6082铝合金激光填丝焊热影响区的软化现象

Softening Phenomenon of Heat-Affected Zone in Laser Welding of 6082 Al Alloys with Filler Wire

采用激光填丝焊方法焊接了6082铝合金,研究了焊接速度对焊接接头热影响区软化的影响。结果表明,当温度为430～560℃时,接头热影响区会发生明显的β″强化相溶解,β″相的数量明显减少,接头的硬度和拉伸强度减小,发生了热影响区的深度软化效应,热影响区的软化区成为接头最薄弱的区域。当激光功率为4250 W,焊接速度为2.7 m·min^(-1)时,接头热影响区的局部深度软化现象得到有效抑制,其平均硬度值大于82 HV,抗拉强度增大至249 MPa,接头的拉伸断裂发生于焊缝。

The laser welding of 6082 Al alloys with filler wire is conducted and the influence of the welding speed on the softening of the heat-affected zone （HAZ） of the welding joints is investigated. The results show that, the obvious dissolution of β＇＇ reinforced phases in the HAZ occurs when the temperature is between 430℃ and 560 ℃. The number of β＇＇ phases decreases substantially and thus the hardness and the tensile strength of these joints decrease. This deep softening effect of the HAZ occurs and the softening area of the HAZ becomes the weakest one of these joints. At a laser power of 4250 W and a welding speed of 2.7 m · min^-1, the local deep softening phenomenon of the HAZ can be effectively suppressed. The average hardness is larger than 82 HV, the tensile strength increases up to 249 MPa, and the tensile fractures occur in welds.