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Type 431 Stainless SteelType 431 Stainless Steel

Hardenable Martensitic Stainless Steel Alloy

Type 431 is a hardenable martensitic stainless steel alloy which has a combination of high tensile and torsional strength - this makes it well suited to shaft manufacture.

The alloy is intended for use in applications requiring good strength and toughness combined with reasonable corrosion resistance. As the alloy offers considerable resistance to saltwater corrosion, it is used widely in marine equipment and systems. Type 431 is easily machined in the annealed state but welding is difficult due to cracking and it is recommended that the material is preheated to improve welding performance.

Key Features:

Type 431 stainless steel is a heat treatable martensitic stainless - the alloy offers high tension and torsional strength and is well suited in the manufacture of shafts. However, welding is poor and the material cannot be easily cold worked.

Technical Assistance

Our knowledgeable staff and resident metallurgists will be pleased to assist you further on any technical topic. Smiths Metal Centres Limited also boasts an in-house UKAS Accredited Testing Laboratory which is unique within the multi-metal and plastic stockholding sector. We believe this underlines our total commitment to quality and our ethos of being the complete service provider.



Download Type 431 Stainless Steel Datasheet

Typical Applications:

  • Marine systems
  • Pump & propeller shafts
  • Outboard motor drive shafts
  • Valve stems
  • Aircraft components
  • Axles


We offer Type 431 Stainless Steel in round bar, plate, sheet and tube. We provide dedicated processing services throughout the Smiths Group - with more than 30 band saws and a fully automated magazine feed CNC rod blanking line, we can process your material to your exact requirements.

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