Effect of Cu and B addition on tempering behavior in the weld CGHAZ of high strength low alloy plate steel

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 497; no. 1; pp. 153 - 159
• Main Authors: Moon, Joonoh, Kim, Sanghoon, Lee, Jongho, Hwang, Byoungchul, Lee, Chang Gil, Lee, Changhee
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.12.2008; Elsevier
• Subjects: Applied sciences; Cu particle; Exact sciences and technology; Hardening. Tempering; Heat affected zone; Heat treatment; Joining, thermal cutting: metallurgical aspects; Metals. Metallurgy; Precipitation; Production techniques; Tempering; Toughness; Welding; Cu particle; Precipitation; Toughness; Heat affected zone; Tempering; Copper addition; Vickers hardness; High strength alloy; Mechanical properties; Low alloy steel; Weld; Fracture toughness; Charpy impact test; Coarse grain structure; Martensitic transformation; Boron addition
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2008.06.031

To understand the effect of Cu and B on mechanical properties of the weld coarse-grained heat-affected zone (CGHAZ) of high strength low alloy plate steels, six alloys including different Cu and B content were prepared. The CGHAZ and tempered conditions were simulated by a Gleeble simulator and mechanical properties were measured by Vickers hardness test and charpy impact test. Toughness of as-welded specimens was deteriorated with comparing to base steels and decreased with increasing Cu + B content. Meanwhile, Vickers hardness showed an opposite tendency, which is due to formation of martensite in the weld CGHAZ. For as-tempered conditions, Vickers hardness at first decreased with increasing tempering temperature and then was reinforced at around 550 °C with an unexpected decrease of toughness, which was mainly due to the precipitation of Cu particles and carbides, such as (Ti, Nb)C and (Mo, Mn) 2C.