Mathematical Model of Thin Strip Casting
Hong Zhu, Guowei Liand Brian Thomas
Department of Energy, Armco
The thin strip casting process continuously solidifies 1-4 mm thick steel strip.
Once perfected, this process will offer huge energy and capital cost savings
over conventional casting and rolling processes for producing steel sheet
products. Mathematical models have been developed to predict and understand
fluid flow, heat transfer, and stress generation in this new process.
The results were evaluated in conjunction with measurements on a single-roll
pilot strip caster at Armco. They were used to understand and predict
freeze-up in the nozzle and strip thickness, distortion, and cracks.
A transient heat transfer model (STRIP1D) has been developed to simulate the
single-roll continuous strip-casting process. The model predicts temperature
in the solidifying strip coupled with heat transfer in the rotating wheel,
using an explicit finite difference procedure. The model has been calibrated
using strip thickness data from a test caster at ARMCO Inc. and verified with
a range of other available measurements. The strip/wheel interface contact
resistance and heat transfer was investigated in particular, and an empirical
formula to calculate this heat transfer coefficient as a function of contact
time was obtained. Wheel temperature and final strip thickness are
investigated as a function of casting speed, liquid steel pool depth,
superheat, coatings on the wheel hot surface, strip detachment point,
wheel wall thickness and wheel material.
Schematic of Single-Wheel Thin Strip Casting Process.
To obtain the superheat flux of the fluid flow in the nozzle, the velocity and
temperature distributions in the liquid poll were calculated by solving the
Navier-Stokes equations, k-e turbulence model, and energy balance equation
using the well-known SIMPLE algorithm with up-winding on a 60x40x20 staggered
Superheat tmeperature field: (a) 10 seconds, (b) steady state.
More information can be found in the paper:
Li, G. and B.G. Thomas, "Transient Thermal Model of the Continuous
Single-WheelThin-Strip Casting Process", Metallurgical Transactions B, Vol. 27B(June), 1996, pp.509-525. Click here for a PDF version. (759 KB)