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Vol.45, No.5, 321 ~ 329, 2007
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| Title |
| Steels Materials ; Microstructure and Mechanical Properties of Control Rolled Fe-0.1C-(V,Nb) Steels |
| 조경목 Kyung Mox Cho , 김수영 Su Young Kim , 박인애 In Ae Park , 이영중 Young Jung Lee , 강남현 Nam Hyun Kang |
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| Abstract |
| Following the trend of industrial high strength and toughness structural steel manufacturing, it is evolving and increasing needs of basic research and development efforts. One of the examples is, due to the high cost of vanadium, the replacement of Fe-V steel to Fe-Nb steel. However, there still exist difficulties for commercial production of Fe-Nb steel because of poor impact toughness of this steel comparing with Fe-V steel. In this study, a fundamental investigation was carried out to analyze the microstructure, tensile properties and impact toughness of Fe-Nb steel as a function of the rolling conditions with no post heat treatment. The steel samples were prepared with three different compositions, i.e., Fe-V steel (Fe-0.05V-0.001Nb), Fe-V-Nb steel (Fe-0.014V-0.03Nb), Fe-Nb steel(Fe-0.003V-0.033Nb). The steels were deformed with controlled rolling conditions, namely start rolling temperature(SRT) 1150℃ for the all experiment, but two different finish rolling temperature(FRT); 950℃ and 860℃. Ferrite grain size decreased and thus impact toughness was measured higher at FRT of 860℃ than at FRT 950℃ treated steels. Even though the impact toughness of Fe-Nb steel was quite low due to inhomogeneous distribution of ferrite grain size, Fe-V-Nb steel exhibited impact toughness improved with controlled rolling at FRT 860℃. Application of the controlled rolling process showed one of the possibilities to replace Fe-V steel with Fe-V-Nb and/or Fe-Nb steel. |
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| Key Words |
| controlled rolling, Fe-V-Nb steels, hot deformation simulation, microstructure, tensile properties, impact toughness |
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