Alloy Grade UNS: 440B – Martensitic stainless steel 

  • Overview

    UNS S44003, also known as AISI 440B, is a high-carbon martensitic stainless steel that offers a balance of strength, hardness, and corrosion resistance. This alloy is part of the 440 series, positioned between 440A and 440C in terms of carbon content and properties.

  • Typical Uses

    Valve components, pump parts, and bearings.

  • MetalTek Grade

    MTEK 440B

  • Poured At:

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

Similar Specifications

Wrought UNS: S44003

Wrought Grade: 440B

Typical Chemical Composition (% by wt.)

Aluminum: n/a

Carbon: 0.75-0.95

Chromium: 16-18

Manganese: 1

Iron: BAL

Copper: n/a

Nickel: n/a

Lead: n/a

Tin: n/a

Silicon: 1

Zinc: n/a

Other: Mo 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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