Moon Joonoh, Bae Gyuyeol, Jeong Bo-Young, Shin Chansun, Kwon Min-Ji, Kim Dong-Ik, Choi Dong-Jun, Lee Bong Ho, Lee Chang-Hoon, Hong Hyun-Uk, Suh Dong-Woo, Ponge Dirk
Department of Materials Convergence and System Engineering, Changwon National University, Changwon, Gyeongnam, Republic of Korea.
Steel Solution Research Lab., Technical Research Lab., POSCO, Incheon, Republic of Korea.
Nat Commun. 2024 Feb 12;15(1):1301. doi: 10.1038/s41467-024-45470-1.
The degradation of mechanical properties caused by grain coarsening or the formation of brittle phases during welding reduces the longevity of products. Here, we report advances in the weld quality of ultra-high strength steels by utilizing Nb and Cr instead of Ni. Sole addition of Cr, as an alternative to Ni, has limitations in developing fine weld microstructure, while it is revealed that the coupling effects of Nb and Cr additions make a finer interlocking weld microstructures with a higher fraction of retained austenite due to the decrease in austenite to acicular ferrite and bainite transformation temperature and carbon activity. As a result, an alloying design with Nb and Cr creates ultrastrong and ductile steel welds with enhanced tensile properties, impact toughness, and fatigue strength, at 45% lower material costs and lower environmental impact by removing Ni.
在焊接过程中，由于晶粒粗化或脆性相的形成导致的机械性能退化会降低产品的使用寿命。在此，我们报告了通过使用铌（Nb）和铬（Cr）替代镍（Ni）来提高超高强度钢焊接质量的进展。单独添加Cr作为Ni的替代品，在细化焊接微观结构方面存在局限性，而研究表明，由于奥氏体向针状铁素体和贝氏体转变温度以及碳活度的降低，添加Nb和Cr的耦合效应会产生更细的互锁焊接微观结构，且残余奥氏体的比例更高。结果，采用Nb和Cr的合金设计创造出了超强韧性的钢焊缝，其拉伸性能、冲击韧性和疲劳强度得到增强，同时通过去除Ni，材料成本降低了45%，对环境的影响也更小。
