440C Stainless

UNS S44004 stainless
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High-carbon martensitic stainless steel with the highest hardness of the 440-series. Used in bearings, cutting instruments, and valve components requiring high wear resistance.

Applicable Standards

  • ASTM A276
  • AMS 5630
  • UNS S44004

Composition Ranges (wt %)

Element Min (%) Max (%) Typical Range
Fe 78.0 82.0 ~80.0
Cr 16.0 18.0 ~17.0
C 0.95 1.2 ~1.07
Mo — 0.75 ~0.38
Mn — 1.0 ~0.5
Si — 1.0 ~0.5
Fe 78.0–82.0% Cr 16.0–18.0% C 0.95–1.2% Mo 0.0–0.75% Mn 0.0–1.0% Si 0.0–1.0%

Typical Applications

  • Ball bearings
  • Surgical blades
  • Valve seats
  • Cutlery
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