MANUFACTURE OF IRON OR STEEL (preliminary treatment of ferrous ores or scrap C22B1/00; electric heating H05B)

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.

Filing statistics

CPC subclass C21B recorded 18,493 patent applications worldwide between 2013 and 2023. Annual filings grew from 1,109 in 2013 to 2,100 in 2023 (+89%), peaking at 2,528 applications in 2022. The most active applicants in class C21 are JFE STEEL (8,270 applications), NIPPON STEEL CORPORATION (5,222 applications) and POSCO (POHANG IRON AND STEEL COMPANY) (4,824 applications).

Source: EPO PATSTAT, worldwide filings