C21D 9/28
Heat treatment: for plain shafts
Official title: for plain shafts
C21D9/28 (Heat treatment: for plain shafts) appears on 118 US grants and 156 published applications in this corpus.
Search patents in C21D- Granted patents
- 118
- Published applications
- 156
- Assignees
- 112
- Inventors
- 409
- Latest grant
- 1 Sep 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 2 | 0 |
| 1977 | 0 | 0 |
| 1978 | 0 | 0 |
| 1979 | 1 | 0 |
| 1980 | 1 | 0 |
| 1981 | 1 | 0 |
| 1982 | 1 | 0 |
| 1983 | 0 | 0 |
| 1984 | 0 | 0 |
| 1985 | 0 | 0 |
| 1986 | 0 | 0 |
| 1987 | 0 | 0 |
| 1988 | 2 | 0 |
| 1989 | 2 | 0 |
| 1990 | 1 | 0 |
| 1991 | 1 | 0 |
| 1992 | 2 | 0 |
| 1993 | 0 | 0 |
| 1994 | 0 | 0 |
| 1995 | 2 | 0 |
| 1996 | 1 | 0 |
| 1997 | 0 | 0 |
| 1998 | 0 | 0 |
| 1999 | 1 | 0 |
| 2000 | 1 | 0 |
| 2001 | 2 | 1 |
| 2002 | 3 | 2 |
| 2003 | 1 | 0 |
| 2004 | 1 | 2 |
| 2005 | 1 | 3 |
| 2006 | 2 | 6 |
| 2007 | 1 | 8 |
| 2008 | 3 | 7 |
| 2009 | 4 | 10 |
| 2010 | 2 | 7 |
| 2011 | 2 | 9 |
| 2012 | 4 | 11 |
| 2013 | 3 | 5 |
| 2014 | 8 | 6 |
| 2015 | 7 | 6 |
| 2016 | 6 | 10 |
| 2017 | 6 | 7 |
| 2018 | 6 | 7 |
| 2019 | 6 | 7 |
| 2020 | 4 | 5 |
| 2021 | 7 | 8 |
| 2022 | 4 | 6 |
| 2023 | 2 | 6 |
| 2024 | 6 | 7 |
| 2025 | 5 | 8 |
| 2026 | 3 | 2 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Surface-hardened, rotationally symmetrical workpiece, hardening method and hardening apparatus1 Sep 2026US 12,723,286 B2Walzengiesserei Coswig GmbH
- Hollow wind turbine main shaft and profiling forging process and use thereof25 Aug 2026US 12,716,108 B2Zenkung Heavy Industry (Jiangsu) Co., Ltd.
- Bearing part10 Mar 2026US 12,571,427 B2Ntn Corporation
- Railway axle5 Aug 2025US 12,377,888 B2Nippon Steel Corporation
- Alloy5 Aug 2025US 12,378,648 B2Nippon Steel Corporation
- Railway axle30 Jul 2026US 2026/0218349 A1Nippon Steel Corporation
- Hollow wind turbine main shaft and profiling forging process and use thereof30 Apr 2026US 2026/0117334 A1Zenkung Heavy Industry (Jiangsu) Co., Ltd.
- Traverse hardening device23 Oct 2025US 2025/0327144 A1Nippon Steel Corporation
- Traverse hardening device and traverse hardening method9 Oct 2025US 2025/0318020 A1Nippon Steel Corporation
- Hydrogen recycling unit for high pressure gas quenching7 Aug 2025US 2025/0250650 A1L Air Liquide, Societe Anonyme Pour L'Etude et L'Exploitation des Procedes Georges Claude
Most cited
By later US patents
- Method of working metal, metal body obtained by the method and metal-containing ceramic body obtained by the method46US 7,559,221 B2Rinascimetalli Ltd. · 2009
- Warm forming high strength steel parts42US 5,538,566 AConsolidated Metal Products, Inc. · 1996
- Turbine rotor23US 4,778,345 ANgk Spark Plug Co., Ltd. · 1988
- High strength low alloyed sintered steel19US 8,702,835 B2HöGanäS AB (Publ) · 2014
- Steel torsional element and method for making17US 4,173,501 AClark Equipment Company · 1979