基于PLC控制的Q890D钢/AZ91镁合金MIG对接焊接头组织与性能研究

Microstructure and Mechanical Properties of MIG Butt Welding Joint of Q890D Steel/AZ91 Magnesium Alloy Based on PLC Control

采用熔化极气体保护焊对Q890D钢和AZ91镁合金异种金属板进行了对接焊试验,研究了焊接电流和焊接速度对接头成形、显微组织和力学性能的影响。结果表明,焊接速度为35 cm/min时,随着焊接电流增加,焊缝区平均晶粒尺寸不断增大,界面层厚度增加,接头抗拉强度呈现先增加而后降低的趋势,在焊接电流为85 A时焊缝成形较好,且具有较高的强度;焊接电流为85 A时,随着焊接速度增大,焊缝区平均晶粒尺寸不断减小,界面层厚度减小,焊接接头抗拉强度呈现先增加而后降低的趋势,焊接速度为45 cm/min时焊缝成形较好,且具有较高的强度。

The butt welding tests of Q890D steel and AZ91 magnesium alloy dissimilar metal plates were carded out by using melting inert gas shielded welding, and the effects of welding current and welding speed on the joint forming, microstructure and mechanical properties were studied. The results show that when the welding speed is 35 cm/min, with the increase of welding curreent, the average grain size of weld zone gradually increases, the thickness of interface increases and the tensile strength of welded joint increases firstly and then decreases. The weld forming is good with welding current of 85 A, and the strength of the joint is high. When the welding current is 85A, with the increase of weldingspeed, the average grain size of weld zone gradually decreases, the thickness of interface decreases and the tensile strength of welded joint increases firstly and then decreases. The weld forming is good with welding speed of 45 cm/min, and the strength of the joint is high.