Assessment of Heat-to-Heat Variation of Gr.91 Boiler Pipings by Small Punch Creep Test

2018 ◽  
Author(s):  
Shin-ichi Komazaki ◽  
Keisuke Obata ◽  
Masato Tomobe ◽  
Masatsugu Yaguchi ◽  
Akihiro Kumada
Keyword(s):  
Creep Test ◽  
Power Plants ◽  
Rupture Strength ◽  
Rupture Life ◽  
Creep Property ◽  
Type Specimen ◽  
Testing Technique ◽  
Small Disk ◽  
Small Punch ◽  
Uniaxial Creep

The small punch (SP) testing technique was applied to five heats of Gr.91 steel, which had been actually used for boiler pipings in different ultra-super critical (USC) power plants for long periods of time, to investigate the applicability of this testing technique to the assessment of heat-to-heat variation of creep property. The SP creep test was carried out at the temperature of 650°C and under the loads of 190, 230, 300 N using a small disk-type specimen (ϕ 8 × 0.5 mm). The experimental results revealed that the SP creep rupture strength (rupture life) and the deformation rate were different depending on the heat. These differences were qualitatively in good agreement with those observed in the uniaxial creep test. The results obtained in this study indicated that the SP creep testing technique could be a strong tool for the assessment of heat-to-heat variation of in-service boiler pipings.

Creep Property Evaluation of Heat-Resistant Steels by Small Punch Creep Test

2007 ◽  
Vol 539-543 ◽  
pp. 4434-4439 ◽  
Author(s):  
Shinichi Komazaki ◽  
T. Nakata ◽  
Takayuki Sugimoto ◽  
Yutaka Kohno
Keyword(s):  
Creep Test ◽  
Ferritic Steel ◽  
Rupture Strength ◽  
Creep Property ◽  
Type Specimen ◽  
Standard Test ◽  
Creep Rupture ◽  
Ferritic Steels ◽  
Small Punch ◽  
Property Evaluation

The recently developed small punch (SP) creep test was applied to four different heatresistant ferritic steels, namely, two kinds of conventional ferritic steels which had been actually used in the high-temperature components for long periods and two advanced high chromium ferritic steels for fusion reactor materials to investigate the applicability of the SP creep test. The ratio of the load of SP creep test to the stress of standard uniaxial creep test was calculated so that both the creep rupture curves (load/stress versus Larson-Miller parameter curves) were overlapped to convert the results of SP creep test into those of standard test. As a result, the ratio was determined to be 2.4, irrespective of the kind of ferritic steel. This result indicates that the creep rupture strength of heat-resistance ferritic steels can be estimated using a miniaturized plate-type specimen and this conversion coefficient 2.4 independent of the kind of ferritic steel.

Creep property measurement of service-exposed SUS 316 austenitic stainless steel by the small-punch creep-testing technique

2002 ◽  
Vol 17 (8) ◽  
pp. 1945-1953 ◽  
Author(s):  
Maribel L. Saucedo-Muñoz ◽  
Shin-Ichi Komazaki ◽  
Toru Takahashi ◽  
Toshiyuki Hashida ◽  
Tetsuo Shoji
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Creep Test ◽  
Creep Resistance ◽  
Creep Property ◽  
Creep Rupture ◽  
Secondary Creep ◽  
Small Punch ◽  
Uniaxial Creep ◽  
Small Punch Creep Test

The creep properties for SUS 316 HTB austenitic stainless steel were evaluated by using the small-punch creep test at 650 °C for loads of 234, 286, 338, 408, and 478 N and at 700 °C for loads of 199 and 234 N. The creep curves, determined by means of the small-punch creep test, were similar to those obtained from a conventional uniaxial creep test. That is, they exhibited clearly the three creep stages. The width of secondary creep stage and rupture time tr decreased with the increase in testing load level. The creep rupture strength for the service-exposed material was lower than that of the as-received material at high testing loads. However, the creep resistance behavior was opposite at relatively low load levels. This difference in creep resistance was explained on the basis of the difference in the creep deformation and microstructural evolution during tests. It was also found that the ratio between the load of small-punch creep test and the stress of uniaxial creep test was about 1 for having the same value of creep rupture life.

