US3885617A

US3885617A - DC casting mold assembly

Info

Publication number: US3885617A
Application number: US365835A
Authority: US
Inventors: John J Foye
Original assignee: Kaiser Aluminum and Chemical Corp
Current assignee: Kaiser Aluminum and Chemical Corp
Priority date: 1972-06-14
Filing date: 1973-06-01
Publication date: 1975-05-27
Anticipated expiration: 1992-05-27

Abstract

A readily changeable DC mold assembly comprising a tubular flanged mold, a coolant jacket and preferably a quick-release connecting means to urge the mold flange into engagement with the water jacket. A resilient, rubber-like gasket material is disposed between the portions of the water jacket and the mold flange to create a water-tight seal therebetween. A spacer means is disposed between the baffle member and the tubular portion of the mold to positively position the mold body.

Description

United States Patent [1 1 Foye DC CASTING MOLD ASSEMBLY [75] Inventor: John J. Foye, Livermore, Calif.

[73] Assignee: Kaiser Aluminum & Chemical Corporation, Oakland, Calif.

22 Filed: June 1,1973

[21] Appl.No.:365,835

Related U.S. Application Data [63] Continuation-impart of Ser. No. 262,510, June I4.

1972, abandoned.

[52] U.S. Cl. 164/283 [5|] Int. Cl 322d 11/12 [58] Field of Search l64/82, 283

{56] References Cited UNITED STATES PATENTS 2,862,265 12/1958 Vaughn et al. 164/283 M 3,059,295 l0/l962 Vosskuehler 164/283 M 3,749.52 7/l973 Dore et al l64/283 FOREIGN PATENTS OR APPLICATIONS 1,054,090 l0/l953 France l64/283 M [ll] 3,885,617 5451 May 27, 1975 867,]48 2/1953 Germany 164/283 M 8l3.755 9/l95l Germany v. 164/283 M 835,790 4/1952 Germany Primary ExaminerFrancis S. Husar Assistant Examiner-V. K. Rising Attorney, Agent. or Firm-Paul E. Calrow; Edward J Lynch [57] ABSTRACT A readily changeable DC mold assembly comprising a tubular flanged mold, a coolant jacket and preferably a quick-release connecting means to urge the mold flange into engagement with the water jacket. A resilient, rubber-like gasket material is disposed between the portions of the water jacket and the mold flange to create a water-tight seal therebetween. A spacer means is disposed between the baffle member and the tubular portion of the mold to positively position the mold body.

13 Claims, 7 Drawing Figures SHEET FII3 .EI

FATE N TEU 2 1915' SHEET .HIH lrli. k J M Illl 5 DC CASTING MOLD ASSEMBLY RELATED APPLICATIONS This application is a continuation-in-part of patent application Ser. No. 262,5 l0, filed June 14. I972 now abandoned.

