Friction Torque and Heat Input Characteristics During Continuous Drive Friction Welding of Aluminum to Steel

Friction torque is a comprehensive manifestation of friction resistance during the continuous drive friction welding. By monitoring the real-time voltage and current of main motor stator during the continuous drive friction welding of 1050 pure aluminum to E235 steel, evolutions of friction torque on the joint interface were obtained and the effects of rotation speed and forging pressure on the friction torque and heat input of each welding stage are analyzed. The results show that the initial friction stage is the process of heat input accumulation, where "stick" friction heat generation is predominant. When rotation speed is low, friction torque curve only has a peak or the initial and final peak features are not obvious, the whole friction process is unstable. With the increasing of rotation speed, friction torque increases, the heat input of initial friction stage, the quasi-steady state stage and the whole process is increased, but heat input in forging stage is slowly reduced due to the decrease of the friction heating power during the forging stage. Final peak torque and heat input in forging stage are positively correlated with the change of forging pressure.