As we all know, fused ceramic sand has been widely used in lost foam casting, self-hardening sand and investment casting because of its special spherical shape, high molding sand strength, high fire resistance temperature and low thermal expansion rate. In the sodium silicate casting process, fused ceramic sand can also play its advantages and achieve higher economic benefits.
Modified ester hardened sodium silicate as adhesive is improved from the traditional casting process of sodium silicate. It can improve the collapsibility of molding sand and core sand and improve the dimensional accuracy of castings. Especially for steel castings and high manganese steel castings, improve the surface quality and fineness.
Modified Ester Hardened Sodium Silicate's main advantages include the following:
The amount of binder added is low, and the hardening speed can be adjusted.
Molding sand has good technological performance and air permeability.
The casting has high quality and dimensional accuracy, good molding sand thermoplastic and low gas evolution, which can prevent casting production cracks and porosity defects.
No irritation, no harmful gas, friendly to operators.
At the same time, the modified ester hardened sodium silicate process has its inevitable disadvantages
For organic resin binder, the collapsibility of molding sand is not significantly improved.
It is difficult to recover the used sand. The wet regeneration produces harmful wastewater, and the dry regeneration has poor recovery effect.
After introducing fused ceramic sand into the modified ester hardened sodium silicate process, it replaced the traditional silica sand molding sand and core sand. Fused ceramic sand 30-50 mesh is usually used to replace silica sand 20-40 mesh. It can effectively improve the collapsibility of molding sand and improve the recycling rate of used sand.
Fused ceramic sand specific advantages are reflected in the following aspects:
The addition of sodium silicate curing agent and resin can be reduced by using fused ceramic sand. For the same amount of binder, the strength of fused ceramic sand is more than 30% higher than that of silica sand.
The particle shape of fused ceramic sand is spherical and its fluidity is good, which can improve the poor collapsibility of sodium silicate casting process.
Fused ceramic sand has high fire resistance temperature, which is greater than 1800℃, and has more obvious advantages in the production of large castings with thick wall and more heat savings.
The defects of sticking sand and iron coated sand can be obviously reduced by using fused ceramic sand.
Fused ceramic sand is a neutral sand, which can meet the production of castings of various materials. Silicon sand is acidic, and it is easy to produce chemical sand sticking when producing alkaline castings such as high manganese steel. Due to its neutral characteristics, fused ceramic sand is not easy to react with the alloy in the molten metal, preventing chemical sand sticking.
Easy for recycling. The hardness of fused ceramic sand is much higher than that of silica sand, and it will not be broken during mechanical regeneration. Thus, the recovery rate of used sand can be improved, the cost can be saved, and the discharge of solid waste can be reduced. Even without wet regeneration, dry regeneration can be recycled for dozens of times.
In order to improve the quality of castings, fused ceramic sand is in point contact with the surface of castings, which can effectively improve the surface quality of castings.