CO2焊接短路过渡过程的动态分析─短路液桥的动态变化与力学测算

CO₂气体保护焊接是一种高效、节能和低成本的焊接方法,在钢结构焊接生产中得到了广泛的应用。但也存在着诸如:金属飞溅、焊缝成形较差等问题,要解决这些问题,必须首先对CO₂焊接过程的电弧形态以及熔滴变化情况从理论上深入分析研究。本文以高速摄影与光线示波器同步进行拍摄,记录了CO₂悍接短路过渡中熔滴的长大、缩颈、脱落的全过程以及相对应的电流电压波形。利用影片数据分析处理系统对所得影片及记录波形进行了分析处理,得到了熔滴过渡形成金属液桥爆断瞬间的最大电流值及所受合力的大小。从理论上更进一步研究了短路过渡的机理,建立了短路过渡的模型,这对正确调节焊接工艺规范,保证焊接质量具有重大的指导意义,研究结果表明:在常规短路过渡CO₂焊接中,抑制飞溅是提高CO₂焊接质量的关键,利用焊接规范来调节短路频率和短路峰值电流是抑制飞溅的主要途径。

DYNAMIC ANALYSES OF SHORT CIRCUITING TRANSFER PROCESS IN CO2 ARC WELDING-DYNAMIC BEHAVIOUN OF SHORT CIRCUITING LIQUID BRIDGE AND ITS MECHANICAL MEASUREMENT

CO₂ arc welding is a kind of welding technology with high efficiency,economicenergy and low cost,It has been widely used in welding steel structures,but there existpro blems such as metal spatter,bad appearance of weld,etc.In order to resolve theseproblems,it is necessary to approach theoretically the arc characteretlcs and the behaviourof the droplets. In this paper,the all process of droplet growing,necking,dripping andcurrent-voltage waves responding to it during the shorting circuiting transfer in CO₂ arcwelding was recorded synchron ously by high-speed photography and oscillogmphy, whichwere analysed by means of film data processing system to obtain the maximum currentaed the resultant force at the instant when the formed liquid metal bridge exploded duringthe droplet transfer.The mechanism of short circuiting transfer was further investigatedaed a model was establlshed It has important instructive meaning for adjusting the weldingparameters and ensuring the welding quality.It is concluded that in the normal CO₂ arcwelding with short circuiting transfer the spatter controll is key to irnprove welding quality,aed the substantial means by which the spatter is in hibited is adjusting the short circuitingfrequency and the peak current through the change of welding conditions.