Crack growth behaviour of P92 steel under creep and creep–fatigue conditions

Abstract

High temperature creep and creep–fatigue crack growth tests were carried out on standard compact specimens machined from ASME P92 steel pipe. The effects of various loading conditions on crack growth behaviours were investigated. Crack initiation time was found to decrease with the increasing initial stress intensity factor under creep condition and further to decrease by the introduction of fatigue condition. For creep test, the crack growth rate can be well characterised by the facture mechanics parameter C*. For creep–fatigue test, the crack growth behaviour is dominated by the cycle dependent fatigue process when the hold time is shorter, but it becomes dominated by the time dependent creep process when the hold time becomes longer.     

Effect of temperature on fatigue crack growth in P92 steel

Fracture at high temperature has become a critical problem for such high temperature components as those used in power plants or oil refinery plants, because both high operating temperature and pressure are required for better thermal efficiency. Therefore, it is very important to approach such problems from the viewpoint of high temperature material properties. Since fatigue and creep are closely related to such components failures, the fracture behavior in high temperature components must be evaluated through fatigue and creep crack growth tests, and based on these results, better operating conditions can be determined. In this study, recently developed P92 (9Cr-2W) alloy steel, which is a high strength material for high temperature use, is investigated and its fatigue crack growth has been characterized by Paris law. A series of high temperature fatigue tests were carried out at 400, 500, 550, 600, 625, 650, and 700°C to verify the temperature effect. The results indicated that the Paris exponent remained at approximately the same value up to a certain temperature. From 600 to 700°C, creep rupture tests were conducted in order to investigate the creep behavior with temperature. Further analysis has also been carried out to investigate the effect of temperature on fracture mode shift, dimple formation, and its role in crack growth rate and deformability at high temperature.     

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CDF分析方法及其计算程序研究

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Continuous and impulsive harvesting strategies in a stage-structured predator–prey model with time delay

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基于里氏硬度测量的P92钢及焊缝布氏硬度的计算

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P92钢630 ℃下的高温低周疲劳行为分析

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1000MW 超超临界压力发电机组管道用P92钢焊接缺欠及质量控制

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