BACKGROUND OF THE INVENTION The invention relates to the continuous or semicontinuous DC (direct chill) casting of metal, particularly light metals, such as aluminum. The DC casting of light metals is a well-known process and has been commercially practiced for many years. Initially, the molds were of simple design and comprised an open-ended tubular mold body provided with a flange portion extending out radially from the feed end of the mold from which the mold was supported. During the casting operation, the exterior of the mold body and the emerging ingot were flooded with coolant from sprays positioned concentrically with the mold. The cooling water, which is usually recycled in DC casting operations, carries considerable quantities of sediment which can partially or completely block coolant sprays. On those areas of the mold body where coolant flow is reduced due to spray blockage, the resultant temperature increase of the mold wall thins out the lubricant which detrimentally affects the surfaces of the cast ingot. If the coolant flow is severely reduced or stopped over a particular area of the mold body, the molten metal in the mold can melt completely through the mold body and flow into the casting pit. The surface quality of the ingots formed with the simple molds was very often poor because of the unequal distribution of coolant around the periphery of the mold and the emerging ingot. Moreover, the operational life of the tubular flanged molds was relatively short. Water jacketed mold assemblies were subsequently developed to eliminate the possibility of melting the mold and also provide for a more dimensionally stable mold during casting. However, due to the low velocity of water adjacent the water-jacketed mold surfaces, the heat transfer rates between the mold and liquid was low. The low velocity water also allowed the formation of scale on the outer surfaces of the mold, and frequently, the formation of gas on the surfaces which further impedes heat transfer. To provide more uniform and higher heat transfer rates, baffles were positioned concentrically with the tubular moid body to increase the water velocity adjacent the mold surfaces and to thereby minimize scale buildup and gas film formation. The baffle was usually made integral with either the water jacket or mold requiring extensive, complicated machining and considerably increasing the cost of the mold assembly. The water-jacketed molds were characterized by a much longer operational life because the assemblies were more rugged and less susceptible to thermal distortions. However, changing a mold with a water jacket due to normal wear or to change mold size (either length or diameter) was a very difficult and timeconsuming task because the entire mold assembly had to be removed including the water jacket. This required the disconnecting of water lines. lubrication lines, and the like. With horizontal continuous DC casting, mold changes are relatively infrequent, and thus the downtime for mold changes is not signifcant compared with casting time. in the case of semicontinuous vertical DC casting, molds are frequently changed, and the downtime for mold changes is very high compared with casting time. With the advent of level-fed reservoir top molds, sometimes referred to as heat insulated molds or hot top molds, described and claimed in US. Pat. No. 3,494,410, wherein the molten metal level in the reservoir above the chill mold is maintained at approximately the same level as in the feeding trough, mold changing became a more difficult and time-consuming task.

The water jacket and mold body members of the prior art mold assemblies were characteristically joined through screwor bolt-type connectors. Due to the relatively great forces generated by these connectors to effect a water-tight seal between the members, the mold body frequently became deformed requiring early replacement of the mold.

The mold bodies for jacketed mold assemblies generally were quite expensive due to the machining required for various lubrication and cooling conduits which were usually included in the mold body.

Against this background, the present invention was developed.

SUMMARY The present invention provides an improved DC mold assembly, particularly useful in the DC casting of light metals, such as aluminum. The mold body of the assembly of the present invention can be quickly replaced when necessary due to normal wear or due to the desire to change mold diameter or mold length and allows the interior surfaces of the mold assembly to be quickly exposed for removal of buildup on the mold surfaces or blockage of coolant passageways. The mold assembly of the present invention comprises a readily changeable, open-ended tubular mold body provided with an upper or flange portion which extends out radially from the feed end of the mold. The flange portion of the mold body is supported on the vertically extending leg of a coolant jacket which is positioned concentrically with the mold body and forms a coolant chamber therewith. The horizontally disposed leg of the coolant jacket supports a vertically extending baffle member which is concentric to the mold body and spaced therefrom. At least one spacing member is provided between the baffle member and the mold body to maintain a predetermined spatial relationship therebetween and to positively position the mold body. A resilient, rubber-like gasket material is provided between the mold flange and the vertically extending leg of the water jacket. A readily disengageable and engageable connecting means urge the flange portion of the mold into a soft, water-tight sealing engagement with the water jacket leg. The spacing member provides the necessary positive positioning of the mold body. To replace the mold body, the connecting means are disengaged, the mold body is removed, and, if mold length or diameter is to be changed, the baffle member is also removed. The new baffle member and a new mold body are positioned, and the connecting means re-engaged. Because the water jacket remains in position and is relatively permanent, it is unnecessary to remove the coolant and lubricant lines connected thereto. The mold of the present mold assembly is of relatively simple design which does not require the extensive and complicated machining required by the prior art waterjacketed molds.

DESCRIPTION OF THE DRAWINGS FIG. I is a side view partially sectioned ofa mold assembly of the present invention.

