耐腐蚀性镍基箔带钎料钎焊不锈钢接头性能

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

关键词:  真空钎焊  镍基钎料  钎焊间隙  耐腐蚀性

Key words:  vacuum brazing  nickel-based filler  gap clearance  corrosion resistance

摘要:

采用新型耐腐蚀性镍基箔带钎料BNi685对316L不锈钢进行真空钎焊，研究了钎焊间隙对钎缝组织及力学性能的影响，对比了新型BNi685钎料钎焊接头与商用BNi2钎料，BNi685膏状钎焊接头的耐腐蚀性. 结果表明，随着钎焊间隙的增加，钎焊接头的抗拉强度逐渐降低，钎缝中心的显微硬度增加. 钎焊间隙为50 μm时，接头平均抗拉强度为244 MPa，钎缝组织主要由Ni_2.9Cr_0.7Fe_0.36，CrNiP，Cr₃P，Ni₅Cr₃Si相组成. 随着钎焊间隙增加，钎缝中心的CrNiP，Cr₃，Ni₅Cr₃Si相增多，Ni_2.9Cr_0.7Fe_0.36相减少. BNi685钎料钎焊接头的耐腐蚀性优于BNi2和BNi685膏状钎料钎焊接头，在EGR冷却器制造领域具有较大的应用潜力.

Abstract:

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.