Abstract: Aluminum/steel hybrid structure is widely used in automobile manufacturing, energy, aerospace and other fields, in the Continuous drive friction welding(CDFW) process, due to the different flow characteristics of base metal and radial friction torque distribution, it is difficult to remove oxides and impurities on the interface, and the uneven distribution of interface heat generation power and intermetallic compounds(IMCS) at the interface, this will adversely affect the joint properties. Taking 1060 pure aluminum and Q235 low carbon steel bars as the research object, the welding experiment was carried out at the taper angles θ of 5°, 10°, 15°, 20°and 25° on the terminal face of the steel rod to be welded, to analyze the changing rules of interface temperature, friction torque, energy input and joint strength under different taper degrees. The results show that with the increase of taper angle, the initial peak torque decreases, the steady-state torque, post peak torque and the energy input during the whole welding process first increase and then decrease, and the energy input during the initial friction stage increases; the temperature and strength changes in the radial direction of the joint at 10°-15° tend to be gentle. The conical structure moves the high temperature region of heat flow at the interface, after 20°, the peak temperature point appears at 1/3R, and the highest intensity appears at the area near 1/2R. In the CDFW process, the appropriate taper angle can improve the inhomogeneity of interface temperature and mechanical properties under the condition of sufficient welding heat production, so as to obtain good performance joint, which provides some theoretical guidance for the terminal structure design of dissimilar metals.

Key words: taper angle, inhomogeneity, interface temperature, friction torque, tensile strength