US3688834A

US3688834A - Semi-continuous vertical casting mould for ingots

Info

Publication number: US3688834A
Application number: US209728A
Authority: US
Inventors: Frank E Wagstaff; William G Wagstaff; Paul H May
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-12-20
Filing date: 1971-12-20
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05

Abstract

An improved peripheral mould for the semi-continuous vertical casting of ingots, providing a compound disassembliable structure with internal fluid cooling. The mould constitutes an improvement over known art by providing a thickened casting surface to prevent thermal warpage and to allow steeply angled coolant dispersal holes which tend to provide more efficient and uniform cooling and combined with a particular input system maintain water in the mould structure upon failure of the coolant supply to prevent mould damage.

Description

United States Patent Wagstatf et a1.

[451 Sept. 5, 1972 [54] SEMI-CONTINUOUS VERTICAL CASTING MOULD FOR INGOTS [72] Inventors: Frank E. Wagstaff; William G. Wagstaff; Paul H. May, all of PO. Box 186, Spokane, Wash. 98112 [22] Filed: Dec. 20, 1971 [21] Appl. No.: 209,728

[52] US. Cl .....164/283 [51] Int. Cl. ..B22d 11/12 [58] Field of Search ..164/89, 283

[56] References Cited UNITED STATES PATENTS 2,414,269 l/l947 Nicholls 164/89 2,515,284 7/1950 Zeigler et a1 ..164/89 3,463,220 8/1969 Moritz 164/89 3,098,269 7/1963 Baier ..l64/283 Primary Examiner-J. Spencer Overholser Assistant Examiner-V. K. Rising Att0rneyKeith S. Bergman [57] ABSTRACT An improved peripheral mould for the semi-continuous vertical casting of ingots, providing a compound disassembliable structure with internal fluid cooling. The mould constitutes an improvement over known art by providing a thickened casting surface to prevent thermal warpage and to allow steeply angled coolant dispersal holes which tend to provide more efficient and uniform cooling and combined with a particular input system maintain water in the mould structure upon failure of the coolant supply to prevent mould damage.

4 Claims, 5 Drawing Figures PKIE'N'IEMEF smz v 3.688.834

sum 2 or 2 FRANK 5 WAGSTAFF, W/LL/AM a. WAGSMFF and Rs PAUL H MA),

SEMI-CONTINUOUS VERTICAL CASTING MOULD FOR INGOTS II. BACKGROUND OF INVENTION IIA. RELATED APPLICATIONS There are no applications directly related hereto now filed in any foreign countries but this invention does constitute an improvement over the general type of mould disclosed in our co-pending application Ser. No. 599,444, filed July 30, 1970 for Continuous Casting Mould.

IIB. FIELD OF INVENTION This invention relates generally to the field of peripheral, vertical casting moulds having fluid cooling through an internal chamber and more particularly to such moulds providing maximum heat transfer area and thermal stability.

IIC. DESCRIPTION OF PRIOR ART Metallic ingots, particularly of aluminum, have heretofore been cast in a semi-continuous vertical process by using a peripheral mould defining a horizontal cross-section of the ingot. The moulds, of necessity, are cooled, generally by water circulating through an internal chamber to thereafter impinge upon the ingot surface emerging from the mould to additionally aid solidification of the cast ingot. The general nature of such moulds is well known in the prior art and particular forms are set forth in our prior application heretofore referred to.

The form of such moulds has become somewhat standardized by reason of manufacturing practice and the vparticular necessities of an internal surface defining in a horizontal plane the periphery of the ingot to be cast. The moulds vertical extension is somewhat limited to alleviate sticking of the cast ingot after solidification of its surface, and allow immediate impingement of coolant to prevent undesirably physical changes in the ingot. Normally the interior of the mould is divided into two adjacent, concentric annular chambers-the outer chamber serving as a manifold for cooling fluid to disperse it through a dividing septum into an inner dispersal chamber where it serves its primary cooling function and from whence it is dispersed downwardly and inwardly to impinge upon the emerging moulded ingot surface to aid solidification of the cast material. The details of construction of such mould may vary considerably, but to this extent they are essentially similar.

