镀锡银钎料钎焊316LN不锈钢的接头组织及力学性能

发布时间：2018-11-07 10:33

【摘要】：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。
[Abstract]:By brushing micron tin layer on the surface of BAg34CuZnSn solder (3.5SnC, mass fraction), the 316LN stainless steel was connected by induction brazing. Scanning electron microscopy (SEM) and X-ray diffractometer (XRD) were used to analyze the crystalline orientation and interface morphology of tin coating on the substrate surface, as well as the microstructure, phase composition and fracture morphology of 316LN stainless steel brazed joint. The mechanical properties of brazed joints were tested by universal tensile testing machine. The results show that the crystalline grain of tin coating on the substrate is (200), (112) preferred. The microstructure of the 316LN stainless steel brazing joint connected by BAg34CuZnSn base metal and 5.0%Sn silver solder is mainly composed of Ag phase, rich Cu phase and CuZn phase. Cu_5Zn_8 phase composition; The microstructure of 316LN stainless steel brazed joints is mainly composed of Ag phase, rich Cu phase, CuZn phase, Cu_5Zn_8 phase, Cu_ (41) Sn_ (11) phase and Ag_3Sn phase when the content of Sn in the solder is 6.4. The tensile strength of 316LN stainless steel brazed joint after tin plating is higher than that of base solder joint, and the tensile strength of 316LN stainless steel brazed joint increases first and then decreases with the increase of Sn content in tinned silver solder. The tensile strength of the brazed joint was the highest when the Sn content in the silver plated solder was 5.5 MPa. the tensile strength of the brazed joint was 415 MPa.. Tin plating did not change the fracture characteristics of 316LN stainless steel brazing joints. The tensile fracture of 316LN stainless steel brazed joints before and after tin plating showed mixed fracture characteristics with ductile fracture as the main brittle fracture.
【作者单位】：华北水利水电大学机械学院;哈尔滨工业大学先进焊接与连接国家重点实验室;郑州机械研究所新型钎焊材料与技术国家重点实验室;
【基金】：国家自然科学基金项目(51705151) 河南省自然科学基金项目(162300410191) 河南省高等学校重点科研项目(17A430021)资助
【分类号】：TG457.11

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