Gray iron casting production supplier

Gray iron foundry manufacturers, the basic characteristics of molding sand with high density of gray iron castings are: high clay content, low moisture content and low addition of pulverized coal. Therefore, it is necessary to master the following aspects when blending sand.

 

1. Clay content and mud content. The compressive strength of moulding sand with high clay content increases with the increase of specific pressure, and generally reasonable sodium bentonite is controlled at 7% to 10%. The sum of reasonable clay and dead clay in molded sand is equal to the powder content, which is generally controlled at 12% to 16%. Too high or too low powder content will endanger all kinds of performance parameters of moulding sand.

 

2. Water. The moisture content in the production of sand in lost foam casting is the key factor to determine the plastic deformation and adhesion of clay. When the moisture content is too high, it is easy to cause the clay adhesion to deteriorate and the fluidity of the molding sand to decrease, so that the symmetrical relative density of the mold can not be obtained. When the moisture content is too low, the molding sand is not easy to stir, and the molding sand has low compressive strength, high ductility and poor molding ability, which is easy to cause slag inclusion in the casting. In general, the moisture content should be higher than 10% to 20% when the wet compressive strength * is higher than that obtained.

 

3. Original sand grain size. The sand mold with high density is relatively dense in design, and enlarged during pouring, so the original sand particle size is not too centralized, the raw sand particles are round or heptagonal, generally choose three-sieve sand or four-sieve sand.