Microstructure and properties of 42CrMo steel ring formed by centrifugal casting and ring rolling after heat treatment

Abstract

In order to achieve good mechanical properties of 42CrMo steel ring formed by centrifugal casting and ring rolling, the ring was quenched at 840℃ and tempered at 590℃ after ring rolling. Mechanical properties and microstructure of the ring were detected, and tensile and impact fracture morphologies were observed. The results show that the average grain size of the rolling ring is small, and the grain size in the middle layer is relatively coarse than the inner and outer layer. After quenching and tempering, the crystal grain grows up to a certain extent because the residual stress is released and the activity of grain boundaries is increased and the microstructure changes from lamellar pearlite to tempering sorbite, the fracture form changes from cleavage fracture to ductile fracture, and the strength and hardness decrese to a certain extent while ductility and toughness improve significantly, the good comprehensive mechanical properties can be obtained and meet the technical requirements.