Abstract

The creep rupture life of ferritic heat-resistant steel weld joints is limited by Type IV cracking that occurs in the heat-affected zone (HAZ), whose shape affects creep damage accumulation. In this study, we address the inverse problem of extending the creep rupture life of weld joints by controlling HAZ shape via welding conditions. As reported separately, we have developed a workflow that predicts weld joint creep rupture life from the predicted HAZ shape from welding conditions and have implemented it in the material design system. Using this workflow, we presented a tandem Bayesian model for predicting the creep rupture life from welding conditions via the geometric features of HAZ shapes (HAZ shape factors), which are considered to determine the creep rupture life. The prediction model of a HAZ shape factor from welding conditions was formed by Gaussian process regression. The prediction model of the creep rupture life was formed by Bayesian linear regression. These models were probabilistically connected by Bayesian statistical mathematics. An algorithm to increase the creep rupture life was developed to search for welding conditions. This method was applied to a 2 1/4Cr–1Mo heat-resistant steel weld joint simulated with a plate I-bevel three-layer gas tungsten arc welding. The number of welding conditions combination reaches \({7}^{8}=5764801\) . Start from 49 initial HAZ shape factors and 22 creep rupture life data, we performed forward calculations of 20 rupture lives to find welding conditions that can improve the creep rupture life by 12% over the initial data.

中文翻译：

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考虑 2 1/4Cr–1Mo 钢的 HAZ 形状因素，寻找高蠕变强度焊接条件

摘要

铁素体耐热钢焊接接头的蠕变断裂寿命受到热影响区（HAZ）中发生的IV型裂纹的限制，其形状影响蠕变损伤累积。在这项研究中，我们通过焊接条件控制热影响区形状来解决延长焊接接头蠕变断裂寿命的逆问题。正如单独报道的，我们开发了一种工作流程，可以根据焊接条件预测的热影响区形状来预测焊接接头蠕变断裂寿命，并将其应用到材料设计系统中。使用此工作流程，我们提出了一个串联贝叶斯模型，用于通过 HAZ 形状的几何特征（HAZ 形状因子）根据焊接条件预测蠕变断裂寿命，这些特征被认为是确定蠕变断裂寿命的因素。通过高斯过程回归建立了焊接条件下HAZ形状因子的预测模型。采用贝叶斯线性回归建立蠕变断裂寿命预测模型。这些模型通过贝叶斯统计数学进行概率连接。开发了一种增加蠕变断裂寿命的算法来寻找焊接条件。该方法应用于2 1/4Cr-1Mo耐热钢焊接接头模拟板工字坡口三层钨极气体保护焊。焊接条件组合数量达到\({7}^{8}=5764801\)。从 49 个初始 HAZ 形状因子和 22 个蠕变断裂寿命数据开始，我们对 20 个断裂寿命进行了正向计算，以找到可以将蠕变断裂寿命比初始数据提高 12% 的焊接条件。