Grade 431 Stainless Steel and Its Uses

As stainless steel suppliers and fabricators in Perth, we have become experts on all things stainless steel. There are different grades of stainless steel for different uses. They all have different characteristics that make them unique. Here are some facts about Grade 431 stainless steel.

Uses of Grade 431 Stainless Steel

Grade 431 is a martensitic stainless steel. That means it can be hardened thermally. Grade 431 is less well-known than other grades, but is used in motors as shafts and fasteners. It is also used in the food processing industry for pumps and valves. It can be heated and cooled quickly by quenching, resulting in a hardness resembling that of a low alloy steel such as 4140. None of the austenitic grades can be hardened in this way.

Consequently, grade 431 stainless steel is one of the more versatile materials on the market. It combines high toughness and strength with above average corrosion resistance. Before hardening, it can be easily machined.


The main features of grade 431 are the inclusion of nickel and a high chromium content. The nickel makes grade 431 austenitic at high temperatures by countering the high chromium content. This allows it to be turned into a hard martensite when quenched.

Corrosion Resistance

The high chromium content makes grade 431 nearly as resistant to crevice, pitting and general corrosion as grade 304. This makes it ideal for use in the food and beverage industry. Of all the martensitic grades of stainless steel, grade 431 has the highest corrosion resistance. Corrosion resistance is at its greatest when grade 431 is hardened, tempered and has a smooth finish.

Grade 431 can be used with great success for boats in fresh water. Unfortunately, it doesn’t work well with seawater because of the salt content.

Heat Resistance

Grade 431 can withstand temperatures up to 700 °C, but are often permanently softened if they are exposed to temperatures more than 600 °C.

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