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Surface grinding method and pressure requirements for aluminum castings


Due to loose structure and high porosity, aluminum castings contain a variety of metallic and non-metallic impurities to a certain extent, so it is difficult to guarantee the quality of the anodic oxidation film. In order to obtain the normal quality of the anodic oxidation film, white spots can be avoided in aluminum castings after the anodic oxidation film is dyed.

1.The high-voltage and high-current density impact method is adopted in the production of aluminum castings, and the high-voltage and high-current impact method is adopted in the initial stage of anodic oxidation in the use of aluminum castings, so that the "islands" originally divided by impurities are connected into sheets by high-current impact.

2.At the initial stage of anodic oxidation, the voltage was adjusted to about 30V, and the current density was about 2 ~ 2.5a /dm2. After 3 ~ 5min, the normal anodic oxidation voltage was restored and anodized for 50min.

The slight deficiency of aluminum casting is that the casting may be slightly enlarged if there are screw holes. Therefore, it is necessary to control the anodic oxidation time with high current density and high voltage, and prevent the temperature of the anodic oxidation solution from rising too fast.Cooling measures shall be taken for anodized solution during continuous production.

Aluminum casting surface polishing method, when operating the grinding mill can make down the space of castings, as at the end of the aluminum can have connection is impurity in extent so isolated island bridge, because grinding down at the end of the aluminum sometimes not real filling, bridge, some parts of the filler can by corrosion in the process of alkali corrosion and anodic oxide and fall off.

The shot peening method on the surface of aluminum castings, before the trial of the shot peening method, the author used the method of hammer knocking with round head, its original intention is to make the gap of blocking "island" closed by knocking, to achieve the purpose of connecting into a piece, the result is significant.Considering that the efficiency of shot peening can be greatly improved, the effect of anodic oxidation and dyeing is better than the above two methods.

Generally, if the wall thickness of the cast aluminum can meet the requirements of the shot peening pressure, the higher pressure can be used to improve the quality of the shot peening, the closed pores and gaps can be achieved through the extrusion of the shot, and the surface strength and cleanliness of the cast aluminum can be improved.