US2383310A - Continuous casting apparatus and process - Google Patents

Description

x 1945- c. w. HAZELETT 2,383,310

CONTINUOUS CASTING APPARATUS AND PROCESS Fil ed Mardh 16, 1939 4 Sheets-Sheet l INVENTOR CLfl/QE/VCE VKHHZELETT BY (1mm ATTORNEY c. w. HAZELETT CONTINUOUS CASTING APPARATUS AND PROCESS 4 Sheets-Sheet 2 Filed March 16, 1939 INVEN'TCVJR CLfl/PENCEWHHZELETT' ATTORNEY Aug. 21, 1945. c. w. HAZELETT CONTINUOUS CASTING APPARATUS AND PROCESS '4 Sheets-Sheet 5 Filed March 16, 1959 INVENTOR CLARENCE/K697254577 agmr ATTORNEY CONTINUOUS CASTING APPARATUS AND PROCESS Filed March 16, 1959 4 Sheets-Sheet 4 3 INVENTOR CZ/ffiE YCE WH/YZELETT TI'ORINEY Patented Aug. 21, 1945 CONTINUOUS CASTING APPARATUS AND PROCESS Clarence W. Hazelett, Greenwich, Conn.

Application March 16, 1939, Serial No. 262,223 6 Claims. (c1. 22-572) The present invention relates to the artof metal casting and working and, more particularly, to a novel process of producing metallic shapes or Strips directlyjrom molten metal and to an apparatus therefor and to the product thereof.

It is an object of the present invention to provide a process of producing metallic shapes or strips directly from molten metal which eliminates the disadvantages of conventional processes.

It is another object of the present invention to provide a novel and improved process of producing metallic bodies of elongated character directly from molten metalwhich may be applied to the production of sheets, strips, and the like, constituted of high melting point metals including steel.

It is a further object of the present invention to provide a high speed process for producing metallic shapes directly from molten metal which involves pouring molten metal on to a cooling member in the form'of a ring or roll rotated at high speeds.

Still another object of the invention is to provide an apparatus for carrying the process of the invention into practice.

The invention alsocontemplates the provision of an apparatus for the continuous production of metallic bodies of constant cross section directly -'from molten metal including a main cooling member preferably of a ring or shell-like character onto the outer or inner surface of which the molten metal is poured and is carried upwards by the rotation of said member.

Other and further objects and advantages of the invention will become apparent from the fol lowing description taken in conjunction with the accompanying drawings, in which- Fig. .1 illustrates an end view having parts in section of a mill embodying the principles of the present invention; I

Fig. 2 depicts a side elevational view having parts in section of the mill illustrated in Fig. 1;

Fig. 3 shows a modified embodiment of the inacter, .of another modified embodiment of the invention into a mill;

Fig. 6 depicts a top elevational view of the metal feeding distributor shown in Fig. 5;-

Fig. 7 shows a fragmentary vertical'sectional view of a modification of the mill illustrated in Fig. 3 which is especially adapted to the production of metallic bodies having accentuated cross sections; I

Fig. 8 is a photomicrograph of a cross section of the product of the invention; and

Fig. 9 is a diagrammatic view of a further modified embodiment of the invention.

Broadly stated, according to the principles of my invention, I provide a main cooling member in the form of a roll or preferably in the form of a hollow shell or ring, and provide drivin means for causing displacement of the outer surface of said cooling member along a circular path. Onto the surface of said cooling member I feedv a molten metal which will solidify and will be moved upwards up to a point where it is again removedand separated from the surface of the cooling member. I have found that a mill of the described type can be operated at ring or roll and the vertical is not more than 40.

degrees. To make this angle. the largest possible, compressed gas preferably of a reducing nature may be blown against the stream of molten metal in a substantially tangential direction in order to prevent running of the metal backwards. Like wise; a back dam of suitable character may be employed preferably in combination with the stream of compressed gas.

