In many industrial applications, stainless steel provides satisfactory corrosion resistance. According to the experience of use, in addition to mechanical failure, the corrosion of stainless steel is mainly manifested in: a serious form of corrosion of stainless steel is local corrosion (ie, stress corrosion cracking, pitting corrosion, intergranular corrosion, corrosion fatigue, and crevice corrosion). . The failure caused by these localized corrosion accounts for almost half of the failure cases. In fact, many failures can be avoided through reasonable selection.