FIGS. 2 and 3 are cross-sectional views of embodiments of the present invention in which the mold body dimensions are smaller than that shown in FIG. 1.

FIG. 4 is an exploded side view partially sectioned view of the mold assembly shown in FIG. I and illustrates the method of assembly.

FIG. 5 is a perspective view of another embodiment of the present invention.

FIG. 6 is a cross-sectional view of another embodiment of the present invention.

FIG. 7 is a cross-sectional view of the embodiment shown in FIG. I wherein the spacing member is formed integral with the mold and is seated in a recess provided in the baffle member.

In the drawings, all corresponding parts are numbered the same.

DETAILED DESCRIPTION OF THE INVENTION With reference to FIG. I, the casting mold assembly of the present invention comprises an open-ended tubular mold body 10 provided with a flange portion 11, the inner surfaces of the mold body I0 defining the mold bore 12. The mold is formed of a highly heatconductive material, such as aluminum or copper, A generally L-shaped coolant jacket 13 defines a coolant chamber I4 with said mold and is adapted to maintain a body of coolant in contact with the outer surfaces of the mold body 10. The vertically extending leg 15 of the coolant jacket supports the mold through flange portion 11. Preferably, the horizontally extending leg 16 of the waterjacket is provided with a shoulder or re cess 17 adapted to seat and support a separate, vertically extending baffle member 18 which is positioned concentrically with the mold body 10, and in this case, the shoulder 17 and the contacting surfaces of the baffle member 18 should be machined to close tolerances to prevent or minimize coolant leakage. If no mold size changes are contemplated, the baffle member 18 can be made integral with the leg 16 of the water jacket. The coolant jacket 13 is rigidly fixed in a suitable man ner to a support base, such as a table top (not shown). At least one spacer means 19 is situated between the mold body 10 and the baffle member 18 to positively position the mold body I0 and to maintain the spatial relationship of the mold body 10 with respect to the baffle member 18 to thereby maintain the coolant velocity in the conduit 20 defined by these two members within desired limits to maintain proper uniform heat transfer rates. Preferably, the spacer means is formed integral with the baffle member 18 and machined to close tolerance for interflt with the recess 21 provided on the outer surfaces of mold body 10 as shown in the drawing. However, the spacer means may be a separate member or formed integral with mold body It] as shown in FIG. 7. Preferably, the spacer means 19 is a projecting ridge on the baffle member 18 and is provided with a plurality of coolant passageways 22 which direct coolant to impinge on the surface of the emerging ingot.

The upper face of the vertically extending leg 15 of the water jacket 13 is provided with a groove 31 adapted to receive a resilient, rubber-like O-ring 32. Preferably, the material of O-ring 31 is a natural rubher, elastomer or equivalent material having a hardness of about 25-80, preferably about 3060 as measured with a Shore Durometer to effect a soft, water-tight seal between the mold flange 11 and the water jacket leg I5. Clamping means 33 urge the mold flange II into a water-tight, soft sealing engagement with the upper surface 30 of the water jacket leg I5. Preferably, the clamping means 33 are of a quick-release type and effects a clamping force of less than about 500 pounds between the mold flange and water jacket leg. A suitable connector is Model No. 2 Link-Lock sold by the Simmons Fastener Corporation, Albany, NY. As shown in the Figure, one element 34 of the clamping means 33 is fixedly attached to clamping ring 35 which is utilized to urge the mold flange into a soft-sealing engagement with the water jacket. However, if desired, one element 34 ofthe connecting means may be affixed to the upper surface of the mold flange 35. Coolant, usually water, is introduced into coolant chamber I4 through conduit 27.

A lubricant passageway 40 passes through the upper leg 15 of the water jacket. Passageway 40 is coaxial with lubricant conduit 41 located in the mold flange and is in fluid communication therewith to thereby pass lubricant to the groove 42 provided in the upper surfaces of the mold flange II. Lubricant is introduced into passageway 40 usually under pressure from conduit 45. A lubricant seal 46 minimizes lubricant leakage between the flange and coolantjacket leg 15, Positioning means, such as locating pin 50 and cavity 51, which is adapted to receive the locating pin, position the mold body with respect to the water jacket. This assures alignment of the

lubricant passageways

40 and 41.

