US2183010A - Direct rolling of hot metal - Google Patents

Description

Dec. 12, 1939. c. D. coxE DIRECT ROLLING OF HOT METAL Filed Nov. 28, 1936 4 Sheets-Sheet 1 INVENTOR. C/MRL E! D. COXE C. D. COXE Dec. 12, 1939.

OF HOT METAL DIRECT ROLLING Filed Nov. 28, 1936 4 Sheets-Sheet 2 I INVENTOR. CHARLES D. (OX5 BY 7 i! ATTORNEY l I I I I I I I I I I I I I I I I I I I l I I I I I I I I I I I l l I I I 1 I I I {I Dec. 12, 1939 c. D. COXE DIRECT ROLLING OF HOT METAL 4 Sheets-Sheet 3 Filec} Nov. 28, 1936 INVENTOR. (M4 RLES D COXE ATTORNEY Dec. 12, 1939.

C. D. COXE DIRECT ROLLING 0F HOT METAL Filed Nov. 28, 1936 4 Sheets-Sheet 4 INVENTOR.

(EM/HE'S .0. cont? BY E ATTORNE Patented Dec. 12, 1939 UNITED STATES PATENT OFFICE 2,183,010 DIRECT ROLLINGOF HOT METAL Charles D. Coxe, Youngstown, Ohio Application November 28, 1936, Serial No. 113,222

Claims.

The present invention relates to the art of manufacturing metal plates or sheets and more particularly to method and apparatus for. producing such plates or sheets directly from metal in the hot fluid state. The invention constitutes an improvement on the direct rolling method first advanced by Henry Bessemer and disclosed in Bessemers U. S. Patent No. 49,053.

Various attempts have heretofore been made to apply the fundamental concepts taught by Bessemer to a commercially feasible and economical production system, but none have been particularly successful, especially in the production of steel sheets or strip, because of various difiiculties encountered. A principal objection to the devices heretofore used is the difficulty of properly defining the edges of the formed metal. As is well known in the art, a delicate relationship must be maintained between the initial temperature and composition of the fiuid metal and the temperature and speed of rotation of the extruding rolls. With devices of the prior art, these relationships are diificult to maintain. Also the forming of a satisfactory joint between the pouring means and the extruding means and thus the maintenance of a proper static pressure of the fluid metal has presented a serious problem.

The primary object of my invention is to provide means whereby the sheet or strip issuing from the extruding rolls will have sharply defined edges and will be of uniform and controllable width.

Another object of my invention is to provide novel and easily replaceable means for conveying fluid metal into the extruding area proper to eliminate any danger of injury to the apparatus and to reduce periods of, .inoperatability' thereof.

These and other objects and advantages of the invention will become obvious from a consideration of the drawings and the following specification.

In the drawings:

Figure l is a vertical cross-sectional View of an apparatus constructed inaccordance with my invention,

Figure 2 is a plan View of the apparatus taken along the line 2-2 of Figure 1, Y

Figure 3 is a vertical cross-section through the extruding rolls,

Figure 4 is a planview of a modified form of the apparatus, certain elements. being shown phantomally, 1,

Figure 5 is a vertical section of the apparatus of Figure 4,

Figures ,6 and 7 are plan andsection views, re-

' spectively, of a modified form of liquid metal side of the apparatus and another heavier pedes- ;10

tal H positioned centrally on the opposite side of the apparatus. These pedestals may be secured to the concrete foundation bed I2 in any suitable manner. cradled between the pair of pedestals I0 and the pedestal it are the upper and lower 15 bearing supporting rings I3 and M respectively, which support the chocks l5 carrying the bearings l6 and I1 for the rotatable support of the four vertically extending extruding rolls l0. I9, 20' and 2|. The lower bearings I1, in addition 20 to preventing separation of the rolls of the mill, perform the added function of a thrust bearing to carry the weight of the rolls. The intervals between the rolls are adjustabl by operation of the setting screws 22 and 23 25 which are in screw-threaded engagement with the frames l3 and I4 and have their ends in abutting engagement with the chocksv l5. Any suitable means may be employed to rotate and indicate the position of the screws 22 and 23.

