Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Effect of residual impurities on hydrogen-assisted cracking in high-strength steels. Final report, 8 December 1976--7 December 1977. [Type 4340, 77K and room temperature]

Technical Report ·
OSTI ID:6580641
Intergranular embrittlement in 4340-type high strength steels (yield strength approximately equal to 200 ksi) has been studied at both room temperature and 77 K. The toughness trough which is the manifestation of one-step temper embrittlement was absent in a high-purity steel at room temperature, but it appeared in the 77 K tests. The room-temperature test produced no intergranular fracture, but some intergranular facets were found in the 77 K specimens. For commercial steels, the toughness trough occurred in both the room temperature and the 77 K tests. Intergranular fracture in the high-purity steel can be produced at room temperature by charging cathodically with hydrogen in sulfuric acid solution. Hydrogen-assisted cracking in the high purity steel showed a high K sub th value (approximately equal to 72 ksi sq root in) in 1 atm H/sub 2/ at room temperature, which is about a factor of three greater than that observed in any commercial steels. Hence, in this type of steel the resistance to hydrogen-induced cracking can be greatly increased by bringing the impurity effects under control.
Research Organization:
Pennsylvania Univ., Philadelphia (USA). Dept. of Metallurgy and Material Science
OSTI ID:
6580641
Report Number(s):
AD-A-051826
Country of Publication:
United States
Language:
English