US3905419A

US3905419A - Device for rise casting into a mold

Info

Publication number: US3905419A
Application number: US456154A
Authority: US
Inventors: Oskar Tenner
Original assignee: GRAVICAST PATENT GmbH
Current assignee: GRAVICAST PATENT GmbH; GRAVICAST PATENTVERWERTUNGSGE GmbH
Priority date: 1970-09-29
Filing date: 1974-03-29
Publication date: 1975-09-16
Anticipated expiration: 1992-09-16

Abstract

A device for rise casting into a mold is provided with an upwardly extending casting nozzle connectable with the ingate of a mold arranged horizontally movable above the casting nozzle and wherein the melt in the ingate solidifies after the casting operation. A horizontally slidable plate serves as a shutoff device for interrupting the still liquid melt in the narrow channel between the discharge aperture of the nozzle and the inlet of the ingate of the mold. The slidable plate is slidably supported in the bottom wall of the mold and at least the face of the slidable plate facing the casting nozzle is covered with refractory material. The slidable plate is lockable in a position in which it closes the ingate of the mold.

Description

United States Patent 1191 Tenner DEVICE FOR RISE CASTING INTO A MOLD [75] Inventor: Oskar Tenner, Rossatz, Austria [73] Assignee: Gravicast Patentverwertungsge-Gesellschaft mbH, Vienna, Austria 22 Filed: Mar. 29, 1974 21 Appl. No.: 456,154

Related US. Application Data [63] Continuation of Ser. No. 184,491, Sept. 28, 1971,

14 1 Sept. 16, 1975 Primary Examiner-Robert D. Baldwin Attorney, Agent, or FirmWaters, Schwartz & Nissen ABSTRACT A device for rise casting into a mold is provided with an upwardly extending casting nozzle connectable with the ingate of a mold arranged horizontally movable above the casting nozzle and wherein the melt in the ingate solidifies after the casting operation. A horizontally slidable plate serves as a shutoff device for interrupting the still liquid melt in the narrow channel between the discharge aperture of the nozzle and the inlet of the ingate of the mold. The slidable plate is slidably supported in the bottom wall of the mold and at least the face of the slidable plate facing the casting nozzle is covered with refractory material. The slidable plate is lockable in a position in which it closes the ingate of the mold.

5 Claims, 9 Drawing Figures PATENTED SEP I 6 B75 SHEET 2 BF 3 DEVICE FOR RISE CASTING INTO A MOLD This is a continuation of application Ser. No. 184,491, filed Sept. 28, 1971, now abandoned.

The invention relates to a device for rising pouring of 5 material for finished or semi-finished castings into a mold connected with a casting nozzle for castings the ingates of which solidify upon completion of the casting process, as it is the case with particularly large castings or sand castings, in which device a shut off means in the form of a slide is used to interrupt the still liquid string of melt between the casting nozzle and the mold cavity.

The Austrian patent No. 239,979 discloses a crucible with a closable discharge nipple, to which a blocking member is attached which has a disc that can be rotated relatively to a plate having an eccentrically located opening. Such sliding plates in the casting device usually have the disadvantages that in the case of large castings or sand castings, the mold has to be kept in contact with the casting nozzle until the ingate has solidified. This results in a very slow production of the castings. Furthermore, it is very difficult to control the speed of the feed, since there is always the danger of a freezing or of a washout and, thus, no uniform control of the speed of casting can be obtained. A further disadvantage of the described closure device is its flow pattern disturbing effect, which leads to turbulences that cause a high rate of waste.

In order to overcome this disadvantage of a low speed production caused by a slow solidification and to meet the solidification shrinkage at the same time, it has already been proposed in the Austrian patent specification No. 251,780 to provide in a pressure casting device, in which the casting material is forced under pressure from a container situated beneath the mold through a standpipe into the mold, a pressurized feeding container between the mold and the standpipe, which takes up metal to supplement the mold charge and is provided in its bottom part with a closure valve in the form of a perforated plate and with a device for the application of a pressure that is independent of the filling pressure of the metal supply contained in the pressurized feeding container. This arrangement produces a considerably improved utilization of the casting device, since every mold can immediately be replaced after filling together with the pressurized feeding container. The expensive pressurized feeding container is, however, a disadvantage; it is also very subject to breakdowns and thus causes high operating expenses owing to substantial sealing problems and constant danger of freezing. Even if a heating device is used, numerous problems arise because the casting operation has to be carried out at a higher temperature, which is highly undesirable, or there is increased wear as a result of the heating operation, or uncontrollable flow conditions occur owing to the shape of the openings, etc.

