RU2051008C1 - Method of manufacturing special ingots according to removable patterns - Google Patents

Abstract

FIELD: foundry engineering. SUBSTANCE: preliminary manufactured mould is composed of (in mass/per cent) gypsum 40,0-55,56, starch 14,29-22,22, water the rest. Then the following composition (in mass/ per cent) is applied to the mould by method of roughing moulding: semiwater solution of calcium sulfate is of 40,0-40,9, silicon dioxide is of 30,0-40,7, asbestos is of 3,0-10,7, water is the rest. A layer of heat resistant concrete is applied to the surface of the received mould with formation of a shell on it. Then the received block (pattern-mould-shell) is dried in the open air during over 14 days and further it is calcined in a furnace at the temperature of 500-700 C during over 40 minutes. Then the destroyed pattern material is removed and molten metal is poured into the block preliminary heated to the temperature over 50 C. EFFECT: improved quality. 3 tbl

Description

 The invention relates to foundry and can be used in technology, art and architecture.

A known method of art casting a model in piece form [1]
The disadvantages of this method are the presence of seams on the product, low quality reproduction of the fine surface, the inability to use the method for the manufacture of cast stone with a crystalline structure of the product.

 Closest to the claimed is a method for producing metal castings by investment casting, which consists in the fact that the casting model and its sprue system are made of fusible materials (wax, paraffin, stearin, etc.) by pressing or pouring them into lumpy solid forms or in flexible cut in half and “dressed” in hard shells forms. The hardened model is removed from the mold, the grit is cleaned, the gating system is welded and a technological model block is obtained, on the surface of which a gypsum casting mold is made in a certain technological mode (ed. St. N 1261738, class B 22 C 1/18, 1985) from a mixture which contains, by weight.

Sulfate hemihydrate
calcium and anhydrous
calcium sulfate in the ratio (5-9): 1 16.7-41.7 Silica 66.56-37.375 Succinic acid 0.04-0.125 Water Else
This method, as a prototype, complex in technology, difficult to adjust for shrinkage of fusible materials, but acceptable for the manufacture of only metal products. It is impossible to obtain a cast stone product with a crystalline structure in these molds.

 The aim of the invention is to provide a method for producing stone castings with a crystalline structure, simplifying the process, reducing the cost of molded products, expanding the technological capabilities of the method, improving the quality of the visual surface and geometry of the products.

 The goal is achieved by the fact that in the proposed method of manufacturing stone castings with a crystalline structure of artistic castings, the model is made from a mixture of the composition, wt. Calcium bisulfate 40.0-55.56 Starch 14.29 22.22 Water The rest by molding or molding in lumpy solid forms or in flexible (in a hard casing) forms. Sutures are cleaned from the model that has been removed from the mold, installed on a horizontal plane, and a layer of the mixture composition is applied directly to the model by rough molding, wt.

Semi-aquatic calcium sulfate 30.0-40.9 Silicon dioxide 30.0-40.7 Asbestos 3.0-10.7 Water Else
A solution of heat-resistant concrete is applied to the obtained integral block model-form and dried in air for at least 14 days in order for the model-form-casing block to gain the necessary strength (Table 1).

The dried block mounted in the oven chamber, and calcination is conducted at 500-700 ^C for at least 40 minutes (Table 2).

After cooling, the destroyed model material is removed from the calcined block by pouring (or by vacuuming). Before pouring the liquid mass of flame-block-shape casing is heated to a temperature at least 50 ^{° C} (Table 3).

The proposed method for producing stone castings with a crystalline structure differs from analogue and prototype in the following: the model is made from gypsum-starch-water composition, the number of components is taken in the range, wt. gypsum 47.78; starch 18.26; water the rest; on the surface of the model by the method of rough molding, the mold is made of gypsum-sand-asbestos-water, the number of components is taken in the range, wt. gypsum 35.4; sand 35.3; asbestos 6.8, water the rest; on the outer surface of the mold of heat-resistant concrete, the casing is molded, the manufacture of the mold and casing are carried out directly on the surface of the model and the mold without a dividing layer; a single block-model-form-casing is dried in air for at least 14 days; single block-form model shroud calcined at 500-700 ^C for at least 40 minutes; the model destroyed by calcination is removed mechanically; before pouring the liquid melt flame-block-shape casing is heated to a temperature at least 50 ^{° C;} starch in the composition of the model mixture is used as a finely dispersed, hygroscopic, easily combustible and mildly degradable additive; asbestos in the composition of the molding sand is used to create the necessary and sufficient resistance to mechanical and thermal shock of a jet of large cross section of a fiery liquid melt.

 The implementation of the method of producing stone with a crystalline structure of the product will significantly reduce the manufacture of the product, get products large in size and complex in design with an exact repetition of the fine qualities of the surface. In addition, the use of the proposed method will allow introducing a new plastic opportunity of stone into fine art, architecture and technology, connecting stone and metal with a common casting-plastic language, expanding the palette of creative thinking of sculptors, architects and designers, and in industry will allow, using slags of metallurgical production, create conditions for the organization of non-waste production.

Claims (1)

 METHOD FOR MANUFACTURE OF ART CASTINGS BY REMOVABLE MODELS, which includes obtaining a model and molds from it, calcining and casting a mold with metal, characterized in that, in order to simplify the process, expand technological capabilities, improve the quality of the surface of castings and reduce their cost, the model is obtained from the composition wt. Gypsum 40.0-55.56
Starch 14.29-22.22
Water Else
and a composition composition, wt. Semi-aquatic calcium sulfate 30.0-40.9
Silica 30.0-40.7
Asbestos 3.0-10.7
Water Else
then, on the outer surface of the mold, a casing of heat-resistant concrete is formed, the resulting single block is held in air for at least 14 days, followed by calcining in an oven at 500-700 ^o C for at least 40 minutes, and model material destroyed by calcination is removed from the single block by mechanical extraction, and before pouring the molten mass, the block is heated to at least 50 ^o C.

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