US1147713A - Metal-rolling. - Google Patents

Description

l. C. FOX. METAL ROLL|NG. APPLICATION FILED IuLY 24.1912.

A rounded corners, from larger sections com- JOHN c. rox, or WESTNONT BOROUGH, PENNSYLVANIA, AssrcrNon To GAMEEIA s'rEEL COMPANY, A CORPORATION. OE PENNSYLVANIA.

METALV-ROLLNG.

Specification of Letters Patent.

Patented muy at, reis.

Application flled J'uly 24, 1912. Serial No. 711,266.

To all whom it may concern.'

Be it known that I, JOHN C. Fox, a citizen of the United States, residing in the borough of lVestmont, in the county of Cambria and State of Pennsylvania, have invented certain new and useful Improvements in Metalj Rolling; and I do hereby declare the following to be a full, clear, and exact description of lthe invention, such as will enable others skilled inthe art to which it appertains to make and use the same.

My invention relates generally to metal rolling and more particularly to reducing and forming hot metal ingots, blooms, bil-- lets, bars or other shapes by a continuous process and apparatus whereby the said metalis operated upon successively by a series of rolls which are preferably placed with the grooves or passes thereof substantially in line, and so spaced as to operate on dierent parts of the metal at the same time.

Although my invention relates to any f shapes of metal, I will, for the sake of Isimplicity of description and ease of illustration,w confine these to the application of my invention in connection with rolling small billets, or approximately square bars with merciallyvknown as blooms, and in order to further simplify the description latein, lI will generally refer to the various sections as bars.

Heretofore in this art it has been thefgeneral belief that it suficed to overlook,- and consequently it kbecame the practice to neglect the finer and appropriate niceties ofl the design and to somewhat crud'ely proportion the rolling mill and the successive grooves or passes of the rolls thereof, so that. Y the amount of -material delivered from one pass to the next pass, andthe amount which is received and transmitted by said next pass, will be only approximately equal to each other. These amounts are dependent, among other things, upon the relative cross sectional areas of said passes and the speed ratios of the respective pairs of grooves in the rolls. This practice resulted ininequalities of operation, whereby, at times, considerably more material was delivered from one pass than from the succeeding pass, thereby causing an overfill and deformation of the material in the latter; or otherwise, more material was drawn by the succeeding pass from the preceding pass, thereby causgroove, but is considerably greater.

ing a tension in the bar between said passes and producing a wire-drawing action between successive pairs of rolls, in addition to the reducing action of the roll passes. By carefulstudy and experimentation I have discovered that rolls designed in this latter manner, that is, with a tension or drawing action betweenthe passes, may operate approximately correctly when the grooves of the various tandem continuous series of passes are filled with a bar extending through a number of said passes, but when the rear end of the bar issued from one of such passes, the tension and drawing action was at once relieved in that portion of the bar, thereby causing an overill, iin or deformation of saidbar in the next pass.`

My invention consists generally in the arrangement and proportiongof a series of con- -I have discovered that due and careful regard must be had to what I call the eifective diameter of the roll. By effective diameter `I mean that diameter passing through the axis of the roll at substantially right angles thereto, the ends of which diameter-travel at approximately Ythe same speed as the bar after it has issued from the forming pass, and at the same time when it has acquired regularity of longitudinal lmovement of translation given to it by frictional contact with the surfaces of the roll passes. As'explained herein, I have discovered that this effective diameter is not necessarily that diameter which correspondsv to the cylindrical surface of contact of the roll in the case of yan approximately flat, square or rectangular bar, butis a greater diameter,.and inthe' case of a diamondshaped bar this edec'tive diameter does not correspond with that of the bottom Of the Further details Aof this will hereinafter appear.

Having thus given a general description of my invention, I will now,in order to make the matter more clear, refer tothe accompanying sheet of drawings on which like characters of reference refer to like parts.

Figure 1 is a diagrammatic end elevation of a' series of twelve stands of two-high rolls, whichv operatev successively upon the bar as shown. Fig. 2 represents the series of passes or grooves formed in the rolls shown in Fig. 1, the grooves of each set being drawn as; cross sections directly below the rolls but 0n an enlarged scale, yso that their forms and proportions may be readily seen. Fig. 3 indicates approximately rectangular bars incorrectly rolled by previous methods, the first one having a fin and the succeeding one having a seam caused thereby.; while Fig. 4 represents bars of similar general shapes rolled by Amy improved method to proper proportions without fins, seams or deformations. Fig. 5 represents diamond and s'quare bars rolled by my method from the last passes Nos. 11 and 12,

'billet with which my rolling operation begins. rlhe pairs of rolls 5, 6, 7, 8, 9, 10, 11 and l2 are of smaller diameter and represent in the order of their numbers, the succession of pairs of rolls between which the bar passes continuously.

