药芯焊丝摇动电弧窄间隙焊接熔滴过渡及焊缝成形研究

发布时间：2018-11-03 17:41

【摘要】：本文针对摇动电弧窄间隙MAG焊方法,构建了一种采用背景光源的焊接电弧高速摄像采集系统,观测了实芯焊丝和药芯焊丝在窄间隙焊接中的熔滴过渡特性,分析了焊接飞溅形式和焊接电弧稳定性,并研究了平位置焊接摇动工艺参数(摇动频率、摇动角度和侧壁停留时间)对焊缝成形的影响,以及立向上焊接时的摇动工艺参数、送丝速度和线能量一定条件下同时改变送丝速度和焊接速度对焊缝成形的影响。在平位置及立向上位置焊接时,熔滴过渡频率变化特征和过渡形式不同。药芯焊丝焊接过程中,当摇动频率较大时,焊丝在坡口中心位置时的熔滴过渡频率大于侧壁停留时的稳定电弧熔滴过渡频率;摇动频率较小时,焊丝在坡口中心位置时的熔滴过渡频率小于侧壁停留时的稳定电弧熔滴过渡频率。而实芯焊丝焊接时熔滴过渡频率规律与较小的摇动频率条件下药芯焊丝熔滴过渡频率规律相同。药芯焊丝和实芯焊丝平位置焊接时,摇动频率为1.5Hz和2.5Hz的电弧更稳定,焊接过程中飞溅的形式主要为射流过渡飞溅和细颗粒飞溅,并有少量爆炸飞溅;立向上焊接时,摇动频率为0.6Hz和0.8Hz时电弧较稳定,焊接飞溅的形式主要为射流过渡飞溅和滴状飞溅,并含有少量爆炸飞溅和短路飞溅。平位置焊接时,药芯焊丝焊渣横截面积随摇动频率增大而减小,随侧壁停留时间和工艺预留间隙的增加而有所增加,焊渣表面弯曲度与焊渣截面积的变化趋势相反;坡口侧壁熔深随摇动频率和侧壁停留时间的增大而增加,而底部熔深与侧壁熔深变化趋势相反;工艺预留间隙的减小均可增加底部和侧壁熔深。立向上位置焊接时,送丝速度的增加,导致焊缝侧壁熔深及底部熔深增加,而焊缝表面弯曲度及焊渣表面弯曲度减小;焊接线能量一定的前提下,送丝速度和焊接速度的增加有利于增加焊缝侧壁熔深和底部熔深。
[Abstract]:In this paper, aiming at the method of rocking arc narrow gap MAG welding, a high speed video acquisition system of welding arc using background light source is constructed, and the droplet transfer characteristics of solid cored wire and flux cored wire in narrow gap welding are observed. The form of welding spatter and the stability of welding arc are analyzed, and the influence of flat-position welding rocking process parameters (rocking frequency, rocking angle and lateral wall residence time) on weld formation and the rocking process parameters in vertical welding are studied. The effect of wire feeding speed and welding speed on weld formation was studied under the condition of wire feeding speed and wire energy. When welding in horizontal position and vertical position, the change characteristics and transition forms of droplet transfer frequency are different. In the process of flux-cored wire welding, the droplet transfer frequency of flux cored wire at the center of the groove is higher than that of the stable arc droplet transfer when the side wall stays. When the rocking frequency is small, the droplet transfer frequency of welding wire at the center of the groove is smaller than that of the stable arc droplet transfer when the side wall stays. However, the flux-cored wire transfer frequency is the same as that of flux-cored wire under the condition of small rocking frequency. The arc with rocking frequency of 1.5Hz and 2.5Hz is more stable when flux-cored wire and solid cored wire are welded in flat position. The main forms of spatter in welding process are jet transfer spatter and fine particle splashing, and there are a few explosive spatter. When the vertical welding frequency is 0.6Hz and 0.8Hz, the arc is stable. The welding spatter is mainly in the form of jet transfer splashing and droplet spatter, and contains a small amount of explosive splashing and short-circuit splashing. The cross section area of flux-cored wire welding slag decreases with the increase of rocking frequency and increases with the increase of side wall residence time and process reserved gap. The change trend of surface bending of flux cored wire welding slag is opposite to that of welding slag cross section area. The depth of the sloping side wall increases with the increase of the rocking frequency and the residence time of the side wall, but the change trend of the bottom penetration is opposite to that of the side wall, and the decrease of the process reserve gap can increase the bottom and side wall penetration. When welding in vertical position, the wire feeding speed increases, which leads to the increase of the penetration depth of the side wall and the bottom of the weld, and the decrease of the bending degree of the weld surface and the surface curvature of the slag. The increase of wire feeding speed and welding speed is beneficial to increase the penetration depth of the side wall and the bottom of the weld under the condition of constant welding line energy.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG44

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