Controlled rolling of skelp on low-power mills

• Published in: Metallurgist (New York) 2004-09, Vol.48 (9-10), p.467-472
• Main Authors: Morozov, Yu. D., fron, L. I., Stepashin, A. M., Shabalov, I. P.
• Format: Article
• Language: English
• ISSN: 0026-0894; 1573-8892
• DOI: 10.1007/s11015-005-0007-0

Large-diameter pipes are one of the most metal-intensive products that are made. Russian industry annually produces 700,000-1,000,000 tons of such pipe just to fill the orders placed by Gazpom. The metal of these pipes must meet exacting standards for strength characteristics, low-temperature toughness, ductility, weldability, and cold resistance. The last property is particularly important, and obtaining it requires the use of a special technology. Cold resistance is determined from the results of drop-weight tear tests (DWTT) of specimens of normal thickness. The percentage of the tough component in the fracture of DWTT specimens tested at the service temperature should be at least 85%. After this requirement was incorporated into existing standards, the number of fractures of gas pipelines decreased sharply, brittle fractures longer than one pipe length were completely eliminated (the number of such fractures previously totalled 100 m or more), and it became possible to transport gas in 1420-mm-diam. pipes with a working pressure of 7.5-10.0 MPa.