高功率激光焊接船板的组织性能

采用高功率激光进行船板材料的焊接实验。实验条件为:10 kW快轴流CO2激光器和5轴数控机床;船用St370-2低碳钢板;SG填充焊丝;Y型坡口。采用光学显微镜(OM)、扫描电子显微镜(SEM)和X射线衍射仪(XRD)研究了激光焊缝组织和结晶特性,讨论了抑制裂纹生长因素,并进行了焊缝强度实验、硬度实验和X光探伤实验。结果表明,在8～10 kW激光功率和焊速1 m/min参数下,在12 mm厚船板上获得了无裂纹的良好焊缝,实现单面焊双面一次成形。与常规埋弧焊(SAW)焊接相比,激光焊接变形很小,激光焊缝宽度窄(最宽处5 mm),热影响区小(0.3 mm)。焊缝组织为细小板条马氏体加少量残余奥氏体,硬度HV350,抗拉强度536 N/mm2,经180°冷弯不断裂,具有良好的综合力学强韧性能。

Microstructure and Properties of High Power Laser Welding of Ship Steel Plate

Experiments of high power laser welding of Y gap ship plate have been performed using fast axial flow 10 kW CO2 laser, five-axial computer numerically controlled (CNC) table, St370-2 ship mild-steel plates and SG filling wire. Morphology and microstructure of laser welding seam have been widely examined by optical microscope (OM), scanning electron microscope (SEM) and X-ray diffractometer (XRD). It is shown that no crack full penetration welding in 12 mm thickness ship plate can be achieved at laser power of 8～10 kW and welding speed of 1 m/min. Comparing with submerged-arc welding (SAW), laser welding has a narrow seam width of 5 mm and a small heat-affected zone of 0.3 mm. Microstructure of fine martensite and a small amount residual austenite has been observed in the laser seam, which has a good synthesis mechanical obdurability. Mechanical tests of hardness of HV350, tensile strength of 536 N/mm2 and 180° cold bend without fracture have been measured.