Microstructure comparison of resistance butt welding and cold-pressure welding of zinc alloy wire

The fracture morphology of butt-welded joint with over mode was observed with metallographic microscope and scanning electron microscope (SEM) to enhance the overmoded rate of butt-welded joint of zinc alloy wire.The results show that the tension fracture of zinc alloy wire joint made by cold-pressure welding was ductile fracture of hardened material.The annealing should be performed ahead of the drawing process.After drawing the cold-pressure welded joint,the original bonding area widened and the separation of the streamline layers in bonded area became larger,and this was beneficial for releasing the stress concentration.The obvious grain growth with recrystallization occurred in resistance butt welded joint of zinc alloy wire.The generation of recrystallized grains was favorable for releasing the internal stress within the joint,which improved the plastic deformation capability of the joint and ensured the high overmoded rate of the resistance butt welded joint.