Effect of Finish Rolling Temperature on the Texture and Fracture Resistance of Low-Carbon High-Strength Pipe Steels during Thermomechanical Treatment

• Published in: Metal science and heat treatment 2023-09, Vol.65 (5-6), p.330-337
• Main Authors: Pumpyanskii, D. A., Pyshmintsev, I. Yu, Lobanov, M. L., Chikalov, S. G., Urtsev, N. V., Denisov, S. V., Urtsev, V. N.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Crystallography; Elongated structure; Engineering Thermodynamics; Finish rolling; Fracture toughness; Gas pipelines; Heat and Mass Transfer; Heterogeneity; High strength steels; Impact analysis; Materials Science; Metal sheets; Metallic Materials; Natural gas; Pipes; Rolling direction; Tension tests; Texture; Thermal and Thermomechanical Treatment; Thermomechanical treatment
• ISSN: 0026-0673; 1573-8973
• DOI: 10.1007/s11041-023-00935-w

Sheets from a pipe steel rolled in the finishing stage of controlled thermomechanical treatment (TMT) above and below the onset temperature of γ → α transformations are studied. The structure and texture of specimens are determined by metallographic analysis; impact bending and tension tests are performed. The structural heterogeneity formed during rolling below A 3 was shown to have a significant effect on the steel structure after controlled cooling. The structure acquires regions of a homogeneous crystallographic texture elongated in the rolling direction, which form preferential sites with the lowest fracture energy for secondary crack propagation. Such processes decrease the total running fracture energy in gas pipelines made of high-strength steels.