Internal hydrogen embrittlement of a ferritic stainless steel

Journal Article · Sat Apr 01 04:00:00 EST 1995 · Metallurgical Transactions, A

DOI:https://doi.org/10.1007/BF02649081· OSTI ID:42857

Huang, J H; Altstetter, C J ^[1]

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1. Univ. of Illinois, Urbana, IL (United States). Dept. of Materials Science and Engineering

AL 29-4-2 ferritic stainless steel was cathodically precharged with hydrogen at 230 C in a molten salt electrolyte. Constant load crack growth tests were performed in air and in hydrogen gas at 108 kPa pressure at room temperature on both uncharged specimens and specimens containing 2 wt ppm hydrogen. The DC potential drop method was calibrated with optical measurements to continuously monitor the crack position, so that the crack velocity vs stress intensity relation could be calculated. From the test results, it was found that dissolved hydrogen does allow subcritical crack growth for tests in air, but its effect is masked by the external hydrogen for tests in hydrogen gas. The distribution of slip bands on the side surface indicates that the dissolved hydrogen causes localization of plasticity, with the strain concentrated in coarse slip bands. Comparing the embrittling effect of internal hydrogen with that of external hydrogen, it can be concluded that environmental hydrogen is far more damaging than internal hydrogen, at least in specimens containing 2 wt ppm hydrogen.

• Sponsoring Organization: USDOE
• OSTI ID: 42857
• Journal Information: Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 4 Vol. 26; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AIR
CRACK PROPAGATION
ELECTROLYTIC CELLS
FERRITIC STEELS
FRACTOGRAPHY
HYDROGEN
HYDROGEN EMBRITTLEMENT
OPTICAL MICROSCOPY
PLASTICITY
POTASSIUM HYDROXIDES
SAMPLE PREPARATION
SODIUM HYDROXIDES
STRESS INTENSITY FACTORS