Effect of sensitization on tribological behavior of AISI 304 austenitic stainless steel

This paper aims to evaluate the dry sliding wear of AISI 304 austenitic stainless steel as a function of the applied load. Samples of AISI 304 were heat treated (sensitized) to precipitate Cr23C6 carbides in the grain boundaries, and the resulting microstructure was compared to that of the non-sensitized samples. Wear testing was carried out at room temperature of 25 degrees C and a relative humidity of about 60% using a pin-on-disk apparatus. The load applied was varied from 10 to 30 N at a constant sliding velocity of 0.5 m s(-1). Wear particles were analyzed by means of scanning electron microscopy and X-ray diffraction. The results showed that the dynamic friction coefficient remained effectively constant with increasing applied load. The surface hardness measured after the wear process generally increased at higher loads due to subsurface strain-hardening, and deformation-induced martensitic transformation occurred during the wear process. Surface roughness and weight losses were found to increase with increasing the load for both sensitized and non-sensitized samples. In addition, a great amount of Cr23C6 carbides in the grain boundaries favored a size reduction of the debris generated due to wear.