In using such moulds various problems have been experienced which the instant invention seeks to remedy:

With use, the mould configuration tends to skew and its individual elements tend to warp, apparently largely by reason of semi-plastic flow of the mould material and internal stresses and strains caused by the thermal activities of the moulding process. If the skewing and warpage be not great, they sometimes may be corrected by bending and additional finishing, though if this be accomplished the life of the mould thereafter is not great. The instant invention seeks to alleviate this problem of change in mould configuration by providing a thicker inner or moulding surface. This thicker surface cooperating with the other mould parts prevents skewage by reason of its beam effect and prevents warpage apparently by faster, more efficient heat transfer which prevents crystalline structure change, plastic flow or similar problems.

The thicker interior casting wall also permits a more acute angling of fluid output channels to allow them to enter the upper portion of the inner water chamber and present a greater surface area for contact of mould and coolant which tends to provide a more efficient heat transfer for more efficient and uniform cooling of both mould and ingot.

In moulds of the prior art, problems of overheating upon interruption of coolant flow-have been common since the inner cooling chamber normally exhausts through fluid exit channels located in the lower portion of the chamber, so that if coolant flow be interrupted to the mould, the fluid in the inner chamber immediately drains to allow a possible overheating of the mould in the period of time necessary to correct or alleviate the problem. The instant invention provides the communication of fluid exit channels in the upper portion of the inner fluid chamber so that the inner chamber may not be drained by water flowing through the exit channels. Coolant level in the mould will therefore be at least at the level of the imput and if coolant cannot reverseflow through the imput channel; the coolant level may be above the imput level so that the inner cooling chamber will retain coolant upon imput failure and prevent overheating for some period to allow a reaction time to correct flowage difficulty or allow shutdown before damage is done to the mould.

III. SUMMARY OF INVENTION Our mould is of annular shape providing a vertical internal moulding surface defining the periphery of an ingot to be cast and having some outward extension to define an annular coolant chamber outwardly adjacent the moulding surface. The lowermost inwardlyfacing portion of the mould is provided with an annular coolant dispersal skirt communicating by plural spaced holes angling inwardly and upwardly to communicate with the inner surface of the water chamber in its upper part. The mould is formed with a separate releasably joined bottom element to allow for manufacturing and access to the coolant chamber for necessary cleaning. The annular coolant chamber is divided by a medial septum into an inner dispersal chamber and an outer, surrounding, manifold chamber with plural holes communicating through the septum to allow flow from the manifold to the coolant chamber. The septum itself is preferably mechanically joined to the bottom element so that it may be removed therewith to aid cleaning and its upper portion is provided with an appropriate gasket to provide a seal requiring coolant flowing from the manifold chamber to pass through the septum holes to enter the dispersal chamber.

An externally communicating orifice with associated fixture is provided to allow the input of pressurized fluid coolant into the manifold portion of the coolant chamber.

In providing such a mechanism it is:

A principal object of our invention to create a peripheral vertical casting mould having a substantially thickened inner casting surface to prevent mould warpage and skewage and extend the useful life of the mould.

A further object of our invention to provide such a mould with coolant exhaust channels communicating from an annular skirt in the lower inner portion of the mould upwardly and outwardly to the upper portion of the coolant chamber to maintain the coolant chamber full of fluid upon interruption of coolant flow.

A still further object of our invention to provide relatively small exhaust channels of relatively great surface area to increase the velocity of coolant flow therethrough to aid heat transfer and the efficiency of cooling, especially by disturbing steam formation immediately adjacent the channel defining mould walls.

A still further object of our invention to provide a mould that is of new, novel and improved design, of rugged and durable nature, of simple and economic manufacture and otherwise well adapted to the uses and purposes for which it is intended.

Other and further objects of our invention will appear from the following specification and accompanying drawings which form a part hereof. In carrying out the objects of our invention, however, it is to be remembered that its essential features are susceptible of change in design and structural arrangement with only one preferred and practical embodiment being illustrated in the accompanying drawings as required.