The main cooling member cooperates with one or more auxiliary cooling members generally provided in the form of a roll or shell; The auxiliary cooling member or members exert a cooling effect and in most cases some rolling pressure upon the surface of the solidified metal. it is'generally'preferred to employ rings for both the main and the auxiliary cooling members. The advantage of the ring type structure is that cooling members of very great circumference may be employed without making the weight or the cost of the structure excessive. Backing rolls of suitable dimensions are provided within the rings in proximity to the point of tangency thereof in order to take up' the pressure at these points.

Another important advantage of the ring-like v the product. v

cooling members is that they may be constituted of relatively expensive, high strength and high melting metals which will not scale at the temperatures necessary for degassing, whereas the inner or backing rolls may be made of cheap steel. The relatively thin and shell-like construction of the main and auxiliary members also makes possible eflicient inner or both inner and outer cooling thereof which would be unobtainable with solid rolls. Ofvital importance is the circumstancegthat a ring maybe readily preheated and degassed, while this would be impracticable with a roll.

According to a. modification of my process inner surface and by laterally arranged flanges of the ring. The ring is supported by a plurality of back up rolls at least one of which cooperates with a surfacing roll arranged within the inner space of the ring and exerts a pressure upon the surface' of the solidified metal. Rotation of the ring is obtained by rotating'the surfacing roll and the backing roll cooperating therewith. I found it advantageous to provide a reducing gas atmosphere above the bath. Bone black or some other facing material may be applied to the inner surface of the circular dams or flanges of the ring to decrease the amount of chilling by these members and to facilitate the removal of In another modificationof the process of the are provided witli'a pin or 'similarpr otniding member I2 l engaging lower bearing housing I4 slidably mounted in ways I5 so .that by actua tion of cylinders l0, bearing housing l4 and .thereby lower roll I may be raised to any desired ring 9 has to -be replaced; The right hand thrust bearing I6 presses against the right hand housing, whereas the left hand one is held against the endof the top ring by'spring means I1 to allow 'for expansion of the ring. A.pointer I8 invention, one or a plurality of strips of metal produced by the present process or by a conventional process are fed over a ring. or roll, after having been passed through heating furnaces. Molten metal is subsequently poured much in the same manner as in the other embodiments of .theinvention, except that one or both of they cooling surfaces will be formed by said strips. The pressure present in the surface of contact and the high temperature of the molten metal causes welding of the molten metal to the solid of the invention is illustrated. The mill essentially comprises a lowerroll I mounted in roller bearings 2ina housing 3. Roll I is provided I with a groove 4 in which travels a ring 5 constituting the main cooling member of the mill.

Ring 5- is driven in the following manner: A suitable motor (not shown) is attached to an upper roll shaft 6 and drives the same in roller bearings I. Shaft't supports upper roll 8 carrying a surfacing ring 9. When the mill is running pressing against surfacing ring 9, which in turn means of air or hydraulic cylinders l0, As it will be best observed in Fig. 2, fluid pressure cylinders III are pivotally mounted on a base or support Ill-l and are provided with anupwardly ex- Connecting rod tending connecting rod I02.

'60 idle, lower roll I ispressed against ring 5, ring 5 the lower roll and is equipped with a zero adjustment screw I9. Roll I. is chamfered at 2! to cause any water accumulatingat this point to run off easily as otherwise explosions could be caused by molten metal reaching thispoint. Surfacing ring 8 is internally cooled by means of water sprayed against the inner surface thereof through the apertures 22 ofpipe 23. Suitable" channels 24 are provided through which the water may runoff. It is important that ring 9 shall be wider than the width of lower roll I so that the cooling water is discharged beyond said r011 to prevent explosions when an excess of metal is poured on ring 5.

Ring 5.may be of any suitable diameter and in practical and industrial operation may be from about 10 to about 50 feet in diameter. Thisring may be omitted in the production of shapes constituted of low melting point metals, such as lead or tin, but large diameter rings are particularly suitable for the production of brass, copper, and steel strips directly from molten metal. As

large diameter rings of the described character and traveling at the very high speeds possible in this mill may whip, for the prevention of this, one or more rollers 25 bearing against the outer surface of the ring may be provided.

