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采用电弧辅助激光焊接方法通过添加Al-12%Si焊丝进行了铝/镀锌钢异种金属涂粉对接熔钎焊工艺试验,分析了送丝速度对焊缝成形的影响;运用光学显微镜、扫描电子显微镜、X射线衍射仪、材料试验机等观察分析了焊接接头各区域的微观组织、断口形貌、物相成分和接头力学性能。结果表明:在适当的焊接参数和工艺条件下,能够得到正反面成形良好的对接接头。当焊接速度一定时,随着送丝速度的增大,焊缝正面的铺展宽度减小,背面的铺展宽度增大。Si元素主要富集在接头上部,焊缝中的组织主要有α(Al)基体及沿晶界分布的Al-Si共晶相。铝/钢界面层生成了不均匀的金属间化合物层,其主要物相有Al_8Fe_2Si、Fe_4Al_(13)和Fe_2Al_5,接头最大抗拉强度可达130 MPa,断口表面形貌呈现韧性和脆性共存的混合型断裂特征。
The arc-assisted laser welding method was used to test the welding process of aluminum / galvanized steel dissimilar metal coated butt-joint by Al-12% Si welding wire. The influence of wire feeding speed on the weld formation was analyzed. Using optical microscope, scanning electron Microscope, X-ray diffractometer and material testing machine were used to observe and analyze the microstructure, fracture morphology, phase composition and mechanical properties of welded joints. The results show that under the proper welding parameters and process conditions, the butt joint with good shape can be obtained. When the welding speed is constant, as the wire feeding speed increases, the spreading width of the weld front decreases and the spreading width of the back increases. The Si elements are mainly enriched in the upper part of the joint. The microstructure of the weld mainly includes α (Al) matrix and Al-Si eutectic phase distributed along grain boundaries. The heterogeneous intermetallic compound layer was formed on the aluminum / steel interfacial layer. The main phase of the intermetallic compound layer was Al_8Fe_2Si, Fe_4Al_ (13) and Fe_2Al_5. The maximum tensile strength of the joint was up to 130 MPa. The morphology of the fracture surface presented the coexistence of ductility and brittleness Type fracture characteristics.