C21B MANUFACTURE OF IRON OR STEEL (preliminary treatment of ferrous ores or scrap C22B1/00; electric heating H05B)
Introduced: September 1968
Description
C21B covers the production processes and technologies for manufacturing iron and steel, including ore reduction, pig iron production, and steel-making methods. The subclass encompasses both traditional and modern techniques such as blast furnace operation, direct reduction processes, electric arc furnace steelmaking, and oxygen converter steelmaking. It includes related aspects of heat treatment, casting, and refining of steel products during manufacture. Adjacent class C21C addresses the processing and treatment of steel after initial manufacture, while C21B focuses on the primary conversion and formation stages from raw materials to finished steel products.
Title
Titles differ between systems:
IPC: MANUFACTURE OF IRON OR STEEL
CPC: MANUFACTURE OF IRON OR STEEL (preliminary treatment of ferrous ores or scrap C22B1/00; electric heating H05B)
Full Title
Full titles differ between systems:
MANUFACTURE OF IRON OR STEEL
MANUFACTURE OF IRON OR STEEL (preliminary treatment of ferrous ores or scrap C22B1/00; electric heating H05B)
Additional Content IPC
Glossary
Pig iron intermediate product of smelting iron ore with a high-carbon fuel, e.g. coke, charcoal Slag partially vitreous by-product of smelting ore to separate the metal fraction form the unwanted faction Tuyères tubes, nozzles or pipes through which air is blown into a furnace
Limiting references
Preliminary treatment of ferrous ores or scrap Constructional features of mixers for pig-iron Electrolytic production, recovery or refining of iron group metals
Of 11 combined children, 7 exist in both systems.
4 codes are CPC-only extensions.
Note: 4 CPC extensions are marked as secondary classification only.
3 shared codes have differing titles between IPC and CPC.
Child Classifications
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- C21B 13/00 Making spongy iron or liquid steel, by direct processes +9 CPC IPC+CPC Available in IPC and CPC
- C21B 15/00 Other processes for the manufacture of iron from iron compounds (general methods of reducing to metal C22B5/00; by electrolysis C25C1/06) +2 CPC IPC+CPC Available in IPC and CPC
- C21B 2100/00 Handling of exhaust gases produced during the manufacture of iron or steel 2nd only +4 CPC CPC only CPC only
- C21B 2400/00 Treatment of slags originating from iron or steel processes 2nd only +4 CPC CPC only CPC only
- C21B 3/00 General features in the manufacture of pig-iron (mixers for pig-iron C21C1/06) IPC+CPC Available in IPC and CPC
- C21B 7/00 Blast furnaces (lifts associated with blast furnaces B66B9/06) +2 CPC IPC+CPC Available in IPC and CPC
Top Applicants
Top Applicants (IPC)
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
Top Applicants (CPC)
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