Alloy Grade UNS: 440C – Martensitic Stainless Steel

  • Overview

    440C is a high-carbon martensitic stainless steel renowned for its exceptional hardness and wear resistance. When fully hardened and stress relieved, it ranks among the hardest stainless steel grades, making it exceptionally resistant to abrasive wear and ideal for applications involving friction and sliding contact. This hardness is attributed to its high carbon content and the presence of hard carbides in its microstructure. While offering good corrosion resistance thanks to its chromium content, 440C requires careful handling during welding, including preheating and post-weld stress relieving, to prevent cracking. This magnetic alloy is machinable in its annealed condition, making it suitable for applications demanding a combination of hardness, wear resistance, and moderate corrosion resistance.

  • Typical Uses

    Valve components, pump parts, shaft sleeves, and bearings.

  • MetalTek Grade

    MTEK 440C

Similar Specifications

Cast UNS: J91639

Wrought UNS: S44004

Wrought Grade: 440C

Cast Grade: 440C

Military/AMS: AMS 5352

* AMS specifying investment casting.

Typical Chemical Composition (% by wt.)

Aluminum: n/a

Carbon: 0.95-1.20

Chromium: 16-18

Manganese: 1

Iron: BAL

Copper: n/a

Nickel: 0.75 MAX

Lead: n/a

Tin: n/a

Silicon: 1

Zinc: n/a

Other: Mo 0.25-0.75

Minimum Mechanical Properties

Brinell Typical:

0

Heat Treatment: Anneal

NOTES: Brinell value is MAX.

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