High frequency brazing of 0Cr18Ni9Nb to YG6 using Cu-based microcrystalline brazing alloys

The high frequency brazing of 0Cr18Ni9Nb stainless steel to YG6 cemented carbide was conducted by using Cu-xwt%Sn(x=7,13.5) microcrystalline brazing alloys,and the phase constitution,microstructural morphology and interfacial element distribution characteristics of brazing joint were investigated.The relationship between the microstructure of joint and the composition of brazing alloy together with atom mutual diffusion behavior was analyzed.The experimental results show that the Cu-based microcrystalline brazing alloys perform an excellent wettability and spreadability in induction brazing process.Owing to the atom mutual diffusion between the liquid Cu-based brazing alloys and the base metal to a certain extent,the metallurgical bonding of 0Cr18Ni9Nb to YG6 has achieved.The joint microstructure is dense and homogeneous,which has no defects such as slag inclusion and porosity etc.The microstructure of brazing seam consists mainly of α-Cu solid solution and a few of intermetallic compounds in the 0Cr18Ni9Nb/ Cu-xwt%Sn/YG6 joint,and the quantity of intermetallic compounds increases with the rise of Sn content.The base metals near the interface have no obvious coarsening appearance.