As shown more particularly in Figure 3, the rolls may be hollow and have integral therewith hollow shafts which are journaled in the bearings above mentioned. Universal joints or wobblers 24 connect the lower ends of the shafts with the 35 spindles 25 which are, in turn, connected with the meshed driving gears 21 through the wobblers 28. Gears 21 are housed within a suitable closed case26 and are driven by a motor 3| through pinion 30, gear 29 and pinion 32. The direction 40 of rotation of the rolls is indicated in Figure 2.

To provide means for passing cooling fluid through the rolls, the lower hollow shafts are provided with a plurality of circumferentially spaced apertures 34, (see Fig. 3) about which are placed the slip rings 35 adapted to convey cooling fluid from the tubes 36 to the apertures 34.

employed to heat the rolls to bring them up to their proper initial temperatures.

I obviate many of the difiiculties of the devices of the prior art by introducing the molten metal at the bottom of the apparatus, that is, by bottom pouring, as it is termed in the art. To this end I provide a novel metal supplying device generally indicated at 42, which consists essentially of a generally U-shaped tube which may be a fired clay product having an enlarged opening 43 constituting a pouring fountain and reservoir for the molten metal. The horizontal portion 44 of the tube has the lower surface of its opening inclined upwardly from the, bottom of the pouring end of the tube. A slag trap 48 is provided in the roof of the horizontal duct which is operatable to skim off and trap slag which may be poured into the reservoir 43 along with the molten metal. A plug 49 is inserted in the side wall of the tube at its lowest point in order that all the contents of the tube may be drained when desired. The right leg of the U-shaped pouring and feeding assembly is enlarged as shown at 45 to provide a stool having a fiat upper surface to fit closely against the lower end surfaces of the extruding rolls. A vertical duct 46 extends centrally through the stool and is operative to feed molten metal to the space between the rolls. A dead end duct 41 is provided in thestool to form a space for the lodgment of solid particles which may be washed in with the flow of molten metal. If desired, the end of the duct 41 may have an opening to the atmosphere to provide an escape for entrapped air. The passages through the member 42 may be lined with suitable refractory tile 53. The pouring and feedin member 42 is supported on' the standard 50 which may readily be raised and lowered by hydraulic cylinder 5| operated by fiuid passing through a) tube 52. It should be noted that the stool 45 is positioned between pairs of roll supporting and rotating shafts and couplings and that a portion of it extends above the lower bearings l1 and the lower frame member l4. The hydraulic cylinder therefor performs two functions. 1. e. it is operative to maintain the stool in constant engagement with the lower surfaces of the rolls and it is operative to lower the pouring and feeding assembly whereby it may readily be removed from the mill for replacement or repair.

The operation of the apparatus thus far described should be apparent. The rolls are driven in unison in the direction indicated by the intermeshing gear wheels 21 and molten metal flowing into the space between the rolls'reaches its point of incipient fusion near the common plane of the .axes of rolls l8 and I9 and also near the common plane of the axes of the rolls 20 and 2|. The metal is then extruded by operation of the rolls in two strips moving in opposite directions as shown. If desired, suitable means may be employed to apply tension to-the issuing strips to prevent sticking between the strips and rolls.

To this end I provide tensioning ,rolls 85 which are adapted to tightly engage the issuing strip and by having their peripheral speeds greater than the linear speed of the issuing strip apply "tension to the strip.

In carrying out the method of direct rolling of.

metals, extreme accuracy must be maintained in the temperature and static pressure of the molten metal and in the temperature and speed of rotation of the rolls. The use of the bottom pouring device and the reservoir 43 enables me to maintain the temperature of the metal c nstan Ill it is a simple matter to add either hotter or cooler metal to the reservoir. Also by maintaining a constant level of liquid in the reservoir a constant static pressure is maintained on the metal entering the extruding space between the rolls. The cooling effect of the rolls may be varied by varying the supply of cooling fluid passing through the header 3'! and the speed of rotation of the rolls may be controlled by controlling the speed of the variable speed motor 3|. If desired, thermocouples or other temperature sensing devices may be positioned adjacent the rolis and molten metal passes to aid in keeping the proper temperature balance required.

