焊接工艺参数对5383铝合金搅拌摩擦焊接头耐腐蚀性的影响

Effect of Welding Parameters on Corrosion Resistance of 5383 Al Alloy Friction Stir Welding Joint

在制备不同焊接工艺条件下的5383铝合金搅拌摩擦焊接头的基础上,利用扫描电镜与能谱分析方法研究搅拌摩擦焊接头典型区域的宏观形貌特征与显微形貌特征,得到焊接速度、搅拌头转速及搅拌头压力等焊接工艺参数对接头耐腐蚀性的影响规律,结果表明:在特定的焊接工艺条件下,焊缝区域会产生S线。S线是接头腐蚀最严重的区域,其原因是由Mg元素偏聚、大量微孔的聚集与锰铁化合物的形成等三方面因素造成的;除S线及其附近区域外的焊缝其他区域的耐腐蚀性优于母材。同时,分析三种因素导致焊接接头耐腐蚀性降低的原理,阐述不同焊接工艺参数对5383铝合金搅拌摩擦时接头中S线形成的影响,提出利用减少焊接速度、增加搅拌头转速与提高搅拌头压力的方法来改善5383铝合金搅拌摩擦焊接头的耐腐蚀性。

On the basis of preparing the friction stir welding joint of 5383 Al alloy under different welding conditions,the macrocosmic appearance and the microcosmic appearance are all researched,and the effects of welding parameters,such as welding speed,stirring head speed and pressure,on the corrosion resistance of joint are obtained.The results show that the ＂S＂ line appears in the weld zone under certain welding conditions.The most serious region of corrosion is the ＂S＂ line,which results from three factors： the segregation of Mg,the aggregation of many micropores,and the formation of ferromanganese compounds.The corrosion resistance of weld zone other than ＂S＂ line and its nearby regions is better than that of the parent metal.Moreover,the reasons why the three factors make the corrosion resistance decrease are analyzed.The effects of different welding parameters on the ＂S＂ line are described.Decreasing the welding speed,increasing the stirring head speed and pressure can improve the corrosion resistance of friction stir welding joint of 5383 Al alloy.