Failure analysis and wear resistance of 7Cr7Mo2VSiNi steel for disc cutter

This study identifies the causes of failure in disc cutter and investigates the hardness and wear resistance of 7Cr7Mo2VSiNi steel. The chemical composition, microstructure, hardness, and fracture surfaces of a disc cutter exhibiting edge chipping failure are analyzed. The tribological properties of 7Cr7Mo2VSiNi steel are evaluated using the rotary module of the Rtec multifunctional friction and wear testing machine. Key parameters and wear surface morphology are systematically examined to assess wear performance and wear mechanisms. The results indicate that the fracture of the disc cutter is brittle due to its high hardness. Hardness, average friction coefficient, and wear rate display distinct trends under different heat treatments. After quenching at 1100 °C and tempering at 580 °C for three cycles, the steel exhibits a hardness of 59.1 HRC, a friction coefficient of 0.5 (±0.03), and a wear rate of 1.7 × 10 − 6 g m − 1 , respectively. The predominant wear mechanism is identified as abrasive wear. Based on hardness values and wear performance, the optimal processing parameters for 7Cr7Mo2VSiNi steel in disc shear applications are determined to be quenching at 1100 °C and tempering at 580 °C for three cycles.