US933996A - Casting rolls. - Google Patents

Description

J. L. LEWIS. CASTING ROLLS. APPLICATION FILED JAN. 24. 1906.

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Patented Sept. 14, 1909.

2 SHEETS-SHEET 1.

J. L. LEWIS.

CASTING ROLLS. APPLICATION FILED JAN. 24, 1906.

933,996, Patented Sept. 14,1909. 2 sums-suns!- 2. H52. Flllfiwrrussszs:

' To all whom it. may concern:

'UNITED sanrns JOHN L. LEWIS, OI PITTSBUBG, PENNSYLVANIA.

cas'rme ROLLS.

Specification of Letters Patent.

Patented Sept. 1a, 1909.

Application filed January 24, 1906. Serial No. 297,706.

Be it known that I, JOHN L. Lewis, residing. at Pittsburg, in the county of Allegheny of sand loam having a matrix for the journal at one end of the roll, a drag also formed of loam sand and having a matrix for the other roll journal and also having the necessary sprues or passages for the inflow of molten metal, and one or more chilling cylinders formed of cast iron and arranged between the cope and drag. These chilling cyllnders which are now made witha uniform thickness of wall are provided at their ends with radial lugs which are sometimes continuous forming laterally projecting flanges as shown in Figure 2. As these lugs or flangesare employed only for the purpose of connecting the chilling cylinders to the cope and drag and to other chilling cylinders when two or more such cylinders are employed, they are made of only sufficient thickness to" afiord the desired strength and rigidity for coupling the several parts together. The mold constructed as described is arranged vertically and the molten metal enters through the drag rising up through the latter, and the chilling cylinder to the cope. As the molten metal comes into contact with the almost cold me tallic surface of the chilling cylinders a thin skin or. shell is formed on and completely IIVlOSlllg the mass of molten metal which when cold will form the roll and the chill- I ing cylinders become heated and expand proportional to the degree of heating.

I have found that the chilling cylinders are subjected during the casting of the roll to some force which causes a peripheral enlargement of the cylinders, the enlargement being greater at the ends. This enlargementproduced during casting does not entirely disappear after a casting has been made but the end portions are permanently enlarged. As this enlargement occurs after each casting, it results that although each increment is small the cylinders Wlll soon assume an hour-glass shape as shown at a in Fig. 1. This expansion of the cylinders seems to be due'to an irregular heating of the chilling cylinders or to an ununiform action of the heat on the cylinder. VVhatever may be the cause of the irregular expansion of the chilling cylinders and the incremental enlargement of the ends thereof,

the deformation of the cylinders causes a considerable loss in defective castings. As

the thin shell formed on the roll surface on contact of the molten metal with the chilling cylinder condition by the fluid interior of the casting, it will have but little strength, so that when the ends of the chilling cylinder exand outwardly leaving the thin' skin or shell unsupported laterally or crosswise the pressure of the fluid column will cause a bulging and very frequently a rupture of this shell diametrically on a plane with the end portions of the cylinder as shown at b in Flg. 1. Where two or more chilling cylinders are employed the double bulging diametrically on a plane with the adjacent ends of the chilling cylinders seems to subject the thin shell to such longitudinal strains that the ruptures are peripheral as shown at c Fig. 1.

' The present invention has for its object an equalization of the rate of expansion ofall parts of the chilling cylinder or cylinders, thereby maintaining a lateral support at all points for the thin shell or skin first formed by contact of the molten metal with the chilling cylinders. This equalization may be attained either by retarding the expansion of the end portions of the chilling cylinders or accelerating the rate of expansion of the waist portion or portions of such cylinders by the application of heat thereto. -The .invention is hereinafter more fully described and claimed.

In the accompanying drawings forming a part of this specification Fig. 1 is a sectional elevation of the usual form of mold for casting a chilled roll, showing the latter in position in the mold and illustrating the results of the unequal expansion of the chilling cylinders. Fig. 2 is an enlarged secment, and Fig. 6 isa sectional elevation showing two chilling cylinders of the form shown in Fig. 3 arranged together. for the production of a long roll.

will be kept in a highly heatedconstructed or by proporti V In the practice of my invention'I provide" means whereby the expansion of the ends of the chilling cylinder may be retarded or that of the waist. or middle portions of cylinders 'may be accelerated, such'retardation or acceleration bein so regulated that the rate of expansion sha' be the same orsubstantially the same at all points of the'cylinders. The retardation or acceleration may be efiected .in many ways, as by the-application of a cooling or heating medium to the respective ing the thickportions of the chilling cyzlniuders as new ness of the wall of -the chil ing cylinder at certain points. -This latter method which maybe carried out either by reducing the .thickness of the wall at and adjacent to the waist of the'cylinders as shown in Fig. 2, or by increasing the thickness of the end .portions of the cylinders, is for many reasons preferred, and of these two alternative steps the increasing of the end portions of the cylinders is pre rred.

As shown in Fi s. 3, 4, 5, and 6, the; required thickness 0 wall at the ends of the chilling cylinders can be attained by increasing the thickness and radial extension of the flanges 2 at the ends of the chilling cylinders. The amount of metal thus added at the ends'and adjacent portions of the cylinders is such that by the time the heat from the molten metal has diffused equally through the end portions, the waist portion will have been raised to the same'temperature,and the expansion due to such heating will. be the same at all points, and the .relative internal dimensions will be preserved which is-the purpose of the invention. As shownin Figs. Sand 6 the added metal may project with considerable abruptness from;

' the body ofthe cylinder or may extendwith a more or less radual decrease in thickness toward the waist of cylinder as shown in Figs. 4 and 5. In the construction shown-in Figs.- 3, 4, and 5 the added metal which is largely in excess of that required for chilling purposes is disposed in massive flange form and clamps can be readily applied thereto, as is the present practice, for connecting the chilling cylinder to the cope and draw and another cylinder when twoor more are reing chilled rol iguired. When the metal addedas to form a wall gradually decreasing in thick ness towardthe waist, fnotches 3 are provided for the reception of the-fiends of the clamps, j As shew in Fig. 2 the cylinders now in use can be so altered as y decreasing the thickness of the wall of the waist portion as to--insure a practically equal-rate of expansion of all portions of the cylinder.- The retardation of the expansion of theends of the cylinderscan be effected by applying a cooling fluid to such portions, and

an acceleration of the expansion of the waist of the cylinder can be .had by applying a heating medium as gas jets to such waist portion.

Practical use of 'my'inve ntion hasshown that by properly proportioning the thickness of the metal at the ends and waist porvtions of the chilling cylinder or cylinders the rates of expansion .-will be practicalsl the same at all points and the chilling cy 'nder or cylinders will retain their cylindrical shape and hence there willnot be any bulg-- in or swelling'out of-any portion of the rofi formed in such mold. j

' While "I have described with considerable particularity forms of apparatus forcarry-- mg out my improved method, no claim is made herein to such apparatus as the same forms the subject matter of application filed June 16th, 1906, Set. lid-391,976. I claimherein as my invention: 1. As an improvement in the art of casting chilled rolls, the method herein described which consists in preventing an irregular In testimony whereof, I havejhereuntoset my hand. j

JOHN L. LEWIS. Witnesses:

CHARLES BARNETT, Morrow JoHNs'roN.

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