Corrosion-Fatigue Crack Propagation Studies of Some New High-Strength Structural Steels

Abstract

Fatigue crack propagation studies were conducted on three new high-strength structural steels: 9Ni–4Co–0.20C quenched-and-tempered, 10Ni–2Cr–1Mo–8Co dual-strengthened, and 13Cr–8Ni–2Mo precipitation-hardened stainless. The yield strengths of these steels ranged from 176 to 193 ksi. Notched cantilever-bend specimens of each steel were cycled zero-to-tension in two environments, room air and 3.5 percent NaCl salt water. Fatigue crack growth rates were measured experimentally and correlated with the crack tip stress-intensity factor range. The results indicate that these new steels possess greater resistance to fatigue crack propagation and less sensitivity to environment than previously studied steels of comparable strength.