SU1687367A1 - Device for producing reinforced castings - Google Patents

Abstract

The invention relates to foundry, in particular, to the technology for producing gear rims of roller cone tool using centrifugal casting, which work in abrasive media. The purpose of the invention is to improve the quality of reinforced castings. The device contains a mold, an auxiliary cylinder of a cylindrical shape, which is made of aluminum foil with a thickness of 005 1 mm. The auxiliary cup has an outer diameter equal to the inner diameter of the casting hole of the mold 1 or

Description

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The invention relates to foundry, in particular, to the technology of producing gear rims of roller cone tools using centrifugal casting, which work in abrasive media.

The purpose of the invention is to improve the quality of reinforced castings.

The drawing shows a device for obtaining reinforced castings from the front.

The device consists of a mold 1, an auxiliary cup 2, which contains a reinforcing hard alloy 3 In this case, the drawing indicates the working cavity of the form under the upper edge of the teeth 4

The amount of carbide required for reinforcement is placed in the auxiliary cup 2 Auxiliary

the glass is set in the drinking form of the drinking form 1.

When the glass is rotated together with the casting mold, the particles of hard alloy 3, as a result of the action of centrifugal forces, are located in the peripheral zone of the bottom of the Hd 2 stack and in its center a free not formation is formed.

When a liquid metal is poured under the action of a metal jet, the bottom of the glass 2 breaks through, the broken alloy 3 is introduced into the mold, and under the action of centrifugal forces moves into the upper peripheral part of the mold 1. solid alloy 3 after even the prgch G1odit crystallization of a meichlpa with paj-n enm it hard

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smoke alloy 3. As a result, a fairly uniform distribution of hard alloy 3 is achieved across the individual teeth of the casting, as well as along the length of each tooth.

The optimum distance from the bottom of the glass to the upper edge of the mold cavity under the tooth should be in the range of 5-20 mm. Placing the bottom of the glass at a distance of more than 20 mm leads to an increase in the amount of hard metal in the lower part of the teeth. Placing the bottom of the glass at a distance of less than 5 cm to the said edge leads to an increase in the amount of hard metal in the upper part of the teeth.

The thickness of the aluminum foil of 0.05-1.0 mm provides the glass with rigidity when entering from the bottom of the glass into the casting mold of a reinforcing hard metal of various masses. When using a foil with a thickness of less than 0.05 mm, the rigidity of the glass shape is not provided. The use of foil with a thickness of more than 1.0 mm is impractical because the opening of the glass under the action of the generated heat of the liquid metal occurs over a long period of time and this results in crowns that are unevenly reinforced in armor.

Example. Were made crowns rock cutting tools. The weight of the billet casting 15 kg. The amount of hard alloy is 0.4 kg, the grade of hard alloy is cast tungsten carbide, the grit of hard alloy is 0.9-1.6 mm. Brand cast steel 20HNZA. The auxiliary cup was made of aluminum foil 0.08 mm thick, the distance of the bottom of the glass to the working cavity under the upper edge of the teeth was 15 mm. The maximum size of the mold is 250 mm, the diameter of the auxiliary cup is 110 mm, the temperature of the cast steel is 1620 ° C.

The crowns of the rock cutting debris were cut into templates for studying the distribution of hard alloy. During the metallographic studies was

it is established that the grain hard alloy is evenly distributed over the teeth of the crowns. The carbide is evenly distributed along the length of the individual teeth, and along the height of the teeth

the reinforced zone has significant non-uniformity, which does not exceed 1.5-2 mm.

The use of the proposed device for casting reinforcement provides

in comparison with the known simplification of the method of casting reinforcement; uniform distribution of grain carbide on the gear arms of the crowns of the roller tool; uniform distribution of hard metal along the length of the tooth.

Obtaining a uniform distribution of particles of hard alloy in the toothed armament of the rims makes it possible to increase the wear resistance of the reinforced parts (rims) of the rock-destructive tool by approximately 1.2-1.5 times.

Claims (3)

1. A device for producing reinforced castings, mainly gear rims of a roller tool, containing a mold with a vertical axis of rotation, a process glass placed in its filling hole and forming a hard alloy, characterized in that, in order to improve the quality of the reinforced castings, the hard alloy is placed inside the auxiliary cup, and the latter is made of a cylindrical shape of aluminum foil 0.05-1.0 mm thick. 2. The device according to claim 1, in which the bottom of the auxiliary cup is placed 5-20 mm below the level of the upper edge of the working cavity of the mold under the tooth of the instrument. 3. Pop 1 device, characterized in that the auxiliary cup is made with an outer diameter equal to the inside diameter of the filling hole casting mold.