In the embodiment shown in FIG. 2, the water jacket 13 is essentially the water jacket shown in FIG I, but the mold body 10 has a smaller diameter than that shown in FIG. 1. The baffle member I8 has been replaced to compensate for the smaller diameter mold bore. In FIG. 3, the mold length is shortened in comparison with the mold length shown in FIG. I. The baffle member 18 has also been changed to compensate for the different size mold. The baffle member 18 usually must be changed each time the mold diameter or mold length is changed to maintain the velocity of coolant in the conduit 20 at the desired levels, and to provide a properly positioned point of impingement for the coolant streams.

FIG. 4 is an exploded perspective view of the mold assembly and generally illustrates the method in which the mold is installed or disassembled. The coolant jacket 13, which is usually rigidly fixed to a support base (not shown), is relatively permanent. To disassemble the assembly, the connecting means 33 are disengaged and the mold l0 and, if a different size mold is to be inserted, also the baffle member 18, are lifted out of the assembly. To reassemble, the new baffle member 18, if any, and a new mold I0 are merely placed into position and the connecting means reengaged Whereas the prior art jacketed molds required up to an hour or more for replacement by skilled personnel, such as millwrights, pipefitters and the like, the mold assembly of the present invention can be replaced in a matter of about a minute by casting station operators. Moreover, the mold assembly of the present invention allows for the rapid exposure of the interior portions of the mold assembly for removal of surface buildup and obstructions.

FIG. 5 is a perspective view of a level-fed reservoir top mold. The feed trough is generally shown at 60 with trough extension 61 which allows molten metal to flow into the reservoir top generally indicated at 62. The reservoir top 62 comprises a cylindrical refractory member 63 fonned of a suitable material, such as an asbestos-silica composition which is sold under the name Marinite. Usually, refractory cylinder 63 is made up of a plurality of Marinite rings bonded together by a suitable refractory adhesive. Means (not shown) are usually provided to urge the reservoir top 62 into engagement with the mold to prevent molten metal leakage therebetween.

Illustrated in FIG. 6 is a further embodiment of the present invention which is primarily directed to horizontal DC casting. The mold assembly shown generally comprises a tubular mold body 10 which has a flange portion 11 at the end of the mold body 10. Associated with the mold body 10 is a water jacket 13 comprising a first extended portion 15 which is generally concentric with the mold body 10 and a second extended portion 16 generally perpendicular to said first portion and generally defining a coolant chamber 14 with baffle member 18. Conduit 23 is provided between baffle member 18 and extended portion 15 to direct a stream of high velocity coolant at the junction of the mold body 10 and mold flange 11 so as to effect a high heat transfer rate in that area and then through

conduits

20 and 22 to spray onto the emerging ingot. The conduit 23 can be a continuous slot or can be series of apertures. Spacing member 19, which is shown as being integral with baffle member 18, is provided to positively position the mold body with respect to the baffle member. An upper surface of member 15 is provided with a groove or recess 31 which is adapted to receive a resilient, rubber-like O-ring 32. Collar 35 is positioned adjacent the extreme face of member 15 and flange I1 and suitably provided with grooves 70 and 71 adapted to receive resilient, rubber-like O-

rings

72 and 7,3. Suitable means, such as screw member 74, are provided to engage the collar with the mold flange and waterjacket and urge these members into a water-tight sealing engagement. The collar 35 is provided with a shoulder 75 to engage the orifice plate 80. Connecting means 82 are provided to urge the entire mold assembly into, and in particular orifice plate 80, a sealing engagement with plate 83 of the refractory lined molten metal trough 84. Lubricant is introduced through connection 76 in collar 35 and is fed to the surface of the mold flange 11 through conduit 75. A suitable porous gasket 77 formed of refractory material, such as Fiberfrax, is provided on the upper surface of the mold flange so as to provide a means for transporting lubricant from the conduit 75 to the innermost surface 12 of the mold body. Other means, such as suitable lubrication gaps, can also be employed.

