USRE21261E - Metalworking - Google Patents

Description

Nov; 14, 1939. c. w. HAZELETT METALWORK I NG Original Filed lay 3, 1933 8 Sheets-Sheet 5 CLAQENCEW HAZfiLETT l N v N TOR zjww WW ALT TO Q N 1376 TO 125591.: RE

5OURCE.

AMMEVER NOV. l4, 1939. 3, w, HAZELETT Re. 21,261

' METALWORKING Original Filed May 3, 1933 8 Sheets-Sheet 7 Cmggn'czwfiAzgm'rT I N VENTOR A-r'ro RNEJs I Reisaued Nov. 14, 1939 UNITED STATES METALWORKING Clarence W. Hazelett, Greenwich, 001111., assignor to Hazelett Metals, Inc., Greenwich, Conn, a corporation of Delaware Original No. 2,058,448, dated October 27, 1936,

Serial No. 669,216,

May 3, 1933.

Application for reissue October 26, 1938,,.Serial No. 237,116

20 Claims.

My invention relates to metalworking, and among the objects thereof are the provision of new and improved methods, the provision of new and improved apparatus, and the provision of new and improved products.

4 In the drawings accompanying this specification and forming a part of this application, I

have shown, for purposes of illustration, certain forms which my invention may assume.

In these drawings:

Figure 1 illustrates diagrammatically certain phases of my invention;

Figure 2 illustrates the action in rolling a strip directly from the molten metal;

Figure 3 shows in elevation a mill particularly suited for the purposes of my invention;

Figure 4 is a vertical section taken generally on the line 44 of Figure 3, but showing the ladle partly in section;

Figure 5 is a detail sectional view of the ladle, taken on the line 55 of Figure 4;

Figure 6 is an enlarged fragmentary vertical sectional view of the rolls and the related parts, taken on the line 5-6 of Figure 3;

Figure 7 is a horizontal sectional view, taken on the line 1-1 of Figure'6;

Figure 8' is a vertical sectional view, taken on the line B8 of Figure 6;

Figure 9 illustrates in detail the means for axially positioning the axially adjustable roll, and

for coating the flanges;

Figure 10 illustrates the system for supplying the cooling water to the rolls;

Figure 11 illustrates one method of controlling the operation of the apparatus;

Figure 12 shows an alternative form of roll construction Figure 13illustrates a roll construction adapted to produce strip of L cross section;

Figure 14 illustrates a roll construction adapted to produce strip of U cross section;

Figure 15 illustrates a roll construction adapted to produce strip of I cross section;

Figure 16 illustrates a modification of the cooling watersystem, to provide variable cooling at different points along the length of the rolls;

Figure 17 illustrates an alternative method of determining the torque being required to operate the mill Figure 18 illustrates a motor adapted to vary its speed automatically in response to the required torque; while Figure 19 illustrates a control system adapted to effect the same result.

In Figure 1 I have shown a horizontal mill I comprising a pair of horizontal rolls 2 and 3 mounted in juxtaposed parallel relation; these rolls land 3 are cooled by water delivered against the surfaces thereof through apertures in transverse ducts 4 receiving their supply through supply ducts 5 controlled by valves 6, and are driven by a motor I connected to the rolls 2 and 3 by- .any suitable transmission, indicated diagrammatically at 8.

e Variable speed of rotation of the rolls 2 and 3,

if desired, may be secured in any suitable manner, as by using for the motor I a motor which is variable in speed, or alternatively, by inserting in the drive 8 a variable speed device 9 of any suitable construction.

Mounted at the ends of the roll 2 are a pair of flanges Ill cooperating with the rolls 2 and 3 to define above the line H of nearest approach of the rolls 2 and 3 a space 12 for the reception of molten metal from a reservoir I3, to form in the space I! a molten metal pool or lake [4.

The rolls 2 and 3 being below the temperature of fusion of the metal, the metal solidifies contiguous the rolls 2 and 3, and the solidified metal is carried down to the bight II, and issues as the continuous strip S.

This strip S of course may be utilized in any desired manner, but I have in mind that it may be further processed continuously, as, for example, by the further operations illustrated in Figure 1.

That is, the strip S may be passed from the mill I through a chamber 15 containing reducing gases intended primarily to prevent the formation of oxide on the surfaces of the strip, and then may be passed through a re-rolling mill 16,

to vary the thickness of the strip, to bring the strip accurately to gauge, to change the characteristics of the strip, or to effect any other action that may be desired. From the re-rolling mill 16 the strip may pass through a normalizing furnace IT, for heat treating the strip, and then through a pickling tank l8, containing acid or other solution suitable for removing any oxidean order other than that illustrated, and also, that any or all of these operations may be omitted, or other operations added, all as may be desired, but it is to be noted that such of these operations as are included may be performed on the strip while the strip retains its original heat,

and without any re-heating, and further, that the passage of the strip immediately through the reducing chamber [5, and then through the re-rolling mill l6 before any further oxide has formed on the strip, is most eifective to completely obliterate any trace of any surface cracks which may have existed in the strip as it issued from the mill 1.

With apparatus of this type the characteristics of the strip S will depend at least in large part on the extent of the solidification contiguous the rolls 2 and 3 relative to the width of the bight ll. With the solidification entirely insufficient the molten core will fuse through the solidified faces, and the metal will pour through the bight II as a molten stream. With somewhat greater extent of solidification the relatively thicker solidified faces will be of suflicient thickness to prevent the inner molten core fusing through, and the molten core will solidify between the solidified surfaces, uniting the solidified surfaces to itself, and thus to each other, and the strip S will issue as a cast strip.

I find, however, that this characteristic continues only up to the point where the extent of solidification exceeds the width of the bight l I, and that beyond this point there ocurs this marked difference, that thereafter, by reason of the fact that the solidified metal delivered at the bight II is of greater thickness than the bight II, the strip no longer is a cast strip, but is distinctly a rolled strip, possessing the characteristics of the usual rolled strip, and other valuable characteristics in addition. a

I find that the extent of solidification contiguous the rolls 2 and 3, being dependent on the rate of solidification relative to the rate at which the strip is issued from the mill, is a result of various factors, including the nature of the metal itself, the temperature of the metal as delivered to the rolls, the length of the arc of contact of the metal with the rolls, the temperature of the rolls, and the speed of rotation of the rolls, and concurrently, that for any given metal I can maintain the desired extent of solidification by maintaining constant the relation between the various factors, and further, that I can maintain this relation constant by controlling any one or more of the factors, to compensate for variation in any one or more of the other factors.

For example, with any given metal I may maintain constant extent of solidification, despite variation in other factors, either by'coordinately varying the speed of rotation of the rolls, or by coordinately varying the rate of solidification, and I may coordinately vary the rate of solidification by coordinately varying the arc of conmetal may be varied by varying the temperature of the metal as supplied, or by preheating the metal as it is being supplied, or by heating the metal in the lake ll in any suitable manner, such as by the passage of electric current therethrough either directly, or indirectly by inducing currents therein. On the other hand, the temperature of the rolls may be varied by varying the cooling thereof, as, for example, by varying the setting of the valves 6, to vary the amount of cooling fluid supplied by the ducts l, or by varying the temperature of the cooling fluid itself, as by inter-mixing steam and water in varying proportion.

Considering the factors mentioned, the extent of solidification is'increased by decrease in the speed of rotation of the rolls, or by increase in the rate of solidification, and the rate of solidification is increased .by decrease in the temperature of the metal, by decrease in the roll temperature, and so far as I am aware, by increase in the arc of contact of the metal with the rolls.

