WO2014163522A1

WO2014163522A1 - Vertical vacuum-type centrifugal casting apparatus and gate for said apparatus (variants)

Info

Publication number: WO2014163522A1
Application number: PCT/RU2013/000276
Authority: WO
Inventors: Александр Дмитриевич РУДЕНКО
Original assignee: Rudenko Aleksandr Dmitrievich
Priority date: 2013-04-02
Filing date: 2013-04-02
Publication date: 2014-10-09
Also published as: RU136374U1

Abstract

The invention relates to foundry work. A vertical vacuum-type centrifugal casting apparatus comprises a driving support disc to which a body is attached, in a cavity in which a cylindrically shaped flask with perforated openings in the lateral wall is arranged, wherein the body cavity is connected to an evacuation system. The body is equipped with a cover with an outlet valve and with a melt-pouring orifice, the internal sides of the body and of the cover are provided with a multi-layered, thermally insulating coating, and a gate is arranged along the vertical axis of the flask. The apparatus is equipped with a cooling system with guides for air ducts of a receiver and with a forced-cooling blower, and a shell with vertically mounted guides for the flask is arranged in the body cavity directly along the multi-layered, thermally insulating coating on the internal perimeter, said guides serving at the same time as forced-cooling blades; the cavity between the shell and the flask is connected to the cooling system, and the gate is mounted in the flask cavity along the vertical axis thereof, the main casting channel of said gate being formed with at least one channel and in a conical manner, narrowing in the direction from the pouring orifice to the outlet opening.

Description

Vertical centrifugal-vacuum foundry plant and gate for this installation (options)

The present invention relates to foundry and relates to the design of a vertical centrifugal vacuum foundry. The installation is completely based on investment casting technology, with some technical additions, and is intended to improve and possibly predict and expand the casting range of multilayer, composite materials. In particular, an installation is considered that provides high productivity, economy, prediction of the casting process, and work in program control.

State of the art

Increasingly, the requirements for casting have recently accelerated the development of precision casting technology. Initially, the main attention was paid to the production of castings from alloys, which are impossible or difficult to obtain by cutting. Then this method spread to castings of complex configuration, which are usually obtained by machining. Thanks to the benefits of evacuation, the use of vacuum melting has become commonplace in precision casting technology. At first, this method was used in the production of precious metals. Centrifugal casting is used to obtain the finest details. The use of vacuum avoids the oxidation of alloying additives, and, consequently, to obtain an excellent cast surface, which in turn greatly facilitates the process of polishing jewelry.

WO 2011110137, B22D13 / 00, B22D19 / 06, B22D19 / 16, publ. 11/15/2011 1, a method for the production of bimetallic and multilayer castings by gravity or centrifugal casting is described, in which at least two different materials are gradually introduced into the mold. Before casting the second material (metal), the flame is fed into the mold, in which all oxygen is completely burned out, and the concentration of possible oxides is intensively reduced on the surface of the layer of previously supplied material.

In GB 362035, B22D13 / 06. publ. 12/03/2931, the design of a centrifugal injection machine is described, in which a support plate is located on a rotating plate, on which a number of closed casting molds are placed, each of which consists of two parts and which are located around the axis of rotation. The apparatus is closed from above by a lid with air-ventilation openings and a central hole, through which metal is fed into the central gate and further into the gate channels. The metal enters through the inlet of the main gate and fills the central part of the channel, due to its inertness, the metal rotates relatively slower than the walls of the injection molds. The rotational speeds at the location of the holes leading to the gate channels and the central part of the gate are different. Metal from various sections of the central gate is supplied to the openings of the gate channels, as a result of which the metal particles are mixed, and the metal under pressure enters the gate forms through radial gate channels. When the channels are opened directly into the molds due to the centrifugal effect, the metal under pressure enters the molds at a high speed and completely fills them with a uniform density of the metal.

In SU 1770055, B22D13 / 10, publ. 10.23.1992, a centrifugal casting device is described, comprising a housing in which a perforated flask is mounted, a bearing support, a rotation drive, the housing is in communication with a vacuum system, and the flask is made with a flange that is placed between the bearing supports mounted on the housing. Accepted as a prototype for the facility - installation.

This installation is difficult to perform and requires special measures to position the flask and gate. For positioning, it is necessary to dismantle the upper part of the housing and fix the flanging of the flask on the support disk. This creates inconvenience, since for each new batch of blanks it is necessary to check the alignment of the position of the support and the gating system relative to the axis of rotation of the support disk. RU 2058849, B22C9 / 08, B22D13 / 04, publ. 04/27/1996, describes a technical solution, the essence of which is the use of deaf non-communicating volumes formed by the lower expanded part of the riser, the expanded part of the riser is made in the form of volumes isolated from each other, the surface which are made in the form of a curve. Eliminates the need to twist the metal being drained into the central riser, reducing hydraulic losses in the melt flow, and the tapered gate runways coupled with the blades provide a filled flow of metal in them.

