C21D 9/02
Heat treatment: for springs
Official title: for springs
C21D9/02 (Heat treatment: for springs) appears on 195 US grants and 206 published applications in this corpus.
Search patents in C21D- Granted patents
- 195
- Published applications
- 206
- Assignees
- 138
- Inventors
- 550
- Latest grant
- 22 Sep 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 3 | 0 |
| 1977 | 1 | 0 |
| 1978 | 0 | 0 |
| 1979 | 2 | 0 |
| 1980 | 3 | 0 |
| 1981 | 2 | 0 |
| 1982 | 0 | 0 |
| 1983 | 0 | 0 |
| 1984 | 0 | 0 |
| 1985 | 2 | 0 |
| 1986 | 1 | 0 |
| 1987 | 1 | 0 |
| 1988 | 2 | 0 |
| 1989 | 2 | 0 |
| 1990 | 2 | 0 |
| 1991 | 1 | 0 |
| 1992 | 3 | 0 |
| 1993 | 9 | 0 |
| 1994 | 5 | 0 |
| 1995 | 3 | 0 |
| 1996 | 6 | 0 |
| 1997 | 2 | 0 |
| 1998 | 5 | 0 |
| 1999 | 4 | 0 |
| 2000 | 5 | 0 |
| 2001 | 6 | 0 |
| 2002 | 5 | 2 |
| 2003 | 2 | 3 |
| 2004 | 1 | 4 |
| 2005 | 1 | 5 |
| 2006 | 2 | 6 |
| 2007 | 1 | 5 |
| 2008 | 3 | 6 |
| 2009 | 1 | 9 |
| 2010 | 4 | 11 |
| 2011 | 6 | 5 |
| 2012 | 3 | 12 |
| 2013 | 7 | 12 |
| 2014 | 8 | 9 |
| 2015 | 6 | 12 |
| 2016 | 8 | 7 |
| 2017 | 9 | 20 |
| 2018 | 5 | 11 |
| 2019 | 9 | 17 |
| 2020 | 13 | 8 |
| 2021 | 8 | 8 |
| 2022 | 5 | 7 |
| 2023 | 5 | 7 |
| 2024 | 6 | 11 |
| 2025 | 4 | 5 |
| 2026 | 3 | 4 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Wire rod and steel wire for high strength spring, and manufacturing method therefor22 Sep 2026US 12,742,220 B2Posco
- Steel wire28 Apr 2026US 12,612,675 B2Nippon Steel Corporation
- Method of heat-treating additively manufactured ferromagnetic components7 Apr 2026US 12,597,811 B2General Electric Company
- Wire rod and steel wire for spring, having enhanced toughness and corrosion fatigue properties, and respective manufacturing methods therefor5 Aug 2025US 12,378,628 B2Posco
- Damper spring24 Jun 2025US 12,338,516 B2Nippon Steel Corporation
- Forged part of steel and a method of manufacturing thereof3 Sep 2026US 2026/0258537 A1
- Method of heat-treating additively manufactured ferromagnetic components16 Jul 2026US 2026/0204957 A1General Electric Company
- Coil spring manufacturing method12 Feb 2026US 2026/0042138 A1NHK Spring Co., Ltd.
- Manufacturing method of stabilizer and stabilizer22 Jan 2026US 2026/0022432 A1NHK Spring Co., Ltd.
- Fe-mn alloy, hairspring for timepiece, and method for producing fe-mn alloy16 Oct 2025US 2025/0320585 A1Citizen Watch Co., Ltd.
Most cited
By later US patents
- Method of manufacturing a car stabilizer45US 4,526,628 ANHK Spring Co., Ltd. · 1985
- Warm forming high strength steel parts42US 5,538,566 AConsolidated Metal Products, Inc. · 1996
- Method for selectively forming (plastic working) at least one region of a sheet metal layer made from a sheet of spring steel, and a device for carrying out this method33US 8,336,359 B2ElringKlinger AG · 2012
- Surface treatment method for a steel workpiece using high speed shot peening24US 5,816,088 AKabushiki Kaisha Fuji Seisakusho · 1998
- Highly strengthened spring and process for producing the same21US 6,544,360 B1NHK Spring Co., Ltd. · 2003