铝合金与镀锌钢板CMT焊接过程传热传质现象的数值模拟  

Numerical simulation of heat and mass transfer during CMT welding of aluminum alloy and galvanized mild steel

作　　者：饶政华[1] 李芸霄 刘江维[1] 廖胜明[1] 王凤江[2] 

机构地区：[1]中南大学能源科学与工程学院,湖南长沙410083 [2]江苏科技大学先进焊接技术省级重点实验室,江苏镇江212003

出　　处：《中南大学学报（自然科学版）》2015年第11期4325-4333,共9页Journal of Central South University:Science and Technology

基　　金：中央高校基本科研业务费专项资金资助项目(2013ZZTS206);江苏科技大学先进焊接技术省级重点实验室开放研究基金资助项目(JSAWT-13-03)~~

摘　　要：建立冷金属过渡(CMT)焊接的三维非稳态数学模型,研究铝合金和镀锌钢板CMT焊接过程的传热、传质现象,包括电弧等离子体的形成和变化、焊丝的送入与回抽、熔滴生长与过渡、熔池动态行为、镀锌层的蒸发及锌蒸气在电弧中的扩散。研究结果表明:在高温电弧的作用下钢板表面的镀锌层蒸发,锌蒸气由钢板表面向电弧区扩散,其分布受等离子体流动的影响。焊接过程中焊接电流、电弧长度不断变化,造成焊接工件表面附近的电弧压力持续变化。锌层蒸发增大了钢板表面附近的电弧压力,易造成熔滴过渡和焊接过程的不稳定。A 3D transient cold metal transfer （CMT） welding model was developed to study the heat and mass transfer during CMT welding of aluminum alloy and galvanized steel sheets, which includes arc generation and evolution, up-and-down movement of welding wire, droplet formation and dipping into the weld pool, weld pool dynamics, zinc evaporation and zinc vapor diffusion in the arc. The results show that the zinc layer at the steel surface evaporates and diffuses into the arc under the impact of high-temperature arc, and the zinc vapor distribution is affected by the plasma flow. During the welding process, the welding current and arc length keep changing, leading to the continuous variation of arc pressure at the workpiece surface. The zinc evaporation increases the arc pressure near the steel surface, which always results in the instable metal transfer and welding process.

关 键 词：冷金属过渡 电弧等离子体 传热传质 数值模拟 

分 类 号：TG44[金属学及工艺—焊接]