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DIFF Subclass Not Allocatable
B21H

MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS (essentially from sheet metal B21D)

Introduced: September 1968

Description

B21H encompasses mechanical metal-working processes that form specific finished metal articles or near-finished components through rolling operations, without material removal. The subclass covers techniques for manufacturing discrete objects such as screws, wheels, rings, barrels, balls, and similar items where rolling is the primary shaping method. This includes cold rolling, hot rolling, and thread rolling processes applied to achieve dimensional accuracy and desired material properties in the final product. Related forming operations are classified elsewhere—B21B covers flat-rolled products (strip, sheet, plate), while B21G addresses other metal-working methods like forging and bending.

Title

Titles differ between systems:

IPC: MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS

CPC: MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS (essentially from sheet metal B21D)

Full Title

Full titles differ between systems:

IPC:

MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS

CPC:

MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS (essentially from sheet metal B21D)

IPC and CPC are identically structured here. All 6 subcodes exist in both systems.

3 shared codes have differing titles between IPC and CPC.

Child Classifications

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Top Applicants

Top Applicants (IPC)

Class B21,2013–2023, worldwide · Source: EPO PATSTAT

  1. JFE STEEL 2,318
  2. JFE STEEL JP 2,294
  3. POSCO (POHANG IRON AND STEEL COMPANY) KR 2,083
  4. NIPPON STEEL CORPORATION JP 1,650
  5. NSSMC (NIPPON STEEL & SUMITOMO METAL) JP 1,631
  6. SMS GROUP DE 1,472
  7. BAOSHAN IRON & STEEL COMPANY 1,181
  8. SGCC(STATE GRID CORPORATION OF CHINA) 1,079
  9. ANHUI JIANGHUAI AUTOMOBILE 984
  10. HYUNDAI STEEL COMPANY KR 980

Top Applicants (CPC)

Class B21,2013–2023, worldwide · Source: EPO PATSTAT

  1. JFE STEEL JP 2,667
  2. NIPPON STEEL CORPORATION JP 2,049
  3. POSCO (POHANG IRON AND STEEL COMPANY) KR 1,967
  4. NSSMC (NIPPON STEEL & SUMITOMO METAL) JP 1,800
  5. SMS GROUP DE 1,538
  6. JFE STEEL 1,150
  7. ARCELORMITTAL LU 1,142
  8. BAOSHAN IRON & STEEL COMPANY 821
  9. HYUNDAI STEEL COMPANY KR 808
  10. THYSSENKRUPP STEEL EUROPE DE 660