采用1 kW Nd∶YAG激光器焊接2 mm厚H62黄铜和20#钢管材。聚焦激光作用在接头黄铜一侧形成深熔焊接熔池,熔化的黄铜浸润碳钢界面形成接头。因此,在焊缝的黄铜一侧为深熔焊,碳钢一侧为钎焊,这一方法称为激光深熔钎焊(LPB)。采用光学显微镜、扫描电镜(SEM)和X射线能谱分析(EDS)对焊缝成形和接头界面进行观察,发现黄铜母材与焊缝界面是正常的激光深熔焊特征,同时碳钢母材与焊缝的界面形成了良好的冶金结合,相互作用区的宽度约为3 μm。显微硬度结果表明焊缝硬度值高于黄铜母材。经爆破实验测试,断裂发生在黄铜一侧,表明H62黄铜-20#钢激光深熔钎焊接头力学性能满足工业使用要求。

A continuous wave (CW) Nd∶YAG laser with a output power of 1 kW was used to join H62 brass and 20# low carbon steel with a thickness of 2 mm. The focused laser beam with a diameter of 0.3 mm was irradiated at the brass side of the butt joint. Thus the brass was penetratingly melted and interacted with the solid steel to form a brazing joint. The brass is penetratingly welded, and the low carbon steel is brazed. This process is called laser penetration brazing (LPB). The interfacial characterizations of the joint were investigated by metallographic microscope, scanning electron microscope (SEM) and energy dispersive X-ray spectroscope (EDS). The results show that the element diffusion and solution occur and metallurgical bonding is achieved between brass and steel. The width of the interaction layer is about 3μm. The brass weld is harder than that brass substrate and the failure occurs at the brass substrate but weld judged from the data of bursting test. The mechanic performance of H62 brass and 20# low carbon steel butt joint by laser penetration brazing can meet the demand of industrial application.