The metal feeding means (Fig.2) include a conventional ladle 26, such as is used for 'pourbaflle 61 of refractory material prevents the over-- flow of slag into the mill. Due to the extremely great operating speed of this mill compared to: any one heretofore built, it is possible and is preferred to pour the metal over-a weir or straight edge 3|. This was'impossible in prior direct casting and rolling processes as uniform pouring over a weir cannot be obtained unless much larger quantities of metal are poured in a given time than heretofore. When small quantities-of metal are poured, due to surface tension I phenomena, the -metal runs irregularly and in is pressed against thedriven roll 8. It is to be Ill-2 is jointedly connected to one of the ends of a lever II having its other end fulcrumed in individual streams, giving entirely unsatisfactory results. Afterpassing over weir 3|. the'metal pours over shelf 32 against baffle 33 which carries the metal close to the surface of ring 5. At the operating speeds contemplated by the present invention, the metal will not run backwards and downwards, provided the angle between the radius to the point where the stream of molten metal strikes the ring or roll and the vertical does not exceed 40 degrees. To make this angle as large as possible, a pipe 34 is provided through which compressed gas, preferably of a reducing gentially and in the direction of the rotation of the main cooling member or ring 5. This is accomplished by. providing a large number of, holes or nozzles in pipe 34 through which the gas under pressure is blown in the direction of the molten metal and positively prevents its flowing backwards by cooling it and by exerting pressure upon the same. Additional advantages may be obtained bysupplying pipe 34 with a combustible gas which may be used for preheating the surface of ring 5. At a small distance from the point of contact of the molten metal with ring and in the direction of movement of the ring, a cooling roll 35 may be provided. This is a thin-walled, internally cooled roll, which merely cools the upper surface of the molten metal, but does not exert any actual pressurethereon, nor does it solidify the molten metal except on the immediate surface. Cooling roll 35 may be driven by a sprocket wheel 36 through a chain 31. The provision of cooling roll 35 permits a still further increase in the speed of production as well as an increase in the thickness of the product. Surfacing ring 5 is water cooled by means of a pipe 38 having a large number of discharge openings or nozzles 38-l therein and preferably supplied with water at .very high pressures. Similar water cooling means (not shown) may be provided for externally cooling the ring. Lower back-up roll I may be additionally cooled by means of a water pipe 39, and in some cases the strip produced may be cooled by spraying high pressure water thereon by means of a pipe 40. The interior of ring 5 is scraped clean by means of a scraper 4i and an- -'other scraper is provided for removing the produced strip from ring5. .A similar scraper (not shown) serving the same purpose of maintaining the surface of top ring or roll 9 clean may be provided. v

Fig. 2 also illustrates the method and means of controlling the gauge of the finished product by varying the speed and the pressure. Increase in the thickness of the product will cause downward displacement of ring 5 and of roll ,I rotatably mounted in bearing housing l4, which is slidably mounted in ways I5 and is yieldingly supported by means of levers ll associated with fluid pressure cylinders I0. Reference character 43 denotes a carbon pile rheostat inserted in series with shunt field winding 44 of mill driving motor 45 having a series field winding 45--l and being connected to a source of current 452. Rheostat 43 is so connected with lever II that an increase in the thickness of the product, which results in the lower bearing l4 dropping downward, decreases the pressure on the rheostat and increases its resistance. 'I'his-in turn will decrease the current in the shunt field winding of the motor causing speeding up of motor 45, and bringing the hot metal in contact with surfacing ring 9 in a shorter period of time, thereby' causing the sheet to be made thinner. The air or liquid pressure supplied to cylinder Ill may also be varied, and such pressure is indicated by a pressure gauge 46. An increase in this pressure will decrease the thickness of the product and will also increase the amount of work'done on itand the degree of refinement imparted to the structure thereof. It will be understood'that provision is made for varying the pressure on From the preceding description, the operation of the mill embodying the invention will be readily understood by those skilled in the art. Shaft G of top backing roll 8 is driven by motor 45 at a predetermined high speed. Stopper 21 in ladle 2B is lifted permitting metal to fiow into distributor or pouring box 28 wherefrom it may be poured at a manually or automatically controlled rate over weir 3| and along shelf 32 against baflle 33 which carries the metal close to the surface of ring 5. Fluid pressure is applied to cylinders l0 thus causing pressure on the metal solidified on ring 5 by the adjustable and yielding pressure means. Of course, the velocity of the main and auxiliary cooling membersor rings 5 and 9, the amount of metal fed against the main cooling "member in the unit of time, the period of compression of the solidified metal on the cooling members have to be critically controlled in accordance with the principles of my invention, as it will be explained more fully hereinafter. The finished strip is removed by means of scraper 42 and may be subjected to re-rolling on its initial heat or may be cooled and rolled up or out to individual lengths. To prevent damage to the rolls due to the cold drops of metal, it is highly desirable to turnon the air pressure after the molten metal has started through the mill and to release it before the Dour is finished. It has been also found that compressed air moves rapidly enough through orifices and pipes to accomplish the desired result.

