Effects of Different Microalloying and Controlled Cooling Technology on Microstructure and Properties of 500MPa High-Strength Rebars

Abstract:

The mechanical properties and microstructures of three different VN, Nb, V-Nb microalloyed rebars were investigated by using tensile testing machine, impact machine, metallographic microscopy, scaning electron microcopy, transmission electron microscopy and X-ray diffraction apparatus. The results showed that the microstructure of V-Nb microalloyed specimen is consisted of ferrite, pearlite and a small amount of fine bainite (6.7wt%), and obvious effect of grain refinement was obtained with more than 10 size grade of ferrite grain, showing optimal comprehensive properties. SEM micrograph of tensile fracture surface for V-Nb microalloyed 500MPa high-strength rebar is dimple and ductile, ductile-brittle transformation temperature is lower than-30°C, which has good plasticity-toughness and impact toughness at low temperature. The results of precipitates have shown that a large number of small and dispersive V(CN) and Nb (CN) precipitates with size of 5~30nm are formed, good effect of precipitation strengthening was achieved in 500MPa high-strength rebars produced by different microalloying and controlled cooling technology.

• Periodical: Applied Mechanics and Materials (Volumes 633-634)
• Pages: 168-175
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.633-634.168
• Online since: September 2014
• Authors: Wei Chen, Jian Chun Cao*, Zhe Shi, Yin Hui Yang, Yu Zhao
• Keywords: 500MPa High-Strength Rebars, Bainite, Controlled Cooling, Ductile-Brittle Transformation Temperature, Microalloying Cooling, Precipitates

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