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Publication numberUS3754873 A
Publication typeGrant
Publication dateAug 28, 1973
Filing dateFeb 3, 1971
Priority dateJan 17, 1969
Also published asDE2001915A1, US3619881
Publication numberUS 3754873 A, US 3754873A, US-A-3754873, US3754873 A, US3754873A
InventorsM Bills, H Hansen
Original AssigneeSteel Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Cold rolled sheet
US 3754873 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

UNITED STATES PATENTS O U mted "States Patent 11 1 1111 3,754,873 Bills et al. Au 28, 1973 1 COLDROLLED SHEET 319,306 6/1885 Palmer 29/188 9 [75] Inventors: Max E. Bills, Pleasant Hills Borough, 3'0O3'599 10/1961 Rubmw 2 I18 Pa.; Henry J. Hansen, Jr., Portage,

l d. n Primary Examiner-A. B. Curtis 1 Asslsnw United States Steel Corporation, Assistant Examiner-O. E. Crutchfield Pittsburgh AttorneyArthur J. Greif [22] Filed: Feb. 3, 1971 [21] Appl. No.:- 112,362

Related US. Application Data [57] ABSTRACT [62] Division of Ser. No. 792,079, Jan. 17, 1969, Pat. No.

A cold rolled steel sheet or strip has a plurality of 52 U.S. c1. 29/1835 clsely P generally frusmpherical [51 1m. (:1 B2lb 1/28 Substantially shape and height [58] Field of Search 29/1835 180 ss thmughwt its surfm the arithmetic average ness of the surface being between 20 and 400 micro- [56 References Cited Inches- 2 Claims, 4 Drawing Figures PATENTEUMIBZB ms SHEET 2 [IF 2 PATENTEB A0828 I975 SMHIUFZ INVENTORS. MAX E. BILLS AND HENRY J, HANSEN, JR. By I A r tor/ray COLD ROLLED SHEET This application, which is a division of my co-pending application Ser. No. 792,079, filed Jan. 17, 1969, now U.S. Pat. No. 3,619,881 relates to a cold rolled sheet and more particularly to a steel sheet having low projections thereon.

In the manufacture of cold rolled sheets it is necessary to control the surface finish of the product to the required degree of roughness so as to enhance the appearance and the performance of the material in subsequent operations. The required finish is commonly obtained in the final stages of manufacture by rolling the strip between rolls of controlled roughness which impress such roughness generally into the surfaces of the strip. It is thus vitally important that these rolls possess the proper roughness. Conventionally, the roll roughness is attained by carefully shot blasting the prepared roll surface, the depressions and associated peripheral upheaval thus created by particle impingement providing the desired roughness. This operation, however, is difficult to control because of differences in kinetic energy, size and angle of impingement of the shot blast particles. Thus, the resultant roll roughness pattern is characterized by randomness with respect to the shape, size and distribution of the topographical features. It is common practice for the customer to request a particutionship to the true type of surface. In other words, the

same reading by the profilometer may result from surfaces having a substantial difference in appearance and/or a substantial difference in the shape and arrangement of the depressions. Since it is desirable that the surfaces of the strip have the same visual appearance and also that it have the same texture for receiving paint, it is clear that the process and the rolls now in use are not entirely satisfactory.

It is therefore an object of our invention to provide a cold rolled sheet having projections of such shape and arrangement that the visual appearance and surface of the sheet is relatively constant. I

This and other objects will be more apparent after referring to the following specification and attached drawings, in which:

FIG. 1 is a view of a conventional temper rolling mill for rolling sheets;

FIG. 2 is a schematic view showing depressions being generated in the surface of the roll used in producing sheets according to our invention;

FIG. 3 is a magnified view of a replica of the surface of the roll of FIG. 2; and

FIG. 4 is a magnified view of a replica of the roll surface resulting from shot blasting according to the prior art.

Referring more particularly to the drawings, reference numeral 2 indicates an uncoiler from which strip S is uncoiled and passes through a set of rolls 4 to a coiler 6. It will be understood that additional stands of rolls may be used at the entry side of rolls 4. However, the number of stands is not important insofar as our invention is concerned, it only being necessary that the 'known Electric Discharge Machining (EDM) operation, in which bursts of electrical energy 8 from electrode 10 volatilize and remove small amounts of metal from the surface of the roll. This method generates shallow depressions 12 in the outer surface of the roll, thus providing the desired roughening of the roll surface. Most all of the depressions are of substantially uniform shape and depth, and, while closely spaced, are randomly spread over the outer surface of the roll. It will be seen that the depressions 12 are rounded and are substantially frustospherical. FIG. 2 shows only a few depressions 12 for the sake of clarity, but in the finished roll they will be very closely spaced.

