US2428301A - Method of producing forming rolls for use in rolling mills and the like - Google Patents

Description

V. M. SURERUS Sept. 30, 1947.

METHOD OF PRODUCING FORMING ROLLS FOR USE IN ROLLING KILLS AND THE LIKE Original Filed Kay 24, 1944 3 Sheets-Sheet 1 INVENTOR. VLCZOI'MJLUEI'ZLZ Sept. 30, 1947. v. M. SURERUS 2,428,301

METHOD OF PRODUCING FORMING ROLLS yon USE IN ROLLING MILLS AND THE LIKE Original Filed May 24, 1944 3 Sheets-Sheet 2 I VVEN TOR.

2rd; W 2? Patented Sept. 30, 1947 METHOD OF PRODUCING FORMING ROLLS FOR USE IN ROLLING MILLS AND THE LIKE Victor M. Surerus, Chicago, 111., assignor to Inland Steel Company, Chicago, Ill., a corporation of Delaware Original application May 24, 1944, Serial No. 537,124. Divided and this application March 19, 1945, Serial No. 583,526

Clalms. 1

This invention relates to the process hereinafter disclosed by which novel forming rolls of the type employed in rolling mills may be produced.

This invention is a division of applicant's copending application SerialNo. 537,124, filed May 24, 1944.

The forming rolls of this invention are particularly adapted to impart the final or finished shape to metal bars, such as reinforcing bars and the like. In applicants continuation-impart application Serial No. 537,125, filed May 24, 1944, now Patent No. 2,377,980, issued June 12, 1945, and its parent application Serial No. 501,553, filed September 8, 1943, there is disclosed and claimed a new and improved reinforcing bar for concrete, which has a generally round cross-sectional shape and is provided with oppositely disposed sets of lugs with the lugs on one side inclined in one direction and the lugs 0n the opposite side inclined in a reverse direction. The reinforcing bar of the construction referred to is extremely advantageous in use as a reinforcing bar but its production by commercial methods, such as by rolling operations, has presented various inherent difilculties which have prevented its manufacture until the rolls and the process of producing them, constituting this invention, had been conceived and reduced to practice.

It is an object of this invention to produce improved pairs or stands of finishing rolls of the type referred to for forming bars, such as reinforcing bars, having oppositely disposed sets of inclined or spirally arranged lugs which extend substantially throughout 180" of the circumference of the bar, and particularly to provide a, new and improved method by which such rolls may be made.

A still further object is that of producing highly eflicient rolls which may be manufactured and maintained at relatively low cost and which are useful in producing the new and improved reinforcing bar referred to.

Inasmuch as the bars of the type referred to include in their construction lugs which extend substantially entirely around the bar and which at the same time are disposed at an angle to the longitudinal axis of the bar, difliculty was encountered in providing forming rolls of character and shape that would satisfactorily produce such bars by the usual type of rolling operation.

To form a-bar of this type, the forming rolls must have deep, substantially semicircular grooves extending circumferentially thereof, and, in addition. angularly disposed lug-forming grooves formed in the metal at the sides and base of the semicircular grooves, which latter grooves must also extend throughout the major portion of 0! the entire circumference. The requirements of the rolls so constructed are such that they cannot be formed by any practical commercial method herefore employed for producing such rolls, wherefore it was not until the applicant had succeeded in applying the present novel procedure and had conceived and constructed the novel rolls of this invention that commercial production was possible.

One of the difficulties which had to be met in constructing the rolls, resides in the fact that the character of the bar and of the forming rolls is such that a particular structural relationship must be provided between the rolls and the bar in order to permit the forming rolls, during the bar-forming operations, to free themselves of the bar without wiping or destroying the lug formation on the bar after the lugs have been formed. This problem was made more acute by the fact that such freeing of the roll and bar requires that the forming portions of the roll which move in an are are in engagement with lugs which are moving in a straight line and, in addition, are being subjected at the same time to a drawing or elongating operation which is productive of a variation in the linear velocity of the bar leaving the rolls with respect to the angular velocity of the forming rolls. The solution of this problem involves an understanding of the action which takes place, and it has been found that there is a limit as to the height of the lugs that can be utilized on bars of any given diameter and, in addition, that the angularity of the leading side of each of the lugs in relation to the pass-diameter of the forming rolls (hereinafter defined) and the height of the lug being formed are also limited.

