Annan, Kofi AhomkahSiyasiya, Charles WitnessStumpf, Waldo E.2016-04-202016-04-202015-10Annan, KA, Siyasiya, CW & Stumpf, WE 2015, 'The influence of niobium content on austenite grain growth in microalloyed steels', Journal of the Southern African Institute of Mining and Metallurgy, vol. 115, pp. 973-980.0038-223X (print)2225-6253 (online)10.17159/2411-9717/2015/v115n10a12http://hdl.handle.net/2263/52068The relationship between niobium content and austenite grain growth has been investigated through hot rolling simulation on a Bähr dilatometer. The effect of delay time between passes during rough rolling in Nbmicroalloyed steels with nitrogen contents typical for electric arc furnace (EAF) melting was studied. The results indicate that the grain growth constants n, Q, and A increase with an increase in Nb content. The activation energy for austenite grain growth Q was found to be in the range of 239 to 572 kJ/mol, the exponential constant n ranged from 2.8 to 6.2, and the material and processing condition constant A from 4.24 × 1012 to 4.96 × 1028, for steels with niobium contents ranging from 0.002% Nb to 0.1% Nb. A general constitutive equation for the prediction of austenite grain growth in these Nb-microalloyed steels under rough rolling conditions has been developed. Good agreement between the experimental and the predicted values was achieved with this constitutive equation.en© The Southern African Institute of Mining and MetallurgyConstitutive equationAustenite grain growthMicroalloyingDeformationElectric arc furnace (EAF)Engineering, built environment and information technology articles SDG-07SDG-07: Affordable and clean energyEngineering, built environment and information technology articles SDG-09SDG-09: Industry, innovation and infrastructureEngineering, built environment and information technology articles SDG-12SDG-12: Responsible consumption and productionEngineering, built environment and information technology articles SDG-13SDG-13: Climate actionArticle