US1130911A

US1130911A - Hot mill-roll.

Info

Publication number: US1130911A
Application number: US84894714A
Authority: US
Inventors: Jacob Loomis
Original assignee: Individual
Current assignee: Individual
Priority date: 1914-07-03
Filing date: 1914-07-03
Publication date: 1915-03-09
Anticipated expiration: 1932-03-09

Description

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1,1 30,91 1 Patented Mar. 9, 1915.

,UNITED STATES ,PATENT oEEIoE.

JACOB LooIvIIs, oE WHEELING, wEs'I` VIRGINIA.

HOT MILL-ROLL.

Specification of Letters Patent. l

Application led July 31, 1912, Serial No. 712,396. Renewed July 3, 1914. Serial No. 848,947.

T0 all whom it may concern.'

Be it known that I, JACOB LooMIs, a citizen of the United States, residing at Wheeling, in the county of Ohio and State of West Virginia., have invented a new and useful Hot Mill-Roll, of which the following is a specification.

The object of my invention is to produce a roll which will have a longer average working life than those now commonly in use.

The accompanying drawings illustrate my improved roll in comparison with rolls of the type shown in my 1Batent No. 831,727, issued September 25, 1906.

Figure 1 is an axial section of a casting from which my roll may be machined; Fig. 2 is a section on line 2-2 of Fig. 1; Fig.l 8. a side elevation of the core around which was cast the casting shown in Fig. 1; and Fig. 4 a transverse section of a hollow roll after surface cracks have developed.

In the operation of hollow rolls in rolling mills, for the production of sheet metal, it is found that sooner or later very fine cracks will appear in the working faces. These fine cracksin many instances so fine as to be almost undiscernible by the unaided eyeproduce fineor coarser-hair marks or ridges in the sheets and thus make the product either uncommercial or low grade. These cracks in the rolls are, in general, substantially parallel with the axis of the roll and are most frequently first found in the region of the plane indicated by the corebox division mark left by the core around which the roll was cast. As is well known, these rolls are cast in molds having the axis of the roll (the core) vertical and the molten metal is introduced tangentially near the bottom of the mold. The main body of the mold contains a chill along that portion of its length which is to be the sheet-rolling portion, and the molten metal therefore cools more slowly adjacent the core. It is my opinion that, during this cooling, solidication (i. e., contraction) stresses are set up in the metal immediately adjacent the core which are tangential to the inner surface of the cast body and that those stresses result in minute cracks (or weaknesses tending to cracks) which extend lengthwise of the body substantially parallel with its axis and extend into the body in minute Vs which are substantially normal to the interior of the roll, asV indicated at 10, 10 in Fig. 4, on an exaggerated scale. There will be many of these minute cracks in substantially radial planes so that the roll may be analyzed as a barrel consisting of a plurality of associated staves.

lPatented Mar. 9, 1915.

Vhen this roll is used it is, of course, subjected to enormous pres- Y sures inv axial planes and therefore in substantial coincidence successively with the radial planes of the cracks 10. Ultimately the initial cracks l0 areextended into cracks 11 which lead to the working surfacev 12. This further cracking of the roll is, in my opinion, the result of the repeated coincidence of the crack-planes with the pressure plane and I have avoided the difliculty in the following manner. Instead of providing a core having a surface of revolution, as is the practice at present, I provide a core 13 having a surface composed of a plurality of adjacent helical ribs 14. The main body of the core may be of substantially uniform diameter but I prefer to continue the teachings of my Patent No. 831,727 and make the main body of the core of larger diameter at its middle, thus making each rib 14 a helix of decreasing radius at both ends. v

When the roll V15 (Figs. 1 and 2) is cas around such a core there will, of course, be formed adjacent helical channels 16 within the roll and, as a result of the cooling stresses,the minute cracks 10', which are unavoidably formed,rwill be normal to the surfaces of the. channels and, insteadV of lying in radial planes relative to the axis of the roll,w'ill be in helices. As a consequence, these cracks can never be brought into substantial coincidence withthe pressure plane but will always lie diagonally with relation to that plane and the rolling pressure will not tend to further extend the initial cracks.

I claim as my invention:

. 1. A roll having an axialchamber whose i surface is formed by adjacent helical channels of decreasing radii at both ends.

2. A roll having an axial chamber whose surface is formed by adjacent helical chan- 'y hollow, and. the nterrvlal surface comprising ginie, this 20th day of July, A. D. one thouinvvardly projecting integral ribs having a sand nine hundred and twelve.

general direction at an angle both to the axis of the rroll and a. plane at right angles JACOBLOOMIS [LS] thereto. 7Witnesses 'In witness whereof, I have hereuntoset WM. J. MURRAY,

my hand and seal at Wheeling, West Vir- Lome J. YAEGER.

Copies of this. patent may yhe obtained for five cents each, by addressing Commissioner of Patents,

Washington, 2D. C.