MANUFACTURE OF IRON OR STEEL

Introduced: September 1968

Classification Context

Section:: CHEMISTRY; METALLURGY
Class:: METALLURGY OF IRON
Subclass:: MANUFACTURE OF IRON OR STEEL

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.

Additional Content

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

Related Keywords

production of IRON or steelobtaining METAL COMPOUNDS by metallurgical methodstreating ORES to obtain ironREFINING of ironsmelting STOVES

7 direct subcodes

Child Classifications

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C21B 11/00 Making pig-iron other than in blast furnaces
C21B 13/00 Making spongy iron or liquid steel, by direct processes
C21B 15/00 Other processes for the manufacture of iron from iron compounds
C21B 3/00 General features in the manufacture of pig-iron
C21B 5/00 Making pig-iron in the blast furnace
C21B 7/00 Blast furnaces
C21B 9/00 Stoves for heating the blast in blast furnaces

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