US3142873A - Continuous metal casting apparatus - Google Patents

Description

A g- 1964 R. w. HAZELETT ETAL 3,142,873

CONTINUOUS METAL CASTING APPARATUS 5 Sheets-Sheet 1 Original Filed March 17, 1958 INVENTORS P051 27 WILL/AM HAIL-2577' mam/w HAZEZgTT @421: lm/us 4 ATTORNEYS g- 1964 R. w. HAZELETT ETAL 3,142,873

CONTINUOUS METAL CASTING APPARATUS Original Filed March 17, 1958 5 Sheets-Sheet 2 INVENTORS ROBERT WILL/AM HAZELETT R/CHAED f/HZELETT BY aura; Hm: Hm

ATTORNEYS g- 1964 R. w. HAZELETT ETAL 3,142,873

CONTINUOUS METAL CASTING APPARATUS Original Filed March 17, 1958 5 Sheets-Sheet 3 h. @QM NY- U u x 4 n 0 INVENTORS EOBEAT w/u/AM HAZELEI'T ATTORNEYS Aug. 4, 1 ,R. w. HAZELETT ETAL 3,142,373

CONTINUOUS METAL CASTING APPARATUS Original Filed March 17. 1958 5 Sheets-Sheet 4 ZZZ N INVENTORS FOBEfT W/LL/HM HAZELET RICH/9RD HAZEETT By 6422 lb-vurfiw ATTOR N EYS 4, 1964 R. w. HAZELETT ETAL 3,142,873

- CONTINUOUS METAL CASTING APPARATUS Original Filed March 17. 1958 5 Sheets-Sheet 5 INVENTOR ATTORNEYS United States Patent 3,142,873 CONTINUGUS METAL CASTING APPARATUS Robert William Hazelett, Burlington, Vt., and Richard Hazeiett, Rocky River, Ohio, assignors to Hazeiett Strip- Casting Corporation, Fairfield, Conn.

Original application Mar. 17, 1958, Ser. No. 722,005, now Patent No. 3,036,348, dated May 29, 1962. Divided and this application May 22, 1961, Ser. No. 125,301

3 Claims. (Cl. 2257.4)

This invention relates to machines and processes for casting metal strips directly from molten metal and more particularly for continuously casting metal strips between spaced parallel portions of a pair of flexible metal belts which are moved along with opposite surfaces of the strip being cast.

The invention is described as embodied in the structure of a continuous strip-casting machine in which the molten metal is fed into a casting region between opposed parallel portions of a pair of moving flexible metal belts. The moving belts confine the molten metal between them and carry the molten metal along as it solidifies into a strip between them. Spaced rollers having narrow ridges support and drive the belts while holding them accurately positioned and aligned as they move along so as to produce metal strip of high quality and having good surface qualities. The vast quantities of heat liberated by the molten metal as it solidifies are withdrawn through the portions of the two belts which are adjacent to the metal being cast. This large amount of heat is withdrawn by cooling the reverse surfaces of the belts by means of rapidly moving substantially continuous films of liquid coolant travelling along against these surfaces.

It is an object of the present invention to provide apparatus for continuously casting metal strip of high quality directly from molten metal.

It is an object of the present invention to provide apparatus for continuously casting metal strip directly from molten metal enabling the operator quickly and easily to adjust for casting strip metal of various widths and thicknesses as may be desired.

Advantageously, the carriages which carry the rollers for supporting the casting belts are mechanically isolated from the remainder of the machine so that any stresses or strains in the framework of the machine or in the reservoir tank or base of the machine cannot affect the quality of operation. Such stresses or strains in the framework of the machine may result from racking forces imposed during lifting or moving of the machine or may accumulate over long periods of time as a result of settling of a floor or foundation upon which the machine is standing. Nevertheless, the belt-supporting carriages will remain free of any such imposed forces enabling the belts to run along true courses with respect to each other so as to maintain high quality of product. This isolation of the carriages from the framework is provided by utilizing a three-point suspension for one of the carriages and aligning the other carriage with it. As shown the lower carriage is rigidly supported from the frame at two points but the third point of suspension can freely shift with respect to the frame. Also, the upper carriage is rigidly aligned with the lower carriage at two points while a third point of suspension for the upper carriage can freely shift with respect to the frame.

