About the smelting of aluminum die casting

Alloy smelting is a main link in die casting production, especially much more important for aluminum alloy die casting. On one hand we have to ensure that the main component in the standard, and on the other hand to control the standard impurity content. If the requirements of mechanical properties are not met it will cause mass waste.

In order to meet the characteristics of aluminum alloy, the general principle of aluminum diecast smelting are as below:

1. Microoxidized atmosphere, rapid melting and rapid pouring.

2. Correct calculation and weighing of ingredients.

3. Furnace, tools, coating, drying, and preheating.

4. Fuel, furnace material and flux must be dried and preheated, especially the return material, otherwise it will affect the quality of alloy melting, and there will be safety accidents. 

Resistance crucible furnace and oil furnace are commonly used in the smelting furnace of diecast aluminum alloy. In recent years medium frequency induction furnace has also been used.  

Resistance furnace is characterized by easy control of smelting temperature, less burning of elements, less fluctuation in composition, good quality of alloy, but high power consumption and low production efficiency. The production efficiency of oil furnace is high, the alloy oxidation and inhalation are serious, and the alloy quality is poor. The medium frequency induction furnace has high production efficiency, but the electromagnetic stirring is serious, and the quality of the alloy smelting is worse than that of the resistance furnace. 

The metal materials used in diecasting aluminum alloy are usually melted by casting directly into the furnace with precast alloy ingot. When the furnace temperature (700~720 degrees) is reached, the rapid analysis before the furnace is carried out. If the composition fluctuation is found, the element additives can be used to mediate the composition.

When the alloy reaches the specified furnace temperature, it is immediately discharged for refining. 

First, degassing refining is carried out by using air bag method: 0.3% of the weight of the alloy refining agent (powder), with the inert gas of 0.15mpa, is carried out for degassing refining at the bottom of the pouring bag for 10-15s. Then remove the slag with the slagging agent.

At last the qualified clean alloy is put into the holding furnace beside the die casting machine.

The above is a brief introduction to the smelting of aluminum die casting.

For more die casting process, you can read our related article.

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