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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 μ时可获得合适的抗弯强度
In this study, three different brazing alloys (W40, BAg-1, BAg3S) were used to weld the mild steel saw blade substrate and the bronze-based sintered tips. Welding experiments were performed using a DIEXCorp SAB7 high-frequency induction welding machine. The weld width, porosity and porosity of welded zone under different welding temperature and time conditions were studied by means of OLM, SEM, EDS and XRD. The microstructure was evaluated. In order to evaluate the weld strength, a flexural strength (torque) test was also conducted. Welding temperature has a greater impact on weld strength. For the matching welding of bronze base and saw blade steel substrate, the reasonable welding temperature is 70 0 ~ 850 ℃. Welding zone reaction degree, porosity and weld width of three factors affect the welding strength. The reaction zone is formed near the junction of the bronze-based tool head, which adversely affects the weld strength due to the Cu-rich phase, Cu5.6Sn, CuZn4, β (CuZn) and CdAg phases formed in this zone. As the welding temperature increases and the welding time increases, the porosity increases. When the porosity of the weld zone is less than 3 ~ 5%, then the bronze-based tool head will get the best strength. Weld width greater than 30 μ can be obtained when the appropriate bending strength