Разработка и освоение в ПАО МММК технологий производства стального проката нового поколения для магистральных трубопроводов

In view of arising needs of Russian oil and gas sectors, elaboration and implementation into series production competi­tive pipe products became an actual task for domestic enterprises of metallurgical industry. Generalized results of elaboration of chemical compositions and automated technologies of sheet rolled stock of new generation production from low-alloyed pipe steels of various strength classes at PJSC MMK presented. It was shown that the selected chemical compositions ensure forming finedispersed ferrite-bainite structure with bainite of granular morphology in a wide range of cooling rates. The elaborated technological modes of sheet rolled stock production from pipe steels stipulate for elimination considerable growth of austenite grain at heating before the rolling, refinement of austenite grains due to recrystallization processes, forming of extensive subgrain structure of austenite at plastic deformation, forming disperse structures during phase transformation in the process of controlled accelerated cooling; forming of extensive fragmented structure in а-phase. The level of strength, tough-plastic properties and resistance against brittle destruction (based on results of tests with a falling weight with determination of tough component share in the break of full-thickness samples) of sheet rolled stock of pipe steels with various chemical composition of PJSC MMK production was demonstrated. Results of study of tests the sheet rolled stock of high-strength steels for pipes of large diameter presented. Objects of the elaborated pipe steels implementation indicated.