SU1033330A1 - Method of producing reinforced moulded stone articles - Google Patents

Abstract

A METHOD FOR OBTAINING REINFORCED STONE CASTING, including the installation of metal reinforcement in the form, heating the reinforcement, filling the mold with melts, solidification, crystallization and annealing of the casting, which is so that, in order to eliminate shrinkage, improve the quality of the casting, and reduce the anomalization of the casting, so as to eliminate shrinkage, improve the quality and reduce nrozh. before the installation, metal fittings H are heated to 600-800 s, and installation: it is carried out in 1-10 minutes after filling the mold with the melt.

Description

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The invention relates to the stone industry, and can be used in the mass and production of simple and shaped stone products.

There is a method of hardening casting - due to the reinforcement of castings. For this, a metal frame made of steel wire is installed in the mold. Sometimes metal fitting parts are used for this purpose. After installation of the reinforcement, the mold is filled with melt. Hardened casting is removed from the mold and subjected to crystallization and annealing in a heat treatment furnace.

However, when using valves with conventional temperatures, stresses occur at the interface between the melt and the cold metal. The size of the stresses increases during the process of solidification of the casting as a result of the significant difference in the coefficients of linear thermal expansion of the metal that is used as reinforcement and casting. This leads to the appearance of numerous microcracks and macrocracks in castings, reducing their strength.

The closest to the proposed technical essence and the achieved result is a method of obtaining reinforced stone casting, according to which, in order to reduce internal stresses in the zone of contact between the melt and the reinforcement mold, the reinforcement is heated, the reinforcement is applied a layer of material of low thermal conductivity, then pouring the melt and slow cooling it. Low material; thermal conductivity applied to the reinforcement may be fiberglass.

Heating the molds and the reinforcement before pouring the melt reduces the tendency to form cracks 2.

However, the simultaneous heating of the mold and the reinforcement to be installed in the mold before it is filled with the melt leads to the deformation and even destruction of the sand molds and to the distortion of the reinforcement. The overdried form loses its strength and, when filled with melt, the molding sand breaks down. A waste on castings, called clogging, is formed. In addition, if shaped, large-sized castings are produced, shrinkage during solidification of the melt is not eliminated. Casting, shrinking shells and porosity is gas-permeable and characterized by reduced strength. When such products are operated in gas-saturated aggregates, leakage of gases and vapors is possible, especially undesirable in the case of, for example, aggressive chlorides or fluorides.

The purpose of this invention is to eliminate shrinkage, improve the quality and reduce the production rejects of products.

This goal is achieved by the fact that according to the method of obtaining reinforced stone casting, the system incorporates a metal fitting into a mold, heats the reinforcement, fills the mold with a melt, hardens, crystallizes and anneals the casting, prior to the installation, the metallic reinforcement is heated to 600-800s and its installation performed 1-10 minutes after filling the mold with the melt.

The essence of the method is that metal reinforcement is introduced into the mold after it is filled with melt. For a more efficient process of removing voids and shrink holes, the reinforcement is not introduced immediately after filling, but after some time. During this time, the melt is cooled, shrink cavities are formed and the mold is formed. The outer crystalline crust of the casting. With the introduction of the reinforcement, a part of the melt, which in the central zones of the casting is still in a liquid state, is displaced and fills up the cavities and voids formed during the holding. This contributes to the compaction of the product, the elimination of shrink holes and voids. The outer crust that has formed with during the holding time interferes with the defocusing of L0VOK, which is possible at the time of insertion of the reinforcement. As a result, the quality of the manufactured products is improved and the production defect is reduced.

In tab. Table 1 presents the parameters of the technological process of reinforcing stone casting, in Table 2 data characterizing stone casting, according to the proposed and known methods.

Table 1.

No shrinkage

The presence of shrink holes, pusSposob way one porosity

The sinks, porosity and voids are absent.

Shrinking

Known in the form of shells and voids

Heating of metal reinforcement contributes to the elimination of shrinkage and cracks in the products. Since the reinforcement is immersed in the melt and not introduced into the cold form, it is sufficient to heat it up to 600-800 ° C, and not to calcine it to higher temperatures, as is required when installing the reinforcement before filling the mold with the melt.

The duration of exposure to the introduction of the reinforcement inside the casting should be 1-10 minutes, depending on the dimensions and cross-section of the products. The delay time is determined by the rate of solidification of the melt, which depends on its rate of melting and cracks on the melt.

At the border, a deforesoprira is reinforced - a stone

Cosmetics is not. Armani rastury.

swimming with

the reinforcement forms a blockage and cracks, which is a marriage.

table 2

Characteristics of the zone of contact of stone cast with fittings

Marriage for shrinkage and blockage is absent. No marriage on the inclusion of m.

There are defects in the inclusion of melted glass cloth in some places, as well as blockages with a moldable mixture.

Ratura or pouring, mass. And. casting configurations. With a shutter speed exceeding 10 minutes, v regardless of the configuration and weight of the casting, as well as the temperature of the melt, lowering the reinforcement inside the casting without destroying it is not possible due to the high viscosity of the solidifying melt and the large crust of the solidified material formed on the casting surface products. Extention less than 1 min does not give a noticeable effect due to the short time of the process of solidification of the melt, during which the shells and cavities do not have time to form.

Example. The method is implemented in the manufacture of covers of thermocouples intended for measuring temperature in titanium-magnesium production units. To do this, a sandy clay mold is prepared on a wooden model on the eternal parade ground. After that, the melt is poured into the mold and held for 5 minutes for the processes of solidification and the formation of shrink holes and cavities. After aging, the casting of the crust and a special device inside the casting (its length is 1300 mm and the outer diameter of 70 mm) are lowered to the metal tube heated to the LIPS, which serves as a reinforcing element of the product, to which the metal processes are welded. When the pipe is lowered, carried out along the central vertical axis of the product, part of the melt is displaced, which is in the center of the casting.

at this point, still in a liquid state. The extruded melt fills the casting, shell and voids formed during solidification, increasing the density, strength and durability of the product under the conditions of an aggressive melt of a mixture of chloride salts. "The casting together with the reinforcing element VES held in a mold until fully solidified, and then demolding, placed in a heat oven for crystallization and annealing.

Manufactured in this way. Products do not have voids and shells. Marriage castings for chips, cracks and shrinkage is reduced by 70-80%. The bonding strength of the reinforcement with the casting material increases 1.5 times. The durability of products increases under operating conditions up to 1.5-2 months instead of 2-3 weeks.

Claims (1)

METHOD FOR PRODUCING REINFORCED STONE CASTING, including the installation of metal reinforcement in a mold, heating the reinforcement, filling the mold with melt, solidification, crystallization and annealing of the casting, so that, in order to eliminate shrinkage, improve quality and reducing production defects of products, prior to installation, the metal reinforcement is heated to 600-800 ° C, and installation: it is carried out 1-10 minutes after filling the form with the melt. o so co so ₍ 'CO!? => I