US2063677A - Method of rolling copper strips and the like - Google Patents

Description

Dec. 8, 1936.

J. M. HUGHES. ET Al.

METHOD OF ROLLING COPPER STRPS AND THE LIKE 2 Sheets-Sheet 1 Filed' April ll, 1932 A@ m El.; n E, m wm mm NN NN QN NQ SQ Q S f k QW M QQ n QQ S5 N I4 HH Jo/zMHzzg/zes Jbsep/z ECU/'fer E/MfaCEieag/e @M 2%@ atroz/MW Dec. 8, 1936.

J. M. HUGHES ET Al.

METHOD OF ROLLING COPPER STRIPS AND THE LIKE Filed April l'l, 1932 2 Sheets-Sheet 2 @MGM l Patented Dec. 8, 1936 UNITED sTATEs PATENT ...-:oEFicE John M. Hughes and Joseph H. Carter, Youngstown, Ohio, and Eustace E. Reagle, Sharon, Pa., assig'nors to Sharon Steel Corporation, a corporation oi' Pennsylvania Application April 11, 1932, Serial No. 604,510

5 Claims. (Cl. 80-60) The invention relates to the art of rolling cop per or brass or similar non-ferrous metal strips and the like from large ingots, and more particularly to the rollingof copper and the like to produce coiled strips and the like having characteristics superior to the characteristics of such strips produced in accordance with standard practice.

Cold rolled copper strips have been made from cake copper cast in various sizes, say from 8" x 24 x 1.25 to 14" x 28" x 2" weighing from to 260 pounds. The copper cakes are scalped and sometimes pickled and are then passed through cold rolls to about i'lfty percent reduction after which they are annealed and'pickled. Cold rolling followed byannealing and pickling after each fifty percent reduction is continued until the required iinished gauge is obtained.

Cold rolled copper strips have been made from cake copper cast in larger sizes having thicknesses of from three to four inches and weighing about 500 pounds. These larger cakes are scalped and sometimes pickled, and are then hot rolled on 4ordinary mills to say 0.125 to 0.187" in thickness, and are then coiled, the coils weighing approximately 500 pounds. The coiled strips are then cold rolled to say 0.005" with one or more anneals and pickles.

The hot rolling has been performed in accordance with prevailing practice on an ordinary hot mill of either the pullover type or the reversing type, and the hot rolled product is usually somewhat brittle andhas cracked edges, which require slitting or trimming before using.

In accordance with standard practice, cold rolling is performed on standard two high mills with hand or power screw downs, the use of which re' quires annealing and pickling operations after each fifty percent reduction; or cold rolling may be carried out on a "Steckel mill enabling` greater reductions and fewer anneals and pickles.

However, when long length strips are made by hot and cold rolling and annealing in accordance' with standard practice, the cold rolled strips are not only very brittle and will not stand sharp bending without cracking,'but also have such cracked edges as to require their edges to be trimmed before tubes or other products can Abe made from the same.

Moreover,y strips made even from v500 pound cakes do not have suiiicient length to be economically cold rolled on a Steckel mill", so that two ormore of the same are 'frequently joined together end to end for being cold rolled on a "Steckel mill. 4

It is therefore a principal object of the present invention to roll copper strips and the like with increased production, and with a reduction in manufacturing costs, and to obtain a product having improved qualities and characteristics.

It is also an object of the present invention to 5 hot roll copper strips and the like in extremely long lengths to form coils weighing G-pounds y and upwards, which may be economically cold rolled on a Steckel mill" without splicing.

It is likewise an object of the present invention to roll copper strips and the like by hot and cold rolling so that a nished product may beiobtained without, in most instances, requiring any annealing operations to be performed.

It is a further object of the present invention to roll copper strips and the like, so that the resulting hot or cold rolled product has edges which are than has been obtained by previous practice.

Furthermore it is an object of the present invention to roll copper strips and the like directly from large cast ingots Weighing, say, 8000 pounds in much less time and with much less labor than are required by standard practice.

Likewise it is an object of the present invention to eliminate the continual manual handling and rehandling of copper coils andthe like, which ac- 5 companies the present practice of hot and/or cold rolling of copper strips and the like.

And finally, it is an object of the present invention to roll copper strips and the like and avoid the present hot and cold rolling diiculties; and 40 to obtain a product in which undesirable characteristics are eliminated.

