Ferrite stainless steel is a kind of stainless ones with ferrite microstructure.The amount of chromium content in the steel is from 11% to 30%, with a body-centered cubic crystal structure. The steel is generally free of nickel with a small amount of Mo, Ti, Nb and other elements sometimes. Ferrite stainless steel has the advantage of high thermal conductivity, low coefficient of expansion, good oxidation resistance, excellent resistance to stress corrosion,. However, ferrite stainless steel has poor plasticity, ductility and great loss of corrosion resistance after welding and other shortcomings, thus deserving careful consideration when using it. And the use of defining technology (AOD or VOD) on ferrite stainless steel can make it widely used.