Investigation on properties of joints vacuum brazed with nickel-based adhesive tape filler metal

In this paper, a nickel-based adhesive tape filler metal was used to braze 316L stainless steel. The melting characteristics of the filler metal were analysed by thermal analyzer. The wetting spread and brazing properties of the filler metal on 316L stainless steel were tested by vacuum brazing furnace. Then the morphology and composition of the brazed joint were analysed. The shear strength and microhardness of the brazed joint were tested. The results show that the organic matter in the brazing filler metal can be completely volatilized before the brazing filler metal starts to melt. The brazing filler metal has a good wetting and spreading effect on the surface of stainless steel, and there is no black carbon residue, so it has no effect on the brazing performance. The microstructure of the brazed joints with nickel-based adhesive tape filler metal shows that the joint interface has a good metallurgical bond, and there are no defects such as cracks and pores in the brazing joints. The interface structure is composed of nickel-based solid solution phase, Fe-Cr intermetallic compound phase, and chromium boride phase compound. The average shear strength of the brazed joint is 183.2MPa. The microhardness of the center of the brazing seam reaches 2175.37HV. From the center of the brazing seam to the direction of the base material, the microhardness gradually decreases.