[China Aluminum Industry Network] 1, charge processing All the charge must be preheated before entering the furnace to remove the surface moisture and shorten the smelting time. 2. Preparation of crucibles and smelting tools (1) Before using the new cartridge, it should be cleaned and carefully inspected for penetrability defects. Confirm that there are no defects before putting it into use. Preheat it to dark red (500-600 degrees) for more than 2 hours to burn it off. The moisture and combustible materials on the inner wall shall be carefully cleaned when the temperature is below 300 degrees. When the temperature is not lower than 200 degrees, the paint is sprayed on the paint and dried only after drying. (2) Before the use of pressure tools, mixing spoons, ladle and other melting tools must be removed from the residual metal and oxide scales and other dirt, after 200-300 degrees preheat after brushing protective coating, brushing and drying after use. 3, the control of smelting temperature The molten alloy rapidly rises to a higher temperature (about 705 degrees Celsius) and undergoes reasonable agitation to promote the dissolution of all alloying elements. After confirming that all the elements have been dissolved, the alloy is refined and degassed, and the scum is removed to the casting temperature. (Although the temperature of the aluminum solution is difficult to judge with the naked eye, it is necessary to use the temperature meter to control the temperature, the temperature meter should be regularly calibrated and repaired; the thermowell should be cleaned periodically with a metal brush, coated with a protective coating, To ensure the accuracy of temperature measurement results and extend the service life. 4, the smelting time control In order to reduce the oxidation and inhalation of the aluminum solution, the residence time of the aluminum solution in the furnace should be shortened as much as possible, and smelting can be performed rapidly. In order to speed up the smelting process, firstly, a moderately pieced, low melting point return material should be added to form a molten pool at the bottom of the crucible as soon as possible, and then an aluminum ingot can be added, so that it can be slowly immersed in a gradually expanding molten pool to accelerate melting; After the main part is melted, alloy elements with higher melting points and smaller quantities are added, and the temperature is increased and the stirring is performed to accelerate the melting, and then the temperature is lowered and the easily oxidizable alloy elements are pressed. 5, refining treatment Refining temperature: 690-730 degrees The refining agent (fully preheated) is added in an amount of 0.15-0.2% of the weight of the aluminum liquid and pressed into the bell jar The processing time is 5-10 minutes after 3-5 minutes, removing the scum and pouring, the pouring temperature is 700-740 degrees. Pneumatic Butterfly Valve,Double Clip Butterfly Valve,Pneumatic Pvc Butterfly Valve,Pneumatic Control Upvc Butterfly Valve ZHEJIANG KINKO FLUID EQUIPMENT CO.,LTD , https://www.kinkoflow.com
Aluminum alloy melting process and matters needing attention