US2083080A - Method and apparatus for rolling zinc and similar metals - Google Patents

Description

E. E. MILNER June 8, 1937.

METHOD AND APPARATUS FOR ROLLING ZINC AND SIMILAR METALS Filed June 18, 1955 2 Sheets-Sheet l June 8, 1937. MlLNER 2,083,080

METHOD AND APPARATUS FOR ROLLING ZINC AND SIMILAR METALS Filed June 18, 1935 2 Sheets-Sheet 2 INVENTOR Patented June 8, 1937- METHOD AND APPARATUS FOR BOILING ZINC AND SIMILAR METALS Edwin E. Milner, Muncie, ma, assignor to mu Brothers Company, a corporation of Indiana Application June 18,1935, Serial'No. 27,226

I 3 Claims.

This invention relates generally to the roll reducing of zinc and similar metals to sheet form and more particularlyto procedure and appa- -ratus for producing such metal in long strips,

which may be coiled and handled while in coil formation.

An object of the invention is to produce a new and improved process for rolling zinc and similar metals which avoids difllculties now encountered in connection with the commercial rolling of such metal.

'A further object is to produce a new and improved procedure and also a new and improved apparatus for rolling such metal into long thin lengths or strips, and for simultaneously preventing deformation of the strip or sheet as it is delivered from the reducing rolls.

A further object is toproduce improved apparatus for rolling slabs of zinc or similar metal into long lengths, wherein the several reductions necessary for producingvmaterial of the desired gage may be accomplished effectively and economically on a single stand of rolls.

These and other objects which will be made more apparent throughout the further description of this invention, are accomplished by means of the new and improved procedure herein defined, which may be carried forward by apparatus embodying features of, the apparatus illustrated in the accompanying drawings.

In the drawings, Figure 1 is a diagrammatic sectional view-of a new and improved roll stand and one which is capable of being-employed in carrying forward my new and improved process;

Fig. 2 is a diagrammatic sectional plan view, taken on the plane II-II of Fig. '1;

Fig. 3 is a plan view 'on a reducedscale of a I detail of apparatus illustrated in Figs; -1 and 2;

and

Fig. 4 is a plan view of apparatus which may be employed in carrying forward my improved process, and for convenience of illustration, the vari- V ous .pieces of apparatus are diagrammatically shown and the 'view is divided so that the lower Q portion thereof illustrates the delivery end of the,

tion of reducing the piece to the, desired gage.

55 The piece curves upwardly or downwardly as it;

(Cl. till-e51) issues from the rolls, with the result that it is far from flat and further operations on the sheet are rendered extremely difllcult because of the irregular shapes of the pieces issuing from the mill and also because of the lack of uniformity of 5 successive pieces as they issue from the mill.

Various attempts have been made to overcome this dimculty, which it is believed results from variation in the crystalline formation within a cast slab or piece. For example, various proce- 10 dures have been employed in the casting of zinc slahs in an attempt to obtain a uniform or homogeneous crystalline condition from end to end of the slab. .Various roll settings and various sizes and arrangements of rolls have also been 15 employed, but such known and devised expedients as have been tried in an attempt to overcome the difiiculty failed to produce even relatively flat pieces or pieces which could be readily and effectively handled in commercial operati ns.

The thought or realization that the dimculty encountered arose from a variation in the crystalline structure of the slab or piece finally resulted in the solution of the problem. It is well known that metal flows under the action of re- 25 ducing forces and that during such flow there is a rearrangement of the crystals and even a change in the crystalline structure as apiece of metal is subjected to the distorting forces imposed by reducing rolls. It was therefore con- 30 ceived that the application of straightening forces to the piece as it, issued from the rolls would be effective provided the forces were so applied 'as to be effective at the point where the reducing forces occasioned relative movement between the grains- 35 or crystals of the metal. In other words, it was conceived that corrective forces applied to the metal while the grains or crystals thereof were undergoing a rearrangement in response to'the reducing forces, would overcome the difficulty. 40

This theory led to the solution of the problem and a principal feature of my new procedure is to apply corrective forces to the metal at the time its crystalline structure is in unstable equilibrium or is responding to the reducing forces applied thereto.

