高压环境下脉冲GMAW焊接参数对焊接过程及飞溅的影响

发布时间：2018-08-03 20:22

【摘要】：伴随着社会与经济的迅速发展,海洋油气资源日益成为竞争的焦点。海洋油气资源的开发离不开海上结构物和海底管道,因此海洋装置的维修变得愈加重要。高压干法水下焊接不但可以获得良好的焊接质量,还可以很好的适应水下高压环境。而在水下高压干法焊接技术中,脉冲GMAW越来越受到重视,因为它具有较多的调节参数和较好的控制能力。受到水下高压环境的影响,高压焊接的焊接过程并不稳定,并且随着水下压力逐渐增加,焊接过程的稳定性逐渐下降。因此研究高压环境下脉冲参数对焊接的影响十分重要。本实验利用高压实验舱模拟水下高压环境,设定实验舱压力值,进行脉冲GMAW焊接试验。通过汉诺威分析仪采集焊接过程图像,对焊接电信号图像进行分析,通过电信号的变化趋势,指导相应参数的调节。利用高速摄像及时观察不同参数的熔滴过渡情况,对比不同参数的熔滴过渡形式。焊后,针对于每一种焊接参数所得的焊缝,观察焊缝成形情况,找出相应的变化规律,总结得出:平均电流主要影响焊丝的熔敷率,增加平均电流可以使焊接过程稳定,焊缝成形变好。电弧电压既可以改变电弧高度也调节电弧挺度。高压环境下电压可以改变焊缝的宽度,并且可以有效的缓解焊接飞溅;峰值时间、频率主要影响焊接电弧能量,不仅可以提高焊丝的熔敷效率还可以有效的改善焊接过程的稳定性,增加频率和峰值时间可以有效的控制短路现象的发生;过渡电流和过渡时间主要影响熔滴过渡情况,二者合理的配比可以有效地控制飞溅的大小,但对焊缝成形外观影响不大;高压环境下采用直流正接可以有效改善焊缝成形,尤其是当压力超过0.4MPa时,采用直流正接焊接方式,焊接飞溅较少,且飞溅颗粒小。本文通过一系列的焊接实验,总结出脉冲焊接参数对不同压力下脉冲GMAW的影响情况,分析了高压环境下焊缝成形的原因。为开发相应的脉冲GMAW焊接设备和获得良好的焊接质量奠定理论基础,为将来进行水下焊接研究提供重要参考。
[Abstract]:With the rapid development of society and economy, offshore oil and gas resources increasingly become the focus of competition. The development of offshore oil and gas resources can not be separated from offshore structures and submarine pipelines, so the maintenance of offshore installations becomes more and more important. High pressure dry underwater welding can not only obtain good welding quality, but also adapt to underwater high pressure environment. In the underwater high pressure dry welding technology, pulse GMAW is paid more and more attention because it has more adjustment parameters and better control ability. Under the influence of underwater high pressure environment, the welding process of high pressure welding is unstable, and with the increase of underwater pressure, the stability of welding process decreases gradually. Therefore, it is very important to study the influence of pulse parameters on welding under high pressure. In this experiment, the high pressure experimental cabin was used to simulate the underwater high pressure environment, the pressure value of the experimental cabin was set, and the pulsed GMAW welding test was carried out. The welding process image was collected by Hannover analyzer, and the welding electrical signal image was analyzed. Through the change trend of the electric signal, the adjustment of the corresponding parameters was guided. The droplet transfer with different parameters was observed and the droplet transfer patterns with different parameters were compared by high speed camera. After welding, according to the welding seam obtained from each kind of welding parameters, observe the weld forming condition, find out the corresponding change rule, conclude: the average current mainly affects the deposition rate of the welding wire, increase the average current can make the welding process stable, The weld formed better. The arc voltage can not only change the arc height but also adjust the arc stiffness. The voltage can change the width of welding seam under high voltage environment, and can effectively alleviate the welding spatter, the peak time and frequency mainly affect the welding arc energy, Not only can the deposition efficiency of welding wire be improved, but also the stability of welding process can be effectively improved, and the occurrence of short circuit can be effectively controlled by increasing frequency and peak time, and the transition current and transition time mainly affect the droplet transfer. The reasonable ratio of the two can effectively control the size of spatter, but it has little effect on the appearance of weld formation, the direct current forward connection can effectively improve the weld formation under high pressure, especially when the pressure exceeds 0.4MPa, the direct current forward welding method is adopted. The welding spatter is less and the spatter particle is small. In this paper, through a series of welding experiments, the influence of pulse welding parameters on pulsed GMAW under different pressure is summarized, and the reasons of weld forming under high pressure are analyzed. It lays a theoretical foundation for developing corresponding pulsed GMAW welding equipment and obtaining good welding quality, and provides an important reference for underwater welding research in the future.
【学位授予单位】：北京石油化工学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG444.72

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