B represents the bloom or bar as it enters between the pair of rolls 1, and B represents the front end of the finished bar or billet as it issues from the last pair of rolls 12. y

Between rollsl and 2 a twisting arrangement is. used (not shown) in order to give the bar a quarter turn before entering the pair of rolls 2, and similar twisters are used between the pairs of rolls 3 and 4: and 5 and 6. These rolls 1 to 6 inclusive contain grooves known as box passes. After leaving the pass in the rolls 6, the bar is formed into what is known as anoval 'or diamond-shape in rolls 7, and between the airs of rolls 6 and 71 provide a twisting guide which gives the bar an eighth of a turn. Similar twisting guides provided with an eighth turn are arranged between rolls 7 and 8, 9 and 10 and 11 and 12, in order to quickly reduce the diamond or oval into the approximately square form as indicated. This arrangement of twists is shown to complete the illustration, but is not essential to my invention, as my method and apparatus can b' used with- Liet/,rie

out twisters in cases where preferable, as will be readily understood by those skilled in the art of metal rolling.

The cross sections of the roll passes, as li have designed them in accordance with my invention, are indicated successively as a1 to af,12 inclusive, in Fig. 2, and for convenience of reference each of these drawings is placed directly below the pair of rolls to which it applies. lt will be noted that approximately one-half of each pass is formed in the top roll and the other half is formed in the bottom roll with partin'gs, or slight distances betweenl the collars, adjoining the passes, all as indicated in Fig. 2.- The speed of longitudinal' movement of the bar increases step by step successively as it issues from each of the roll passes, the initial movement thereof being slow and the nal delivery being comparatively very rapid'. rlhe collars of the rolls or those portions adjoining the sides of the passes are indicated as g, g, g and the partings or diametral distances between said collars are indicated as e, e, e.

Referring now to the diiculties'heretofore mentioned in connection with improperly designed roll passes indicates a bar which would be formed, for example, in the pair of rolls 5 under these conditions, that is, with tension existing between the pair of rolls 4 and the pair of rolls 5. 'lihe reason for this is that as the bar travels in the direction of the arrow lbetween the rolls 4 and 5, thegrooves have been so designed in connection with the speed ratios of said rolls that a tension or pulling action exists in the bar between said pair of rolls, which reduces its diameter as it proceeds between them. When, however, the end of the bar passes outl from between the pair of rolls 4C, this tension and wire-drawing action no longer exists, so that the grooves in the rolls 5 receive more metal than they can properly form and reduce, with the result that the metal extrudes between the roll partings forming fins as indicated in f5. When the bar b is given a'quarter turn and rolled by the pair of rolls 6, these ns are pressed down into the body thereof and form seams or imperfections as indicated 'at s in the bar 56.

Section 511 in Fig. 6 represents a section of a bar produced in the pair of rolls 11 by an improper method due yto the fact that the rooves in the rolls 10 and 11 are so proportioned with respect to` their speed ratios, that a tension exists in the bar between the pair of rolls 10 and the pair of rolls 11, or in a previous pair, causing a iin f in the bar b for the same reasons as those previously mentioned. Similarly the seams S12 are formed in the succeeding bar Z212 which causes an imperfection in the finished product.y lin casera tension'eXists between the pair of rolls 11 and 12, the nsjfl2 will appear on thc last end of nished bar cl2, as it issues from the last pair of rolls 12, or in case this happens in connection 'with a fin such as f on the previous bar 511 ann f and a seam S12 will appear on the finished bar d, causing a double imperfection. On the other hand my rolls are designed in such a way that no appreciable or deforming ten-y sion can exist between the successive pairs of rolls such as between the pairs 4 and 5, so that when the bar issues from the pair of rolls 4, the same amount ofmaterial in the last end of the bar is furnished to the pair of rolls 5 as before. This being the case, there is no excess of metal delivered to the pair of rolls 5 and the operation proceeds properly and uniformly with the result of producing good sections such asa5 and ae. Similarly, I produce by means of my invention, sections such as an and a, free from the imperfections noted.

