电子束横焊3mm纯铌板的熔池形态研究

Molten Pool State for Horizontal EBW on 3mm Niobium Plate

摘要:

高能加速器纯铌超导腔内导体,要求加工后的外表面光滑平整,以保证其特殊性能的要求。在电子束平焊全熔透情况下,超导腔焊缝正面在反冲压力作用下易发生未焊满及塌陷等缺陷。本文采用合适的电子束横焊工艺参数,得到了符合工艺要求的正面余高焊缝。并且建立了3mm厚的高纯铌板横焊过程的二维模型,针对不同的焊接参数分别设计了不同尺寸和形状的熔池,结合VOF算法,模拟焊接熔池里液态金属自由表面存在状态,得到了不同焊接参数下熔池的演变过程。实验结果显示,焊接熔宽随焊接线能量的升高而增大,数值模拟与实验结果较吻合。

Abstract:

Inner conductor in Niobium superconducting cavity requires a smooth outer surface after material processing, in order to enable the special performance. In the case of downward EBW with full penetration, defects such as underfill and collapse in the face of weld can happen affected by the recoil pressure. In this paper, proper horizontal EBW parameters are used to achieve weld with front reinforcement in accordance with the technical requirements. A 2-D model for the horizontal welding process of 3mm Niobium plate is constructed, and molten pool models with different size and shape are built for different welding parameters. VOF method is applied to simulate the free-surface status of molten pool metal during the welding process, and to obtain the molten pool evolution for different welding parameters. Experiment result indicates the weld width increases with the rise of heat input, and the simulation result matches the experiment.