RU2374030C2 - Manufacturing method of casting moulds with application of self-curing mixtures with following compaction by filling compound - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to foundry field. Method includes installation on moulding plate of moulding, revetment by self-curing mixture of casting mould, compaction of filling mixtures. On moulding plate it is installed flange of height not less than 2/3 of height of mould and it is located by perimetre around mould at a distance providing cascading of self-curing mixture. Filling of fixtures by filling mixture is implemented under pressure on self-curing facing sand up to its solidification. On surface of impress of mould in those places where it is formed durable superficial crust, it is applied antipenetration wash.

EFFECT: simplification of method of ingots receiving.

3 dwg

Description

Application area

The invention relates to foundry and can be used to obtain the molds of castings using self-hardening mixtures.

State of the art

Known METHOD FOR MAKING CASTINGS FROM BLACK AND NON-FERROUS METALS [patent RU 2048955] and alloys based on them, including the manufacture of molds by pouring a liquid self-hardening mixture into technological equipment, which is pre-installed model, removing it, calcining the mold, pouring mold and metal hardening , characterized in that the calcination of the form is carried out to a temperature not higher than 572 ° C, and the molten metal is poured under pressure by squeezing with crystallization under pressure.

Before pouring a liquid-moving self-hardening mixture, 1-2 layers of refractory material are applied to the model, dried, and then impregnated with water.

The disadvantage of this method is the complexity of the process, the need for its implementation in special production rooms and on special equipment that performs heating to high temperatures.

The closest is a method of manufacturing a casting, comprising sequentially filling the equipment with facing and filling mixtures containing a moisturizing substance, compacting the mixture, freezing the facing layer, extracting the model, assembling the mold and pouring the molten metal into the assembled mold [ed. USSR No. 428843].

The disadvantages of this method of manufacturing castings: the high complexity of obtaining the mold, the insufficient cooling rate of the casting in connection with the use of molding materials with high thermal insulation properties, environmental pollution during knocking molds.

The closest from the prior art is also a method of manufacturing castings [patent RU 2291026] from a metal melt, mainly a light metal melt, including the manufacture of a foundry molding product from a molding material mixed from inert to a metal melt, free-flowing, containing a fraction of synthetic mullite molding base, consisting from particles having a substantially spherical shape and an inorganic binder, the nature of the thermal expansion of the molding base and the binder according to It is interconnected in such a way that the coefficient of thermal expansion of the molten metal is higher than the coefficient of thermal expansion of the foundry molding made from the molding material, the layout of the mold using the foundry molding, pouring the molten metal into the mold and the casting, cooling the casting during the solidification time and cooling, in which the foundry molding product spontaneously breaks into pieces, removal of the foundry molding pieces of jewelry or casting, processing pieces of molding material in molding the granular base. The disadvantage of this method is the large number of stages of implementation and the complexity of the process, high requirements for the shape of the particles of the molding base, which contributes to its high cost. The method requires the manufacture of a foundry molding product from a molding material mixed from inert to a metal melt, free-flowing, containing a fraction of the synthetic mullite of the molding base. Moreover, the method also requires that the nature of the thermal expansion of the molding base and the binder be consistent with each other so that the coefficient of thermal expansion of the metal melt is higher than the coefficient of thermal expansion of the foundry molding made of the molding material. This requirement is feasible in special production conditions with special test equipment. The method requires the assembly of a mold using a foundry molding product, pouring the molten metal into the mold and producing a cast, cooling the cast during the solidification and cooling times.

The purpose of this invention is the implementation of a method that is feasible without the use of sophisticated equipment, special production facilities and exposure to high temperatures.

The technical result of the invention is the simplicity of the method, the possibility of implementation in any production and in the field.

Brief Description of the Drawings

Figure 1 shows the casting form, where 1 is a model, 2 is a model plate, 3 is a self-hardening facing mixture, 4 is a flask, 5 is a filling mixture (composition), 6 is the direction of supply of the filling composition from the sandbox or the direction of sealing of the filling composition manually ;

figure 2 shows the shape of the casting using flanging, where 7 - flanging;

figure 3 shows the imprint of the form, where 8 is the imprint of the model, 9 is the imprint of the flanging.

