活性激光焊接等离子体及熔池形态分析

发布时间：2018-04-21 04:30

本文选题：活性剂 + 活性激光焊接　；参考：《哈尔滨理工大学》2017年硕士论文

【摘要】：活性激光焊接技术与传统激光焊接技术相比,能有效的增加焊缝熔深,减少焊缝熔宽。活性激光焊接技术在保证传统激光焊接技术优点的前提下,降低焊接所需要的功率和热输入,能有效的降低成本,提高生产效率,提高焊接质量。因此活性激光焊接技术研究与应用受到国内外热切关注。为了研究活性剂对激光焊的作用机理,本文从电弧形态的角度进行深入分析。由于激光电弧很难被直接观测到,因此从活性剂对等离子体的影响以及活性剂对熔池形态的影响两个方向进行研究。本文首先以304不锈钢为研究材料,采用高功率半导体激光焊进行平板堆焊,运用高速摄影技术,采集和分析活性剂对激光焊接电弧形态的影响规律。其次以H13热作模具钢为研究材料,采用低功率脉冲激光焊进行平板堆焊,运用CCD监控系统,采集熔池形态和分析活性剂对激光焊接熔池的影响规律。最后整理和分析上述实验结果,对活性激光焊接机理进行分析研究。针对高功率半导体激光焊,运用高速摄影技术采集等离子体形态,通过图像灰度处理、图像滤波去噪、图像二值化、图像边缘提取以及提取特征值等过程对采集到的图片信息进行提取。实验结果表明,活性剂能有效抑制等离子体的产生,Si O2和混合活性剂分别降低等离子体高度的30.7%和46.1%,Cr2O3、Si O2和混合活性剂分别降低等离子体截面积的37.3%、41.4%和44.3%,有效的抑制光致等离子体对入射激光的屏蔽作用。针对低功率脉冲激光焊,运用CCD监控系统观测活性剂对脉冲激光焊熔池形态的影响,并观测焊缝形态的变化规律。实验结果表明,活性剂能改变焊缝熔池形状,增加焊缝熔融金属量,增加焊缝熔深,活性激光焊熔深最高可达到传统激光焊的1.67倍。同时活性剂对焊缝韧性有一定的提高作用。不同的激光焊接参数对活性剂的作用效果产生一定的影响,随着离焦量的增加,活性剂的作用效果降低。通过对活性激光焊接电弧形态的研究结果表明,活性剂能降低等离子对激光电弧能量的吸收效果,改变熔池熔融金属液的流动方向,增加焊接材料对激光能量的吸收效率,起到增加焊缝熔深,减少焊缝熔宽的效果。
[Abstract]:Compared with traditional laser welding technology, active laser welding technology can effectively increase weld penetration and reduce weld width. The active laser welding technology can effectively reduce the cost, improve the production efficiency and improve the welding quality by reducing the power and heat input required by the traditional laser welding technology on the premise of guaranteeing the advantages of the traditional laser welding technology. Therefore, the research and application of active laser welding technology have attracted much attention at home and abroad. In order to study the action mechanism of active agent on laser welding, the arc shape is analyzed in this paper. Because the laser arc is difficult to be observed directly, the influence of active agent on plasma and the influence of active agent on the morphology of molten pool are studied. In this paper, firstly, 304 stainless steel is used as the research material, high power semiconductor laser welding is used for flat surfacing welding. High speed photography is used to collect and analyze the influence of active agents on the shape of laser welding arc. Secondly, the H13 hot working die steel is used as the research material, the low power pulsed laser welding is used for flat surfacing welding, and the CCD monitoring system is used to collect the weld pool shape and analyze the influence of the active agent on the laser welding weld pool. Finally, the experimental results are analyzed and the mechanism of active laser welding is studied. For high power semiconductor laser welding, high speed photography is used to collect plasma morphology, image grayscale processing, image filtering and denoising, image binarization, Image edge extraction and feature extraction are used to extract the image information. The experimental results show that, The active agent can effectively inhibit the generation of plasma by 30.7% and 46.1% of the plasma height, respectively, and the mixed active agent can reduce the plasma cross-sectional area by 37.3% and 44.3%, respectively, and effectively suppress the photoinduced plasma by 37.3% and 44.3% of the plasma cross-sectional area, respectively, and the mixture of active agents can reduce the plasma height by 30.7% and 46.1%, respectively. Shielding effect on incident laser. Aiming at low power pulsed laser welding, the influence of active agent on weld pool morphology of pulsed laser welding was observed by CCD monitoring system, and the variation rule of weld shape was observed. The experimental results show that the active laser welding can change the weld pool shape, increase the amount of weld metal and increase the weld penetration. The maximum penetration of active laser welding is 1.67 times that of conventional laser welding. At the same time, the active agent can improve the toughness of weld seam to a certain extent. Different laser welding parameters have a certain effect on the effect of the active agent. With the increase of the defocusing amount, the effect of the active agent decreases. The results show that the active laser welding arc morphology can reduce the absorption of laser arc energy by plasma, change the flow direction of molten metal in the molten pool, and increase the absorption efficiency of laser energy of welding materials. It can increase weld penetration and reduce weld width.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG456.7

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