In this specification and in the accompanying drawings, are described and shown metal casting apparatus embodying this invention and various modifications thereof are indicated, but it is to be understood that these are given for purposes of illustration in order that others skilled in the art may fully understand the invention and the manner of applying the apparatus in practical use so that they may modify and adapt it in various forms, each as may 3,142,873 Patented Aug. 4, 1964 be best suited to the conditions for casting a particular metal or alloy.

The various features, aspects, and advantages of the present invention will be more fully understood from a consideration of the following description of continuous strip casting apparatus incorporating the invention, considered in conjunction with the accompanying drawings, in which:

FIGURE 1 is a perspective view of a continuous stripcasting machine embodying the present invention as seen looking at the input end (molten bath region) of the machine from a position adjacent to the control panel, which is positioned near one corner of the reservoir tank for the cooling liquid. For convenience of illustration the box for the molten metal and the pour distributor which feeds the molten metal down intothe bath region are omitted from this view.

FIGURE 2 is a perspective view of this machine as seen looking at the output end, and showing the control panel;

FIGURE 3 is a longitudinal elevational sectional View taken along a plane perpendicular to the axes of the various rolls and with parts shown partially broken away for clarity of illustration;

FIGURE 4 is a cross sectional view of the machine taken along the line 4-4- of FIGURE 3 looking toward the input end;

FIGURE 5 is a partial perspective view illustrating the three-point suspension system for isolating the carriage support mechanism from any twisting or warping stresses which may be imposed upon the tank or supporting framework when the whole machine is transported.

General Description In this example, as shown in FIGURE 3, the molten metal is supplied from a pouring box 2 made from heat insulating material. The incoming metal is smoothly and uniformly released beneath the surface of the existing molten pool or bath B, which is maintained during operation;

From the bath B the molten metal is carried into the casting region formed between the opposed surfaces of upper and lower flexible casting belts 20 and 22, respectively, and generally indicated at C (please see FIGURE 3). These casting belts are formed of flem'ble and heat resistant sheet metal having a relatively high tensile strength, for example, conventional cold-rolled low-carbon sheet steel having its ends welded together with both surfaces at the weld being ground smooth and flush to form a continuous wide band or belt having a smooth outer or front surface operates very well. The belts are relatively wide and thin, for example, of the order of 46 inches in width and, for example, having a thick ness lying in the range from 0.015 to 0.035 of an inch. This illustrative system operates very well with belts having a thickness of 0.025 of an inch. The two belts are supported and driven by means of upper and lower carriages, generally indicated at U and L, respectively.

These two casting belts are driven at the same linear speed. During operation these belts are held under a high tension, for example, such as 10,000 to 12,000 pounds of tension force are exerted by the main end rolls on each belt for a belt 46 inches wide, as shown. The belts are supported, that is, backed up so that their opposed front surfaces are held planar and uniformly spaced over the length of the casting region C. The molten metal is solidified between the casting belts by withdrawing heat through them by means of liquid coolant 24 (FIGURES 1 and 2) supplied into numerous nozzle and header assemblies 23 and 25 from a reservoir tank 26 extending beneath the machine.

As shown in FIGURE 2, the liquid coolant 24 is drawn from the reservoir 26 through a large conduit 27 feeding to a large capacity centrifugal pump (not shown), for example, such as a double-suction, single stage centrifugal pump having a capacity of 3,000 gallons per minute and driven by a 75 horsepower motor. This liquid is returned through a flexible coupling conduit 29 to a coolant supply main 31 (please see FIGURES 1 and 4) which extends along the rear of the machine and feeds coolant into the various nozzle and header assemblies 23 and 25 and also to other headers. Because of the large quantities of coolant being pumped, it is desirable to avoid any sharp bends in the conduit or supply main. The pump is positioned as close to the side of the tank 26 as convenient and then a large radius sweeping curve feeds up into the flexible coupling 29.

