通过在BAg34CuZnSn钎料(3.5%Sn,质量分数)基材表面刷镀微米锡层,采用感应钎焊方法对316LN不锈钢进行连接。利用扫描电镜(SEM)和X射线衍射仪(XRD)分析基材表面锡镀层的结晶取向和界面形貌,以及316LN不锈钢钎焊接头的显微组织、物相组成、断口形貌,并借助万能拉力试验机测试了钎焊接头的力学性能。结果表明,基材表面锡镀层结晶晶粒呈现明显的(200),(112)择优取向。BAg34CuZnSn基材钎料和5.0%Sn含量镀锡银钎料连接的316LN不锈钢钎焊接头组织主要由Ag相、富Cu相、CuZn相、Cu_5Zn_8相组成;当镀锡银钎料中Sn含量为6.4%时,316LN不锈钢钎焊接头组织主要由Ag相、富Cu相、CuZn相、Cu_5Zn_8相、Cu_(41)Sn_(11)相和Ag_3Sn相组成。镀锡后316LN不锈钢钎焊接头的抗拉强度高于基材钎料连接的接头强度,且随着镀锡银钎料中Sn含量逐渐升高,316LN不锈钢钎焊接头的抗拉强度呈现先升高后降低的趋势。在镀锡银钎料中Sn含量为5.5%时,钎焊接头的抗拉强度最高,为415 MPa。镀锡不改变316LN不锈钢钎焊接头的断口特征,镀锡前后316LN不锈钢钎焊接头的拉伸断口均呈现以韧性断裂为主脆性断裂为辅的混合断裂特征。 By brazing the micro-tin layer on the substrate surface of BAg34CuZnSn solder (3.5% Sn, mass fraction), 316LN stainless steel was connected by induction brazing method. The crystal orientation and interface morphology of the tin coating on the substrate surface were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the microstructure, phase composition and fracture morphology of the 316LN stainless steel brazed joint were analyzed. Tensile testing machine tested the mechanical properties of brazed joints. The results show that the crystallized grains on the surface of tin coating show obvious (200), (112) preferred orientation. The microstructure of 316LN stainless steel brazed joint with BAg34CuZnSn substrate solder and 5.0% Sn content tin-plated silver brazing filler metal mainly consists of Ag phase, Cu-rich phase, CuZn phase and Cu_5Zn_8 phase. When Sn content in Sn-plated silver solder is 6.4 %, The microstructure of 316LN stainless steel brazed joints mainly consists of Ag phase, Cu-rich phase, CuZn phase, Cu_5Zn_8 phase, Cu_ (41) Sn_ (11) phase and Ag_3Sn phase. The tensile strength of 316LN stainless steel brazed joint after tin plating is higher than the joint strength of brazing filler metal, and the tensile strength of 316LN stainless steel brazed joint increases first with the increasing of Sn content in tin-plated silver brazing filler metal High and then reduce the trend. When the content of Sn in tin-plated silver brazing filler metal is 5.5%, the tensile strength of braze joint is the highest, 415 MPa. Tinning does not change the fracture characteristics of 316LN stainless steel brazed joints. The tensile fracture of 316LN stainless steel brazed joints before and after tin plating shows mixed fracture characterized by ductile fracture, mainly brittle fracture.