US1829339A

US1829339A - Process of rolling metal

Info

Publication number: US1829339A
Application number: US378906A
Authority: US
Inventors: Michael C Corrigan; David E Jenkins
Original assignee: Republic Steel Corp
Current assignee: Republic Steel Corp
Priority date: 1929-07-17
Filing date: 1929-07-17
Publication date: 1931-10-27
Anticipated expiration: 1948-10-27

Description

1931- M. c. CORRIGAN ET AL 1,829,339

PROCESS OF ROLLING METAL Filed July 17, 1929 gwwmtow M/chqe/ C. Ccrr/gan 'Dawd t. Jenkms Patented Oct. 27, 1931 UNITED STATES PATENT OFFICE,

MICHAEL O. COBRIGAN, .OF MASSILLON, AND DAVID E. JENKINS, F CANTON, OHIO, AS- SIGN ORS, BY MESNE ASSIGNMENTS, TO REPUBLIC STEEL CORPORATION, OF YOUNGS- TOWN, OHIO, A.CORPORA.TION OF NEW JERSEY PROCESS OF ROLLING- METAL Application filed July 17, 1929. Serial No. 378,906.

This invention relates in general to the continuous rolling of iron, steel and other metals,

- and more particularly to a method of rolling metal, whereby certain predetermined contours are given to the metal in successive passes through a series of pairs or stands of rolls.

It has heretofore been proposed to roll sheets by a method wherein the sheets are provided with convex upper and lower surfaces, the degree of convexity of these surfaces being reduced in successive passes until these surfaces are substantially flat or parallel with each other. Such a method of rolling sheets has been disclosed in the reissue patent to Tytus, No. 16,884.

In rolling sheets according to the method described in the aforesaid patent, a number of factors are taken into consideration, such as the contour of the rolls, the-composition and springiness of the rolls, the spacing of the rolls, or screw, the temperature of the rolls, and the shape, composition and temperature of the piece which is being rolled. These factors are so controlled that a piece of predetermined contour and temperature is engaged in each stand of a series of pairs of rolls, arranged to successively engage the piece and to reduce it to the and flatness.

r In starting with a piece, such for'e'xample as a sheet bar or slab, and attempting to roll it into a thin wide sheet by the aforesaid process, the bar would first be heated to a predetermined temperature and then passed successively throu h each pair of rolls. If the rolls are all of the same size, and have concave working faces, the degree of concavity of these faces must decrease in each successive pair of rolls, in order that the convexity of the surfaces of the piece may be properly reduced.

' If the piece is not reheated while it is being elongated, it resists deformationfor reduction to an increasing degree in each successive pair of rolls, withthe result that the rolls are-sprung to a greater extent than they I would be if the piece was'maintained at an elevated temperature, as by heating it between passes.

desired gauge This increase in spring of the rolls, which I extremely difficult to determine how muchshallower the rolls should be ground to compensate for this increasing spring in successive pairs of rolls. It is apparent therefore that the efi'iciency of the successive pairs of rolls in reducing the piece decreases, and this decrease in efliciency becomes more apparent as the finishing passes are approached.

These conditions may be corrected to some extent by increasing the spacing of the rolls, or screw, or by heating or cooling the rolls to control the active pass. Increasing the spacing of the rolls necessitates a larger number of stands or pairs of rolls to obtain the active pass by heating or cooling the rolls is an uncertain and diificult procedure.

where a piece having convexsurfaces isbeing rolled, the greater part of Moreover,

the work .done by the rolls in each active pass is on the center of. the piece, and in the final passes, it becomes necessary to watch the operations very carefully .to avoid undue stresses in the center of the piece, which have a tendency to cause buckling or riifiing of the piece. This difliculty becomes especially apparent in the rolling extremely wide sheets.

It is a primary object of our invention to provide a-method of rolling metal, whereby a piece, such as a sheet bar orv slab, of predetermined contour is reduced in successive of extremely thin and passesthrough a'series of stands or pairs of rolls, and wherein the efliciency of the rolls in reducing the piece is not affected by decrease in the temperature of the piece.

Another object of the invention is to provide a method of rolling metal, whereby the work done by the rolls in each active pass is uniformly distributed over the piece, so that undue stresses in the piece are avoided, and the flow of the metal is made more uniform, resulting in improved grain structure and improved physical properties.

A further object of the invention is to provide a method of rolling metal, whereby sheet or strip of uniform width, gauge and fiatness may be produced from sheet bars, slabs and the like by a continuous process.

