What Is 431 Martensitic Stainless Steel

What is 431 martensitic stainless steel

AISI 431 S43100 SUS431 1.4057 Stainless steel round rod

431 stainless steel is a high-chromium, low-nickel, high-hardenability martensitic stainless steel with high strength and good corrosion resistance, which is usually hardened and tempered in the tensile range of 850-1000 Mpa (Condition T) in the Brinell range of 248-302.

Corrosion resistance
431 stainless steels have considerable resistance to salt water, but they are less resistant to tropical water than grade 316 steel. The overall corrosion resistance of 431 steel is similar to or slightly lower than that of 304 steel. 431 stainless steel with a smooth surface finish performs well under tempered and hardened conditions.

Heat resistance
431 stainless steel is resistant to scaling under intermittent conditions of 925°C and continuous operating conditions of 870°C. In general, due to the loss of mechanical properties, these steels cannot be used at temperatures higher than the standard tempering temperature.

forge
Heat evenly to 1150ºC - 1200ºC until the temperature is uniform throughout the section. Do not soak, but start forging immediately. Do not overheat, as this can lead to a loss of toughness and ductility. Do not forge below 900ºC Forgings should be cooled to room temperature as slowly as possible in dry lime or ash and immediately subcritical annealed.

Low temperature characteristic
It is not recommended to use 431 stainless steel at temperatures below zero because the impact properties are substantially reduced in line with most steels except austenitic steel types.

Cold bending
Due to the high yield strength, it will be very difficult in the hardened and tempered state and is generally not recommended for use.

Hot bending
In the hardened and tempered state, it is not recommended because it will affect the mechanical properties in the heat-affected area.

weld
The welding of grade 431 stainless steel is difficult due to the possibility of cracking. It is recommended to preheat the material to 200-300°C before welding and to perform post-welding heat treatment at 650°C. Class 410 filler rods can be used for welding.

process
431 steel is easy to work in the annealed state. However, if the hardening temperature of these steels is higher than 30HRC, it is extremely difficult to process these steels.

Apply
The 431 has been successfully used in a variety of aircraft and general industrial applications. These include fasteners, bolts, valve parts and chemical equipment.