Experimental and temperature field simulation study of Inconel 718 surface cladding based on vacuum electron beam heat source

Abstract

By vacuum electron beam welding machine based on simulation of temperature field of NiCrBSi, experiment was conducted by vacuum electron beam surface cladding (VEBSC). The microstructure and friction wear properties of the specimens were analyzed by scanning electron microscope (SEM), electron backscatter diffractometer (EBSD), microhardness tester and friction wear tester under different welding beam currents (IW), respectively. The results show that the grain orientation in Inconel 718 in the rolled state is very dispersed and consists of equiaxed austenite grains (about 15 μm) with a high number of annealed twins. The internal orientation difference becomes relatively uniform after VEBSC, and a large number of elongated needle-like grains (about 200–300 μm) appear in the surface layer. At the same time, the low angle grain boundary of the clad layer (CL) of the specimen increases and then decreases with the increase of IW. When IW = 18 mA, the specimen surface hardness reaches a maximum value of 632.5 HV, and the friction coefficient is at least 0.25. The wear mechanism after cladding is dominated by plowing and abrasive wear to improve the wear resistance of the material. However, the high temperature oxidizing properties do not change much.