FIG. 7 is a partial cross-sectional view of the embodiment shown in FIG. I and generally is the same except that the spacing member 19' is formed integral with the mold body 10 and that the spacing member 19' is seated into recess 21' provided in the surface of baffle member 18.

As is evident from the above discussion, the tubular flange mold described is relatively simple in design, and thus relatively inexpensive to make. Essentially all coolant and lubricant conduits are in other members of the mold assembly not the mold body. Because of the simple mold design which requires relatively little machining, it is frequently less expensive to discard a used mold and replace it with a new one rather than to try to refurbish a used mold.

Although the above discussion and drawings are directed to circular molds, the present invention is generally applicable to both square and rectangular molds or molds of any shape. Moreover, it is obvious that various modifications and improvements can be made without departing from the spirit of the present invention and the scope of the appended claims.

What is claimed is:

l. A DC mold assembly for casting light metals which allows for the rapid change of the mold body comprising in combination a. an open-ended tubular mold body provided with a flange extending out radially from the feed end of the mold body and provided with at least one recess in the outer surface of the mold body;

b. a coolant jacket comprising a first extending leg generally concentric with the mold body, a second extending leg generally perpendicular to the first extending leg and a baffle member disposed between the first extending leg and the mold body, the mating surfaces of the first extending leg and the mold flange being adapted to receive a coolantsealing gasket;

c. at least one spacing member extending inwardly from the baffle member and seated in the recess provided in the outer surface of the mold body to thereby positively position radially and axially the mold body with respect to the baffle member and define a plurality of conduits which allow the pas sage of coolant from the conduit defined by the baffle member and the mold body to the surface of an emerging ingot during casting;

d. a resilient, rubber-like gasket provided between the mating surfaces of the first extending leg of the coolant jacket and the mold flange; and

e. means to urge the mold flange into a water-tight engagement with the first extending leg of the coolant jacket.

2. The mold assembly of claim 1 where said spacing member is a projecting ridge formed integral with said baffle member and is provided with a plurality of coolant carrying passageways.

3. The mold assembly of claim 1 comprising a gasket material having a durometer hardness from about 25-80.

4. The mold assembly of claim 1 wherein said gasket material is in the form of an O-ring.

5. The mold assembly of claim 4 wherein the upper surface of vertically extending leg of said coolant jacket is provided with a recess adapted to receive said O-ring.

6. The mold assembly of claim 1 wherein said mold flange is urged into water-tight engagement with said coolant jacket with a force less than 500 pounds.

7. The mold assembly of claim 4 wherein said gasket material has a durometer hardness from about 30-60.

8. The mold assembly of claim 1 wherein said urging means includes a collar positioned on the upper surface of said mold flange.

9. The mold assembly of claim 1 wherein said baffle member is a separate member and is seated and supported in a recess provided in said horizontally dis' posed portion of said coolant jacket.

10. The mold assembly of claim 1 provided with sec ond conduit means in fluid communication with the coolant chamber defined by the mold flange. the first and second extending legs of the coolant jacket and the baffle member to direct coolant from said chamber onto the outer surface of the mold body in the area of the junction of the mold flange and mold body so as to maintain a high heat transfer rate in said area 11. A DC mold assembly for castin; light metals comprising in combination a. an open-ended tubular mold body provided with a flange extending out radially from the feed end of said mold body and provided with at least one recess in the outer surface thereof;

b. a coolant jacket comprising a first extending leg generally concentric with the mold body, a second extending leg generally perpendicular to the first extending leg and a baffle member disposed between the first extending leg and the mold body, the mating surfaces of the first extending leg and the mold flange adapted to receive a coolant sealing gasket;

c. at least one spacing member extending inwardly from said baffle member and seated in the recess provided in the outer surface of the mold body to thereby positively position radially and axially the mold body with respect to the baffle member and define a plurality of conduits which allow the passage of coolant from the conduit defined by the baffle member and the mold body to the surface of an emerging ingot during casting; and

d. means to urge said mold flange into a water-tight sealing engagement with said first extending leg of said coolant jacket.

