[China Aluminum Industry] Melting is a method of alloying metals. It is the use of heating to change the metal state, so that the matrix metal and alloying components melted into a uniform composition according to the required ratio, and to meet the internal purity, casting temperature and other specific requirements crafting process. The quality of melt has a decisive influence on the processing performance and end-use performance of aluminum materials. If the quality of the melt is congenitally deficient, it will bring potential danger to the use of products. Therefore, smelting dominates the quality of processed products. A key process.
The typical smelting process flow of deformed aluminum alloy is as follows: furnace preparation → burden preparation → batching → loading furnace → melting → adding copper plus zinc → melting after slag → adding magnesium plus helium → stirring → sampling analysis → adjusting composition → stirring → slag → Down-furnace → Refining → Slag slag coverage → Static temperature adjustment → Hydrogen measurement before furnace → Oven → Oven
The above process is usually performed in a smelting furnace and a stationary furnace. Among them, the smelting furnace is responsible for the task of melting and adjusting the components, and the standing furnace is responsible for the task of purifying the melt and keeping warm. The advantage of configuring the equipment in this way is that it can give full play to the production efficiency of the smelting furnace and ensure both the smelting quality and the output. Some factories will complete the above-mentioned process flow in a furnace. At this time, the furnace is charged with the dual task of smelting and standing. It is called smelting and holding furnace. If the furnace is single-bath, the equipment thus configured cannot fully exert the production efficiency of the melting furnace and consumes a lot of energy. In addition, there are individual factories in the country melting in the flame reverberatory furnace, and then use the ladle to transfer the aluminum water into the resistance reverberatory furnace to adjust the composition and temperature, and then in the static furnace to purify the melt and heat preservation process. Such equipment configuration requires three furnaces, and the number of liquid metal injections is too long, and the time for injection is long, so that the melt is heavily contaminated, the melting loss increases, and the pouring ladle needs special equipment for heating. Therefore, from the quality and output Energy consumption is very unfavorable.
At present, the smelting methods used in the aluminum industry in China are roughly divided into batch smelting and semi-continuous smelting. The batch smelting method refers to a smelting method in which one melting cycle is one cycle, from the beginning of charging, melting, to refining, and the end of melting. This method is applicable to finished alloys with high production quality requirements and large batch sizes to ensure the accuracy and uniformity of chemical composition. In general, all special products, ie forgings and die forgings of all alloys; aircraft girder profiles, stage change profiles and small hollow beam profiles used in aviation manufacturing; alloy products used in the atomic energy industry are all smelted in this way. Semi-continuous smelting refers to using the same alloy as a production cycle, with only one-half to one-third of the total amount of melt in the smelter at a time, and then a method of re-melting a new charge that is slightly more than the above. . The advantage of this method is that the charge is immersed in the melt, which not only reduces the burning loss, but also increases the melting speed. At the same time, the temperature fluctuation in the furnace is not great, and the protective effect on the bottom of the furnace is good and the furnace life is improved. The disadvantage is that the composition needs to be effectively controlled, and there is always leftover material in the furnace, which can easily cause local overheating and increase the tendency of the ingot to produce coarse grains. This method is applicable to alloy products that have large smelting batches, low furnace charge grades, and no special requirements on melt quality. In general, pure aluminum and aluminum products, 6063 building materials, and alloy products with recycled charge as the main charge are all smelted using this method.
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