However, any large variation in the temperature at which the metal is supplied, or in the temperature to which the rolls are cooled, is attended with considerable difliculty in practice, particularly since it seems desirable that 'the metal be supplied at a temperature considerably in excess of its melting point, and that the rolls be maintained at atemperature sufficiently low that the cooling fluid will not be so rapidly vaporized by contact with the rolls as to insulate the rolls with a blanket of relatively poor conducting vapor, and under these circumstances it appears that the control of the extent of solidification can best be accomplished either by controlling the speed of rotation of the mill or by controlling the arc of contact of the metal with the rolls.

In connection with control of the operation of the mill, I find that for any given mill, and any given metal, and any given width of the bight, the torque required to drive the mill increases with increase in extent of solidification of the metal, so that an indication of the torque required to drive the mill is an indication of the extent to which the metal is being solidified,'and operation of the mill under substantially constant torque insures solidification of the metal in substantially constant extent.

However, regardless of how the control may be accomplished, coordination of the factors governing the extent of solidification is of extreme importance, since variations will materially effeet the quality and characteristics of the product, even if small in extent, and of course, if larger, may result in appreciable damage and destruction, either by the passage of the metal through the rolls without solidification, or in the other direction, by over-solidification to an extent sufficient to wreck the mill, whereas, by suitable coordination it is possible to obtain and continuously maintain the desired condition, that is, solidification of the metal in a thickness somewhat greater than the width of the bight H, whereby the metal is rolled by the rolls 2 and 3, and the strip S issues as a rolled strip. I 1

In Figure 2 I have illustrated the actionavhich occurs in this respect, showing the rolls land 3, the molten metal lake M in the space I! between the rolls 2 and 3 and the flanges Ill (see Fig. 1), and the solidification of the metal contiguous the rolls 2 and 3, into the strips 23, increasing progressively in thickness until at their meeting point 24 they are of a combined thickness materially greater than the width of the. bight H, and the further actionof the rolls 2 and 3 is distinctly and definitely a rolling action, to reduce the thickness of the strips 23 to that defined by the width of the bight II, so that, as is to be expected from the fact that the strip is rolled, the strip S issues in a thickness slightly greater than the width of the bight II, and further, by the extrusion action consequent to the rolling action, at a linear speed materially in excess of the peripheral speed of the rolls 2 and 3.

From the foregoing it will be apparent that.

metal from. a molten state may be formed directly into a solid continuous strip, having the characteristic of a rolled strip, and certain other valuable characteristics in addition, and further, that this strip may be treated and fabricated, even into a finished article, by a succession of instrumentalitles operating continuously, while the metal still is hot.

In Figures 3 through 11 I have shown an embodlmentof means for carrying out this process.

This embodiment comprises a horizontal mill 25 having a frame 26in which is mounted a first pair of bearings 21 carrying a first roll shaft 26 on which is mounted a fir t roll 29.

Also mounted in the frame 26 is a second pair of bearings 39, carrying a second roll shaft 3|, on which is mounted a second roll 32, and this second pair of bearings 39 is mounted in the frame 26 for reciprocation toward and from the first pair of bearings 21, to reciprocate the shaft 3| and roll 32 toward and from the shaft 28 and roll 29, to vary the spacing between the rolls 29 and. 32, and the width at the bight 33.

The reciprocation ofeach bearing 39 is controlled by a screw 34 coacting with a nut '35 mounted in the frame 26; each-screw 34 carries at its foot a swivel connection 36, connecting the screw with the corresponding bearings 39, and at its head a pointer 31, cooperating with a dial 38 on the frame 26 to indicate at all times the position of the corresponding bearing 39.

Mounted between each bearing 21 and the con tiguous bearing 39 is a coil spring 39, serving to hold the bearings and shafts and rolls in separated position, prior to the introduction of the metal between the rolls.

The shaft 28 is driven from an electric motor 49 through suitable reducing gearing 4| connected to a pinion 42 meshing with a gear 43 mounted on the shaft 28, and the shaft 3| is driven from the shaft 29 by means of inter-meshing gears 44 and 45 carried respectively by the shaft 29 and the shaft 3| and provided with elongated teeth adapted to remain in mesh for all permisible spacings of the rolls 29 and 32.

Mounted on the roll 32 are a pair of flanges 46 secured in position by means of bolts 41 extending through the flanges into the roll, and these flanges 46, together with the rolls 29 and 32, form the space 49 in which is retained the molten metal lake 49.

I prefer to form each roll of homogeneous material, without surface chilling or case hardening, and of a thickness not less than twice the maximum thickne s of strip intended to be rolled, and then, to prevent contact between the male roll 29 and the flanges 46 acting to gouge splinters from the flanges 46, I prefer to make the flanges 46 of a material definitely softer than the material of the roll 29. To secure uniform gage across the width of a strip I find it desirable to concave one or both of the rolls 29 and 32, as shown in Figure 7 in connection with the roll 29.

In this particular embodiment of my invention the molten metal is supplied to the lake 49 from a heated ladle or furnace 59.

The particular furnace herein disclosed comprises a body 5| of refractory material, in the lower portion of which is a core 52 which is also of refractory material and is of a size to define between itself and the body 5| a U-shaped passage 53 communicating at both upper ends with the open interior 54 of the furnace 59. Extending through the center of '--the refractory core 52 is the center leg 55 of the core 56 of a transformer, the primary winding of which, not shown,

is connected to any suitable source of alternating current, and the secondary of which is constituted by the metal within the passage 53, so that the flow of current in the primary of the transformer induces a current in the metal within the passage 53, to heat this metal, and thus, by convection, to heat the entire metal within the furnace 59.

The furnace 59 is plvotally supported on the frame 26 of the mill 25 by means of a pair of ears 51 carried by the furnace 59 and connected by pivot pins 56 to cooperating ears 69 carried by the upper plate 69 of the mill frame 26, and the furnace 59 delivers its metal through a spout 6| which is positioned intermediate the ears 51 and pours into a trough 62 from which the metal is delivered to tor 63.

The furnace is tilted by means of a hydraulic ram 64 having its cylinder 65 pivoted at 66 to lugs 61 on the base 69 of the mill frame 26, and having its piston 69 pivoted at 19 to lugs 1| on the frame of the furnace 59.

The distributor 63, into which the molten metal is discharged by the trough 62, is disposed in the space 49 between the rolls 29 and 32, intermediate the flanges 46, and with its bottom 12 lying below the normal surface of the molten metal lake 49, and discharges the metal into the lake 49 through intermediate apertures 13 and end apertures 14, all disposed in the bottom 12, midway between the rolls 29 and- 32.

The distributor 63 acts as a skim box to skim from the molten metal any dross which may the lake 49 through a distribucome down the trough 62 and then, by introducing the metal into the lake 49 below the surface of the lake, prevents the formation of any further dross, and in this way effectively prevents the introduction of any dross into the lake 49, and therefore, into the strip produced by the mill.

The introduction of the metal into the lake 49 below the normal surface of the lake also serves to introduce the metal quietly, and without surges, and this effect is augmented by the further fact that the distributor 63, and the metal contained therein, operate as a baflle, to damp out the kinetic head present in the metal as the metal comes down the trough '62, so that the metal enters the lake 49 almost solely in response to gravity, and therefore, quietly, and with no particular force or velocity, and in this connection I find it desirable that the total head of the metal entering the lake shall be less than the head of the lake. Further, the positioning of the apertures 13 and 14 midway between the rolls 29 and 32 introduces the metal into the lake 49 at that point where the lake is of the greatest depth, and theentering metal is least likely to contact with the solidified metal.

