Stainless Steel, Martensitic1.4125 (440C) Bar

A martensitic stainless steel with the highest carbon content in the 400 series.

440C stainless steel is a member of the 400 series of stainless steels. It has the highest carbon content among them. It is capable of attaining, after heat treatment, the highest strength, hardness and wear resistance of all the stainless alloys. Its very high carbon content is responsible for these characteristics, which make 440C particularly suited to such applications as ball bearings and valve parts.

Martensitic stainless steels are optimised for high hardness, and other properties are to some degree compromised. Fabrication must be by methods that allow for poor weldability and usually also allow for a final harden and temper heat treatment.

Corrosion resistance is lower than the common austenitic grades, and their useful operating temperature range is limited by their loss of ductility at sub-zero temperatures and loss of strength by over-tempering at elevated temperatures.

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Related Specifications

  • 440C
  • UNS44004
  • 1.4125

Properties

Chemical Composition

Applications

  • Rolling element bearings
  • Valve seats
  • High quality knife blades
  • Surgical instruments
  • Chisels

Characteristics

  • Excellent hardness
  • High wear resistance
  • Good mechanical strength
  • Good fatigue resistance
  • Moderate corrosion resistance

Additional Information

Weldability

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