US2479191A - Fluid cooled mold - Google Patents

Description

ug- 1949- E. R. WILLIAMS ET AL FLUID COOLED MOLD 5 Sheets-Sheet 1 Filed Feb. 15, 1945 fidwa rdzr. Waziams Kurt C Warmb'ez'n flxcllundquist Aug. 16, 1949. E. R. WILLIAMS ET AL, 2,479,191

FLUID GOOLED MOLD Filed Feb. 15, 1945 s Sheets-Sheet'Z 1 E i 1 i "r; I 54 T 1 E g1 46 3 "3:35 3 1 111.12" 42 I; V I O FELT/87110115 Edward 12. Williams 45 Kurt C.Wa.rmbe1;n AxeZLLmdq-uist E. R. WILLIAMS ET AL IAuLg. 16, 1949."

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Patented Aug. 16, 1949 Lundquist, Latrobe,

Engineering Company, ship comprised of Edward R.

Latrobe, Pa., a partner- Julia Lee Cox Williams Application February 15, 1945, Serial No. 577,950 3 Claims. (Cl. 22-144) This invention relates to a mold 'for the casting of metal and especially a mold designed for the casting of ingots or billets. The invention is applicable either to unit capacity molds wherein the mold cavity is filled with molten metal and the metal chilled while stationary within the cavity, or is, also applicable to the continuous casting of metal disclosed, for example, in prior patent to Edward R. Williams No. 2,079,644, granted May 11, 1937. n Molds of the type referred to comprise an inner sleeve or tubular element of any desired or preferred cross-sectional shape encased within a surrounding body with a space between the inner sleeve and the outer body for the passage of a cooling fluid. While the inner sleeve may be of any material and of any thickness suitable for the purpose, it is frequently desirable, especially when casting metals of high temperature, to use an inner sleeve of metal of high heat conductivity whose melting point may be lower than that of the metal being cast and to remove the heat from the solidifying ingot by the circulation of water along the outside of the inner sleeve at a velocity sufficient to prevent the tubular element or sleeve from being damaged by the molten metal. In such case it may be desirable that both the sleeve be relatively thin and the radial depth of the stream of water along the outer surface of the sleeve be relatively shallow, to provide effective heat transfer. In such apparatus, to obtain a high velocity of water flow, it is frequently found necessary to subject the outside of the sleeve to water pressure sufficient to bow or distort the sleeve inwardly against the metal being cast. Likewise, changing thermal condi tions within the sleeve itself during the pouring of molten metal against it, may cause'expansion and distortion of the sleeve. Such bowing and distortion is more pronounced as the length and cross-sectional area of the ingot cavity increases and in certain geometric shapes such as rectangular sections as compared with round, square, or other sections having greater mechanical strength. When bowing and distortion of the sleeve or tubular element occurs during the use of such molds a number of difficulties may be encountered; the sleeve or mold wall is altered in shape and size which may result in a change in velocity of Water flowand the surface of the walls of the sleeve become distorted or irregular which makes removal of the ingot more difficult, particularly in continuous casting. All of these factors and conditions increase the ob stacles of mold-design and construction, and the assignors to Williams Williams and present invention pertains to a mold structure designed to overcome or minimize these difficulties and enable molds of this kind to be more economically constructed and more efficiently used. One of the chief objects of this invention is to improve heat transfer efficiency by increasing the surface velocity of the cooling fluid along the outer surface of the mold wall or sleeve with-' out causing substantial deformation of the mold wall. We have observed that as the average ve locity of the cooling fluid increases, even beyond the velocity at which turbulent flow occurs, an increase in heat transfer takes place. This is apparently due to the fact that the zone of laminar or straight line flow of water very close to the outer surface of the mold wall is reduced in thickness as the average velocity of flow increases. The reduction in thickness of this zone of laminar flow causes a drop in the film resistance of this layer to heat transfer therethrough, with a consequent step-up in overall heat exchange between the molten metal inside the ingot cavity and the coolant. By the general means described, several forms of which are specifically illustrated herein, the mold wall is secured against deformation. In several of the embodiments of the inven-j tion herein illustrated, strengthening of the mold wall against deformation caused by fluid pressure or thermal expansion is obtained by tying the casting tube or mold wall into the outer body or casing firmly. v

The invention also provides a mold structure of the type referred to in which the construction of the outer casing and the manner of holding the sleeve within the casing lends itself to ease of manufacture, particularly in such machining operations as are necessary. I

