Corrosion-Fatigue Cracking in HY-80 and HY-130 Steels
Memorandum rept. Oct 2011-Sep 2014
NAVAL RESEARCH LAB WASHINGTON DC MATERIALS SCIENCE AND TECHNOLOGY DIV
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An investigation was carried out to characterize the effects of environment including NaCl concentration and load ratio on fatigue crack growth kinetics of HY-80 and HY-130 steels. Fracture mechanics wedge-opening-load WOL specimens oriented in the longitudinal direction LT were used in the current study. The test environments were vacuum, ambient air, and saltwater with NaCl concentrations ranging from 0.1 to 15. Three load ratios, corresponding to R 0.1, R 0.5, and R 0.85, were examined. The results indicate 1 the fatigue crack growth rates and fatigue crack growth threshold, Kth, for HY-80 steel and HY-130 steel are comparable at similar stress ratios in each of the three test environments vacuum, ambient air, and 1 NaCl solution 2 in the low stress intensity region, the fatigue crack growth rates of both HY-80 steel and HY-130 steel are higher and Kth are lower at a high load ratio than those obtained at lower load ratios 3 the fatigue crack growth rates of HY-80 steel and HY-130 steel obtained in ambient air and in 3.5 NaCl solution are comparable and are significantly higher than those obtained in vacuum 4 the fatigue crack growth responses of HY-130 steel are not affected by the change in NaCl concentration and 5 cathodic protection of HY-130 steel in saltwater does not lower its corrosion-fatigue cracking resistance.
- Properties of Metals and Alloys