WO2002004149A1

WO2002004149A1 - Method and device for uphill casting, comprising a chill or core stackings with an open pouring gate

Info

Publication number: WO2002004149A1
Application number: PCT/EP2001/007915
Authority: WO
Inventors: Wolfgang Müller; Alexander Fischer
Original assignee: Hydro Aluminium Deutschland Gmbh
Priority date: 2000-07-11
Filing date: 2001-07-10
Publication date: 2002-01-17
Also published as: PL198944B1; DE10033625A1; BR0112408A; ATE260727T1; SK222003A3; EP1299202A1; CA2412935A1; SK286623B6; ES2217174T3; PL359786A1; MXPA03000288A; AU2001279730B2; DE50101632D1; AU7973001A; EP1299202B1; US20030178169A1; HUP0301499A2

Abstract

The invention relates to a method for uphill casting/low-pressure casting especially light metal alloys involving a casting plate comprising a through hole; a casting furnace lying beneath the casting plate and comprising an ascending pipe which forms an upwards-opening orifice; and a casting mould comprising a base plate which has a downwards-opening pouring gate. Said orifice is joined from below to the through hole in a sealing manner; the pouring gate pertaining to the casting mould is aligned over the through hole; molten metal is transported via the ascending pipe from the casting furnace to the casting mould, filling said casting mould; and the casting mould is displaced horizontally on the casting plate when the connection between the casting furnace and the casting mould is open and filled with molten metal, until the pouring gate is closed below by the casting plate, and the through hole is closed above by the base plate. The molten metal is then left to fall back into the ascending pipe to a point below the orifice.

Description

METHOD AND DEVICE FOR INCREASING POURING WITH A CHOCOLATE OR A CORE PACKAGE WITH OPEN POINT OPENING

The invention relates to a method and a device for increasing casting, in particular for casting light metal alloys. Compared to gravity casting, rising pouring has the main advantage of a calm, controlled pouring process. This avoids the air bubble entry and the oxide skin entry, which is associated with each swirling of the melt during casting. When core packages are used as casting molds, the detachment and entrainment of molding material in the gate and in the casting run can be avoided, which otherwise leads to a reduction in the quality of the castings.

It is generally disadvantageous with increasing pouring that the solidification process has to be waited for up to 15 minutes before the mold which has just been filled can be removed and the next mold can be brought over the casting furnace. In order to remedy this disadvantage, it has already been proposed to close casting molds in the pouring opening immediately after low-pressure casting and to remove them from the riser immediately.

Methods of the type mentioned are known from DE 198 21 419 A1 and from DE 198 07 623 A1, in which boxless molded bales (core packages) or molded boxes, each with a downwardly open pouring opening, are pushed over the mouth of the riser pipe of a casting furnace, which is under a Conveyors for these shaped bales (Core packages) or molded boxes. After the rising pouring, a closure is first closed at the upper end of the riser pipe before the molded bale (core package) or the molded box is transported on and replaced by a subsequent one.

The invention has for its object to improve a method and an apparatus of the type mentioned to increase reliability. The solution to this is based on a first ^" approach in a process for increasing casting / low pressure casting - in particular of light metal alloys - with a casting table with a passage opening, with a casting furnace lying under the casting table with a riser pipe which forms a mouth opening open at the top, with a casting mold with a base plate that has a pouring opening that is open at the bottom; the mouth opening is sealingly attached to the through opening from below, the casting mold is brought with its pouring opening over the through opening, melt is conveyed from the pouring furnace through the riser tube until it is filled into the casting mold, the mold is moved horizontally on the casting furnace with the melt-filled connection between the casting furnace and the casting mold open until the pouring opening at the bottom of the casting table and the passage opening at the top are closed by the base plate, the melt is in the riser pipe up to the mouth opening ng dropped back.

