In order to improve the properties of aluminum alloy die castings, the surface roughness of the castings must be treated. This method is to take corresponding measures to deal with the factors that affect the roughness of aluminum alloy die castings. So how to deal with the surface roughness of aluminum alloy die casting?
1. Use fine sand with high fire resistance
2. When using recycled sand, remove too fine sand, burnt clay, ash, metal oxide, scrap metal, iron coated sand and other harmful impurities to improve the quality of recycled sand. Add appropriate amount of new sand regularly
3. Water is a strong oxidant. The moisture content of green sand should be strictly controlled, and appropriate amount of coal powder, asphalt, hydrocarbon and other carbonaceous substances should be added to form reducing atmosphere in the sand. However, the amount of carbonaceous material should be reduced during high pressure modeling to reduce the amount of gas produced.
4. Properly reduce the pouring temperature, pouring speed and pouring height, reduce the height of the upper mold and the height of the gate cup, so as to reduce the metal hydraulic pressure, static pressure and thermal impact on the mold
5. Strengthen the refining of cast steel and other high melting point alloys, purify the molten metal, reduce the oxidation degree and gas content in the alloy liquid, and reduce the forming elements of low melting point phase (such as sulfur and phosphorus). Phosphorus control elements in cast steel and cast iron and bronze (such as manganese and silicon in cast steel and cast iron and lead in bronze) can reduce the surface tension of molten metal and increase the vapor pressure of metal. Molten metal.
6. For large thick wall aluminum alloy die castings, open the packing box as soon as possible to speed up the cooling speed of the castings, so as to prevent solid sand adhesion. 12. Use smooth surface and core box.