管板单边电阻点焊环状焊点力学性能分析

Mechanical properties of ring nugget in sheet-to-tube joining

电阻点焊接头的焊接强度由母材和熔核的材料属性及几何特征决定。管板单边电阻点焊由于其焊接结构的特殊性,生成熔核的外形为环状,其强度不能用传统的圆形焊点强度经验公式计算。环状熔核的特征影响因素复杂,物理试验存在不确定性,通过大量试验方法难以建立焊接强度和影响因素之间的关系。基于拉剪试验原理,采用计算机模拟试验和试验设计方法,设计试验并统计得出低碳钢焊接强度和环状熔核几何特征因素之间的关系,并对其影响规律做了深入研究,为环状熔核质量的评估提供了依据。

Strength of resistance spot weld is determined by the physical attributes of weldment including material and geometric issues. The strength of the ring nugget in sheet-to-tube single-sided spot welding is different from that of the button nugget in traditional sheet-to-sheet spot welding. And the relationships between strength and attributes of ring nugget are unknown. Meanwhile, the large number of variables and experimental uncertainty also make it difficult to establish this relationships. A numerical simulation experiment was conducted using the concept of design of experiments (DOE) and the method of finite element based on the tensile-shear tests. The mechanical properties during tensile-shear process was analyzed and quantitative relationships were established to link a weld's tensile-shear force and its geometrical attributes, which supplied the proof for the nugget quality estimation.