Under these circumstances the distributor 63 not only acts to insure purity of the metal within the lake 49, but also, to prevent any flow or eddying of the metal within the lake 49, likely to cause any irregularity in the solidification of the metal contiguous the rolls 29 and 32, or in any way interfere with uniformity of the solidification of the metal.

However, in order to assure further against the presence of dross in the metal of the lake 49, I may envelope the surface of the lake 49 in a reducing atmosphere, as by means of ducts 15 disposed on the two sides of the distributor 63, connected to a suitable source of reducing atmosphere, and provided with apertures by which the reducing atmosphere is discharged onto the surface of the lake 49, as indicated in Figure 6.

Under many circumstances I find it desirable that the metal shall be delivered to the lake 49 at a temperature perhaps '15 degrees Fahrenheit in excess of the melting point of the metal, in order that any trapped gases may have ample opportunity to escape, before the metal solidifies; I may achieve this result by delivering the metal to the trough 62 at a correspondingly high temperature. In this connection it may be noted that I may preheat the trough 62, or the distributor 63, or both, as by means of heaters 16 and/or 11, positioned respectively above the trough 62 and above the distributor 63, connected to a suitable source of gaseous fuel, and directing their flame respectively on the trough 62 and the distributor 63.

In order to prevent penetration of the metal of the lake 49 between the roll 29 and the flanges 46 carried on the roll 32, I find it desirable to reduce the spaces between the roll 29 and the flanges 46 to a minimum, and to that end, to center the roll 29 accurately between the flanges 46; as a matter of fact, this is particularly important when the metal is introduced at a temperature materially above its melting point, by reason of the rapid increase in the facility with which the metal penetrates, as the temperature is raised.

To this end I mount the rolls 29 and 32 fixedly on the shafts 23 and 3|, support the shaft 28 against all axial movement, and then mount the shaft 3| for axial adjustment, as may be required to effect the desired centering of the roll 29 relative to the flanges 46.

Each of the rolls 29 and 32 is held against rotation on its shaft 28 or 3| by means of a key 16 reeeived'in cooperating keyways l9 and disposed respectively in the shaft 28 or 3| and the roll 29 or 32. In assembling either roll upon its shaft the key 18 is placed in the shaft keyway 19, and the roll, positioned with its keyway 89 in alinement with the key 18, is moved longitudinally along the shaft until an annular roll shoulder 8| abuts an annular shaft shoulder 82, whereupon the roll is held against further axial movement in that direction. At this stage the key 18 is fully engaging in the cooperating keyways l9 and 89, holding the roll firmly against any rotation relative to its shaft. 'I'hereupon the segments of'a segmental ring 93 are seated in an annular shaft recess 94, but projecting radially to overlie an annular roll shoulder 85, whereupon the roll is held against retrograde movement longitudinally of the shaft, and therefore, against any relative movement axially of the shaft.

A resilient split ring 66 is then placed in position encircling the segments of the segmental ring 83, to lock these segments against any possible displacement.

The shaft 23 is held against axial movement relative to the mill frame 26 by means of collars 81 interposed between annular shoulders 98 on the shaft 28 and the bearing rings 89 flxed in the mill frame 26.

The means for effecting longitudinal adjustment of the shaft 3| in the mill frame 26, and for holding the shaft 3| in its adjusted position, comprises thrust rings 90 held against rotation by pins 9| extending into the mill frame 26 and bearing against cooperating thrust rings 92 flanking the flanges 46 which in turn flank the two sides of the roll 32; the thrust rings 90 are moved along the axis of the shaft 3| to axially position the shaft 3| and the roll 32, and are held in adjusted position, by encircling rings 93 screwthreadedly engaging the thrust rings 99 and bearing against the sides of the mill frame 26.

In operation, the roll 29 being locked to the shaft 26, and the shaft 28 being fixed against longitudinal movement relative to the mill frame 26, and the roll 32 being locked to the shaft 3|, the adjustment of the flanges 46 relative to the roll 29 is eifected by rotation of the encircling rings 93, to project one of the thrust rings 99 and retract the other thrust ring 9|), until the shaft and roll and flange assembly 3|-'3246 has been moved to the desired position, with the roll 29 accurately centered between the flanges 46, and the shaft and roll and flange assembly 3l 32-46 is held in this position, with the flanges 46 accurately centered on the roll 29, by the irreversibility of the engagement of the encircling rings 93 with the thrust rings 99.

Further to prevent entrance of metal between the roll 29 and the flanges 46, I may apply oil or similar material to the ends of the roll 29, or may provide an air blast blowing out from the spaces between the roll 29 and the flanges 46.

With the construction herein described, the flanges 46 exert an additional cooling effect adjacent the edges of the strip, which tends to cause at the edges of the strip an increased solidification of the metal relative to the extent of solidification of the metal centrally of the strip. This not only tends to produce lack of uniformity in the strip, but further, tends to form adjacent the flanges 46 masses of solidified material which will accumulate to a considerable size before they pass between the rolls 29 and 32, and then, in passing between the rolls 29 and 32, will exert a pressure on the rolls which may crack a roll, break a bearing, or cause other injury to the mill, and to guard against this accumulation of solidified metal adjacent the flanges 46 I find it desirable to provide additional traction at the ends of the rolls; I find that this may be done by roughening the edges of the rolls 29 and 32, but roughening the edges of the rolls 29 and 32 produces a corresponding roughening of the surface of the strip, which in many instances is objectionable, wherefore I prefer to provide this additional traction by having the inner faces of the flanges 46 relatively rougher, as indicated at 94 in Figure 6.

To the same end I find that it also is desirable under certain circumstances to coat the inner faces of the flanges 46 with material which will prevent freezing of the metal to these inner faces of the flanges 46, and to this end I provide means for continually applying such material to the inner faces of the flanges 46, as shown particularly in Figure 9, wherein I have disclosed a holder 95 in which is positioned a graphite block 96 spring pressed against the inner face of the flange 46 by means of a coil spring 91 interposed between the base 99 of the block receiving recess 99 of the holder 9' and the base IIIII of the block 96.

However, I prefer also to provide means to compensate for the increased cooling at the edges of the rolls, and I find that I may do this conveniently by forming the end apertures II of the distributor 83 of greater size than the intermediate apertures .13, so that a greater proportion of the molten metal is introduced into the lake I at the ends of the lake, adjacent the flanges l9, and the lake is additionally heated at the ends thereof, so that additional cooling is required adjacent the flanges 49.

I Dr I may accomplish this compensation by undercutting one or bothof the rolls 29 and 22, as indicated at IIII on the roll 29, whereby the strip is formed of increased thickness at its edges, and the increased cooling adjacent the flanges 46 is absorbed.

While either of thesemethods is satisfactory,

in actual practice I prefer to accomplish the compensation by the coordinate use of both methods, as herein illustrated.

Finally, Just below the night 33 I provide scrapers I 92, bearing against the rolls 29 and 32 and effective to separate the strip from either of the rolls to which it may tend to adhere.

To cool the rolls 29 and 92 I'provide two series of arcuate pipes I93 extending beneath and to the rear of the rolls, apertured to spray cooling water against the surfaces of the rolls, and fed from headers III to which the cooling water is supplied by supply pipes N; to carry away the cooling water I overlie these portions of the rolls 29 and 92 with housings II" in which the cooling water is collected, and from which the cooling water is discharged through waste ducts I08, and I conveniently support these housings III by attaching their lower ends to cross bars I99 supported from the bearings 21 and 30.

