Ti2AlNb电子束焊接预热缓冷工艺数值模拟分析

Numerical simulation analysis of preheating and controlled cooling process in electron beam welding of Ti2AlNb alloy

  • 摘要:
    目的 旨在探究焊前预热和焊后热补偿工艺对Ti2AlNb电子束焊接头温度场和残余应力分布的影响。
    方法 采用高斯面热源作为电子束扫描加热热源,高斯面热源模型和三维高斯锥体热源模型组成复合热源模型作为电子束焊接热源,利用有限元分析的方法对Ti2AlNb电子束焊接头进行模拟。
    结果 研究结果表明,焊后热补偿工艺配合焊前预热工艺能够很好地降低接头的温度梯度,从而降低接头冷却速率;同时,焊后热补偿工艺能够显著减少接头表面的高残余应力区域,并能大幅降低焊缝中心中部区域残余应力峰值,但是由于焊后扫描所作用的区域主要集中在焊缝的上半部分,焊后热补偿工艺对接头下部区域的残余应力的影响较小。
    结论 焊后热补偿工艺配合焊前预热工艺能够降低接头的温度梯度,降低焊缝残余应力。

     

    Abstract: Objective This study investigates the influence of pre-weld preheating and post-weld thermal compensation techniques on temperature field and residual stress distribution in Ti2AlNb electron beam welded joints. Methods A Gaussian surface heat source was employed to simulate electron beam scanning heat input. A composite heat source model, comprising a Gaussian surface heat source and a three-dimensional Gaussian conical heat source, was adopted to represent welding heat source. Finite element analysis was conducted to simulate welding process of Ti2AlNb electron beam welded joints. Results The results demonstrate that combining post-weld thermal compensation with pre-weld preheating effectively reduces temperature gradient across the joints, thereby lowering cooling rate. Moreover, the post-weld thermal compensation significantly mitigates high residual stress concentrations on the surface of the joints and substantially decreases peak residual stress in the central region of the weld. However, since the post-weld scanning primarily affects the upper portion of the weld, its influence on residual stress in the lower region of the joints is relatively limited. Conclusion The integrated application of pre-weld preheating and post-weld thermal compensation proves to be an effective strategy for reducing both temperature gradients and residual stresses in Ti2AlNb electron beam welded joints.

     

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