Creep-Fatigue Properties of Mod.9Cr-1Mo Steel Under Variable Straining

1993 ◽  
Vol 115 (3) ◽  
pp. 235-241
Author(s):  
M. Miyahara ◽  
K. Tokimasa
Keyword(s):  
Type Strain ◽  
Life Prediction ◽  
Strain Range ◽  
Fatigue Properties ◽  
Rate Equations ◽  
Creep Fatigue ◽  
Slow Type ◽  
Damage Rule ◽  
High Test ◽  
Life Prediction Model

Two-step variable straining tests, which included CP- (slow-fast) type and PC- (fast-slow) type tests, were conducted at 600°C in air for Mod.9Cr-1Mo steel. In the tests, CP and PC-type strain range level varied from high to low for the high-low test and from low to high for the low-high test. The deviations of the experimental data from the linear damage rule prediction were observed. These experimental results and the effect of the strain waveform on the creep-fatigue properties under variable straining were well explained by the life prediction model previously proposed by the authors in which the strain range partitioned crack growth rate equations were applied.

A Strain Rate Ratio Approach for Assessing Creep-Fatigue Life of 63Sn-37Pb Solder Under Shear Loading

2004 ◽  
Vol 127 (4) ◽  
pp. 407-414 ◽  
Author(s):  
Yutaka Tsukada ◽  
Hideo Nishimura ◽  
Hiroki Yamamoto ◽  
Masao Sakane
Keyword(s):  
Fatigue Life ◽  
Strain Rate ◽  
Rate Ratio ◽  
Life Prediction ◽  
Strain Range ◽  
Shear Loading ◽  
Strain Waves ◽  
Creep Fatigue ◽  
Ratio Approach ◽  
Damage Rule

This paper studies creep-fatigue life prediction under shear loading by making extensive torsion creep-fatigue experiments using four kinds of strain waves. The linear damage rule, strain range partitioning method, frequency modified fatigue life, and ductility exhaustion model were applied to the experimental data, but no methods accurately predicted the creep-fatigue life. A new method based on the strain rate ratio, which predicted the creep-fatigue life within a factor of 4 scatter band, was developed.

Creep-Fatigue Properties of Fe-Ni Base 0.08C-23Cr-45Ni-7W Alloy for Piping in 700°C A-USC Power Plants

2007 ◽  
Author(s):  
Yasutaka Noguchi ◽  
Mitsuo Miyahara ◽  
Hirokazu Okada ◽  
Masaaki Igarashi ◽  
Kazuhiro Ogawa
Keyword(s):  
Crack Initiation ◽  
Type Strain ◽  
Power Plants ◽  
Strain Range ◽  
Inelastic Strain ◽  
Operating Conditions ◽  
Heat Transfer Analysis ◽  
Fatigue Properties ◽  
Creep Ductility ◽  
Creep Fatigue

Creep-fatigue properties of Fe-Ni base 0.08C-23Cr-45Ni-7W alloy (HR6W) are investigated at 700°C and compared with Ni base superalloy Alloy617 in order to examine applicability of these materials to piping in 700°C A-USC power plants. It is clarified that the fatigue lives of HR6W and Alloy617 are almost the same under PP (fast-fast) type strain waveform, but the life of HR6W is longer than that of Alloy617 under CP (slow-fast) type strain waveform. The crack initiation lives at the ligament parts of superheater outlet headers, which are made of HR6W and Alloy617, are predicted from the results of three-dimensional FE-analyses. The transient heat transfer analysis and the elastic-plastic-creep thermal stress analysis are conducted on several kinds of typical operating conditions to evaluate the inelastic strain caused by the thermal cycles during start-up and shut-down of power plants. The maximum steam temperature and pressure are selected as 700°C and 34.3MPa, respectively, and the maximum cycle time of operation is 1 year. On the basis of the analytical results, creep-fatigue and creep rupture properties of the materials, the crack initiation lives of the headers are predicted with the strain range partitioning method. Inelastic strain in the header of HR6W is larger than that of Alloy617, because HR6W has lower creep deformation resistance and a slightly higher thermal expansion coefficient. However the predicted life of the header of HR6W is longer than that of Alloy617, because HR6W is much superior to Alloy617 in creep ductility and creep-fatigue properties.

