Differences between austenitic martensitic and ferritic stainless steels

The internal microstructure of ferritic stainless steel is ferrite, and the content of chromium is in the range of 11.5% ~ 32.0%. With the increase of chromium content, its acid resistance is also improved. After adding molybdenum (MO), its acid corrosion resistance can be improved. The common 430 is ferritic stainless steel.

The microstructure of martensitic stainless steel is martensite. The chromium content in this kind of steel is 11.5% ~ 18.0%, the carbon content is high, and the strength and hardness of stainless steel are high. This kind of steel has poor weldability. The common 410 is martensitic stainless steel,

The microstructure of austenitic stainless steel is austenite. It is a stainless steel with austenitic structure formed by adding appropriate nickel (nickel content is 8% ~ 25%) to high chromium stainless steel. The common 300 series stainless steel is austenitic stainless steel

Martensitic stainless steel belongs to chromium stainless steel. Due to the high carbon content and more chromium carbide, the corrosion resistance of the steel decreases. Although it can be improved by heat treatment, the corrosion resistance is not high.

Ferritic stainless steel also belongs to chromium stainless steel. Low carbon content, strong corrosion resistance and good high temperature oxidation resistance.

Austenitic stainless steel belongs to chromium nickel stainless steel. It has high corrosion resistance. Good weldability and low temperature toughness, non-magnetic, easy to work hardening.