A kind of collapsible resin-coated sand

Abstract

The invention relates to resin precoated sand easy to scatter and belongs to the technical field of alloy casting. Raw material components of the precoating sand comprise sodium chloride and modifiedphenolic resin. Taking 100 weight parts of the sodium chloride as the datum, the content of the modified phenolic resin is 2-5 weight parts. The raw material components further comprise 0.2-1 weight part of hardening agent, 0.08-0.3 weight part of calcium stearate, 0.1-0.5 weight part of scattering agent, 0.5-1.5 weight part of coconut oil base glucoside, and 0.1-1 weight part of alkali metal oxide. The precoating sand prepared through the raw material components is high in breaking strength, high in normal-temperature tensile and flexure strength and excellent in scattering performance, and can be removed from a casting easily, precision of the complex aluminum alloy casting is improved, and the resin precoated sand is suitable for large-scale industrialized production.

Description

technical field [0001] The invention relates to an easily collapsible resin-coated sand, which belongs to the technical field of alloy casting. Background technique [0002] With the increase in the demand for aluminum alloy castings, the shape of the castings is becoming more and more complex, and correspondingly higher requirements are put forward for the coated sand for casting. At present, the production of complex aluminum alloy castings generally uses hot box furan resin sand, cold box sand and ordinary coated sand. Although the preparation process of furfur resin sand is mature and simple, its fluidity, sand core surface compactness and collapsibility are poor, resulting in poor surface roughness and precision of castings, making it difficult to produce complex aluminum castings. Although cold box sand has high production efficiency and high dimensional accuracy of the core box, it has low strength, poor storage, high cost, general collapse, and is difficult to adapt...

AI Technical Summary

Problems solved by technology

Although the preparation process of furfur resin sand is mature and simple, its fluidity, sand core surface compactness and collapsibility are poor, resulting in poor surface roughness and precision of castings, making it difficult to produce complex aluminum castings

Although the production efficiency of cold box sand is high and the dimensional accuracy of the core box is high, the strength is low, the storage is poor, the cost is high, the collapse is average, and it is difficult to adapt to complex castings

The strength of ordinary coated sand is relatively high, but the pouring temperature of aluminum alloy is low (about 700°C), and the thermal decomposition temperature of phenolic resin is relatively high, resulting in poor collapse of coated sand

[0003] Chinese invention patent "CN104226888A" discloses a collapsible coated sand and its preparation method. The coated sand is made of the following raw materials in parts by weight: 100 parts of raw sand, 2-4 parts of silane coupling agent, binder 1.5-2.5 parts, 0.1-0.5 parts of curing agent, 1-3 parts of additives and 0.5-1.5 parts of lubricant; the raw sand passes through a 300-mesh sieve and consists of 80% new sand and 20% old sand. The binder is epoxy resin, clay, silicone oil and modified starch, the curing agent is polyethylene polyamine, polyurethane and fatty amine, the additive is boron carbide, ethyl acetate and sugar alcohol, and the lubricant is hard Calcium fatty acid; although the collapsibility of the coated sand prepared by the above raw material formula has been improved, most of the sand will remain in the casting and cannot be removed during subsequent cleaning, which will affect the service performance and life of the casting

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