Creep lifetime prediction of 9Cr-1Mo (grade T91) steel via small punch creep tests and hierarchical multiscale analysis

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.

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Assessment of power law creep constants of Gr91 steel using small punch creep tests

Fatigue & Fracture of Engineering Materials & Structures ◽

10.1111/j.1460-2695.2009.01394.x ◽

2009 ◽

Vol 32 (12) ◽

pp. 951-960 ◽

Cited By ~ 33

Author(s):

Y. W. MA ◽

S. SHIM ◽

K. B. YOON

Keyword(s):

Power Law ◽

Creep Tests ◽

Small Punch ◽

Power Law Creep

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

Volume 6: Materials and Fabrication, Parts A and B ◽

10.1115/pvp2008-61401 ◽

2008 ◽

Cited By ~ 1

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.

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