J. Phys. IV France 120 (2004) 563-570
DOI: 10.1051/jp4:2004120065

Precipitation kinetics of NbC in ferrite of a Nb microalloyed steel

Y.-H. Choi¹, H.-C. Shin², C.-S. Choi³ and Y.-K. Lee<sup>1

1</sup>  Department of Metallurgical Engineering, Yonsei University, Shinchon-dong 134, Seodaemun-ku, Seoul 120-749, Korea
²  POSCO Technical Research Laboratories Sheet Product & Process Research Group, Pohang, PO box 36, 1 Goedong-dong, Nam-gu, Pohang, Gyeongbuk 790-785, Korea
³  Research Institute of Iron and Steel Technology, Yonsei University, Shinchon-dong 134, Seodaemun-ku, Seoul 120-749, Korea

yklee@yonsei.ac.kr
yklee@yonsei.ac.kr

Abstract
The precipitation kinetics of NbC in ferrite matrix of a Nb microalloyed steel was investigated experimentally and numerically. The change in electrical resistivity due to NbC precipitation was measured at different constant temperatures as a function of holding time and was converted to the precipitation kinetics of NbC using a lever rule. The precipitation kinetics was compared with a classical nucleation and growth model and with the hardness. There is a good match among the calculated and measured precipitation kinetics of NbC and the hardness. The numerical and experimental results have been used to construct a precipitation-temperature-time diagram of NbC in ferrite matrix of the Nb microalloyed steel.

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