Although the foregoing is plain to those persons familiar with continuous metal rolling, in order to make this matter more clearly understood, it might be stated in approximately the form as follows'zLet D:

' the effective diameters of the roll passes,

, sumed as unity. Then,

that is, the diameter of the circle Ipassing through the cross section of said roll pass in a plane at right angles to the roll axes, the center o f one roll axis being the center of the said circle, the circumference of the circle passing through that point of the cross section of the bar which corresponds with its forward lineal velocity as given to it by the frictional contact of the bottom or the sides of the rolll `ass or a combination thereof, as may be. et 1c=the usual ratio of the circumference of a circle to its diameter, viz. :-3.14159|'. .Let A=the areas of the cross section of the bars formed in the pairs of rolls in question. Let R-:the speed ratios of the rolls, that is, the number of revolutions per. unit of time of an pair of rolls as compared with the rst pair, lwhich latter for convenience of calculation may be asin orderto properly desi the rolls in accordance with my invention, the product of D by 1c by A by R should, for each pair of rolls, be very slightly greater than that of the corresponding product for the succeeding pair of rolls, thus avoiding tension of the bar between the successive pairs of rolls, thereby obviating the consequent difficulties connected with said tension, as herein described.

The e'ective'diameter of the rolls varies considerably with the shape of the groove and somewhat with the heat or plasticity of the material passing therethrough. Generally speaking, however, I consider that the effective diameter of a box pass such asa?,- is the diameter of a circle located as heretofore described, the circumference of which passes through a point about one-fourth the distance from that surface of the bar which I is in frictional contact .with the surface of the roll, toward the center of the cross section ofthe bar. The effective diameter of the diamond or gothic square sections which are rolled diagonally, as vindicated in passes a7 toa12 inclusive, is that of a similar circle passing through a point about 7 0% or threei fourths the distance from the lower rounded corner of the-said bar and the center of said bar, and these are the figures which I prefer to use in proportioning rolls in the manner -heretofore described for the purposes mentioned in accordance with my invention.

To explain the matter in still another way, viz. :-One of the essential points on which my invention is based in order to prevent fins, seams and deformations in continuous rolling, is to deliver a very slight excess of material from one pass to the next, thereby preventing tension or drawing action. between one pass and the next. For example :-If there is tension between the pair of rolls 1 and the pair of rolls 2 then when the piece leaves the pair of rolls 1, this tension at once ceases and the pair of rolls 2 is overfilled, making a fin, which fin is rolled down in No. 3 rolls, causing a seam. Many attempts have been made to overcome this difficulty by rolling-mill men, but until my discovery and invention, these prior attempts have not been successful.

In practising my invention I may make rdetailed calculations showing the proportions between the various roll passes, the speed ratios and other elements thereof, to insure the absence of appreciable or deformaltory tension in the bar between the successive passes sufficient-to prevent the difficulties mentioned as inherent in prior practice, but as all these are subject to slight changes and variations within the scope of my 1nvention, any Vfurther details are considered unnecessary, and particularly so as the `descriptions herein will fully explain the matter to those skilled in this art. ,y Y Although I have shown and described my improvements in-considerable" detail, I do y not Wish to be limited tothe exact and speciic details shown and described, but may use such substitutions, modifications or equivalents thereof, as are embraced within the scope of my invention as pointed out in sists in simultaneously reducing a bar in a plurality of continuous alined passes, and in delivering a slight excess of bar material directly from one pass into the next, whereby an appreciable or deformatory tension is avoided in the bar between contiguous passes.

3. ln a metal rolling mill, a plurality of alined roll passes adapted to simultaneously reduce a bar passed therethrough, the cross sectional area of a preceding pass and the effective diameter of the same being so adjusted as to deliver in a given time a slight excess of material from said pass directly into the next succeeding pass, as compared with the amount of material delivered by said succeeding pass.

llc. lin a continuousrmetal rolling-mill of ritrarre the class described, a pair of alined roli passes adapted to simultaneously reduce a bar passed therethrough, the cross sectional areas and the eective diameters of said passes being so adjusted as to deliver a slight excess of bar material from one pass directly into the next pass in a given time, thus avoiding appreciable or Ideormatory tension of the bar between said passes, thereby preventing ins, seams or deformations in said bar.

In testimony whereof ll hereto ax my signature in the presence of two witnesses.

JOHN (l EUX.

WTitnesses el. F. GROGAN, Roer. A. Brenes.

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