US1988679A - Rolling mill - Google Patents

Description

Jan. 22, 1935. s. BADLAM 7 1,988,679

ROLLING MILL Filed Nov. 25, 1931 WITNESSES INVENTOR WWW. 3%

Patented Jan. 22, 1935 Application November 25, 1'93'1, "Sria'k' 6.257%,277-Q; 7 40mins. (ciaoa i invention relates tcreumgmms, and particularly mills for rolling p1ates,- sr 'e1py sheets, strip; and other" sheet-like products";

i the rolling mill art bdthhbt aiid fc bld rolling, it is' wll' known that On eT Of the factors influencing the shape of a deuvereapiece 'i's'th uneven distribution of heatalon'gthe length of the roll body. This has'the effect of making the shape .ofth'e active pass, that is to say, the" shape of the pass while the piece is engaged by the rollsyd-ifierent from thesha'pe of thepasswhen the rolls are cold and no piece is engaged by them, as war as" different at successive stages of the rolling operation.

This change of shape due to heat is comparatively small in the case of sections such as squares, rounds, shapes,- etc., in which the width is not great in proportion to the thickness, but

, is of material importance in the case of plates,

and becomes a dominant factor in the case of sections such as sheets, strips, skelp, and the like, in which the width is great in proportion to the thickness.

The change in shape of rolls due to heat may arise from two among other causes; first, from heating of the necks, due to hearing friction which causes the ends of the roll body to expand more than the center of the roll body. Second, the heating of the center of the roll body due to the heat derived from hot metal passing through the rolls, or evolved due to the mechanical work done upon the metal. The first causes a thinning of the edges of the sheet due to the expansion of the ends of the rolls, and the second causes a thinning of the center of thesheet due to the expansion of the center of the rolls.

Several expedients have been used in the past to overcome the effect of this uneven heating, such as turning the rolls to a non-cylindrical shape in the cold so that, after the rolls have been in use for a period of time and become heated, the shape of the active pass will become truly cylindrical. This may take the form of making the cold rolls either hollow or else crowned in the centers, according to whether the effect of the heating is to puff up the centers or to expand the ends of the rolls. Another expedient is to use only a minor part of the body of a roll as a working face, whereby the conduc-' tion of heat from the bearings is decreased and made substantially uniform throughout the portion used as a working face. Still other expedients are the application of a cooling medium, such as water, on portions of the body of a roll, or on its hearings, to decrease the heat thereof,

are repl cates or gas-p1? oiT- on p tions" of ran" my" tb increase its heat a'ncrb sequent expansion. I I H A The' objctof t'l'i' present nvention is tofpiovice mproved if! s'fo'r dissipatihgithe sea or; roll's andsubstan 1y preventing its new from the eers to' t emes and'vi illustrated iiifthe accompa y g; draw ng, r WhichFig. 1 is facevwW' ofa air of working rolls for a mill for rolling sheetJil n-i metalain I Fig. 2 a face view of a set of workingandbacking rope for barred-up: mill for purpose.

In the practice of this invention its stated object is accomplished by providing each end of a roll body, between its working face and neck portions, with exposed attenuated heat-dissipating surfaces. These surfaces preferably take the form of radially-disposed annular or helical fins or vanes, the exposed surfaces of which are materially greater than the working face of the roll for a. corresponding portion of its length. When heat-dissipating fins are used, they may be formed integrally with the roll, or they may be in the form of disks of copper or other good heat-conducting metal suitably attached to the roll between its working portion and necks. The cooling of these heat-dissipating surfaces may be either by means of the air surrounding them or by the use of a cooling medium such as air, water or oil applied to them. 7

In Fig. 1 of the drawing there is shown a pair of working rolls having working portions 1 and necks 2, between which there are a plurality of annular fins 3 forming attenuated heat-dissipating surfaces. If desired, these surfaces may be continuously cooled by means of a cooling medium, such as Wateror oil, flowing on them from a header 4 connected to a pipe Sleading from a suitable source of supply. The fins 3 being arranged in a zone or section of the rolls between their working portions and necks, afford surfaces for dissipating .heat flowing eitherfrom the bodies into the necks or from the necks into the bodies of the rolls, depending upon well known variable conditions of rolling. I

In Fig. 2 there is shown abacking-roll mill comprising working rolls and backing rolls 11. In mills of this type pressure is applied to the rolls through the necks 12 of the backing rollsQand accordingly frictional heat is generated in the necks of the backing rather than in those of the working rolls. In this case the backing rolls are provided with fins 13 between their necks and cen-' tral working portions, such fins forming attenu- 2 i n v ated heat-dissipating surfaces particularly for dissipating heat generated in the necks of the rolls. In this embodiment of the invention 'fins 13 are shown as being enclosed in fluid-tight casings 14 into which cooling fluid is introduced through pipes 15 and withdrawn through pipes 16. The fins are thus kept in continuous contact with the cooling medium circulating within the casing. By providing helical fins such as illustrated, the cooling medium may be causedto circulate'in the casings ina direction counter. to that of the flow of heat from one to another portion of a roll, although annular fins such as shown in Fig. 1 may be similarly used inscasings 14.

Working rolls are shown in Fig. 2 as being provided with a modified form of fins 17, these being disks of copper or othergood heat-conducting metal suitably attached tothe rolls between their working surfaces and necks. Manifestly stood that, within the scope of the appended claimsythe invention may be practiced otherwise than as illustrated and. described.

I I'claim: I

1. In a rolling mill, a roll having a central work.-

ing portion, bearings at its ends, and provided between its working portion and bearings with attenuated heat-dissipating surfaces, casings enclosing said heat-dissipating surfaces, and means for circulating a cooling medium through said casings and in contact with said surfaces.

2. In a rolling mill, a roll having a central working portion, bearings at its ends, and provided between its working portion and bearings with attenuated heat-dissipating helical fins, casings enclosing said fins, and means for circulating a cooling medium through said casings and in contact with said fins.

3. In a rolling mill for rolling thin wide flat metal, a pair of rolls each having a central working portion, bearings at its ends, and provided between its'working portion and bearings with exposed attenuated surfaces for dissipating heat flowing-to and from the working portion and bearings of the roll, whereby to inhibit the effect of heat on the active pass formed by the working portion of the rolls.

4. In a rolling mill for rolling thin wide flat material, working rolls and backing rolls, said backing rolls each having a body portion engaging the adjacent working roll and bearings at each end, and provided between said body portion and said bearings withexposed attenuatedsurfaces for dissipating heat flowing to and from the body portion and the bearings, whereby to inhibit the efiect of said heat on the active pass formed by the working rolls.

STEPHEN BADLAM.

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