以Q235钢为母材进行手工自蔓延立焊试验，并利用接头拉伸性能测试、SEM、EDS和XRD研究焊接接头的抗拉强度及断口形貌。结果表明，手工自蔓延立焊Q235钢所得焊接接头在进行拉伸测试时，塑性变形不明显，抗拉强度可达367 MPa。断口发现大量均匀细小的等轴韧窝和一定量的撕裂棱，拉伸试样的断裂是韧性断裂与准解理断裂混合的断裂方式。分析焊接接头组织发现，获得的焊缝合金为铜铁镍合金，富铜相与富铁相均匀分布，但由于焊缝合金中富铜相和富铁相的界面结合比熔合区与热影响区界面结合差，进行拉伸试验时在焊缝合金区断裂。%The base metal of Q235 was welded by manual self-propagating high-temperature synthesis (SHS) vertical weld. Tensile strength and fracture microstructure of joints were studied by tensile testing, XRD, SEM and EDS. The results show that tensile strength of the joint is 367 MPa, but plastic deformation of joints by manual SHS vertical weld is not obvious in the tensile testing. A large amount of uniform, fine and equiaxial dimple and a small quantity of tear ridge appear in the fracture of weld alloy zone. And the fracture of tensile testing is a mix of dimple fracture and quasi-cleavage fracture. The analysis of weld microstructure indicates that weld is constituted by uniform distribution of Fe-rich phase and Cu-rich phase, which are both comprised of Cu-Fe-Ni alloy. Interfacial bonding between Fe-rich phase and Cu-rich phase in weld alloy is poorer than that between the fusion zone and the heat affected zone, and fracture occurs in the weld alloy during the tensile testing.
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