送丝速度对电弧增材熔池流动及焊道成形影响的数值模拟

Numerical simulation of the effect of wire feeding speed on the molten pool flow and weld bead morphology of WAAM

通过数值模拟研究了不同送丝速度下电弧增材制造单道熔积成形过程中的传热传质及熔池流态,分析了送丝速度对焊道形貌的影响.结果表明,当送丝速度较小时,基板接受的电弧热较多,熔池的熔深较深且流动性较强,成形焊道较宽且高度较低;随着送丝速度的增大,熔融金属向上堆积,熔池体积增加,送丝速度达到一定值时,电磁力与表面张力达到动态平衡,熔深与焊道高度接近;当送丝速度较大时,液态金属对流减弱,熔深较浅,在表面张力的作用下,熔池边缘收缩导致焊道隆起.模拟与试验结果吻合较好,研究结果可以为GTAW电弧增材技术的工艺参数调控提供理论依据.创新点:通过数值模拟方法探究了送丝速度影响电弧增材制造熔池传热与流动,以及焊道成形的作用机理.

The heat and mass transfer and molten pool flow in single-pass deposition of wire arc additive manufacturing(WAAM)were studied using numerical simulation,and the influence of wire feeding speed on weld bead morphology was analyzed.The results show that when the wire feeding speed is low,the substrate receives more arc heat,the molten pool has deeper penetration and stronger fluidity,and the weld bead width is wide with a low height.As the wire feeding speed increases,the molten metal accumulates upward,and the molten pool volume increases.When the wire feeding speed reaches a certain value,the electromagnetic force and surface tension achieve a dynamic balance,and the molten pool penetration approaches the weld bead height.At higher wire feed speeds,molten pool convection tends to weaken,and penetration becomes shallow.Under the action of surface tension,edge shrinkage of the weld pool leads to weld bead bumps.The simulated single-bead cross-sectional profile agrees well with experimental results and can provide theoretical bases for controlling process parameters in gas tungsten arc welding-based additive manufacturing technology.Highlights:The effect mechanism of wire feed speed on heat transfer and molten pool flow in single-pass deposition of wire arc additive manufacturing is studied by numerical simulation.