镀铜和无镀铜焊丝Q345E低合金钢焊接接头组织与疲劳性能研究

镀铜和无镀铜焊丝Q345E低合金钢焊接接头组织与疲劳性能研究 Research on microstructure and fatigue properties of copper-plated and non copper-plated Q345E low alloy steel welded joint 孙逸凡 SUN Yifan 1 first-author 许鸿吉 XU Hongji 1 蔺博 LIN Bo 1 大连交通大学 大连交通大学 Dalian Jiaotong University Dalian Jiaotong University 使用镀铜和无镀铜焊丝焊接Q345E低合金钢,观察其显微组织,并对其焊接接头进行脉动拉伸疲劳试验,扫描断口形貌。结果表明:两种焊接接头的显微组织相似,无镀铜焊丝Q345E低合金钢焊接接头过热区无碳贝氏体较多。无镀铜焊丝Q345E低合金钢焊接接头疲劳性能略低,但两种焊接接头疲劳性能相差不大,余高的存在明显降低疲劳极限。断口微观形貌可以看出:断口无明显缺陷,断口平整能看到清晰的启裂源,扩展区裂纹生长,终断区形貌为大小深浅不一的韧窝,为韧性断裂。 Q345 E low alloy steel was welded by copperplated welding wire and non copper-plated welding wire.Microstructure is observed and a pulsating tensile fatigue test is conducted on its welded joints,and the fatigue fracture is scanned and analyzed. The results show that microstructure of the two kinds of welded joints are similar,and there are more carbon-free bainites in the overheated zone of Q345E low alloy steel welded joint welded by non copper-plated welding wire. The fatigue property of Q345E low alloy steel welded joint welded by non copper-plated welding wire is slightly lower,but the difference between the two kinds of welded joints is not significant and the presence of reinforcement significantly reduces the fatigue limit. The microscopic appearance of the fracture shows that the fracture has no obvious defects, the fracture surface is smooth and the source of crack initiation is clear. The crack grows in the propagation zone,and the morphology of the final fracture zone is dimple with different sizes and depths,which is ductile fracture. Q345E低合金钢 镀铜焊丝 无镀铜焊丝 显微组织 疲劳性能 Q345E low alloy steel copper-plated welding wire non copper-plated welding wire microstructure fatigue properties TG407 2022-03-08 11 50