US2012706A - Method of rolling metal strip - Google Patents

Description

Aug. 27, 1935. F. c. BIGGERT. JR 2,012,706

METHOD OF ROLLING METAL STRIP Filed Jan. 20, 1954 l 1. i I 2 fi 3 I :1

mm r1 11 l|= l l LTH IT WITNESSES i I L I Patented Aug. 27, 1935 UNITED STATE s PATENT OFFICE METHOD OF ROLLING METAL STRIP Florence C. Biggert, Jr., Grafton, Pa., assignor to United Engineering & Foundry Company, Pittsburgh, Pa., a corporation of Pennsylvania Application January 20, 1934, Serial No. 707,497

3 Claims.

This invention relates to the rolling of metal strip, and more particularly to the rolling of mapass the slabs from which the strip is produced I through spreading passes before the regular strip rolling operations are inaugurated. The

reason for this is that they do not have any slab mills available which are capable of rolling slabs of suflicient width to produce the width of strip desired. To meet this situation'it is the pravailinvention and illustrating the different shapes which a slab takes when passed therethrough; Fig. 4 a view similar to Fig. 2 of the mill shown in Fig. 3; and Fig. a plan view of a mill layout using a tandem arrangement of roll passes for practicing the invention.

Referring in detail to this drawing, the numeral I designates a roll stand forming what is shown as a broadside spreading pass, and the numerals 2 and 3 a series of reducing and edging ing practice to pass the slabs as they are taken from the slab mills sidewise through what is termed a broadside pass to increase their width.

After leaving this pass the slabs are rotated 90 and then entered into the first regular pass of the strip roll, which may be either a continuous or universal type of mill. k Frequently the spreading required is relatively large as compared to the original width of. the

slabs, and the regular shape .of the slabs considerably deformed. This irregular deformation occurs mostly at'the comers of the slabs where there is insuflicient metal to prevent the edges flowing laterally. Suchcorner spreading, also is usually diiferent at thetwo ends of the slabs. In addition, the front end is usually convex in shape, while the tail end is concave when the slabs come out of the spreading pass. Because or this the problem of bringing the edges of the slabs back into line after they are spread, which is necessaryin order to control the widths and uniformity of the strip, becomes very diflicult and frequently impossible. Unless these edges are properly aligned the slabs become bent as theypass through the strip mill due to the unequal work which the edging rolls have to perform, and are most difflcult to handle.

It is an object of this invention to overcome such difliculties' in wide strip mills by diagonally spreading the slab in place of the usual broadside spreading, whereby the total deformation is greatly decreased.

Byway of illustrating the invention and its improvement over theprior, practice, reference may be had to the accompanying drawing,of

which Fig. 1 is a plan view of a commonform of strip mill showing difierent shapes which the slab takes as it is passed through such a mill; Fig. 2 a side elevational view of the mill shown in Fig. 1; Fig. 3 a view similar to Fig. 1 of a strip mill constructed in accordance with this strip is bent as shown at d roll stands respectively which, with the spreading rolls, comprise a continuous strip mill of the type commonly used in producing strip and sheet material. As illustrated at a in Fig. 1, in accordance with the present practice a slab 4, which is too narrow to produce the width of strip desired, is first passed s'idewise one or more times through the spreading pass I to increase" its width. During this operation, as shown in a somewhat exaggeratedfashion at b, the corners of the slab are normally spread laterally more than the sides due to the unsupported condition of the metal at those points, and such deformations as a rule are more pronounced at the forward end than the rear end of the piece. Furthermore, the forward end usually becomes somewhat convex in shape,

while the rear end becomes somewhat concave,

and these conditions become more aggravated with increased spreading. v

When this spreading operation is completed the slab is turned around 90, as shown at c, and passed into the first stand 2 of reducing rolls'.-- But in order -'toproduce a uniformly shaped strip its s'pdeedges, which were irregularly distorted in the spreading pass I, have to be brought back into line. This is accomplished by the edging rolls in the edging stands 3. However, where the sides are too greatly distorted this problem becomes too difiicult to cope with and the slab is wasted, and evenat its best, due to the fact that the edging rolls on the side of the mill through which the convex edges of the slab pass have to do more work than those on the other side, the as it emerges from the edging rolls. This bending, as will be readily appreciated, makes for great difiicult in. passing thestrip through the succeeding roll stands, in that it complicates and slows up the rolling operation and militates against the production of a strip. having straight, smooth edges, which is desired.

In accordance with this invention to overcome these difiiculties, as illustrated in Figs. 3 and 4, a multiple pass spreading roll stand 5 is arranged in front-of the regular reducing passes of the mill which may consist of a series of horizontal and vertical roll stands 6 and I, or a universal mill. This multiple pass spreading roll stand is made somewhat wider than the customary broadside spreading roll stand, and the slab 8, as shown at m in Fig. 3, is first entered in the lower pass of such roll stand along one of its diagonals. When rolled in this fashion it spreads the slab into a not shown in detail, any suitable form of manipulating apparatus l0 may be used for handling the slab and passing it back and forth through this mill until it is spread sufiiciently, which may require one or more passes in each direction.

- When these spreading operations are completed the slab is rotated 45, as shown at q, and then again passed through the lower rolls of the spreading stand to take out any roughness in it. It will be understood of course that instead of the slab being rotated as stated to make the entries required with the least amount of turning they may be rotated in the opposite direction, all of which is contemplated by the appended claims. On leaving this latter pass the slab is passed directly as indicated at r into the strip mill proper 1 through which it then moves with accurate uni formity as its edges, while deformed slightly at the corners, are symmetrical with respect to the center line of the edging rolls sothat relatively little difliculty is encounteredin correcting the deformation. It will be appreciated that the lastmentioned spreading pass operation may be dispensed with, as such is employed merely to smooth out the stock in preparation for its entries in the mill.

As illustrated in Fig. 5 the invention may also be practiced by using a. series of roll stands consisting of spreading stands I I and I 2, and an edging stand l3, which are arranged in front of the first mill stand M, the slab being rotated as indlcated before it is entered in each of these stands.

Among the advantages ofinvention, as will be apparent to those skilled in the art, it permits the use of spreading operations to a greater extent than is permissible in the customarily used broadside spreading pass as it greatly reduces the irregular deformation at the comers of the slab, and as such deformation as may occur is symmetrical and therefore more easily corrected. As a result strips having accurately straight edges may be rolled wtih a minimum of difiiculty and wasted material.

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

I claim:

1. The method of rolling metal strip from a slab having an insuflicient width to produce the width of strips desired comprising alternately spreading the slabs uniformly along its two diagonals until the proper width is obtained, straightening its lateral edges by passing it through an edge working device and then reducing and elongating the slab in a continuous mill until the desired thinness is obtained.

2. The method of rolling metal strip from a slab having an insuflicient width to produce the width of strip desired comprising passing such slab diagonally through a spreading pass, turning it 90 and passing it through said spreading pass again along its opposite diagonal, then turning it 45 and passing it through a series of edging and reducing roll passes.

3. The method of rolling metal strip from a slab having an insuflicient width to produce the width of strip desired, comprising passing the slab one or more times through a spreading pass along one of its diagonals, rotating it 90 after each such pass and passing it an equal number of times back through said spreading pass along its opposite diagonal, and then passing it in succession through a series of edging and reducing passes to straightendts edges and reduce its thickness.

FLORENCE C. BIGGERT, Jn.

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