028 ALatrobe Steel Company · 1995
- Secondary-hardening gear steel26US 8,801,872 B2QuesTek Innovations LLC · 2014
- Razor blade steel having high corrosion resistance and differential residual austenite content23US 5,275,672 AHitachi Metals, Ltd. · 1994
- Rolling bearing23US 5,873,956 ANsk Ltd. · 1999