The housing II" for the roll 29 also cooperates with the distributor 62 to removably support the trough 92;

Under certain circumstances there is a tendency for vapor from the cooling water to adhere to the surfaces of the rolls, and to form on the surfaces of the rolls a sheathing blanket insulating the rolls from the subsequent jets of cooling water, and therefore, reducing the. cooling action of the subsequent jets; to overcome this tendency I may provide wipers wiping the rolls between successive rows of jets, such as the wipers IIII shown in Figure 6 as supported from the housings I91 and as wiping the rolls-subsequent to the first two rows of jets.

To this same end I prefer to maintain the rolls under 400 degrees Fahrenheit.

The supply of cooling water may be controlled ,manually by a manually operated valve I I I interposed in a main supply duct I96 from which the branch supply ducts I05 are supplied, but I prefer to use this manually operated valve III merely as a shut-off valve, to completely shut off the supply of cooling water when the mill is not in operation, and during operation of the mill to control the supply of cooling water to the rolls 29 and 32 by control valves 2 interposed in the branch supply ducts I05 and actuated automatically in response to the temperature of the rolls 29 and ,32.

Each valve H2 is provided in its web with a valve seat H9 in which seats a valve head Ill, but the web of the valve also is prov ded with an aperture II5 acting as a by-pass to permit a base quantity of cooling fluid to flow continuously, so that raising the valve head Ill does not institute the flow of cooling water,.but merely increases the volume in which the cooling water is furnished.

It will be understood that under these circumstances the base amount of cooling water, permitted to flow by the by-pass aperture H5, is

made somewhat less than the amount required to cool the roll, and the additional cooling water requisite for proper cooling of the roll is then illlrnished by intermittent opening of the valve To make this control automatic I provide for each valve II2 a control comprisinga thermocouple III disposed in contact with the corresponding roll at a point above the area. where cooling water is sprayed onto the roll, and therefore, responsive at all times to the lowest temperature obtaining in the roll.

The conductors Ill and m leading from the thermo-couple II are connected to the two ends of the coil II9 of a relay I arranged upon sufficient energization of the coil II9 to close the relay switch I2I and complete the circuit through a solenoid I22 whose armature I2! is connected to the valve head III, to open the valve I I2 whenever the solenoid I22 is energized, and to hold the valve II2 open so long as the solenoid I22 continues to be energized, or in other words, so long as the current in. the coil- II9 of the relay I29 is sufllcient to maintain the relay switch I2I in closed position, and therefore, since thecurrent in the coil H9 is the current of the thermal circuit, and the current of the thermal circuit is responsive to the temperature of the thermocouple, so long as the minimum temperature of the roll exceeds a predetermined amount. Then when the temperature of the roll falls below this predetermined amount, the valve 2 closes, to cut off the additional cooling water, and remains closed until the temperature of the roll again exceeds the predetermined amount, whereupon the valve I I2 again opens, to supply additional cooling water, to reduce the temperature of the roll, and the cycle is repeated.

While I have shown this cooling water control only in connection with the roll 32, it will be understood that it is employed also in connection with the roll 29, and further, that the control employed in connection with the roll 29 is in all respects a duplicate of the control disclosed in connection with the roll 32.

In Figure 11 I have indicated more or less diagrammatically one arrangement for controlling the general operation of the mill.

This arrangement contemplates driving the rolls 29 and 32 by a substantially constant speed motor such as the shunt motor I24, so that the current required by the motor is responsive substantially directly to the torque required to operate the mill, and therefore, to the torque required to roll the strip under the conditions of extent of solidification then existing, whereby an draulic pressure, or alternatively, to a waste duct I20.

This arrangement also considers that for any given metal, and any given width of the bight, with constant speed of rotation of the rolls, the extent of solidification may be controlled by controlling the depth of the lake 49, to control the arc of contact of the metal with the rolls.

And with regard to these circumstances, the operator actuates the control valve I26 in accordance with the indications of the ammeter I25, raising the ladle faster if the current required by the motor I24 decreases, to increase the depth of the lake and the extent of solidiflcation, and decreasing or discontinuing the raising of the ladle 50 if the ammeter I25 indicates increase in current to the motor I24, thus to lower the height of the lake 49, and to decrease the extent of the solidification.

In this connection, I find that for metals such as zinc, brass, and steel, it is desirable that the power used by the mill shall be not less than one horse power per foot of width of strip per foot per minute peripheral speed of the mill.

.Considering that the ammeter I25 indicates immediately any change in the current required by the motor I24, and therefore, any change in the extent of the solidification, it has been found that with this arrangement an experienced operator may maintain the extent of solidification of the metal well within the limits of the range over which satisfactory sheet is produced by the mill.

This arrangement, with its manual control of the tilting of the furnace 50, also is particularly advantageous in connection with operation of the mill to produce a continuous sheet requiring more metal than can be contained in the furnace 50 at a single charge, so that the continued operation of the mill requires refilling of the furnace 50, and thereby, rapid movement of the furnace 50 to retract it into position toreceive a further charge, and to return it to position to resume pouring of metal into the trough 62, before the level of the lake 40 has decreased below the minimum level at which the mill continues to produce sheet of the desired characteristic. I

In Figure 12 I have shown an alternative roll construction comprising rolls I each having an inner core I3I surrounded by an outer shell I32 having an internal diameter considerably in excess of the outside diameter of the core I3I and supported by a supporting roller I33 mounted in any suitable manner from the frame 26 of the mill 25. It will be understood that the shell I32 and the core I3I are in engagement at the bight 33, and in order to drive the shell I32 positively from the core I3I, the core I3I and the shell I32 may be provided respectively with external teeth I34 and internal teeth I35, arranged to mesh at the point of engagement of the shell and the core, at the bight 33, or the teeth I34 and I35 may be omitted.

With this construction the shell may be cooled both externally and internally by cooling water issuing from nozzles I36 and I3'I located respectively outside the shell I32 and in the space between the shell I32 and the core I3I, at a point directly opposite the point of engagement of the core I3I and the shell I32. The flow of cooling fluid to the nozzles I36 and I31 may be controlled manually by valves I36 located in the supply ducts I39, or may be controlled automatically, as hereinabove described.

By means of this construction the rolls I30 present substantially solid and unyielding surfaces to the metal at the bight 33, yet at the same time are constructed to facilitate cooling of the shell, both by reason of the ability to cool both internally and externally, and also, by reason of the fact that the shell, being solidly backed by the core at the point of stress, may be relatively thin, to facilitate the cooling thereof.

This construction also has the further advantage, that the relatively inexpensive outer shells may be replaced without replacement of the entire roll structure. I

In Figures 13 through 15 I have shown alternative shapes of forming rolls, for rolling strip of various cross sections.

The roll I40 of Figure 13 is provided with a V-shaped recess HI, and with flanges I42, and the cooperating roll I43 is provided with a V-shaped projection I44, cooperating with the V-shaped recess I4I of the roll I40 to define a V-shaped opening I45 at the bight of the rolls, so that the rolls of Figure 13 will produce a strip of V-shaped cross section.

In Figure 14 the roll I46 is provided with a relatively flat central portion I41, and at the edges thereof, just within the flanges I49, with relatively deep recesses I46, and the cooperating roll I50 is formed with a flat face I5I of a width substantially equal to the entire distance between the flanges I45, whereby there is defined at the bight of the rolls a U-shaped space I52, and the rolls of Figure 14 produce a strip of U-shaped cross section.

