Cast iron evaporative pattern coating and preparation method thereof

Abstract

The invention relates to the technical field of evaporative pattern coatings, and in particular relates to a cast iron evaporative pattern coating and a preparation method thereof. The cast iron evaporative pattern coating comprises the following components in parts by weight: 100 parts of refractory aggregate, 2-4 parts of a suspending agent, 1.2-1.6 parts of an adhesive, 0.4-1 part of a thickening agent, 0.5-1.2 parts of a sintering agent, 0.2-0.6 part of an antioxidant and 0.2-0.5 part of an anti-foaming agent, wherein the thickening agent is one or two of sodium carboxymethyl cellulose and xanthan gum; the sintering agent is sodium tripolyphosphate. The coating is good in coating property, a coated layer is free of flow marks or drain marks and good in thermal property and air permeability and is not infiltrated with a molten metal liquid; a cast piece is smooth in surface and free of sand adhesion defect. The preparation method comprises the following steps: uniformly mixing the powder-like components, pouring water into a stirring bucket, pouring the mixed components into the stirring bucket, and stirring for 30-40 minutes by using a stirring machine, wherein the weight of the water accounts for 80% that of the coating. The coating does not need to be prepared for a second time when be used, thus being convenient to use.

Description

technical field [0001] The invention relates to the technical field of lost foam coatings, in particular to a cast iron lost foam coating and a preparation method thereof. Background technique [0002] Lost foam coating is an indispensable auxiliary material for lost foam casting to obtain high-quality castings with a smooth surface. If there are problems in the performance, preparation and drying of the coating, the quality of the casting will be unstable and the rejection rate will increase. The use performance of coatings for lost foam casting is mainly thermal performance and air permeability. Thermal performance mainly refers to good thermal conductivity and low thermal expansion coefficient, so as to prevent sand sticking and slag inclusion on the surface of castings during pouring, while air permeability directly controls The escaping speed of foam melting and decomposition products determines the flow speed of liquid metal, which in turn determines whether defects su...

AI Technical Summary

Problems solved by technology

[0004] The lost foam coatings of the prior art, on the one hand, have poor thermal performance and gas permeability, and poor high temperature stability, which leads to defects on the surface of castings, poor coating performance, easy to produce flow marks, drop marks, and poor peeling performance , that is, the coating shell is not easy to peel off from the casting surface after pouring; on the other hand, secondary preparation is required when using, that is, some materials are mixed first, and after adding water, other materials need to be added to stir again, which increases the unstable factors in the production process. and longer stirring time