Environmental Cracking of High Strength Maraging Steels: Part I – Aqueous NaCl Solution

Four grades of high strength maraging steel were tested in air and aqueous solutions for susceptibility to stress corrosion cracking and hydrogen embrittlement. Electrochemical methods were used to characterize each alloy and to control the test conditions during slow strain rate tensile tests. Environment sensitive failure was observed under conditions in which either stress corrosion cracking or hydrogen embrittlement mechanisms were likely. The strongest steels were the most susceptible to embrittlement. Hydrogen was readily removed by baking which restores the original properties. Steels in the 'soft' condition were not susceptible. Protective oxide coatings were found to be ineffective in reducing hydrogen embrittlement but they improved the resistance to stress corrosion cracking under the anodic conditions used in these slow strain rate tests.