Figs. 3 and 4 illustrate a modified apparatus for "carrying the process of the invention into practice, which is especially adaptable to the producover a weir 49-l into bath 50 which is supported by ring 41 and the end flanges or circular dams skimming baffles 52 extend into bath 5!! to collect. the slag on the upper surface thereof. High pressure water issprayed onto the outer surface of ring 41 directly beneath the bath and elsewhere, if desired, through pipes- 53. Ring 41 is supported by a back up roll 54 and a surfacing roll 55 which in this case is shown as a thin-walled,

internally cooled, cylindrical shell. Of course,

surfacing roll 58 may be of the same construction as ring 9 and backing roll 8 shown in Fig. l. A reducing gas atmosphere is provided over the bath through a pipe 51. Power is supplied through surfacing roll 56 which is connected to a motor, (not shown).

.material to the inner surface of circular dams 5| to decrease the amount of chilling by these members and to facilitate the removal of the product. The distributor box 49 may be tilted on pivot 59 to control the pouring more accurately, much in the same manner as this is shown in Fig. 2. Fig. 4 depicts a sectional view of ring 41 and of circu'lar dams 5| which may either be integral with ring 41 or may be adjustable in order to vary the width of the product. As it will be readily understood from Figs-3 and 4, when ring 41 is rotated by applying power to surfacing ring 55, metal will solidify in the form of a layer on the inner surface of ring 41 as .it emerges from oath 50,'due to the Molten metal obtained from any suitable A container 58 is provided to apply bone black or some other suitable facing prevent the molten metal from running backwards and downwards thereon. This construction can be used"oniy.w,here the speed of the mill exceeds a definite and predetermined amount. Since any material in contact with ring orroll -6I will be cooled by it, molten metal will freeze to. it at the coldest point, to wit: at the line of contact with the ring or roll; I have discovered that this can be avoided by so constructing the mill and by providing such spaced relations between its parts that speeds in excess of 120 feet per minute are obtained, and by so arranging the pour that the maximum possible amount, of incoming metal flows by this junction point between the stationary dam 62 and the moving roll or ring 6|. By either of these means freezing of the metal at these critical points, which may make the mill entirely inoperative, may be avoided. For high melting point metals, I prefer to use a refractory lining to the box 60 and a shoe made of copper or nickel sheet between the refractory and the roll. This sheet wears much longer than any refractory material and does not spall off, causing defects in th product from the inclusions. Moreover, by the production of strips at such high speeds, the strip may be re-rolled on its initial heat, as this is indicated by rolls 63 in Fig. 5. Of course, this was altogether impossible with the speeds heretofore obtained in direct fabrication. As it appears from Fig. 6, which depicts a top view of box 60, that .part of the dam which extends beyond the line of contact of the dam and'the ring or roll and in the direction of motion thereof, is flared out, as indicated by reference character 64. The effect of this type of construction is to continuously pull away from the vertical surface of this side dam any metal freezing thereto. It is to be noted that the freezing at any point is always cu-- mulative and progresses until a large body has formed, which may then'be released and may get between the main cooling means and the surfacing roll and do great damage to the mill.

