CPC Subgroup
C21D 1/63 for bath quenching
Full Title
General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering > Quenching devices > for bath quenching
1 direct subcode
Child Classifications
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- C21D 1/64 with circulating liquids
Top Applicants
Top 10 applicants by patent filingsfor class C21, 2013–2023, worldwide · Source: EPO PATSTAT
- JFE STEEL JP 8,270
- NIPPON STEEL CORPORATION JP 5,222
- POSCO (POHANG IRON AND STEEL COMPANY) KR 4,824
- JFE STEEL 3,311
- ARCELORMITTAL LU 3,239
- NSSMC (NIPPON STEEL & SUMITOMO METAL) JP 2,659
- HYUNDAI STEEL COMPANY KR 1,492
- ANGANG STEEL COMPANY 1,318
- BAOSHAN IRON & STEEL COMPANY 1,233
- KOBE STEEL JP 1,228