ASTM Round-Robin on Creep-Fatigue and Creep Behavior of P91 Steel

Author(s):  
V. Kalyanasundaram ◽  
A. Saxena ◽  
S. Narasimhachary ◽  
B. Dogan
2011 ◽  
Vol 8 (4) ◽  
pp. 103712 ◽  
Author(s):  
V. Kalyanasundaram ◽  
A. Saxena ◽  
S. Narasimhachary ◽  
B. Dogan ◽  
A. Saxena ◽  
...  

2012 ◽  
Vol 616-618 ◽  
pp. 1787-1796 ◽  
Author(s):  
Dong Mei Ji

Creep-fatigue tests were carried out to study creep-fatigue property of P91 steel in many references. There are two kinds of loading control methods. One is controlled by stress, and the other is controlled by strain. In this study the creep-fatigue test data loading controlled by stress are summarized. Based on these data Supported Vector Machine(SVM) method is used to build up the models to predict the creep-fatigue lifetime of P91 steel. The results show SVM method can be used to predict the creep-fatigue life of P91 steel, and the value of insensitive factor is very important. When the value of insensitive factor is small and the training error of the model is small too, but the prediction ability decreases. On the contrary when insensitive factor is increased, the training error will become large, and the prediction ability will increase. So during the training, mean square error should not be regarded as the unique goal function.


2017 ◽  
Vol 35 (6) ◽  
pp. 529-534
Author(s):  
S. J. Brett ◽  
C. N. C. Dyson ◽  
D. Purdy ◽  
J. Shingledecker ◽  
J. Rantala ◽  
...  

Author(s):  
Akhil Khajuria ◽  
Modassir Akhtar ◽  
Raman Bedi

This paper induced a novel methodology for the characterization of creep behavior of weld heat-affected zone (HAZ) for boron-free P91 (PM) and boron modified P91B (B-PM) steels. Gleeble-3800 thermo-mechanical simulator replicated specimens, representing coarse-grain HAZ (CGHAZ), fine-grained HAZ (FGHAZ), and inter-critical HAZ (ICHAZ). Short-term impression creep tests were conducted at 625°C/270-410MPa on PM/B-PM and their simulated HAZs after being subjected to post-weld heat treatment (PWHT) of 760°C/3 h. Microstructural characterization and local strain analyses were accomplished by electron back-scattered diffraction. Simulated microstructures of P91B-FG/ICHAZ after PWHT exhibited lath martensitic structure and large prior-austenite grain size as regards P91-FG/ICHAZ, correspondingly. Average values of local microstructural strain from local average misorientation were relatively high in B-PM and P91B-ICHAZ than PM and P91-ICHAZ, respectively. Similar observations were found for P91-CG/FGHAZ with their counterparts. Stress dependent steady-state creep-rate (SSCR) followed power-law for all specimens except PM. The minimum and maximum ranges of SSCR for P91B specimens were observed to be in a narrower range than P91 specimens. The value of stress exponent for all specimens was evaluated, and corresponding mechanisms were discussed. The analyses of microstructures and corresponding impression creep behavior of P91/P91B samples suggested that modification of 100 ppm boron to P91 steel improved creep-rupture ductility that delayed type IV failure at outer HAZ of P91 steel weldments.


2020 ◽  
Vol 134 ◽  
pp. 105506 ◽  
Author(s):  
Zengliang Gao ◽  
Yuxuan Song ◽  
Zhouxin Pan ◽  
Jianan Chen ◽  
Yi Ma

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Guodong Zhang ◽  
Yanfen Zhao ◽  
Fei Xue ◽  
Zhaoxi Wang ◽  
Jinna Mei ◽  
...  

Creep-fatigue interaction is a principal cause of failures of many engineering components under high temperature and cyclic loading. In this work, stress controlled creep-fatigue interaction tests are carried out for modified 9Cr-1Mo (P91) steel. In order to study the damage mechanism of P91 steel under creep-fatigue interaction, Scanning Electron Microscopy (SEM) of specimen fracture morphology and in-situ observation experiments were conducted. Based on the ductility exhaustion theory and creep-fatigue interaction tests data, the modified ductility exhaustion life prediction model was developed. The predicted results are in a good agreement with the experiment. By comparison with frequency separation model, the life predicted by ductility exhaustion model is better than frequency separation model obviously. The results show that different stress amplitude and mean stress have great effect on the fracture damage mechanism when the hold time is invariable. By the SEM analysis of fracture morphology, the damage characters of creep, creep-fatigue interaction and fatigue can be partitioned. The specimen crack initiation source is the modified 9Cr-1Mo steel inclusion. Therefore, this work can provide a reference of life prediction and design for high temperature materials and components.


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