Friction Welding of Cr-Zr Copper Alloy

An investigation has been made of friction welding of Cr-Zr copper alloy, which is very difficult to join by conventional fusion welding processes because of its high thermal conductivity and susceptibility to solidification cracking and blowhole formation. It was revealed that brake timing and stopping period had significant effect on the formation of weld interface in friction welding of Cr-Zr copper alloy. The weld wes established only in the center area of the forging sufrace during the friction stage. Severe metal flows were required to expand the weld interface to the whole forging surface to obtain the sound joint from those experiments. When the brake wes operated after applying an upset pressure, referred to as brake timing “after”, the adequate metal flow was generated in the weld. Optimized parameters were brake timing “after” and stopping period more than 0.3 s to join Cr-Zr copper alloy without defects. The joint efficitncy estimated form tensile strength wes more than 92% at the optimum bonding paremeters. All specimens failed in the soften area apart from weld interface on tensile test.