The depth and diameter of the depressions 12 may vary over wide limits depending on the desired degree of roughening, this being a matter of selecting the proper electrical parameters for the individual electrical discharges so as to generate the desired degree of roughness in the roll surface. This procedure is well known and presents no problem to the operator. When the depth of the individual depressions is such as to provide an arithmetic average (AA) roughness in the roll surface of about, microinches, as measured with conventional profilometer measuring equipment, the individual depressions associated with such roughness vary approximately from 0.0005 to 0.001 inch in depth and from 0.010 to 0.020 inch in diameter. It will be understood that further variation will occur from these figures because the electrical discharges are compounded on one another and act in this manner to alter the dimensions of the individual roughness features. Despite such phenomena, however, the individual depressions are always rounded and of comparable depth for a given electrical setting of the EDM equipment, and it is from this characteristic that the unique features of the surface finish of our invention are derived. Sharp corners are essentially eliminated. The roughness may vary from approximately 20 to approximately 400 microinches, but in most cases will be between 20 and microinches. Increasing the intensity or size of the electrical discharge increases the roughness and decreasing the intensity or size of the electrical discharges lowers the roughness of the roll surface.

Since the time required to texture rolls to the smoother finishes can become prolonged, it may be advisable in some instances to provide deeper depressions than desired and then brush or otherwise smooth the surface of the roll to obtain a smoother finish. Care must be taken not to substantially alter the shape or other essential characteristics of the EDM type finish.

Since FIG. 3 is an enlarged photograph of a replica made of the surface of a work roll textured by Electric Discharge Machining methods, it represents the ideal strip surface finish obtainable when using our rolls.

' However, the work roll finish is superimposed to a degree over any other finish which the strip being rolled may possess, so that a perfect reproduction of the roll surface may not always be impressed into the steel surface. It is clear, however, that the EDM type of roll surface will generate a strip finish consisting of rounded topographical features of generally consistent shape and size. The regularity of shape and size of the topographical features of the EDM type surface shown in FIG. 3 are evident by contrast with the varying shape and size of the features of the shot blasted surface of FIG. 4.

While one embodiment of our invention has been shown and described, it will be apparent that other ad- 3 aptations and modifications may be made without departing from the scope of the following claims;

We claim:

1. A cold rolled metal sheet having a plurality of closely spaced low projections on at least one side thereof, substantially all of said projections having a generally frustospherical shape and substantially uniform height, said projections having been produced by cold-rolling through opposed rolls corresponding to the texture of the respective sides of said sheet, wherein the the roll surface is between 20 and microinches.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4071657 *Nov 4, 1975Jan 31, 1978Societe Lorraine De Laminage ContinuMetal sheet for drawing
US4111032 *Jul 11, 1977Sep 5, 1978Societe Lorraine De Laminage ContinuProcess for producing a metal sheet to be deep drawn or extra-deep drawn for the fabrication of shaped metal parts
US4553012 *Apr 18, 1984Nov 12, 1985Anderson Alex LFor electric discharge machining the surface of a workpiece
US4841611 *Jul 13, 1987Jun 27, 1989Kawasaki Steel CorporationWork roll with dulled surface having geometrically patterned uneven dulled sections for temper rolling
US5012062 *Jul 18, 1989Apr 30, 1991The United States Of America As Represented By The Administrator Of The National Aeronautics And Space AdministrationArc-textured high emittance radiator surfaces
US5543961 *Jun 10, 1993Aug 6, 1996The United States Of America As Represented By The Administator Of The National Aeronautics And Space AdministrationFar-infrared diffuse reflector
US5780726 *Aug 28, 1996Jul 14, 1998Bethlehem Steel CorporationMethod of determining slope angles of impression walls and depths of impressions on an embossed sheet surface
US5818006 *Dec 7, 1995Oct 6, 1998Ford Global Technologies, Inc.Surface preparation electrical discharge apparatus and method
DE2840702A1 *Sep 19, 1978Apr 5, 1979Centre Rech MetallurgiqueVerfahren und vorrichtung zur qualitaetsverbesserung von stahlfeinblechen
EP0234698A1 *Jan 15, 1987Sep 2, 1987Kawasaki Steel CorporationSteel sheets for painting and a method of producing the same
EP0251759A2 *Jun 30, 1987Jan 7, 1988Kawasaki Steel CorporationSteel sheets for use in forming cans by deep-drawing and ironing
U.S. Classification428/687, 219/69.17, 219/68
International ClassificationB21B27/00, B21B1/22, B23H9/04
Cooperative ClassificationB23H9/04, B21B1/227, B21B2267/10, B21B27/005
European ClassificationB23H9/04, B21B1/22R, B21B27/00R
Legal Events
Mar 31, 1989ASAssignment
Effective date: 19880112