Ag含量对硬质合金/钢钎焊接头组织与性能的影响  

Effect of ag content on the microstructure and properties of cemented carbide/steel dissimilar metal high frequency grazing joint

作　　者：赵磊 程志 高华 李炎秋 张小军 任瑞铭[2] ZHAO Lei;CHENG Zhi;GAO Hua;LI Yanqiu;ZHANG Xiaojun;REN Ruiming(CRRC Qishuyan Institute Co.,Ltd.,Changzhou,Jiangsu 213011,China;Dalian Jiaotong University,Dalian,Liaoning 116021,China)

机构地区：[1]中车戚墅堰机车车辆工艺研究所股份有限公司,江苏常州213001 [2]大连交通大学,辽宁大连116021

出　　处：《轨道交通材料》2024年第1期13-21,共9页MATERIALS FOR RAIL TRANSPORTATION SYSTEM

摘　　要：为研究不同Ag含量对硬质合金/钢异质金属高频钎焊接头组织与性能的影响,分别采用BAg50CuZnCd(Ag50)、BAg40CuZnCdNi(Ag40)、BAg30CuZnCd(Ag30)钎料对YG16/35CrMo异质金属进行了高频钎焊,并采用光学显微镜(OM)、扫描电镜(SEM)并结合能谱分析(EDS)对接头的显微组织及物相进行了观察,采用显微硬度仪和拉伸试验机对不同接头显微硬度及剪切性能进行了检测和对比分析。结果表明,采用不同Ag含量的Ag基钎料均实现了硬质合金/钢异质金属的高频钎焊连接,钎料润湿铺展效果较好。Ag50钎料接头焊缝主要由(Ag(s,s)+Cu(s,s))共晶组成,Ag40钎料接头焊缝组织主要由块状Cu(s,s)及(Ag(s,s)+Cu(s,s))共晶组织组成,且随着Ag含量的持续降低,块状Cu(s,s)含量增多。接头显微硬度表明,由于采用Ag基钎料钎焊温度较低,硬质合金与钢母材受热影响较小,显微硬度变化不大。但随着Ag含量的降低,焊缝中心块状Cu基固溶体含量的增加,显微硬度也随之提升。Ag50与Ag40钎料接头剪切强度较高,分别达到245 MPa和237 MPa,Ag30钎料接头由于钎缝中Cu(s,s)含量增加,钎缝协调变形能力降低,导致硬质合金/钎缝侧焊后即出现裂纹,接头剪切强度较低,仅达到149 MPa。硬质合金/钎缝界面由于较大的脆性,成为断裂时的薄弱区域。To study the effect of different Ag content on the microstructure and properties of cemented carbide/steel dissimilar metal high frequency brazing joint,BAg50CuZnCd(Ag50),BAg40CuZnCdNi(Ag40),and BAg30CuZnCd(Ag30)filler metals were employed to conduct high-frequency induction brazing of YG16 cemented carbide and 35CrMo steel.The microstructures and phases of the joints were observed by optical microscopy(OM),scanning electron microscopy(SEM),and energy dispersive spectroscopy(EDS).The microhardness and shear properties of different joints were tested and compared by a microhardness tester and tensile testing machine.The results show that the high-frequency brazing joining of cemented carbide/steel heterogeneous metals was achieved by using Ag-based filler metals with different Ag contents,and the sound wetting and spreading of filler metals on the base metal was achieved.The Ag50 solder seam was mainly composed of(Ag(s,s)+Cu(s,s))eutectic structure,and the Ag40 solder seam was mainly composed of massive Cu(s,s)and(Ag(s,s)+Cu(s,s))eutectic structure.With the continuous decrease of Ag content,the massive Cu(s,s)content increased.The microhardness of the joint showed that due to the low brazing temperature of Ag-based filler metal,the heating effect of cemented carbide and steel base metal was small,and the microhardness changes little.However,with the decrease of Ag content,the content of massive Cu-based solid solution in the center of the weld increased,and the microhardness also increased.The shear strength of Ag50 and Ag40 joints was higher,reaching 245 MPa and 237 MPa,respectively.Due to the increase of Cu(s,s)content in the joint with Ag30 filler,the coordinated deformation ability of the brazing seam was reduced,resulting in cracks after welding of cemented carbide/solder joint,and the shear strength of the joint was lower,only reaching 149 MPa.Due to the brittleness of cemented carbide/brazed joint interface,it becomes a weak area during fracture.

关 键 词：Ag基钎料 高频钎焊 异质金属 显微组织 剪切强度 

分 类 号：U270.41[机械工程—车辆工程]