Effect of Pre-corrosion Damage on Dry Sliding Wear Behavior of Differently Heat-Treated Martensitic Stainless Steel

This study explored the effect of pre-corrosion damage on the tribology behavior of the austenitized and the different tempered conditions of 13 wt.% Cr martensitic stainless steel under dry sliding conditions using a "ball on plate" configuration. Corrosion immersion experiments were performed in 5 wt.% HNO3 solution at room temperature for 30 min. The austenitized and the tempered at 300 degrees C (T300) specimens displayed the attack along the prior austenitic grain boundaries, whereas the specimens tempered at 550 (T550) and 700 degrees C (T700) showed intergranular plus interlath corrosion and uniform corrosion, respectively. Subjecting this corrosion-damaged specimens to dry sliding revealed non-monotonic friction and wear behavior with tempering temperature. The microstructure and the type of corrosion attack together determined the overall wear performance of the tempered conditions. The specific wear rate (k) decreased in the order k(T700) > k(T550) > k(T300) similar to k(austenitized). The k value of the austenitized and the T300 specimens (similar to 32 - 35 x 10(-6) mm(3)/Nm) is observed to be 12 and 15 times lower than the k value of T550 (similar to 408 x 10(-6) mm(3)/Nm) and T700 (similar to 495 x 10(-6) mm(3)/Nm) specimens, respectively. The reason for the lower k value is due to the continuous, thick (similar to 4 mu m thickness) Cr-rich tribo-film that formed on the wear track and acted as solid lubricant. The T550 and T700 specimens had a discontinuous Fe-rich tribo-film on the wear tracks; therefore, rubbing in the presence of harder and loose Fe-rich oxides particles led to severe adhesion plus galling in T550 and smearing plus plastic deformation in T700 specimens. It was also found that the wear rate and surface damage are reduced for pre-corroded austenitized and T300 specimens compared to the respective unattacked pristine specimens; however, the opposite effect was observed in T550 and T700 specimens.