The transfer launder is the channel through which molten aluminum flows from the static furnace to the front box. In order to avoid the heat dissipation of molten aluminum, the transfer launder is required to have good heat preservation. When ensuring the length of the process, the length of the launder should be as short as possible, and it is best to be airtight, so as to avoid excessive drop in melt temperature and avoid secondary pollution of the melt.
In order to facilitate maintenance, the launder is usually made of movable type, the outer shell is welded with steel plate, and the inner lining is made of alumina silicate and asbestos wool. In order to maintain the temperature of the molten aluminum, the launder can be covered with heat-preserving refractory material, or a resistance wire or silicon carbide rod heating device can be installed on the launder. Some factories also use gas flame nozzles to heat to ensure the temperature of the casting launder.
Due to the difference in the relative position of the transfer launder and the front box, the flow of aluminum liquid is also different. There are two typical liquid aluminum supply methods.
Vertical liquid aluminum supply mode, this liquid aluminum supply mode is from top to bottom, and the launder and the front box are at different levels. This method is easy to control the liquid level of the front box, and the liquid level control device is relatively simple, but due to the drop in the process of the aluminum liquid flowing from the launder into the front box, the liquid level drops from the launder to the front box, which is easy to cause the secondary aluminum liquid Slagging by suction.
In the side injection type aluminum liquid supply mode, the launder and the front box are at the same level. This feeding method avoids the drop of molten aluminum. Because the center line of the launder is as high as the center line of the front box, and the center line of the furnace mouth of the standing furnace is lower than the center line of the rolling mill, the oxide film formed on the surface of the molten aluminum acts as a protective layer. The role of. The molten aluminum is supplied in a submerged manner under the cover of the oxide film, which greatly reduces the phenomenon of suction and slagging during the flow of the molten aluminum. However, the liquid level control device in this way is more complicated.