It is also known from the Austrian patent specification No. 285,840 to place the controlling device for the casting speed at a distance in front of the casting nozzle, in order to create an equalization chamber between the casting nozzle and the controlling device to transport the melt with a controlled flow to the mold. This device, too, has the disadvantage of a small impulse rate when the casting solidifies only a considerable time after completion of the casting process. Also, with this device it is not always possible to obtain maximum results.

An object of the invention is to overcome the disadvantages of the conventional devices and to retain their advantages. The invention resides substantially in a device for the controlling of the speed of casting which is located at a distance in front of the casting nozzle and in the fact that the slidable plate is guided in the bottom of the mold and has at least at the surface facing the casting nozzle and cooperating with it a layer of refractory material, the mold being provided with at least one feeder which is connected with the mold cavity. The position of the slidable plate in the mold (e.g. die, ingot, sand mold, etc.) comprises a considerable constructional simplification with regard to the convential constructions mentioned above, because the distance from the casting nozzle to the mold cavity is shortened, so that there is only a negligible effect on the How in this area. In this invention, the slidable plate is used purely asa shutoff device, since it is relieved of any controlling function of the casting speed by the controlling device located at a distance in front of the casting nozzle. The slidable plate can, therefore, be designed to obtain the optimal flow conditions. A negative effect of the slidable plate on the flow conditions is thus prevented. The controlling device for adjusting the casting speed to the desired value may consist of any desired conventional shutoff device, e.g. with large series by selecting the diameter of a nozzle, etc.

The material required to make up for the shrinkage is kept in the feeder in the mold itself. This causes a certain increase of the circulating material and of the machining costs. These negligible disadvantages, however, can easily be accepted when there is an adequate design of the feeder, since they carry almost no weight in comparison with the overwhelming advantage of a considerably increased production. If one assumes a casting time of one second for the filling of the mold and if it is possible to save an additional second during the solidification time of the ingate by means of this device, a doubling of the possible production by means of the invention is already achieved.

Since, as is well known, refractory material has a considerably lower heat conductivity than metal, it prevents an undesirable cooling of the casting nozzle and of the casting material, so that the melt need not be unnecessarily superheated and the casting can be done at an optimal temperature. In addition, the danger of freezing is considerably reduced, on the one hand, owing to the better heat insulation through the refractory material of the sliding plate mentioned above, and on the other hand, because the device is subjected to extreme temperatures for a very short period only, viz. during the duration of one casting operation.

The manner in which the slidable plate is covered by the refractory material, at least on the surface facing and cooperating with the casting nozzle, depends on the given conditions. It is possible, eg to insert a mat, plate, etc. made of refractory material between the casting nozzle and the surface of the slidable plate facing it. According to this invention, it is, however, often more advantageous, when the slidable plate at least the part cooperating with the casting nozzle consists of refractory material which moves with the slidable plate.

According to a preferred embodiment of the invention, the slidable plate is perforated and placed in an aperture of the mold extending over the entire width of the same, whereby its length corresponds at least to the axial dimension of the aperture. Thus, it is possible to introduce the slidable plate quite easily during the preparation of the mold and to shift it after the filling of the same. If, according to a further development of the invention, the walls of the aperture for the slidable plate consist of molding sand, there are special advantages, since in such a case, the slidable plate is simply inserted during molding operation and thus contributes to the formation of the aperture.

