Study on microstructure transformation behavior of Ti-Nb microalloyed high-speed guardrail steel under continuous cooling

Li Yanqi; Gan Xiaolong; Liu Yajun; Wang Cheng; Zhang Zhuoyu

doi:10.7513/j.issn.1004-7638.2023.02.022

Volume 44 Issue 2

Apr. 2023

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Li Yanqi, Gan Xiaolong, Liu Yajun, Wang Cheng, Zhang Zhuoyu. Study on microstructure transformation behavior of Ti-Nb microalloyed high-speed guardrail steel under continuous cooling[J]. IRON STEEL VANADIUM TITANIUM, 2023, 44(2): 153-159. doi: 10.7513/j.issn.1004-7638.2023.02.022

Citation:

Li Yanqi, Gan Xiaolong, Liu Yajun, Wang Cheng, Zhang Zhuoyu. Study on microstructure transformation behavior of Ti-Nb microalloyed high-speed guardrail steel under continuous cooling[J]. IRON STEEL VANADIUM TITANIUM, 2023, 44(2): 153-159. doi: 10.7513/j.issn.1004-7638.2023.02.022

Citation:

Li Yanqi, Gan Xiaolong, Liu Yajun, Wang Cheng, Zhang Zhuoyu. Study on microstructure transformation behavior of Ti-Nb microalloyed high-speed guardrail steel under continuous cooling[J]. IRON STEEL VANADIUM TITANIUM, 2023, 44(2): 153-159. doi: 10.7513/j.issn.1004-7638.2023.02.022

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Study on microstructure transformation behavior of Ti-Nb microalloyed high-speed guardrail steel under continuous cooling

doi: 10.7513/j.issn.1004-7638.2023.02.022

1.
Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China
2.
Wuhan Iron and Steel Company Limited, Wuhan 430080, Hubei, China

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Received Date: 2022-07-01
Publish Date: 2023-04-30

Abstract

Abstract

The thermal simulation testing machine, OM, TEM and other experimental equipment were used to study the continuous cooling transformation behavior of Ti-Nb microalloyed high-speed guardrail steel in the experiment. The results show that when the cooling rate is 0.5 ℃/s, the austenite of the test steel emerges ferrite-pearlite phase transformation. When the cooling rate is greater than 1 ℃/s, the bainite phase transformation begins to occur. At the cooling rate of 10～20 ℃/s, both ferrite-bainite phase transformation and martensite phase transformation come out. While the bainite-martensite phase transformation appears when the cooling rate rises to 30 ℃/s. As the cooling rate increases, the hardness of the test steel also improves. There exists (Ti, Nb) dispersed precipitates in the steel at different cooling rates. In the condition of low cooling rate, the volume fraction of the precipitates in the steel is larger, and the size is smaller, which has a certain precipitation strengthening effect.
- high-speed guardrail steel,
- Ti-Nb microalloying,
- CCT curve,
- hardness

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References(13)

References

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