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The threshold chloride concentrations for solid 316LN stainless steel, 316L stainless steel clad, 2101 LDX duplex stainless steel, MMFX-2 (Fe-9%Cr), and carbon steel (ASTM A615) rebars were investigated through laboratory tests in saturated Ca(OH)2 + NaCl solutions. The chloride threshold for carbon steel was found to be less than a Cl-/OH- molar ratio of 1, which was consistent with the literature. Solid 316LN stainless steel rebar in a pickled condition was found to have a much higher chloride threshold (i.e., threshold Cl-/OH- ratio> 20) than carbon steel (0.25

In an effort to develop relevant data for use in applying damage tolerance analysis concepts to railroad tank cars, the fatigue crack growth (FCG) behavior of TC-128B tank car steel was investigated by SwRI in a previous test program conducted for the Volpe Center. Fatigue crack growth rate data (da/dN vs AK) for TC-128B tank car steel were obtained for two lots of TC-128B steel donated by two tank car manufacturers. In order for these data to be available for use in fatigue crack growth analyses of railroad tank cars, they must be mathematically characterized in terms of crack growth equations or laws. Therefore, the objective of the work reported herein was to obtain empirical constants for crack growth equations that are commonly employed in damage tolerance analyses. These equations are the Paris equation, the Walker equation and the NASGRO(Tradename) equation. In the following, a brief review of the previous fatigue crack growth rate test program is first presented, followed by a summary of the crack growth equations that were used to fit the empirical data. The curve fits to the data for each equation are then presented along with recommendations for their use.