Creep-Fatigue Properties for Repair Welded Joint

2006 ◽  
Author(s):  
Isamu Nonaka ◽  
Keiji Kubushiro ◽  
Takuya Ito ◽  
Yoshio Takagi
Keyword(s):  
Weld Joint ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Axial Strain ◽  
Strain Range ◽  
Fatigue Properties ◽  
Piping System ◽  
Partial Repair ◽  
Joint Specimen ◽  
Creep Fatigue

Repair welding has been performed when damage has been detected in aged power boiler piping. Discontinuity of deformation ability occurs between the new weld metal and degraded used material in the repair welded joint. Therefore creep-fatigue properties become important under displacement controlled piping system loading. Partial repair welded joint specimen and full repair weld joint specimen were made using the retired 2.25Cr-1Mo steel main steam header. In order to clarify the creep-fatigue properties for two kinds of repair welded joint specimens, fatigue tests under 0.7% strain range with 60min tensile strain dwell were performed at 600C. Both kinds of specimens were necked and fractured at the heat affected zone of welded joint due to the axial strain concentration and ratcheting at heat affected zone. The creep-fatigue life of partial repair weld joint specimen was about half of that of full repair weld joint specimen. This may be due to the low creep-fatigue resistance of the heat affected zone for partial repair welded joint specimen.

Creep-Fatigue Properties of the Candidate Materials of 700°C-USC Boiler

2007 ◽  
Author(s):  
Keiji Kubushiro ◽  
Hiroki Yoshizawa ◽  
Takuya Itou ◽  
Hirokatsu Nakagawa
Keyword(s):  
Hold Time ◽  
Strain Range ◽  
Small Strain ◽  
Fatigue Tests ◽  
Holding Time ◽  
Experimental Results ◽  
Fatigue Properties ◽  
Alloy 617 ◽  
Creep Fatigue ◽  
Cycles To Failure

Creep-fatigue properties of candidate materials of 700°C-USC boiler are investigated. The candidate materials are Alloy 230, Alloy 263, Alloy 617 and HR6W. Creep-fatigue tests were conducted at 700°C and the effect of both strain range and hold time were studied. Experimental results showed that at 1.0% strain range, cycles to failure with 60 min strain holding is about 10% of that without strain holding, but at 0.7% strain range, cycles to failure with 60 min strain holding decreases down to about 1% of without strain holding. It appears that cycles to failure is decreased by increasing strain holding time at all tested strain ranges, and the effect of holding time is emphasized at small strain range. These phenomena depend on the kind of alloys.

scholarly journals Creep-Fatigue Life Prediction for Ligament of Boiler Headers by Strain Range Partitioning Method.

1999 ◽  
Vol 48 (6) ◽  
pp. 604-609 ◽  
Author(s):  
Hiroyuki HAYAKAWA ◽  
Mituo MIYAHARA ◽  
Akihiro KANAYA ◽  
Kazuo OKAMURA
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Strain Range ◽  
Fatigue Life Prediction ◽  
Creep Fatigue

Research on Creep-Fatigue Life Prediction for P92 Steel under Stress-Controlled State

2013 ◽  
Vol 860-863 ◽  
pp. 972-977 ◽  
Author(s):  
De Xian Wang ◽  
Dong Mei Ji ◽  
Jian Xing Ren
Keyword(s):  
Experimental Data ◽  
Life Prediction ◽  
Fatigue Life Prediction ◽  
Effective Coefficient ◽  
P92 Steel ◽  
Modified Model ◽  
Model Predictions ◽  
Creep Fatigue ◽  
Prediction Capability ◽  
Life Prediction Model

Taking the P92 steel as the object,Creep-Fatigue (CF) tests of P92 steel at 873K under stress-controlled were carried out with GWT2504 equipment to investigate the CF life prediction. The life prediction model based on Applied Mechanical Work Density (AMWD) was developed in this study,and introduce the effective coefficient ƞ to modify the former. To verify the prediction capability of the AMWD-based and the modified model, comparisons of the models predicted lives with the experimental data of CF tests on P92 steel at 873K were made, it is found out that the AMWD-based model predictions for CF are in agreement with the experimental lives with the factors of 0.9013 and 1.0600, which verifies the model has a good predictability, and the Modified model with the factors of 0.9558 and 1.0469.

P92 steel creep-fatigue interaction responses under hybrid stress-strain controlled loading and a life prediction model

2020 ◽  
Vol 140 ◽  
pp. 105837
Author(s):  
Tianyu Zhang ◽  
Xiaowei Wang ◽  
Yunnan Ji ◽  
Wei Zhang ◽  
Tasnim Hassan ◽  
...  
Keyword(s):  
Prediction Model ◽  
Life Prediction ◽  
Stress Strain ◽  
P92 Steel ◽  
Creep Fatigue ◽  
Life Prediction Model ◽  
Hybrid Stress
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