电源控制模式对镍片微电阻点焊过程的影响

恒流控制模式是电阻焊电源最主要的控制模式，然而该模式在焊接初期能量输入较大，易导致不良焊接现象的发生与能量的浪费。为解决这一问题，文中以薄镍片为焊接对象，研究不同电源控制模式对接头形成过程、接头性能和过程能耗的影响。以抗剪强度作为焊点质量评价指标，采用正交试验研究工艺参数对接头抗剪强度的影响，并获得恒压、恒流和恒功率控制模式下的最优焊接工艺参数；对比研究不同模式下最优焊接工艺参数条件下试样的抗剪强度、熔核尺寸、接头形貌、动态电阻和能量消耗。结果表明，恒流、恒压和恒功率模式下均可获得抗剪强度、表面形貌和熔核尺寸相近的焊接接头，接头形成过程物理特征也相似；然而，恒压控制模式下焊接过程能耗仅为23.73 J，远小于恒流和恒功率模式的过程能耗，在实际生产中具有明显优势。创新点：采用正交试验方法研究了不同电源控制模式下工艺参数对薄镍片微电阻点焊接头性能的影响规律，基于焊接过程电特性曲线对比分析了不同电源控制模式下熔核形成过程，通过焊接过程能耗计算，发现在获得相近接头性能的前提下恒电压控制模式下焊接过程持续时间更短、能耗更低。

Influence of power supply control mode on micro-resistance spot welding process of nickel chip

Constant current control mode is the most important control mode of resistance welding power supply.However, this mode has a larger energy input in the initial stage of welding, which easily leads to the occurrence of bad welding phenomenon and energy waste.In order to solve this problem, the influence of different power control modes on formation process and performance of the joint, and process energy consumption was studied by taking thin nickel sheet as welding object in the paper.Taking shear strength as evaluation index of the joints’ quality, the influence of welding parameters on tensile strength of joints was studied by orthogonal test, and the optimal welding parameters were obtained under constant pressure mode, constant current mode and constant power control mode.The tensile strength, fusion core size, morphology of joints, dynamic resistance and energy consumption of the samples under conditions of optimal welding parameters with different modes were compared and studied.The results showed that the welded joints with similar tensile strength, surface morphology and core size could be obtained under constant current mode, constant pressure mode and constant power mode, and the physical characteristics of formation process of joins were similar.However, the energy consumption of welding process under constant pressure control mode was only 23.73 J, which was far less than that under constant current mode and constant power mode, and it had obvious advantages in practical production.Highlights: Orthogonal test method was used to study the influence of welding parameters on the performance of micro-resistance spot welded joints of thin nickel sheet under different power supply control modes.Based on the electrical characteristic curve of welding process, the formation process of fusion core under different power supply control modes was analyzed.It was found on the premise of obtaining similar joint performance that the welding duration was shorter and energy consumption was lower under constant voltage control mode.