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PCE
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DIFF Subgroup
C21D 1/26

Methods of annealing

Introduced: September 1968

Full Title

General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering > Methods of annealing

IPC and CPC are identically structured here. All 3 subcodes exist in both systems.

Child Classifications

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  • C21D 1/28 Normalising IPC+CPC Available in IPC and CPC
  • C21D 1/30 Stress-relieving IPC+CPC Available in IPC and CPC
  • C21D 1/32 Soft annealing, e.g. spheroidising IPC+CPC Available in IPC and CPC

Top Applicants

Top Applicants (IPC)

Class C21,2013–2023, worldwide · Source: EPO PATSTAT

  1. JFE STEEL JP 7,470
  2. POSCO (POHANG IRON AND STEEL COMPANY) KR 4,615
  3. JFE STEEL 4,538
  4. NIPPON STEEL CORPORATION JP 4,536
  5. ARCELORMITTAL LU 2,597
  6. NSSMC (NIPPON STEEL & SUMITOMO METAL) JP 2,241
  7. ANGANG STEEL COMPANY 2,126
  8. NSSMC (NIPPON STEEL & SUMITOMO METAL) 1,783
  9. BAOSHAN IRON & STEEL COMPANY 1,620
  10. HYUNDAI STEEL COMPANY KR 1,545

Top Applicants (CPC)

Class C21,2013–2023, worldwide · Source: EPO PATSTAT

  1. JFE STEEL JP 8,270
  2. NIPPON STEEL CORPORATION JP 5,222
  3. POSCO (POHANG IRON AND STEEL COMPANY) KR 4,824
  4. JFE STEEL 3,311
  5. ARCELORMITTAL LU 3,239
  6. NSSMC (NIPPON STEEL & SUMITOMO METAL) JP 2,659
  7. HYUNDAI STEEL COMPANY KR 1,492
  8. ANGANG STEEL COMPANY 1,318
  9. BAOSHAN IRON & STEEL COMPANY 1,233
  10. KOBE STEEL JP 1,228