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本文采用理论和试验相结合的方法系统研究了激光深熔焊接GG17玻璃时的小孔效应。首先采用高速摄影的方法清晰、完整地观测到了激光深熔焊接GG17玻璃时小孔的形状,并通过实验研究了聚焦光斑尺寸、离焦量、焊接速度等焊接工艺参数对小孔尺寸和形状的影响。然后,论文根据实验得到的小孔形状,通过曲线拟合的方法得到小孔前后沿孔壁的曲线方程,再按照几何光学原理,分析了激光在小孔孔壁上的多次反射吸收情况,并由此计算出了小孔孔壁通过多次反射吸收的激光功率密度分布情况。最后,建立了一个分层圆柱体面热源传热模型,在综合考虑热传导和熔池对流换热的基础上,计算了小孔周围的温度场和流场,求出了小孔孔壁上的热流密度分布,并与小孔孔壁吸收的激光功率密度进行了比较。
In this paper, the combination of theory and experiment was used to systematically study the pinhole effect when laser deep-welding GG17 glass. Firstly, the shape of the small holes in the laser welding of GG17 glass was clearly and completely observed by high-speed photography. The effects of the welding parameters such as focal spot size, defocusing amount and welding speed on the size and shape of the holes influences. Then, according to the shapes of the holes obtained by the experiment, the curve equations of the hole walls before and after the holes are obtained by the curve fitting method, and then the multiple reflection absorption of the laser on the hole walls of the small holes is analyzed according to the principle of geometrical optics. The distribution of the laser power density through the multiple reflection absorption is calculated. Finally, a heat transfer model of layered cylindrical surface heat source was established. Based on the heat conduction and the convective heat transfer in the weld pool, the temperature field and flow field around the orifice were calculated, and the heat flux The density distribution is compared with the laser power density absorbed by the pinhole wall.