After batching, smelting, refining and standing, the 6063 aluminum alloy liquid meets the required chemical composition, casting temperature, and metal purity, and completes the preparation stage of the molten aluminum and enters the formal casting stage. The filling stage refers to the process in which molten aluminum is transferred from the stationary furnace into the transfer launder, after online degassing, ceramic foam filter filtration, filling the draft tube and keeping it for a certain period of time.
In the molten aluminum filling stage, the three elements required for casting are: casting speed, equal to zero; casting temperature, due to the heat absorption of laundering, online degassing and ceramic plate filtration in the initial period, the temperature of the molten aluminum is 10℃-20℃ lower than the normal casting temperature; cooling The amount of water (water pressure) is generally 50% to 70% of the normal casting water pressure.
During the molten aluminum filling phase, the following should be noted:
The casting platform, casting launder, filter box, and ceramic foam filter should be fully preheated before casting, generally 15 min-20 min. In order to avoid too much heat absorption at the beginning of casting, too much heat dissipation after the aluminum liquid comes out of the static furnace, resulting in the temperature of the aluminum liquid being too low, and normal casting production cannot be established.
At the beginning, the temperature of the molten aluminum in the standing furnace should be 5℃-10℃ higher than the normal pouring temperature. This can be used to compensate for the heat absorption of the molten aluminum transfer launder, filter box, and filter plate. When the casting enters a stable state, the furnace temperature drops to the temperature state required for normal production.
When there is a box-type online degassing equipment, the temperature of the molten aluminum in the online degassing should be 5℃-10℃ higher than the normal casting temperature, or equal to the normal casting temperature, but in principle, it should not be lower than the normal casting temperature.
Generally, a gate is used to block the entrance of the casting platform. When the aluminum liquid is stored to a certain amount, it is opened quickly to shorten the time for filling the draft tube and make all the draft tubes fill up as much as possible at the same time.
The holding time starts with the one with the slowest filling of the draft tube. Note that in the actual operation, due to the damage or deformation of the hot top cap, the draft tube with the slowest filling is not necessarily the one closest to the molten aluminum inlet. A diversion tube far away, carefully observe during operation.
The holding time generally varies according to the alloy type and the diameter of the ingot. For 6063 aluminum alloy, generally the larger the diameter, the longer the required holding time; the smaller the diameter, the shorter the required holding time.