AISI 431 Martensitic Stainless Steel Chemical Properties, Grade, Tables and PDF Online

The AISI 431 is a martensitic stainless steel with a well-established reputation for outstanding corrosion resistance and high toughness. Components, which would typically have 15 to 17% of chromium, 1.25 to 2.5% of nickel, 1% of manganese, 1% of silicon, 0.04% of phosphorus, and 0.03% of sulphur, are a part of it. For this level of hardness, outstanding mechanical properties and only average corrosion resistance features makes this grade a good choice for applications in which both corrosion resistance and mechanical strength is required. The common applications are gear, shaft, valves, fasteners and surgical instruments, for instance. All types of AISI 431 grade of stainless steel are intended to meet the various domestic and international standards and specifications available. For the purpose of its complete use, engineers and manufacturers rely upon charts and comprehensive documents as pdf files for its grades, properties, and chemical composition.

AISI 431 Martensitic Stainless Steel Chemical Composition And Grade Table

AISI 431 is a martensitic grade of stainless steel that combines a good level of corrosion resistance along with high strength. It is the chemical composition that usually contains 15-17% of chromium, 1.25-2.5% nickel, 1% manganese, 1% silicon, 0.04% phosphorus, and the reminder is iron. This does the metal specifying that high mechanical properties and resistance to mildly corrosive environments are one of its features. The AISI 431 grade is frequently applied in making shafts, fasteners, machine parts, e.g., pumps, valves and surgical instruments, thanks to its improved performance characteristics.

AISI 431 Martensitic Stainless Steel
Elements C Mn Si P S Cr Ni
Min (%) - - - - - 15 1.25
Max (%) 0.20 1 1 0.040 0.03 17 2.50

Advantages and Disadvantages of AISI 431 Martensitic Stainless Steel


  • High Strength: Offers high tensile strength, suitable for high-stress conditions.

  • Corrosion Resistance: Provides average corrosion resistance for use in mildly corrosive environments.

  • Heat Treatability: Can be heat treated to achieve desired mechanical characteristics.

  • Machinability: Relatively better machinability compared to other martensitic stainless steels.


  • Limited Corrosion Resistance: Corrodes readily in aggressive environments containing chlorides and acids.

  • Weldability Challenges: Prone to cracking during welding, requiring careful management of welding parameters.

  • Toughness: Less tough than austenitic stainless steels, susceptible to brittle fracture.

  • Surface Finish: Achieving a good surface finish can be challenging due to its hardness.

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