IV. BRIEF DESCRIPTION OF DRAWINGS In the accompanying drawings which form a part of this application and wherein like numbers of reference refer to similar parts throughout:

FIG. 1 is an isometrical surface view of a typical peripheral casting mould embodying the improvements of our invention.

FIG. 2 is a vertical cross-sectional view through the end part of the mould of FIG. 1 taken on the line 22 thereon in the direction indicated by the arrows.

FIG. 3 is a vertical cross-sectional view through the side of the mould of FIG. 1 taken on the line 3-3 thereon in the direction indicated by the arrows to show water level in the internal coolant chamber upon interruption of fluid flow.

FIG. 4 is an isometric view of a sectional piece of our mould showing the details of its construction.

FIG. 5 is an exploded isometric view of our invention showing the nature and relationship of its various elements.

V. DESCRIPTION OF THE PREFERRED EMBODIMENT The bottom opening mould structure of the drawings comprises upper moulding element and bottom element 11 releasably joined by fastening means 12 to define internal coolant chamber 13 divided into outer manifold chamber 36 and inner dispersal chamber 37 by septum 14.

Upper mould element 10 provides annular body 15 defining the vertical internal mould periphery by inner surface 16 of moulding wall 17. The element is generally milled from unitary metallic stock to define internal coolant chamber 13 in such fashion that the thickness of moulding wall 17 is quite substantial, approximating 1 inch in thickness normal to the moulding surface when the other body parts are configured as in the illustrations of FIGS. 2 and 3. This provides in the body a U-shaped beam-like structure that is especially resistant to skewing forces. Outwardly projecting lip 18 is provided for mounting the mould on a horizontal support in the fashion tradionally employed in present day ingot casting. The lower, inner portion of moulding wall 17 defines coolant dispersal skirt 19, configured to aid the flow of coolant fluid thereover to substantially uniformly impinge upon the peripheral surface of an exiting ingot to aid cooling of the cast product. The lower inner portion of moulding wall 17 is removed to form bottom ledge 20 adapted to receive the outer periphery of the bottom element.

Plural spaced dispersal channels 21 communicate from outer orifices 22 in the outer portion of bottom ledge 20 upwardly and inwardly to inner orifices 23 spaced along the upper inner surface of moulding wall 17 to communicate with the dispersal chamber. Normally the dispersal channels will be separated by some distance to provide webs of substantial dimension to cause sufficient rigidity in the lower portion of moulding wall 17 to prevent warping, especially such as would allow an uneven flow of coolant to cause a further skewing of mould or ingot according to the prior art and teachings of our prior patent application hereinbefore referred to. The relative size of the dispersal channels must be determined by known methods to provide appropriate cooling and allow exit of the input coolant with some velocity, preferably sufficient to disturb or destroy steam effects on the surface of the dispersal channel-defining walls to provide more efficient heat transfer and consequent cooling of the mould structure. The dispersal channels will normally be symmetrically and equally spaced to provide substantially equal cooling throughout the mould and to provide a substantially uniform curtain of coolant impinging upon the exiting ingot so that the cooling will be symmetrical and not cause skewing of mould or ingot or either in relation to the other. Corners may require some deviation from equal spacing but such corner distributions of coolant channels are known in the prior art.

Bottom element 11 is a flat annular structure of cross-sectional configuration illustrated in FIG. 2, et seq. It provides an upper inner surface adapted to fit against the lower surface of bottom ledge 20 and is of an appropriate configuration to extend about the entire bottom surface of the annular mould to enclose the coolant chamber. Medial annular septum groove 24 is provided to receive the lower edge of the septum and outer annular gasket groove 25 is provided to receive ring-type gasket 26 in appropriate position to seal the upper surface of bottom element 11 against the lower surface of the outer portion of upper element 10 in a water-tight joinder. Outwardly facing surface 27 of the bottom member is angled, as illustrated in the crosssectional views of FIGS. 2 and 3, to cooperate with the adjacent lower surfaces of the lower portion of bottom ledge 20 and skirt 19 to form coolant dispersing annulus or skirt 28 to substantially uniformly disperse coolant received from the plural dispersal channels upon the emerging surface of a cast ingot.

