电子束非穿透焊接匙孔行为数值模拟及气孔抑制方法

Numerical Simulation of Keyhole Behavior and Porosity Suppression Methods of Electron Beam Partial Penetration Welding

针对航空发动机常用非穿透焊锁底接头电子束深熔焊易出现气孔缺陷的现象,建立了一个可描述电子束焊接过程瞬态匙孔和熔池动力学的三维数学模型,对焊接过程进行了模拟。对比实验和模拟结果发现,电子束非穿透深熔焊接气孔产生的根本原因是匙孔不稳定塌陷形成空穴,空穴被凝固前沿捕获所致。对脉冲电子束焊接过程进行模拟发现,随着电子束脉冲频率增加,匙孔稳定状态增强,当频率达到1000 Hz时,匙孔始终处于动态稳定的平衡状态,此时能有效控制焊缝气孔缺陷。该研究为指导电子束深熔焊接气孔缺陷抑制提供了理论依据。

Porosity defects are often occurred in electron beam welded locked butt joint of aero-engine.A 3D numerical model of the transient keyhole and molten pool dynamics during electron beam welding was established to simulate the welding process.By comparing the experimental results with simulation results,the reason of porosity formation is the cavity from collapse of unstable keyhole captured by the solidified front.The simulation of pulsed electron beam welding proved that,the higher the pulsed frequency,the more stable the keyhole.When the frequency is 1000 Hz,the keyhole was dynamically stable,and porosity defect was effectively suppressed.The results provide a theoretical basis for the suppression of porosity defects in non-penetration electron beam welding.