According to a second approach, a method for increasing casting / low-pressure casting - in particular of light metal alloys - is proposed with a casting table with a passage opening, with a casting furnace lying under the casting table with a riser pipe which forms a mouth opening open at the top, with a casting mold with a base plate, which has a pouring opening which is open at the bottom, the mouth opening is sealingly attached to the passage opening from below, the casting mold with its pouring opening is brought over the passage opening, melt is conveyed from the casting furnace to the casting mold until it is filled, the casting mold is left in this position until the casting has solidified, the melt will fall back in the riser pipe to below the mouth opening The casting mold is moved horizontally on the casting table with the passage opening melt-emptied until the pouring opening is closed at the bottom by the casting table and the mouth opening at the top by the base plate.

A device suitable for carrying out these processes comprises a casting table with a passage opening, a casting furnace under the casting table with a riser pipe which forms a mouth opening which is open at the top, a casting mold with a base plate which has a casting opening which is open at the bottom; the mouth opening is sealingly attached to the passage opening from below, the casting mold is attached to the passage opening from above, means for horizontally displacing the casting mold on the casting table and means for simultaneously maintaining a positive pre-pressure of the base plate of the casting mold with respect to the casting table.

With the means specified herewith, a complete dispensing with a slide closure is possible, rather the pouring of the casting mold and the passage opening in the casting table or the mouth opening of the riser pipe are brought into connection with each other for casting / mold filling and melt is conveyed into the casting mold until it is filled. Then, after the first batch, immediately after the casting / mold filling, the casting mold is shifted while the melt is still liquid in the downwardly open sprue opposite the opening of the pouring table or the mouth of the riser pipe on the casting table in such a way that the previously uniform melt column in the riser pipe and in the sprue directly and exclusively by moving the casting mold in relation to the opening in the casting table or the Mouth opening of the riser pipe is sheared off. The top of the casting table, which can be reinforced with an inserted ceramic plate or rail, and the underside of the base plate of the casting mold, which lie flat on one another, act as a closure means. On the other hand, after the second batch after casting / filling the mold, the solidification of the cast part is first waited until there is only liquid melt in the sprue, which is then dropped back into the riser pipe by lowering the pressure before the emptied sprue opposite the opening of the casting table or the mouth of the riser on the casting table is moved so that the next mold can be adjusted.

While in the first process an active pressure application from above makes sense, in the second process the pressure is generated via the melt in the riser pipe.

In order to prevent the casting mold from floating during casting, the surfaces mentioned can be pressed against one another with contact pressure. This is possible by means of horizontal rails or roller sets which are elastically attached to the casting table and which act to press the casting mold onto the casting table when moving on fixed horizontal edges or rails of the casting mold, or by means of horizontal rails or roller sets which are arranged elastically on the casting mold and which are used to press the casting mold on Interacting the casting table with horizontal edges or rails fixed to the casting table. Suitable material combinations for these surfaces are to be selected depending on the type of casting metal.

The feeding of the casting molds into the casting position can take place in different ways, either the casting mold being placed on the casting table from above in such a way that the passage opening or the mouth opening is openly connected to the pouring opening, or alternatively the casting mold is in each case horizontally so over the Casting table is fed that the passage opening or the mouth opening is openly connected to the gate opening. After pouring and moving, the mold can be stopped in a position in which the casting table is cooled under the sprue opening. In addition to this, the casting mold with the sprue opening can be moved over a cooled distance of the casting table when moving. These two measures result in rapid solidification of the melt in the sprue, after which the casting mold can be lifted off the casting table or the corresponding conveying means while the solidification is not yet complete.

In the case of small, rapidly solidifying castings, it is expedient to arrange two casting molds in tandem on a base plate with two sprue openings. In the case of larger, more slowly solidifying castings, it is possible to provide a carousel arrangement in which a plurality of casting molds are built up on a common base plate with a ring of sprue openings.

Further advantageous embodiments of the method and suitable devices result from the subclaims, to which reference is hereby made.

As far as the increasing casting / low-pressure casting according to the invention is concerned, this initially relates to methods and devices in which a controllable gas pressure is applied to the melt level in the sealed casting furnace, which causes the melt in the riser pipe to rise or fall back. However, other methods and devices are also included that can regulatably promote the melt in the riser pipe, e.g. Magnetic pump arrangements at the lower end of the riser pipe in the casting furnace.

