Effect of Scanning Mode on Microstructure and Physical Property of Copper Joint Fabricated by Electron Beam Welding

Abstract

Copper T2 thin sheet thickness of 2 mm by vacuum electron beam welding, scanning electron microscopy, optical microscopy, microhardness tester, and tensile testing machine was used. The formation of the weld surface by different scanning methods was studied. The influence of cross section morphology and microhardness of welded joints and The Effect of microstructure on mechanical properties of the welded joint. The results showed that in working distance is 300 mm and the accelerating voltage U = 60 kV, focusing current If = 502 mA, welding speed V = 800 mm/min and electron beam flow Ib = 27 mA situation, without the addition of scanning, the welded joint with good forming and no macroscopic defects can be obtained. Under the same conditions contrast to add the scanning mode of welding and derived welding in the process of adding triangle wave scanning, not only the forming good welded joints can be attained, but also the welding joints hardness values and tensile strength are improved. The average tensile strength of the welded joint is 178.8 MPa, the maximum tensile strength can reach 85% of the base metal, and the elongation rate is 84.5%, which is the weakest in the weld fusion zone compared with the whole weld zone.