RU128136U1 - DEVICE FOR MANUFACTURE OF POROUS CASTINGS OF VACUUM IMPREGNATION - Google Patents

Abstract

A device for the manufacture of porous castings by vacuum impregnation, comprising a housing, a liner-bottom and a pore-forming filler, characterized in that the housing is mounted on a stand and provided with a removable cover with a hole for the extension with a gate funnel, and the liner-bottom is equipped with a fitting, the opening of which is for connecting with the vacuum system is blocked by an insert with grooves-vents, while the pore-forming filler located in the housing is made in the form of filling granules of expanded polystyrene clad with a reinforcing shell, and in the upper part of the housing has a hole for the exit of gases generated during thermal decomposition of expanded polystyrene.

Description

The utility model relates to foundry and metallurgical production, in particular, to the production of cast billets (castings, ingots) from metals with a low melting point and low-melting metals and their alloys and can be used for the manufacture of porous products in mechanical engineering, aircraft manufacturing, shipbuilding and other fields industry.

Known shaking chill mold (metal form) for the preparation of castings (castings) by casting from ferrous and non-ferrous metals and alloys, containing a body, bottom, supports, ventilation ducts or vents for the exit of gases, providing a dense structure of castings, without gas sinks and pores (Foundry : textbook for university specialties .-- 2nd ed., revised and supplemented - M .: Mashinostroenie, 1987; p.231-233, fig. 102, a).

The main disadvantage of this chill mold is the impossibility of obtaining porous castings in it, since it is designed to produce dense castings without gas sinks and pores.

Closest to the proposed technical essence is a chill mold for the manufacture of porous castings from aluminum and its alloys by vacuum impregnation of water-soluble fillers, comprising a body, a bottom, a filler and a vacuum wire (Porous cast aluminum // Foundry, 1997. No. 8-9; .56-57, Fig. 1. Obtaining porous castings from aluminum alloys // Foundry, 2010. No. 5; p.14-15, Fig. 5 - prototype).

The disadvantages of this chill mold when using it to obtain porous olives are structural and technological flaws: the inability to strike on the bottom of the chill mold when knocking out (shaking) the casting when it is welded to the body, since the bottom is closed by the wall of the vacuum wire; the use of a soluble filler requires an additional operation — soaking the manufactured castings in water so that pores form in them; heating the filler and chill mold before pouring the melt, requiring additional energy consumption, which generally complicates and increases the cost of the process of obtaining porous castings.

The technical result of the claimed device for producing porous castings is the creation of a new type of device for producing porous castings from metals with a low melting point and low-melting metals and their alloys under vacuum conditions of a simplified design using clad polystyrene foams as a pore-forming filler, which ensures effective and reliable operation in the operation process, obtaining cheap quality products - porous castings from metals: aluminum (Tp. = 660 ° C), magnesium (mp = 651 ° С), zinc (mp = 419 ° С), lead (mp = 327 ° С), tin (mp = 232 ° С and their alloys (terms are “metals with a low melting point "(Al, Mg) and" fusible metals "(Zn, Pb, Sn) and their melting points are taken from the source - Production of castings from non-ferrous metal alloys. Kurdyumov AV, Pikunov MV, Chursin VM , Bibikov E.L .: Textbook for universities. - M .: Metallurgy, 1986. - 416 pp. Pages: 100-101, 159, 308, 319, 315).

The specified technical result is achieved by the fact that in the device for the manufacture of porous castings by vacuum impregnation containing a body, a liner-bottom and a pore-forming filler, the body is mounted on a stand and equipped with a removable cover with a hole for the extension with a gate funnel, and the liner-bottom is equipped with a fitting, the hole of which is blocked by an insert with grooves-vents, for connection with a vacuum system, while the pore-forming filler located in the housing is made in the form of filling granules of expanded polystyrene, plaki reinforced shell, and in the upper part of the housing there is a hole for the exit of gases generated during thermal destruction of polystyrene foam.

The essence of the utility model is illustrated by drawings, where Fig. 1 shows a complete assembly (longitudinal section); figure 2 is a cross section, section I-I in figure 1; figure 3 - polystyrene granules clad with a reinforcing shell (in the context).

