Skip to content
PCE
Search Classifications
Search for IPC and CPC classification codes or keywords
DIFF Subgroup
C21D 1/20

Isothermal quenching, e.g. bainitic hardening

Introduced: September 1968

Full Title

Full titles differ between systems:

IPC:

General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering > Hardening; Quenching with or without subsequent tempering > by interrupted quenching > Isothermal quenching, e.g. bainitic hardening

CPC:

General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering > Hardening (C21D1/02 takes precedence); Quenching with or without subsequent tempering (quenching devices C21D1/62) > by interrupted quenching > Isothermal quenching, e.g. bainitic hardening

No child classifications to compare. This is a leaf node in both 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