The advantages are: high production efficiency, low cost, good surface quality and high dimensional accuracy. The shortcomings are also obvious: the mold cost is high, the density is not high, the inside is prone to shrinkage and shrinkage, and the internal pore slag holes are many (the aluminum liquid is filled with a large amount of air to form pores and slag holes when injected at high speed), mechanical strength and The elongation is low (this is because the die casting can not be used for T6 heat treatment to increase the strength. The reason why the T6 heat treatment cannot be used is because there are a lot of pores inside, and the elongation is low because the iron content of the die-cast aluminum alloy is too high, and the iron content is higher. The lower the elongation, the poor air tightness, the die castings often need to be vacuum sealing process to block the shrinkage and porosity of the casting. And produce some complex products with internal cavities, such as products such as teapots with small belly.
The gravity casting process adopts a process of slowly pouring molten aluminum into a casting mold and naturally cooling the forming process. The advantages and disadvantages are just opposite to the die casting. The produced product has a complicated structure, the interior is uniform and dense, and the good mold design can be achieved. There is no pore slag inside the aluminum casting, the product can be strengthened by T6 heat treatment, and the finished aluminum product has high specific mechanical strength, good elongation and good air tightness.
Because the internal pores are invisible under the naked eye, we can X-ray the aluminum castings with X-ray machine, and the internal condition of the aluminum alloy castings can be clearly seen under X-rays.