焊接电流对镀铝锌钢板点焊接头组织的影响

Influence of Welding Current on Microstructure of Al-Zn Alloy Coated Steel Sheet Spot Welding Joint

在相同的电极压力和焊接时间下,通过改变焊接电流对0.8 mm的镀铝锌钢板进行点焊试验,分析了焊接电流对镀铝锌钢板点焊接头组织的影响。结果表明：焊接时间为14 cyc,焊接压力为2400 N,焊接电流不大于7.0 kA时易形成未熔合现象。所有焊点熔核区的组织为贝氏体、马氏体及少量的珠光体和铁素体;晶粒形态主要为柱状晶粒,随着电流的增大,柱状晶粒变得更粗大,方向性更强。电流在8.5、9.0 kA时,焊核区有少量等轴晶粒,焊点质量较好。

Under the same electrode pressure and welding time, the spot welding tests of 0.8 mm Al-Zn alloy coated steel plate were carried out by changing welding current, and the influence of welding current on the microstructure of spot welded joint of Al-Zn alloy coated steel plate was analyzed. When the welding time is 14 cyc, the welding pressure is 2400 N, and the welding current is no more than 7 kA, it is easy to form non fusion phenomenon.The microstructure of nugget zone of all spot welding joints is bain/te, martensite and a small amount ofpearlite and ferrite. The grain shape is mainly columnar grain, with the increase of current, the columnar grain becomes coarser and more directional.When the current is 8.5,9.0 kA, there is a small amount of equiaxed grain in the nugget zone, and the quality of the solder joint is good.