采用Ag-Cu-Zn-Cd焊料焊接烧结刀头与低碳钢的焊接特性

Brazing Characteristics between Sintered Segment and Mild Steel Using Ag-Cu-Zn-Cd Filler

该项研究中采用三种不同焊料 (W 4 0 ,BAg - 1,BAg3S)对低碳钢锯片基体和青铜基烧结刀头进行焊接。使用DIEXCorp(迪爱克斯公司 )SAB7型高频感应焊接机进行焊接实验。利用OLM(金相分析 ) ,SEM(扫描电子显微镜 ) ,EDS(能谱分析 )和XRD(X射线衍射分析 )等手段对不同焊接温度与时间条件下焊接区的焊缝宽度、气孔率和显微结构进行了评价。为了评价焊接强度 ,还进行了抗弯强度 (扭矩 )测试。焊接温度对焊缝强度有较大影响。对于青铜基刀头和锯片钢基体的匹配焊接 ,其合理的焊接温度为 70 0～ 850℃。焊接区的反应程度 ,气孔含量和焊缝宽度三个因素影响焊接强度。在青铜基刀头靠近接面处形成反应区 ,由于在该区形成富Cu相 ,Cu5.6Sn ,CuZn4 ,β(CuZn)和CdAg相 ,而对焊接强度产生有害影响。当焊接温度提高 ,焊接时间增加 ,则气孔率将增大。当焊缝区气孔率小于 3～ 5%时 ,则青铜基刀头将获得最佳强度。焊缝宽度大于 30

In this work, shank(mild steel) and sintered bronze base tips were brazed with three different filler materials(W 40, BAg1 and BAg3S). A high frequency induction brazing equipment(SAB7, DIEX Corp) was used for brazing experiments. The joint thickness, porosities and microstructures of brazed region with various conditions (brazing temperature, holding time) were evaluated with OLM, SEM, EDS and XRD. Bending (torque) test was also performed to evaluate strength of the brazed joints. the brazing temperature had a strong influence on the joint strength, and the optimum brazing temperature range was found to be about 700℃～850℃ for the bronze/steel combinations. The strength of the brazed joint was formed in the bronze base tip adjacent to the faying surface, and affected detrimental influence on the strength due to the formation of Cu rich phases, Cu 5.6 Sn, CuZn 4, β(Cuzn) and CdAg. Porosities increased as brazing temperature and holding time increased, and the brazed joints with porosities of less than about 3～5% had an optimum strength for the bronze base tip. The brazed joint with joint thickness of higher than about 30μ an revealed acceptable torque strength.