Research on the influence of differential speed ratio on the microstructure and properties of 316L/Ni/EH40 composite plate by asymmetrical rolling

Five-pass asymmetrical rolling experiments with speed ratios of 1.00, 1.08, and 1.15 were carried out on 316L/NI/EH40 clad plates. The interface microstructure and mechanical properties of the rolled clad plates were analyzed by characterization and performance testing. The results show that the influence of different speed ratios on the degree of interdiffusion of elements at the bonding interface is relatively small. The interfaces between each layer are relatively flat and clear, without cracks, holes, or impurities near the interface. This feature facilitates the bonding of the clad plate. The speed ratio has little effect on the grain size on the EH40 side of the base layer, and the hardness change of the base layer is not apparent. Increasing the speed ratio increases the shear deformation of the clad plate, which promotes fragmentation and refinement of the coarse grains on the 316L side of the overlay. The mechanical properties show that increasing the speed ratio improves the properties of the asynchronously rolled plates. The speed ratio increases to 1.15, and the sample becomes relatively flat. The 316L side of the overlay shows refined grains and a uniform microstructure. The sample also demonstrates high hardness 247HV, high tensile strength 737 MPa, high shear strength 674 MPa, and good plasticity with 67 % elongation after fracture. [Display omitted]