CPC Class Not Allocatable
C21 METALLURGY OF IRON
Description
C21 encompasses the extraction, processing, and refining of iron from ores and scrap materials, including pig iron production, steel manufacture, and cast iron processing. This class covers blast furnace operations, steelmaking processes (such as open hearth, electric arc, and oxygen conversion methods), and heat treatment of iron-based materials. It also includes surface treatment, mechanical working, and quality control of iron and iron alloys, but excludes non-ferrous metallurgy and the detailed composition or properties of specific steel grades, which are covered by materials science classifications.
3 direct subcodes
Child Classifications
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- C21B MANUFACTURE OF IRON OR STEEL (preliminary treatment of ferrous ores or scrap C22B1/00; electric heating H05B)
- C21C PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS (refining metals in general C22B9/00)
- C21D 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 (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
Top Applicants
Top 10 applicants by patent filings, 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