12. The mold assembly of claim 11 wherein said spacing member is a projecting ridge formed integral with the baffle member and is provided with a plurality of coolant carrying passageways adapted to direct coolant onto the surface of an emerging ingot during cast- 13. The mold assembly of claim 11 provided with conduit means in fluid communication with the coolant chamber defined by the mold flange the first and sec ond extending legs of the coolant jacket and the baffle member to direct coolant from said chamber onto the outer surface of the mold body in the area of the junction of the mold flange and mold body so as to maintain a high heat transfer rate in said area.

Claims

1. A DC mold assembly for casting light metals which allows for the rapid change of the mold body comprising in combination a. an open-ended tubular mold body provided with a flange extending out radially from the feed end of the mold body and provided with at least one recess in the outer surface of the mold body; b. a coolant jacket comprising a first extending leg generally concentric with the mold body, a second extending leg generally perpendicular to the first extending leg and a baffle member disposed between the first extending leg and the mold body, the mating surfaces of the first extending leg and the mold flange being adapted to receive a coolant-sealing gasket; c. at least one spacing member extending inwardly from the baffle member and seated in the recess provided in the outer surface of the mold body to thereby positively position radially and axially the mold body with respect to the baffle member and define a plurality of conduits which allow the passage of coolant from the conduit defined by the baffle member and the mold body to the surface of an emerging ingot during casting; d. a resilient, rubber-like gasket provided between the mating surfaces of the first extending leg of the coolant jacket and the mold flange; and e. means to urge the mold flange into a water-tight engagement with the first extending leg of the coolant jacket.

9. The mold assembly of claim 1 wherein said baffle member is a separate member and is seated and supported in a recess provided in said horizontally disposed portion of said coolant jacket.

10. The mold assembly of claim 1 provided with second conduit means in fluid communication with the coolant chamber defined by the mold flange, the first and second extending legs of the coolant jacket and the baffle member to direct coolant from said chamber onto the outer surface of the mold body in the area of the junction of the mold flange and mold body so as to maintain a high heat transfer rate in said area.

11. A DC mold assembly for casting light metals comprising in combination a. an open-ended tubular mold body provided with a flange extending out radially from the feed end of said mold body and provided with at least one recess in the outer surface thereof; b. a coolant jacket comprising a first extending leg generally concentric with the mold body, a second extending leg generally perpendicular to the first extending leg and a baffle member disposed between the first extending leg and the mold body, the mating surfaces of the first extending leg and the mold flange adapted to receive a coolant sealing gasket; c. at least one spacing member extending inwardly from said baffle member and seated in the recess provided in the outer surface of the mold body to thereby positively position radially and axially the mold body with respect to the baffle member and define a plurality of conduits which allow the passage of coolant from the conduit defined by the baffle member and the mold body to the surface of an emerging ingot during casting; and d. means to urge said mold flange into a water-tight sealing engagement with said first extending leg of said coolant jacket.

12. The mold assembly of claim 11 wherein said spacing member is a projecting ridge formed integral with the baffle member and is provided with a plurality of coolant carrying passageways adapted to direct coolant onto the surface of an emerging ingot during casting.

13. The mold assembly of claim 11 provided with conduit means in fluid communication with the coolant chamber defined by the mold flange, the first and second extending legs of the coolant jacket and the baffle member to direct coolant from said chamber onto the outer surface of the mold body in the area of the junction of the mold flange and mold body so as to maintain a high heat transfer rate in said area.