US 3550419 A
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Description (OCR text may contain errors)
Dec. 29, 1970 r A, FOX ET AL 3,550,419
METHODS AND APPARATUS FOR METAL ROLLING Filed March 4. 1968 v.-. v -l Fig.3.
United States Patent O 3,550,419 METHODS AND APPARATUS FOR METAL ROLLING Thomas A. Fox and Joseph Zentko, both Fox Industries, Inc., Box 358, Youngstown, Ohio 44401 Filed Mar. 4, 1968, Ser. No. 710,027 Int. Cl. B21b 11/00 U.S. Cl. 72-199 4 Claims ABSTRACT F THE DISCLOSURE A method and apparatus for metal rolling by introducing vibrational force into at least one roll outside the bearings.
This invention relates to methods and apparatus for metal rolling and particularly methods and apparatus for introducing vibrating force into the working rolls of a metal rolling mill to improve the rate of reduction and the quality of the product.
The art of rolling metals has been faced with the constant problem of increasing the speed and the quality of rolling. These two desired ends are frequently inconsistent and the industry has been continually beset with problems in its attempts to attain these ends.
We have discovered that we can improve both the speed and quality of the rolling by imparting a vibrating force into the mechanism of the rolling mill or roll forming line. We have found that when one or both of the Work rolls is vibrating, the work moves more freely and the resistance in the mill is reduced. This means that a greater reduction of metal can -be achieved by any given unit of force. The quality of the product is improved because of greater uniformity in thickness and a reduction in the strains induced by the mill.
We believe that the surprising effectiveness of our invention resides in an effect similar to that of forging combined with the rolling operation, thus with a prearranged frequency of vibration in a work roll, the metal being rolled is not only rolled in the conventional way, but is simultaneously hammered into itself. This we believe reduces the resistance and strain in both the mill and the work by reducing the pulling and stretching action of the mill required to produce a given reduction.
We have found that the manner of introduction of the vibrating force is important. We have found that the vibrating force cannot be introduced into the mill through the roll journals and bearings because the bearings are destroyed and the net efficiency is low. We have found that the vibration can be best introduced through the use of a roll of magnastrictive material operating in a pulsating magnetic field thus causing the roll to expand and contract as it rolls.
In a preferred embodiment of our invention we provide in a rolling mill having a housing, a plurality of rolls journaled for rotation in said housing, at least o'iie of said rolls being on each side of a pass line, and means for introducing vibrational force into at least one of said rolls outside the bearings to impart the sarne to a work piece in said pass line. Preferably, at least one of said rolls is formed at least in part of magnastrictive material operated in a pulsating magnetic field from a source adjacent the mill. In the practice of our invention it is preferred that the vibrational force be introduced in such manner as to cause successive rapid expansion and contraction of the roll as it rotates in contact with the work.
In the foregoing general description of our invention we have set out certain objects, purposes and advantages. Other objects, purposes and advantages will be apparent ICC from the following description and the accompanying drawings in which:
FIG. l is a front elevation of a two high mill embodying our invention;
FIG. 2 is a front elevation of a four high mill embodying our invention;
FIG. 3 is a front elevation of a second embodiment of a two high mill embodying the subject of our invention; and
FIG. 4 is an enlarged fragmentary view of a preferred form of roll and field inducing device.
Referring to the drawings we have illustrated in FIGS. 1 and 4 and a two high mill and roll therefore made up of a housing 10 of conventional design with rolls 11 and 12 on opposite sides of a strip 13 forming a pass line. Roll 11 is formed of magnastrictive material 14 surrounding a central shaft 15 carrying bearing journals 16 at each end. A hardened and ground alloy steel .sleeve 18 surrounds the magnastrictive material 14 and provides the actual working surface of the roll. An electrical coil 19 capable of providing a pulsating field is provided adjacent the roll 11. A frequency generator 20 or like electrical control is connected to coil 19 and provides the electrical power to operate said coil. The operation of the frequency generator causes a magnetic field of pulsating character to be produced by the coil 19. This in turn acts on the magnastrictive material 14 of the roll causing it to change its physical dimensions by enlarging and contracting on the diameter.
