Microstructure and Properties of 3D-GH3625 Electron beam welded

GH3625 superalloy is a key part material in the field of aviation, aerospace and chemical industry. The vacuum electron beam docking test was for GH3625 laser 3D printing plate with 4mm thickness. The microstructure and mechanical properties of welded joint under optimum welding process are analyzed. The causes of thermal crack in the heat affected zone of electron beam welding joint of nickel base superalloy were studied. The results show that the existence of low melting eutectic and composition segregation is the main cause of the hot crack. The grain size and grain boundary in the weld are measured by EDS spectrometer, and it is found that Nb elements migrate to the grain boundary during the welding process. The brittle refractory compound is formed with the residual carbon element in the substrate, which reduces the adhesion of the grain boundary and leads to cracking. The microhardness of the welded joint is a symmetrical distribution with the center line of the weld as a symmetry axis, and the whole is "M" shape. The average hardness of the welded joint is higher than the base metal.