Anti-crack sand mold coating

Abstract

The invention discloses an anti-crack sand mold coating. The anti-crack sand mold coating is prepared by mixing the following components in percentage by weight: 20%-25% of graphite powder, 5%-10% of water glass and the balance of water. The graphite powder is used as a refractory material; the water glass is used as a binder and a penetrant; the water is used as a carrier and a main component and is capable of improving permeability of a coating in a casting surface; the graphite powder has high temperature resistance and lubricating performance, so that the surface roughness value of a casting can be decreased, and the defect that the casting is adhered with sand can be prevented or reduced; the water glass has good permeability and high temperature resistance, so that the permeability and the high-temperature strength of the coating can be improved, and the coating does not easily fall from the surface of a sand mold and crack; besides, the anti-crack sand mold coating is easily prepared, is low in cost and can be popularized and applied.

Description

technical field [0001] The invention relates to a sand mold coating, in particular to an anti-crack sand mold coating. Background technique [0002] The casting auxiliary materials that cover the surface of the cavity and sand to improve their surface refractoriness, chemical stability, resistance to liquid metal erosion, anti-sticking sand and anti-sticking properties are collectively called mold coatings, generally including refractory fillers, Binder, suspending agent, carrier liquid and various additives are five basic components. Among them, the casting coating used to improve the sand (core) surface's anti-sticking sand and metal liquid erosion resistance is called sand coating. Coating, its functions are: reduce the surface roughness value of castings; prevent or reduce the defects of sand sticking in castings; prevent or reduce sand holes and sand inclusion defects in castings; prevent or slow down the adverse effects of some resin sand pyrolysis products on castings...

AI Technical Summary

Problems solved by technology

[0003] There are many kinds of sand coatings, which can be roughly divided into two categories: water-based coatings and alcohol-based coatings. The invention patent application of application publication number CN 103658509 A discloses a high-suspension sand coating, which includes the following components in parts by weight: water (100 parts); phosphorus flake graphite powder (20-40 parts); amorphous graphite powder (60-80 parts); sodium carboxymethylcellulose (0.3-0.6 parts); bentonite (4-5.5 parts); soda ( 0.36 part); Alkylphenol polyoxyethylene ether (0.3 part); Tween 80 (0.05 part), after the sand mold coating of this invention is coated on the sand mold surface of ordinary castings, the sand mold strength can be improved, corrosion resistance, high temperature resistance, Refractory, etc., can greatly improve the performance of the sand mold. However, under the pure low-pressure process conditions, for the large plane of the thick casting, the ordinary sand mold coating will crack under high temperature and heat.

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