In FIG. 2, we have illustrated a second embodiment of our invention applied to a four high mill. Here a housing 30 of usual shape is provided with work rolls 31 and 32 on opposite sides of a pass line and back up rolls 33 and 34 on opposite sides of the work rolls. One of the back up rolls 33 is formed in precisely the same manner as roll 11 of FIG. l. Roll 33 is made up of a core 35 having journals 36 at each end. A magnastrictive material 37 surrounds the core 35 and an outer sleeve 3S. A magnetic coil 39 and frequency generator 40 are placed adjacent the roll 33 as in FIG. l.
In FIG. 3, we have illustrated a mill identical with that of FIG. l except that both work rolls are formed as shown in FIG. 4. The construction and operation of the mill is identical with that of FIG. 1 and like numerals with the prime sign are applied to like parts. The only difference between the mills is that both work rolls vibrate to work on the metal.
It will be obvious that in four high mills and the like, multihigh mills, all back up rolls, all work rolls, or one back up roll or one work roll might be vibrated to produce a desired result and these combinations are contemplated by this invention.
The principal working functions of this invention are believed to reside in our theory that when a magnetic field is placed with the magnetic lines of force penetrating a magnastrictive material, this material will expand and/or contract with the variance of this force, thereby when a frequency is passed through the coil a varying magnetic field will ensue in and about this coil, and since the magnastrictive material is in this field it will also be governed by the magnetic force, expanding and contracting in unison with this field, thereby when the magnastrictive material is in the core of the roll and a sleeve of suitable rolling material is placed on this core the sleeve will expand and contract due to the magnastrictive material forcing it to expand and its own elasticity will cause it to contract when the magnastrictive material contracts.
With the expansion and contraction of the magnastrictive material and the Sleeve material in unison, we have accomplished the desired effect of vibrating the rolls.
This method is unique in the fact that the roll itself is pulsating and does not put undue strain on the bearings or bushings causing deterioration. The amount of expansion can be governed by the magnetic flux and by the diameter of the core, since the magnastrictive material expands or contracts in one direction only and the amount of expansion and contraction is greater with the greater length along its magnetic axes.
Another form of increasing the length of expansion and contraction is by polarization of the material. This is done by applying a direct magnetic eld of suicicntly high intensity for the value of the magnetic eld to remain above zero.
Various other means for inducing vibration into the roll may be used such as by direct coupling of a transducer to the roll end. The important thing to be observed is that the vibrational energy be introduced to the roll through some means other than the bearings, i.e. outside the bearings and journals.
While We have illustrated and described certain preferred embodiments and practices of our invention in the foregoing specification, it will be understood that this invention may be otherwise embodied within the scope of the following claims.
1. In a metal rolling mill having a housing, a plurality of rolls journaled for rotation in said housing, at least one work roll being on each side of a pass line, and means for introducing vibrational force into at least one of said rolls within the body of the roll, said means expanding Cil and contracting the roll radially to apply periodic pressure perpendicular to the plane of said pass line.
2. A rolling mill as claimed in claim 1 wherein the said one of said rolls is formed at least in part by magnastrictive material providing a pulsating magnetic field.
3. A rolling mill as claimed in claim 1 wherein more than one work roll is vibrated.
4. The method of rolling comprising the steps of:
(a) passing a body of metal between two rolls under pressure, and
(b) subjecting at least one of said rolls to vibrational force introduced into the roll within the body of the roll expanding and contracting said roll radially to apply periodic pressure perpendicular to the plane of the pass line.
References Cited UNITED STATES PATENTS 2,995,050 8/1961 Karron et al. 72205 3,096,672 7/1963` Jones 72-247X 3,401,547 9/19618 Hall et al. 72-16 3,404,551 10/1968 Spisak 72F-l6 3,429,155 2/1969 Hines 72-16X FOREIGN PATENTS 133,324 10/1951 Sweden 29-VIBR MILTON S. MEHR, Primary Examiner