Oil and Gas industry in the last decades has increased the use and need of heavy wall thickness line pipes, in particular for onshore / offshore high pressures and high temperatures (HP/HT) and offshore deep water / ultra-deep water applications.
The paper presents the results achieved by Tenaris on seamless line pipes in grades X65/X70, according to API 5L / ISO 3183, with wall thickness in a range from 40 to 60 mm and diameter between 6 5/8” and 16”, produced by hot rolling process followed by quenching and tempering. Such line pipes are able to withstand very demanding conditions, like sour environment, very high pressure and wide temperature range.
In this publication, the main outcomes of laboratory testing activities on the mentioned materials will be presented as part of heavy wall line pipe qualification. For this purpose, a special testing program, including mechanical and corrosion tests, has been executed. Material demonstrated an excellent behaviour, exhibiting both mechanical, toughness and stress corrosion properties suitable for the envisaged harsh applications.