Fig. 7 illustrates a modification of the apparatus shown in Fig. 3, in which ring 4'l--I is driven by means other than the cooling and surfacingroll, such as the two supporting rolls 54-1. Sur-, facing roll 56-4, exerts practically no compression on the product but cools'the topsurface of the product after the major portion thereof has been solidified by ring "-4. This apparatus and method are particularly useful in producing thick' slabs with good surfaces on both sides. It is to be noted that no shrinkage can take place, any shrinkage being fed by the molten bath continuously' supplying the 'metal in the center of the slab. The method of cooling and the. distributionof the cooling eifect of the ring is shown by the shaded portion in Fig. 7, denoted by reference character'50l.

The principal advantage of pouring-on their:- side of a ring is that no, back ,dam or barrier is required. This permits slow speed operation for the production'of thicker sections, which cannot be attained with pouring on the exterior'of a ring or roll. As to th removal of the finished the ring, such as is denoted by reference character in Fig. 3, or, if narrow, they may be spiralled outside of the ring on the side thereof.

In the operation of the mill, molten metal is supplied directly from a furnace or a ladle into ,a distributor box extending lengthwise of the mill, such as 28 in Fig. 2, 49 in Fig. 3, or in Fig. 5. The supply of molten metal may be more closely regulated than is possible by tilting a furnace or operating'a stopper by tilting the distributor box manually or automatically. Fromthe distributor box, the molten metal flows in contact'with a relatively large main cooling member which may be a roll for small quantities of metal or for low melting point metal, but should be a ring for the production of large quantities of high melting point strip. The relation of the parts of the mill and their operation should be such as to permit the production of strip in excess of 120 feet per minute when the metal is poured on the outside of the ring. This is necessary for two basic reasons; first, to get uniform and open distribution of high melting point metals, it is necessary to pour at least 700 cubic inches of metal per minute for each foot in width of the mill; and second, to prevent freezing of the metal to the back dam or barrier at the point of contact with said main cooling means.- Furthermore, I have discovered that when metal is poured on the exterior of a cylindrical surface, it is necessary to compress it within a period less than one half of a second after the time it strikes the main cooling means, if the temperature of said cooling means is within the practical operating range of metals suitable for this purpose. If the temperature of the cooling means is above a certain point, the ring itself will be rolled and lengthened by the pressure means of v the main cooling member.

have a greater height above the lower ring then product, the sheets are coiled on s seller within 15 the mill.

I have also found that when the time of contact of the metal with the cooling means exceeds the critical limit referred to in the foregoing, the lower solidified surface has cooled bewhich the upper face of the partly solidified metal is subjected to compression-and to cooling by the secondary cooling member should not ex- 'ceed fifty-per cent of the period of contact with I have found that the quality of the'upper surface depends upon entirely different factors than that of the lower. If the metal fed on to the ring or roll is traveling tangentially in the direction of .its motion, it.

may be carried upwards, causing a: substantial accumulation of molten metal just back of the" I surfacmg roll. In the processof the invention,- the molten metal is carried to the surfacing roll by its friction or cohesion with the metal solidilied on the lower cooling means. I have further found that-in order to produce'a satisfactory top surface with moderate pressures, the metal accumulating. behind the surfacing roll should not three quarters of an inch. A large accumulation causes irregular-cooling and folding, spoiling the product. To avoid this, it is essential to either ass-3,310

operate the mill with the molten metal being fed againstgravity, as shown in Fig. to feed the metal with no appreciable velocity tangential to the direction ofmotion, as shown in Fig. 2; or to pour the metal in such a manner that it is free to flow sidewise, which occurs under the conditions shown in Fig. 5 where the effect of gravity prevents building up of a bath of metal on the roll. I have found that the angle between the radius extending to the point of contact of the molten metal and the vertical center line of the lower cooling ring or roll must not exceed 40 degrees. If this angle exceeds 40 degrees, the metal flows sidewise too much when a back dam is used and backwards too much when no back dam is used.

I have also discovered that further important advantages are obtained by employing shoes with feeding slots for feeding the molten metal onto the circumferential surface of the cooling member in order to produce a plurality of individual streams which merge on the cooling member or ring to-form a stream. This has the advantage of providing very uniform distribution of the flow and at the same time the high velocities of the flow prevent skulling and oxidation of the molten metal. Moreover, heat is conserved by the reduction in radiating surface.

