Effect of Residual Impurities on Hydrogen Assisted Cracking in High-Strength Steels.
Abstract
Intergranular embrittlement in 4340-type high strength steels (yield strength approximately equal to 200 ksi) have been studied both at 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 H2 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. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 08, 1977
- Accession Number
- ADA051826
Entities
People
- Charles J. Mcmahon Jr.
- Nikhiles Bandyopadhyay
Organizations
- University of Pennsylvania