IPC Subgroup
C21D 3/1 Furnaces therefor
Introduced: September 1968
Last revised: January 2006
Full Title
Diffusion processes for extraction of non-metals; Furnaces therefor > Furnaces therefor
Classification Context
- Section:
- CHEMISTRY; METALLURGY
- Class:
- METALLURGY OF IRON
- Subclass:
- MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
Top Applicants
Top 10 applicants by patent filingsfor class C21, 2013–2023, worldwide · Source: EPO PATSTAT
- JFE STEEL JP 7,470
- POSCO (POHANG IRON AND STEEL COMPANY) KR 4,615
- JFE STEEL 4,538
- NIPPON STEEL CORPORATION JP 4,536
- ARCELORMITTAL LU 2,597
- NSSMC (NIPPON STEEL & SUMITOMO METAL) JP 2,241
- ANGANG STEEL COMPANY 2,126
- NSSMC (NIPPON STEEL & SUMITOMO METAL) 1,783
- BAOSHAN IRON & STEEL COMPANY 1,620
- HYUNDAI STEEL COMPANY KR 1,545