Effects of deep cryogenic treatment on the dry sliding wear performance of ferrous alloys

In this study, the effects of cryogenic processing on the dry sliding wear performance and microstructural features of five common engineering materials were investigated. Significant improvements were found in the wear performance of a pearlitic low carbon steel brake material, as well as AISI A2, D6 & M2 tool steels. Optical and scanning electron microscopy of selected specimens indicated a range of changes due to deep cryogenic treatment including graphite flake degradation and pearlite refinement in cast iron and low carbon steel that was previously unreported in the literature. In tool steels, carbide precipitation and microstructural uniformity reported by other investigators was observed. Macro- and micro-hardness testing revealed no significant changes in any of the materials except for the low carbon steel tested, in which measured improvements were judged to be as a result of the refinement of the pearlite matrix due to deep cryogenic treatment.