| As lightweight becom es inevitable trend w ith the rapid developm ent of China auto industry, the application of hi gh strength steel increases gra dually. Also for enhancing the resistance of corrosion, galvanized steel is widely used in vehi cle body. Forming of this high strength galvanized steel is difficult and this causes fitting gap easily. And due to the effect of zinc-layer, streng th defects are easily occu rred during welding process. The use of high strength galvanized steel is restricted by those dif ficulties in m anufacture technology . Therefore, the study of spot welding for high strength galvanized steel has significant meaning with the purpose of improving welding strength.In this paper, high strength galvanized steel B340/590DPD+ZF was used as study object and two experim ents were design ed, one with the f itting gap 0mm and the other with the fitting gap 1mm. Actions f ollowed were us ing ABAQUS f or FEA and valid ating clamping force for eliminating fitting gap with universal tensile test machine. By using the m ethod of dual-pulse welding to eliminate the gap and research the parameters of preheating welding,the boundary of preheating parameters was finally found. This paper also got the change law of electrode abrasion and spot strength, analyzed how dif ference occurred through experiments.By adopting orthogonal experim ent, the paper optim ized welding param eters with two kinds of test pieces, and got two groups of optim ized welding parameters, which im prove shear strength by 10.8% and 5.5%.Finally, this paper discussed how to build inspection system of the welding strength and how to conduct on-site management of the welding strength.The paper conducted experim ents and optim ized welding param eters based on actual production conditions. As a result, the conclusions could have great instructions on production of high strength galvanized steel, as well on-site management of welding strength. |
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