Influence of porosity on the sliding wear behavior of sintered Fe-1.5Mo-0.7C steels

Fe-1.5Mo-0.7C steels with different porosity can successfully be prepared by using traditional compacting, vacuum sintering, and in part Hot Isostatically Pressing (HIPing). Their dry sliding wear behavior in both as-sintered and heat treated states were investigated. When porosity is lower than 6.2%, further decreases of porosity have less influence on the wear coefficient of both as-sintered and heat treated steels. Pores in the sintered steels collect the debris during the rubbing process, and therefore the disadvantage in wear process due to the poor hardness and mechanical strength caused by high porosity is partly compensated for. During dry sliding the as-sintered steels have three types of wear mechanisms (i.e., oxidational wear, abrasive wear, and delamination wear), while oxidational wear and delamination wear are the main regimes in heat treated steels. Oxidation leads to the wear of sintered steels and in the meantime the oxides attached to the rubbing surface further lower intense wear of the rubbing system. Abrasive wear and delamination wear, which result in flake debris, are responsible for high wear coefficients.