FR2556994A1 - METHOD AND APPARATUS FOR THE VACUUM DEVELOPMENT AND SHAPING OF A METAL ALLOY - Google Patents

Abstract

THE INVENTION RELATES TO CENTRIFUGAL CASTING. OVEN 1 PREPARES THE METAL IN A VACUUM ENCLOSURE 3. THE LIQUID METAL IS POURED INTO THE CHUTE 10, THEN CENTRIFUGAL IN 7 IN THE VACUUM ENCLOSURE 6. VALVE 5 CAN SEPARATE THE TWO ENCLOSURES 3 AND 6. APPLICATION: ELABORATION SPECIAL ALLOYS FOR CENTRIFUGAL CASTING.

Description

The present invention relates to a method and

  a device for the vacuum elaboration of a lithium alloy

  Metallic ,. and for its shaping by centrifugation.

  The purpose of vacuum metallurgy is to enable the elaboration of alloys, some of whose constituents combine with the temperature of the liquid metal with one or

  the other of the constituents of the air (oxygen, nitrogen, hydro-

  gene, etc ...) or to allow a better development

  alloys that can be made in the air, but whose mechanical, physical and other characteristics are

  improved by elaboration in the absence of atmosphere.

  The vacuum melting and elaboration of

  Metal bonds are a known technique.

  In a conventional arrangement, a melting furnace, generally with electric induction, is placed in a sealed enclosure comprising an access device provided with an equally sealed closure. This furnace is charged with a filler composed of the alloy to be melted or

  metallic elements or parent alloys

  forming the alloy and, after having closed the enclosure and having extracted the gaseous mass which it contains by means of the appropriate pumps until a more or less high vacuum is obtained, to apply the energy necessary to the merger of 1 '

alloy.

  Once the alloy has melted, and its composition

  checked, it is usually transferred from the oven into a

  or in an ingot mold, located in the same enclosure.

  After solidification of the metal, the air is allowed to enter the chamber until the atmospheric pressure is restored. We can then take the ingot or the part thus molded

  Among the methods of shaping

  bonding by fusion, then solidification, centrifugation or centrifugal casting, is known as a process which makes it possible to obtain tubular or annular hollow bodies

  even pieces of shape, particularly healthy and pos-

  seductive good physical and mechanical characteristics.

  It consists of introducing a liquid metal into a generally cylindrical mold, generally rotating

  around its geometric axis so that the alloy,

  dragged by the rotation of the mold, come to press on the walls of the mold, thus producing a hollow body whose solification occurs during the rotation, and this under

  the constant effect of the centrifugal force.

  The axis of rotation of the mold, called

  shell, can be vertical horizontal, or even oblique It is theoretically possible to centrifuge a liquid alloy under vacuum, placing in the same sealed chamber, and after evacuating it, a melting furnace and a centrifuge machine, and transferring the metal

  after melting of the furnace into the centrifuge shell

gation.

  However, this method, which is valid

  laboratory calf, for test pieces, or very

  small series of parts, would be difficult to

industrialization.

  Indeed, more generally in the case of metal centrifugal shells, a preparation

  of the mold must precede the centrifugal casting.

  A classic sequence consists of: 1 - Clean the inner walls of the shell

  2 - Preheat the shell to give it a geogra-

well determined thermal phie

  3 - To peel its internal walls, that is to say their application

  conductive or insulating coating, thick

and of very varied nature.

  This sequence ends shortly

  before casting the metal into the shell.

  The above operations can not be easily done under vacuum, even by automata, during the fusion of the alloy Indeed:

  1. Cleaning produces pulverulent residues which

  would lute the molten alloy 2. Preheating could only be done by induction

  and therefore not easy to modulate.

  3. The poteyage requires an application of the coatings of pa-

  in liquid phase or by spraying, and the fog

  resulting lard, as well as the vapors released, would also pollute the vacuum required for the melting of the metal. It is therefore necessary to carry out these preliminary operations on the shells in a normal atmosphere, and then to put them under vacuum, without disturbing the environment of the melting furnace, so as to make coincide the moment of the centrifugal casting with that of the end of the elaboration of the alloy.

