Pitting Reason on the Surface of 30CrMnSiA Steel

Pitting defects appeared on the surface of 30CrMnSiA alloy steel parts were tested and analyzed, and accelerated corrosion test was carried out by immersion method in HCl solution. The results show that electrochemical corrosion could cause pitting; the interface between MnS inclusions and matrix in steel was the origin of pitting; and the occurrence of pitting was related to the high temperature and high humidity environment of parts storage. In response to this situation, it is recommended to protect the surface by applying protective oil on the surface.