Our invention may be more fully understood by reference to the 'accompanying drawings, in which: Fig. 1 is a transverse section of a water cooled mold of the seamless tube, and sectional casing type, and employing a stud type of reinforcing means for the wall of the tube between the ends or sides of the tube, the view being a section in the plane of line I-I of Fig. 2; V I Fig. 2 is a longitudinal section taken on the line and looking in the direction of the arrows II-II of Fig. 1;

Fig. 3 is a fragment taken on the line and look-'- ing in the direction of the arrows III-III of Fig. 1, showing more clearly a detail of the openended slot leading to a recess in the wall of the casing sector section with stem of a bolt, as a strengthening feature also facilitating assembly of the mold parts;

Fig. 4 is a plan of a modified form of streamlined stem contour for the stud portion disposed within the fiuid duct;

Fig. 4a is a perspective View of one segment and a portion of the casting tube of the assembly shown in Figs. 1 and 2, the axis of the mold being turned sideways;

Fig. 5 is a front elevation of a mold including a plurality of transverse sections with the tubular Portions in alignment, with the lower portion broken away to show a longitudinal portion in section of portions of the two lower sections;

Fig. 6 is a top plan of Fig. 5 partly broken away to show in transverse section a sector sectional portion of the sectional tube and casing in assembled relation with the liquid cooling duct therebetween;

Fig. 7 is an end elevation of one sector section of the sectional tubing for one transverse section of the mold;

Fig. 8 is a top plan of Fig. 7, showing the reinforcing ribs extending the full length of the tube between the end plates.

Fig. 9 is a view similar to Fig. 5 showing another modification;

Fig. 10 is a top plan similar to Fig. 6 but showing a modified form employing a continuous or seamless type tube, and sectional casing, but with integrally secured strengthening ribs extending between the sides and ends of the casing, with a space between its ends and the end plates integrally secured to the ends of the tube;

Fig. 11 is a front elevation of Fig. 10 more clearly showing the limited length of the ribs, as noted in description of Fig. 9;

Fig. 12 is a top plan of the seamless tube, and plate and strengthening ribs, with the end plate broken away, and showing a portion of the tube and certain ribs in transverse section; and

Fig. 13 is a transverse vertical section throughanother modification of the invention in which the sections are of short vertical height.

Referring first to Figs. 1, 2 and 3, the mold assembly comprises an outer shell or casing constituted of a multiple number of segments. Four of these segments are illustrated and are designated 2, 3, 4 and 5. Each segment is a quadrant of the entire assembly and each has a flange 5 projecting from the vertical edges thereof to enable the sections to be bolted together by the bolts indicated at 5a. The segments of the easing are also provided with top and bottom flanges designated 7 and 8 respectively.

When the segments are bolted together as shown in Fig. 1 they form within the interior thereof a passageway designated generally as 9. On the interior walls of the segment and extending in an axial direction at appropriate intervals are ribs I which may be either integral or attached. Because of the parts being made in segments, the machining of the interior of the shell may be readily accomplished, whereas if the shell were formed as an integral body, the accurate formation of the interior passageway with the ribs Ill would be difiicult. The meeting faces of the various sections are machined to a close fit and may be rendered water-tight by the tightening up of the bolts 6a, particularly if sealing compound or pipe dope is used on the abutting faces.

Both of the contacting face portions of each of two diagonally opposite segments, 1. e., 3 and in Fig. 1, may be provided with one or more side the outer shell,

T-slots or openings best shown in Figs. 3 and 4a, these slots being open on the face of the segments when the segments are taken apart, the pocket portions, designated I I are sufilciently large to accommodate a wrench while the slots 12 which are formed forwardly of the openings are adapted to receive a bolt as will be hereinafter more fully described.

Concentrically positioned in the passageway 9 is the casting tube or sleeve designated I3, and which is shown in Figs. 1 and 2 as being a seamless tube of rectangular cross section, but it may have any other appropriate shape. The tube I3 is shown as having four walls I3a, I3b, I30 and I3d. The sleeve rests against and is held tightly against the longitudinally extending ribs I 0 inthese ribs constituting spacers to hold the sleeve in spaced relation to the shell, thereby providing a substantially continuous fluid-circulating passage I4 between the sleeve and the outer casing, and at the same time these ribs provide a reinforcement for the exterior of the sleeve.

The sleeve is provided on each of its four walls with one or more bolts or studs I5 fused, welded, soldered, tapped into, or otherwise secured to the sleeve. These bolts are accurately positioned to pass through the slots I2 with their outer ends projecting into the openings II so that nuts I B may be applied to the outer ends of these studs and the nuts tightened up to firmly clamp the sleeve in position. It is to accommodate a wrench to turn the nuts I6 that the pocket portions II are made as large as they are. In lieu of using bolts having round shanks, the bolts may be of a modified shape, as shown for example in Fig. 4, in which the portion of the bolt I5 which traverses the water passage is streamlined or oval, the long axis being set lengthwise of the flow of water.