SUMMARY OF THE INVENTION

The claimed technical result is achieved due to the fact that in the method of manufacturing molds using self-hardening mixtures, which includes sequential filling of equipment with a filling mixture containing a moisturizing substance, sealing the mixture, applying a non-stick coating, the casting model with the flask mounted on the model plate is faced with a self-hardening mixture throughout surface, after which sand filling is carried out with the filling mixture or the filling mixture is densified manually by tamping and / or pneumatic tamping, and / or shaking by presses, and / or pressing, and after the self-hardening mixture has hardened, the model is removed from the mold cavity, and a non-stick coating is applied on the surface of the imprint of the mold in those places where a strong surface crust is formed, then Assembly and casting of the mold with a metal and / or alloy of metals, or other alloys that do not enter into a chemical reaction with a self-hardening mixture. At a distance that ensures the sprinkling of the self-hardening mixture, flanging is performed with a height of at least 2/3 of the model height and having a casting slope.

Filling mixture (5) (see Figure 1), flying out of the sandblasting head at high speed, exerts pressure (in direction 6) on the previously filled model (1) on the self-hardening facing mixture (3), which has not yet hardened, in as a result, the filling mixture is densified and the self-hardening mixture is densified.

The manual seal filling mixture (5) puts pressure (in the direction of 6) on the previously filled model onto the self-hardening mixture (3), which has not yet solidified, as a result, the filling mixture is densified and the self-hardening mixture is densified.

After the self-hardening mixture has hardened, model (1) is removed from the mold cavity, and a strong surface crust forms on the surface of the imprint of the mold. Removing the model from the mold cavity becomes possible due to the fact that the model has molding slopes, and the surface crust formed by the self-hardening mixture has sufficient strength.

The casting model (1) with a flask mounted on a model plate (4) is faced with a self-hardening mixture over the entire surface to obtain an imprint of the surface of the model. Facing can be done, for example, using a conveyor belt, continuous mixer for preparing a self-hardening mixture manually - by pouring.

Sealing with the filling composition by means of a sandblast is carried out for more accurate repetition of the model configuration by the fingerprint and to obtain a strong and evenly compacted surface crust. The sandblasting head is a device throwing packs of the composition onto the surface of the mold. The filling mixture (5) is a moistened working mixture, i.e. after knocking out the casting from the mold, the mixture used for its manufacture goes back to the mold manufacturing process. Compaction of the filling composition manually performs the same function as compaction with a sand gun, only compaction is done manually with rammers (for example, Tamper manual IP 4503) and / or pneumatic rammers (for example, Rammer IP-4503, Tamper TPV-3A-M), and / or shaking presses, which is feasible, for example, using a double-action hydraulic press A300-C1, and / or pressing using known hydraulic presses. The use of all these devices has one purpose - to seal the molding composition, i.e. to obtain a model imprint on the mold.

Applying a non-stick coating on the surface of the mold has the goal of eliminating burns, and obtaining a clean cast surface. The non-stick coating can be applied, for example, with a brush or spray gun. To reduce the flow rate of the self-hardening mixture along the contour of the model (see Figure 2) at a distance that ensures the sprinkling of the self-hardening mixture, flanging (7) with a height of 2/3 of the height of the model and having a casting slope is performed. Flanging means a board made of metal, wood, plastic, and other material, mounted on a model plate, having casting slopes, and located around the model around the model at a distance that allows the self-hardening mixture to spill.

The obtained flanging imprint (9) (see Figure 3) in the mold acts as a well to increase mold compliance during solidification of the metal and reduce the possibility of crack formation during solidification of the casting, as well as to remove gases from the mold cavity.

Claims (1)

A method of manufacturing casting forms using self-hardening mixtures, including installing a flask on a model plate, lining the casting model with a self-hardening mixture, compacting the filling mixture with a sand gun, or by tampering, or pneumatic tamping, or by shaking with presses, or by pressing, or shaking and pressing, characterized in on a submodel plate having casting slopes, install a board with a height of at least 2/3 of the model’s height and place it around the model around the model at a distance providing the self-hardening mixture is sprinkled, equipment is filled with the filling mixture under pressure on the self-hardening facing mixture until it hardens, followed by removal of the model from the mold cavity and applying a non-stick coating on the surface of the mold in the areas where a strong surface crust is formed, then the mold is assembled and filled with metal and / or metal alloy, or other alloys that do not enter into a chemical reaction with a self-hardening mixture.

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