Tribological Characteristics of HSLA TRIP Steel Containing Meta-Stable Retained Austenite

Friction and wear characteristics of a new Transformation-induced plasticity(TRIP) steel containing 0.22C-1.50Si-1.65Mn used in automotive construction parts was studied on SST-ST Disc-Pin friction tester.Volume fraction of friction-induced metastable retained austenite transformed to martensite in the wear trace was measured by using X-ray diffractometer.Results show that TRIP steel exhibited lower friction coefficient and better wear resistance than that of dual-phase steel containing same composition and volume fraction of ferrite.Because of triple-stress state during friction testing,an amount of retained austenite in the center of wear zone transformed to martensite compared to the non-wear zone which results in relaxing inter-stress and transformed martensite strengthening the surface layer,consequently,improving the friction and wear properties.Research on TRIP steel illustrates that one can effectively use deformation-induced transformation of meta-stable austenite during friction to improve tribological performance of materials.