US2501663A - Making cast mill rolls - Google Patents

Description

March 28, 1950 Filed Dec. 29, 1945 F. CORDES MAKING CAST MILL ROLLS 2 Sheets-Sheet l INVENTOR Frank (O/04. 5

March 28, 1950 CQRDES MAKING CAST MILL ROLLS 2 Sheets-Sheet 2 Filed Dec. 29, 1945 INVENTOR Frank Coraes Patented Mar. 28, 1,950

UNlTED STATES PATENT OFFICE MAKING CAST MILL ROLLS Frank Cordes, Pittsburgh, Pa.

Application December 29, 1945, Serial No. 637,845

2 Claims.

This invention relates to the manufacture of cast rolls, e. g., steel or iron rolls such as those used in rolling mills and, in particular, to rolls having a body including a plurality of cylindrical portions of various diameters.

The casting of high-quality mill rolls involves the exercise of a good deal of skill and experience in order to produce rolls which are tough and sound and have surfaces highly resistant to wear during use.

The demands of the rolling-mill art-are such that the roll maker is oftentimes called upon to produce a cast rollwhose body is of different diameters at difierent points along its length, as distinguished from the plain cylindrical roll body or barrel of uniform diameter from end to end. In making a roll with a body of varying diameter, it should be cast to a form approximating the desired configuration, that is to say, the roll as cast should ideally be of such configuration that the finishing of the cast roll in the roll lathe involves the removal of substantially the same thickness of metal from all of the surfaces, in the body portion, at least, of the casting.

The casting of such a roll body by present methods is not wholly satisfactory. The resulting roll may not be uniform in its physical characteristics, or may be otherwise of less than top quality metallurgically. Difficulties in moldin and casting are also encountered. Despite the existence of these shortcomings over a long span of years, the molding process has remained substantially unchanged.

My invention eliminates these difllculties and results in a cast roll of superior physical properties. My invention is also advantageous in that the manufacture of the rolls is simplified in many respects and the percentage of sound and satis factory castings is increased.

A complete understanding or the invention may be obtained from the following detailed description, referring to the accompanying drawings which illustrate somewhat diagrammatically a flask for use in casting rolls in accordance with my invention. In the drawings,

Figure l is a central vertical section through one form of mold for practicing the invention;

Figure 2 is a similar view of a modification.

Referring in detail to the drawings, I provide a flask ID for a sand mold having a cavity II corresponding in shape to the roll which it is desired to cast. It will be understood that the cavity is somewhat larger in all dimensions than shown at Ila in dot-and-dash lines, providing a substantially uniform thickness of surface material to be removed in the finishing operation. As shownin the drawings, the roll Ila to be cast in the cavity l I includes, in addition to the usual necks l2, spaced cylindrical body portions of vari-. ous diameters,-i. e., collar portions I3, I 4 and lb of one diameter and intermediate body portions or grooves l6 and ll of a smaller diameter.

The flask I0 comprises a plurality of superposed wall portions or sections of different diameters. A cylinder l8 resting on a base l9 has upper and lower flanges. The inside diameter of the cylinder 18 exceeds that of the portion of the cavity ll forming the lower neck 12 by a predetermined amount. A second cylinder 20 having upper and lower flanges rests on the upper flange of the cylinder I8 and is disposed coaxially therewith. The inside diameter of the cylinder it exceeds the diameter of the body portion l5 by the same predetermined amount aforementioned. A flanged cylinder 2! resting on the cylinder 26 also has an inside diameter exceeding that of the roll portion ll by said predetermined amount. The cylinder 2| is also disposed coaxially with the cylinders 20 and I8.

Similarly, cylinders 22, 23 and 24, when superposed coaxially on those already mentioned, together with a second cylinder l8 for the upper neck, complete the flask. The cylinder 23, as shown, is actually a solid ring of appropriate thickness but may be a flanged cylinder like that shown at 2 I.

The flask sections may be secured together in any convenient way, as, for example, by clamps 25 and wedges 26. In certain cases the sections may be divided longitudinally, as indicated by the unsectioned surface Me of the section 2|. It is thus possible to remove the flask portions when desired, either after complete cooling or when the casting has solidified but has not completely cooled, if metallurgical considerations demand such treatment. In the case of a deeply entrant section, such as the cylinder 23, it will be nec-- essary to make the same in parts or else to destroy it, in order to remove it from the casting.

The mold cavity may be formed by sweeping in the customary manner. on the other hand, all the cylinders may be divided along an axial plane and the cavity formed by the use of a pattern.

