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Density and porosity of products produced by die casting and gravity casting processes

2020-01-02 09:51:24

The die casting process uses a high-speed injection of molten aluminum into the die-casting mold and pressure-holding and cooling forming. The advantages are: high production efficiency, low cost, good surface quality, and high dimensional accuracy. The disadvantages are also obvious, the mold cost is high, The density is not high.


The internal structure is prone to shrinkage and loosening, and there are many pores and slag in the internal pores (because the aluminum liquid is mixed with a large amount of air to form pores and slag pores during high-speed injection), and the mechanical strength and elongation are low (this is because the die casting cannot be used as T6 Heat treatment increases strength. The reason why T6 heat treatment cannot be done is because there are a large number of pores in the interior. The low elongation is because the iron content of the die cast aluminum is too high, and the higher the iron content, the lower the elongation). Poor air tightness. Parts often need to be vacuum-sealed to seal the shrinkage and porosity of the casting. And cannot produce some products with complicated inner cavity, such as Manifold coolant, Intake Manifolds, Outlets and Inlets tube, Turbocharger housing ......


                                                                                                 Outlets and Inlets tube by Gravity Casting

 The gravity casting process uses a method of slowly pouring molten aluminum into a casting mold and naturally cooling it. The advantages and disadvantages are just the opposite of die casting. The produced product has a complex structure and an even and dense internal organization. Through good mold design It can make the aluminum castings have no slag holes inside, and the product can be strengthened by T6 heat treatment. The final aluminum castings have high mechanical strength, good elongation and good air tightness.

Micro Stucture  82169-3.bmp

                                                                                          Micro-structure of Aluminum Gravity Casting


Because the internal pores are invisible to the naked eye, we can use an X-ray machine to perform an X-ray inspection of the aluminum casting, and under X-rays, we can clearly see the internal condition of the aluminum alloy casting.