RU2581539C2 - Method of manufacturing of cavity and hole in blank - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: under the method on the insert a layer of rheological liquid is applied, on the later the axisymmetric pellets of low-melting material are put, then the insert with liquid and pellets is inserted in the magnetic field and held until solidification of the rheological liquid; then the insert with the rheological liquid and pellets is installed in the die-mould and pressed until blank formation, then the magnetic field is removed, the rheological liquid is removed, and blank is sintered at temperature exceeding the melt temperature of the pellets material, the melted pellets are removed, and the insert is removed from the blank.

EFFECT: increased quality of the blanks upon labour intensity decreasing of the blanks manufacturing with cavities or holes.

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Description

The invention relates to mechanical engineering and can be used in the manufacture of extruded metal and dielectric blanks having open cavities and openings.

A known method of manufacturing cooling channels in a metal billet of a turbine blade, including a tab before stamping the core rods, which are etched for 35-50 hours [1], p. 67. The disadvantages of the method include the high complexity of removing the aggregate, violation of the quality of the surface layer, accuracy and channel strength due to the effect of the etchant.

The closest is a method of producing holes in dielectric pressed blanks by electrochemical removal of metal inserts along their length [2], which consists in the fact that in order to expand technological capabilities by obtaining deep holes, the insert is made in the form of a sleeve, inside which an insulated current lead is placed.

The disadvantages of the method are: the high complexity of removing the inserts, limiting the depth of the holes, the possibility of manufacturing parts only from dielectric materials.

The invention is aimed at reducing the complexity of manufacturing pressed metal billets with cavities and holes, improving the quality.

This is achieved by the fact that prior to pressing the blank on the inserts placed in the locations of the cavities and holes, a layer of rheological liquid is applied, onto which axisymmetric granules of fusible material are poured with one layer, the insert with the liquid and granules is placed in a magnetic field and held until the rheological liquid solidifies then install into the mold and press the workpiece, then remove the magnetic field and remove the rheological liquid, then sinter the workpiece at a temperature above the melting point granule material, molten granules are removed and taken out of the insert blank.

The method is illustrated by the following drawings: in FIG. 1 shows an insert in the form of a cavity or hole with a rheological fluid scrapped; in FIG. 2 - insert after applying a layer of granules into the rheological fluid; FIG. 3 is a diagram of the pressing of a workpiece with inserts; FIG. 4 - sintering of the workpiece and the melting of the material of the inserts; FIG. 5 - finished sintered billet.

The method is as follows: perform insert 1 (Fig. 1), having the shape of a cavity or hole with dimensions reduced by twice the size of the granule 2 (Fig. 2). Granules 2 must have an axisymmetric shape, for example a ball, which guarantees the accuracy of cavities or holes in the resulting workpieces. On insert 1, for example, by dipping, apply a layer of rheological fluid 3 (Fig. 1) to the length of insert 1, not less than the depth of the cavity or hole in the workpiece 5 (Fig. 3). An insert 1 with granules 2 and a rheological liquid 3 is placed in a magnetic field 4 (Fig. 2) and held until the rheological liquid 3 solidifies. After that, an insert 1 with granules 2 in a rheological liquid 3 is placed in the position of the cavities or holes in the blank 5 and pressed force "P", determined in each case, in the mold 6 to the formation of the workpiece 5 (Fig. 3). The magnetic field 4 is removed, after which the rheological liquid 3 goes into a liquid state and is removed (Fig. 3) from the space between the insert 1 and the workpiece 5. Removing the liquid 3 is necessary, because when heated, it can ignite or release toxic substances. The pressed billet 5 (Fig. 3) is removed from the mold and sintered (Fig. 4) until the desired material properties of the billet 5 are obtained, the granules 2 melt (Fig. 3) and liquid material 7 is removed, which is removed from the space between insert 1 and blank 5 (Fig. 4) insert 1, after which receive a finished pressed blank 5 (Fig. 5) with a cavity or hole 8.

Example 1 of the use of the method: in a ceramic dielectric pressed billet, it is necessary to obtain a spherical cavity with a diameter of 1 mm to a depth of 3 mm. Use rheological liquid MK2-40, granules of zinc alloy spherical shape with a radius of 0.12 mm. Then the radius of the working part of the insert will be 0.88 mm, the diameter of the cylindrical part 1.76 mm. After dipping the rheological liquid onto the insert, it is sprinkled with one layer of zinc granules and pressed into contact with the insert, after which the insert is placed in the space between the electromagnets and a field strength of 20 · 10 ³ A / m is created, which is for magnetite-based rheological liquid (MK2 -40) provides a magnetic induction of 0.029 T. Under such conditions, the time of "solidification" of a rheological fluid of small depth is 3-4 seconds. The workpiece is pressed from the ceramic mineral powder ЦН 222. At the end of the pressing, the electromagnet is turned off, after which, after 6-7 seconds, the liquid phase of the rheological liquid forms, which merges for subsequent use.

мм. Шероховатость поверхности полости 1,25 мкм, что соответствует требованиям чертежа. Общее время изготовления заготовки не превышало 1 часа, что на порядок ниже, чем при других методах.A blank with an insert is placed in a sintering furnace at 1200 K for 2-5 minutes. During this time, the zinc alloy of granules with a melting point of about 700 K goes into a liquid state and flows from the gap between the insert and the workpiece. After that, the insert is removed from the workpiece, which has a cavity with a radius of 1 _-0.3 mm and depth $${3.2}_{-0.3}^{-0.2}$$

mm The surface roughness of the cavity is 1.25 μm, which corresponds to the requirements of the drawing. The total production time of the workpiece did not exceed 1 hour, which is an order of magnitude lower than with other methods.

с шероховатостью 0,63 мкм, что соответствует требованиям чертежа. Трудоемкость изготовления матрицы снизилась в 28 раз по сравнению с эрозионной прошивкой и доводкой отверстия на доводочном станке.Example 2. In the carbide billet die of a die of a die from a tungsten-cobalt alloy VK20, it is necessary to obtain a through hole with a diameter of 2.8 mm. Using the same granules and rheological fluid, as in example 1, we obtain an insert diameter of 2.56 mm. When pressing, a force of 1.2 · 10 ⁴ Pa is used. Sintering temperature 1700 K, other parameters are similar to those considered in example 1. After removing the insert, a hole with a diameter is obtained $$3_{-0.5}^{-0.2}$$

with a roughness of 0.63 microns, which corresponds to the requirements of the drawing. The complexity of manufacturing the matrix decreased by 28 times compared with erosion firmware and lapping holes on the finishing machine.

Information sources

1. The manufacture of the main parts of aircraft engines / M.I.Evstigneev and others. M .: Engineering. 1972 - 448 p.

2. Copyright certificate 1673329 (USSR) Electrochemical production of small diameter holes in dielectrics (Auth. V.P. Smolentsev, V.T. Trofimov, V.V. Trofimov). Bull. fig. No. 32, 1991.

Claims (1)

A method of manufacturing a pressed billet with a hole, including the use of an insert and a mold, characterized in that a layer of rheological liquid is applied to the insert, onto which axisymmetric granules are made of fusible material, then the insert with liquid and granules is placed in a magnetic field and held until the rheological solidifies liquid, then the insert with rheological liquid and granules is installed in the mold and pressed until the workpiece is formed, after which the magnetic field is removed, the rheological is removed th liquid and sintered preform at a temperature above the melting temperature of the material pellets, the melt granules are removed and the insert is removed from the finished workpiece.

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