Effect of Na2O and B2O3 on heat transfer behavior of low fluorine mold flux for casting medium carbon steels

Abstract

An investigation was conducted to study the effects of Na2O and B2O3 on heat transfer behavior of low fluorine mold flux for casting medium carbon steels by using Single Hot Thermocouple Technique (SHTT) and an advanced Infrared Emitter Technique (IET) in this paper. Results suggested that crystalline layer thickness, crystalline fraction and interfacial thermal resistance of the mold flux increased with the addition of Na 2O, while they decreased with the increase of B2O 3. Besides, the initial crystallization temperature and steady state heat flux reduced with the addition of Na2O, and they were getting higher with the addition of B2O3. Those results obtained in this research can provide fundamental guidance for designing new type of low fluorine or fluorine free mold fluxes for casting medium carbon steels. © 2013 ISIJ.