In SU 1675038, H01B17 / 58, publ. 01/23/2003, a centrifugal casting device with a vertical axis of rotation is described, in which the gating channels are made in the form of a logarithmic spiral, the cross-section of the gating channel is reduced from the axis of rotation, and the cross-sectional area of the metal receiver is equal to the sum of the input sections of the gating channels. Due to this design, it is possible to reduce hydrodynamic losses, to eliminate the possible occurrence of vortices.

In SU 481365, B22D13 / 06, publ. 08/25/1975, a device for centrifugal pouring is disclosed, the main injection channel of which is made in the form of a helical line, the channel direction being combined with the direction of rotation of the rotor disk, and the sprue inlets in the mold cavity are located on the wall of the main sprue channel farthest from the axis rotor disk rotation. Adopted as a prototype for the object - gate.

The disadvantage of this sprue is that it accelerates the flow of molten metal, but does not provide for the conversion of a turbulent metal flow into a laminar one.

Disclosure of invention

The present invention is aimed at achieving a technical result, which consists in increasing the efficiency of operation due to the guaranteed positioning of the flask relative to the axis of rotation of the housing and ensuring the quality of castings due to conversion when filling forms of a turbulent metal flow into a laminar one. The specified technical result is achieved by the fact that a vertical centrifugal-vacuum foundry installation comprising a rotary drive equipped with a rotary drive mounted support disk, on which a housing is mounted, in the cavity of which there is a cylindrical flask with perforated holes in the side wall, while the cavity of the housing is in communication with evacuation system, and the casing is equipped with a cover with an exhaust valve and with a neck for pouring melt, the casing and the lid are equipped on the inside with a multilayer thermal insulation a coating, and the sprue is located along the vertical axis of the flask, equipped with a cooling system with guides of the receiver’s air ducts and a forced cooling blower, a shell with vertically mounted guides for the flask, which simultaneously serve as forced cooling blades, is placed in the cavity of the housing directly along the multilayer heat-insulating coating, the cavity between the shell and the flask is in communication with the cooling system, and in the flask cavity along its vertical a sprue is installed, the main injection channel of which is made at least single-channel and conical, tapering in the direction from the filler neck to the outlet.

The specified technical result is achieved by the fact that in the sprue for a vertical centrifugal-vacuum foundry installation, in which the main injection channel is made in the form of a helical spiral line, the main injection channel is made single-channel and conical, tapering in the direction from the filler neck to the outlet.

The specified technical result is achieved by the fact that in the sprue for a vertical centrifugal-vacuum foundry installation in which the main injection channel is made in the form of a helical line, the main injection channel is made in the form of two channels, each channel is made conical, tapering in the direction from the fill neck to the outlet, while the direction of the spiral of one channel is opposite to the direction of the spiral of another channel.

These features are significant and are interconnected with the formation of a stable set of essential features sufficient to obtain the desired technical result. The present invention is illustrated by a specific example of execution, which, however, is not the only possible, but clearly demonstrates the possibility of achieving the desired technical result. Description of the figures of the drawings

In FIG. 1 is a cross section of a casting centrifugal-vacuum installation with a lid and a flask;

FIG. 2 is a plan view of a casting centrifugal vacuum installation of FIG. 1, with the cover removed;

FIG. 3 is a cross-section of a casting centrifugal-vacuum installation with a cover and without flask;

FIG. 4 is a plan view of the casting centrifugal vacuum apparatus of FIG. 3, with the cover removed and the flask removed;

FIG. 5 is a cross-sectional view of a centrifugal-vacuum foundry with a cover, a flask and a gate;

FIG. 6 - the first embodiment of a spiral-conical gate;

FIG. 7 - the second embodiment of a spiral-conical gate;

FIG. 8 - the third embodiment of a spiral-conical gate;

FIG. 9 - the fourth embodiment of a spiral-conical gate; FIG. 10 · fifth embodiment of a spiral-conical gate.

The best embodiments of the invention

According to the present invention, the construction of an economical and compact centrifugal vacuum casting plant of high productivity is considered. Such an installation consists of: a platform disk, a rotor shell, flasks, a cover, a protective casing, and controls removed from the installation working area. The installation design also includes: engine, vacuum pump, compressor, injection funnel, speed sensors, temperature sensors, disk stop, emergency power reset button, electromagnetic air valves, protective cover and programmer with monitor. The installation is used for the artistic casting of various metals and alloys from aluminum to titanium alloys, in dentistry, mechanical engineering, aviation, etc.

