The fracture toughness properties of A285 steels are being measured at specific material and test conditions for application to elastic-plastic fracture mechanics analysis of storage tanks at the Department of Energy Savannah River Site (SRS). Materials for testing were selected over ranges based on compositions that span the tank plates. Property measurements focus on J-R curve testing in order to characterize ductile fracture behavior of these materials at operational temperatures. The results show a strong loading rate effect, but minimal thickness and temperature effects in the ranges tested. The results from compact tension fracture toughness testing suggest that the initial load carrying capacity and the initial resistance to ductile tearing increases with increasing loading rate. However, this strain rate sensitivity could lead to the unexpected onset of cleavage fracture after some amount of ductile tearing. Testing of archival material at high strain rates revealed that stable ductile tearing was interrupted by cleavage fracture. Ongoing testing will be done to complete the test matrix to complement additional and complete microstructural analysis. The influence of each of the variables on fracture toughness as well as the occurrence of cleavage fracture will be analyzed when the testing is complete.
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