Reduction amount model for dynamic soft reduction in bloom continuous casting of special steels
LI Yu-jun1，LI Liang1，LAN Peng1，ZHANG Jia-quan1，CHEN Lie2，KOU Yu-shan2
（1. School of Metallurgical and Ecological ， University of Science and Technology， Beijing 100083， China 2. Xining Special Steel Co.， Ltd.， Xining 810000， Qinghai， China）
Abstract：Based on overall mass balance in the casting direction， a theoretical model of reduction amount， suitable for any rectangular continuous casting products， was presented. The impact of arbitrary rectangular section， solidification contraction， thermal shrinking， deformation and temperature on reduction amount can well be described by the formula as [Ri＝2373(fSC,i－fSC,i－1)Thηi，] or [Ri＝－2373ΔTC,iTl－TSThηi]. Where[Ri]is the reduction amount，[(fSC,i－fSC,i－1)]is the center solid fraction increment， Th is the thickness of casting product，[ηi]is the reduction efficiency，[ΔTC,i] is the center temperature increment，[TS]and[Tl]are the solidus and liquidus temperature， respectively. A finite difference numerical method of solving heat transfer and solidification was developed to calculate the reduction amount with consideration of different steel grades，section sizes，casting speeds，superheat and specific water flow. It was found that the soft reduction amount under each reduction roll should increase upon approaching the crater end due to the increased final solidification and decreased reduction efficiency. The effect of carbon and alloy contents， bloom width， casting speed， superheat and specific water flow on the effective total reduction amount is rather limited， while the bloom thickness influences the soft reduction amount remarkably. The soft reduction amount increases by 1 mm as the bloom thickness increases by 30 mm.
2018, Vol. 37 
