METHOD FOR PRODUCTION OF 13CR TYPE MARTENSITIC STAINLESS STEEL SEAMLESS PIPES Russian patent published in 2021 - IPC B21B17/02 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy and can be used in the manufacture of seamless pipes from high-alloy stainless steel of the martensitic class of 13Cr type, used in the fields for the production of oil and gas with a high concentration of carbon dioxide, including in cold climatic conditions. Method for production of seamless pipes from a high-alloy stainless steel billet of the martensitic class of the 13Cr type with a chromium content of 10÷15% includes helical rolling of the billet into a sleeve and deformation of the sleeve on a retained mandrel in a rolling mill. The pipes are rolled out on the retained mandrel at the speed of the mandrel movement in accordance with a mathematical expression. After rolling, pipes are heated for austenitization to a temperature of 900÷980°C, cooling at a rate of at least 00,2°C/sec, at least one subsequent high tempering at a heating temperature of 550÷720°C and cooling in calm air.

EFFECT: invention ensures optimal matching of the speeds of the mandrel and pipe during rolling and improves the quality of pipes by ensuring the required level of strength and viscoplastic characteristics.

3 cl