The effect of strain-rate and cathodic potential on the tensile ductility of X-65 pipeline steel

• Published in: Corrosion science 1983, Vol.23 (2), p.101-123
• Main Authors: Hinton, B.R.W., Procter, R.P.M.
• Format: Article
• Language: English
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/0010-938X(83)90110-5

The combined effects of cathodic potentials and slow, monotonic straining on the tensile ductility and fracture morphology of X-65 pipeline steel parent plate have been investigated in aerated 3.5% NaCl solution. The results obtained indicate that under the combined influence of very low potentials and very slow strain-rates the reduction in area of X-65 steel during tensile testing can fall from the air value of about 75% to below 20%. The embrittlement, which is shown to be the result of cracking caused by cathodically evolved hydrogen, is less severe at less negative potentials and faster strain-rates, and is not observed at and above potentials of − 0.8 V(SCE). The fracture morphology is also markedly affected by both potential and strain rate and, depending on the values of these parameters, either surface-initiated or internal, transgranular, cleavage-type cracking is observed.