Q345双丝CMT焊接工艺研究

Study on Q345 CMT Twin Welding Process

对3 mm厚Q345薄板进行双丝CMT焊接试验,使用光学显微镜对焊接接头的宏微观形貌进行观察,通过拉伸试验和硬度试验测试焊接接头的力学性能。结果表明：焊缝熔宽随着前丝电流的增加先增加后趋于稳定,熔深增加,余高变化不大;随着后丝电流的增加,焊缝逐渐成形均匀,且在200 A后熔宽明显增加,出现蜈蚣脚样缺陷;前丝电流为290 A,后丝电流为180 A时能够获得优良的焊接接头,有较高的力学性能,拉伸试样在母材处断裂;接头的硬度随着距焊缝中心距离的增加而减小。

The CMT twin welding tests of 3 mm thick Q345 sheet were carded out. The macro morphology,microstructttre of the welded joint were observed by using optical microscope, and the mechanical properties of the welded joint were tested through tensile test and hardness test. The results show that with the increase of the front wire current, the weld width increases firstly then becomes stable, the penetration increases and the reinforcement has little change. With the increase of the rear wire current, the weld forms evenly gradually, and the weld width increases obviously above 200 A and the centipede foot defects appear. While the front wire current is 290 A and the rear wire current is 180 A, good welded joint with high mechanical properties can be obtained, and the tensile sample breaks at the base metal. The hardness of the welded joint decreases with the increase of the distance from the weld center.