In makin the assembly, the two segments 3 and 5 are first brought into position diagonally opposite each other around the sleeve and the bolts are engaged in the slots I2 in the manner above indicated. At this time the segments 2 and 4 are not in place so that a wrench may be inserted into the openings II and turn the nuts I6 to put the studs or bolts I 5 under tension. After the two quadrants 3 and 5 have been thus assembled with the tube, the quadrants 2 and 4 are brought into place and the bolts 6a inserted and tightened.

In addition to having the studs I5, each end of the seamless casting tube I3 is provided with an end plate I 7 at each end thereof, the end plate having a central aperture of the shape and contour of the casting tube, so that the casting tube is snugly fitted therein and the end plates are soldered, brazed, welded, or otherwise integrally secured to the casting tube. The length of the tube section I3 and the distance between the two end plates I1 is Just such that the segments of the outer shell or casing may be fitted into place with the end plates I'I extending over the end faces of the several quadrants or segments.

Formed in the end face of each quadrant or segment is a channel I9, the channel portions of the several quadrants forming a continuous annular trough or header in the completed assembly at each end thereof and the quadrants themselves have the inner portions of the end faces thereof shorter than the over-all length of the quadrants whereby to provide a passage 20 at each end of the assembly for the flow of Water between the annular channels l9 and the passage l4. The channel or header 19 should be of sufficient cross-sectional area for the volume of cooling fluid used to provideapproximately uniform pressure distribution therein and flow of fluid through the passage l4.

A fluid circulating pipe 2| is provided in the top of one of the quadrants and terminates in the channel I9, while a similar pipe 22 is connected into another of the quadrants at the opposite end communicating with the channel 19, one of these pipes servin as a fluid inlet pipe, and the other as a fluid outlet pipe. Hence, assuming 2! to be the inlet pipe, water or other cooling fluid enters the top of the assembly under the end plate I'l, fillingthe channel 19, flowing through the passage 20 into the cooling space M, flowing down around theexterior of the mold-shell I3, escapingthrough the passage 20 at the lower end of the water space, and then out the pipe 22. A plurality of inlet and outlet pipes may be used.

The assembly is completed by topand bottom plates 23 which are bolted in place by bolts '24,

these bolts passing through the plate 23, through the end plates I1, and into the flanges I or 8 as the case may be.

In case it is desired to superimpose several of these segments to form a longer mold, the plates 23 are omitted between abutting assemblies. In Fig. 5, for example, we have shown several superimposed sections, slightly different from the ones shown in Figs. 1 and 2, but the placing of the sections shownin Figs. 1 and 2 in end-toend relation, as illustrated in Fig. 5 is contemplated by our invention.

Also, for purposes of illustration, we have shown only one bolt I5 on each of the four faces of the mold. Depending upon the thinness of the walLthe length of the tube, and other factors, the number of bolts or studs I5 may be increased. Normally there would be more than a single stud 0r bolt on a side. With a very thin casting tube they might be placed along the tube one be:- low the other at quite close intervals.

f With the assembly thus described, the tubular casting sleeve I3 is supported by the ribs [0, against outward pressure while the studs l5 are put under tension and resist the tendency of the walls to bow inwardly toward the longitudinal axis of the mold.

By reason of the shell of the assembly being made in quadrants with the slotted opening on two faces of each of two diagonally opposite quadrants, the assembling of the mold is made possible. All of the quadrants constituting the outer shell or body are, except for the presence of the openings l l in two of the quadrants, identical,so that the quadrants can be economically cast and the machining, if necessary or the quadrants can be accomplished at minimum expense,

In the modification shown in Figs. 5, 6, 7, and 8', the general construction is much like that de-. scribed in connection with Figs. 1 to 4 inclusive, but insteadof the inner sleeve or casting tube being seamless, it is illustrated as being made up also of segments, preferably quadrants, so that each quadrant of a mold section assembly may be completely formed and put together, and then the several quadrants brought together to form a complete section.

In these figures the mold segments or quadrants are of the same general shape as shown in Figs. 1 and 2. They are designated generally as 30. They are provided with laterally projecting flange portions 33 to enable them to be se 6 curedtogether by bolts 34. The abutting faces of the sections are machined to a smooth fit. The segments also have upper and lower flanges 35 and 36 respectively. The segments when put together define the central passageway 38 and they are provided with ribs 39 similar to the ribs E0 of Fig. 1. Each of the segments is also provided with an upper and lower water channel 40 which is spaced outwardly from the central passageway 38.