In accordance with the invention, ingots, after removal from the soaking pit, are reduced in a blooming mill or in a slabbing mill, and out up to provide pieces having the crosssectional contour shown in Fig. 1, or. the cross-sectional contour shown in Fig. 6 of the accompanying drawings, forming a part of this specification.

As shown in Fig.1, the piece is of such contour that the upper and lower surfaces a and b thereof are slightly concave. In actual practice, the degree of concavity of these surfaces is such that the thickness or depth of the piece at the center is from .025" to .125" less than the thickness or depth of the piece at the side edges thereof. If. for example, the piece is about 30 inches wide and about 3 inches thick at the edges. the thickness of the piece at the center .will be approximately 2 These dimensions are'given by way of example only, and are not intended to restrict the scope of practice of the invention, the P scope of the invention being defined by the appended claims.

We may begin with a piece having the cross-sectional contour shown in Fig. 6. In this case, only one of the surfaces, preferably the upper surface a of the piece is concave, while the lower surface at is substantially flat.

If desired, the upper and lower surfaces of the piece may be concaved in different degrees, and the side edges of the piece also concaved to a slight degree. as shown in Figs. 1 and 6. The corners of the piece, i. e... the junction of the upper and lower surfaces with the side edges, are preferably rounded.

In anycase, the piece is preheated to a temperature sufficiently high to permit it to be rolled down to the desiredgauge and flatness without reheating, but nothing 'herein is to be construed as limiting the invention to a method wherein the piece is not to be reheated after its initial heating. Exigencies of rolling may make it desirable to rehea't the piece atom or more points during the rolling operations.

If the piece shown in Fig. 1 is to be rolled. it is passed successively through'a series of pairs of rolls having convex or crowned working faces designed to successively reduce the degree of concavity of the upper and lower surfaces of the piece. The reductions of the concavity of the upper and lower surfacesof the piece in the successive stands or pairs of rolls is illustratedin exaggerated form in Figs. 2 to 5 inclusive of the drawings. In the last stand of rolls, as

shown in Fig. 5, the active pass of the rolls is such that the piece emerges from these rolls with the upper and lower surfaces thereof substantially flat or parallel with each other. lVhere all of the rolls areof approximatey the same size, it will be understood that the working faces of each pair of rolls are convex or crowned to a greater degree than the faces of the succeeding pair of rolls, and in the last stand or pair 0 rolls, the facesof the rolls are crowned only sufficiently to compensate for the spring of the rolls during the passage of 'the piece therethrough.

If the piece shown in Fig. 6 is to be rolled, itis passed successively through a series of pairs of rolls, the working faces of the upper roll of each pair beingconvexed to successively reduce the degree of concavity of the upper surface of the piece. The corresponding lower roll in each pair is crowned only sufliciently to compensate for the spring of the rolls during the passage of the piece therethroughu The lower surface of the piece is maintained as nearly flat as possible. The reduction of the piece in successive stands of rolls is illustrated in exaggerated form in Figs. 7 to 10 inclusive of the drawings. In the last stand of rolls, the active ass is such that the piece emerges from these rolls with the upper and lower surfaces thereof substantially flat or parallel with each other. I

It will be apparent in rolling a piece by our method, that where the'piece is being rolled without reheating it, the increasing spring of each successive pair of rolls is actually utilized in the rolling operation, for increasing the spring of the rolls is equivalentto decreasing the convexity or crown of the rolls. In thus utilizing the increasing spring of the rolls,=the method of rolling is made more efficient.

It will also be apparent that the work done by'the rolls in each active pass is uniformly distributed over the piece, thereby avoiding localizedstresses, and resulting in a product having improved grain structure and improved physical properties.

The term piece, as used in this specification, refers generically to a single piece, such as an ingot, slab or sheet bar, or to other products of rolling, such as a pack of sheets.

The term stand, as used in this specification, refers to apair of rolls through which the piece passes during the rolling process,

that the features and advantages of the present invention will be readily apparent to those skilled in the art, and it will of course be understood that various changes may be resorted to without departing from the spirit or scope of theappended claims.

Claims:

1. A continuous process for reducing hot metal to sheet form in successive stands of rolls, which consists in passing a piece of metal from one stand to another successively and controllingthe active pass of the rolls in each stand so as to form for the next stand a piece of slightly greater radiusof concavity curvature than the active stand.

2. A continuous process for reducing wide and thin metal to sheet form in successive stands of rolls, which consists in passing a piece of metal from one stand to another successively and controlling the active pass of the rolls in each stand so as to form for the next stand a piece of slightly greater radius of concavity curvature than the active pass of said next stand.

