Advantages of Coated Sand Casting

As a traditional casting process, clay sand casting is restricted by environmental pollution, resource waste, casting quality defects and high production cost, so it has become the choice of reform and reform in the casting industry. Coated sand casting process replaces clay sand casting. Coated sand casting is in the molding and core process, in the hard surface covered with a layer of solid resin film sand and core sand, called coated sand casting. This modeling process has the following advantages:

Less pollution: the work site environment is significantly improved. Since a large amount of pulverized coal is added to the clay sand, the pulverized coal is a combustion-supporting material, so it is mainly used to increase the appearance quality and air permeability of the workpiece. The pulverized coal added to the sand cannot be reused, resulting in a waste of resources. The ash after burning has a great influence on the quality of our working environment. At the same time, the reducing gas and PM2.5 produced in the combustion process cause serious pollution to the atmosphere. Although the molding method based on coated sand has a certain impact on the environment, it uses very little sand, and all the waste sand after use is recycled. Work site clean, no dust pollution.

2. The sand layer is thin and the dosage is small: the production cost is low, the waste is small, and the used molding sand can be recycled and reused. Due to the thin sand coating of this modeling method, the sand coating of 5-10mm is usually designed according to the wall thickness of the moving parts, while the clay sand modeling is usually 30-50cm in small sand coating and 10-20mm in sand coating. Times. Although clay sand can also be recycled twice, the high content of pulverized coal, bentonite and other additional raw materials have been basically exhausted, and the quality of sand is greatly reduced, which affects the appearance quality of the product. After high-temperature roasting, the expansion of the coated sand is greatly reduced, the pickling process in the secondary use is reduced, and the amount of solid resin and curing agent is also greatly reduced, which reduces the production cost.

3. Change the appearance quality of the blank, reduce the cutting allowance, the process yield is high, and the quality is stable. Due to the low hardness of clay sand sand, high preferential, resulting in box expansion, sand expansion, loss of sand, pores, shrinkage and other casting defects are serious, not only resulting in poor product appearance, but more internal casting defects, seriously affecting the service life of the product, high rejection rate. The aggregate in the coated sand molding is pickled or calcined at high temperature, which reduces the expansion of the sand mold after combustion, and has the advantages of high strength and low gas production after curing. The appearance quality, inherent casting defects and product dimensional accuracy are far better than those produced by clay sand molding.

4, improve the internal quality of the product. Due to the fast cooling speed of the coated sand castings, the graphite shape of the castings is greatly improved, the mechanical properties of the product are improved, and the service life of the product is improved. Coated sand molding production products, especially ductile iron, regardless of the degree of spheroidization, matrix organization, hardness, tensile strength, yield strength, etc., are far superior to clay sand molding production products, virtually improve the inherent quality of the product. It increases the service life of the product and indirectly provides a strong guarantee to meet customer needs.