Product Code: PIC2008_708

Study on Welding Characteristics of Combining Laser Welding and Resistance Seam Welding Joined Ti6Al4V Alloy Lap Joints
Authors:
Xinge Zhang, Harbin Institute of Technology; Harbin Peoples Republic of China
Liqun Li, Harbin Institute of Technology,; Harbin Peoples Republic of China
Zhenglong Lei, Harbin Institute of Technology; Harbin Peoples Republic of China
Yanbin Chen, Harbin Institute of Technology; Harbin Peoples Republic of China
Presented at PICALO 2008

With deep penetration laser welding of lap joint and tee-joint, porosity is apt to occur and melting width at lap interface is too narrow to support high shear load; on the other hand, the process needs precise material fixture tolerance. So, in this study, combining laser welding and resistance seam welding into one manufacturing process is presentednamely lap joint or tee-joint are carried out by laser welding followed by resistance seam welding. Using the process of combining laser welding and resistance seam welding, lap joints of Ti6Al4V alloy sheet with 1.5mm thickness were tested. The results indicate, compared with V type weld cross section of laser welding, the weld cross section of combined process is type; melting width at lap interface is greatly enhanced. Inspecting weld specimens using X-rays, combined process suppresses the porosity commonly forming in the laser welding. Metallographic study of combined process joined weld shows that the base metal consists of small percentage of the β phase distributed at the α grain boundaries; the HAZ microstructure is a mixture of martensitic α, acicular α and primary α; The microstructure of fusion zone reveals acicular α structure transformed from β grains. The joints of combined process rupture in the HAZ; the average tensile shear strength is 787.3 MPa and the fracture is characterized by a ductile dimple feature, but the laser welding specimens peel across lap interface because of inadequate melting width.