Affect the accuracy of bed casting, life

1, the stomata in the bed inside the casting, the surface or near the surface, there are sizes ranging from smooth holes, the shape of a round, long and irregular, there are single, but also gathered into pieces. The color is white or with a layer of dark, sometimes covered with a layer of oxide. Reduce the amount of gas drawn when smelling. Reduce the sand in the casting process of the amount of gas, to improve the structure of the bed casting, sand and improve the permeability of the core, so that the type of gas can be successfully discharged.

2, loose loose in the bed inside the castings of small and not coherent shrinkage, gathered in one or more, grain thick, there is a small hole between the grain, water pressure test water seepage. Inter-wall connection to minimize the hot section, try to reduce the casting temperature and casting speed.

3, trachoma in the bed inside the casting or surface filled with sand holes. Strict control of sand performance and modeling operations, before the type of attention to clean the cavity.

4, cold cracking in the bed casting on the penetration or not penetrate the cracks (mainly straight), cracking at the metal surface oxidation.

5, cold separation in the bed casting there is an incomplete fusion of the gap or pits, the edge of the border is smooth. Increase pouring temperature and pouring speed. Improve the pouring system. Pouring constantly flow.

6, sticky sand on the surface of the bed casting, all or part of the cover of a layer of metal (or metal oxide) and sand (or paint) mixed with a layer or a layer of burning sand, resulting in bed casting rough surface.

Bed castings are widely used

Can be used for instrumentation, electronics, light industry, standard parts, bearings, auto parts and other parts of the processing. Wear resistance and dimensional stability, a direct impact on the accuracy of bed casting to maintain life.