As will be explained in detail, the upper carriage U can be raised further away from the lower carriage or lowered down closer to the lower carriage so as to cast strips of various thickness. The width of the strip being cast is determined by the spacing between a pair of moving side dams 2S and 30 which run between the respective edges of the casting belts in the casting region (please see also FIGURE 4) and also is determined by the spacing between a pair of stationary side dams 32 and 34 (please see FIGURE 1) in the bath region which are associated with the respective moving side dams 28 and 30. This spacing between these sets of dams is readily adjusted so as to change the width of cast strip.

One of the advantages of the present apparatus is the ease with which adjustment is made to produce strips of dilferent widths. The upper ends of the stationary dams 32 and 34 are adjustably held by a pair of clamps 60 and 62, respectively. Each clamp includese a pair of grooved slides 64, as indicated in FIGURE 1, which run along lateral ways 66 formed by the opposite edges of the upper flange of an Lbeam 65. These ways 66 are machined so as to be square edged and truly parallel. To lock these clamps in position, the operator tightens the clamping screws 67 which are anchored in the edges of a vertical bracket having a pair of slots in its upper end so as to permit vertical adjustment of the free end of the stationary dam which is locked to these slots by clamping bolts 70 (as shown also in FIGURE 1).

As mentioned in the introductory portion of the specification, the molten metal solidifies between the upper and lower belts 20 and 22. During this solidification tremendous quantities of heat are liberated per unit weight of strip being cast because, in addition to cooling the molten metal down to its freezing point, its heat of fusion must be removed as it solidifies, and then cooled further before discharge from between the belts.

In order to give the reader an impression of relative size it is noted that in this example the total distance in FIGURE 3 from the point beneath the nip roll 44 at which the upper belt 22 first straightens out after passing under this roll over to the point beneath the upper downstream main roll 78 at which the upper belt first begins to curve up around this roll is 4 feet and 1 inch. The total distance from the point at which the lower belt 20 first straightens out after passing around the lower upstream roll 80 over to the point at which the lower belt begins curving down around the lower downstream roll 82 is a total distance of 6 feet inches.

In order to provide tremendous cooling capacity to these planar portions of the belts, substantially continuous high speed films of coolant are created and maintained flowing along at high speed against their respective reverse surfaces.

T hree-Poinf S tress-I solution Cantilever Support System for Belt Carriages In order to isolate the upper and lower belt carriages U and L from any stresses imposed on the framework of the apparatus such as may occur during transportation, installation, or over periods of time, there is an advantageous three-point cantilever support system.

As seen in FIGURES l, 2, 3, and 4 the main framework of the apparatus includes a pair of columns 188 and 189 near the input and discharge ends, respectively. A top beam 1% spans across between the upper ends of these columns, and it has a downward inclination corre sponding to that of the casting region C. As seen in FIGURE 4 this top beam 1% is formed by a pair of spaced back-to-back channel members 191 and 192, which are rigidly fastened together by pairs of plates 1% and 1% (FIGURE 1) and braced by pairs of diagonals I and 1% (FIGURE 3). A hoist plate 197 (FIGURE 1) is secured to the column 188 between the diagonal braces 195, and other hoist connections (not shown) are provided near the corners of the machine inside of the tank 26 near the bottom. As seen best in FIGURES 3 and 4 a sill I-beam 198 spans between the columns 188 and 189 and is parallel with the top beam. This sill beam is braced from underneath by diagonal members 199 and 2tl0a which extend down to the bottom of the tank adjacent to the foot of each of these columns.

