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 Designation

    MTEK 440C

  • Poured At:

    Carondelet Division, Sandusky International Division, Wisconsin Centrifugal Division, Wisconsin Investcast Division

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

Calculated PREn (Minimum)

0

Heat Treatment: Anneal

NOTES: Brinell value is MAX.

Frequently Asked Questions

Martensitic steel is a magnetic stainless steel that is heat-treatable and used for applications requiring high hardness.

Martensitic steel is used in chemical and food processing equipment, impellers, turbine engine components, and wear-resistant parts where hardness and strength are critical.

Austenitic steel is non-magnetic, corrosion-resistant, and ductile. Martensitic steel is magnetic, harder, heat-treatable, and more wear-resistant but less corrosion-resistant.

Martensitic steel offers high hardness, wear resistance, and strength after heat treatment, ideal for demanding mechanical applications.

Yes, martensitic steel can be heat treated through quenching and tempering to increase hardness and mechanical performance.

Yes, martensitic stainless steel is magnetic due to its body-centered tetragonal (BCT) structure after quenching.

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