, Set into each segment is a tube section of the shape bestshown in Figs. '7 and 8. Each-tube section has a wall portion 4! which is illustrated in Figs. 7 and .8 as being a right-angle. Along each edge of the wall portion 4! is an outwardly turned flange 42. At the top and bottom of the side plate is an end plate portion 43. The length or vertical height of the wall portion 41 is such that the end plate portions 43 fit over and form a seal against the flat end surfaces of the segments 30in which they are mounted. Each of the segments 30 is recessedalong each of its vertical edge faces, these recesses serving to receive the flanges 4'2 of the respective sleeve portions. Screws 44 passing through the flanges 42 into the body of the segments serve tosecure the segments in place, or the flanges may be secured to the segments by brazing or other means. Each inner tube segment is thus secured to its outer body segment with an intervening water passage 45 between the inner sleeve portion and the outer body portion. This water space communicates with the channel portion 40 as clearly shown in Fig. 5. Pipes 46" are provided for circulating water into or circulating water' from the channels 40 so that a stream of cooling water may be circulated in thelwater space 45.

This arrangement enables segments of the body and portions of the inner sleeve to be identical in construction. The parts are readily accessible for machining and finishing operations. Each sleeve portion is assembled to its corresponding body portion and then the several body.

portions or segments are bolted together forming the complete assembly. All parts are accurately machined so that there are no crevices, and the outer surfaces of the end plates43 are smooth so that assembly end plates 41 may be used or so that one segment may be. bolted on top of another as shown in Fig. 5, in either case making a tight joint and flush mold surface.

In the modification shown in Figs. 9, 10, 11 and 12 the construction is .a modification of the construction shownin'Figs, 5 and 6, except that in this embodiment the inner sleeve or casting tube is integral instead of being made in sections diprojecting flanges 5| so that the quadrants may vided vertically. In this modification also the outer body is made up of several segments or quadrants, each designated generally as 50. The vertical edges of the quadrants have outwardly be secured together by bolts, as shown. The abutting'vertical faces of the quadrants are machined to, make a water-tight joint. Each quadrant is provided with a top flange portion 53 and a lower flangeportion 54. As in the other forms, the segments or quadrants when secured together form a central passageway 55 and ribs 56 preferably provided on the interior vertical surfaces of the quadrants similar to the ribs ll] of Fig. l.

The inner sleeve or casting tube is of the same general cross-sectional shape as the passageway 55, but the overall dimension is slightlysmaller. This inner sleeve or casting tube comprises an integral seamless tubesection 51. About midway between each of the four faces thereof and on'the exterior thereof are laterally projecting vertical fins 58. These fins, which may be integrally secured to the tube by soldering, brazing, or otherwise, are positioned to extend between the abutting faces of the quadrants B, and one of the faces on two of the quadrants is recessed as shown in Fig. to receive these fins while the third segment, which in Fig. 10 is the lower righthand segment, has recesses on two of the vertical edge faces to receive the other two flanges on the casting tube, while the fourth segment or quadrant is not recessed. This arrangement is for purposes of assembly, inasmuch as the'lower right-hand segment or quadrant is first attached to the casting tube and then the lower left-hand segment is brought into place and the attachment made, after which the upper left-hand segment is brought into the assembly. Thus all of the screws 59 which secure the flanges to the quadrants can be applied and tightened after which the upper right-hand quadrant of Fig. 10 isfinally joined into the assembly.

The casting tube 57 as shown in Figs. 11 and 12 is provided with upper and lower end plates 60,

and the length of the casting tube 51 is such that these end plates 60 extend over and forward against the end faces of the quadrants so that they may be bolted thereto as in the other modifications.

A water-circulating passage BI is provided around the outside of the tube 51 and the inside of the outer body while the ribs 56 support and reinforce the casting tube as do also the flanges 58. Each quadrant is provided with an upper and lower channel portion 62, these channel portions providing a continuous passage for inflowing or outgoing water or other cooling fluid, and pipes 63 open into these channels at the top and bottom of each assembly. Several of the mold units may be arranged in superposed relation as clearly shown in Fig. 9. Water flow may be arranged either in series through the units or each unit may be connected separately to inlet and outlet lines.

