Sprowls, D. O.
Assistant chief, Alcoa Research Laboratories, New Kensington, Pa.
Pages: 25 Published: Jan 1967
Susceptibility of a metal to stress corrosion implies a greater deterioration of its mechanical properties through the simultaneous action of a static stress and exposure to a corrosive environment than would be produced by the combined effects of each factor operating separately. In recent years this point of view on stress corrosion and stress corrosion cracking (the ultimate in stress corrosion) has become widely recognized. However, confusion still exists, with the result that some work is published that has little value because of the poor design of testing procedure. It is still sometimes erroneously assumed that failure of a specimen under stress corrosion test conditions suffices to demonstrate susceptibility to stress corrosion cracking. This conclusion is unjustified, for the specimen may have become so weakened by corrosion, even without any acceleration by stress, as to fail under the applied load. Thus, it is most essential to select techniques (type of specimen and method of loading, test medium and period of exposure) that produce failure that is purely the result of stress corrosion cracking. Because of the marked effect that test procedure can have upon ordinary criteria, such as specimen life, percentage of specimen survival, threshold stress, etc., investigators should report details of procedure and technique as well as detailed data along with their analysis of the results. This is necessary to enable the reviewer to adapt the information to his need and to make possible a reanalysis of the data by some method that may be developed in the future.
stress corrosion, cracking (fracturing), corrosion, data, evaluation, analysis
Paper ID: STP46466S