Microstructure and mechanical property of WC-10Co/RM80 steel dissimilar resistance spot welding joint

In this work, resistance spot welding (RSW) was used to weld dissimilar metals of cemented carbide (WC-10Co) and high strength steel (RM80). The mechanical property and microstructure of welded joints were analyzed by shear test, scanning electron microscopy and micro X-ray diffraction, establishing the corresponding relationship between the mechanical property of welded joints and microstructure. The results show that with the increase of welding current, the shear strength of welded joints first increased and then decreased, the maximum of which under the optimal welding process was 924 MPa. The characteristics of five interface bonding types were clarified, whose proportion under different welding currents was calculated, and the contribution of each interface bonding type to the performance of welded joints was studied based on the mechanical property and fracture mechanism.