In all of the modifications described, which are merely typical embodiments of our invention, the outer shell is made of segments or quadrants for ease and economy in machining and assembling. Provision is made for securing the sleeve or casting tube into the assembly, the arrangement being such that the casting tube and mold body segments can be separately formed and machined with a minimum of difiiculty. In all of the embodiments the casting tube is secured to the segments by means which is firmly attached to the segment so as to hold the walls of the casting tube against bowing inwardly, as well as cooperating with the ribs It or 56 in supporting the tube from bowing outwardly. -In other words, the securing means for the tube intermediate the ends of the tube may act either in tension or in compression, and the end plates on the tube sections cooperate with the intermediate securing means to support and reinforce the tube sections. The

tube sections may be metallic or non-metallic,'

and may be quite thin or of any preferred thickness, depending upon the conditions under which the mold is used.

In the modification shown in Fig. 13 the inner sleeve or casting tube, designated 70, is formed as a continuous body with no vertical joint, and it is provided with end flanges H and I2 fitting over the top and bottom 0f the housing 13 which is of the general form hereinbefore described,

but which may, if desired, be made in only two segments. The overall height of the section shown in Fig. 13 is a matter of relatively few inches so that there is no need for tying the sleeve into the housing intermediate its ends, the flanges H and 12 serving to tie the tube into the housing. The distance between the water inlet and the water outlet is also such that no very high pressure differential is required to force the water through the fluid-circulating space 14. A number of these units are put in end to end relation in the manner indicated in Fig. 9 to form a complete mold. In this modification the use of short sections with the flanges 1| serves to make the casting tube sufliciently rigid, eliminating the need for anchorage intermediate the ends. 7

The thickness of stream of cooling fluid is preferably relatively thin but this may be determined also from operating conditions. Generally, however, we have discovered that the overall heat transfer from molten metal to cooling fluid is markedly increased by an increase in velocity along the outer surface of the mold wall even above the velocity at which turbulent flow occurs.

While we have illustrated and described certain embodiments of our invention, these are merely illustrative and various changes and modifications may be made therein within the contemplation of our invention.

We claim:

1. A fluid-cooled mold comprising an outer body having a central passageway therethrough, a casting tube concentrically positioned in the passageway conforming in cross-section to the cross-section of the passageway but sufliciently smaller than the interior of the passageway to provide a space between the said tube and the body for the circulation of cooling fluid about the tube, and means secured to the tube intermediate its ends and at various points around its periphery and secured also to the body for positioning the tube in the body and resisting radial strains inwardly and outwardly against the walls of the tube, the body being divided longitudinally into a number of abutting sections, the abutting faces of said sections being contoured to receive said positioning and holding means for the tube.

2. A fluid-cooled mold comprising an outer body having a central passageway therethrough, a casting tube concentrically positioned in the passageway conforming in cross-section to the cross-section of the passageway but sufficiently smaller than the interior of the passageway to provide a space between the said tube and the body for the circulation of cooling fluid about the tube, and means secured to the tube intermediate its ends and at various points around its periphery and secured also to the body for positioning the tube in the body and resisting radial strains inwardly and outwardly against the walls of the tube, the body being divided longitudinally into a number of abutting sections, some of the abutting faces of said sections having cavities into which the said tube-holding means project and are secured.

3. A mold assembly comprising a plurality of like transverse sections secured together in endto-end relation, each section comprising an outer body portion joined to the body portions of ad- J'acent sections and formed of a plurality oflongitudinally-extending quadrants, the said body having a central passageway therethrough,

a casting tube in the body of each section concentrically arranged in the passageway and spaced inwardly from the body whereby to provide a space for the circulation of cooling fluid outside the tube and within the body, the tubes of the several sections abutting in aligned endto-end relation, means secured to the tube of each section intermediate its ends and at various points around the periphery of the tube, and also secured to the body along the abutting faces of said quadrants for anchoring the tube in the body, and means for circulating fluid through the fluid-circulating space of each section of the assembly.

EDWARD R. WILLIAMS.

KURT C. WARMBEIN.

AXEL LUNDQUIST.

REFERENCES CITED The following references are of record in the file of this patent:

5 UNITED STATES PATENTS Number Name Date 363,828 Hinsdale May 31, 18.87 1,018,906 Hibbard Feb. 27, 1912 in 1,070,106 Bossinger Aug. 12, 1913 1,888,913 Erichsen Nov. 22, 1932 1,936,280 Williams Nov. 21, 1933 1,988,425 Sumey Jan. 15, 1935 2,079,644 Williams May 11, 1937 [5 2,347,413 Hopkins Apr. 25, 1944 2,357,780 Mueller Sept. '5, 1944

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