3. A continuous process for reducing hot metal to thin wide form in successive stands of rolls which consists in passing a piece of metal through one 'stand of, rolls after another successively and impressing upon the piece by the active pass of the,first and each succeeding stand of rolls, a cross-sectional pass of said next shape wherein opposite surfaces of the piece are concave, the degree of concavity decreasing in each succeeding stand.

4. A continuous process for reducinghot metal to thin wide form in successive stands of rolls which consists in passing a piece of metal through one stand of rolls after another successivel and impressing upon the piece by the active pass of the first and each succeeding stand of rolls, a cross-sectional shape wherein at least one of the surfaces of the piece is concave, the degree of concavity decreasing in each succeeding stand.

5. A continuous process for reducing hot metal to sheet form in successive stands of rolls, which consists in passing a piece of metal from one stand to another successively and controlling the active pass of the rolls in each stand so as to form for the next stand a piece having a slightly greater degree of concavity than the active pass of said next stand. 0 5 v 6. A continuous process'for reducing wide and thin metal to sheet form in. successive stands of rolls, which consists in passing a piece of metal from one stand to another successively and controlling the active pass of the rolls in each stand so as to form for the next stand a piece having a slightly greater metal through one stand of rolls after an other successively and impressing upon the piece by the active pass of the first and each succeeding stand of rolls, a cross-sectional shape wherein the opposite surfaces of the piece are entirely concave, the degree of concavity decreasing in each succeeding stand.

8. A continuous process for reducing hot metal to thin wide form in successive stands of rolls which consists in passing a piece of metal through one stand of rolls after another successively and impressing upon the piece by the active pass of the first and each succeeding stand of rolls, a cross-sectional shape wherein at least one of the surfaces of the piece is entirely concave, the degree of concavity decreasing in each successive stand.

9. A continuous process for reducing hot metal to sheet form in successive passes through rolls, which consists in passing a. piece of metal through each pass successively and controlling each active pass so as to form for the next pass a piece of slightly greater radius of. concavity curvature than that formed by the next active pass.

10. A continuous process for reducing wide and thin metal to sheet form in successive passes through rolls, which consists in passing a piece of metal through each pass successively and controlling each active pass so as to-form for the next pass a piece of slightly greater radius of concavity curvature than that formed by the next active pass.

11. A continuous process for reducing hot metal to thin wide form in successive passes through rolls which consists in passing a piece of metal through each pass successively and impressing upon the piece by each active pass, a cross-sectional shape wherein opposite surfaces of the piece are concave, the degree of concavity decreasing in each successive pass.

12. A continuous process for reducing hot metal to thin wide form in successive passes through rolls which consists in passing a piece of metal through each pass successively and impressing-upon the piece by each active pass, a cross-sectional shape wherein at least one of the surfaces'of the piece is concave, the de ee of concavity decreasing in each successive pass.

13. A continuous process for reducing hot metal to sheet form in successive passes through rolls, which consists in passing a piece of metal through eac pass successively and controlling each active for the next pass a piece having a slightly greater degree of concavity than that formed by the next active pass.

14. A continuous process for reducing wide and thin inetal to sheet form in successive pass so as to form passes through rolls, which consists in passing a piece of metal through each pass successively and controlling each active pass so as to form for the next pass a piece having a 5 slightly greater degree of concavity than that formed by the next active pass. p 15. A continuous process for reducing hot metal to thin wide form in successive passes through rolls which consists in passing a piece of metal through each pass successively and impressing upon the piece by each active pass a cross-sectional shape wherein opposite surfaces-of the piece are entirely concave, the degree of concavity decreasing in each successive pass.. I

v 16. A continuous process for reducing hot metal to thin wide form in successive passes through rolls which consists in passing a piece of metal through each pass successively and impressing upon the piece by each active pass a cross sectional shape. .wherein atleast one of the surfaces of the piece is entirely concave, the degree of concavity decreasing in each successive pass.

17. A continuous process' of converting metal into sheet form which comprises repeatedly subjecting a piece of metal initially of substantially rectangular transverse crosssection and having one concave surface to roll no pressures exerted on opposite surfaces of the piece, one of-which surfaces is the said concave surface, and gradually and pro'gressively increasing the radius of curvature of the said concave surface, until said surface is substantially flat.

18. A continuous process of converting metal into sheet form which comprises repeatedly subjecting a piece of metal initially of substantially rectangular transverse cross- 40 section, and having concave opposite surfaces, to roll pressures applied to the concave surfaces, and graduall and progressively increasing the radius 0 curvature of the said concave surfaces until the said surfaces are substantially parallel.

In testimony whereof we aflix our signa tures.

MICHAEL C. CORRIGAN. DAVID El JENKINS.