A device for the manufacture of porous castings contains a housing 1 mounted on a support 2. On top of the housing 1 has a removable cover 3 with an opening on which the extension 4 is located, made integrally with the gate funnel. In the lower part of the housing 1 there is an insert-bottom 5 with a nozzle 6. To prevent granules from entering the nozzle, the hole in the nozzle 6 is blocked by an insert 7 with grooves-vents 8 (washers). In the cavity of the housing 1 there is a backfill of 9 polystyrene granules clad with a reinforcing shell 10 made in the form of a liquid-glass coating layer with the addition of a surfactant and a dispersed metal powder or powder of a refractory material. Granular polystyrene foam is widely used for casting according to gasification models (LGM). During thermal exposure, thermal degradation occurs (softening - 80-110 ° С, transition to a liquid-mobile state - 164 ° С, formation of volatile substances - 350-420 ° С, intense gas evolution - 561 ° С, burning - at higher temperatures) polystyrene foam (Molding) on polystyrene foam models.Ozerov V.A., Shulyak BC, Plotnikov G.A. - M: Mechanical Engineering, 1969. - 183 p. S.59-62). Metallic powder is added for greater conformity (greater uniformity) with the metal of the resulting casting, powder of refractory material - when this is not required. In the upper part of the housing 1, a hole 11 is made for the exit of gases generated during thermal decomposition of polystyrene foam. Using a rubber vacuum hose 12 (dressed on the nozzle 6), the device will be connected to the vacuum system 13 (shown in figure 1 conditionally).

The operation of the device for producing porous castings is as follows. The assembly is first carried out. To do this, insert a bottom insert 5 with a nozzle 6 into the housing 1 and place it on the stand 2. A hose 12 is put on the nozzle 5. After that, the hole in the nozzle 6 is closed with insert 7 and the polystyrene granules are backfilled 9, clad with reinforcing shells 10 obtained by spraying and sprinkling. The housing 1 is covered with a removable cover 3, on which an extension (extension) 4 with a gate funnel is placed, the joints are sealed. The device is ready for pouring metal (for example, aluminum) melt.

Before pouring, the vacuum system 13 (engine, vacuum pump, vacuum receiver with pressure gauge) is turned on, a vacuum (vacuum) is created in the housing 1 and filling is performed. The melt under the influence of the difference in atmospheric pressure and vacuum in the housing (pressure in the vacuum receiver) enters the housing 1 and fills the gaps (discontinuities) in the backfill of 9 polystyrene granules clad with a sheathing 10 over the entire height of the cavity of the housing 1.

With the fast, transient, metered filling of the cavity of the housing 1 and heating of the backfill 9, the reinforcing shell 10 protects the polystyrene granules from deformation (flattening) and destruction (crushing) of the resulting dynamic and thermal effects (loads). Under the influence of the thermal factor, hardening (sintering) of the liquid-glass coating layer of the shell 10 occurs.

After filling the housing 1 during solidification of the melt as the filling 9 is heated to higher temperatures, thermal degradation (softening, melting, gasification) of polystyrene foam granules in spherical shells 10 occurs (Fig. 3). The resulting thermal degradation products — mainly gases (and coke residue — carbon black) remain in them (partially escape), forming the porous structure of the formed casting.

After cooling, the porous casting is removed (knocked out) from the housing 1, for which the following operations are carried out: the extension 4 is removed and the molding mixture forming the gate funnel is knocked out of it, the sprues together with the removable cover 3 are removed from the casting and the porous casting is shaken out by tipping the housing 1. If the casting is not shaken out (cannot be removed), then lightly strike the liner-bottom 5 and it comes out. A porous casting was obtained (for example, aluminum, or magnesium, or zinc, or from their alloys). The pore sizes in the resulting castings depend on the choice of granule sizes of expanded polystyrene: large granules - large pores, small granules - small pores.

The proposed device for the manufacture of porous castings from metals with a low melting point and low-melting metals and their alloys by vacuum impregnation has a simplified design, technologically, economically, reliably and conveniently in use, allows to obtain high-quality porous castings with a uniform structure (uniform distribution of pores), adjust the size (diameters) of pores due to the size of the polystyrene granules.

The experiments carried out confirmed the operability of the proposed device and the quality of the resulting porous castings.

Claims (1)

A device for the manufacture of porous castings by vacuum impregnation, comprising a housing, a liner-bottom and a pore-forming filler, characterized in that the housing is mounted on a stand and provided with a removable cover with a hole for the extension with a gate funnel, and the liner-bottom is equipped with a fitting, the opening of which is for connecting with the vacuum system is blocked by an insert with grooves-vents, while the pore-forming filler located in the housing is made in the form of filling granules of expanded polystyrene clad with a reinforcing shell, and in the upper part of the housing has a hole for the exit of gases generated during thermal decomposition of expanded polystyrene.

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