Preferred embodiments of the invention are described below with reference to the drawings. Here show the Figures 1 to 8 an apparatus according to the invention with casting table, casting furnace and two molds, with the individual phases;

Figure 1 Structure of a form in the casting furnace; Form 1 in casting position; Form 2 is open;

Figure 2 casting the mold 1; Form 2 is closed;

Figure 3 form 2 in the casting position; Form 1 in the freezing position;

Figure 4 casting the mold 2; Form 1 is open;

Figure 5 casting mold 2; Removal from mold 1;

Figure 6 Form 1 in the casting position; Form 2 in the freezing position;

Figure 7 casting the mold 1; Form 2 is open;

Figure 8 casting the mold 1; Demolding of form 2;

FIG. 9 shows a casting installation according to the invention with several individual molds a) in plan view b) in side view;

Figure 10 shows a casting plant according to the invention with a

Melting furnace, two casting stations and four casting furnaces. Figures 1 to 8 are first described jointly, insofar as the details match. A horizontal casting table 11 has a passage opening 12 which is covered with an outer lining 13 and an inner lining 14. Under the casting table 11 there is a casting furnace 21, which has a riser pipe 22, which is inserted sealingly into the casting furnace and dips into the melt 23 contained therein and has an opening 24 at the top. An arrow 25 indicates that compressed air can be applied to the casting furnace 21, so that a melt column 26 rises in the riser. On the casting table there are two casting molds, designated by the numbers "1" and "2", which have a common base plate 30. This base plate 30 has sprue openings 31, 32, which can be brought to coincide with the passage opening 12 by transverse displacement of the base plate 30. The gate openings 31, 32 are each provided with linings 33, 34. The casting molds 1, 2 constructed on the base plate 30 each have holders 35, 36, 37, 38 with actuating cylinders 39, 40, 41, 42 which act on mold halves 43, 44, 45, 46. A central mandrel 47, 48, the suspension of which is not shown in detail, is located in the middle between the mold halves. Together with the closed mold halves, this forms a hollow cylinder with a slightly conical inner shape and external ribbing. The casting to be produced with the molds 1, 2 shown can in particular be a cylinder liner made of light metal for internal combustion engines. -Volume and shape changes of the casting when solidifying are neglected in all representations.

In the embodiment shown, the riser pipe 22 seals against the casting table 11 at the bottom in the area of the passage opening 12. For this purpose, when the riser pipe 22 is elastically suspended in the casting furnace 21, the casting furnace 21 can be moved in height from below against the casting table 11. The respective pouring opening 31, 32 in the base plate 30 lies in a sealing manner at the upper exit of the through opening 12. Lowering the casting furnace is particularly advantageous in order to replace an empty casting furnace with a filled casting furnace.

In Figure 1, a pre-pressure is built up in the casting furnace, which allows the melt column 26 to rise slightly above the mouth opening 24. The casting mold 1 is assigned to the casting furnace 21 by moving the base plate 30 to the right into a first casting position. The casting mold 1 is closed, as indicated by arrows, and ready for casting. The mold 2 is open, as indicated by arrows and removed from the mold.

In Figure 2, the form in the casting furnace 21 is increased so that the melt column 26 has risen and the mold 1 is completely filled. The casting process as such has already ended here. The mold 2 is now shown closed as indicated by arrows.

In FIG. 3, the base plate 30 is shifted to the left into a second casting position, the melt column in the casting mold 1 having been sheared off between the casting table 11 and the base plate 30 and a finished casting being produced in the casting mold 1. The casting mold 2 is assigned to the casting furnace 21 by moving the base plate 30 to the left into a second casting position and is ready for the casting process in the closed position. Immediately after shearing off the casting mold 1, the melt column 26 is initially allowed to fall back in the riser pipe 22 to slightly above the mouth opening 24.

