ENVIRONMENT-ASSISTED CRACKING OF AISI 305, AISI 410 STAINLESS STEELS, AND LOW ALLOY STEEL BOLTS/FASTENERS IN CHLORIDE CONTAINING ENVIRONMENTS

摘要

Environment-assisted cracking (EAC) susceptibility of AISI 305 austenitic stainless steel, AISI 410rnmartensitic stainless steel, and low alloy steel ASTM A-325 bolts/fasteners have been determined in arnseries of aggressive sodium chloride containing solutions. The stress corrosion cracking (SCC) testsrnwere conducted using wedge/loaded Disk-Shaped Compact Tension specimens (ASTM E-399), whichrnwere machined from the bolts and totally immersed in solutions maintained either at room temperaturernor at boiling conditions. The solutions were prepared to contain 3.5%, 5%, 25% NaCI in addition to coalrnwith high sulfur content. The pH of some solutions were adjusted to pH = 2.0 via phosphoric acidrnadditions in order to provide more aggressive testing conditions. Crack growth was monitored in orderrnto determine the Threshold Stress Intensity for SCC (Klscc), under the conditions tested. Bothrnfractography and metallography were conducted in order to characterize the crack growth behavior.