. .Onearrangement of drawings; There the arrangement ofapparatus is such that each length element of the piece of .metal being rolled is so confined as it issues from the reducing rolls that'irregularlties in the shape 1 of thefpiece' are substantially prevented.

other. words, the arrangement :orapparatus :is'

such that any tendency to cobble is immediately .5

pp aratus for applying} this rinciple is disclosed in Figs. ,1 and 2 of the overcome. The effect of this apparatus, is, however, more far reaching than this because the corrective forces are applied, through the rolled piece itself, at a point where the distorting ef- 5 fect of the rolls is occasioning a flow of the metal and a rearrangement of theorystalline or grain structure thereof.

The rolling mill 6, diagrammatically illustrated in Figs. 1 and 2, consists of a stand having opposed reducing rolls 1 and 8. These rolls may be of unequal diameter or they may be, as shown. of equal diameter. Each roll is a driven roll and the drive for the rolls is such that the A peripheral speeds of the two rolls are substantially equal. The slab or piece entering the active pass between the rolls is positioned and guided by side guides 9 and I 0, with the result that each piece is delivered to the opposed reducing rolls at a point intermediate their ends and so that the longitudinal axis of the piece is located approximately midway between the neck bearings of each roll.

At least one of the rolls is adjustable toward and away from the other roll in order to vary the thickness of the pass, i. e., the distance be.-

' tween the cooperating surfaces of the rolls. For example, the bearings of the upper roll I may be vertically adjustable and, under such conditions, the bearings of the. lower roll 8 may be stationary. The adjustment of the roll 'I may be accomplished by means of ordinary screw downs so that the thickness of the pass, 1. e., the distance between the rolls 1 and 8 may be varied, thus providing for variations in the thickness 36 of the pieces rolled and variations in the amount of reducing pressure applied by therolls, all as is usual procedure in rolling mill operations.

- In this connection it will be understoodathat the mill 6 may be of the usual form of the modem 40 reducing mill. It may be a two-high as illustrated, or it may be a backed up mill, such as a four-high or a cluster mill. operation of reducing the piece may .be carried forward on two or more mills, thus accomplishing the reduction of each piece on several rather than one mill and obviating the necessity for employing apparatus for returning each piece to the single-stand or mill as contemplated in connection with the apparatus illustrated. Economy of first cost or in capital expense, however, indicates the desirability of employing a single mill, 1.. e., a single standof rolls, and conse-' quently the drawings illustrate the now preferred apparatus for carrying forward my improved 55 process.

I In the apparatus illustrated, the mill is provided with a corrective device located on the delivery side and in cooperative relation with the rolls thereof For descriptive purposes this de- 80 vice may be termed a straightening device, al-

though it will be apparent that its. function is not that of an ordinary straightening device, since it so applies corrective forces to the piece as it is rolled so as to avoid the necessity for straightening the piece after the. rolling operation. As.

illustrated in the diagrammatic views of the drawings, this device consists of jaws II and I2,

which project into the crotch between the rolls and to a point adjacent to the elective or active pass between the rolls;

Each jaw is so formed and so positioned that it, in effect, forms a continuation of the peripheral face of the'roll with which it and against which it is yieldingly held. For this rea- !5 son, each jaw is wedge shaped, terminating in In' addition, the

a knife edge or an approximation of a knife edge and is pivotally mounted on an adjustable carriage, l3. In the illustrated embodiment, each carriage I3 is provided with a series of rolls which act to guide the piece as it exits from the rolls I and,8 or fromthe jaws and Hand, as shown in Fig. 2, each carriage is adjustable toward and away from the other and may be clamped in an adjusted position by means of a T-head bolt and nut assembly I 4, wherein the T of the bolt is located in a vertical way formed in the frame of the mill. Each jaw (II or I2) is provided with two operating lugs l5, and each such lug is pivotally connected to a separate link l6 which acts, through the agency of a coil spring I 1 and an adjustable nut l8 carried 'by the link, to hold the knife edge of the jaw in contact with its corresponding reducing roll (I or 8). As shown, each link extends through an aperture formed in a flange l9 of its carriage and the coil spring I1 surrounds the link and acts between the associated adjusting nut I8 and the flange l9.

