Masato Murata and Yoshihiko Mukai
Faculty of Engineering, Osaka University, Osaka
The existence of critical stresses for SCC initiation, σth and KISCC, is often confirmed in several kinds of chloride solutions. The σth was reported to depend on yield point of materials. On the other hand, the existence of KISCC shows that the passive film can repair on plastic deformed crack tip because of the stress and strain diverging to infinity. This contradiction could not be explained with static mechanics. In this paper, supposing that SCC initiation would occur by dynamic mechanics such as dynamic strain, even in a dead weight condition, the relation between the mechanisms for SCC initiation in smooth and cracked specimens were investigated. As the result, a sort of plastic strain induced by corrosion was detected with mechanochemical methods. This phenomenon seemed to resemble the Rehbinder's effect. The relation between σth and KISCC was explained with this corrosion induced strain concept.
(Received November 12, 1993)
stress corrosion cracking, stainless steel, dynamic strain, σth, KISCC, constant load test, slow strain rate tensile test
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