Achieving Optimal Continuous Castings
Using the continuous casting process, casters can manufacture ingots, high-pressure tubes, and irregularly-shaped bars of high quality and strength, but the process must be controlled through a delicate balance of pour temperature, mold cooling, and draw rate. FLOW-3D CAST v5.1’s Continuous Casting Workspace includes all the tools needed to simulate and optimize a process design to produce high-quality continuous castings in a cost-efficient manner.
Two primary types of continuous casting processes can be modeled: strand casting and direct chill continuous casting. In strand casting, molten metal is poured from a tundish through a mold which has the shape of the part to be cast. The mold, typically made of graphite, gives the casting its shape and provides some cooling to begin solidifying the melt. Additional cooling is applied to the molten strand by cooling channels placed in the mold.
The image below shows a continuous casting of an aluminum/silicon/magnesium slab. Through careful specification of the flow rate of molten metal through the mold and the cooling applied to the mold, the position of the melt front can be controlled so that the slab is fully solidified when it leaves the mold. Additionally, the grain structure in the slab can be optimized by properly controlling the temperature and solidification profiles. By using simulation to study these parameters, trial and error can be greatly reduced or even eliminated.
Here you can see the evolution of the melt front in the mold.
In direct chill continuous casting, additional cooling is applied directly to the casting. The draw rate on the casting is controlled by allowing the end of the casting to solidify on a starter cap before it is drawn out of the mold.
In this example, a bronze billet is cast using a direct chill continuous casting process. As the billet is drawn from the mold, a cooling spray is applied to the billet. The cooling must be sufficient to maintain a solidified shell on the billet as it leaves the mold. The starter cap is withdrawn at a rate that ensures the cooling rate and feed rate are balanced.
The video below shows a simulation of the direct chill process.
With the tools provided in the Continuous Casting Workspace, process engineers can simulate their designs to ensure maximum casting quality and process efficiency for their continuous castings.
John Ditter
Principal CFD Engineer at Flow Science
