摘要
以Q235低碳钢为材料,研究了光束扫描对激光热丝焊的焊缝成形特性、微观组织和力学性能的影响。结果表明:在扫描激光的作用下,焊缝的成形变得更加均匀,飞溅减少,焊缝熔深减小,熔宽增大,截面熔合区底部变得更加平滑;扫描激光的加入降低了熔池的温度梯度,抑制了粗大柱状晶的生长,改变了铁素体晶粒形态,细化了熔合区组织,提高了焊缝韧性及延伸率;扫描激光促进了焊缝成分的均匀化分布,抑制了偏析,降低了熔合区显微硬度。由于激光作用面积增大等因素,光束扫描增强了激光热丝焊接对间隙的桥接能力。
Objective Laser welding has the characteristics of a high energy density,low heat input,and high welding efficiency;however,conventional laser welding has a small focused spot and high requirements for the welding assembly gap.To solve this problem,scholars have developed laser wire filling welding technology.Based on this,some scholars have developed laser hot wire welding technology,which can effectively improve the absorptivity of the welding wire by preheating the welding wire in advance,reduce the requirements for laser power,and improve the welding speed;however,there are still problems such as high requirements for the alignment of the laser focus and the tip of the welding wire,and an uneven weld height.In this study,the process characteristics of Q235 steel by scanning laser hot wire welding are systematically studied,and the mechanism of the influence of the scanning laser on the solidification process of weld metal is clarified,which provides technical guidance for expanding the industrial application of laser welding.Methods The base material used in this study is the Q235 steel plate.The size is 50 mm×120 mm×2 mm,and the structure is massive ferrite at normal temperature.The flat surfacing welding method is used in the research on the weld surface and section forming.The docking method is adopted in the study of the microstructure and properties of welded joints.According to the previous research and accumulation of this research group,the fixed wire feeding method is front wire feeding,the tilt angle of the welding torch is 45°,and the laser focus is located on the surface of the plate,that is,the defocus quantity is 0 mm.In the welding process,the shielding gas is argon with purity(volume fraction)greater than 99.99%.The gas pipe angle is 60°and the gas flow rate is approximately 20 L/min.In the butt welding experiment,the fixed laser power is 1.8 kW,the welding speed is 1.0 m/min,the preheating current of laser cold wire welding is 0 A,the preheating current of laser hot wire welding is 100 A,
作者
于宸乾
任刚
黄映杰
高明
Yu Chenqian;Ren Gang;Huang Yingjie;Gao Ming(Wuhan National Laboratory for Optoelectronics,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China;Jiujiang Institute of Advanced Laser Technology,Jiujiang 332005,Jiangxi,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2024年第12期50-58,共9页
Chinese Journal of Lasers
基金
国家自然科学基金(52275335)
江西省重点研发计划(20212BBE51011)
中国博士后科学基金(2023M731173)。
关键词
激光技术
激光热丝焊接
光束扫描
微观组织
力学性能
laser technique
laser hot wire welding
laser beam scanning
microstructure
mechanical properties
