Causes of rough surface of aluminum alloy die casting

After the completion of aluminum die casting it is usually to be found that some of the casting surfaces are smooth, but some of the casting surfaces are rough, you may want to know what are the causes? In fact, the surface roughness of aluminum alloy die - casting is caused by many factors.

The rough surface of aluminum alloy die casting is mainly caused by the following reasons:

1. The surface quality of aluminum alloy.

Aluminum alloy has columnar crystal structure network skeleton and is filled with refractory material, additives and water in the middle which will cause pores of different sizes in the surface after dry roasting. The depth of infiltration is related to the crystal diameter, the sound of the average pore diameter and the radius of the surface curvature.

2. Surface quality of the press type and investment mould.

The surface roughness of the melt surface is the most important ring that affects the surface roughness of the aluminum alloy die casting, which is in turn related to the surface quality of the press, the method of the melt molding and the pressing process parameter.

3. Influence of casting process.

The surface roughness of the casting is affected by the temperature of aluminum alloy, the casting temperature of aluminum alloy liquid, the pressure head, and the vacuum during casting. In particular, shape temperature and casting temperature have a great impact. The temperature of the aluminum alloy and the casting temperature of the aluminum alloy is closely related to the surface roughness of the aluminum alloy die casting. With the increase of temperature and casting temperature of aluminum alloy, the filling performance of aluminum alloy is improved, the depth of infiltration into surface pores is increased, and the surface roughness of aluminum alloy die castings is increased.

4. Influence of alloy.

The thermal conductivity is small. After the use of aluminum alloy, the aluminum alloy solution is poured into the mold to cool slowly. The grain size of the aluminum alloy die castings is thick. For this reason, the aluminum alloy should be modified and filled with zirconite, which has good thermal conductivity, so as to improve the cooling rate of aluminum alloy die castings and make the surface grains of aluminum alloy die castings smaller, so as to reduce the surface roughness of aluminum alloy die castings.

The above are several factors that have great impact to the surface roughness of the aluminum alloy die casting, so great attention must be paid during the casting process in order to achieve smooth surface of aluminum die casting parts.