ER50-6焊丝激光焊接Q345B/304异种钢接头组织与性能

目的 研究异种钢激光填丝焊接工艺对焊接组织与性能的影响规律，以降低Q345B/304异种钢激光焊接的成本，扩大异种钢激光焊接的应用范围，使其能够满足使用要求，实现Q345B/304异种钢激光焊接低成本的产业化应用。方法 采用便宜的ER50-6碳钢焊丝代替价格高昂的ER308L不锈钢焊丝以及不锈钢药芯焊丝对Q345B/304异种钢进行激光焊接，主要采用填丝ER50-6焊丝对5 mm厚的Q345B/304异种钢板进行激光焊接，再结合焊缝区、熔合区及热影响区的纳观-微观-宏观多尺度表征和测试结果，研究不同工艺参数下焊接接头的组织与结构，同时结合焊接工艺参数和多尺度的表征结果，研究焊接接头硬度、焊缝中元素分布、物相特征、力学性能的变化规律。结果 当激光功率为4.5 kW、焊接速度为6 mm/s、焊丝直径为1.2 mm、装配间隙为1 mm、送丝速度为2.5 m/min时，焊缝成形最好，且在焊缝中没有出现大量的M23C6和σ等有害相，焊接接头的力学性能等也完全满足使用要求。结论 采用ER50-6焊丝对Q345B/304异种钢进行激光焊接，能够得到完全符合质量要求的焊接接头，且降低了焊接成本。

Structure and Properties of Q345B/304 Dissimilar Steel Joint Using ER50-6 Welding Wire Laser Welding

The work aims to explore the impact of laser wire filling welding process on the welding structure and property of dissimilar steel, reduce the cost of Q345B/304 dissimilar steel laser welding, expand the application range of dissimilar steel laser welding, and enable it to meet usage requirements, so as to achieve low-cost industrial application of Q345B/304 dissimilar steel laser welding. Cheap ER50-6 carbon steel welding wires rather than expensive ER308L stainless steel welding wires and stainless steel flux cored welding wires were used for laser welding of Q345B/304 dissimilar steel plates. Wire filled ER50-6 welding wires were mainly used for laser welding of 5 mm thick Q345B/304 dissimilar steel plates. Then combined with the nanoscale, microscale, and macroscopic characterization and testing methods for the weld zone, fusion zone, and heat affected zone, the organization and structure of welded joints under different process parameters were studied. At the same time, combined with the welding process parameters and multi-scale characterization results, the changes in hardness value, element distribution in the weld seam, phase characteristics, and mechanical properties of welded joints were studied. As a result, when the laser power was 4.5 kW, the welding speed was 6 mm/s, and the diameter of the welding wire was 1.2 mm, the assembly gap was 1 mm, and the wire feeding speed was 2.5 m/min, the weld had the best shape, and there were no detrimental phases such as M23C6 and σ in the weld seam. The mechanical properties of the welded joint also fully met the usage requirements. The results indicate that ER50-6 welding wire can be used for laser welding of Q345B/304 dissimilar steel, which can obtain fully qualified welding joints and reduce welding costs.