高速列车用厚板铝合金CMT焊接工艺

针对低热输入、高质量焊接技术的需求,研究厚板铝合金多层多道冷金属过渡技术(cold matal transter,CMT)焊接工艺和脉冲MIG焊接工艺的区别,对CMT焊接和脉冲MIG焊接进行热循环曲线测量,焊接接头拉伸、弯曲、硬度等常规力学性能试验和接头微观组织分析.结果表明,铝合金厚板焊接时相对脉冲MIG焊接方法,CMT方法焊接温度场低,焊接接头软化明显减弱,冲击韧性得到提高,厚板多层多道焊接接头组织明显改善,晶粒明显细化.试验表明CMT焊接方法可获得相对脉冲焊接更加优良的铝合金焊接接头.

CMT welding technology of thick aluminum alloy plates for high speed train

For the demand of low heat input and high quality welding technology, the difference in multi-pass welding techniques for thick aluminum alloy plates with CMT welding and pulse MIG welding was investigated. The thermal cycles during welding were measured; the microstructure and mechanical properties (tensile, bending and microhardness) of the welded joint were analyzed. The tests show that comparing to pulse MIG welding, CMT welding technology could make weld with lower temperature field, decrease the softened zone, increase the impact toughness of the joint, and improve the weld microstructure significantly. The experimental results show that CMT welding can make better weld on thick aluminum alloy plate.