Coating for lost mould cast steel and manufacture method thereof

Abstract

The invention relates to coating for lost mould cast steel and a manufacture method thereof. In the coating, zirconium aluminium talc powder is adopted to serve as fireproof material; CMC (Carboxy Methylated Cellulose) and bentonite are adopted to serve as a suspending agent; modified white glue is adopted to serve as binder; and proper water is adopted to serve as coating carrier liquid and additive. The method for manufacturing the coating comprises the following steps of: preparing the fireproof material of zirconium aluminium talc powde, organic bentonite and little water into paste type coating; pouring in a ball mill; adding proper water to ball-mill for 7-8 h; adding the prepared CMC and the modified white glue to ball-mill for 1 h; preparing into glue type aqueous solution; pouring the coating or pressurizing the coating in a coating barrel through compression air; sufficiently stirring; and adding proper additive. The manufacture cost of the coating is low. The process is simple. A coat can be peeled easily. A cast piece has a few sand cleaning processes. The method disclosed by the invention is applicable for producing lost mould casts of carbon steel and alloy steel.

Description

technical field [0001] The invention relates to a coating and a manufacturing method thereof, in particular to a coating for lost foam cast steel and a manufacturing method thereof. Background technique [0002] The lost foam casting technology is to bond and combine foamed plastic models similar in size and shape to the castings to form a model cluster. After brushing with a refractory coating and drying, it is buried in dry quartz sand for vibration molding, and liquid metal is poured under negative pressure conditions. , the method of vaporizing the model and occupying the position of the model, solidifying and cooling to form the required casting. The lost foam coating plays a very important role in the lost foam casting process, and is an indispensable auxiliary material for the lost foam casting to obtain smooth and high-quality castings. Lost foam cast steel coatings are generally composed of several components such as refractory materials, suspending agents, binders...

AI Technical Summary

Problems solved by technology

[0008] Disadvantages in the prior art Zircon powder coatings are widely used in lost foam cast steel, but zircon powder will decompose SiO2 at high temperature, and SiO2 will react with FeO to form a low-melting point, low-viscosity compound FeO·SiO2, which is easy to cause Chemical sand sticking to castings leads to an increase in casting rejection rate; on the other hand, zircon powder coatings have the problem of poor coating suspension stability to varying degrees, that is, the coating at the bottom of the container is particularly easy to harden, and it is difficult to disperse into a uniform slurry , in use, it not only affects the gasification and gas migration of the pattern, but also affects the surface quality, precision and internal quality of the casting; in addition, zircon powder has better wettability with molten steel at high temperature, which is easy to cause sand sticking in cast steel

At present, the purity of domestic zircon powder is not high, the price is high, and it has a little radioactivity

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