The lower belt carriage L which supports and operates the lower belt 22 includes a pair of parallel long narrow rectangular frames 200 extending between opposite ends of the main lower rolls S0 and 82. As seen most clearly in FIGURES l and 2 these main lower rolls have short projecting shafts 261 and 202 which are journaled in bearings carried by pillow blocks 203 and 204 at each end of each frame 200. Each frame 200 includes a longitudinal upper frame element 206 carrying the back-up rollers and cooling header assemblies 23 and 25 and includes a longitudinal lower frame element 208. In order to prevent racking of the lower carriage, an X-frame formed by a pair of angle irons 209 and 210 (FIGURES 3 and 4) extends across between the longitudinal elements 208, with a wide thick plate brace forming the bottom of a gutter 129 and providing additional strength.

This lower carriage is suspended solely by means of a pair of spaced, parallel inverted T-shaped cantilever arms 212 and 214 (FIGURE 3) which extend across the width of the lower carriage passing between the upper and lower longitudinal elements 206 and 203. It will be noted in FIGURE 4 that the ends of the X-frame 209 and 210 are secured to the lower flanges of these cantilever arms at 215 and 216.

These cantilever arms 212 and 214 are each supported at a point where they res-t on top of the sill beam 198, as seen in FIGURES 4- and 5, thus providing two points of support for the lower carriage. A third free-floating point of support for the back ends of these two cantilever arms 212 and 214 is provided by a pivoted link 217. The upper end of this link 217 is loosely held by a pivot pin 218 passing through a pair of channels 219 and 220 which interconnect the rear ends of the cantilever arms 212 and 214. A pivot pin 221 secures the lower end of this link to a pair of blocks 222 which are rigidly secured to a second sill I-beam 223 which runs along the rear edge of the tank 26. This beam 223 is supported at one end by a column 224 (FIGURE 1) and at the other end by a column 225 (FIGURE 2).

In order to prevent any racking movement of the cantilever arms 212 and 214 with respect to each other they are rigidly tied together by a large diameter torqueresisting brace 226. This brace 226 is welded to triangular end plates 227 secured to the outer flanges of the cantilever arms and to saddle plates 228 welded to the inner flange of each arm. Thus, it will be appreciated that the lower belt carriage L is rigidly stiffened internally by an X-frame and a large torque brace and is externally supported at two points by the sill beam 198 and at a third free-floating point by the link 217 which is loosely pivoted at both ends. Thus, the cantilever arms 212 and 214 are advantageously isolated from any motion of the sill beam 223 relative to beam 193 as caused by external forces.

By virtue of the cantilever support, the front side of the lower carriage L is entirely accessible, and the belt 22 and dams 28 and 30 can be readily slid on and off. The large tension force for the lower belt is applied by a rubber-coated tensioning roller 230 which is operated by a bell-crank 232 and a pressure-operated cylinder and piston 234 secured to the carriage frame 200 by a bracket 236 (FIGURE 2) and pivot pin 237; a similar arrangement is used for tensioning the upper belt.

The upper belt carriage U is generally similar to the lower one except that the two rectangular frames 240 are shorter and higher and have input end members 241 extending up to carry an upper main roll 242 which is located generally above the nip roll 44. The upper downstream roll 78 is carried by a pair of pillow blocks 243, and a rubber-coated belt-tensioning roller 230 is used. Each frame 240 includes a lower longitudinal element 244 carrying the back-up rollers 86 and the nozzle and header assemblies 23 and 25, and includes an upper parallel longitudinal element 246.

As seen in FIGURE 3, the two end members 241 are held rigidly together by a horizontal and a vertical brace plate 247 and 248. Another wide horizontal brace plate is shown at 249 extending between the longitudinal elements 246 and a second vertical brace plate at 256. These brace plates are all lightened by central circular cut-outs, as seen in section.

