Corrosion Behavior of High Strength Bearing Steel GC15 in NaCl Solution

Heat-treatment of quenching and low-temperature tempering was conducted for high strength bearing steel GCr15. The changes of microstructure and corrosion behavior of the heat-treated GCr15 steel corroded in NaCl solution were studied by means of metallographic microscope, stereo microscope and electron probe. The results show that severe localized corrosion happened to the heat-treated GCr15 steel corroded in NaCl solution. There were some active points inducing localized corrosion in the heat-treated GCr15 steel, so localized corrosion occurred early in these positions. The tempered martensite in the heat-treated GCr15 steel suffered oxygen corrosion because of bad corrosion resistance, and the residual austenite in the tempered martensite could delay the further corrosion of substrate because of good corrosion resistance.