Application of Mathematical Modelling to Hot Rolling and Controlled Cooling of Wire Rods and Bars

Abstract

Aset of integrated mathematical mode[s for simulating hot rolling and controlled cooling of wire rods and bars has been developed through extensive laboratory research work and validation against carefu]Iy monitored results from industrial mills. Experimental tests have been carried out on C-Mnand eutectoid steels selected as representative of the various applications of wire rods and bars. Static and dynamic recrystailization of austenite, fraction of transformed austenite, final microstructures and mechanical properties are all calculated by modelling physical phenomenaand using quantitative relationships betweenthe microstructural and kinetic parameters and the process variables, i.e. strain, strain rate, temperature and time. Themodelshave boen applied to predict the microstructure evolution during hot rolling and to investigate the effect of working conditions and recrystallization mechanismson the formation of heterogeneous austenitic microstructures. Theeffects of the cooling patterr, on the temperature profile and the austenite phasetransformation have a]so been studied to prevent: coarse pearlite and martensite formation at the centre of wire rods which have cores enriched in Cand Mn; surface hardening of bars whenwater tube cooling systems are used to control the temperature at the cooling beds. The models provide an important insight into the process that is beneficial to enhancethe quality of long products. © 1992, The Iron and Steel Institute of Japan. All rights reserved.