Preferably, cooling means constituted of heatresisting materials are used having substantial chromium nickel or molybdenum contents, as ordinary steels will scale non-uniformly producing non-uniform cooling and cast spots unless continuously brushed, as this is shown at 65, in Fig. 5. Another advantage of using heat-resisting metals is that metals discharge occluded gases when heated until the heating is continued for a substantial length of time. This degassing process has to be carried out at temperatures at which ordinary steels tend to oxidize, whereas the heat-resisting materials contemplated by the present invention such as 18-8 stainless steel, nichrome, and the like, do not oxidize. Likewise, I have found that materials having a lower heat conductivity, such as the above heat resisting materials, do not fire-crack as readily as other materials. It will be readily understood that in my process the under-surface of the prodable by cold rolling. Rings of extremely large diameter may be used, whereas the weight and cost of rolls providing cooling surfaces of the same order would be prohibitive. Strips of accentuated Width can be produced on the mills embodying the present invention in view of the very low horse power required compared even to previous direct rolling mills. High tonnage production is necessary in the production of steel because of the enormous size of the standard ladlesused for open hearth steels and due to the necessity of emptying them'before they freeze. It is also to be observed that the enormous speeds of operation of which the mills of the invention are capable, permit open and weir type pouring, which were never practically accomplished heretofore and which are critically important in pouring high melting point metals such as steel, nickel, Monel metal, and the like, because of the great difficulty in keeping holes or closed pouring devices from freezing. Continuous re-rolling on the initial heat is only possible because of the great speed of this type of mill and particularly with very thin sheets. In the mill embodying the principles 'of the invention it is possible to produce steel and non-ferrous sheets of good quality as low as 0.01" in thickness at speeds of from about 200 to about 2000 feet per minute. High speeds are effected merely by increasing the distance of contact of the molten metal before it is compressed. Many metals must be re-worked before they fall to the "short range. This can be readily accomplished with the process of the invention because of its speed and without any re-heating being necessary.

The structure of the product of the mill and of the process embodying the invention is to a great extent determined by the operating pressures. Thus, when employing high pressures and a surfacing roll of smaller diameter than that of the lower cooling member, the product is subnot is first solidified, and only a molten surface is carried upward to the surfacingroll and that the lower surface has not yet chilled sufflciently at this point to prevent the consolidation of any imperfections in its surface when it is compressed by the surfacing roll. The immediate surface of the metal striking the surfacing roll is molten. It has been found that the practical advantages of employing a ring as a main cooling member-v over a roll are of vital importance. Thus, a ring is much cheaper 'to build and to replace than a roll. The expansion at the two sides of the ring is but little different, which greatly reduces or almost completely eliminates fire cracking so frequently experienced on rolls. In view of the relatively'low weight of the ring as compared to that of a roll of similar dimensions, expensive and heat resisting alloys may be used for the ring and cheap steels for the backing rolls. Rings can be readily cooled both on the outer and on the inner surface thereof and thus facilitate the a production of large quantities of finished products. Since the back-up rolls used with the rings may be operated with water sprays directed thereon, they maintain their low temperatures and shape better than hot rolls, providing in a hot rolling process gauges as accurate as obtainstantially cast on the lower side and shows substantial work or extrusion on the top side. This will be readily observed from Fig.8 depicting a photomicrograph of the cross section of the finished product which is an aluminum strip, magnified 100 times. This product has the ductility due to the working on the top surface thereof and the resistance to corrosion due to the very slightly worked structure on the bottom surface thereof. This can be shownby the fact that the distance between roll marks on the upper surface of the sheet is greater than the circumference of the upper ring or roll and the distance between roll .marks on the lower surface of the sheet is 7 smaller than the circumference of the lower ring or roll, due to the actual shrinkage of the product.. It has been found that the metal in contact with the surfacing roll shows an extrusion on the top surface of the strip of about 10% but i no extrusion whatsoever on the bottom. In other words, the product is a compressed casting on the bottom and substantially a worked metal on the upper surface. A perfect strip is obtained when this extrusion on the top exceeds 10%. On the other hand, when operating under extremely low pressures, as low as pounds per inch width' of the strip being rolled, purely cast products box 10 having a solid barrier or shoe 12 in contact with the cooling member are provided. Reference character M denotes coils of strip metal of any type produced by the process of the present invention or by some conventional process. One or both of thesestrips are fed over ring or roll H first passing through heating furnaces 15 which may be provided with reducing atmospheres, if desired, in order to avoid oxidation, and then through the mill. Molten metal from the distributing box 10 is poured much in the same manner as in the apparatus shown in Fig. 5, except that one or both of the cooling surfaces will be formed by the strip coming from coils 14. A combination of the pressure and of the high temperature of the molten metal will cause welding of the molten metal to the solid strip or strips. The resulting product may be further improved by immediate re-rolling by rolls 13.

