Study Of The Initial Solidification Behavior Of Tin-Lead Alloy Continuous Casting Through Mold Simulator Technology

Abstract:The heat transfer inner the mold among steel, mold flux and mold plays a crucial role in steel continuous casting, which has a close relation with the crystalline structure and surface quality of steel slab, even the success and safety of casting. Most of the researches have indicated that initial solidification of the liquid steel inner the mold and the related heat transfer greatly affect the slab surface quality. And the casting parameters are of the utmost importance for initial solidification. Thus the main goal of this study is to investigate how the casting parameters affect the slab surface quality through studying the inner relationship among the casting parameters, slab surface quality and the heat transfer across the mold.In this study, steel and mold flux were instead of Sn-Pb alloy and silicon oil, an advanced thermal mold simulator with thermocouples was used to simulate the initial solidification and study the heat transfer phenomena with different casting parameters. The heat flux across the mold was calculated by Inverse Heat Conduction Problems (IHCP), according to the measured in-mold temperatures history, which is an effective proof to deduce the initial solidification behavior. Comparing the shell surface with the heat flux at meniscus, the effect of casting parameters on the slab surface quality was investigated.By using this technique, casting parameters of superheat, mold oscillation frequency and stroke were studied. It has been showed that shell surface have a closely relation with the heat flux across the mold, and the thermal behavior of mold surface is more affected by the infiltration of silicon oil and the solidification of melt around the meniscus. Higher superheat or mold oscillation frequency, smaller mold oscillation stroke would help to alleviate the shell surface defects, correspondingly the heat flux fluctuation at meniscus would be smaller. The results obtained in this study can be used to guide the actual production, i.e. adjusting casting parameters to control the initial solidification inner the mold by monitoring the heat transfer at meniscus, to improve the slab surface quality. Moreover, some studies also provide guidance for the design of the mold.