Research On The Factors Of Thin Strip Thickness And Productivity In Twin-Roll Casting

In the twin roll strip casting process, the molten steel is fed through a delivery system into the special pool formed by the two-counter rotating water-cooled rolls and two side dams. The molten steel is solidified in an extremely short time and exits out from the rolls in the form of strip. Twin-roll thin strip casting has been attracting the attention of steel manufacturers all over the world for their significant energy saving, improved processing efficiency and better mechanical properties of products. Due to the heat transfer and solidification are completed within a narrowly short period of time for the factors influencing the quality of thin strips are very complicated during the strip production process, which makes the process parameters control even more critical and are difficult for improving the strip quality. Instead of the conventional physics experiment, computer simulation is urgently needed to be applied to Twin-roll casting process in order to obtain optimized process parameters for practical application, which has a significant influence on the application of this process in industry.Through numerical simulation method in this article, the commercial software of ANSYS is conducted to study the transport phenomena at the pouring stage of twin roll strip casting. And the key issues occurred in the twin-roll strip casting process are focused. Significant progresses and innovative results have been obtained, which are as follows:(1) According to the characteristic of the Twin-roll thin strip casting, an equation combining the turbulence, heat transfer and solidification was firstly established. The conception of generalized fluid is introduced to integratively describe the flow of molten metal with three states (fluid phase, solid phase and two phase) in the pool. The key problems such as the solid phase ratio, solidification heat, heat transfer coefficient and turbulence viscosity have been conducted with successfully, an unified formula describing turbulence was derived.(2) A two dimensional finite element coupled analysis method considering many complicated factors during twin roll thin strip process was presented. The effects of the pouring temperature, casting speed, exit thickness and roller diameter on the temperature field are gained, and also the effects of those parameters on location trends of Kiss point are analyzed. (3) Based on the regular pattern obtained from the influence of process parameters on the temperature field, the two-dimensional finite element model is establish again for the influence of process parameters on the thickness of exit strip, and the quantitative relationships are listed.(4) Through the study of the influence of process parameters on productivity, we can draw the conclusions that appropriate overheat, big roller diameter, small thickness and big interfacial heat transfer coefficient is conducive to high productivity.