In FIG. 4, the casting mold 1 is opened as indicated by arrows, the finished casting still being held on the central mandrel 47. In the casting mold 2, the melt column rose by increasing the pressure in the casting furnace, so that the casting mold is completely filled. The actual casting process has already been completed here. 5, the mold 1 is closed again, the finished casting 49 being completely removed from the mold. The mold 2 is shown as in Figure 4 during the melting process.

In FIG. 6, the base plate 30 is again shifted to the right into the first casting position, so that the casting mold 1 is again assigned to the casting furnace 21. The melting column in casting mold 2 has been sheared off, so that a finished casting can be seen in the casting mold. The mold 2 is still closed to wait for the solidification process. The casting mold 1 is prepared for the next casting process, the melt column 26 ending slightly above the mouth opening 24 in the riser pipe 22.

In FIG. 7, the casting mold 2 is open, as indicated by arrows, a finished casting still resting on the central pin 48. In the casting mold 1, the melt column 26 has risen by increasing the admission pressure in the casting furnace 21 and thus the column has been filled, so that the actual casting process has already ended here.

In Figure 8, the casting 50 is removed from the mold 2 and the mold is closed again for the next casting process. The casting mold 1 is shown in the corresponding position with FIG. 7, by moving the casting mold with the base plate, the melt column 26 between the base plate 30 and the casting table 11 will be sheared off in the next moment.

FIG. 9 shows a casting table 51 with a passage opening 52 and with cooling positions 53, 54 indicated by arrows. Under the casting table is a casting furnace 61 with a riser pipe 62 which is filled with melt. The mouth opening 64 of the riser pipe 62 connects to the passage opening 52 from below. Three individual molds 71, 72, 73 are placed on the casting table 51. The mold 71 lies with the sprue 74 over the casting furnace 61 and is in the process of being poured. The shape 72 is already behind the opening 52 shifted to the left, whereby the melt column has been sheared off and is in a position in which the sprue 75, 76 in the mold 72, 73 lies above a cooling region 53 of the casting table. The mold 73 is displaced further and is in a position in which the sprue 75, 76 in the mold 72, 73 lies over a cooling region 53, 54 of the casting table, with solidification taking place in the sprue 76. From here, the mold can be moved further or lifted off the casting table. Arrows 77, 78 indicate the effect of a form which prevents melt from escaping when the casting mold is filled. The effect of a higher active pressure for feeding is indicated by an arrow 79.

A device according to the invention is shown in top view in FIG. 10, a casting table 91 being designed only as narrow paths. The casting table here has two casting stations 92, 93 with passage openings 94, 95 and two solidification stations 96, 97. Casting molds 101, 102 can each be placed on the casting stations for casting from above, whereby they can be moved after casting and then the positions of the here assume molds 103, 104 designated during solidification. Pouring furnaces ND1, ND2, ND3, ND4 can be brought into the vicinity of a melting furnace 111 and from there can be moved into a stopping position in front of the casting stations 92, 93, into a casting position and into a stopping position behind the casting stations 92, 93, so that empty ones in each case Pouring furnaces can be refilled at the melting furnace 111 and, after emptying a pouring furnace, a filled pouring furnace can be refilled from a waiting position into the pouring position under the pouring table. At least one of the

Casting stations 92, 93 of the casting table should always be ready for casting, so that there is no interruption in production during the changing of a casting furnace. The two casting stations can normally also be operated in parallel in order to increase the production rate.

Claims

claims

1.Method for increasing casting / low-pressure casting - in particular of light metal alloys - with a casting table with a passage opening, with a casting furnace lying under the casting table with a riser pipe that forms a mouth opening that is open at the top, with a mold with a base plate that is open at the bottom Has sprue opening; the mouth opening is sealingly attached to the passage opening from below, the casting mold is brought with its pouring opening over the passage opening, melt is conveyed from the casting furnace to the casting mold via the riser pipe, the casting mold is horizontal with the melt-filled connection between the casting furnace and casting mold open moved on the casting table until the pouring opening at the bottom of the casting table and the passage opening at the top of the base plate are closed, the melt is allowed to fall back in the riser pipe to below the mouth opening.

