铝合金车身板材焊缝组织缺陷分析

Analysis of weld microstructure defects of aluminum alloy body plate

铝合金材料是当前汽车车身板材制作的主要材料,但在板材过厚的条件下,易形成飞边、气孔以及未焊合等缺陷,严重时将威胁汽车行驶安全,因此分析铝合金车板板材焊缝组织缺陷。在明确铝合金车身板材的焊接性能基础上,选取型号为EN-AW6005A-T6、EN-AW5083A-H111以及EN-AW6082-T6的铝合金材料作为母材,采用盘状MIG焊焊丝和棒状TIG焊焊丝和带锥形螺纹搅拌针的焊具,根据相应的工艺要点完成铝合金车身板材焊接。分析不同焊缝组织缺陷得到以下结论:孔洞缺陷形成的主要原因是焊缝中、下部材料塑性流动较差;铝合金车板板材表层过度软化是导致飞边缺陷形成的主要原因;未焊合发生在焊缝底部,其产生原因是焊接热输入不足,焊缝底部再结晶程度低;焊核区底部焊缝组织显微硬度值较低,而顶部值相对较高。

Aluminum alloy material is the main material for the production of automobile body plate at present,but when the plate is too thick,it is easy to form defects such as flash,air hole and non welding,which will seriously threaten the driving safety of automobile.Therefore,the weld microstructure defects of aluminum alloy plate were analyzed.On the basis of clarifying the welding performance of aluminum alloy body plate,the aluminum alloy materials with models of en-aw6005 a-t6,en-aw5083 a-h111 and en-aw6082-t6 were selected as the base metal,and the welding of aluminum alloy body plate was completed according to the corresponding process points by using disk MIG welding wire,rod TIG welding wire and welding tool with conical thread stirring needle.The conclusions were as follows:the main reason for the formation of hole defects was the poor plastic flow of materials in the middle and lower parts of the weld.Excessive softening of the surface layer of aluminum alloy turning plate was the main reason for the formation of flash defects.Non welding occurs at the bottom of the weld,which is due to insufficient welding heat input and low recrystallization at the bottom of the weld.The microhardness value of the weld structure at the bottom of the nugget zone was low,while the value at the top was relatively high.