for instance having widths from about 2 to about 8 inches, have been produced on the same mill by varying the width of the pouring member said surfaces and under the influence of said pressure means, and means actuated through the separation of said surfaces against said pressure means by the metal passing between said surfaces, for changing the ratio of the speed of movement of said surfaces to the rate of supplying of said metal whereby to control the thick ness of the metal to be formed by said surfaces.

3. In a combination of the class described, a pair of moving surfaces, pressure means yieldingly pressing one of' said surfaces toward the other along a predetermined line, means for depositing molten metal on one of said surfaces to one side of said line, said metal then passing between said surfaces and under the influence of said pressure means, driving means for moving 'said surfaces at variable speeds, and means and the quantity of metal poured. Due to the low power requirements of the mill embodying the invention, the width of the strips produced can be increased considerably above the widths obtainable with ordinary mills. For instance, widths up to about ten feet, or more, can be obtained without difliculty.

Although the present invention has been described in connection with a few preferred embodiments thereof, variations and modifications may be resorted to by those skilled 'in the art without departing from the principles of the present invention. I consider all of these variations and modifications as within the true spirit and scope of the present invention, asdisclosed in the present description and defined by the appended claims.

- I claim:

l. The process of producing metallic shapes of substantially constant cross section throughout their length directly from molten metal which comprises pouring molten metal onto the'exterior surface of a continuously moving cylindrical cooling member at a point located not more than 40 degrees from the vertical center line of pair of moving surfaces, pressure means yield,-

i'ngly pressing oneof said surfaces toward the other along a. predetermined line, means for supplying molten metal to said surfaces at one side of said line, said metal then passing between whereby the separation of said surfaces against said pressure means by the metal passing between said surface controls said driving means for varying the speed of movement of said surfaces whereby to control the thickness of the metal to be formed by said surfaces.

4. In a combination of the class described, a pair of moving flangeless surfaces, pressure means yieldingly pressing one of said surfaces toward the other along a predetermined line,

means for depositing molten metal on one of said surfaces to one side of said line for free lateral spreading thereon, said metal passing between said surfaces and under the influence of said pressure means, driving means for moving said surfaces at variable speeds, and means whereby the separation of said surfaces against said pressure means by the metal passing between said surfaces controls the driving means-for varying the speed of movement of said surfaces whereby t control the thickness of the metal to be formed by said surfaces.

5. In a combination of the class described, a pair of moving flangeless surfaces, pressure means yieldingly pressing one of said surfaces toward the other along a predetermined line, means for depositing molten metal on one of said surfaces to one side of said line for free lateral spreading thereon, said metal passing between said surfaces and under the influence of said pressure means, andmeans actuated through the separation against said pressure means of said surfaces by the metal passing between said surfaces, for changing the ratio of movement of said surfaces to the deposit rate of said metal whereby to control the thickness of the metal to be formed by said surfaces.

6. In a combination of the class described, a pair of rotating flangeless rings, pressure means yieldingly pressing one of said rings toward the other. means for depositing molten metal on one of said rings to one side of their line of nearest approach, said metal passing between said rings and under the influence of said pressure means, and means. whereby the separation of said rings by the metal passing between said rings against said pressure means controls therate of rotation of said rings relatively to the deposit rate of said metal whereby to control the thickness of the metal to be formed by said rings.-

- v CLARENCE W. HAZELE'I'I.

Images