In Figure 15 the roll I53 is provided with a relatively flat central section I54, and with relatively deep recesses I55 on each side thereof, just within the flanges I56, and the cooperating roll I5I also is provided with a relatively flat central portion I58 flanked by relatively deep recesses I55, so that the rolls of Figure 15 define at the bight an I-shaped space I60, and produce a strip of I-shaped cross section.

It will be understood of course that the strip may be formed of any other desired cross sec-'- tion, merely by proper configuration of the surfaces of the rolls, and accordingly, that the sheet, V, U, and I cross sections herein shown, are

merely illustrative ofthe cross sections which can be produced.

In Figure 16 I have shown means for cooling the rolls in varying degree at various points along the length of the rolls, and I find this desirable under certain circumstances, and with certain types of rolls, for example, in order to control the rolls against undue distortion, or alternatively, to compensate for the additional cooling effect of the flanges by decreasing or omitting the cooling of the rolls adjacent the flanges. The particular means disclosed in Figure 16 comprises a cooling water manifold I6I extending parallel to the roll I62, receiving fluid from a mainduct I63 under control of a manual valve I64, or alternatively, under control of an automatic control, as hereinabove described, whichever may be desired, and then discharging the cooling fluid against the roll I62 through a plurality of branch ducts I65 spaced along the length of the manifold I6I and each controlled by an individual branch valve I66, whereby the relative amount of cooling water in the various branch ducts I65 may be controlled and proportioned as may be desired.

In controlling the operation of the mill manually I may substitute for the ammeter indication -short arm I13 of a lever I14 fulcrumed at I15 and having its long arm I16 connected by a link I11 to the short arm I18 of a lever I19 fulcrumed at I89 and having its long arm III engaging a reciprocating bar I82 carrying a rack I83 which cooperatively engages a pinion I84 mounted on a shaft I85 to which is secured an indicator arm I86 moving over the scale I81 of an indicator dial I88. Depression of the free end "I of the base I69 is opposed continually, in constantly increasing amount as the free end I'll is depressed, by any biasing means suitable for that purpose, such as a biasing means utilized for that purpose in an ordinary scale.

n the other hand, while the coordination of the factors governing the relative extent of solidification 01' the metal, and the operation of the mill, and the characteristics of thestrip, may be controlled manually, and by control of the depth of the lake responsive to an indication of the torque required to' operate the mill, the coordination also may be eifected automatically, and in this connection, may be efiected conveniently by controlling the speed at which the mill operates.

For example, I may drive the mill by the differential series field compound motor I89 disclosed in Figure 18 and comprising an armature I 99 acting under the influence of the field resulting from the combined action of a shunt coil I9I and of a series coil I92 wound to set up a field opposite in direction to the field generated by the shunt coil I9I, whereby, increase in current through the motor I89, resulting from increase in torque. required to operate the mill, caused by excessive extent of solidificatiom, by increase in the reverse series field automatically will decrease the resultant field and increase. the speed of the motor I89 and of the mill, to decreasethe -extent of solidification, whereas decrease in ,torgue required to drive the mi l l ,;=,resulting from decrease in the extent of solidification, will decrease the current througnthe motorv I89, to decrease the field generated by the series coil I92, to in crease the resultant field, and thus ,to decrease thespeed of the motor I89 and of the mill, and

thereby, to increase the extent of solidification. The extent of the action-of the series field of course will be limited, as is well known in the art, to prevent preponderance of the series field under any operating conditions.

With a motor of this type, eifecting control automatically, it is necessary only to coordinate initially for the nature of the metal and the width of the bight, after which the motor I89, properly constructed, will maintain the coordination automatically.

However, under many circumstances it is not desirable to vary the speed of operation of the mill, but on the contrary, is desirable to maintain the mill at constant speed, and to control some other factor governing the extent of solidification of the metal, and in those circumstances 292 and 293 and 294 to a reversing and control switch 295 which in turn is connected to the line wires I98 and I99 and 299 by means of connecting conductors 298 and 291 and 298 and is operative in its upper position to connect the control motor 29l for operation in one direction, and in its lower position to connect the control motor 29l for operation in the reverse direction, as will be understood from the diagram of con nections.

Mounted on the shaft of the control motor 29I are three slip rings 299 and 2l9 and 2 I l, connected to the rotor winding as is well known in the art, and engaged by brushes, not shown, connected to conductors 2I2 and 2I3 and 2 leading to resistances 2I5 and 2I6 and 2H connected together at their opposite ends by a T- conductor 2I8, whereby the control motor 29l operates normally with the resistances 2I5 and 2I6 and 2H interposed in the armature circuit. However, leading from the conductors 2I2 and 2 I3 and 2 connecting the slip rings 299 and 2l9 and 2 to the resistances 2I5 and 2I6 and 2| 1 are conductors 2l9 and 229 and 22I leading to a normally open switch 222 adapted to connect together the conductors 2l9 and 229 and 22I, to short circuit the resistances 2I5 and 2I6 and 2I1, to remove these resistances from the armature circuit of the motor 29I, thus to short circuit the armature of the motor 29I, to correspondingly increase the speed. of the motor 29I, whenever the speed switch 222 is closed.

The control switch 295 is moved to forward position by means of a forward solenoid 223, and to reverse position by means of a solenoid reverse 224, and the speed switch 222 is moved to closed position by a solenoid 225, while the switch 295 includes also an auxiliary switch 226, comprising a contact arm 221 adapted to engage with a forward contact 228 when the control switch 295 is in forward position, and with a reverse contact 229 when the control switch 295 is in reverse position.

Interposed in the conductor I96 from the mill motor starter I91 to the mill motor I93 are a series of relays 239,23I, 232, 233, 234, and 235, responsive to current flowing in the conductor I96, and set to operate at progressively increasing values, in the order named, the relays 239 and 23I and 233 being in the nature of overload relays, each opening on the passage of current in excess of the value predetermined for that relay, and the relays 232 and 234 and 235 being in the nature of under-load relays, each closing on the passage of current of a value greater than that predetermined for'that relay.

Under these circumstances, with the mill motor starter I 91 in the oiT position, the relays 239 and 23l will be in closed position, the relay 232 will be in open position, the relay 233 will be in closed position, and the relays 234 and 235 will be in open position, and this condition will continue until the current in the line I98 reaches a value in excess of the predetermined value at which the relay 230 will operate.

Accordingly, when the mill motor starter I91 is closed current will flow not only to the mill motor I93 but also from the main conductor I95 through conductors 235 and 231, the switch of the relay 230, conductors 238 and 239, the coil 225 of the speed switch 222, and conductors 240 and 2 and 242, back to the main conductor I95, thus energizing the coil 225, to close the speed switch 222, to short circuit the resistances 2I5 and 2I5 and 2I1 in the armature circuit of the control motor 20I, to connect the control motor 20I for operation at the maximum speed. Simultaneously, the relay 23I also being closed, current will flow from the main conductor I95 through conductors 243 and 244, the forward coil 223 of the control switch 205, conductors 245 and 245, the switch of the relay 23I, conductors 241 and 248, and conductor 242, back to the main conductor I95, to energize the forward coil 223 of the control switch 205, to move the control switch 205 into the forward position; and to connect the control motor 20I to operate forwardly, and by reason of the fact that the speed switch 222 is closed, to operate at maximum speed. Directly the control switch 205 has moved into the upper or forward position the switch arm 2210f the auxiliary switch 225 will engage the forward contact 228, and this will close a second circuit through the forward coil 223 of the control switch 205, extending from the main conductor I95 through the conductors 243 and 244, a the coil 223 of the control switch 205, the conductor 245, a conductor 249, the switch of the relay 233, a conductor 250, the auxiliary switch contact 228 and the auxiliary switch arm 221, a conductor 25I, and the conductor 242, back to the main conductor I95.

