US2864141A

US2864141A - Molds

Info

Publication number: US2864141A
Application number: US471463A
Authority: US
Inventors: Vallak Enn
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-12-03
Filing date: 1954-11-26
Publication date: 1958-12-16
Anticipated expiration: 1975-12-16

Description

K A L L A v E b D L O M Filed Nov. 26, 1954 INVENTORZ Erin United States Patent 2,864,141 Moms Enn Vallak, Grytliyttan, Sweden Application November .26, 1954, Serial No. 471,463 Claims priority, applicationSwedenDecember 3, 1953 4 Claims. (Cl.22-144) The present invention relates: to: certain new and useful improvements in chill molds. and. other foundry molds.

In the processof casting steel. or other metals-into castings or ingots so-called chill-molds; preferably made of cast iron, are usually employed. Suchchill-molds are easy to manufacture and they render possible a simple casting method. A drawback is that the costs for the chill-molds are. high since the molds will be worn out after a certain number of tappings. Several attempts have been made to use water-cooled molds in order thereby to increase the length of life: of the mold and to enable the surface; layer of the ingot to solidify considerably more rapidly thanin a conventional chill-mold of castiron. One inconvenience in. water-cooled chill-molds, however, resides, in their. being: comparatively complicated. Since, hithertofore, it has beenconsidered to be necessary to 'use a large number of chill-molds the total volumetric capacity of. which correspond to the rate of flow of'steel' poured fromthe ladle, it will be seen. also that the means provided for the water-cooling will be fairly complicated; A; known water-cooled chill-mold of this: kind mainly consists, for. example, of a double-walled tube of, copper orthe like. Asthe steel is poured into thischill-rnold a surface layer of the steel rapidly solidifies adjacent the inside of the chill-mold so as to form a shell. After a few seconds or minutes, depending on the size of the ingot, the casting may be withdrawn from the chill-mold and introduced into a so-called soaking pit. Due to the constructional form of the chill-mold, however, it is a difficult and time-wasting task to remove the chill from the chill-mold since the mold must either be lifted from the ingot or the ingot be lowered from the chill-mold.

The present invention has for its main objectto avoid these inconveniences by means of a mold adapted to be cooled by water or in any other suitable manner and constructed so as to be divisible into two or more sections carried on a base which forms the bottom of the chill-mold.

For the object stated, according to the invention, each of said sections has associated therewith a hollow cooling jacket having an inlet and an outlet, and said sections are arranged to be retained in close juxtaposition during the operation of pouring the metal into the mold while being separable to enable the ingot or casting to be removed from the mold after finishing the casting opera tion. The water-cooled mold may for instance consist of two substantially identical halves which, for instance, are separable by means of two pneumatic cylinders or any other power mechanism. Preferably, the bottom or base or bed of the mold is made in such a manner as to be separable from the rest of the mold and so as to be transportable as a separate unit whereby the ingot or casting can be carried away resting on said bottom or base without carrying the remaining part of the mold with it. Also the base may be water-cooled but could also remain uncooled.

The invention will now be explained more in detail,

2,864,141 Patented Dec. 16, 1 -958 lCe 2 reference being had to the accompanying drawing in which:

Fig. 1 is a vertical section through the two-part mold,

Fig. 2 is a plan view thereof and Fig. 3 illustrates the base of the mold with a completed ingot or casting standing thereon after removal from the mold.

Referring to the drawing, in the embodiment illustrated therein the chill-mold, being substantially frusto-conical in shape, for instance, consists of two halves 1 and 2 each having a cooling cavity 1a and 2a, respectively, for the circulation of any suitable cooling fluid such as water or other liquid fluids, vapor, air or other gaseous fluids. The cooling fluid may be supplied at 3 and dis charged at 3a. The parts 1, 2 of the chill-mold may suitably be made of cast-iron or any other heat-resistant material. The joint between said parts is shown at 13. Also the bottom or base or bed 4 of the chill-mold may possibly be provided with a cooling jacket and cooled by means of any suitable cooling fluid which may then be conducted upwards into the cavities 1a, 2a. The base 4, consisting for example of cast-iron or any other heatresistant material, is suitably made so as to be readily separablev from the parts. 1 and 2. The base 4 may be transportable on wheels 5 or in any other manner. The base 4 forms with the wheels 51; carriage. 4a. Preferably, its upper face has one or more bores or recesses 6 or the like provided therein.

