穿孔型等离子弧焊接热-力耦合模型优化

Optimization of thermal mechanical coupled model of KPAW

K-PAW的焊接过程是等离子电弧对被焊工件热与力的耦合作用.文中基于FLUENT软件,依据流体动力学理论,对穿孔型等离子弧焊接过程熔池、流场和小孔进行了热-力耦合模型分析,提出了随穿孔深度增加,能量和电弧压力二次变化的计算优化模型,使维持小孔壁面稳定的力同时作用在小孔内部和物理边界上,初步实现了穿孔型等离子弧焊接从开始到穿透工件及穿孔后焊接过程的数值模拟.计算结果表明,焊接时间为0.25 s时,熔池已开始熔化并出现下凹变形,穿孔型等离子弧焊接穿孔时间为2.15 s,焊接3.00 s后小孔和熔池达到稳定状态,与试验测得的穿孔时间吻合良好,在穿孔动态过程中穿孔形态吻合良好,熔合线走势基本相同.另外,在平行于焊缝的截面上观察,熔池内部易出现逆时针环流.

Based on the theory of fluid dynamics,thermal mechanical coupled model of weld pool,keyhole and flow field of K-PAW( Keyhole Plasma Arc Welding) are studied with FLUENT software in this paper. A optimized model of energy and arc pressure changed quadratically as the depth of keyhole increasing is proposed. Furthermore,the forces maintaining keyhole stable act inside of the keyhole and on the physical boundary at the same time. The numerical simulation of penetration process and welding process after penetration are realized initially with this method. It takes 2. 15 s to penetrate the whole workpiece at the calculated result which is in agreement with the penetrating time of experimental measurement. And the forms of keyhole agree well during dynamic penetrating process. The trend of fusion line is same basically.