In order to improve the purification treatment effect for continuous casting and ensure the stable and reliable melt quality, the molten aluminum adopts a combination of continuous purification treatment inside and outside the furnace.
Purification Treatment for Continuous Casting
The main function of the on-line refining treatment device outside the furnace is to refine crystal grains, strengthen degassing refining, slag removal and alkali metal impurities removal.
Online degassing filter devices include: online degassing unit, electrical control cabinet, gas control cabinet, immersion heater, rotating nozzle, lifting device, CFF filter box, filter plate and heating device, etc.
In the continuous casting and rolling method, liquid aluminum is crystallized in a double-belt caster.
The continuous casting machine has a high cooling rate, which makes it easy to obtain a smaller grain size. The crystal structure of the billet is dense and fine, the dendrite spacing is small, and the solid solubility of alloy elements is large, which improves the product performance to a certain extent. Compared with the casting-rolling method to produce aluminum alloy strips, the continuous casting and rolling method can satisfy the production of alloy varieties with a wider crystallization range.
In terms of production cost, energy saving and consumption reduction, both the casting and rolling method and the continuous casting and rolling method have advantages over the traditional ingot rolling method. However, the export thickness of the cast-rolling method is much thicker than that of the continuous casting and rolling method, and the subsequent cold rolling passes need to be increased; and the cast-rolled slab is mostly as-cast structure, which is not good for subsequent processing.
The continuous casting and rolling method is the same as the casting and rolling method, eliminating the energy consumption of aluminum ingot cutting, milling and aluminum ingot preheating of the traditional aluminum ingot rolling method, and the lower limit of the thickness of the hot strip of continuous casting and rolling is only 1mm, much thinner than the traditional aluminum ingot rolling method, can save most of the cold rolling passes. In the continuous casting and rolling method, hot top accessories such as flow control box, float, flow trough, casting tip and nozzle, etc. which can well control the flow of molten aluminum.