400 stainless steel is mainly composed of ferrite and martensite, among which ferritic stainless steel usually contains no nickel, which has the characteristics of high thermal conductivity, small expansion coefficient, good oxidation resistance and excellent corrosion resistance.
Martensite stainless steel, with high carbon content, is a kind of stainless steel whose properties can be adjusted by heating, that is to say, its hardness can be improved by heat treatment, so it has high strength, high hardness and wear resistance. Therefore, 400 stainless steel has strong high-temperature oxidation resistance and is not easy to be corroded and rusted.
Application of 400 series stainless steel
Under the same chromium content, the corrosion resistance of 400 series stainless steel in oxidizing media such as atmosphere, fresh water and nitric acid is the same as that of 300 series stainless steel, and it is also better than that of 200 series stainless steel. Adding trace elements such as niobium, titanium, copper and aluminum can improve its deep drawing performance, weldability, corrosion resistance and high temperature strength, and can partially replace 300 series stainless steel.
At present, 400 series stainless steel is widely used in automobile exhaust pipes, elevators, washing machines, kitchen utensils, household appliances, medical devices, water heaters, roof panels, curtain walls and power plant equipment. It can be said that such stainless steel is also widely used.