Stress corrosion cracking of Alloy 600: Overviews and experimental techniques

Experimental techniques used to investigate stress corrosion cracking (SCC) are described, from the use of constant deformation and constant load specimens in static or dynamic autoclaves to the use of slow strain rate tests with slow strain-rate machines coupled with an autoclave. Crack growth rates are investigated with compact tensile specimens and measured with electric methods (direct current potential drop) or by acoustic emission. An overview of the mechanisms of initiation and propagation of SCC is given, together with the influence of some parameters (eg, hydrogen in primary water, metallurgical state, thermal treatment, surface cold working). Modeling of SCC phenomena is also briefly discussed.