Corrosion of titanium alloys in high temperature near anaerobic seawater

• Published in: Corrosion science Vol. 105; pp. 17 - 24
• Main Authors: Pang, Jianjun, Blackwood, Daniel J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2016
• Subjects: Anaerobic; CO2; High temperature; Seawater; Titanium; Titanium; High temperature; CO2; Seawater; Anaerobic
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2015.12.011

•In absence of CO2 Ti grades 2 and 5 suffer crevice corrosion at temperatures 80°C and 200°C.•For Ti grade 5 crevice corrosion can occur as low as 80°C in the presence of CO2.•Ti grade 7 is immune to crevice corrosion in test conditions.•All grades resistant to SCC and pitting in presence of CO2.•Rare earth yttrium additions below 0.2 wt%. for improved mechanical properties are detrimental to corrosions performance.•Analysis of threat of hydrogen induced cracking suggest this is not a threat at a deepsea well head. Grades 2, 5 and Grade 7 were investigated in near anaerobic (<1ppm oxygen) seawater up to 200°C with and without CO2. All three grades were found to resist stress corrosion cracking and pitting corrosion. Grades 2 and 5 suffer crevice corrosion at temperatures 80°C and 200°C respectively. In the presence of CO2 Grade 5 becomes more vulnerable to crevice corrosion, with attack starting at 80°C with preferential dissolution of the beta phase. An analysis of the threat of hydrogen induced cracking leads to the conclusion that this was not a likely threat to any of the Ti alloys investigated.