Pitting Corrosion Behavior of GCr15 Bearing Steel in Hydrochloric Acid Solution

The pitting behavior of GCr15 bearing steel in hydrochloric acid solution was studied in corrosion in-situ observation test by metalloscopy, confocal microscopy and scanning electron microscopy (SEM). The results show that the defects of pitting holes were caused by MnS inclusions. With the dissolution of steel in pits, the inclusions fell off, and the pH value in the pits decreased continuously, which led to the continuous development of pitting along the longitudinal direction. The number of pits was related to the number of exprosed MnS inclusions on the corrosion cross section. The greater the number of exposed MnS, the denser the pits on the cross section.