In the melting and casting production of deformed aluminum alloys, hot top casting is a widely used casting process, which has the following characteristics:
(1) The residence time of the metal in the mold after solidification and forming is short, and the secondary heating phenomenon is basically avoided, so the surface of the ingot is flat and smooth, and the quality is good.
(2) Before the ingot is directly cooled by the cooling water at the lower edge of the mold, the liquid cavity wall formed is very thin. A high crystallization rate can be obtained, so the dendrites are fine.
(3) Equipped with a hot cap above the crystallizer, which opens the distance between the liquid level and the crystallization front, and increases the melt temperature. The gas precipitated during the crystallization of the ingot and the slag carried by it floats conditionally to float to the liquid surface, which is conducive to the improvement of the purity of the ingot.
(4) As the hot cap increases the liquid level, casting can be achieved at the same level, which reduces the secondary pollution of the melt in the pouring system.
(5) Crystallizers can be densely arranged during casting, and the molds for one-time casting are connected with the shunt plate, which improves production efficiency.
The hot top casting process equipment presents the following advantages:
(1) Multiple ingots can be cast at one time. The number of ingots that can be cast per casting is determined by the area of the casting well and the diameter of the ingot. An aluminum processing plant can cast small-sized ingots at a time, which is far more productive than ordinary molds and horizontal casting.
(2) Simple casting operation. At the beginning of casting, open the casting orifice. When the molten aluminum in the launder is 90% high, pull up the launder dam in the distributing launder at the same time, and quickly rake the molten aluminum into the guide pipes. Casting. After casting starts, adjust the water pressure, water volume and increase the liquid level in the launder in time. In this way, dozens of ingots can be cast at a time, and only skilled casters are required during the entire casting process. 3-4 people.
(3) Easy troubleshooting. In the casting process, if a certain ingot is found to be cracked, leaked, etc., just plug the draft tube with tap out cone.
(4) The surface quality of the ingot is good. Practice shows that the preparations before casting are done, especially if the mold is installed and the finisher is lubricated, a better ingot surface can be obtained.