For foundry sand, what are the advantages of ceramic foundry sand over quartz sand in casting? Quartz sand is used in the lost foam industry before, but quartz sand has many shortcomings and is difficult to overcome.Quartz sand has the advantages of wide distribution and low cost; But its shortcoming is also quite obvious: First, the expansion coefficient is big, the casting precision is low; Secondly, sand penetration on the surface of castings is serious and sand removal is difficult. The reason is that quartz can have a variety of isomorphous crystals at different temperatures, and the volume changes greatly; Limited by refractory degree (The refractory degree of quartz sand is between 1400-1700 ℃), local sand penetration of castings is serious, and cleaning is very difficult.The above shortcomings are particularly serious in the production of large steel castings.
The coefficient of thermal expansion is small, the performance can be comparable with zircon sand, with its configuration molding sand, casting will not produce expansion defects. The ceramic foundry sand has good air permeability, and with spherical shape, it has good liquidity, is easy to be filled, and has dense structure, so that the binder can be covered evenly.
Ceramic foundry sand overcomes the disadvantages that quartz sand can not overcome. the disadvantages are: less specification of sand mold, unable to select the sand mold according to the production demand, high expansion coefficient, poor collapsibility, low refractory strength, easy expansion of casting, poor mobility, poor permeability and so on. The coefficient of thermal expansion is small, the performance can be comparable with zircon sand, with its configuration molding sand, casting will not produce expansion defects. Ceramic foundry sand has high refractoriness and good collapsibility; It is a neutral material, suitable for acid-base binder, acid, alkali binder can be used; Ceramic foundry sand recycling performance is good and cost-effective; Ceramic foundry sand can greatly improve the quality of castings, reduce labor intensity, and is a good foundry sand.