Depending upon the type of the casting material, the refractory material for the slidable plate may be selected to have a higher or lower degree of heat conductivity or have a greater or smaller strength, respectively. It is particularly advantageous when the refractory material consists according to the invention of a core mixture, ceramics or mineral wool, e.g. wool of kaolin, or of a sintered material. The choice of the material depends upon the material to be processed. This material may be placed into a slidable plate made of steel or into a slidable plate made of cast iron, e.g. in the shape of a ring or of a plate, or this material may cover the slidable plate in the dangerous area, or the slidable plate may consist of this material. In all examples, provision can be made that the casting nozzle is protected from cooling by the refractory material, but that an acceleration of the cooling of the ingate occurs through the metallic part of the slidable plate, which thus acts as a cooling agent and, if necessary, may additionally be cooled. Thus, it is easier to make allowance for the desire that a solidification of the casting material in the casting nozzle has to be absolutely prevented, but that a quick solidification of the material cast into the mold is desirable at least at the ingate of the mold, in order to achieve a rapid cycle time. In this way'it is also possible to influence the cooling speed of the cast melt at will.

Depending upon the shape and upon the casting material, the slidable plates may be used only once, or if cleaned, may be used several times. A further advantage is that the described device can easily be automated.

The method of producing the device of the invention is basically characterized by the fact that the slidable plate is inserted into the mold during the formation of the mold and is surrounded by the material of the mold. As mentioned above, it is thus possible to save an extra part for the forming of the opening through which the slidable plate moves.

The drawings show schematic examples of the invention.

IN THE DRAWINGS FIG. 1 shows a vertical section of a complete casting device.

FIG. 2 shows a vertical section of a detail of FIG. 1.

FIG. 3 is a view from above, of FIG. 2.

FIG. 4 shows a view along the line IV-IV of FIG. 5 of an automated molding device. FIG. 5 is a section along the line VV of FIG. 4.

FIG. 6 is a top view of a slidable plate.

FIG. 7 is a section along the line VIIVII of FIG. 6.

FIG. 8 shows a top view of another slidable plate. and

FIG. 9 is a side view of the slidable plate shown in FIG. 8.

Referring to FIG. 1, a supply chamber 1 has mounted therein a horizontal tube 2 constituting an equalization chamber 3. At one end of the tube 2 is arranged a trans- 4 versely disposed inlet nozzle 4 for the melt which can be closed by a vertically movable plug member 5. Horizontally spaced from the nozzle 4 and at the other end of the tube 2, is arranged a casting nozzle 6 covered by a horizontal base plate 7 on which themold 8 or a sand mold is placed. An induction heating device (not shown) is connected to the openings 9 of the supply chamber 1. This inductive heating makes it possible to maintain a controlled casting temperature of the melt. The relatively large cross-section of the supply chamber 1 provides a uniform heating of the melt for the necessary flow of the melt, whereas the flow in the equalization chamber formed by tube 2 is not influenced by the flow caused by the heating. The supply chamber I is either connected with the melting furnace or is filled intermittently to maintain a constant melt level, so that the ferrostatic height, upon which the casting speed depends remains substantially unchanged.

The FIGS. 2 and 3 show that the base plate 7 encircles the nozzle 6 and is insulated against it by means of a sleeve 10 of heat insulating material which keeps the heat losses as low as possible. The mold 8 has a frame 11 as well as a bottom plate 12. The bottom plate 12 is provided with an oblong recess 13, which continues through one wall of the frame 11. In this recess 13 lies a slidable plate 14, one portion 15 of which consists of refractory material which comes immediately in contact with the melt; this portion 15 is so constructed that it has only a negligible influence on the flow conditions. To insure its closure position, the slidable plate need not be rounded; it must only be insured that when the slidable plate 14 is moved to its closure positionwhich as a rule occurs very suddenly-a closing of the ingate 16 of the mold is achieved, possibly with a partial destruction of the portion 15, so that the mold can be transported without any spilling of the melt in the mold.

Next to ingate 16 is the mold cavity 17 of mold 8 which is in communication with a feeder channel 18.

The slidable plate 14 has a transverse groove 19 which cooperateswith locking bolt 20 which is pivotally mounted on the frame 11 of the mold 8, so that it can be rotated about an axis 20 to engage the groove 19 after the slidable plate 14 has been inserted and closed, so that an undesired removal of the slidable plate during the transport of mold 8 is prevented.

