US2162407A - Method and apparatus for manufacturing metallic strip - Google Patents

Description

June 13, 1939. Q H MANlQN` 2,162,407

METHOD AND APPARATUS FOR MANUFACTURING METALLIC STRIP E@ ATTORNEYl- June i3, 1939. c. H. MANION. 291527407 METHOD AND APPARATUS FOR MANUFACTURING METALLIC STRIP Filed Sept. 1l,v 1937 3 Sheets-Sheet '2 AIEEII N om m June 13, 1939. C. H. MANlON 2,162,407

METHOD AND APPARATUS FOR MANUFACTURING METALLIC STRIP Filed Sept. ll, 1937` 3 Sheets-Sheet C5 Qu ATTORNEY@ Patented June 13, 1939 PATENT OFFICE IVIETHOD AND APPARATUS FOR MANU- FACTURING METALLIC STRIP Charles H. Manion, Follansbee, W. Va., assignor to United Engineering and Foundry Company, Y Pittsburgh, Pa., a corporation of Pennsylvania.

Application September 11, 1937, Serial No. 163,359

17 Claims.

` This invention relates to a method and apparatus for reducing hot ingots to cold rolled strip steel, and more particularly to a, mill arrangement or layout for this purpose and to a method of rolling practiced in connection therewith.

The customary practice in producing cold rolled metal strip from hot ingots is to roll the hot ingots into slabs in a blooming or slabbing mill, shear'the slabs, and transfer them to a reheating furnace. Thereafter the slabs are further reduced in a hot roughing mill which may comprise several separate sets of roll stands. Next the ends of the resultant strip are cropped and the strip then hot rolled in a hot strip mill which i5 also comprises several separate sets o roll stands. After the strip leaves the hot mill, it may be pickled and then cold rolled in a cold rolling mill which, like the hot mill, may comprise several separate sets of roll stands. Large tonnage can ,0 be produced with such a method and apparatus, but it Will be appreciated that very great initial and operating costs are involved because so many different types of mills and drives and auxiliaries are required, so much space is required for the 5 equipment, and such a relatively-large number of men are required to control the operations ci the various machines.

Due to these exceedingly high initial and operating costs and the large investment necessi- 0 tated thereby, small companies that do not require a large tonnage ci strip steel are discouraged or prevented fromrolling strip cold, or iin-d it necessary to have other companies do part o the Work, such as produce the slabs or even the hot strip. In some cases it is possible to get along with less equipment by arranging it so that some of it serves a dual purpose, but this saving is largely lost by the increased cost of production resulting from the fact that while part of the 40- equipment is serving its dual purpose other parts must stand idle while waiting for the material being processed. Money invested in expensive mill equipment which is not used at all during a large part of the strip-forming operation adds d greatly to production costs.

It is among the objects of this invention tc provide for reducing ingots to cold rolled strip by apparatus the initial cost of which is materially reduced relative to the cost of apparatus used for this purpose heretofore, by apparatus substantially all of which is maintained in continuous operation while rolling is progressing so as to hold production costs down to a reasonable level, and by apparatus for which a minimum of operators 'f5 and oor space is required, Another object is (C1. Bil- 311) to provide a method of hot and cold rolling by which iulllment of the above-mentioned objects is made possible.

In accordance with this invention hot ingots are reduced to slabs in thesame mill that is later used as a roughing stand for reducing the slabs to rough strips or bars after the former have been sheared and reheated. It is preferred to use a, reversing universal mill for this purpose, and to remove the slabs from its run-out table after they have been sheared so as to deliver them to a slab yard through which they are subsequently charged into a reheating furnace located beside the mills entry table. As fast as bars are rolled in the universal mill they are cropped by the slab shear and conveyed by the run-out table directly to a hot strip mill, preferably of the continuous type, in which they are further reduced to strips which are coiled for storage to be followed at the proper timeby pickling, if desired., The strip mill is adapted to have its rolls for hot strip rolling removed and replaced by rolls suitable for cold rolling (hereinafter referred to as hot and cold rolls, respectively), and similarly its strip guiding equipment is changeable to guiding equipment suitable for cold strip rolling. The same mill is also operatively connected with an uncoiler and one or more strip reels. The uncoller and the strip reels may be arranged in any manner which is suitable to secure cooperation with the strip mill, but I prefer, for the sake of simpiiclty, that arrangement in which they are located below displaceabie sections 'of the conveyor tables at the entry and delivery ends of the strip Tnil.