Fastening means 12 in this instance comprises headed bolts 29, communicating through plural spaced holes 30 in the bottom element to threadedly engage within plural cooperating threaded holes 31 in the lower portion of the upper element to releasably join the members, again as illustrated in the sectional diagrams of FIGS. 2 and 3. Other mechanical fastening means might serve a similar purpose, and pins have been used in similar moulds for commerce.

Septum 14 is formed from annular band-like element 32 of material sufficiently flexible to fit in its lower portion within septum groove 24 in bottom element 11. The joint between these members is substantially water tight and mechanically maintained by swagihg or other fastening means. The upper portion of element 32 carries gasket 33 fitting about the upper edge of the septum by means of groove 34. The vertical dimensioning of the septum and gasket are such that when positioned as illustrated in the cross-sections of FIGS. 2 and 3, the septum will divide internal coolant chamber 13 into outer manifold chamber 36 and inner dispersal chamber 37. The lower medial part of the septum is provided with a row of holes 35 at spaced distance from each other and from the lower edge of the septum. These holes 35 allow access of coolant from outer chamber 36 into inner chamber 37 from whence it might be dispersed through the dispersal channels. The number of holes and their size may vary according to known standards in the art to allow an appropriate flow of water to maintain the inner dispersal chamber 37 full and provide appropriate pressure of the fluid coolant through the dispersal channels to prevent formation of gas on the channel walls and provide an efficient cooling for the mould and emerging ingot. Preferably the holes are smaller than the dispersal channels to act as a strainer for debris because they are easier to clean than the dispersal channels.

Coolant fluid is supplied to outer manifold chamber 36 through input fixture 38 and input piping 39 from some external pressurized source not shown).

The use of our casting mould is substantially the same as that of similar moulds heretofore known. The function of the improvements, however, is to be particularly noted.

The thickened structure of moulding walls 17 prevents premature warpage and substantially prolongs the life of the mould. The instant mould is particularly adapted for use in the aluminum industry where such moulds are traditionally machined from cast aluminum stock. The reason that this mould does not warp and that its life is prolonged is not definitely known, but most probably the thicker wall accompanied by the particular position and configuration of dispersal channels provides a more uniform and more efficient transfer of heat through and away from the moulding surface which apparently substantially lessens or prevents deleterious changes in the structure of the mould material, especially by way of re-crystallization and semi-plastic flow. Heat distribution throughout the gross mass of the mould apparently is also more uniform to prevent deleterious changes in various parts of the mould caused by differential thermal gradients.

The condition of coolant in the mould upon stoppage of flow from the input source is illustrated in FIG. 3 of the drawings. With inner orifices 23 of the dispersal channels 21 in the upper portion of the inner surface of moulding wall 17, when coolant ceases to flow from the input source it will assume a level not below the lowermost surface of either the input orifice or dispersal channel orifice. lf fluid may not return through the input channel the level may be above the input orifice. Since either orifice is in the upper portion of the inner dispersal chamber, a substantial level of coolant will remain in the inner dispersal chamber upon any failure of pressurized input. This coolant will tend to provide additional cooling for the mould for sometime after failure of coolant input and this period of time will be sufficient to correct an accidental problem interrupting the flow to prevent damage to the mould during the casting process or allow stoppage of the moulding process. The moulds heretofore known generally had an orifice located near the bottom portion of the coolant chamber which allowed fluid to exit therefrom upon failure of the pressurized input.

It is further to be noted that the heavier structure of the moulding wall of our mould and beam-like character of the mould in general tend to aid in preventing or. lessening any skewing of the mould by physical stresses or strain.

It is further to be noted that if some of the holes in the septum become plugged with debris, the input chamber will tend to act as a manifold to tend to equalize flow through the remaining holes to maintain coolant supply.

The foregoing description of our invention is necessarily of a detailed nature so that a specific embodiment of it might be set forth as required, but it is to be understood that various modifications of detail, rearrangement and multiplication of parts may be resorted to without departing from its spirit, essence, or scope.

