Hydrogen-assisted crack growth of A508-2 in high-temperature pressurized reactor-grade water
Based on fractographic evidence the accelerated fatigue crack growth rate seen under certain circumstances at simulated pressurized water reactor grade water in A508-2 forging steel is due to hydrogen assistance. Hydrogen entry into the crack tip region and subsequent high crack growth rate occurs at lower temperatures when the time of the fatigue cycle exceeds a certain limit of the order of seconds. At higher temperatures, close to the reactor operating temperatures, hydrogen entry is possible only at certain intermediate frequencies; the rapid repassivation or crack tip blunting at lower frequencies prevents this effect. At low Delta K-levels hydrogen entry may be too limited to introduce any effect, at higher Delta K-levels the accelerated crack growth rates bendover back to the ASME air line occurs, this being due to a change in crack growth mechanism or electrochemical conditions at the crack tip.
- Research Organization:
- Valtion Teknillinen Tutkimuskeskus, Espoo (Finland). Metallilaboratorio
- OSTI ID:
- 6654433
- Report Number(s):
- PB-82-204389
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
210200* -- Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
36 MATERIALS SCIENCE
360105 -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
CORROSION FATIGUE
CRACK PROPAGATION
EMBRITTLEMENT
FATIGUE
FRACTOGRAPHY
HYDROGEN EMBRITTLEMENT
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MECHANICAL PROPERTIES
PWR TYPE REACTORS
REACTOR MATERIALS
REACTORS
STEEL-ASTM-A508
STEELS
WATER COOLED REACTORS
WATER MODERATED REACTORS