After all of the slabs that were produced by the universal mill have been rolled into bars and the bars have been roled into hot strip, cold vrolls are substituted for the hot rolls of the strip `mill, the strip guiding equipment between the and the removable table sections are removed to uncover the uncoller and reel. The coils of hot rolled strip, which have cooled with self-annealing if desired, and which may have been pickled in the meantime, are then placed in the uncoller and the strip is cold'rolled in the strip mill and removed as coils from the reel.

While the cold rolling is proceeding in the strip mill, the universal still continues in uninterrupted operation rolling another supply of ingots into additional slabs that are fed into the reheating furnace, and as soon as the cold rolling is iinished and the hot rolling equipment' and table sections are replaced, these slabs, like the:-

stands is changed to that suitable for cold strip, j

the reversible universal mi ll until reduced to a preceding supply, are reduced inthe universal mill to bars which are carried by the run-out table directly to the strip mill where they are hot rolled into strip. Thiscycle of operation is repeated over and over again-as long as ingots are available, and it will therefore be apparent that both `mills as well as the rest of the equipment operate substantially all of the time with no prolonged and costly periods during which part of the apparatus must vnecessarily stand idle. By rolling metal with this apparatus and according to this method, sulcient tonnage of cold` showing the rest of the apparatus; Fig. 3 is an enlarged side view of the uncoiler and associated parts taken on the line III-III of Fig. 2; and Fig. 4 is a side view, similar to Fig. 3, of the cold strip reel taken on the line IV-IV of Fig. 2, Referring to Fig. 1 of the drawings, an ingot buggy I or other suitable device is adapted to deliver hot ingots to one end of a driven entr-y table 2 at the opposite end of which there is a mill 3 in which the ingots are reduced to slabs. As it is an object of this invention to provide as little rolling equipment as possible, a single reversing universal mill is used because its vertical rolls make it unnecessary to provide for ingot-turning apparatus. lAt the delivery side of the mill there is a driven run-out table I on which the slabs are conveyed through a shear 6' by which they are cut into suitable lengths with the help of a shear gauge l.. As the slabs leave the shear they are pushed laterally off the runout table and onto transfer apparaltus 8 by means of a reciprocable slab pusher 9 mounted on the opposite side of the table. 'I'he transfer apparatus is of any suitable form, such as an endless chain conveyor disposed substantially at right angles to the table, and transports the slabs from the table to a piler I I.

`As soon as a sizable pile of slabs has been formed in this manner, the slabs are transferred. to the slab yard where they are inspected. processed and stored; and from storage they are delivered by any suitable means, such as crane hook I2, to an unpiler disposed at one. end of a reheating furnace I3, the opposite end of which is positioned adjacent one side of entry table 2. The unpiler preferably comprises an elevatable support I4 for the pile of slabs, and reciprocable arms I6 for pushing the top slab from the pile into the furnace. Each time the arms are retracted the support is elevated to bring the top slab into the path of the arms. As the slabs are pushed through the reheating furnace in this manner the foremost one is pushed out onto entry table 2 where its lateral movement is arrested by stops I'I mounted on the opposite side of the table. Delivery of ingots from the. soaking pit to mill 3 is then discontinued and the rolling of slabs delivered from the furnace I3 then takes place.

