Fracture criteria for hydrogen and temper embrittlement in 9Cr1Mo steel

Journal Article · Fri Apr 01 00:00:00 EST 1994 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(94)90146-5· OSTI ID:5119699

Wall, M; Lane, C E; Hippsley, C A ^[1]

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1. AEA Technology, Oxon (United Kingdom). Harwell Lab.

A reduction in ductility and toughness is observed on thermal aging of 9Cr1Mo steels in the temperature range 400--650 C. Previous investigations using tensile tests have shown a synergistic effect of hydrogen on such temper embrittlement. To investigate the mechanisms underlying this effect of hydrogen a series of fracture tests have been undertaken on a commercially produced 9Cr1Mo steel using blunt-notched (SENB) specimens tested in four-point-bend. The results were analyzed to determine the maximum local tensile stress [sigma][sup *][sub F] and the local stress and strain levels at the point of crack initiation as a function of test temperature, hydrogen content and thermal aging. Local fracture stress, rather than [sigma][sup *][sub F], was relatively constant with test temperature, and it is proposed that this parameter, together with local fracture strain, controls the failure mechanism. A dual stress/strain criteria model is proposed, and it is suggested that both hydrogen and temper embrittlement reduce the local fracture stress, indicating an influence on cohesive strength for both mechanisms of embrittlement. 52 refs.

• OSTI ID: 5119699
• Journal Information: Acta Metallurgica et Materialia; (United States), Vol. 42:4; ISSN 0956-7151
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHROMIUM STEELS
FRACTURE PROPERTIES
DESTRUCTIVE TESTING
EXPERIMENTAL DATA
HYDROGEN EMBRITTLEMENT
MATHEMATICAL MODELS
TEMPERING
THEORETICAL DATA
ALLOYS
CHROMIUM ALLOYS
DATA
EMBRITTLEMENT
HEAT TREATMENTS
HIGH ALLOY STEELS
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS TESTING
MECHANICAL PROPERTIES
NUMERICAL DATA
STAINLESS STEELS
STEELS
TESTING
360103* - Metals & Alloys- Mechanical Properties