  The present invention aims to avoid

  the aforementioned drawbacks by facilitating the

of the manufacturing process.

  The device according to the invention comprises

  first material for the elaboration, fusion and con-

  control of the centrifugal alloy, as well as a second

  for casting the alloy by centrifugal casting, and it is characterized in that it furthermore comprises: a first sealed enclosure provided with its own means of access, sealing and evacuation, this first enclosure containing the first material; - A second sealed enclosure, provided with its own means of access, sealing and evacuation, the second chamber containing the second material; a sealed conduit connecting the first enclosure to the second

  enclosure, and provided with a watertight shut-off valve

  from the outside to the opening and closing - and transfer means allowing, after opening of

  the sealed duct valve, to dump into the second chamber

  the second chamber, the liquid alloy received from the first material of the first enclosure

  The attached drawing, given as an example

  non-exhaustive list, will help to better understand the

features of the invention.

  Figures: 1 and 2 show a device

  implementing the process according to the invention for

  horizontal centrifugation of tubular metal bodies

res.

  Figures 3 and 4 correspond to two values

  for horizontal centrifugation.

  Figure 5 shows, in plan, a variant o

  the centrifugal shells are mounted on a carrousel

  salt. Figure 6 illustrates another variant to

two opposite speakers.

  Figure 7 shows another variant of which the

enclosure contains several ovens.

  Figure 8 illustrates an additional variant

  shut off for vertical centrifugation.

  The device illustrated in FIGS.

  2 is provided for centrifuging tubular metal parts

around a horizontal axis.

  For this, we use, in the manner

  naked, a melting furnace 1, which is dumped by

  a chute 2 when it is tilted.

  According to the invention, the oven 1 is housed inside a first enclosure 3 in which one can, at will, evacuate. By a sealed conduit 4 provided with a sealed closure valve 5, the first enclosure 3 communicates with the second enclosure 6 in which one

  void, irrespective of the first

  1 The speakers 3 and 6 each have a device for opening and accessing them, allowing them to

  penetrate materials, materials or people

nes, if necessary

  The enclosure 3 is equipped with all the material

  elaboration, fusion and alloy control

to centrifuge.

  In the enclosure 6, there is a device

  mechanics for driving a centrifugal shell

  7. This mechanism, known in itself, may consist of four rollers 8, at least one of which is

  engine, the whole having been designed to be able to function-

under vacuum.

  General reference 9 designates the

  equipment and equipment necessary for cleaning, preheating

  ge, poteyage of a horizontal centrifugal shell.

  In the enclosure 3 is also a

  chute 10 carried by a translational device

  operating in vacuum, so that the pouring tube 11 of the chute can come, after opening the valve 5, protrude into the chamber 6, while its receptacle takes place under the nozzle 2 of the oven 1 (position in full lines, in Figure 1). Translation

  the chute 10 is between this position

  In solid lines and that shown in Figure 1, in broken lines, the operation is as follows: Phase 1 - the enclosure 3 is open The solid materials are loaded into the furnace 1; the enclosure 6 is open; the centrifugal shell is placed on the device 9. Phase 2 - the enclosure 3 is closed - the valve 5 is closed - the chamber 3 is evacuated - the power is applied to the oven 1, to melt the metal - the contraction shell is prepared on the device

  9 (cleaning, preheating, poteyage).

  Phase 3 - just before the material is ready to be poured,

  the centrifugal shell 7 is introduced into the

  encircled 6 and placed on the device intended for

  to be in rotation (rollers 8) - one closes the enclosure 6 - one empties in the enclosure 6 Phase 4 - one opens the valve 5, which makes communicate the two empty enclosures 3 and 6 - one causes the displacement of the trough 10 so that its spout 11 is introduced into the centrifugal shell, while the receptacle formed by its

  funnel is placed under the dump nozzle 2 of the oven.

  This chute It will have been preheated electrically during the melting of the metal in the furnace 1 Phase 5 - the shell 7 is rotated, if the casting must be carried out in a rotating shell (In some cases, in fact, the casting is carried out in a fixed shell which is rotated after filling) - the oven 1 is emptied into the trough 10 which passes the liquid alloy into the shell 7 - the metal alloy which solidifies is thus centrifuged

under vacuum.