Having thusly described our invention, what we desire to protect by Letters Patent, and

What we claim is:

1. In a compound, bottom opening, liquid cooled mould for vertical semi-continuous casting, of the class having an annular body, with a vertical inner surface defining the vertical periphery of an ingot to be cast and an internal annular coolant chamber separated into an outer manifold chamber and an inwardly adjacent dispersal chamber by an annular band-like septum carried by an annular bottom element releasably joined to the body to enclose the water chamber, the sides of the annular bottom element cooperating with the body element to form an annular dispersal skirt to impinge coolant upon the surface of an emerging ingot, the invention comprising:

a relatively thickened moulding wall defining the periphery of the ingot to be cast with plural, relatively small, spaced coolant dispersal channels communicating from the annular dispersal skirt upwardly and inwardly with input orifices in the upper portion of the inner surface of the moulding wall defining the dispersal chamber.

2. The invention of claim 1 further characterized by plural spaced holes in the lower portion of the septum to allow fluid communicating between outer manifold chamber and inner dispersal chamber only therethrough, said holes being smaller in cross-section than the dispersal channels.

3. A compound, bottom opening, liquid mould for vertical semi-continuous casting of metals, comprising in combination:

an annular body element having a vertical inner surface defining the periphery of an ingot to be cast, the body having some size to partially define therein the top and sides of a water chamber and the lowermost inner portion thereof aiding in defining a coolant dispersal skirt to cause coolant to impinge upon the skirt surface of an ingot being cast;

a flat annular bottom element releasably positionable upon the body element to enclose the coolant chamber and having an outward edge cooperating with the body member to define an annular coolant dispersal skirt to direct coolant upon the exiting surface of an ingot, and carrying;

a band-like septum extending upwardly from the bottom member to communicate with the upper surface of the coolant chamber to divide the coolant chamber into an outer manifold chamber and an immediately inwardly adjacent dispersal chamber, the septum having plural spaced holes in the lower cross-section than the dispersal channels to act as' a filter therefore.

* l I I t

Claims

1. In a compound, bottom opening, liquid cooled mould for vertical semi-continuous casting, of the class having an annular body, with a vertical inner surface defining the vertical periphery of an ingot to be cast and an internal annular coolant chamber separated into an outer manifold chamber and an inwardly adjacent dispersal chamber by an annular band-like septum carried by an annular bottom element releasably joined to the body to enclose the water chamber, the sides of the annular bottom element cooperating with the body element to form an annular dispersal skirt to impinge coolant upon the surface of an emerging ingot, the invention comprising: a relatively thickened moulding wall defining the periphery of the ingot to be cast with plural, relatively small, spaced coolant dispersal channels communicating from the annular dispersal skirt upwardly and inwardly with input orifices in the upper portion of the inner surface of the moulding wall defining the dispersal chamber.

3. A compound, bottom opening, liquid mould for vertical semi-continuous casting of metals, comprising in combination: an annular body element having a vertical inner surface defining the periphery of an ingot to be cast, the body having some size to partially define therein the top and sides of a water chamber and the lowermost inner portion thereof aiding in defining a coolant dispersal skirt to cause coolant to impinge upon the skirt surface of an ingot being cast; a flat annular bottom element releasably positionable upon the body element to enclose the coolant chamber and having an outward edge cooperating with the body member to define an annular coolant dispersal skirt to direct coolant upon the exiting surface of an ingot, and carrying; a band-like septum extending upwardly from the bottom member to communicate with the upper surface of the coolant chamber to divide the coolant chamber into an outer manifold chamber and an immediately inwardly adjacent dispersal chamber, the septum having plural spaced holes in the lower portion thereof for passage of fluid from manifold chamber to dispersal chamber; a plurality of relatively small, spaced coolant dispersal channels communicating from the coolant dispersal skirt upwardly and inwardly to communicate with the upper portion of the coolant dispersal chamber; means of releasably fastening the bottom element to the body element; and means of supplying pressurized coolant fluid to the manifold chamber.

4. The invention of claim 3 further characterized by: the plural spaced holes in the septum being smaller in cross-section than the dispersal channels to act as a filter therefore.