Properties of 316L stainless steel joints brazed with corrosion resistant nickel-based filler metal

The brazing of 316L stainless steel was carried out by using Nickel based filler metal BNi685 foil. The effect of brazing clearance on the microstructure and mechanical properties of brazed joint was studied. The corrosion resistance of joints brazed with the new BNi685 foil, commercial BNi2 and BNi685 paste filler metals were also compared. The results show that with the increase of gap clearance, the tensile strength of the brazed joint decreases gradually, and the microhardness at the center of the joint increases. When the brazing clearance is 50 μm, the joint achieved a maximum tensile strength of 244 MPa. The microstructure of the brazing seam is mainly composed of Ni_2.9Cr_0.7Fe_0.36 ductile phase and a small amount of FeNiCr(P) brittle phase. With the increase of gap clearance, the FeNiCr(P) brittle phase at the center of the brazing seam increases, and the Ni_2.9Cr_0.7Fe_0.36 ductile phase decreases. The corrosion resistance of the BNi685 brazed joint is superior to that of the BNi2 and BNi685 paste brazed joint. BNi685 filler metal has a strong application potential for EGR coolers fabrication.