  Phase 6 After solidification, two cases can occur: A - or the furnace 1 still contains metal developed and melted under vacuum - the chute 11 is brought back into the enclosure 3 - the valve 5 is closed - the air is left enter the chamber 6 and it is opened - the shell 7 is extracted from the chamber 6 with a suitable device - the centrifuged piece is extracted from the shell 7 - the cycle concerning the shell 7 is recommenced with the same shell 7 until the liquid metal is exhausted in the oven; B - or all of the charge contained in the oven 1 has been transferred to the centrifugation cup 7 - is brought if necessary the chute Il in the chamber 3 - the air is allowed to enter the two chambers 3 and 6 - The shell 7 is extracted from the chamber 6 - the centrifuged piece is extracted from the shell 7 The whole cycle is then recomnenced (six phases above) to make a new piece

  In another variant, it has been arranged

  turn of a melting chamber 1 containing one or more ovens several centrifugation chambers which may be intended to receive the vacuum-formed liquid metal

  in horizontal or vertical centrifugal machines.

  FIG. 3 shows a variable

  o two speakers 6 are located on the same side of the

  3 and each contain a horizontal centrifuge machine.

  In the case of Figure 4, there are two

  your 6 are diametrically opposed on both sides of

  enclosure 3, and each contain a centrifugal machine

horizontal fuger.

  There is shown in FIG.

  laughing o the device features a power carousel

  12, allowing to present one by one the shells 7 of

before the second speaker 6.

  If the oven contains enough alloy

  In order to centrifuge several pieces under vacuum, it is possible to use several identical centrifugal shells 7

  who are alternately exposed to the various pre-treatment

  The centrifugal casting, cooling, cleaning, preheating, vacuum potting in the second enclosure was thus constituted a carousel 12 o each position of a shell 7 corresponds to an operation of the above range or else a series of identical holding devices, on each of which each shell 7 is the object of the continuation of the operations of the front range

and after evacuation.

  In the variant of Figure 6, two

  6 and 13 are diametrically opposed, but

  different types: they contain, one a machine

  horizontal centrifuge, the other a centrifugal

  vertically, giving the installation a wide range of

me of possibilities.

  In a variant illustrated in Figure 7, the chamber 3 contains several furnaces. such as 1 and 21, of identical or different capacities, in order to have

  either an increased metal capacity or a great deal of

  plesse, to vary the mass of metal implemented.

  The furnaces 1, 21 are arranged such that their pouring spout 2, 22, etc ... allow simultaneous or successive emptying, in the same chute 10

in position of work.

  One of the provisions of this variant

  consists of feeding both furnaces 1 and 21 with alloys

  different ways and to achieve by centrifugation a bimetallic tube by centrifuging successively the two alloys; the first then constitutes the outer envelope

  bi-metallic tube, the second the inner liner.

  In another variant (FIG. 8), an entirely similar set is shown, different only in that the second enclosure 6 contains

  a vertical centrifuge machine 14.

  Here, the shell is also prepared outside the chamber 3, during the melting of the alloy, and then it is introduced into the chamber 6, fixed on the plate of the machine 14 by a known type of rapid locking device and surmounted by a preheated casting funnel. After evacuation of the chamber 6, and opening of the valve 5, the chute 10 is moved as for horizontal centrifugation, so that its spout

  pouring it over the funnel 15, and

  binding is centrifuged under vacuum as soon as

oven temperature 1.

  The different working methods are,

  in this variant, quite comparable to those

  stay in the horizontal process.

  According to yet another variant, it is possible to have around a melting chamber 3, containing one or

  several ovens 1, 21, etc ..., several speakers of cen-

  trifugation 6, which may be intended to receive the

  vacuum-formed liquid metal in centrifugal machines

fuger horizontal or vertical.

