431 Stainless Steel Supply


431 stainless steels are martensitic, heat-treatable grades with excellent corrosion resistance, torque strength, high toughness and tensile properties. All these properties make them ideal for bolt and shaft applications. These steels, however, cannot be cold-worked owing to their high yield strength, hence they are suitable for operations such as spinning, deep drawing, bending or cold heading.

Fabrication of martensitic steels is generally carried out using techniques that allow hardening and tempering treatments and poor weldability. The corrosion resistance properties of grade 431 steels are lower than that of austenitic grades. The operations of grade 431 are limited by their loss of strength at high temperatures, due to over-tempering, and loss of ductility at negative temperatures.

431 Stainless Steel Properties

Corrosion Resistance: 431 stainless steel has good corrosion resistance in a wide range of environments. It can withstand exposure to water, mild acids, and other corrosive substances without corroding or rusting.

Strength: 431 stainless steel has high strength and hardness, making it ideal for applications that require high mechanical strength. It has a minimum tensile strength of 760 MPa and a minimum yield strength of 345 MPa.

Ductility: 431 stainless steel has moderate ductility, which means that it can be formed and shaped, but not as easily as other types of stainless steel. This property makes it suitable for applications that require moderate ductility.

Weldability: 431 stainless steel is easily weldable, but it may require preheating to prevent cracking. It can be welded using common welding techniques, such as TIG, MIG, and resistance welding.

Magnetic Properties: 431 stainless steel is magnetic, which makes it suitable for applications that require magnetic properties.

Heat Resistance: 431 stainless steel has good heat resistance and can withstand moderately high temperatures without losing its strength or corrosion resistance. It can withstand temperatures up to 760°C (1400°F) without undergoing any significant change in its properties.

Chemical Composition

Composition ranges of grade 431 stainless steels


Mechanical Property

Condition Annealed*T
Tensile Strength (MPa)Min 850
 Max 1000
0.2% Yield Strength (MPa)Min 635
Elongation on 5.65√S0 %Min 11
Izod Impact Valua J mmMin 63 34
   63 20
Hardness HBMin 248

431 Stainless Steel Applications

431 stainless steel is a martensitic stainless steel with high tensile strength and good corrosion resistance. It is often used in applications requiring a combination of strength and corrosion resistance. Here are some common applications of 431 stainless steel:

  1. Fasteners: 431 stainless steel is commonly used for the manufacturing of bolts, nuts, screws, and other fasteners. Its high tensile strength makes it suitable for applications where strong connections are essential.
  2. Shafts and Axles: Due to its high strength and hardness, 431 stainless steel is employed in the production of shafts and axles in various industrial applications, including machinery and equipment.
  3. Pump and Valve Components: Components such as pump shafts, valve stems, and fittings in the fluid handling industry may be made from 431 stainless steel for its corrosion resistance and strength.
  4. Marine Applications: Certain marine components, such as propeller shafts and marine hardware, may utilize 431 stainless steel due to its resistance to corrosion in marine environments.
  5. Aircraft Parts: In aerospace applications, 431 stainless steel may be used for certain components that require high strength and corrosion resistance, such as aircraft landing gear components.
  6. Chemical Processing Equipment: 431 stainless steel is suitable for manufacturing components in chemical processing equipment, including valves, pumps, and fittings, where resistance to corrosive chemicals is essential.
  7. Food Processing Equipment: Some components of food processing equipment, such as conveyor systems and blades, may be made from 431 stainless steel due to its corrosion resistance and strength.
  8. Medical Devices: Certain medical devices, especially those requiring high strength and corrosion resistance, may use 431 stainless steel in their construction.
  9. Cutlery and Surgical Instruments: The combination of hardness, strength, and corrosion resistance makes 431 stainless steel suitable for certain types of cutlery and surgical instruments.
  10. Oil and Gas Industry: Components used in the oil and gas industry, including pump shafts, valves, and drilling equipment, may be made from 431 stainless steel for its strength and resistance to corrosive environments.