We have discovered that the above and other objects can be accomplished by our improvements in the art of rolling copper strips and the like wherein cast copper ingots and the like, which may be 20 x 20 x 5-6", weighing about 8000 pounds, are heated to between 1500 F. and 1700 F., say 1550 F., are then hot rolled by a plurality of passes preferably on a two-high reversing blooming mill, in some 2 to 3 minutes, and are then end cropped and sheared to form blooms. The blooms are then continuously rolled on a plurality of reducing and edging mills, and are heared to form slabs and the like of any de- 55 sired dimensions and weight, which may be say 2 inches thick by 6 inches wide by 30 feet long weighing approximately 1250 pounds. l

The slabs are then reheated to between 1400 F. and 1700 F., say about 1500 F., are then reduced in a continuous hot mill, including some edge rolling, to a bar or strip or sheet of any desired dimensions, which may have a thickness of say 0.1 inches more or less, all in approximately one minute or less or before the strips have cooled below a proper hot rolling temperature, and the strips are then coiled. The finishing temperature of the strips is between 800 F. and 1300" F., say about 1100 F., and the coiled strips weigh approximately 1250 pounds, according to the size of the slabs from which they are rolled.

The equipment for continuously hot rolling the slabs to form strips and the like may include a series of some eleven stands of hot rolls, and some four sets of vertical axis edge rolls may be located, one before the rst stand of hot rolls, one after the second stand of hot rolls,l one after the fourth stand of hot rolls and one after the fth stand of hot rolls. The'rolls are pref-. erably operated at a speed which will pass any given portion of the strip through the series'of rolls in approximately thirty seconds, so that the entire strip will pass through the continuous hot rolling mill in approximately one minute or less v in order that the hot roll reduction may be performed before the strip has cooled below a proper hot rolling temperature. `1

We have discovered that hot rolled strips made in accordance with the present invention have true or solid edges and that they are considerably more ductile than hot rolled strips made by prevailingv practice.

It is known that copper has higher ductility at high temperatures in an oxidizing atmosphere,V

and this characteristic may possibly account for the improved characteristics of the hot rolled product made in accordance .with the present invention, because so much work is performed upon the metal when the same has high ductility at high temperatures in an oxidizing atmosphere in a short space of time, i. e.,` reduction from a andslabs handled is much less than a similar ratio which might be established with respect to cakes rolled in accordance with prevailing practice.

The hot rolled coiled strips may then be cold rolled to a thickness of 0.005 inch or lighter without any annealing, and a much greater yield is obtained than has been obtained by previous practice. Moreover the edges of the cold rolled product are so true or solid as to require little, if any, trimming, and the cold rolled product is so ductile thatit may be bent with' a flat fold -with or parallel to the grain without cracking the folded edge.

Av combination and general arrangement of commercial apparatus, which has been successfully utilized in carrying out the new art of rolling copper strips and the like, is diagrammatically illustrated in the accompanying drawings, forming part hereof, in which:-

Figure 1 is a plan view of a soaking pit. a blooming mill, a shear, and a crop pit, together with intervening conveyors, for reducing ingots to blooms by hot rolling operations.

Fig. 2 is a side elevation of the same; Fig. 3 is a plan continuation view of the hot rollingapp'aratus, including a tandem series of five hot roll stands with edge roll stands located before the rst and third hot roll stands, for rolling the blooms to slabs; a shear for cropping od ends or cutting the slabs to desired lengths;

a plurality of hotv beds; a stand of pinch rolls;

and a delivery table; together with intervening conveyors;

Fig. (l is a side elevation of the same;

Fig. 5 is plan continuation view of the hot rolling apparatus, including a charging conveyor, a slab heating furnace, a pusher, a shear, a tandem series of some eleven continuous roughing and finishing hot roll stands with some four edging roll stands, and a delivery conveyor;

Fig. 6 is a side elevation of the same;

Fig. 7 is a plan continuation view of a conveyor, vibrators, apron conveyors, pinch rolls, shears, reels, conveyors, and delivery stations; and

Fig. 8 is a side elevation of the same.

Similar numerals refer to similar parts throughout the drawings.

For carrying out the improved art of ,rolling copper strips and the like, a cast copper ingot, which may be x 20" x 5-6, weighing about 8000 pounds, may be delivered to the'soaking pit i0 wherein it is heated to between 1500 F. and 1700 F., say 1550 F., and is withdrawn therefrom and passed by a conveyor iito a twohigh reversing blooming mill i2 wherein it yis given a plurality of passes to break the ingot down to bloom size.

The bloom is carried from the blooming mill i2 by a conveyor i3 to a shear i4 for cropping irregular ends of the-bloom and for cutting the same into convenient or desired bloom lengths, the end crops being received by the crop pit i5.

A conveyor i8 receives the blooms for delivering them to the continuous hot rolling mill i9, which may preferably include tandem series stands of some ve hot rolls i 9a, i911, ISC, I 9d and ie, and edge rolls i90.' and |9c located ahead of the first and third stands ofhot rolls Ha and 00e wherein the blooms are rolled by continuous single ply passes vto slab size. The slabs are then delivered to the shear 20 and cut to convenient slab lengths, say two inches thick byl six inches wide by thirty feet long, each weighing approximately 1250 pounds, or the same are rolled and cut to other desired sizes according to the desired dimensions of the final product to be produced. The slabs are then delivered by a conveyor 2i to hot beds 22, whence pinch rolls 23 may deliver the same-to the delivery table 2l.

