正负极性CMT铝焊丝熔滴体积增长量分析  

Analysis of Droplet Volume Increasing Amount of Positive and Negative Electrode on Cold Metal Transfer Welding of Aluminum Wire

作　　者：吕小青[1,2] 王壮壮 LüXiaoqing;Wang Zhuangzhuang(School of Materials Science and Engineering,Tianjin University,Tianjin 300350,China;Tianjin Key Laboratory of Advanced Joining Technology,Tianjin 300350,China)

机构地区：[1]天津大学材料科学与工程学院,天津300350 [2]天津市现代连接技术重点实验室,天津300350

出　　处：《天津大学学报（自然科学与工程技术版）》2023年第4期430-435,共6页Journal of Tianjin University：Science and Technology

基　　金：国家自然科学基金资助项目(52075372).

摘　　要：为了定量研究铝焊丝在正负极性冷金属过渡时熔滴体积的变化情况,搭建了VP CMT熔滴过渡图像及电信号采集平台.利用数字图像处理技术,对拍摄得到的熔滴过渡图像进行处理,得到了仅包含焊丝、熔滴轮廓的二值图像.结合焊丝直径与熔滴径向尺寸之间的关系特征,将熔滴与焊丝之间“固-液”分界面的判定分为焊丝直径大于、等于、小于熔滴径向尺寸3种情况进行讨论,提出了判别熔滴与焊丝之间“固-液”分界面的具体方法.首先基于此方法得到了不同工艺参数下,铝焊丝在燃弧阶段不同时刻的瞬时熔滴体积.依据燃弧阶段末期与燃弧阶段初期的熔滴体积,计算得到了不同极性下的熔滴体积增长量.发现在相同的工艺参数下,焊丝极性接负(EN)阶段的熔滴体积增长量明显大于焊丝极性接正(EP)阶段.之后给出了燃弧阶段输入功与熔滴体积增长量之比(W/ΔV)参量,并定量对比了在不同的工艺参数下,EP和EN阶段的W/ΔV变化.结果表明,熔化相同体积的铝焊丝,EP阶段所需要的燃弧阶段输入功约为EN阶段的2.2倍.最后结合焊丝作为阴(阳)极时的产热以及电弧在EN阶段沿焊丝产生“上爬”现象对上述结果进行了解释.该研究为后续精确控制溶滴尺寸,进而控制焊缝成形提供了借鉴.A platform for collecting images and electrical signals of the VP CMT droplet transfer process was devel-oped.This platform allows the researcher to quantitatively investigate the droplet volume variation trend of cold metal transfer of aluminum wire in different polarities.The images of droplet transfer were processed using digital image processing technology,and binary images containing the wire and droplet edge were obtained.The determination of the“solid-liquid”boundary between wire and droplet was divided into three cases based on the relationship be-tween the wire diameter and the droplet radial width:when the wire diameter was greater than,equal to,and smaller than the droplet radial width;and a method was proposed for determining the“solid-liquid”boundary.Ini-tially,the instantaneous droplet volume of different polarities in the plasma phase was calculated under various weld-ing parameters.According to the droplet volume at the end of the plasma phase and the beginning of the plasma phase,increasing droplet volumes of different polarities were obtained.Under the same welding conditions,the in-creasing droplet volume in the electrode negative(EN)phase is greater than that in the electrode positive(EP)phase.Then,the physical parameters of the ratio of input work to the increasing droplet volume in the plasma phase W/ΔV were given.A quantitative comparison was made between the variations of/ΔWV in EP and EN phases under differ-ent welding parameters.The results show that when the same volume of aluminum alloy wire is melted,the EP phase requires about 2.2 times more energy than the EN phase.Finally,the corresponding explanations for the above results were given,combined with the cathode(anode)heat generation and the arc“climb up”phenomenon in the EN phase.This study should provide references for the droplet size control and the weld formation.

关 键 词：变极性冷金属过渡 熔滴体积 图像处理 输入功 

分 类 号：TG403[金属学及工艺—焊接]