Influence of cold working on the wear of AISI 1020 steel in dry sliding contact at high current density

The wear rate and surface electrical conductivity in the sliding electrocontact of 1020 steel and quenched steel are studied as a function of the current, at a contact current density exceeding 100 A/cm2, without lubricant. The wear resistance is greater for steel with greater cold working. This may be attributed to the lower amplitude of the stress in low-cycle fatigue of the material adjacent to the contact spot of the stronger steel. The contact characteristics observed for the 1020 steel are somewhat higher than the known values for quenched steel. This may be attributed to the higher reserve of plasticity of the surface layer in 1020 steel than in quenched steel. Structural changes in the sliding surface are observed: specifically, the formation of a friction induced structure layer containing crystalline phases (FeO, α Fe, and γ Fe). An image of the worn surface shows indications of liquid phase. This phase is the result not of melting but of the appearance of highly excited atoms in a thin surface layer. © 2015, Allerton Press, Inc.