Manufacture of rolled products for 762-mm-diam. Cold-resistant conductor pipe having a wall thickness of 38.1 mm and an X56 strength rating; Analysis of the tube conversion for this product

Specialists at the company Severstal’ and the Central Research Institute of Ferrous Metallurgy have developed a chemical composition and technology for making steel of strength class X56, and they have also produced a commercial batch of this steel. Production of the batch on the 5000 mill at Severstal’ entailed the use of a modern controlled-rolling technology together with accelerated cooling, which made it possible to obtain the required set of characteristics in thick plates. The Vyksa Metallurgical Plant converted the plates into 762-mm-diam. conductor pipe with a wall thickness of 38.1 mm. Analysis of the effect of the tube conversion on the mechanical characteristics of the steel showed that the changes which take place in the mechanical characteristics of the base metal during the formation of thick-walled tubes must be taken into account when specifications are developed for the flat-rolled products used to make these tubes.