Residual Life Assessment of 2.25Cr-1Mo Boiler Pipe by Small Punch Creep Test

2006 ◽  
Author(s):  
Junichi Kusumoto ◽  
Akihiro Kanaya ◽  
Toshimi Kobayashi
Keyword(s):  
Residual Life ◽  
Life Assessment ◽  
Creep Life ◽  
Creep Tests ◽  
Assessment Technique ◽  
Small Punch ◽  
Creep Stress ◽  
Uniaxial Creep ◽  
Residual Life Assessment ◽  
Creep Life Assessment

The non-destructive techniques such as the microstructural assessment are usually performed for residual creep life assessment of plant components. Since these techniques have limited accuracy, destructive assessment techniques such as uniaxial creep tests are required to improve the accuracy of the assessment. However, if this type of destructive assessment technique are applied, the sampling and the weld repair damages the material, and also the assessment will become expensive. On the other hand, small punch creep (SPC) test [1,2], which uses miniature-sized specimens, does not cause any serious sampling damages, and its assessment accuracy is high since it is a mechanical assessment technique. However, in applying the SPC test to the residual creep life assessment of the boiler in service, there are some issues to be studied [1,3,4]. In order to apply SPC test to the residual creep life assessment of the 2.25Cr-1Mo steel boiler pipe, the relationship between uniaxial creep stress and the SPC test load has been studied. And the Omega method [5] by SPC test was also studied.

A Study on Estimation of Internal Pressure Creep Life Using Small Punch Creep (SPC) Tests for Boiler Pipes

2009 ◽  
Author(s):  
Toshimi Kobayashi ◽  
Toru Izaki ◽  
Junichi Kusumoto ◽  
Akihiro Kanaya
Keyword(s):  
Internal Pressure ◽  
Residual Life ◽  
Test Results ◽  
Creep Life ◽  
Creep Tests ◽  
Good Correspondence ◽  
Small Punch ◽  
Uniaxial Creep ◽  
Wide Range ◽  
The Relationship

The small punch creep (SPC) test is possible to predict residual creep life at a high accuracy. But, the results of SPC tests cannot be compared with uniaxial creep or internal pressure creep results directly. In this report, the relationship between SPC test results and uniaxial creep test results in ASME A335 P11 (1.25Cr-0.5Mo Steel) was studied. The obtained relationship between SPC load and equivalent uniaxial creep stress formed a simple linear equation under the wide range of test temperature and test period. Then, the SPC results can be compared with uniaxial results by converting SPC loads to the equivalent uniaxial creep stresses. The relationship between SPC test results and internal pressure creep tests results was also studied. The internal creep life of as-received P11 pipe was almost same as SPC result when the hoop stress was converted to the SPC load. The creep lives of internal pressure creep influenced materials also showed good correspondence with SPC results. Therefore SPC can estimate the residual life of internal pressure creep influenced materials.

Residual Life Assessment Technique Based on Small punch creep test

2004 ◽  
Vol 2004 (0) ◽  
pp. 179-180
Author(s):  
Masataka NAGAE ◽  
Satoshi OGAWA ◽  
Akihiro KANAYA ◽  
Toshimi KOBAYASHI ◽  
Makoto HARADA
Keyword(s):  
Creep Test ◽  
Residual Life ◽  
Life Assessment ◽  
Assessment Technique ◽  
Small Punch ◽  
Residual Life Assessment ◽  
Small Punch Creep Test

Residual Life Assessment of In-Service High Temperature Components by Small Punch Creep Test

2007 ◽  
Author(s):  
Jianhua Shan ◽  
Xiang Ling ◽  
Zhenmai Qian
Keyword(s):  
High Temperature ◽  
Residual Life ◽  
Assessment Method ◽  
Life Assessment ◽  
Analysis Method ◽  
Creep Life ◽  
Uniaxial Creep ◽  
Life Analysis ◽  
High Temperature Components ◽  
Residual Life Assessment

The knowledge of mechanical long term behaviour under static loading for high temperature components requires methodologies for residual life assessment in order to employ the full potential of materials, particularly in non-destructive methods. In this paper, in order to apply small punch creep (SPC) test to the residual creep life assessment of in-service high temperature components, a variety of SPC tests for Cr5Mo steel in a protective Argon atmosphere were carried out, which used disc test specimens of 10mm in diameter and 0.5mm in thickness extracted both new material and in-service high temperature components. The relationship of the creep deflection curve, the test load, rupture time and ductility of miniature specimens were investigated. Based on SPC test and finite element numerical analysis methods, a novel residual life assessment method was proposed to substitute conventional uniaxial creep life analysis method by introducing an initial creep damage parameter. Moreover, the fractographic observation and the structural damage detection analysis were examined. Finally, the results using conventional uniaxial creep life analysis method were studied to validate the reliability of SPC life assessment method.

