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Molinie, Eric; Pineau, A.; Piques, R.

doi:10.1111/j.1460-2695.1992.tb00021.x

Cited by 1 publication

(2 citation statements)

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“…In the aged material the acceleration in creep strain rate could also be related to the presence of intergranular creep cavities. Such cavities were observed but only in the vicinity of cracks present in the casing between steam admission valves [5] or close to creep cracks, as shown in the companion paper The creep rupture curves are given in Fig. 7 where it is observed that the hot part material leads at times to failure 3 or 5 times lower than those corresponding to the cold part material.…”

Section: Creep Behaviourmentioning

confidence: 89%

“…The material was taken from the high temperature turbine casing of a power plant which operated during approximately 30 years (1 50,000 h) at 540°C. The inspection of this component showed the presence of cracks as well as creep cavities in the steam admission part working at the highest temperature (* 540°C) [5]. The assessment of the residual life necessitates therefore the study of creep crack initiation and creep crack growth behaviours which are investigated in the companion paper (Part 11).…”

Section: Introductionmentioning

confidence: 99%

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BEHAVIOUR OF A 1Cr‐1Mo‐0.25V STEEL AFTER LONG‐TERM EXPOSURE–I. CHARPY IMPACT TOUGHNESS AND CREEP PROPERTIES

Moliniéa

Piques

Pineau

1991

Fatigue Fract Eng Mat Struct

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This paper deals with the effect of casting conditions and long-term in-service exposure on the Charpy-V notch and creep properties of a 1Cr-lMo-O.25V steel. The material is investigated under two conditions: (i) as-cast in a thick part which produces a mixed ferrite-bainite microstructure and (ii) as-cast as a small ingot which produces a fully bainitic microstructure. The material from the thick part was taken from either the cold part (-200°C) or the hot part (u54oOC) of a steam power casing which operated for about 150,000 h. A small shift in the ductile-brittle transition temperature is shown after the long exposure time. This shift is related to segregation of phosphorus impurities along the grain boundaries as shown by Auger electron spectrometry. The bainitic microstructure exhibits a much better creep resistance compared to the thick part component material. Moreover, in the latter case, it is shown that long-term in-service exposure induces an increase in creep strain rate and a decrease in creep ductility at least for relatively short times to failure (8 1000 h). These variations in mechanical properties are briefly discussed in terms of microstructural changes. Scanning electron microscopy confirmed that grain boundary cavitation was responsible for decreasing the creep ductility at large times to failure (2 10,000 h).

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Section: Creep Behaviourmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%