Study On Electron Beam Welding Performance Of Dissimilar Material Mangnese-Corpper Alloy/Steel

Variance of phyxics and mechanical property of Steel and Mn-Cu alloy are enormous, obtain good joint is difficult by conventional welding method. The electron beam welding (EBW) Vacuum electron beam welding has many advantages of high depth-width ratio of seam, small angular distortion and good metallurgic quality and etc. These advantages of EBW make its use expanding in the welding of dissimilar metals. First, in this article, feasibility of dissimilar metals joining between ZMnD-1J Mn-Cu alloy and 20# steel with electron beam welding was discussed . The experiment is proved feasibly.Secondly, process parameters of dissimilar metals joining between ZMnD-1J Mn-Cu alloy and 20# steel with electron beam welding was to be optimized. Deflection electron beam welding was brought out to improve the heat input of both side dissimilar metals and the appearance of weld surface. And, preheating welding technology was brought out to experiment 12mm thickness ZMnD-1J Mn-Cu alloy and 20 # steel electron beam welding. The results indicated: heat input is final determining factor of the appearance of weld surface. The optimum processing parameters were determined as"U: 130kV, If: 2384mA, Ib: 10mA, v: 8mm/s, Leaning steel side 0.6mm". The tensile strength of the joint was 351.5 MPa, which was 75.6% of base metal. The appearance of weld surface is good. And, the heat input is 1625J·cm-1.Then, the weld joint organizational structure and the fracture appearance were analyzed. The results indicated: it's found that the structure of weld bead was very homogeneous. Neither hole nor flaw was found in joint.The gliding fracture was approved by analyzing the appearance of fracture. The joint part divides into the Mn-Cu alloy side heat-affected zone, the welded joint area and the steel side heat-affected zone. The steel side heat-affected zone scope is smaller than the Mn-Cu alloy side heat-affected zone scope. The welded joint area divides into three parts: Welded joint fringe area Mn-Cu alloy side, welded joint central area and welded joint fringe area steel side. Fracture analysis by XRD of fracture found that much intermetallic compound which was very brittle in Welded joint fringe area Mn-Cu alloy side (zone C), which showed much weaker than other zones in joint. Fracture was found to happen in zone C through fracture appearance analysis. Intermetallic compound FeCu and FeMn3 were present on the fracture surface which were the main responsibility to brittle fracture.