Study on solidification behavior and microstructure-property of 304 SS/T2 copper electron beam welded joints

The solidification behavior and microstructure characteristics of EB welded joints of 304 austenitic stainless steel to T2 copper were studied by adjusting the power output and different welding offsets. The joint characteristics were characterized by optical microscopy,scanning electron microscopy,energy dispersive spectroscopy and tensile test. The results show that good weld appearance of 304 stainless steel to T2 copper can be obtained by EB welding,and the joint has no obvious defects such as porosity and micro-cracks. The highest tensile strength of the joint reaches up to 246 MPa,which is nearly equal to that of copper substrate. Beam offset has a great influence on the strength of the joints. Beam focus on copper can result in coarse grains in the heat affected zone of copper side,and focus on steel side can lead to bad fusion and hot crack formation. There is no brittle intermetallic compounds between steel and copper. The phase composition of weld is mainly composed of ε phase,γ phase and intragranular α phase.