2. Process for increasing casting / low pressure casting - in particular of light metal alloys - with a casting table with a passage opening, with a casting furnace lying under the casting table with a riser pipe which forms a mouth opening which is open at the top, with a casting mold with a base plate, which has a downwardly open pouring opening, the mouth opening is sealingly attached to the passage opening from below, the casting mold is brought with its pouring opening over the through opening, the riser pipe is used to melt the casting furnace until it is filled into the The casting mold is conveyed, the casting mold is left in this position until the casting has solidified, the melt is allowed to fall back below the mouth opening in the riser pipe, the casting mold is moved horizontally on the casting table with the passage opening melt-emptied, until the pouring opening at the bottom of the casting table and the mouth opening at the top is closed by the base plate.

3. The method according to any one of claims 1 and 2,

wherein the casting mold is placed on the casting table from above in such a way that the passage opening or the mouth opening is openly connected to the pouring opening.

4. The method according to any one of claims 1 or 2,

the casting mold is fed horizontally over the casting table in such a way that the passage opening or the mouth opening is openly connected to the pouring opening.

5. The method according to any one of claims 1 to 4,

whereby during the rising pouring and the shifting of the casting mold, the latter is held against the casting table or the riser pipe with pre-pressure.

6. The method according to any one of claims 1 to 5,

wherein the rising pipe is held against the casting table or the base plate of the casting mold with pre-pressure during the rising casting and the displacement of the casting mold.

7. The method according to any one of claims 1 or 3 to 6,

after moving the mold, the mold is stopped in a position in which the mold table is cooled under the gate.

8. The method according to any one of claims 1 or 3 to 7,

wherein when the mold is moved, it is guided with the sprue opening over a distance of the casting table that is cooled.

9. The method according to any one of claims 1 to 8, wherein two molds are alternately built on a base plate with two pouring holes, poured and removed from the mold, the base plate is pushed alternately with the sprue openings over the passage opening or on the mouth opening.

10. The method according to any one of claims 1 to 8, wherein a plurality of molds are sequentially built up on a base plate with a ring of pouring holes, poured and demolded, wherein the base plate is rotated like a carousel with the sprue openings over the passage opening or onto the mouth opening ,

11. Device for increasing casting / low pressure casting - in particular for casting light metal alloys - with a casting table with a passage opening, with a pouring furnace under the casting table with a

Riser tube, which forms a mouth opening open at the top, with a casting mold with a base plate, which has a pouring opening which is open at the bottom, the mouth opening is sealing against the bottom

Passage opening set, the casting mold with its pouring opening is from above to the

Passage opening scheduled,

characterized by means for horizontally displacing the mold on the casting table and means for simultaneously maintaining a positive pre-pressure of the base plate of the casting mold with respect to the casting table.

12. The device according to claim 11,

characterized,

that the mold has coolant above a non-cooled gate area.

13. Device according to one of claims 11 or 12,

characterized by horizontal rails or roller sets which are elastically fastened to the casting table and which act on the casting table when the casting mold is pushed onto fixed horizontal edges or rails of the casting mold.

14. Device according to one of claims 11 or 12,

characterized by horizontal rails or roller sets arranged elastically on the casting mold, which interact to press the casting mold on the casting table with horizontal edges or rails arranged firmly on the casting table.

15. The device according to one of claims 11 to 14,

characterized by means for pressing the riser pipe against the casting table or the casting mold.

16. The apparatus of claim 15,

characterized by a riser pipe suspended elastically in the casting furnace and height adjustment means for the casting furnace.

17. The device according to one of claims 11 to 16,

characterized by two molds placed on a common base plate with two sprue openings, in particular permanent molds, and displacement means for alternately displacing the base plate.

18. Device according to one of claims 11 to 16, characterized by a plurality of molds, in particular permanent molds, placed on a common base plate with a ring of sprue openings, and rotary drive means for rotating the base plate.