Impact Toughness of High-Strength Low-Alloy Steels Joined by Friction STIR Welding

• Published in: Russian physics journal 2024-09, Vol.67 (9), p.1356-1363
• Main Authors: Dolzhenko, A. S., Lugovskaya, A. S., Malopheyev, S. S., Belyakov, A. N.
• Format: Article
• Language: English
• Subjects: Carbon content; Carbon steels; Condensed Matter Physics; Friction stir welding; Hadrons; Heavy Ions; High strength low alloy steels; Impact strength; Lasers; Martensitic stainless steels; Mathematical and Computational Physics; Microstructure; Nuclear Physics; Optical Devices; Optics; Photonics; Physics; Physics and Astronomy; Room temperature; Steel plates; Theoretical; Toughness; Ultrafines; Warm rolling
• ISSN: 1064-8887; 1573-9228
• DOI: 10.1007/s11182-024-03254-6

The microstructure and impact toughness of high-strength low-alloy steels joined by friction stir welding are studied. The hardened steel samples are tempered at a temperature of 600–650°C for 1 hour, followed by warm rolling to a total strain of 1.5 at the same temperature. The resulting steels are characterized by an ultrafine-grained lamella-type microstructure. The as-processed steel plates are joined by friction stir welding. A martensitic microstructure is formed in the stir zone. The steel samples with a carbon content of 0.15% show high impact toughness of 68 J/cm 2 at room temperature with a gradual decrease to 16 J/cm 2 at a temperature of –196°C, while the steel samples with a carbon content of 0.36% exhibit an impact toughness of 10 J/cm 2 at room temperature. The 0.36% carbon steel joints are tempered at a temperature of 650°C for 1 hour, which increases their room-temperature impact toughness to 67 J/cm 2 .