送丝速度对铝/钢激光熔钎焊接头组织与性能的影响

Effect of Wire Feeding Speed on Microstructure and Properties of Laser Welding-brazing Joint of Aluminum/Steel

采用ER2319焊丝进行了6061-T6铝合金/Q235镀锌钢光纤激光熔钎焊接,分析了送丝速度对接头成型、显微组织与力学性能的影响。结果表明:当激光功率为1.2 kW,焊接速度为1.2 m/min时,送丝速度在1.2~3.0 m/min范围内均可获得有效接头。接头的抗拉强度随着送丝速度的增加呈现先上升后减小的趋势,当送丝速度为2.4 m/min时平均抗拉强度达到最大值,为116.15 MPa。当送丝速度为1.8、2.4 m/min时,接头的上下表面的金属间化合物层可控制在10μm以内,而对接界面处的金属间化合物层厚度随着送丝速度的改变变化不明显,对接界面的IMC层主要由FeAl、FeAl_(2)、Fe_(4)Al_(13)相组成。接头的断裂形式为典型的解理断裂模式,而位于润湿铺展在钢表面的铝合金处则为韧性断裂。

The laser welding-brazing experiment of 6061-T6 aluminum alloy/Q235 galvanized steel dissimilar metal was carried out with ER2319 wire as filler metal,and the effect of wire feeding speed on the joint forming,microstructure and mechanical properties was studyed.The results show that when the laser power is 1.2kW,the welding speed is 1.2 m/min and the wire feeding speed is 1.2-3.0 m/min.,effective joints can be obtained.The tensile strength of the joint increases firstly and then decreases with the increase of the wire feeding speed.When the wire feeding speed is 2.4 m/min,the average tensile strength reaches the maximum value,which is 116.15MPa.When the wire feeding speed is 1.8 and 2.4 m/min,the intermetallic compound layer on the upper and lower surface of the joint can be controlled within 10μm.However,the thickness of intermetallic compound layer at the butt interface does not change significantly with the change of wire feeding speed.The IMC layer in the joint consists of FeAl,FeAl_(2) and Fe_(4)Al_(13) phases.The fracture form of the joint is a typical model of cleavage fracture,while it is ductile fracture at the aluminumalloy position on the steel surface.