In accordance with this invention, each successive hot slab is rolled back and forth through size suitable for rolling ito strip. Stock that has been thus reduced is referred to herein as bars. 'I'he bars are carried by run-out table 4 'through shear 6, where their ends are cropped, and past slab transfer apparatus 8 to a strip mill I3, of which four stands are shown in Fig. 2 of the drawings. Each bar is reduced in the strip mill, which is preferably a continuous mill, to

hot strip steel that moves over agdelivery table I3 to a hot coiler 2|. Preferably, two vcoilers are provided, each in line with the mill with the usual gate 22 in front of the first one for guiding the hot strip into either one of the coilers. Each coil thus formed is removed from its coiler by any suitable means, such as the coil unloader 23 shown in Patent`No. 2,092,539, and deposited on a conveyor 24 by which it is conveyed to a storage area from which it may later be taken to be pickled. When in storage the coils cool off slowly because of the closely wrapped convolutions of the strip and the result is a self-,annealing of the strip which is often advantageous.

It will thus be seen that with a minimum of 'apparatus ingots are reduced to hot strips which are coiled and stored; the universal mill, shear, andentry and run-out tables being used for the dual purpose of forming slabs from ingots andV bars from the slabs. It follows that a minimum of floor space and a reduced number of operators are required for this apparatus.

In keeping with the foregoing, it is a feature of this invention that the strip mill i8 is convertible into a hot or cold mill whereby substantially one strip mill and its operators are eliminated, and full use is made of strip mill I8 and its operators. That is, strip is cold rolled in this mill after all of the bars have been reduced, whereby shutting down of the strip mill while more slabs are being made is avoided. Accordingly, the strip mill is adapted to receive either hot or-cold rolls, i. e., rolls suitable for hot rolling and rolls designed for cold rolling, to receive strip-guiding equipment for either type of rolling, and the mill drives are suitable for both hot and cold rolling. Roll-changing apparatus 26, preferably of the type shown in Buente Patent No. 2,037,210, is therefore disposed besides each stand of the strip mill in readiness for quickly changing the rolls to form either a hot mill or a cold mill. Furthermore, the run-out delivery tables 4 and I9 .are provided adjacent the strip mill with removable sections, by which is meant sections that can be lifted out of place by a crane or otherwise moved out of the way when desired. As shown in Fig. 3, under the removable run-out table section 27 there is an uncoiler 23, and, as shown in Fig. 4, under the removable delivery table section 3i there is a cold strip reel 32 preferably adapted to exert tension on strip connected to it.

If it is desired to pickle the coiled strip before placing it in the uncoiler uncovered by table section 21, a coil of the hot rolled strip is taken from storage by a crane, which may be the same one that delivers slab piles to the reheating furnace and lifts the removable table sections, and placed on skids 33 down which it rolls to the loading station of picking apparatus 34 which is desirably of the type disclosed in Biggert and Buente patentapplication Serial No. 82,542, filed May 29, 1936. The coil is successively immersed in pickling, washing and rinsing tanks after which it runs endwise down an inclined table 36 from whence it is transported by the crane or other means to uncoiler 28. Strip from this pickled coil is fed through the strip mill in which cold rolls have been substituted for the hot rolls, and is connected to reel 32 from above which table section Si has been removed. As soon as a coil of cold rolled strip is formed on the reel it is removed therefrom for storage, shipment, or further processing.

W'hiie the cold rolling is being carried on, another supply of ingots is fed over entry table 2 to the universal mill by which they are formed into slabs that are removed from the side of the run-out table and piled preparatory to reheating. As soon as all of the pickled coils have been cold rolled the removable table sections are replaced, the cold rolls are removed from the strip mill and the hot rolls replaced therein vby roll-changing apparatus 2b, and the strip-guiding equipment is changed by suitable apparatus, not shown. The strip mill is then ready to perform hot rolling again, so the slabs that were formed during v the period of cold strip rolling are pushed out of the reheating furnace and reduced by the universal mill to bars which are conveyed by the run-out table to the hot mill in order to repeat the cycle o operation just described.