Because of the tendency of the molten metal in the pouring tube and in the space between the rolls to seek its own level, the height of the metal in the space between the rolls may be readily controlled by varying the height of the metal in the pouring fountain and reservoir 43. The width of the extruded strips is dependent, of course, on the height of the metal in the space between the rolls. It is therefore apparent that I have provided means to easily vary and control the width of the extruded strips. It is only necessary to vary 'and control the height of the molten metal in the pouring fountain and reservoir to vary and control the width of the extruded strips.

Figures 4 and 5 illustrate a modified form of apparatus wherein a sheet metal container 55 is closely fitted within the space between the rolls. The container 55 is open at both ends and its side walls are bent to conform closely to the curvature of the rolls with which they are in sliding contact. The contact between the walls and the rolls insures a sufficient rate of heat conductivity to result in at least the essential partial solidification of the molten metal at the point of extrusion and prevents burning of the metal of the walls. The container is supported on the upper flat surface of the stool 45, the orifice in which supplies the molten metal. A pair of slits 56 are provided in opposite sides of the container, arranged parallel with each other and with the axes of rotation of the rolls. These slits are positioned adjacent to but on the inner side of point of extrusion of the metal.

To provide lubrication between the rolls and the curved surfaces of the container, I provide a graphite brush 5'! extending the length of each roll, the purpose of which is to deposit a small amount of graphite lubricant on the surface of the roll before it comes in contact with the surface of the container. Brushes 51 are seated within housings 58 which enclose the springs 59, the springs 59 maintaining the brushes in contact with the surface of the rolls. I

The how of metal along the side walls of container 55 results in partial solidification thereof, or at least in sufficient cooling that when it comes in contact with the roll proper at the point of extrusion that solidification takes place there. The structure of Figures v4 and 5 provides an effective seal between the molten metal and the rolls except at the slits which are located adjacent the point of extrusion of the metal.

surfaces of the extruding rolls. This isadvantageominthatitprovidesabetterwearings face between the stools and the rolls and a more effective seal for the molten metal. The stool is provided with an extended portion 62 of a shape to fit closely within the lower portion of the space betwen the rolls. This provides a further seal for the molten metal.

Figures 8 and 9 illustrate a simpler form of apparatus wherein but two rolls 10' are used.

These rolls are mounted parallel with each other in an inclined plane and are rotatably supported in bearings 12 carried by the cross members 13 bridging the two supporting frames 14. A refractory lined hopper 15 is fitted about the set of rolls to form a reservoir for molten metal coming into the mill from the pouring spout 11. As shown, the lower surface 16 of the hopper is in the plane of the lower ends of the roll. to prevent loss of metal. The hopper may be supported in anysuitable manner as by the standard 80. The rolls are heated and cooled as in the other embodiments disclosed, and are driven by spindles 25 through wobblers 24 and gear train 18 by the variable speed motor l9. When the hopper is fllled'with molten metal at the proper temperature and the rolls are at the proper temperature and rotated at the proper speed, a strip of formed metal will issue from the apparatus as suggested by Figure 9 of the drawings.

Having thus described my invention what I claim is:

1. Apparatus for thecontinuous production of metal shapes comprising a set of four parallel vertically extending extruding rolls arranged in pairs, the rolls of each pair being in contact with each other but spaced from the rolls of the other pair, means to rotate said rolls, the rolls of a pair rotating in opposite directions in relation to each other and in relation to the adjacent rolls of the other pair, and means to supply metal in the fluid state to the space between the rolls.