The slabs are then transferred from the table 2d to a charging conveyor 25 and charged into a heating furnace 26 wherein they are reheated to between 14.00 F. and 1700 F., say about 1500 F.. and are delivered from the heating furnace 26 by vpusher 2l to continuous roughing and nishing mills indicated generally at 28 and 29 respectively.

The roughing `mill may include a shear 28a.

some ve continuouskhot roll stands 28h, 28o, 28d, i

28e and 28,1, with edging mill stands 28h', 28d', 28j' and 28g' located before the flrst, third and reduced by single ply passes in the immediately.

succeeding operationsv of the successive stands of the mills 2B and 29 vt'o a strip having a thickness of say 0.1 inch more or less, all in approxi.

mately one minute or less, and before the strip has cooled below a proper rolling temperature of between 800 F. and 1300. F., say about 1100 F.

The hot rolled strip is then passed to one of the vibrators 30, along an apron conveyor 3L.

through pinch rolls 32 to a reel 33 for the purpose of beingcoiled,l the shear 34 being utilized for cutting off irregular ends of the strip, after which the coils are passed along conveyors 35 to a delivery station V36.

The hot rolled strip coils may then be passed through cold rolls and rolled to approximately 95 percent reduction, say. from 0.1" to 0.005" without any annealing, and then coiled.

The hot rolled strips thus made have true or solid edges and are considerably more ductile than hot rolled strips made by prevailing practice; and a much greater yield is obtained than vhas been obtained by previous practice. Moreover, the edges of the cold rolled strips are so true or` solid as to require little, if any trimming, and the strip is so ductile, without annealing, that it may be bent with a flat fold without cracking the folded edge. In other words, the hardness of the finished materials is not increased so much and ductility is not decreased so much by ,carrying out the present process as occurs in `carrying out prevailing practice.

The term 1copper strips utilized in the appended claims is intended to'reier to copper, or

brass, or similar non-ferrous metals; and to strips,A

or to sheets and the like, which may be sheared from the strips.

It is not intended to limit the scope of the present invention to .the particular temperatures mentioned, because various brasses or similar non-ferrous copper alloys require diiferent hot rolling temperatures lower or higher than the particular temperatures referred to. Y

Nor is it intended to limit the scope of the presentinvention to the particular rolling times referred to,- `because certain alloys' may require slower rolling; although one of the essential features of the present invention involves the rapid hot rolling of copper or brass or similar nonferrous metals to extreme reductions of say approximately 95'percent by continuous successivey deep drafts. And iinal1y,it is not intended to limit the scope of the present invention tothe particular ingot sizes. or to the particular thicknesses of hot rolled or cold rolled strips referred to, be-

cause these sizes and thicknesses may be varied in accordance with the nature of the product to be produced.

We claim:-

1. The method of rolling a-copper strip which includes heating a slab to rolling temperature, continuously reducing and edge rolling the same to form a hotA rolled strip before the strip has cooled below a proper hot rolling temperature, yand then cold rolling the hot oiled strip to approximately 95A percent reduction to form a ductile cold rolled strip without annealing the same.

2. The method of rolling a copper strip which includes heating a 2" thick slab to rolling temperature, continuously reducing and edge rolling the same to form a 0.1" thick hot rolled strip before the strip has .cooled below a proper hot rolling temperature, and then cold rolling the hot rolledstrip to a thickness of approximately 0.005 to form a ductile cold rolled strip without annealing the same. v

3. The method of rolling a copper strip which includes heating a slab to rolling temperature,

continuously reducing and edge rolling the same to form a hot rolled strip before the striphas cooled below a proper hot rolling temperature.

and coiling the same, cold rolling the hot rolled strip to approximately 95 percent reduction to form a ductile cold rolled strip without annesaling the same, and then coiling the same.

4. The method of rolling copper strips which includes heating an ingot to rolling temperature,

breaking down the ingot by Arolling to form blooms, continuously rolling` the blooms to form slabs, heating the slabs to rollingltemperature,

lcontinuously reducing and edge rolling the slabs to form strips each weighing 1000 pounds and upwards by single ply passes before the strips have cooled below a proper hot rolling tempera` ture, coiling the hot rolled strips, and then cold rolling the hot rolled strips to form ductile cold rolled strips without annealing the same.

5. The method of rolling copper strips which includes heating an ingot to rolling temperature, breaking down the ingot by .rolling to form blooms, continuously rolling the blooms to form slabs, heating the slabs to rolling temperature, continuously reducing and edge rolling the slabs r to form strips by single ply passes before the strips have cooled below a lproper hot rolling

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