Precoated sand for high-strength crack-resistant hot method and preparation method thereof

Abstract

The invention discloses precoated sand for a high-strength crack-resistant hot method, which is characterized by being produced by the following raw materials in parts by weight: 5-7 parts of plastic property phenolic resin, 80-88 parts of silica sand, 8-10 parts of iron sand, 0.5-0.6 part of lignocelluloses, 3-5 parts of saw dust, 1-2 parts of carbon fibers, 3-5 parts of boron nitride, 0.8-1.2 parts of urotropine, 2.5-3 parts of water, 0.28-0.3 part of calcium stearate and 5-7 parts of synergist. According to the invention, one kind of synergist is added on the basis of the traditional formula, and common precoated sand is modified; the precoated sand is manufactured by a special technology, so the mobility, the air permeability, the thermal dissipation and the intensity of the precoated sand are enhanced; the surface is compact and does not easily crack and deform; the iron sand is added, so that the intensity is increased; since the saw dust and the carbon fibers are added, the tenacity is improved; the precoated sand produced by the invention has the advantages that the intensity is high; the crack resistance is good; the curing speed is rapid; and the production requirements can be met.

Description

Technical field [0001] The invention relates to the technical field of molding sand, in particular to a high-strength anti-cracking thermal method coated sand and a preparation method thereof. Background technique [0002] Coated sand refers to molding sand or core sand covered with a solid resin film on the surface of sand grains before modeling. In recent years, the production process of thermally coated sand is widely used, that is, preheat the sand to a certain temperature, add resin to melt it, stir to coat the surface of the sand, and add urotropine aqueous solution and lubricant. Coated sand is obtained by cooling, crushing and screening. Since coated sand has the advantages of high strength, low gas evolution, high dimensional accuracy of production castings, smooth surface, and convenient storage, it has been widely used in recent years. The coated sand in the prior art has defects such as loose core strength, low strength, incomplete core sand solidification, and easy...

AI Technical Summary

Problems solved by technology

The coated sand in the prior art has defects such as loose local strength of the sand core, low strength, incomplete curing of the core sand, and easy cracking.