Influence of rolling temperature on interface properties of the cross wedge rolling of 42CrMo/Q235 laminated shaft

Abstract

The cross wedge rolling (CWR) method was used to produce laminated shafts of chromium-molybdenum steel (42CrMo). The effect of the rolling temperature on interface properties of composite 42CrMo/Q235 laminated shaft were explored, for example, the interface micro-structure, chromium diffusion, micro-hardness, bonding strength, and tensile fracture morphology. Results indicate that after rolling, the core material (Q235) and the clad material (42CrMo) combined effectively and formed a notable interface. Under high tem-perature rolling and composite binding, the chromium dif-fused near the interface. By rising the rolling temperature, the diffusion depth of chromium from the clad material to the core material increased. Near the interface of 42CrMo/Q235, the micro-hardness changes gradient. By rising the rolling temperature, the micro-hardness of same location decreased. The maximum interface bonding strength is 1100 °C, the maximum tensile strength is 532.0 MPa, and the maxi-mum shear strength is 422.3 MPa. Scanning electron microscope (SEM) images display the tensile fracture with a typical ductile dimple fracture pattern. Raising the rolling tempera-ture, the size of the dimple increased and the oxide at the bottom of the dimple decreased. At a rolling temperature of 1100 °C, the interface bonding strength should be the highest, which correlated with the interface bonding strength test results.