It will also be apparent that the inner face of each jaw while, in effect, forming a continuation of the peripheral face of its cooperating reducing 'roll, acts as a guide for the piece leaving the roll pass,'and that the opposed faces of the jaws provide a restricted passage through which the piece issuing from the rolls, must pass. Any tendency for the piece to cobble, by either turning up or down as it issues from the pass, is resistedby one or the other of the jaws II and I2. Under such conditions, each length element of the piece is subjected to a corrective action at the instant of its reduction, and this even though the jaws do not extend clear into the active pass, since the portion of the piece intervening between the active portion of the pass and the jaw acts to impart the corrective force,

imparted by one or the other of the jaws, to the portion of the piece, wherein the reduction is taking place and wherein the crystals or grains of the piece are undergoing rearrangement by reason of the reducing forces acting on them.

As previously noted, each carriage I3 is provided with directing rolls 2|. As shown in Figs.

2 and 3, these rolls are arranged in two sets and the rolls of one set are located in staggered relation with the rolls of the other set. Rollers 22 are mounted on the fulcrum pin 23 of each jaw and theserollers, together with the rollers II, in effect, form anti-friction surfaces over which the piece passes as it issues from the rolls.

One of the features of my invention is that the corrective or straightening device more or less automatically adjusts itself to the variations in the roll positions which are made for the purpose of varying the width of the pass and the degree of roll press on the piece traversing the pass. This is occasioned by the fact that each jaw is pivotally' mounted and is yieldingly held against the peripheral surface of one roll. However, as stated, the jaw carrying carriages may be adjusted vertically, thus providing a relatively wide passage forthe material issuing from the mill during the earlier or initial reductions of a slab or piece and also making it possible to decrease the vertical width of this passage as the reducing rolls I and I are moved closer together in the later passes through the mill. This adjustability of the carriages II and jaws (II and I 2) also enables the operator to control the degree of straightness of the pieces issuing from the mill.

As shown in Fig. 4, the mill constitutes a part of an organized apparatus including a roller table 24 located on the entrance side of the mill and adapted to deliver slabs and pieces to the 5 mill. A roller table 25 is located on the exit side of the mill and receives the pieces as they issue from the mill and consequently as they issuefrom the corrective or straightening device. The rollers of this table .are inclined so as to direct the pieces traversing them toward one edge of the table or toward the lower edge of the table in the illustration. A transfer device 25, which may be in the form of a plurality of suitably equipped and driven conveyor chains, is associated with the roller table 24 and is adapted to transfer the rolled pieces from that table to a table 21, which extends parallel to the tables 24 and 25 and is adapted to move pieces received from the transfer device 26 in the reverse direction or backtoward the receiving end of the associated apparatus. A second transfer device 28, which may be in the form of a wide table, is located between the table 21 and the table 24, and its function is to deliver pieces from the table 21 to the table 24 preparatory to sending each such piece again through the mill 6.

The operation of the apparatus is as follows:

A slab or piece to be roll reduced is delivered from a furnace or in heated condition to the conveyor or roll table 24. The rolls of this table are actuated to deliver such piece to the mill 5., It will, of course, be understood that the rolls of the mill are previously adjusted in accordance with the thickness of the piece and the 30 amount of reduction to be accomplished by the first pass of the piece through the, mill. The piece is guided duringits entrance into the pass by the guides l0 and the rolls 1 and 8 of the mill are driven at an appropriate and desired speed. As each length element of the piece traverses the pass, it is reduced in thickness and increased in length and consequently issues from the rolls and between the jaws I l and I2 reduced in thickness an amount depending upon the setting of the rolls.

Any tendency of the piece to cobble, i. e., turn either up or down, is prevented by the jaws and each length element of the piece is sufficiently stiff, at the timeit reaches the jaws, that it acts in transmitting the corrective force applied to it by the jaws to the portion of the piece within the active pass between the rolls, or the portion of the piece wherein the crystals or grain structure are moving in response to the reduced forces applied by the rollsTand are thus in unstable equilibrium. It is, therefore, apparent that the re-adjustment of the crystalline structure of each length element of the piece is accomplished while that length element is under the influence of the corrective forces occasioned by the corrective device or the jaws H and I2.