Between the nozzle 6 and the mold 8 there may, of course, be arranged a wear-resistant ring. Furthermore, it is possible to provide the slidable plate 14 with water cooling means, which starts to work after the transport of mold 8. l

The FIG. 4 and 5 showthe application of the invention in an automated molding device. Molded sand packs 21. are fed one after the other onto a horizontal base 22 to the nozzle 6. During the molding of these sand packs 21, the opening for the slidable plate 14 may also be produced by the insertion of a suitable core, or the slidable plate 14 itself may be used as such a core. The slidable plate 14 has a hole 23, which is shaped according to the cross-section of the nozzle 6 and the ingate 16 with regard to favorable fluid techniques. The slidable plate in the example shown here consists entirely of refractory material, e.g. core material, ceramics, not pressed, pressed or matted mineral wool (particularly wool of kaolin) or a sintered material. Upon completion of the casting process, a hydrau lic plunger 24, which is operated by a double-acting cylinder attached to pressure

medium pipes

26, 26, displaces the slidable plate 14 and closes the ingate 16. The sand mold closed in this manner is now ready for further transportation. The hydraulic cylinder 25 can be automatically controlled by a fluid level measuring device.

According to FIGS. 6 and 7, the slidable plate 14' consists of two layers. The lower layer 27 consists of a refractory material and covers the surface of the slidable plate facing the casting nozzle. The upper layer 28 is metallic, e.g. made of cast iron, cast steel, etc. ln the range of this layer, the hole 23 of the slidable plate 14 is lined with a ring 29 made of refractory material.

In the embodiment of the slidable plate 14" according to FIGS. 8 and 9, an insert 31 made of refractory material surrounds the hole 23 in the metallic base plate of the slidable plate at the face contacting the casting nozzle.

If desired, the feeder 18 may be lined with exothermic material in all embodiments of the invention.

What I claim is:

l. A device for rise casting by means of ferrostatic pressure into a mold, comprising: an upwardly extending casting nozzle adjacent the ingate of the mold and having a discharge aperture aligned with an inlet of said ingate, shutoff means including a slidable plate having a bottom surface, for interrupting the still liquid melt between said discharge aperture and said inlet; means arranged at a distance ahead of said nozzle for controlling the casting speed; means for slidably supporting said plate in a bottom wall of the mold; a surface layer of said plate facing and contacting said nozzle in the casting position of the mold and in the shut-off position of said plate consisting of a refractory material; a surface layer of said plate facing and contacting said ingate in the shut-off position of said plate consisting of a material having a higher thermal conductivity than that of the refractory material; and feeder means in the mold above said ingate and in communication with the interior of the mold.

2. The device as defined in claim 1, wherein said plate has an aperture and is movably arranged in a recess in the bottom of the mold, said recess extending the width of the mold, and the length of said plate corresponding at least to the length of said recess.

3. The device as defined in claim 2, wherein the mold is a sand mold, and the walls of said recess are formed by the sand of the mold.

4. The device as defined in claim 2, wherein said plate includes a metallic base coated with a refractory material in the area contacting the melt when said plate is in the closed position, the refractory material on said base covering also a wall of said plate aperture in the form of a ring-shaped member.

5. The device as defined in claim 1, wherein the bottom wall of the mold has a lower surface which is flush with said bottom surface of the plate.

Claims

1. A device for rise casting by means of ferrostatic pressure into a mold, comprising: an upwardly extending casting nozzle adjacent the ingate of the mold and having a discharge aperture aligned with an inlet of said ingate, shutoff means including a slidable plate having a bottom surface, for interrupting the still liquid melt between said discharge aperture and said inlet; means arranged at a distance ahead of said nozzle for controlling the casting speed; means for slidably supporting said plate in a bottom wall of the mold; a surface layer of said plate facing and contacting said nozzle in the casting position of the mold and in the shut-off position of said plate consisting of a refractory material; a surface layer of said plate facing and contacting said ingate in the shut-off position of said plate consisting of a material having a higher thermal conductivity than that of the refractory material; and feeder means in the mold above said ingate and in communication with the interior of the mold.