MIG焊接熔池形成与凝固过程数值模拟  

Numerical analysis of weld pool formation and solidification in MIG welding process

作　　者：吴东升[1] 华学明[1] 叶定剑[1] 张菁[1] 顾煜[1] 李芳[1] 

机构地区：[1]上海交通大学上海市激光制造与材料改性重点试验室,200240

出　　处：《焊接》2015年第9期6-11,73,共6页Welding & Joining

基　　金：国家自然科学基金(51275299)

摘　　要：利用FLOW3D软件建立三维数学模型,模拟A36船用低碳钢熔化极惰性气体保护焊(MIG)的瞬态温度场和流场,分析起弧后熔池形成和熄弧后熔池凝固两个过程。采用了双椭球热源模型,考虑了重力、电弧压力、表面张力、电磁力、浮力,以及辐射、蒸发、熔滴的动态冲击作用。结果表明,熔池形成过程中,熔池前部发生下凹变形,熔深慢慢增大,达到准稳态后基本保持不变。电弧下方液态金属温度最高,最高温度随时间变化不大,熔池内同时存在熔滴冲击力、电磁力引起的向内流动和表面张力引起的向外流动。熄弧后,熔池内只存在表面张力引起的向外流动,震荡幅度降低。熔池横截面具有一个较大的外接触角(均大于π/2),此时尽管存在液态金属的震荡,熔池也是稳定的。模拟预测的焊缝尺寸,形状与试验吻合良好。A three- dimensional model of weld pool convection in MIG process was built to study the weld pool formation and solidification by using the commercial software FL0W3 D.The double ellipsoid heat source model was used,the liquid metal flow and heat transfer driven by gravity,arc pressure,surface tension force,electromagnetic force and buoyancy were considered.The radiation,evaporation and droplet inpact were also taken into account.The results show that,during the formation of the molten pool,the front portion of the pool is depressed,weld penetration,weld width and weld reinforcement develop gradually as weld time increases,and do not change when reaches quasi- steady state.The temperature under the arc is the highest,and there are both inward and outward flow patterns inside the pool.After arc extinction,there is only the outward flow pattern.The weld pool has an external contact angle greater than π/2,thus the pool is stable in spite of changes in cross section due to fluid oscillations.Simulation results are in good agreement with the experimental results.

关 键 词：A36低碳钢 双椭球热源 熔池流动 熄弧 熔池凝固 

分 类 号：TG402[金属学及工艺—焊接]