As shown in FIGURES 4 and 5 the upper carriage advantageously is supported so as to float entirely free of the framework of the machine by means of a pivoted link 252 whose lower end is loosely fastened by a pivot pin 253 to a pair of blocks 254 secured to the channels 219 and 220 above the link 217. Also, as seen in FIGURES 1, 2, 3, and 4, a large pressure-operated cylinder and piston 255 are supported on the channels 191 and 192 of the top beam 190 by means of a pair of trunnion pivots 256 and 257. A piston rod 258 extends down from the cylinder 255 and is connected by a pivot 259 to a pair of parallel links 260 so as to support the upper carriage U. In this way the upper carriage is quite isolated from stresses in the framework.

In order to hold the two carriages in proper alignment with each other, there are a pair of upstanding guide rods 262 and 264 rigidly secured to the frames 200 of the lower carriage by pairs of brackets 265 and 266. Corresponding pairs of brackets 267 and 268 are secured to the frames 240 of the upper carriage and slidingly engage these guide rods. These rods are canted at an angle to the vertical so that they are perpendicular to the plane of the casting region C. The upper ends of these rods are loosely held in a bracket 269 which is connected to the top beam 190 so as to isolate the guide rods from the framework. Thus, the guide rods maintain alignment of the carriages as the upper carriage is raised or lowered and in spite of external stresses imposed on the apparatus.

T o raise and lower the upper carriage, a lever 270 of the third-class is provided, projecting into the upper carriage. The slotted front end of this lever straddles a bracket 271 and is pivoted thereto by a pin 273. This bracket extends down from between a pair of heavy transverse members 272 which are secured to both frames 240 and thus supports the upper carriage. A fulcrum for this lever 270 is established at the remote end by a pivot pin 274 passing through the upper end of the floating link 252. The supporting force is applied to the center portion of this lever 270 by a roller pin 276 passing through the lower ends of the two parallel pivoted links 260 and freely engaging the lower edge of the lever, and thus providing further isolation between the lever 270 and the top beam 190.

This utilization of a third-class lever with a remote fulcrum is extremely advantageous because it enables a reduction in the required height for the upper carriage. In fact, the rear end of the lever between the pivot 276 and the fulcrum pin 274 is purposely arranged to be longer than the portion between pivots 276 and 273. In operation this lever swings through a relatively small angle while providing a relatively great up and down travel of approximately 10 inches for the upper carriage. It will be noted in FIGURE 4 that the longitudinal frame elements 244 and 246 are not required to be spaced very far apart and yet there is suflicient clearance for operation of the lever 27 0.

To obtain the desired supporting force, the air cylinder 255 has a bore diameter of 16 inches. In operation the spacing between the upper and lower carriages is provided by a series of precise spacing stops 278 which fit into sockets along the upper edges of the frame elements 206 and engage against the underside of the frames of the upper carriage. When it is desired to cast a thicker or thinner strip the upper carriage is raised and the moving edge dams and spacers 278 are correspondingly changed.

The cantilever support of upper carriage U provides ready accessibility to the casting region merely by raising the upper carriage and enables the upper belt to be quickly and easily slid off and replaced if desired.

As shown most clearly in FIGURES 2 and 3, the belts 20 and 21 are driven at an adjustable speed by means of a 2-H.P. electric motor 322 coupled through a variable speed-reducer 324, to a sprocket chain 326. This chain passes around a fixed sprocket 328 and engages suitable sprockets fixed on the shafts of the rolls 78 and 82. An automatic spring-loaded chain tensioner and sprocket is shown at 330. With this drive arrangement the upper belt can always be driven regardless of the elevation of the upper carriage.

As used herein the following word is intended to have the following meaning: Strip is intended to include an elongated plate or slab having substantial width and thickness as well as thin, narrow slats.

From the foregoing it will be understood that the continuous strip casting apparatus of the present invention described above are well suited to provide the advantages set forth, and since many posisble embodiments may be made of the various features of this invention and as the apparatus herein described may be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and that in certain instances, some of the features of the invention may be used without a corresponding use of other features, all without departing from the scope of the invention.