High-temperature oxidation and the prediction of creep life for 0.5Cr-0.5Mo-025V steel

2001 ◽  
Vol 36 (4) ◽  
pp. 421-437 ◽  
Author(s):  
M Evans
Keyword(s):  
Small Diameter ◽  
Inert Atmosphere ◽  
Life Assessment ◽  
Original Design ◽  
Creep Life ◽  
Creep Tests ◽  
Temperature Oxidation ◽  
Test Conditions ◽  
Uniaxial Creep ◽  
Creep Life Assessment

Creep life assessment of thick-sectioned components such as steam pipes and headers have traditionally been made from uniaxial creep tests conducted in air on specimens of relatively small diameter. As a consequence of oxidation, such creep life assessments although safe are likely to underestimate the available life of such components. Owing to economic pressures there is currently a great need to quantify the size of this conservatism so that such components can be safely operated beyond their original design life. Yet there are few inert atmosphere data available from which this can be directly achieved. This paper suggests a way of incorporating oxidation data into the 0 projection method so as to enable life predictions of thick-sectioned pipes (where the effects of oxidation can be ignored) to be made from short-term tests conducted in air on small-diameter specimens. The paper shows that the resulting model is capable of analysing results from tests conducted in air under test conditions that give a life of up to 100 h and from this accurately predicting the life of thick-sectioned specimens (oxide free) operating under stress-temperature conditions that give a creep life of up to 60000 h. The proposed method for adjusting these predictions to produce estimates of the life of small-diameter specimens operating in air at test conditions giving a life of up to 60000 h is also shown to work well.

scholarly journals Creep Life Assessment of USC Boiler Tubes

2018 ◽  
Author(s):  
Keiji Kubushiro
Keyword(s):  
Life Assessment ◽  
Austenitic Steels ◽  
Ferritic Steels ◽  
Creep Life ◽  
Creep Tests ◽  
Life Evaluation ◽  
Boiler Tubes ◽  
Long Time ◽  
Creep Life Assessment ◽  
Short Time

CSEF (creep strength enhanced ferritic) steels and austenitic steels are widely used for USC boiler tubes. It is important to evaluate creep life of these parts because metal temperature is indeterminable in superheater and reheater tubes. Almost investigations were conducted under higher stress, short time creep tests, but the pressure for the boiler pipe and tube at actual plant were very low. It is therefore necessary to establish creep life method under long time region time test at various stresses. The purpose of this work is to establish creep life evaluation in high Cr ferritic steels and austenitic steels with long time creep ruptured data. The creep life evaluation methods are based on hardness and microstructure changes.

A creep life assessment method for boiler pipes using small punch creep test

2009 ◽  
Vol 86 (9) ◽  
pp. 637-642 ◽  
Author(s):  
Toru Izaki ◽  
Toshimi Kobayashi ◽  
Junichi Kusumoto ◽  
Akihiro Kanaya
Keyword(s):  
Creep Test ◽  
Assessment Method ◽  
Life Assessment ◽  
Creep Life ◽  
Small Punch ◽  
Creep Life Assessment ◽  
Small Punch Creep Test

A criterion of crazing density for the residual life assessment of PMMA during creep

2015 ◽  
Vol 11 (4) ◽  
pp. 517-526 ◽  
Author(s):  
Zongzhan Gao ◽  
Qinghai Li ◽  
Yi Wang
Keyword(s):  
Design Methodology ◽  
Room Temperature ◽  
Residual Life ◽  
Life Assessment ◽  
Initiation Time ◽  
Creep Life ◽  
Content Type ◽  
Life Model ◽  
Residual Life Assessment ◽  
New Criterion

Purpose – A series of creep experiments were carried out to study a new criterion for creep residual life assessment of PMMA (MDYB-10) with various stresses level at room temperature. A macroscopical creep life model based on abundant experiments results was researched first. The model included three phases which are described by the Chen theory, Norton formula and exponential expression, respectively. The paper aims to discuss these issues. Design/methodology/approach – During the creep experiments, the simple optical testing instrument was used to observe the crazing initiation and quantify the crazing damage density in the specimens. Findings – It was shown that the initiation time of crazing damage depended on the stress level, and the crazing damage density increased non-linearly with experiment time. The crazing initiation time equation and damage density equations were expressed. Originality/value – Comprehensive consideration of the creep life model and crazing density evolution equation, a new criterion for creep residual life assessment was introduced. The criterion could be applied to assess the residual life for MDYB-10 by measuring the crazing damage density.

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