An essential factor for reliable and stable operation of the foundry is the ability to programmatically control the entire casting process with output to a visual processing monitor: a temporary second-by-second display of each phase of the casting process, in relation to the technological requirements of the casting process of a particular metal. In this case, excludes the so-called “Human factor” - allows you to make the casting process technologically predictable.

A vertical centrifugal-vacuum foundry installation (Fig. 1-4) contains a support disk 1 mounted in a bearing support equipped with a rotation drive (made in the form of a massive driven belt drive pulley, a belt drive with an electric motor and an engine control system is not shown). The support disk in the support base is mounted on the sleeve 2 on the bearing bearings 3 with the possibility of rotation. The shaft 4 of the support disk, mounted in the indicated bearing bearings 3, is made with a coaxial hole forming a channel 5, connected on one side with a vacuum system for discharging the cavity of the internal volume of the installation housing (the vacuum system is not shown, it can be implemented as in the prototype SU 1770055). On the other hand, this channel is in communication with the cavity to accommodate form 6 and gate 7.

The housing 8 itself, on the inner surface of the walls of which a multilayer heat-insulating coating 9 is fixed, is mounted on the supporting disk 1 and has the possibility of rotation with the speed of rotation of the supporting disk. The design of the multilayer thermal insulation coating 9 is not considered.

In the body cavity at a distance from the multilayer heat-insulating coating 9 and coaxially with the axis of rotation of the support disk 1, a cylindrical flask 10 is installed with perforated holes 11 in the side wall (the flask is made in the form of a thin-walled cylinder made of heat-resistant material). And in the cavity formed by the multilayer heat-insulating coating 9 and the outer wall of a cylindrical shape flask 10, directly along the multilayer heat-insulating coating 9 along the inner perimeter there is a shell 12 with vertically mounted guides 13 for the flask, which simultaneously serve as forced cooling blades. This cavity between the casing and the flask is in communication with the cooling system with the receiver duct guides and the forced cooling supercharger (this cooling system is not structurally shown). Thus, when the case rotates and when the cooling gas agent is fed into the shell cavity, the vertically arranged guides on which the flask rests (to position it clearly aligned with the axis of rotation of the case) capture portions of the cooling agent and involve this agent in rotation (ensuring the cooling intensification process )

On the bottom of the housing, grooves 14 are made for clearly positioning the flask and eliminating its independent movement around the circumference relative to the shell and the housing. The housing is closed from above by a lid 15 (there are manual mechanical locks 16) with a release valve 17 and with a mouth 18 of the melt. The lid on the inside is also equipped with a multilayer heat-insulating coating 9.

Sprue 7 in this installation is the vertical axis of the flask and coaxial to the axis of rotation of the housing and the support disk (Fig. 5). In this vertical centrifugal-vacuum foundry installation, a gate is used, in which the main injection channel is made in the form of a spiral-helix line (Fig. 6, 9 and 10). Moreover, this main injection channel can be made single-channel and conical, tapering in the direction from the filler neck to the outlet (such a gate can be used for piece or small batches of products). In this sprue, the laval injection channel can be made equal in length to the length of at least one spiral. For a large number of injection molded products, a gate can be used (Figs. 7 and 8), in which the main injection channel is made in the form of two channels, and each channel is made conical, tapering in the direction from the filler neck to the outlet, while the spiral direction of one channel is opposite the direction of the spiral of another channel (Fig. 7 and 8). In such In a complicated gate, each channel is equal in length to the length of at least one spiral.

Spiral-conical gate is used to convert a turbulent metal flow into a laminar one. Provides acceleration of the flow of molten metal (linear acceleration * rotation speed, as well as due to the narrowing of the sprue channel). This increases the pressure of the casting, increases the clarity of the surface of the casting and the density of the casting. Increasing the efficiency of casting is ensured by reducing the weight of the gating system. Such sprues allow the manufacture of polymetallic castings (strictly calculated weight of each metal layer).

Distinctive features of the installation are:

- the platform is made in the form of a massive support disk 1, driven by a drive pulley to reduce the base center of gravity and stabilize vertical stability. The unit is mounted on the desktop 19, has a built-in cooling system, receiver duct guides and a forced cooling supercharger.

- flask cylindrical, with zonal perforation.

- in order to avoid a sharp loss of the temperature regime of the flasks and thermal stabilization of the working area, the walls of the shells and the covers of the flasks have a multilayer heat-insulating profile.

- the flask covers are unified in vertical articulation with the neck of the flasks, have exhaust valves for accelerated cooling (crystallization) of the outer layer of the products.

- along the inner perimeter of the rotor-shell, vertically mounted guides for the flask, which simultaneously serve as forced cooling blades.