This application is a division of our copending application Serial Number 722,005, filed March 17, 1958, now matured into Patent Number 3,036,348, issued May 29, 1962.

We claim:

1. Apparatus for casting metal strip directly from molten metal comprising a machine framework, first and second belt carriages each including a frame with spaced pulleys and an endless flexible band extending thereover, cantilever means supporting said first belt carriage at three points of support for mechanically isolating said first belt carriage from stresses imposed upon the machine framework comprising first and second cantilever arms each having one end secured to the frame of the first carriage, said arms being rigidly supported by said framework at first and second positions, respectively, for providing two points of support for said first belt carriage and a link pivotally connected to said arms and to said machine framework for providing a third common point of support for said arms, said link being movable in relation to said arms and in relation to said machine framework, guide means rigidly secured to the frame of the first carriage, the frame of the second carriage slidingly engaging said guide means for sliding motion therealong toward and away from the first carriage, a movable supporting element connected to the frame of the second carriage, and motive mechanism connected to said movable support element for moving the second carriage along said guide means.

2. Continuous metal casting apparatus for casting molten metal between a pair of moving endless flexible bands comprising a machine frame, first and second carriages each including spaced rolls and an endless flexible band traveling around said carriage as guided by said rolls, cantilever means supporting said first carriage at three points of support for mechanically isolating said first carriage from stresses imposed upon the machine frame comprising first and second spaced, parallel cantilever arms each having a first end secured to said first carriage, first support means included in said machine frame for supporting an intermediate portion of said first and second cantilever arms for providing two points of support for said first carriage, said cantilever arms each having their second ends interconnected and spaced from the machine frame, second support means included in said machine frame, a support element movably connected to said second support means and movably connected to the second ends of said arms, said support element being movable in relation to said machine frame and in relation to said arms for providing a third movable point of support for said first carriage, thereby to isolate said first carriage from stresses imposed upon the machine frame, and third support means including carriage moving means for supporting said second carriage and for moving said second carriage toward and away from said first carriage in relation to said first carriage.

3. Continuous metal casting apparatus as claimed in claim 2 and including a torque-resisting tubular brace rigidly interconnecting said first and second cantilever arms.

References Cited in the file of this patent UNITED STATES PATENTS 2,904,860 Hazelett Sept. 22, 1959

Claims (1)

1. APPARATUS FOR CASTING METAL STRIP DIRECTLY FROM MOLTEN METAL COMPRISING A MACHINE FRAMEWORK, FIRST AND SECOND BELT CARRIAGES EACH INCLUDING A FRAME WITH SPACED PULLEYS AND AN ENDLESS FLEXIBLE BAND EXTENDING THEREOVER, CANTILEVER MEANS SUPPORTING SAID FIRST BELT CARRIAGE AT THREE POINTS OF SUPPORT FOR MECHANICALLY ISOLATING SAID FIRST BELT CARRIAGE FROM STRESSES IMPOSED UPON THE MACHINE FRAMEWORK COMPRISING FIRST AND SECOND CANTILEVER ARMS EACH HAVING ONE END SECURED TO THE FRAME OF THE FIRST CARRIAGE, SAID ARMS BEING RIGIDLY SUPPORTED BY SAID FRAMEWORK AT FIRST AND SECOND POSITIONS, RESPECTIVELY, FOR PROVIDING TWO POINTS OF SUPPORT FOR SAID FIRST BELT CARRIAGE AND A LINK PIVOTALLY CONNECTED TO SAID ARMS AND TO SAID MACHINE FRAMEWORK FOR PROVIDING A THIRD COMMON POINT OF SUPPORT FOR SAID ARMS, SAID LINK BEING MOVABLE IN RELATION TO SAID ARMS AND IN RELATION TO SAID MACHINE FRAMEWORK, GUIDE MEANS

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