REVALUATION OF CONSTANT STRAIN TEST METHOD FOR STRESS CORROSION CRACKING.

Among three well known test methods for SCC (stress corrosion cracking), i. e. , constant total strain, constant load and constant strain rate ones, the first is most commonly used as a preliminary searching method because of cheapness and convenience. But it only supplies a rough qualitative measure of susceptibility to SCC. Nevertheless, if attention is focused on the so-called ″time to crack initiation″ , which is one of the most meaningful factors in a practical engineering design, the method will give full play to its effectiveness because the stresses remain constant until crack initiation. From this viewpoint, the authors examined some problems associated with this test method in order to obtain more reliable and reproducible data. Tests were carried out at various temperatures ranging from the boiling point to the solubility limit of corrodents, on two kinds of stainless steels.