Mastering the rolling of plates of strength class K52 for welded gas- and oil-line pipe made of dispersion-hardened steels

A technology has been developed for the controlled rolling of 8-10-mm-thick plates of steel 09GSF to make oil-line pipe with a high resistance to corrosion and cold. The studies that were performed have shown that it is possible to produce skelp of strength class K52 by using steels with a manganese content that is considerably lower (by 0.5-0.7%) than that of steels 17G1S and 17G1S-U. The decrease in manganese content is compensated for by the addition of dispersion-hardening elements to the steel. A comparative evaluation of the efficiency of the dispersion-hardening of steel with vanadium and niobium showed that the required set of service properties is more readily obtained by microalloying with niobium than with vanadium. Steel with a base chemical composition corresponding to grade 09GSF can be used as a foundation for developing steels for gas-line pipes, including pipes suited for "northern" service. The fractures of Charpy and DWTT specimens of these steels are to have a specified percentage of the fibrous component.