A study on hot deformation behavior of 40Cr/Q345B bimetal

Abstract

The hot deformation behavior of 40Cr/Q345B bimetal during hot compression bonding was studied using the isothermal compression method. A true stress–strain curve of the bimetal was obtained and modified to eliminate the effects of friction. The results show that the flow stress increases with decreasing deformation temperature and increasing strain rate. By analyzing the relationship of stress, deformation temperature, and strain rate, the constitutive equation of 40Cr/Q345B bimetal was obtained. The hot processing maps of 40Cr/Q345B bimetal under different strains are drawn. Through microstructure characterization, 40Cr/Q345B bimetal formed metallurgical bonding under the deformation process of this study. Combined with the hot processing map, microstructure, prior austenite grain, and microhardness distribution, it is proposed that the optimal deformation parameters of 40Cr/Q345B bimetal is 1050–1150°C and 0.02–0.4 s−1.