J. Japan Inst. Metals, Vol. 58, No. 5 (1994),
pp. 507-511

Mechanism of Initiation of Stress Corrosion Cracking in Smooth andPrecracked Sheets of Austenitic Stainless Steels

Masato Murata and Yoshihiko Mukai

Abstract:

The existence of critical stresses for SCC initiation, σ_th and K_ISCC, is often confirmed in several kinds of chloride solutions. The σ_th was reported to depend on yield point of materials. On the other hand, the existence of K_ISCC 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 σ_th and K_ISCC was explained with this corrosion induced strain concept.

(Received November 12, 1993)

Keywords:

stress corrosion cracking, stainless steel, dynamic strain, σ_th, K_ISCC, constant load test, slow strain rate tensile test

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