Small Punch Creep Testing Technique for Remnant Life Assessment

2014 ◽  
Vol 592-594 ◽  
pp. 739-743 ◽  
Author(s):  
J. Ganesh Kumar ◽  
K. Laha ◽  
M.D. Mathew
Keyword(s):  
Creep Test ◽  
Rupture Life ◽  
Life Assessment ◽  
Test Results ◽  
Creep Tests ◽  
Testing Technique ◽  
Creep Properties ◽  
Small Punch ◽  
Miniature Specimens ◽  
Deflection Rate

Small punch creep (SPC) testing technique is a material non-intensive testing technique for evaluating creep behavior of materials using miniature specimens. It can be used for remnant life assessment (RLA) studies on components in service, by scooping out limited material for testing without impairing the strength of component. In order to ensure the reliability of use of SPC technique for RLA, it is necessary to establish sound database on SPC properties of the material before putting into service. In this investigation, SPC technique was used to evaluate creep properties of 316LN stainless steel using specimens of size 10 x 10 x 0.5 mm. SPC tests were conducted in load controlled mode at 923 K and at various loads. SPC curves clearly exhibited primary, secondary and tertiary creep stages. The minimum deflection rate increased and rupture life decreased with an increase in applied load. Like in conventional creep test results, the minimum deflection rate obeyed Norton’s power law and Monkman-Grant relationship. SPC test was correlated with corresponding conventional creep test. Good correlation was established between creep rupture life values evaluated from SPC tests and conventional creep tests.

EFFECT OF BORON ON CREEP DUCTILITY AND CREEP RUPTURE LIFE IN 9CR-1.5MO STEEL

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2490-2495 ◽  
Author(s):  
BUMJOON KIM ◽  
JIWOO IM ◽  
MOON K. KIM ◽  
JONGHOON LEE ◽  
BYEONGSOO LIM
Keyword(s):  
Creep Test ◽  
Rupture Life ◽  
General Concept ◽  
Creep Rupture ◽  
Displacement Rate ◽  
Boron Addition ◽  
Creep Ductility ◽  
Small Punch ◽  
Uniaxial Creep ◽  
The Relationship

In this study, the relationship between the creep ductility and rupture life of 9 Cr -1.5 Mo steel with boron addition at 600°C was investigated by small punch (SP) creep test from the viewpoint of the modified Monkman-Grant relation. The amount of boron addition ranged from 0.0076wt% to 0.0196 wt%. The general concept of Monkman-Grant ductility for uniaxial creep was introduced and then particularly modified for the SP creep. The microstructure of the steel was observed to analyze the effect of boron addition on the creep ductility and rupture life. Based on the modified Monkman-Grant ductility for SP creep, it was found that the boron addition improved the creep ductility and rupture life of the 9 Cr -1.5 Mo steel. Also, the relationship between the minimum creep displacement rate and the amount of boron addition was analyzed.

Development of small bulge fatigue testing technique using small disk‐type specimen

2019 ◽  
Vol 43 (3) ◽  
pp. 444-456
Author(s):  
Shin‐ichi Komazaki ◽  
Ryuichiro Jojima ◽  
Nanna Muraoka ◽  
Shuhei Nogami ◽  
Masayuki Kamaya ◽  
...  
Keyword(s):  
Fatigue Testing ◽  
Type Specimen ◽  
Testing Technique ◽  
Small Disk

Small Punch Creep Properties of Heat Affected Zones of Reduced Activation Ferritic Steel