The carriage l3 associated with each jaw also aids its associated jaw in applying corrective forces to the piece. For example, it may be that 65 the tendency of the piece to cobble is not great enough to throw the piece in contact with either of the jaws II or l2, but is of sufficient magnitude to cause the piece to contact with either the upper or the lower carriage l3. Under such conditions the carriage resists the tendency and the intervening portion of the piece between the carriage and the pass transmits the corrective force to the portion of the piece responding to the action of the rolls 1 and 8. The piece as it issues from the space between the carriages I3 is received by the roller table 25. As previously described, the rolls of this table are inclined. It

is therefore desirable to arrange the rollers 2! of the lower carriage so that they conform to the inclination of the adjacent rolls of the conveyor 25. The piece issuing from the mill is propelled along the table 25 by the propelling force of the rolls 1 and 8 and the propelling force of the rolls ,of the table 25. As the piece moves out of the It will, of course, be understood that the rolls of the mill are re-adjusted between each such passage of a piece and that two or more slabs or pieces may be rolled in succession before a previously rolled piece, is returned to the mill for additional reduction.

As the rolls 1 and 8 of the mill are moved toward each other during the successive reductions of each piece, the jaws II and I2 are readjusted, by reason of the re-positioning of the rolls and, as stated, the carriages l3 may also be re-positioned, although in ordinary operations it is only necessary to re-position the upper carriage, since, as above described, the upper roll only of the mill 5 is adjustable.

Thus it will be apparent that each length element of each piece traversing the mill 6 is subjected to corrective forces at the time it is subjected to the reducing forces transmitted by the rolls 1 and 8. As a result, each piece is relatively flat as it issues from the mill and the successive pieces are substantially uniform from the standpoint of degree of flatness.

It will, of course, be understood that each piece is reduced in thickness and increased in length each time it moves through the mill 6 and that when reduced to final gage, it may be coiled as it issues from the mill or as it leaves the roller table 25.

While I have illustrated and described but one form of apparatus for carrying out my invention, it will be apparent that my new and improved process may be carried forward by means other than the apparatus illustrated, and that various changes, both in the apparatus illustrated and in the mode of procedure outlined, may be made without departing from the spirit and scope of my invention as defined by the appended claims.

What I claim as new and desire to secure by Lctters'Patent is:

1. Apparatus for roll reducing zinc comprising a pair of opposed reducing rolls, a roller table located on the entrance side of said reducing rolls, means associated with said table for directing a piece into thepass between said rolls, and means for applying a corrective and rearranging force to the crystals of the piece being acted upon by said reducing rolls including opposed vertically spaced jaws at the delivery side of said rolls and extending into the crotch between said rolls into contact with the peripheral face of one such roll, each of said jaws having a directing surface formed thereon substantially parallel to thepass line between said reducing rolls for engaging the piece emerging from said roll whereby the length of the piece between said jaws and said reducing rolls is utilized to transmit the corrective force from said jaws to the portion of the piece within the active pass of said rolls.

2. Apparatus for roll reducing zinc comprising a pair of opposed reducing rolls, means for directing a piece into the pass between said rolls and means at the delivery side of said rolls for applying a corrective force to the crystalline structure of said piece undergoing rearrangement between said reducing rolls including opposed carriages at the delivery side of said rolls, one of said carriages being vertically adjustable, a jaw pivotally mounted on each of said carriages and extending into the crotch between said rolls into contact with the periphery of one such roll, said jaws being vertically spaced and arranged in substantially parallel relation to each other, means for yieldably holding said jaws in contact with the peripheral face of one said roll, and a series of guide rolls on each of said carriages adjacent the rear ends of said jaws for delivering the corrected piece from the reducing rolls.

3. Apparatus for roll reducing zinc comprising a pair of opposed reducing rolls, means for directing a piece into the pass between said rolls, and means for applying a corrective force to the crystalline structure of said piece undergoing rearrangement by the reducing rolls, including opposed vertically spaced carriages at the delivery side of said rolls, each of said carriages being vertically adjustable, a jaw pivotally mounted on each of said carriages and extending into the crotch between said rolls into contact with the peripheral face of one such roll, said jaws being vertically spaced and each having a directing surface substantially parallel with the pass line between said reducing rolls for engaging the piece emerging from said rolls and transmitting the corrective force to that portion of the piece within the active pass of said rolls, a series of rollers on each of said carriages adjacent the rear ends of said jaws and means for yieldably holding each of said jaws in contact with the periphery of one of said rolls.

EDWIN E. MILN'ER.

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