2. Apparatus for the continuous production of metal shapes comprising two pairs of parallel vertically extending extruding rolls, the rolls of each pair being in contact with each other but spaced from the rolls of the other pair, means to rotate said rolls whereby the rolls of a pair rotate in opposite directions in relation to each other and in relation to the adjacent rolls of the other pair, means to supply metal in the fluid state to the space between the rolls comprising a U-shaped conduit having a pouring fountain on one leg and an orifice discharging into said space on the other leg.

3. Apparatus for the continuous production of metal shapes comp ising a set of four parallel vertically extending extruding'rolls arranged in juxtaposed position to define a space between the rolls, a container in said space having its walls bent to conform to the curvature of said rolls, the walls being in sliding contact with the rolls, a pair of slits in opposite sides of said container, said slits being parallel with each other and with the axes of rotation of the rolls and means to rotate said rolls in such manner that liquid metal within said container and issuing from said slits is caused to be extruded.

4. Apparatus for the continuous production of metal shapes comprising a pair of cylindrically shaped extruding rolls positioned on parallel inclined axes, means to rotate said rolls in opposite directions, a hopper located above said rolls, one wallof the hopper having its inner surfacein the plane of the lower ends of the rolls, and means to supply metal inthe fluid state to the hopper.

5. Apparatus for the continuous production of metal shapes comprising a box-like frame, four hollow extruding rolls vertically positioned in said frame and mounted on parallel axes, said rolls being rectangularly arranged to define a space between the rolls, means to rotate said rolls comprising a gear train positioned l. :neath said rolls, a motor for driving said train, spindles having universal joints connecting said train and rolls, means to conduct cooling fluid through said rolls comprising passages through the. roll supporting and rotating shafts, outlets in said passages below and above said rolls, means to conduct cooling fluid into said passages through the lower outlets and out of said passages through the upper outlets, a pouring tube comprising a generally U-shaped structure having a pouring fountain positioned to one side of said frame, a horizontal portion extending beneath said frame and a stool having an upper fiat surface to engage the lower end surfaces of the extruding rolls.

6. A metal supplying means for a direct rolling mill of a type utilizing a plurality of extruding rolls comprising a stool of refractory material having a metallic ring to slideably engage a portion of the end surfaces of the extruding rolls, an extension on said stool closely fitting between said rolls for a. portion of the longitudinal distance, and a passage through said stool and extension.

7. Apparatus for the continuous and direct production of metal shapes comprising four parallel vertically extending extruding rolls rectangularly arranged to define a space between the rolls, a metal supplying means comprising a stool adapted to slideably engage the lower end surfaces of the rolls, an open-ended container supported on said stool and positioned within said space and having side walls bent to conform to the curvature of said rolls a pair of oppositely aligned slits in said container, each positioned adjacent the common plane of two of said rolls, a passage through said stool communicating with said container, means to supply liquid under pressure to said passage and container, and means to rotate said rolls whereby metal issuing from said slits will be extruded by said rolls.

8. In combination with a direct rolling mill having vertically extending extruding rolls, a metal supplying device comprising a generally U-shaped refractory lined tube, one of the legs of the tube extending above the other leg thereof and being provided in its upper portion with an enlarged cylindrically shaped space constituting a reservoir, the other leg of the tube constituting an enlarged stool having a flat upper surface to engage the lower edges of the extruding rolls, said stool including a vertical passage for the flow of metal to the extruding rolls and means to raise and lower said metal supplying device.

9. The method of producing a strip from plastic material which consists of extruding the plastic material between a pair of moving surfaces, the surfaces being composed of upwardly extending parallel linear increments, said increments movable laterally in such manner that continuously changing portions of the two surfaces move toward each other and in the direction of travel of the plastic material being extruded, and controlling the width of said strip by controlling the height of plastic material coming in contact with said surfaces.

10. Apparatus for the continuous production of metal shapes comprising a set of parallel upparallel with the axes of rotation of the rolls, and means to rotate said rolls in such manner that liquid metal within said container and issuing from said slit is caused to be extruded.

C D. COKE.

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