热镀锌双相钢与普通热镀锌钢点焊工艺对比

Comparative research on spot welding technology for high-strength dual-phase galvanized steel and traditional galvanized steel

用单因素法对比试验了两种基板材料不同的热镀锌钢板的点焊工艺。研究焊接电流、焊接时间和电极压力三个主要工艺参数对点焊质量的影响。结果表明，80kg级热镀锌双相铜点焊工艺参数比普通热镀锌铜窄很多，普通镀锌钢接头抗拉剪载荷只有双相铜的1／3～1／2；焊接电流和焊接时间对焊点的熔核直径和接头抗拉剪载荷影响很大．电极压力对接头抗拉剪载荷和熔核直径影响甚小。变化幅度仅在500～1000N和0．5mm以内。数据分析表明，以熔核直径为判据优化焊接参数时，抗拉剪载荷波动较大．可能出现强度偏低的情况，为此提出了以抗拉剪裁荷为判据进行参数优化的方法，得到0．8mm厚普通热镀锌钢点焊参数范围：焊接电流10～12．5kA，焊接时间16-23cyc，电极压力1430～3570N；1mm厚80kg级热镀锌双相钢点焊参数范围：焊接电流10．7～11．7kA，焊接时间13～19cyc，电极压力2150—3200N、

Based on the method of single-factor,two different hot-dip galvanized steel sheets were tested in the experiments. The effect on spot-welding quality of three main welding parameters-welding eun＇ent,welding time and electrode pressure were confirmed. The result was as followed： contrasting to general galvanized steel,the variation range of welding parametem of 80kg level highstrength dual-phase galvanized steel was comparatively narrow, while tensile-shear strength of general galvanized steel was only 1/3 to 1/2 of it. Nugget diameter and tensile-shear strength were sensitive to the variation of current and welding time ,but insensitive to electrode pressure,the variation range of them were within 500 to 1 000 N and 0.5 mm. Data analysis indicated that if parameters optimization based on the criterion of nugget diameter,the tensile-shear strength fluctuated widely and might lead to strength deficiency. Consequently this article puts forward a criterion based on tensile-shear strength to optimize the parameters,the range of improved parameters was obtained： welding current from 10.5 to 11.7 kA,welding time from 12 to 19cyc and electrode pressure from 2150 to 3200N for 0.8mm general galvanized steel; welding current from 10 to 12.5 kA,welding time from 16 to 23cyc and electrode pressure from 1430 to 3570N for Innn 80kg level high-strength dual-phase galvanized steel.