As the current in the conductor I95 increases, the relay 230 will open, to open the circuit through the coil 225 of the speed switch 222, to interpose the resistances 2I5 and 2 I5 and 2I1 in the armature circuit of the control motor 20I, to reduce the speed of operation of the control motor 20I. Then, as the current in the conductor I95 increases further, the relay 23I will open, to interrupt the circuit through the forward coil 223 of the control switch 205 by way of the switch of the relay 23I, but this will be ineffective, by reason of the fact that the circuit through the coil 223 is also completed through the switch of the relay 233. As the current in the main conductor I95 increases still further, the relay 232 will operate to close its switch, but this also will be inefiec tive, because of the fact that by the conductor 252 the relay 232 is in series with the auxiliary switch 225 of the control switch 205, and that the arm 221 of the auxiliary switch 225 is in forward position, in engagement with the forward contact 228, rather than in reverse position, in engagement with the reverse contact 229, to which the switch of the relay 232 is connected.

However, as the current in the main conductor I95 increases still further, it reaches the value predetermined for the relay 233, and the relay 233 opens, interrupting the last circuit through the forward coil 223 of the control switch 205, to permit the control switch 205 to return to neutral position, under the action of biasing means of any suitable type, not shown. It will be noted, however, that this still does not bring the switch arm 221 of the auxiliary switch 225 into contact with the reverse contact 229, so that the fact that the switch of the relay 232 is closed still is of no 7 consequence.

However, as the current in the main conductor I95 increases still further, the relay 234 operates, to close its switch, and a circuit is then completed from the main conductor I95 through the conductor 243, a conductor 253, the reverse coil 224 of the control switch 205, conductors 254 and 255, the switch of the relay 234, a conductor 255, and the conductors 2H and 248 and 242, back to the main conductor I95, to energize the reverse coil 224 of the control switch 205, to move the control switch 205 into reverse position, to connect the control motor 20I for operation in the reverse direction. When the control switch 205 is thus moved to reverse position the switch arm 221 of the auxiliary switch 225 contacts the reverse contact 229, and this completes a second circuit through the reverse coil 224 of the control switch 205, extending from the main conductor I95 through the conductors 243 and 253, the reverse coil 224 of the control switch 205, the conductor 254, a conductor 251, the switch of the relay 232, the conductor 252, the contact 22 9, the auxiliary switch arm 221, and the conductors 25I and 242, back; to the main conductor I95.

If the current in the main conductor I95 con tinues to increase, and reaches the value predetermined for the relay 235, the switch of the relay 235 will be closed, to complete a circuit from the main conductor I95 through the conductor 235, a conductor 258, the'switch of the relay 235, a conductor 259, the conductor 239, the coil 225 of the speed switch 222, and conductors 240 and 2 and 248 and 242, back to the main conductor I95, to again energize the coil 225 of the speed switch 222, to close the speed switch 222, to short circuit the resistances 2I5 and 2I5 and 2|1 in the arma ture circuit of the control motor 20I, to set the control motor 20I operating again at full speed, but this time in the reverse direction.

However, if the current in the main conductor I95 decreases instead of increasing, it first will drop below the predetermined value for the relay 234, and the relay 234 will open, to open the circuit through the reverse coil 224 of the control switch 205 by way of the switch of the relay 234,

but this will be immaterial, since an alternative circuit is closed through the reverse coil 224 of the control switch 205, by way of the switch of the relay 232. As the current in the main conductor I95 decreases further, the switch of the relay 233 will close, but this also will be immaterial, because the switch of the relay 233 is in series with the forward contact 228 of the auxiliary switch 225, and the switch arm 221 of the auxiliary switch 225 is in engagement with the reverse contact 229 rather than with the forward contact 228.

However, if the current decreases still further, the relay 232 will operate, to open its switch, and this will break the second circuit through the reverse coil 224 of the control switch 205, and the control switch 205 will return to neutral position, to disconnect the control motor 20I.

Thereafter, increase in current'in the main conductor I95 will repeat the cycle heretofore described, while further decrease in current in the main conductor I95 will again close the switch of the relay 23I, to again close the circuit through the forward coil 223 of the'control switch 205, to operate the control motor 20I in the forward direction, until the current in the main conductor I95 exceeds the predetermined value for operation of the relay 233, either with or without operthe value predetermined for operation of the relay 230.

Under these circumstances we have the situation that when the current to the mill motor I93 falls below the value predetermined for the relay 23I the control motor 2III operates in a forward direction until such time as the current to the mill motor I93 exceeds the value predetermined for the second succeeding relay 233, and then rests, until the current to the mill motor I93 either again drops below the value predetermined for the relay 23I, in which case this cycle is repeated, or rises above the value predetermined for the relay 234, in which case the control motor ZIII is operated in the reverse direction, until the value of the current to the mill motor decreases to below the value predetermined tor the intermediate relay 232, whereupon the control motor again rests, until the current to the mill motor I93 again rises above the value predeterminedfor the relay 234, in which case the control motor is again actuated in the reverse direction, or alternatively, again falls below the value predetermined for the relay 23I, in which case the control motor 2III is again actuated in the forward direction. With this addition, that upon excessive departure from normal the relays 230 and 235 are brought into play, to short circuit the resistances in the armature circuit of the control motor 2M, to increase the speed of the control motor 20I, to expedite the return to normal.

I have heretofore pointed out that the torque required to drive the mill follows the extent of solidification relative to the spacing of the rolls, and of course the current required by-the mill motor I93 follows the torque required to drive the mill, wherefore, the current in the main conductor I96, acting on the relays 230 and 23I and 232 and 233 and 234 and 235, with any given metal, and with any given spacing of the rolls, and withcalibration accordingly, follows the extent of solidification of the metal, and the extent of solidification of the metal therefore may be maintained constant automatically, merely by suitably connecting the control motor 2M to any one or more means controlling one or more of the factors governing the extent of solidification.

For example, I may connect the control motor 2III through suitable gearing to the furnace 50, to control the pouring of the metal from ,the furnace 50 into'the trough 62, or I may connect the control motor 2M to the valves II2 controlling the supply of cooling water to the rolls, but whatever arrangement is employed, the control means of Figure 19, properly set to correspond to the nature of the metal being worked, and the width the bight, will automatically coordinately vary any one or more of the factors governing the extent of solidification, automatically to maintain constant the characteristics of the continuous strip emerging from the mill.

And of course, while I have described the apparatus herein illustrated with particular reference to the combination where the extent of solidification is greater than the width of the bight of the rolls, so that a rolled strip is secured, the apparatus herein shown may in large part be utilized as well for strip having other character istics, such as that produced when the extent of solidification is not greater than the width of the bight, and the strip is cast.

However, operating the mill to produce a rolled strip, I obtain strip far superior to chemically identical strip in which solidification preceded mechanical working by any usual time or temperature interval.

One plausible explanation of these facts is that at the instant of solidification of any molten metal the rate of growth of crystalline structure,

expressed in terms of fixity of relations between individual atoms or groups of atoms, is a maximum at' the outset, but decreases very rapidly. This is believed to hold true with respect to both time and temperature. In other words, the rate of the growth of crystalline microstructure is a function of both temperature and time.

