Study on microstructure of fusing-brazing joint of aluminum to galvanized steel by pulsed DE-MIG welding

This paper put forward an arc welding method of pulsed DE-MIG welding,and introduced the basic principle of it. According to the characteristics and control requirements of this method,a pulsed DE-MIG welding experimental system based on rapid prototyping was established and it realized the dissimilar metal joining of aluminum and galvanized steel. The analysis of joint microstructure of aluminum and galvanized steel shows that Fe and Al atoms diffuse sufficiently in the intermediate interfacial region of joining of aluminum and galvanized steel. Ternary intermetallic compounds of lamellar Fe₂Al₅Zn_0.4 are generated. Rich-zinc zone is located at the weld toe,and is mainly composed of α-Al and β-Zn solid solution. Meanwhile,experiments of tensile and shear strength of overlap joints were conducted, and the results show that the maximum tensile strength is up to 186.73 MPa.