KR960011349B1 - Refractories by fusion casting - Google Patents

Abstract

This casting method is an application of lost wax casting used in metal casting. This process consists of making a wax model, casting it with a refractory as burying material of liquid phase to form a mold, heating at 800deg.C during 3hrs, holding at 350deg.C for 30min. and slow cooling until the wax melts and runs out of the mold, and then pouring molten glass into the vacant mold. The buried material in lost wax casting is plaster, on the other hand in this casting, alumina refractory with high melting point over 1600deg.C and good wear resistance is used for casting of molten glass. This burying material comprises alumina refractory powder 100g, mulite 10g, and water 400g. The alumina refractory is selected from sintered alumina refractory, sintered alumina firing insulator, and fused cast refractories.

Description

Shape casting method of melt based on silica

TECHNICAL FIELD This invention relates to the shape casting method of the melt which used the silica as a main material.

In more detail, by developing a special alumina refractory that does not erode into molten glass and using it as a buried material, it is possible to mass-produce a variety of products and crystals by using the shape casting method for the first time.

Usually, when processing crystal or glass, there are manual forms, which depend on the experience and skills of some skilled workers, such as cutting, forming, and polishing the raw stone mass. Alternatively, the material is melted to form the melt. There is a mold casting method that is poured into the mold, but there are many problems such as expensive products and inability to diversify the product when small quantities of various forms are produced due to excessive cost according to mold production.

Moreover, modern society has demanded practicality and new designs for daily products due to the development of industry. Especially, artificial jewelry and glass processed products have a great sense of fashion and the demand for product development and shape diversity is gradually increasing. It is a global trend.

In accordance with this trend, the inventors of the present invention have been researching a method for manufacturing various shapes of products, and the wax wax casting which is commonly used in metal casting is used. After baking it as it is, you get a hint from "How to inject molten metal into a hollow mold."

⊙ The basic process of lost wax casting is as follows.

① Make the designed model out of wax.

② Bury the investment material plaster on the model wax surface and dry it until it hardens.

③ ② is put in the oven firing furnace and the wax melts and flows out. ② The inside of ② creates an empty space as the wax figure.

④ Dissolve the metal in ③ and inject it.

⑤ When the metal cools and hardens, crush the hard investment material and take out the molded metal.

⑥ Gloss the surface of casting (molded metal).

This procedure allows casting to be made from a model made using wax. In the lost wax casting method used for metal processing, since the investment material is gypsum, it is hardly eroded by the melt of metals, but it is eroded by molten glass and cannot be used in the shape casting method of the melt mainly made of silica.

The reason for this is that the temperature of the melt, which is mainly silica, is about 1600 ° C, whereas the temperature at which the components of the investment material are physically decomposed is 786 ° C and the temperature rises above 815 ° C. This is because it discolors. Therefore, in order to cast molten glass, it was necessary to find and manufacture a refractory material that does not erode at all even at 1600 ° C or higher.

After several years of repeated experiments, the inventors have developed a investment agent that is stable to molten glass and that does not erode.

The investment material suitable for casting molten glass should have the physical properties of first, melting point of 1600 ° C or higher, and second, large hardness and high wear resistance. Third, the mechanical strength should be excellent. Fourth, the porosity should be very low, the airtight structure should be possessed. Fifth, the thermal conductivity should be very good. Sixth, the chemical resistance should be large.

The following materials can satisfy the above conditions.

1) Sintered alumina refractories

Sinterkorund, a German product, is obtained by sintering alumina with a purity of 99.3% to 99.8% at 1750 ° C or higher.

2) 자 alumina pre-ignition insulator (點火 栓 碍 子)

3) fused cast refractories

It is a material that melts alumina as a raw material completely in an electric furnace and then casts and solidifies it to have a crystal structure. It is particularly resistant to corrosion among the molten refractories manufactured by Harbison-Carborundum of the United States. Chrome-alumina refractory).

Hereinafter, the present invention will be described in detail.

Manufacture of investment material

1 type of alumina selected from the above semi-fused alumina refractories, semi-fused alumina pre-ignition insulators and monoflox K (a trademark of chrome-alumina refractories having a particularly high resistance to corrosion, among melt-cast refractory manufactured by Harbison-Carborundum) Mortar mortar was prepared by mixing 10 parts by weight of the murite as a liquid adhesive and 400 parts by weight of water to 100 parts by weight of the end of the refractory.

Examples of the present invention are described below, but the present invention is not limited to the examples.

Example 1

After the vandal-shaped model is made of wax, a liquid investment material, in which 100 g of monoplace K powder, 10 g of mulite and 400 g of water is mixed, is coated on the surface of the model wax and dried until it solidifies. After heating at 800 ° C. for 3 hours at room temperature, the temperature was gradually lowered, maintained at 350 ° C. for 30 minutes, and cooled to form an empty space exactly like a wax figure.

After the melt of crystal melted at 1600 ° C. was injected and cooled, the buried material was crushed, the molded casting was taken out, and the surface was polished to prepare a semi-moon shaped quartz casting.

Example 2

A semi-dal shaped quartz casting was prepared in the same manner as in Example 1 except that Sinterkorund powder was used instead of the monoflox K powder used in Example 1.

Example 3

The same product was prepared in the same manner as in Example 1 except that the insulator was used as a fine powder instead of the monoflox K powder as the investment material.

Example 4

In the same manner as in Example 1, but using a common glass melt instead of a crystal melt to obtain a semi-moon-shaped glass product.

Claims (2)

In the lost wax casting method, in order to cast molten glass, a liquid buried material composed of 100 parts by weight of alumina refractory powder and 10 parts by weight of mulite and 400 parts by weight of water was coated on the surface of the model wax, followed by 3 hours at 800 ° C. in a firing furnace. A method of casting a shape of a melt based on silica, characterized in that the molten glass is injected and cast into a mold which is heated, gradually lowered in temperature, maintained at 350 ° C. for 30 minutes and cooled. The trademark of claim 1, wherein the alumina refractories are semi-fused alumina refractory, semi-fused alumina pre-ignition insulators, and monoflox K (chromium-alumina refractories having particularly excellent resistance to corrosion, among melt-cast refractory manufactured by Harbison-Carborundum) The melt-shaped casting method mainly based on silica, characterized in that the selected one.