High strength precoated sand

Abstract

The invention discloses high strength precoated sand, comprising the components of raw sand, a binder, a firming agent, a coupling agent and a lubricant, wherein the dosage of the firming agent is 60-70% of that of the binder; the dosage of the coupling agent is 1-3% of that of the binder; the dosage of the binder is 5-8% of that of the raw sand; the dosage of the lubricant is 1-2% of that of the raw sand; the binder comprises the following ingredients in parts by weight: 60-70 parts of phenolic resin, 10-30 parts of high alumina bauxite powder and 10-20 parts of ferric oxide powder; and the firming agent comprises the following ingredients in parts by weight: 70-80 parts of hexamine, 15-25 parts of potassium nitrate and the balance water. The precoated sand of the invention has higher strength and stronger toughness.

Description

technical field [0001] The invention relates to a coated sand, in particular to a high-strength molded coated sand, which is particularly suitable for the production of castings with complex structures. Background technique [0002] Coated sand refers to the molding sand or core sand that is covered with a solid resin film on the surface of the sand grains before molding. There are two coating processes: cold method and hot method: the cold method dissolves the resin with ethanol, and adds urotropine during the sand mixing process, so that the two are coated on the surface of the sand grains, and the ethanol volatilizes to obtain coated sand; Preheat the sand to a certain temperature, add resin to melt, stir to coat the resin on the surface of the sand, add urotropine aqueous solution and lubricant, cool, crush, and sieve to obtain coated sand. For steel castings and iron castings. Due to the advantages of high strength, low gas generation, high dimensional accuracy of pro...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the defects and problems of insufficient strength and p