- use of an original gate system with a spiral-conical gate.

The new installation is universal for casting products in the thermal range of melts from 400 ° C to 1800 ° C, using various types of mold masses.

The casting process in such an installation includes:

• molding into a flask of products in several tiers (Fig. 5). To prepare the molding mixture, a molding material is used, which is a cristobalite-gypsum mixture. Currently, for example, in the jewelry industry, imported molding materials K-90, "Supercast" and "Satinkast" are mainly used. The molding sand is prepared by adding distilled water to the molding mass and mixing it thoroughly. The estimated amount of molding material and distilled water is 0.32-0.42 l of water per 1 kg of mixture. Then the filled flask is evacuated and compacted on a vibration-vacuum installation to a residual pressure of 0.98-104 ... 1, 96-104 Pa (0.1 - 0.2 kgf / cm ² ), after which the molding mixture hardens,

• the use of a variable profile geometry of the main casting riser (sprue) of the original configuration, which converts the turbulent metal flow into a laminar flow (in accordance with the laws of hydrodynamics), accelerates the passage of the melt, increases the pressure when filling model forms, creates a high density, reduces porosity and enhances the sharpness of the relief .

• The use of flexible casting modes with a variable speed of rotation, the "pulsating" operation of the receiver and forced cooling makes it possible to predict the speed and depth of the initial and subsequent, if necessary, crystallization phases, that is, to control the quality of the casting.

• Between the first and subsequent layers of the poured metal, it is possible to use the “blowing” of the separating / connecting finely dispersed material, which provides the necessary physical and technical properties of the compound of two or more metals (dispersed modifying ligatures, deoxidation.,.)

• Forced cooling provides, if necessary, directional crystallization of the casting metal, as well as a change in the cooling flow rate, in turn, the physicomechanical properties of the casting are improved.

• The originality of the structural configuration of the sprue system gives reason to exclude the mass of the central sprue from the actual, total, metal melt. • A strictly calculated amount of metal is melted and poured, especially during multilayer casting.

• Makes it possible to cast products, blanks, and composite blanks (from several metal compositions) for forging, stamping, rolling.

Table 1 shows the comparative technical, temporary and economic components of two different foundry technologies. For the initial data, a single standard size of the blade of a gas turbine installation of 60x30x90 mm, weighing 400 g with a ceramic rod (Draer) was chosen. 30 units of the product were manufactured, with braces, profits and the entire gating system of the power supply as a whole. The melt temperature is 1700 ° C, the flask calcined for casting is 900 ° C.

Table 1

Together, we get the economic effect, consisting

savings:

• Metal - 62% - 21 Kg.

• Electric power - fourfold - 96KW

• Working hours - five times - 57 hours • Model wax - 95%

Industrial applicability

The present invention is industrially applicable, tested and has shown high profitability and productivity in the manufacture of products to obtain thin-walled castings, including thin-walled and multi-layer (with layers of different metal or different alloys) with a deviation from the specified size of not more than 0.5% and a surface finish of 5— 6 cl.

Claims

Claim

1. A vertical centrifugal-vacuum foundry installation containing a support disk mounted in a bearing support equipped with a rotary drive, on which a housing is fixed, in the cavity of which a cylindrical flask with perforated holes in the side wall is placed, the cavity of the housing communicating with the vacuum system, and the housing equipped with a cover with an exhaust valve and a neck for pouring melt, the body and the cover on the inside are equipped with a multilayer heat-insulating coating, and the gate is located along the vert the flare axis, characterized in that it is equipped with a cooling system with receiver duct guides and forced cooling blower, a shell with vertically mounted guides for the flask, which simultaneously serve as forced cooling blades, is located in the cavity of the housing directly along the multilayer heat-insulating coating, the casing and the flask, the lower edge installed in the grooves on this part of the body, communicated with the cooling system, and in the polo ti flask along its vertical axis mounted gate, the main nozzle passage which is formed at least one channel and tapering in the direction from lends pouring mouth to the outlet.

2. The gate for a vertical centrifugal-vacuum foundry installation, in which the main injection channel is made in the form of a spiral-helix line, characterized in that the main injection channel is made single-channel and conical, tapering in the direction from the filler neck to the outlet.

3. The gate according to claim 2, characterized in that the main injection channel is made equal in length to the length of at least one spiral.

4. The gate for a vertical centrifugal-vacuum foundry installation, in which the main injection channel is made in the form of a helical line, characterized in that the main injection channel is made in the form of two channels, each channel is conical, tapering in the direction from the fill neck to the outlet holes, while the direction of the spiral of one channel is opposite to the direction of the spiral of another channel.

5. The gate according to claim 4, characterized in that each channel is made equal in length to the length of at least one spiral.