The process disclosed causes mechanical distortion to operate on grain size at times and temperatures approximating those of the instant of solidification much more closely than in any other process of which I am aware. Furthermore, when solidification completes the bridging of the space between the two rolls, as at 24 in Figure 2, and every portion of the metal is instantaneously subjected to mechanical deformation, the beginning of deformation not only is coincident with the first occurrence of ability to receive mechanical stress, but acts in the first instance on a body of material having a steep temperature gradient. from the center to each' cal deformation by later rolling, either hot or cold, suifer the major part of the mechanical deformation throughout the entire rolling action, and thereafter no temperature gradient approximating the initial gradient ever can be obtained. Whether the foregoing theory is correct or not, the fact is that material prepared as herein disclosed has ductility and homogeneity superior to the identical metal either hot rolled or cold rolled, and to such an extent as to permit a significant extension of the fields of use of such materials. For instance, brasses prepared in this way can be subjected to drawing operations more severe than were previously possible, and after drawing exhibit a much higher freedom from cracking, and a much superior surface finish.

In the preparation according to the invention of alloys capable of hardening and tempering by heat treatment, it is possible to cool the outer surfaces below one or more of the transformation points of the material during the initial formation of the strip. Obviously this amounts to simultaneous solidification, temperature transformation, and mechanical deformation, thus accomplishing in a single momentary operation what heretofore has required at least two sepabe obvious that the disclosure herein is illustrative only, and that my invention is not limited thereto.

Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed,,I declare that what I claim is:

1. Ihe method of producing solid metal of substantially constant cross section throughout its length directly from a mass of molten metal which comprises establishing a bath of molten metal between a pair of adjacent and operatively associated rolls; providing a dam at each end 0! the rolls to maintain the molten metal in said bath; maintaining said molten metal to a selected height in said bath; rotating said rolls to cause the ejection of solidifiedmetsl from the bight of the rolls; and adding more heat to the zones adjacent to the dams than to the intermediate zones to control the thermal conditions so that the temperature 0! the solidified metal at the bight of the rolls is substantially the same in the zones adjacent to the dams and the intermediate zones of the molten bath.

2. The method oi producing solid metal oi sub stantially constant cross section throughout its length directly from a mass of molten metal which comprises establishing a bath oi molten metal between a pair of adjacent and operatively associated rolls; providing a dam at each end of the rolls to maintain the molten metal in said bath; maintaining said molten metal to a selected height in said bath; rotating said rolls to cause the ejection of solidified metal from the bight of the rolls; and controlling the thermal conditions so that the temperature oi the solidified metal at the bight oi the rolls is substantially the same in the zones adjacent to the dams and the intermediate zones by regulating the amount oi heat supplied to the various zones 0! the bath.

3. The method of producing solid metal of substantially constant cross section throughout its length directly from a mass oi molten metal which comprises establishing a bath of molten metal between a pair of adjacent and operatively associated rolls; providing a dam at each end of the rolls to maintain'the molten metal in said bath; maintaining said molten metal to a selected height in said bath; rotating said rolls to cause the ejection of solidified metal from the bight of the rolls; and controlling the thermal conditions so that the temperature of the solidified metal at the bight oi the rolls is substantially the same in the zones adjacent to the dams and the intermediate zones of the molten bath; the said controlling operation involving introducing a larger amount of molten metal to those regions 01' the bath adjacent to the dams at the end of metal-between a pair of adjacent and o'peratively associated rolls; providing a dam at each end of the rolls to maintain the molten metal in said bath; rotating said rolls to cause the ejection of solidified metal from the bight of the rolls; and controlling the thermal conditions so that the temperature of the solidified metal at the bight oi the rolls is substantially the same in the zones adjacent to the dams and the intermediate zones of the molten bath; the said controlling operation involving the regulation of the heat supplied to the ends 0! the rolls and associated dams whereby compensation is effected for excess cooling of the ends 0! the rolls and/or dams, and whereby the solidification of excessive solid metal at the ends of the rolls is avoided.

5. The method 0! producing solid metal of substantially constant cross section throughout its length directly from a mass of molten metal which comprises establishing a bath of molten metal between a pair of adjacent and operatively associated rolls; providing a dam at each end of the'rolls to maintain the molten metal in said bath; maintaining said molten metal to a selected height in said bath; rotating said-rolls to cause the ejection of solidified metal from the bight oi the rolls; and providing the ends of the dams with a lower heat conductivity than the central zones of the rolls to control the thermal conditions so that the temperature of the solidified metal at the bight oi the rolls is substantially the same in the zones adjacent to the dams and the intermediate zones oi' the molten bath.

} 6. The method of producing solid metal of substantially constant cross section throughout its length directly from a mass of molten metal which comprises establishing a bath of molten metal between a pair of adjacent and operatively associated rolls; providing a dam at each end 0! the rolls to maintain the molten metal in said bath; maintaining said molten metal to a selected height in said bath; rotating said rolls to cause the ejection of solidified metal from the bight oi the rolls; and providing dams with lower heat conductivity than the rolls to control the thermal conditions so that the temperature oi the solidified metal at the bight of the rolls is substantially the same in the zones adjacent to the dams and the intermediate zones of the molten bath.

7. The method of producing solid metal of substantially constant cross section throughout its length directly from a mass of molten metal which comprises establishing a bath of molten metal between a pair of adjacent and operatively associated rolls; providing a dam at each end 01' the rolls to maintain the molten metal in said bath; maintaining said molten metal to a selected height in said bath; rotating said rolls to cause the ejection of solidified metal from the bight o! the rolls; and expanding the cross section of the metal solidified at the ends of the rolls gradually stantially constant cross section throughout its length directly from a mass of molten metal which comprises establishing a bath of molten metal between a pair of adjacent and operatively associated rolls; providing a dam at each end 0! the rolls to maintain the molten metal in said bath; maintaining said molten metal to a selected height in said bath; rotating said rolls to cause the ejection of solidified metal from the bight of the rolls and spraying less water at the ends of the rolls than at the intermediate zones of the rolls to control the thermal conditions so that the temperature of the solidified metal at the bight oi the rolls is substantially the same in the zones adjacent to-the dams and the intermediate zones of the molten bath.

9. The method of producing solid metal of substantially constant cross section throughout its length directly from a mass of molten metal which comprises establishing a bath oi molten metal between, a pair of adjacent and operatively associated rolls; providing a dam at each end oi the rolls to maintain the molten metal in said bath; maintaining said molten metal to a selected height in said bath; rotating said rolls to cause the ejection of solidified metal from the bight of the rolls; and applying a heat insulating material to the dams to control the thermal conditions so that the temperature of the solidified metal at the bight of the rolls is substantially the same in the zones adjacent to the dams and the intermediate zones of the molten bath.

10. The method of producing solid metal of substantially constant cross section throughout its length directly from a mass of molten metal which comprises establishing a bath of molten metal between a pair of adjacent and operatively associated rolls; rotating said rolls to cause the ejection of solidified metal from the bight of the rolls; maintaining said molten metal to a selected height in said bath; and regulating the power input applied to the rolls to not less than one horse power per foot of width of metal per foot per minute of peripheral speed of advance of the solidified metal to and through the bight of the rolls.

11. The method of producing solid metal of g substantially constant cross section throughout its length directly from a mass of molten metal which comprises establishing a bath of molten metal between a pair of adjacent and operatively associated rolls; rotating said rolls to cause the ejection of solidified metal from the bight of the rolls; maintaining said molten metal to a selected height in said bath; and regulating the temperature in the molten bath in accordance with changes shown by a meter associated with the driving means for; said rolls whereby the said temperature is increased with increases of said meter and is decreased with decreases of said meter.

