Effect of Heat Treatment on Tribological Behavior of Cr12Mo1V1Co Steel

Relationships among processing, microstructure, and properties of Cr12Mo1V1Co steel under various quenching and tempering conditions were systematically investigated, with particular emphasis on tribological behavior. The microstructural evolution during heat treatment was characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, and thermodynamic calculations. Reciprocating wear tests were performed with wear-scar morphologies analyzed using a three-dimensional optical profiler. The results reveal that the dominant wear mechanisms of Cr12Mo1V1Co steel are abrasive wear, oxidative wear, and fatigue wear under the present experimental conditions. Hardness represents the primary factor controlling the wear rate. High-hardness specimens deliver superior resistance to plastic deformation, which provides sufficient mechanical support for the oxide layer. This minimizes deformation within both the oxide film and the matrix during reciprocating friction, suppresses oxide spallation and mitigates abrasive, oxidative, and fatigue wear. The fracture and pull-out of large irregular M7C3 carbides constitute another important wear mechanism, and the associated carbide-originated wear can be alleviated via carbide edge dissolution triggered by elevated quenching temperatures. Considering both critical factors, specimens after 1100 °C quenching + 480 °C tempering and 1120 °C quenching + 500 °C tempering achieve optimal wear resistance among the investigated heat treatments under the present testing conditions.