Abstract Nickel-based alloys play an important role in the field of high-temperature alloys, which are widely used in nuclear reactors, aerospace and components of turbomachinery. However, the high susceptibility of welding hot crack is a main shortcoming to nickel-based alloys. One of the methods that reduce hot cracking susceptibility is by adjusting element constitution of weld metal and another method is by reducing transient stress. This article used finite element method to study the effect of cooling source on transient stress of the nickel-based alloy weld joint. The selection of appropriate cooling technique can decrease the peak of the transient von Mises stress and make the tensile stress turn into compressive stress, which is beneficial to reduce hot cracking susceptibility. The peak of the transient von Mises stress decreases as the cooling intensity increases from 0 to 15,000 W/m2 K, but increases if the cooling intensity is ineffective. When the distance between cooling source and heat source reaches 35 mm, the weld can get larger region of compressive stress. The peak of the transient von Mises stress decreases with increasing radius of cooling source and reaches minimum value at 12 mm. Combined cooling is more effective in reducing the peak of this stress than the conventional single trailing cooling source.

中文翻译：

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不同冷却技术下镍基合金焊接瞬态应力的数值模拟

摘要 镍基合金在高温合金领域占有重要地位，广泛应用于核反应堆、航空航天和涡轮机械部件。然而，焊接热裂纹的高敏感性是镍基合金的主要缺点。降低热裂纹敏感性的方法之一是调整焊缝金属的元素组成，另一种方法是降低瞬态应力。本文采用有限元方法研究了冷源对镍基合金焊接接头瞬态应力的影响。选择合适的冷却技术可以降低瞬态von Mises应力峰值，使拉应力转变为压应力，有利于降低热裂敏感性。当冷却强度从 0 增加到 15,000 W/m2 K 时，瞬态 von Mises 应力的峰值会降低，但如果冷却强度无效，则会增加。当冷源与热源的距离达到35mm时，焊缝可获得较大的压应力区域。瞬态 von Mises 应力的峰值随着冷却源半径的增加而减小，并在 12 mm 处达到最小值。与传统的单个尾随冷却源相比，组合冷却在降低该应力峰值方面更有效。瞬态 von Mises 应力的峰值随着冷却源半径的增加而减小，并在 12 mm 处达到最小值。与传统的单个尾随冷却源相比，组合冷却在降低该应力峰值方面更有效。瞬态 von Mises 应力的峰值随着冷却源半径的增加而减小，并在 12 mm 处达到最小值。与传统的单个尾随冷却源相比，组合冷却在降低该应力峰值方面更有效。