Manufacturing technologies of steel seamless tubes for production of hard-to-recover hydrocarbons

The review contains main directions in the development of modern steelmaking, hot rolling technologies and heat treatment aimed to follow increased requirements to seamless tubes for production of oil and gas under severe conditions. New targets of PJSC “Gazprom” in development of new resources have determined new technical requirements to pipes for low temperature application, resistant to hydrogen sulfide and carbon dioxide corrosion. Basic metal science approaches are given to develop new chemical compositions of high quality steels containing minimum of sulfur, phosphorous and solute gases. Corresponding heat treatment routes are determined for formation of martensitic microstructure in full wall section during quenching with subsequent high tempering for required combination of high strength and ductility. It was shown that optimal combination of high strength and toughness at 60 °C below zero can be achieved by alloying of chromium-molybdenum steel containing about 0.25 wt. % of carbon with strong carbon forming elements such as vanadium and niobium. Sustainability of these steels to stress sulfide cracking was achieved through grain refinement with microalloying by molybdenum in concentrations corresponding to strength grades that gives high hardenability and retards tempering of martensite. New compositions of corrosion resistant martensitic 13 % chromium steel were carried out that was resulted in required resistance to carbon dioxide environments with improved low temperature toughness and high strength. The authors present results of reconstruction of steel making and hot rolling production lines at JSC “Volzhskii Pipe Plant” providing the required quality of new products from continuously cast steel billets to finished tubes.