Stress-Corrosion Susceptibility of High-Strength Steel, in Relation to Fracture Toughness

Abstract

The stress-corrosion susceptibility of several ultrahigh-strength ferrous alloys is described on the basis of fracture-mechanics parameters. Two general conditions were considered: First, the susceptibility of a material at various levels of tensile yield strength and fracture toughness; and second, the susceptibility as a function of applied subcritical stress-intensity levels. Experimentally, a notched and fatigue-cracked bendbar specimen configuration was used. Under a subcritical load, fracture of the specimen occurs upon sufficient environmentally influenced crack extension. The susceptibility criterion adopted in this investigation was the time period to catastrophic fracture of the specimen. The results are evaluated in terms of strength level and fracture toughness, and the usefulness of the data generated is examined in terms of material evaluation and application.