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Production and die casting process of cast aluminum parts


In the process of aluminum casting, aluminum alloy can absorb a large amount of hydrogen during melting and casting, and continuously precipitate out due to the decrease of solubility during cooling.Some data introduce, the more hydrogen that dissolves in aluminium alloy, its solubility increases along with the rise of alloy liquid temperature, decrease along with the drop of temperature, when changing from liquid state into solid state, the solubility of hydrogen in aluminium alloy drops 19 times.Therefore, during the solidification process of aluminum alloy liquid cooling, at a certain moment, the hydrogen content exceeds its solubility and precipitates out in the form of bubbles.Hydrogen bubbles formed by the precipitation of supersaturated hydrogen will be formed as tiny and dispersed pores in the solidification process, namely, gasporosity.The degree of supersaturation reached before the formation of hydrogen bubbles is a function of the number of hydrogen bubbles nucleated, while oxides and other inclusions act as the core of the bubbles.

Under normal production conditions, it is difficult to avoid pinholes, especially in thick sand castings.Pinholes are especially serious in aluminum alloy melting and casting in high relative humidity.This is why we often have people wonder in our production that there are fewer pinhole defects in aluminum alloy castings in dry season than in wet and rainy season.

In the process of die casting, the roughness of the die casting surface will become larger and larger with the service time of the die casting. Meanwhile, the number of large pits and holes on the surface will also become more and more.And the rough surface of the die casting type work and liquid metal in the plane of the contact area is better than the corresponding contact area is larger, thus, liquid aluminum and aluminum casting of the contact area increases, moreover, these holes and pits were coated with paint, greatly increases the liquid aluminum and die-casting directly contact area, which resulted in increased the ratio of Ar/Aa greatly, so that the die casting type welded with aluminum casting tendentiousness.

The hysteresis effect of wetting Angle also exists in the contact system between liquid aluminum and rough die casting workface.There is always paint sprayed on the working surface of the die casting, even where the paint has been washed away.There will still be stains, which can be considered surface contamination.The problem of surface roughness is equivalent to the problem of chemical contamination.For rough solid surfaces, a simple rule of thumb is to introduce a roughness factor, r, which is equal to the ratio of the actual area to the apparent projected area.

At present, the application of leaching technology for aluminum castings in foreign countries is expanding, and advanced industries are all in favor of full leaching treatment for pressure castings.

Aluminum castings are widely used in a wide range of products and industrial categories, including electrical equipment, medical equipment, machine tool accessories and general hardware accessories.

Aluminum castings refer to equipment and devices made of pure aluminum or aluminum alloy by casting.Generally is the use of sand mold or metal mold will be heated to liquid aluminum or aluminum alloy poured into the mold cavity, and the resulting various shapes and sizes of aluminum parts or aluminum alloy parts are usually called aluminum die casting.