Ingot mold coating and preparing method

Abstract

The invention discloses an ingot mold coating and a preparing method, and belongs to the technical field of non-ferrous metal casting. The ingot mold coating is used for painting of the surface of an inner cavity of an ingot mold during casting of non-ferrous metals such as zinc and aluminum. The ingot mold coating comprises 18%-25% of emery powder, 5%-10% of titanium dioxide, 8%-12% of white mud, 8%-10% of sodium carboxymethylcellulose, 5%-8% of sodium hexametaphosphate, 10%-15% of borax and the balance water. During preparing of the ingot mold coating, emery powder, emery powder, white mud, sodium carboxymethylcellulose and sodium hexametaphosphate are placed in water with the temperature not smaller than 80 DEG C, and finally borax is added. During using, the prepared coating is sprayed to the surface of the inner cavity of the ingot mold at the temperature of 60-80 DEG C. The ingot mold coating is convenient to use and capable of being used online. By means of the coating, the appearances of ingots of non-ferrous metals such as zinc and aluminum are even in luster, and black spot color shading defects do not exist.

Description

technical field [0001] The invention relates to an ingot mold coating and a preparation method thereof, belonging to the technical field of nonferrous metal melting and casting, and is used for coating the inner cavity surface of an ingot mold when nonferrous metals such as zinc and aluminum are cast. Background technique [0002] The current zinc and aluminum ingot molds are mostly made of economical and affordable cast iron materials. During casting production, the ingot molds are fixed on the conveying mechanism of the automatic pouring machine (such as linear automatic pouring machine, disc automatic pouring machine), and the liquid metal After pouring into the ingot mold, the crystallization process is completed through the heat dissipation of the mold wall during the movement of the ingot mold. When the ingot mold reaches the ingot drop position, the metal ingots fall down and enter the stacking process. In the current production practice, the traditional ingot mold ma...

AI Technical Summary

Problems solved by technology

In the current production practice, the traditional ingot mold made of cast iron has the following defects: ① Liquid metals such as zinc and aluminum have good wettability with the ingot mold, which often leads to mold sticking when the metal ingot is demolded, and The appearance of the metal ingot is rough; ②When the liquid metal crystallizes, the temperature at the pouring position at the bottom of the ingot mold is the highest, and the temperature at other positions is lower, resulting in uneven cooling speed at the bottom of the metal ingot, resulting in color quality defects at the bottom of the ingot after solidification; ③Liquid state during pouring The metal has a scouring effect on the surface of the ingot mold, and the high-temperature melt reacts chemically with the wall of the ingot mold during the solidification process, resulting in erosion and corrosion damage to the ingot mold

Due to the casting process of this ingot, the graphite layer is in contact with the liquid metal, which can obtain an aluminum ingot with uniform appearance quality, avoid the color difference defect of the ingot, and the cooling rate can also meet the production cycle requirements of the automatic pouring machine; but the graphite The strength of the inner layer is low, and it is prone to cracks and fractures, causing partial damage to the graphite layer and affecting the stability and continuity of production

[0004] Drawing on the construction principles of metallurgical furnaces, people paint refractory coatings on the surface of zinc ingot molds, which eliminates the color difference and black spots of zinc ingots, and obtains the appearance of zinc ingots with uniform color; however, the poor thermal conductivity of refractory coatings increases the zinc The thermal resistance of the ingot / mold wall interface significantly prolongs the solidification time, resulting in a decrease in production efficiency; in addition, the thermal expansion rate of the refractory coating is quite different from that of cast iron, which is commonly used as an ingot mold material, resulting in partial peeling of the refractory coating, while part The paint adhered to the ingot mold is difficult to remove, which eventually leads to uneven inner cavity of the ingot mold

People also use volatile paint to coat the surface of the ingot mold. Although the ingot mold is protected and the service life of the ingot mold is prolonged, there are burnt objects of the volatile paint on the wall of the ingot mold, and the pouring The process causes environmental pollution due to the burning and volatilization of the paint, so the volatile paint is not suitable for the coating of zinc ingot moulds.