Claims (9)

  1 -Device of centrifugal casting comprising   first material for the elaboration, fusion and con-   control of the centrifugal alloy, and a second material for casting the alloy by centrifugal casting, and characterized in that it further comprises: a first sealed enclosure (3) provided with its own means of access , closing and evacuation, this first chamber containing the first material (1), (2) - a second sealed enclosure (6) provided with its own means of access, sealing and evacuation, this second enclosure containing the second material (7), (8); a sealed duct (4) connecting the first chamber (3) to the second chamber (6) and provided with a shut-off valve   (5) commanded from the outside to open and close   meture; and transfer means (10), (11) allowing, after opening the valve (5) of the sealed duct, to discharge   in the second material of the second enclosure (6), the   liquid binding received from the first equipment of the first girdle (3).   2 - Device according to claim 1,   characterized in that the first material includes, at the   of the first sealed chamber (3), a melting furnace (1), the emptying of which is effected by a chute (2) when makes it rock.   3 - Device according to claim 1,   characterized in that the second material includes, in the   of the second sealed enclosure (6), a mechanical roller device (8) for driving a shell centrifugation (7).   4 - Device according to claim 1,   characterized in that, in the enclosure (3), is also   chute (10) carried by a translating device   tion that can operate under vacuum, so that the pouring tube (11) of this chute can come, after opening of the valve (5), protrude into the chamber (6), while its receptacle takes place under the spout of casting (2) oven (1).   - Device according to any one of the preceding claims, characterized in that around the melting chamber (3) are arranged several centrifugation chambers (6) which can be intended to receive the   liquid metal made under vacuum in centrifugal machines   horizontally or vertically, each enclosure (6)   communicating with the enclosure (3) via a conduit (4) and a van- not waterproof (5).   6 - Device according to claim 5,   characterized in that two enclosures (6) are located one   next to the speaker (3) and each contain a machine   horizontal centrifuge (Figure 3).   7 - Device according to any one of the   Claims 1 to 5, characterized in that two enclosures (6) are diametrically opposed, on either side of 1 '   enclosure (3) and each contain a centrifuge horizontal position (Figure 4).   8 - Device according to any one of the   1 to 5, characterized in that it comprises a carousel-   feed salt (12), allowing one to   the shells (7) in front of the second enclosure (6). (fig re 5)   9 - Device according to any one of the   1 to 5, characterized in that two enclosures (6)   and (13) are diametrically opposed, but of different natures   they contain, one (6) a centrifugal machine   horizontal trifuge, the other (13), a centrifugal machine   vertical trifuger, which gives the installation a   range of possibilities (-figure 6).   - Device according to any one of the   Claims 1 to 5, characterized in that the enclosure (3)   contains several ovens such as (1) and (21),   identical or different, in order to have either an increased capacity of metal or a great flexibility, to vary the mass of metal used (Figure 7)   11 - Device according to any one of the   previous indications, characterized in that the second   enclosure (6) contains a vertical centrifuge machine (14).   12 - Method for the centrifugal casting of metal parts by implementing the following device   any one of the preceding claims, characterized   in that it comprises in combination the following phases: Phase 1 - the enclosure (3) is open. The solid materials are loaded in the oven (1); the enclosure (6) is open; - The centrifugation shell is placed on the device (9). Phase 2 - we close the enclosure (3) - we close the valve (5) - we empty the enclosure (3) - apply the power to the oven (1), to melt the metal - we prepare the Centrifugal shell on the device (9) (cleaning, preheating, washdown) Phase 3 - shortly before the material is ready to be poured,   the centrifugal shell (7) is introduced into the   encircled (6) and placed on the device intended to put it in rotation (rollers (8) - the enclosure (6) is closed   - Vacuum in the enclosure (6).   Phase 4 - the valve (5) is opened, which causes the two empty enclosures (3) and (6) to communicate - the chute (10) is displaced in such a way that   its pouring spout (11) is introduced into the shell   centrifugation, while the receptacle formed by.   its funnel is placed under the emptying spout (2) of the oven (1)   This chute (11) will have been preheated electrically during   when the metal is melted in the oven (1).   Phase 5 - the shell (7) is rotated, if the casting must take place in a rotating shell (In some cases, in fact, the casting takes place in a fixed shell, which is rotated after filling)   the oven (1) is emptied into the chute (10) which does not   be the liquid alloy in the shell (7)   the metal alloy which solidifies is thus centrifuged. under vacuum.