it will be observed that in practicing the method contemplated by this invention hot bars'are produced by the same mill that forms the slabs from which they are made, the'bars are ied di- 'rectly from that mill to a hot strip mill that reduces them to strips that are formed into coils, additional ingots are rolled into slabs Aby the first mill after the hot strip rolling is nished, cold rolls are substituted for the hot rolls of the strip mill, the coils of strip may be pickled and the strip is then rolled in the cold mill just formed while slabs are being produced in the other mill, and the hot strip rolling equipment is operatively reassembled in the strip mill after cold rolling therein is nished in order to reduce to hot strips the bars that are then formed by the rst mill from the slabs previously produced thereby. In short, hot strip rolling is carried on in the strip mill while the universal mill is forming slabs into bars, and the universal mill forms ingots into slabs while cold strip rolling is being carried o n in the strip mill. Consequently, all of the apparatus is kept in operation substantiallil all the time so that there are no prolonged periods during which parts oi it are shut down `which would raise production costs. In addition to requiring a comparatively small investment in apparatus, the layout of the apparatus is compact, especially when the furnace, slab transfer, roll-changer and pickler are all disposed on the same side of the xills as is preferred.;

According to the provisions of the patent statutes, I have explained the principle and mode of operation of my invention, and have illustrated anddescribed what I now consider to represent its best embodiment. However, l desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specically illustrated and described.

I claim:

1. The method of rolling metal comprising rolling ingots or the like in a mill to form slabs, reheating the slabs, rolling the slabs in the same mill to form bars, conveying the bars from said mill directly to a hot strip mill to reduce them to strip, coiling the hot strip, again rolling ingots in. said rst mill to form slabs after said hot strip rolling is iinished, exchanging the strip mill equipment necessary for hot rolling for that needed for cold rolling, cold rolling the hot rolled strip in the cold strip mill thus formed While slabs are being produced by said first mill, returning said hot rolling equipment to the strip mill after said cold rolling is iinished. and repeating this cycle of rolling whereby substantially all of the apparatus is maintained in substantially continuous operation.

2. The method of rolling metal comprising r.,lling ingots in a mill to form slabs, shearing the slabs in a shear, reheating the slabs, rolling the slabs in the same mill to form bars, shearingthe bars in the same shear, conveying the bars from said shear directly to a hot strip mill to reduce them to strip, coiling the hot strip, again rolling ingots in said rst mill to form slabs after said hot strip rolling is finished, exchanging the strip mill equipment necessary for hot rolling for that needed for cold rolling, cold rolling the hot rolled strip in the cold strip mill thus formed while slabs are being produced from ingots by said rst mill, returning said hot rolling equipment to the strip mill after saidcold rolling is finished, and repeating this cycle of rolling whereby substantially all of the apparatus is maintained in substantially continuous operation.

3. Apparatusl for hot and cold rolling metal, comprising a mill for rolling ingots into slabs, means for reheatng said slabs, means for returning the reheated slabs to said mill for reduction to barstherein, means for delivering said bars from said mill to a hot strip mill for reduction to hot strip therein, means for changing the rolls of said strip mill to cold rolls, and means for feeding said hot rolled strip to the cold strip mill thus formed for cold rolling therein.

Il. Apparatus for hot and cold rolling metal,

.comprising a mill for rolling ingots into slabs,

means for reheating said slabs, means for returning the reheated slabs to said mill for reduction to bars therein, means for delivering said bars from said mill to a hot strip mill for reduction to hot strip therein, means for'iorming the hot stripl into coils, means for changing the rolls of said strip mill to cold rolls to form a cold rolling mill, an uncoiler` at one end of the strip mill, and a' reel at the opposite end of the strip mill, whereby hot rolled strip from said coils disposed in said uncoiler is rolled in said cold rolling mill and wound on said reel.

