Abstract

The creep rupture life of weld joints decreases to values from half to one-tenth of that of the base metal in Cr–Mo heat-resistant steels. It is industrially very important to understand the creep performance of weld joints and to minimize the reduction in the creep performance of weld joints relative to the base metal. In this study, a consistent prediction computational workflow was developed for practical three-layer cladding welds that connect two modules. These are the weld heat transfer analysis module, which predicts the heat-affected zone (HAZ) shape from welding conditions, and the creep damage analysis module, which calculates the creep rupture life from the predicted shape of the HAZ. Using this workflow, we examined the effects of welding conditions on creep rupture life of 2.25Cr-1Mo steel. Welding conditions were selected on the basis of the design of experiment method, and the correlation between each factor and creep rupture life was evaluated by factorial effect analysis. The results clarify that the creep rupture life changed significantly depending on the control of welding heat input under conditions that simulate practical welding. This suggests that there is an appropriate welding heat input to bring the creep rupture life of weld joints close to that of the base metal. Although previous studies of creep rupture life with relatively simple HAZ geometries have indicated the correlation with the width and angle of HAZ, it was newly discovered that these indices cannot simply explain the creep rupture life of the weld joints with complex HAZ geometries that appear in practical welding. The effect of HAZ shape on creep rupture life is more complicated than previously reported, suggesting that more appropriate HAZ shape factors should be considered.

中文翻译：

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从焊接条件预测2.25Cr-1Mo钢蠕变寿命的分析方法研究

摘要

Cr-Mo耐热钢焊接接头的蠕变断裂寿命降低至母材的一半至十分之一。了解焊接接头的蠕变性能并尽量减少焊接接头相对于母材蠕变性能的降低在工业上非常重要。在本研究中，为连接两个模块的实际三层堆焊焊缝开发了一致的预测计算工作流程。它们是焊接传热分析模块和蠕变损伤分析模块，前者根据焊接条件预测热影响区 (HAZ) 形状，后者根据预测的 HAZ 形状计算蠕变断裂寿命。使用此工作流程，我们检查了焊接条件对 2.25Cr-1Mo 钢蠕变断裂寿命的影响。根据实验方法设计选择焊接条件，并通过因子效应分析评价各因素与蠕变断裂寿命的相关性。结果表明，在模拟实际焊接的条件下，蠕变断裂寿命会根据焊接热输入的控制而发生显着变化。这表明存在适当的焊接热输入以使焊缝的蠕变断裂寿命接近母材的蠕变断裂寿命。虽然之前对相对简单的热影响区蠕变断裂寿命的研究表明了与热影响区宽度和角度的相关性，但新发现这些指标并不能简单地解释实际中出现的复杂热影响区焊缝的蠕变断裂寿命。焊接。HAZ形状对蠕变断裂寿命的影响比之前报道的更为复杂，这表明应考虑更合适的HAZ形状因素。