Modelling of a Grade 91 power plant pressurised header weldment under ultra super-critical creep conditions
Modelling of a Grade 91 power plant pressurised header weldment under ultra super-critical creep conditions
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DOI：
10.1016/j.ijpvp.2021.104389
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发表时间：
2021-04-02
影响因子：
3
通讯作者：
Sun, W.
中科院分区：
文献类型：
--
作者：
Ragab, R.;Parker, J.;Sun, W.
本文研究了91级承压集箱的蠕变损伤模型。将Kachanov型多轴蠕变损伤模型应用于有限元分析中，研究了焊接接头及其母材、焊缝和热影响区的蠕变损伤响应。每个焊接成分的材料特性是从顶盖中提取的材料的加速蠕变试验结果中获得的。对短柱至集管焊缝的截面进行裂纹萌生预测。该分析也被用于估计超超临界条件下的集箱焊接件的蠕变失效寿命。此外，蠕变裂纹扩展行为的预测依赖于时间的临界损伤增长的基础上。预测的跨焊缝蠕变试样的损伤分布和失效模式与报告的实验观察结果吻合良好。预测的损伤分布和裂纹的头部相关合理，以及报告的工业观察。
This paper is concerned with the creep-damage modelling of a Grade 91 pressurised header, which was observed to undergo in-service cracking in the weldments. A multi-axial creep damage model of Kachanov type, with a single state damage variable, has been implemented into finite element analysis to study the creep damage responses of weldments and the sub-zones i.e. the base metal (BM), weld metal (WM) and heat-affected zone (HAZ). Material properties for each weld constituent were obtained from the results of accelerated creep tests on materials extracted from the header. Predictions of crack initiation were made for sections of the stub to header welds. This analysis was also used to estimate creep failure life of the header weldment under ultra-super-critical conditions. Further, creep crack growth behaviour was predicted based on time-dependent critical damage growth. The predicted damage distributions and failure mode of the cross-weld creep test specimens were in good agreement with the reported experimental observations. The predicted damage distributions and cracking in the header correlate reasonably well with the reported industrial observations.