In. operation, the steel or other metal is poured into the space 1c of the cooled chill-mold in the conventional manner while the parts 1 and 2 are retained in close juxtaposition. by any suitable means, for instance consisting of pairs of pneumatic or hydraulic cylinders 10 11. The top cylinders 10 are arranged opposite. one an.- other and mounted in a frame 12. Their piston rods ltla are secured to the respective half 1, 2 of the mold so that said halves will be. forced towards one another when the pistonrods. 10a movein a. direction towards the mold so as to close the joint 13 while said joint will be opened when piston rods 10a move away from the mold. The lower cylinders 11 with their piston rods 11a are mounted in similar manner in a frame 14 which may be associated with the frame 12 in one structure. Fluid connections 10b and 11b are provided for the

cylinders

10 and 11, respectively.

In a short period after pouring-in the metal into the space 10, a layer of metal will solidify adjacent the inner wall-surface of the chill-mold owing, in part, to the steel or metal having considerably higher heat conducting properties than the material of the chill-mold, and, in part, to the fact that the cooling fluid will act to carry away large amounts of heat from the comparatively thin walls of the chill-mold. As soon as this surface layer has reached a sufiicient thickness the ingot is removed from the chill-mold by separating the mold parts 1, 2 at the joint 13. After closing the chill-mold at the joint 13 by means of the

cylinders

10, 11 the mold is ready for receiving a fresh charge. The ingot 7 is suitably removed by moving the carriage 4a laterally, without carrying the mold parts 1, 2 with it, said parts being removed from the carriage 4a in any suitable manner. The ingot 7 standing upright on the base 4 is prevented from falling if some of the molten metal is allowed to flow into the recesses 6 to form therein suitable supports. After the ingot has been lowered into a soaking pit, the carriage 4a can be returned to the same, or to another chill-mold. It would also be possible, however, to let the base 4 remain all the time in the vicinity of the mold parts 1, 2, and to remove the chill from the separated two-part chillmold in any other suitable manner.

The pressure of the cooling fluid should be low in order, in the event of cracks being present in the wall of chill-mold, to prevent any cooling fluid from penetrating into the ingot where it might cause explosion or other damage.

If it is desired to use a hot top 8, it may be introduced into the chill-mold (Fig. 1) or applied to the ingot (Fig. 3) together with a top cover 8a after removing the ingot from the chill-mold. In the latter case the hot top 8, 8a may be made in the form of a box having its bottom 8a facing upwards, or in the form of a ring.

Above the chill-mold or chill-molds a protective hood 9, for instance, of refractory material, could be mounted serving to protect the mold and its associated operating mechanism against splashing of steel due to a tapping failure, said hood having such a shape as to carry away the molten splashes in the most suitable manner. Since the mold is made in sections, it may, as illustrated in Fig. 1, have a shape tapering towards both ends, since nevertheless the ingot may be easily removed from the mold.

What I claim and desire to secure by Letters Patent is:

1. A mold for casting metals comprising a movablysupported bottom part and an upper part removable from said bottom part and comprising at least two mold sections each having a hollow cooling jacket with inlet and outlet for a cooling medium, said mold sections confining together with said bottom part a hollow space for liquid metal and being separable from each other, means for maintaining said sections in closed juxtaposition during the casting operation, means for separating said sections after at least a skin on said liquid metal has been solidified so as to disengage them from the ingot obtained by said solidification, means for removing said bottom part with said ingot thereon laterally, and means for retaining the ingot on said bottom part during transport.

2. A set of molds for casting metals in which each mold is constituted by a movably-supported bottom part, and an upper part removable from said bottom part and comprising at least two mold sections each having a hollow cooling jacket with inlet and outlet for a cooling medium, said mold sections confining together with said bottom part a hollow space for liquid metal and being separable from each other, said upper part having means for maintaining said sections in closed juxtaposition during the casting operation, and means for separating said sections after at least a skin on said liquid metal has been solidified so as to disengage the ingot formed by said solidification, said bottom part having means for removing the same laterally from said upper part together with said ingot, and means for retaining said ingot on said bottom part during transport, the number of said bottom parts exceeding the number of said upper parts so as to allow cooling of the ingot supported on a bottom part while the upper mold part used for casting said ingot cooperates with another bottom part.

3. A mold according to claim 1, wherein said hollow space confined by said mold sections and said bottom part has frusto-pyramidal form.

4. A mold according to claim 1, wherein said bottom part has a plane supporting surface for the ingot, said means for retaining said ingot on said bottom part com.- prising at least one recess formed in said bottom part and spaced from the outer edge of said bottom part on said surface for being filled with the ingot metal and for acting as retaining means for the ingot after separation of said bottom part and said mold sections.

References Cited in the file of this patent UNITED STATES PATENTS