2008 ◽  
Author(s):  
Taichiro Kato ◽  
Shin-Ichi Komazaki ◽  
Yutaka Kohno ◽  
Hiroyasu Tanigawa
Keyword(s):  
Base Metal ◽  
Creep Test ◽  
Ferritic Steel ◽  
Electron Beam Welding ◽  
High Stress ◽  
Creep Rupture ◽  
Creep Tests ◽  
Creep Properties ◽  
Small Punch ◽  
Uniaxial Creep

The small punch (SP) creep test was carried out at the temperatures of 823∼923 K by using a further miniaturized specimen, namely, TEM disk-type specimen (φ 3.0×t0.25 mm). The tests were applied to the fine grain heat affected zone (FGHAZ), tempered HAZ (THAZ) and base metal (BM), respectively, which were removed from the joint of the reduced activation ferritic steel welded by an electron beam welding, in order to investigate the creep properties of such local regimes. The results obtained from the SP creep test were correlated with those of uniaxial creep tests using the base metal (BM) and welded joint (WJ). Experimental results revealed that there were no large differences between the SP creep rupture strengths of the FGHAZ and THAZ and that of the BM at the relatively high load levels. This result was in good agreement with the fact that the uniaxial creep strength of the WJ was almost coincident with that of the BM at the relatively high stress levels. In addition, the ratio of load (P) to stress (σ), which gave same rupture time, was calculated by using the creep rupture data of the BMs. As a result, the ratio was determined to be 0.43, resulting in the following equation; P = 0.43 σ.

Development of New Small Bulge Fatigue Testing Technique Using Small Disk-Type Specimen

2017 ◽  
Vol 2017 (0) ◽  
pp. OS1213
Author(s):  
Shin-ichi KOMAZAKI ◽  
Ryuichiro JOJIMA ◽  
Nanna MURAOKA ◽  
Shuhei NOGAMI ◽  
Masayuki KAMAYA ◽  
...  
Keyword(s):  
Fatigue Testing ◽  
Type Specimen ◽  
Testing Technique ◽  
Small Disk

Evaluating of creep property of distinct zones in P92 steel welded joint by small punch creep test

2013 ◽  
Vol 47 ◽  
pp. 677-686 ◽  
Author(s):  
Lei Zhao ◽  
Hongyang Jing ◽  
Lianyong Xu ◽  
Yongdian Han ◽  
Junjie Xiu ◽  
...  
Keyword(s):  
Creep Test ◽  
Welded Joint ◽  
Creep Property ◽  
P92 Steel ◽  
Small Punch ◽  
Small Punch Creep Test

Development of Compact Small Punch Creep Testing Equipment

2011 ◽  
Author(s):  
Hajime Watanabe ◽  
Akihiro Kanaya ◽  
Junichi Kusumoto ◽  
Takafumi Tsurui
Keyword(s):  
Power Plant ◽  
Thermal Power Plant ◽  
Power Plants ◽  
Residual Life ◽  
Thermal Power ◽  
Creep Property ◽  
Testing Equipment ◽  
Creep Testing ◽  
Small Punch ◽  
Life Evaluation

Japan has many aged thermal power plant facilities and some boilers in such facilities have been in operation for more than 100,000 hours, so the importance of creep residual life evaluation of components exposed to severe conditions has been increasing. Although creep residual life of such components can be evaluated by destructive methods relatively accurately, they significantly affect the component to be sampled, take a long time to carry out and are high-cost. To solve these problems, Kobe Material Testing Laboratory Co., Ltd. and Kyushu Electric Power Co., Inc. have jointly developed compact-sized and less expensive small punch creep testing equipment for accurate creep residual life evaluation. Outer dimensions of developed equipment are 660W × 335D × 807H (mm); weight is 130kg. Small punch creep test can be conducted by this testing equipment, in order to identify creep property using 8mm diameter and 0.5mm thickness specimens taken from tubes or pipes of thermal power plant facilities, and evaluate remaining life. The testing equipment is expected to improve efficiency and reduce costs to evaluate material characteristics and creep residual life for facilities in power plants and various industries.

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