摘要:
研究了热镀锌DP780电阻点焊性能, 并优化其点焊参数。通过测量焊接接头的熔核直径、熔透率、压痕深度, 观察焊接接头显微组织, 检测焊接接头硬度、抗剪力及正拉力等参数, 综合评价热镀锌DP780点焊性能。结果表明:DP780热镀锌板因其合金含量高的特点, 点焊性能良好, 但焊接工艺窗口较窄。当电极压力为3.5 kN, 焊接电流为9.5 kA时, 最佳焊接时间为300~400 ms, 当焊接电流为10.5~1.5 kA时, 焊接时间在200~400 ms均可。DP780热镀锌板点焊接头显微组织为马氏体和铁素体, 这种焊接接头的组织决定了其塑性比仅有8%~0%, 接头硬度值稍高。焊点的失效形式均为熔核剥离失效。
Abstract:
In this paper,the spot weldability of hot galvanizing DP780 had been investigated and the spot welding parameters had been optimized.The spot welding performance of hot galvanizing DP780 had been evaluated by measuring the nugget diameter,penetration rate and indentation depth,observing the microstructure,texting the hardness,detecting the shear force and tensile force of welded joints. The result showed that,the spot welding performance of hot galvanizing DP780 was good because of the high alloy content,while the welding process window was narrow.When the electrode pressure was 3.5 kN,and the welding current was 9.5 kA,the welding time could be selected from 300 to 400 ms.When the welding current was 10.5~11. 5 kA,the welding time could be select from 200 to 400 ms. The microstructure of hot galvanizing DP780 weld joint was composed of martensite and ferrite,resulting in a low plasticity ratio of only 10% ~30% and somewhat high hardness.The failure form of welded spot was melt nugget stripping.
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