Inconsistent wear behaviour of cryotreated tool steels: role of mode and mechanism

This report aims to reveal the cause of wide variation in the reported degree of improvement in wear resistance of cryotreated tool steels. Sliding wear tests at different normal loads have been carried out on conventional and cryotreated AISI D2 steel specimens together with SEM examinations and EDX microanalyses of the surfaces and subsurfaces of the worn specimens and that of the generated debris. The obtained results reveal that when the modes and mechanisms of wear are similar for both types of specimens, mild oxidative at lower load or severe delaminative at higher load, the improvement in wear resistance is 1.6-2.2 times. At the intermediate load, the modes and mechanisms are dissimilar, and the observed improvement is as high as 53.2 times. The reported varied degree of improvement in wear resistance by cryotreatment has been attributed to the operating test conditions that govern the modes and mechanisms of wear.