Evaluation of a Proposed Standard Method of Testing for Susceptibility to Stress-Corrosion Cracking of High-Strength 7XXX Series Aluminum Alloy Products
SourceA task group sponsored jointly by The Aluminum Association and the ASTM has recommended a standard method of test for susceptibility to stress-corrosion cracking (SCC) of 7XXX aluminum alloy products (ASTM G 47-76). The proposed standard is a comprehensive method that specifies the corrosive environment and period of exposure, type of test specimen and method of loading, procedures for sampling various manufactured product forms, and guidelines for interpretation of test results. Final selection of test procedures was based on round robin tests performed in nine different laboratories and 3-year exposures to the atmosphere in both seacoast and inland industrial locations. A summary of test results is given to illustrate how the relative performance of three different tempers of 7075 alloy plate can be influenced by the choice of a test specimen, differences in the outdoor atmosphere, and interlaboratory variations in performing the standard 3.5 percent sodium chloride alternate immersion test.