Lookup NU author(s): Lisa Coneyworth,
Dr Alasdair Charles
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The stress corrosion cracking (SCC) of iron base alloys, stainless steels and nickel based alloys exposed to high temperature water environments is influenced by the electrode potential at the specimen surface. In nuclear coolant environments, under free corrosion conditions, this is strongly influenced by the dissolved oxygen content of the water. However, a range of water chemistry conditions can be modelled in the laboratory by utilising small static or refreshed autoclave systems and potentiostatic control of the specimens. Rector pressure vessel steels, pure iron and a wide range of iron base alloys crack during slow strain rate tests in simulated light water reactor environments if the conditions generate high (anodic) potentials or if such potentials are applied by some external means. Susceptibility to cracking is influenced by water temperature, the inclusion content of the steel, the electrode potential, the applied strain and the crack-tip strain rate. Cracks often initiate at sulphide inclusions but can also be initiated at slip-steps and/or corrosion pits. Sulphate contamination of the water enhances cracking for low sulphur content alloys but has little effect if the alloy already contains many sulphide inclusions. The SCC of various stainless steels, alloy 600 and alloy 690 is also influenced by the electrode potential of the samples. The usefulness of slow strain rate testing for providing a semi-quantitative measure of safety and for studying the mechanism of cracking will be discussed.
Author(s): Congleton J, Charles EA
Editor(s): Moody, N., Thompson, A.
Publication type: Conference Proceedings (inc. Abstract)
Publication status: Published
Conference Name: Hydrogen Effects on Material Behaviour and Corrosion Deformation Interactions - Proc. of the International Conference on Hydrogen Effects on Material Behaviour and Corrosion Deformation Interactions
Year of Conference: 2003
Publisher: The Minerals, Metals & Materials Society
Library holdings: Search Newcastle University Library for this item