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.