12. The method of producing solid metal of substantially constant cross section throughout its length directly from a mass of molten metal which comprises establishing a bath of molten metal between a pair of adjacent and operatively associated rolls; rotating said rolls to cause the ejection of solidified metal from the bight of the rolls; maintaining said molten metal to a selected height in said bath; and adding molten metal'to said molten bath in amounts depending upon indications of a meter associated with the driving means for said rolls whereby the said amounts are increased with decreases in the indications of said meter and are decreased with increases in the indications of said meter.

13. The method of producing solid metal of substantially constant cross section throughout its length directly from a mass of molten metal which comprises establishing a bath of molten metal between a pair of adjacent and operatively associated rolls; rotating said rolls to cause the ejection of solidified metal from'the bight of the rolls; maintaining said molten metal to a selected height in said bath; adding molten metal to said bath; and varying said additions of molten metal with changes indicated by a torque indicator operatively associated with the said rolls whereby the additions are increased with'decreases in the said indications of said indicator and are decreased with increases in the indications of said meter.

14. The method of producing solid metal of substantially constant cross section throughout its length directly from a mass of molten metal which comprises establishing a bath of molten metal between a pair of adjacent and operatively associated rolls; providing a moving dam at each end of the rolls to maintain a bath of molten metal; maintaining said molten metal to a selected height in said bath; rotating said rolls to cause the ejection of solidified metal from the bight of the rolls; and regulating the depth of the bath'to a height more than the distance that the molten metal falls freely plus any static head of molten metal being fed to the bath whereby detrimental eddies of incoming molten metal are not created and solidified metal adjacent to the surface of the rolls and to the big'ht thereof is not detrimentally afl'ected.

15. The method of producing solid metal of substantially constant cross section throughout itslength directly i'rom'a mass of molten metal which comprises establishing a bath of molten metal between a pair of adjacent and operatively associated rolls; providing a moving dam at each metal to a selected height in said bath; rotating said rolls to cause the ejection of solidified metal from the bight of the rolls; introducing a stream of molten metal into sald bath; and dividing the said stream at a region closer to the surface of the bath than the depththereof whereby detrimental eddies of incoming molten metal are not created and solidified metal adjacent to the surface of the rolls and to the bight thereof is not detrimentally affected.

16. The method of producing solid metal 01 substantially constant cross section throughout its length directly from a mass of molten metal which comprises supplying molten metal between a pair of adjacent and operatively associated shell-like cylindrical rolling surfaces; applying rolling pressure internally to at least one of said cylindrical rolling surfaces in such a direction as to have such pressure act substantially in the line passing through the centers and the line of tangency of said surfaces thereby providing the effect of continuous and solid rolls of great rigidity and strength in said line adapted to consolidate the partly plastic metal solidifying and crystallizing therebetween without any irregularities of the surface; causing by said internal rolling pressure rotation of said surfaces at a coordinated speed to move the thus-consolidated solidifying and crystallizing metal between said rolling surfaces and to eject solidified metal from the bight of said rolling surfaces free from irregularities of cross section and having a smooth and uniform surface; and controlling the thermal conditions so that the temperature of the solidified metal at the bight of the rolling surfaces is substantially the same in the end zones and in the intermediate zones.

17. The method of producing solid metal of substantially constant cross section throughout its length directly from a massof molten metal which comprises supplying molten metal between a pair of adjacent and operatively associated shell-like cylindrical rolling members; rotationally supporting said cylindrical rolling members in predetermined operating-position; exerting internal rotary pressure against the surface of a cylindrical cavity within at least one of said rolling members in such a direction as to havesuch pressure act substantially in the line passing through the centers and the line of tangency of said members thereby providing the efiect of continuous and solid rolls of great rigidity and strength in said line adapted to consolidate the partly plastic metal solidifying and crystallizing therebetween without any irregularities of the rotation of said members at a coordinated speed to move the thus-consolidated solidifying and crystallizing metal between said rolling members and to eject solidified metal from the bight of said rolling members free from irregularities of cross section and having a smooth and uniform surface; and internally and externally cooling said rolling members to control the thermal conditions so that the temperature of the solidified metal at the bight of the rolling surfaces is substantiallythe same in the end zones and in the intermediate zones of the molten bath.

18. A casting mill for producing solid metal of substantially constant cross section throughout its length directly from a mass of molten metal comprising in combination a pair of adjacent and operatively associated rolling members adapted to receive molten metal, at least one of said rolling members having a cylindrical cavity therein, means rotatably engaging the inner surface of at least one of said rolling members, said engaging means being constructed and arranged to exert pressure acting substantially in the line passing through the centers and the line of tangency of said members thereby providing the effect of continuous "and solid rolls of great rigidity and strength in said line adapted to consolidate the partly plastic metal solidifying and crystallizing therebetween without any irregularities of the surface, driving means for said engaging means for causing rotation of said members at a coordinated speed to move the thus-consolidated solidifying and crystallizing metal between said rolling members and to eject solidified metal from the bight of said rolling members free from irregularities of cross section and having a smooth and uniform surface, and means for controlling the thermal conditions by regulating the amount of heat supplied to the various zones of the bath so that the temperature of the solidified metal at the bight of the rolling members is substantially the same in the end zones and in the intermediate zones.

19. A casting mill for producing solid metal of substantially constant cross section throughout its length directly from a mass of molten metal comprising in combination a pair of adjacent and operatively associated cylindrical rolling members adapted to receive a bath of molten metal, at least one of said rolling members having a concentrical cavity extending throughout the length thereof, means for maintaining said molten metal to a selected height-in said bath, means including an eccentrically mounted rotatable core member adapted to engage the inrier surface of at least one of said rolling members,

said core member being constructed and arranged to exert pressure acting substantially in the line passing through the centers and the line of tangency of said rolling members thereby providing the effect of continuous and solid rolls of great rigidity and strength in said line adapted to consolidate the partly plastic metal solidifying and crystallizing therebetween without any irregularities of the surface, driving means for said core members for causing rotation of said rolling members ata coordinated speed tomove the thusconsolidated solidifying and crystallizing metal between said rolling members and to eject solidifled metal from the bight of said rolling members free from irregularities of cross section and havinga smooth and uniform surface, and means for controlling the thermal conditions by regulating the amount of heat supplied to the various zones of the bath so that the temperature of the solidified metal at the bight of the rolling members is substantially the same in the end zones and in the intermediate zones.

' 20. A casting mill for producing solid metal of substantially constant cross section throughout its length directly from a mass ofmolten metal comprising in combination a pair of adJacent and opetatively associated cylindrical rolling members adapted to receive molten metal, at least one of said rolling members including an inner core within an outer shell of an internal diameter considerably in excess of the outside diameter of the core, means for rotatably supporting said outer shell and said inner core in mutually engaging eccentric position,.said core being constructed and arranged to'exert pressure acting substantially in the line passing through the centers and the line of tangency of said rolling members thereby providing the effect of continuous and solid rolls of great rigidity and strengthin said line adapted to consolidate the partly plastic metal solidifying and crystallizing therebetween without any irregularities of the surface, means for driving said core for causing rotation of said rolling members at a coordinated speed to move the thus-consolidated solidifying and crystallizing metal between said rolling members and to eject solidified metal from the bight ofjsaid rolling members free from'irregularities' of cross section and having a smooth and uniform surface, and means for internally and externally cooling said rolling members to control the thermal conditions so that the temperature of the solidified metal at the bight of the rolling members is substantially the same in the end zones and in the intermediate zones.

CLARENCE W. HAZEIE'I'l.

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