Fretting-corrosion wear of 17-4PH stainless steels subjected to different aging temperature under simulated sulfuric acid rain condition

Systematic experimental investigations were conducted to study fretting corrosion wear of 17-4PH stainless steels aged by different temperatures in a H 2 SO 4 solution (pH = 2) to simulate the sulfuric acid rain condition. The fretting corrosion wear tests under different amplitudes with a fixed normal load were carried out. The fretting coefficient, fretting corrosion wear resistance and failure mechanism under different fretting running regimes were discussed. Results show that fretting corrosion wear volume firstly decreases and then increases with increasing the aging temperature. Regardless of fretting running regimes, the microstructure of sample T2 with BCC Cu-rich precipitates (CRPs) aged at 460℃ has a best fretting corrosion wear resistance, while the lowest is the sample T4 with FCC CRPs. In partial slip regime (PSR), the damage is quite marginal, while in mixed fretting regime (MFR) and gross slip regime (GSR) the failure mechanisms are mainly delamination and ploughing. Moreover, the formation of tribo-oxidation during wear process may be helpful to improve the fretting corrosion wear resistance. Cross-section observations suggest that the tribo-layer without crack can enhance the fretting wear resistance.