The mold may be bottom-poured in well known manner through an aperture 21 and is provided with the usual riser 28 at the top.

the desired finished roll, the outline of which is 56 The cylinders 20, 2!, 22, etc., constitute wall portions of the flask corresponding to the roll portionsli, l1 and M, respectively; the inside diameter of each wall portion exceeding the diameter of the corresponding roll portion by substantially the same amount. The axial length of the wall portion 20, furthermore, exceeds the axial length of the roll portion l5 by about twice said amount. The axial length of the wall portion 2|, however, is less than the axial length of the roll portion H by about twice said amount; Consequently, the thickness of the layer of molding material within the flask defining the cavity II is substantially the same both radially and longitudinally at all points. This means that, during cooling of the molten metal, the loss of heat from all points on the surface of the casting to adjacent points on the flask will occur at substantially the same rate, thereby effecting a substantially uniform cooling throughout the surface area of the roll. While the cylinders l8 forming the bottom and top of the flask as illustrated have the proper inside diameter to give the uniform thickness of molding sand adjacent tively low limits. At the same time, the cost of a flask according to the invention is comparable to that of a flask heretofore employed and presents no additional difllculties in use. It will be understood that cylindrical flask wall portions having dimensions appropriate to those of the roll portions generally cast may be made available and combined in various ways as may be necessary to produce a roll having body portions of the desired diameters.

Although I have illustrated and described but a. preferred embodiment of the invention, it will the roll necks, this is not so important as the uniform cooling of all portions of the roll body.

Figure 2 illustrates a mo'difled flask 30 which is split longitudinally and comprises a body 3| and ends 32 secured to the body. Instead of being composed of rings of various inside diameters according to the diameters of the roll portions l3 through I! as in the flask ill, the body 3| of flask 30 is composed of a cylindrical wall having rings 33 projecting inwardly therefrom adjacent the roll portions of smaller diameter. The rings 33 and the portions of the flask body therebetween constitute mold wall portions of different diam: eters corresponding to those afforded by the rings 20, II, 22, etc. of Figure 1.

The body and ends of flask 30 may be cast or fabricated. In either case, they may be provided with water jackets 34 and 35, in order to hasten the cooling of the roll cast therein. Pipe con nections 36 supply water to the jackets and it drains therefrom through outlet pipes 31. The jackets may be provided with longitudinal separator webs 38 to insure proper distribution of the cooling water around the flask body and ends. If the rings 33 are made hollow, holes 39 in the wall of the flask body permit entry of cooling water thereinto. If the flask is made by casting,

the rings 33 may be integral with the wall of the body portion.

It will be apparent'that a mold formed in flask 30 will have a wall of substantially uniform thickness at all points, despite variations in the diameter of the roll in different portions thereof.

The advantage of the invention has already been indicated, viz., the fact that the cooling of the roll as cast takes place at substantially the same rate at all points on the surface thereof. This makes it possible to control the metallurgical structure more precisely than heretofore and to avoid under-cooling at some points and overcooling at others.

In addition, the flask of my invention simplifles the problem of supporting the sand forming the mold, ,each flask section of smaller diameter carrying a portion of the vertical height of the sand layer. The flask also permits the mold recesses to be shaped to an accuracy within relahe recognized that changes in the details of the construction may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A mold for casting a ferrous rolling mill roll having a grooved body, comprising in combination, a metal flask, said flask having a plurality of cylindrical wall sections connected together coaxially, said wall sections being of different internal diameters and forming a substantially continuous metal internal surface the axial and radial configuration of which is generally similar to that of said grooved body, said internal surface being in direct metallic contact with the exteriors of said respective wall sections so that the ambient air contacting the said exteriors removes the heat conveyed by the metallic contact from said internal surface, and a layer of molding material such as sand covering said internal surface of said wall sections to substantially the same thickness, whereby substantially uniform cooling throughout the surface area of 83.1% grooved body is obtained when said roll is cas 2. A mold for casting a ferrous rolling mill roll having a grooved body, comprising in combination, a hollow cylindrical metal flask, a hollow annular ring axially spaced along the interior wall of said flask in each position corresponding to a circumferential groove in said roll and form- 'ingwith the remainder of said interior wall a continuous metal surface in direct metallic contact with a cooling fluid adapted to be circulated through said hollow flask and ring or rings, said metal surface substantially conforming in configuration to the configuration of the roll to be cast and uniformly larger than said configuration of said roll, and a layer of molding material such as sand covering each portion of said metal surface to a substantially even depth corresponding to the distance between said configurations, whereby substantially uniform cooling throughout the surface area of said roll is obtained when said roll is cast.

FRANK CORDES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 50,187 Totten Sept. 26, 1865. 843,679 Johns Feb. 12, 1907 990,710 Crook Apr. 25, 1911 2,104,906 Mueller et a1 Jan. 11, 1938 2,377,731 Walcher June 5, 1945

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