5. Apparatus for hot and cold rolling metal, comprising a mill for rolling ingots into slabs, means for reheating said slabs, means for returning the reheated duction to bars therein, a table for feeding said bars from said' mill to a hot strip mill, a delivery table for receiving hot strip from said strip mill, each of said tables having a removable section adjacent the strip mill, an uncoiler mounted below said removable feed table section, a cold reel mounted below said removable delivery table section, a hot coller at the opposite endof said delivery table, means for changing the rolls of the strip mill to cold rolls to form a cold rolling mill, and means for removing said table sections and for delivering coils of said hot rolled strip to said uncoiler for cold rolling in said cold rolling mill'.

6. Apparatus for hot and cold rolling metal,

comprising a mill for rolling ingots into slabs, v

a shear for said slabs, means for reheating the sheared slabs, means for returning the reheated slabs to said mill for reduction to bars therein,

said shear being adapted to shear said bars,

slabs to said mill for recomprising an entry table, means for delivering versal mill at the delivery end of thetable for hot'rolling equipment hot rolled strip to'the cold strip mill thus formed means, means for conveying piles of slabs from' for cold rolling therein. the piler to a position adjacent. said furnace, 15. Apparatus for hot and cold rolling metal, meansfor` feeding the slabs into the furnace1 comprising an entry table, means for delivering to reheat them before' returning 'them to said ingots thereto, a reheating furnace beside the entry table for reduction to bars in said uni- 5 table, a reversing universal mill at the delivery versal mill, a strip mill at the delivery end of end of the table for reducing the ingots to slabs, the run-Out table fOr IOllng Said bars into hot a run-out table for the slabs, a shear associated strip, said strip mill having interchangeable with the run-out table for shearing the slabs, equipment for hetend cold rolling, the delivery transfer means beside said'run-out table for end of said run-out table being provided with 10 removing sheared slabs therefrom, means for a removable section, anuncoiler mounted below conveying the removed slabs to said furnace to said table section, a coiler for receiving said hot reheat'them before returning them to said entry Strip from Said strip mill, 'a delivery table extable for reduction to bars in said universal mill, tending from the strip `mill to the coiler and said shear being adapted to shear the bars, a having a removable section adjacent the mill, 15 strip mill at the delivery end of the run-out a cold reel mounted below said delivery table table for rolling said bars into hot strip, said section, pickling apparatus, and means for constrip mill having interchangeable hot and coldV veying coils of strip from the coiler to the pickrolls, the delivery end of said run-out table beling apparatus and for conveying pickled coils ing provided with a removable section, an unto said uncoiler when said table sections are re- 20 coiler mounted below said table section, a coiler moved and cold rolling equipment is substituted for receiving said hot strip from said strip mill, .for the hot rolling equipment of the strip mill a delivery table extending from the strip mill whereby to cold roll the strip. to the coiler and having a removable section 17. The method o1A rolling metal comprising adjacent the mill, a lcold reel mounted below rolling blanks in a mill to form work pieces, con- 25 said delivery table section, and means for conveying work pieces while hot from said mill diveying coils of said hot rolled strip to said unrectly to a hot strip mill to reduce themito strip, coiler whensaid table sections are removed and Vcoiling the hot strip, continuing the rolling of cold rolls are substituted for the hot rolls of blanks in said rst mill after said hot strip rollthe strip mill whereby to .cold roll the strip. ing is iinished, exchanging 16. Apparatus for hot and cold rolling metal, ment necessary for hot rolling for that needed for cold rolling, cold rolling the hot rolled strip in the cold strip mill thus formed while blanks ingots thereto, a reheating furnace in cooperaare being rolled in said first mill, returning said tive relationship with the table, a reversing uniingots to slabs, a run-out table cold rolling i! ilnished, and repeating this cycle for the slabs, a shear associated with the runof rolling whereby substantially all of the appaout table, transfer means beside said run-out ratllS iS maintained in Substantially 601115111110115 table for removing sheared slabs therefrom, a operation. slab piler receiving slabs from said transfer reducing the the strip mill equip- 3o to the strip mill after said u

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