Isothermal transformation and precipitation behaviors of titanium microalloyed steels
Xiang‑dong Huo1, Kang He2, Ji‑nian Xia3, Lie‑jun Li4, Song‑jun Chen4
1 School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China; 2 Technology Quality Center, Shandong Iron and Steel Group Laiwu Co., Ltd., Laiwu 271104, Shandong, China; 3 Technology and Quality Center, Shandong Iron and Steel Group Rizhao Co., Ltd., Rizhao 276826, Shandong, China; 4 School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China
Isothermal transformation and precipitation behaviors of titanium microalloyed steels
Xiang‑dong Huo1, Kang He2, Ji‑nian Xia3, Lie‑jun Li4, Song‑jun Chen4
1 School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China; 2 Technology Quality Center, Shandong Iron and Steel Group Laiwu Co., Ltd., Laiwu 271104, Shandong, China; 3 Technology and Quality Center, Shandong Iron and Steel Group Rizhao Co., Ltd., Rizhao 276826, Shandong, China; 4 School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China
摘要 The microstructure transformation and precipitation behavior of nano-carbides in Ti microalloyed steel during isothermal process were studied by a compression test on a Gleeble 3800 thermomechanical simulator and analyzed by optical microscopy, transmission electron microscopy and other methods. The results show that γ→ α phase transformation and TiC precipitation take place in Ti microalloyed steel during the isothermal process, and time–temperature–transformation curve and precipitation–time–temperature (PTT) curve are all of “C”-type. During the isothermal process, the interphase precipitation of TiC mostly occurs at the period of the phase transformation, and the random precipitation of TiC mostly occurs on the ferrite after the phase transformation. The increment in yield strength at the initial stage of isothermal transformation mainly comes from phase transformation strengthening. With the increase in isothermal time, the precipitation hardening effect becomes more important for nucleation and growth of titanium carbides and eventually reaches the maximum value at the precipitation finished point of the PTT curve.
Abstract：The microstructure transformation and precipitation behavior of nano-carbides in Ti microalloyed steel during isothermal process were studied by a compression test on a Gleeble 3800 thermomechanical simulator and analyzed by optical microscopy, transmission electron microscopy and other methods. The results show that γ→ α phase transformation and TiC precipitation take place in Ti microalloyed steel during the isothermal process, and time–temperature–transformation curve and precipitation–time–temperature (PTT) curve are all of “C”-type. During the isothermal process, the interphase precipitation of TiC mostly occurs at the period of the phase transformation, and the random precipitation of TiC mostly occurs on the ferrite after the phase transformation. The increment in yield strength at the initial stage of isothermal transformation mainly comes from phase transformation strengthening. With the increase in isothermal time, the precipitation hardening effect becomes more important for nucleation and growth of titanium carbides and eventually reaches the maximum value at the precipitation finished point of the PTT curve.
Xiang‑dong Huo,Kang He,Ji‑nian Xia, et al. Isothermal transformation and precipitation behaviors of titanium microalloyed steels[J]. Journal of Iron and Steel Research International, 2021, 28(03): 335-345.
2021, Vol. 28 