Another problem which has been met by the invention of applicant's copending application referred to, is that presented by the existence of twisting components that are developed during the rolling operation by the forming contact between the angularly disposed faces on the rolls and corresponding faces on the lugs, which forces tend to produce a twisted and distorted bar if the force is not adequately offset. In one form of the present invention the rolls are constructed so that the opposite sets of 11185 on the bars are oppositely disposed as to angularity, whereby the twisting forces so exerted act to offset each other, with the result that a satisfactory straight bar is produced without undue strain or wear on the rolls.

Another object of this invention is to produce mitted to escape during the rolling operation so as to eliminate spelling and consequent damage to the rolls and bars being rolled.

A further object of this invention is to produce rolls of the type referred to, by first forming the desired number of circumferential pass grooves extending around the rolls, and thereafter producing a series of spirally disposed lugforming grooves in the pass groove or grooves to be utilized by means of a tangentially disposed rotary tool or hob placed in the pass groove and on which there is provided a plurality of spirally disposed groove-cutting elements, and thereby forming the grooves by causing the hob and the roll to rotate at the proper relative speeds.

It is a further object of this invention to form one roll of each pair by means of a hobbing toolof the type referred to, having the cutting elements disposed on a spiral of one hand and forming the other roll of the pair by the use of a hobbing tool having cutting elements of the opposite hand, and in this manner to form a pair of rolls to form lugs developing opposed or ofisetting twisting components of force during the rolling operation.

It is a further object of this invention to produce rolls of the type referred to, which have 30 lug-forming grooves of such construction as to their depth and as to the angularity of their leading side that they will form the lugs as desired and at the same time pass freely from the lugs without wiping or in anywise damaging the lugs so formed.

It is a further object of this invention to produce rolls which are free from sharp corners or edges, whereby they are capable of long life without suffering unusual damage or undue wear, and which, by means of the hobbing tools, may be produced by a highly practical and inexpensive procedure.

These and other objects not specifically enumerated are contemplated for this invention, as will readily appear to one skilled in this art as the following description proceeds. In the following description of one illustrative embodiment of the invention, reference will be made to the accompany drawings, in which- Figure l is a side elevational view of a pair of rolls constructed in accordance with this invention.

Figure 2 is a cross-sectional view showing the rolls and an associated bar being processed 5 thereby.

Figure 3 is an elevational view showing one of the rolls in the process of manufacture.

Figure 4 is a plan view of the roll and the associated hob illustrated in Figure 3.

Figure 5 is a fragmentary view of a section of the bar produced by the rolls of this invention.

Figure 6 is a view similar to Figure 5 but showing the bar after the bar has been rotated 90' on its axis.

Figure 7 is a cross-sectional view taken on the line 1-! of Figure Sand looking in the direction of the arrows.

Figure 8 is a view similar to Figure 6 showing a bar of slightly different construction, in that the 70 sets of lugs on opposite sides of the bar have their ends out of alignment.

Figure 9 is a cross-sectional view taken on the line 9-9 of Figure 8 and looking in the direc- 'tion of the arrows.

Figure 10 is an enlarged, fragmentary. crosssectional view showing the construction of one of the lugs of a. bar produced by the rolls of this invention; and

Figure 11 is an enlarged, fragmentary, perspective view, partly in cross-section, showing one of the lug-forming grooves of the rolls of this invention. By referring to the drawings, it will be noted that the rolls produced according to the present invention are illustrated as embodied in a twohigh rolling mill comprising uprights Ill-l0 of a roll stand and a pair of rolls II and I2, respectively, iournaled in the uprights and driven by any suitable means (not shown).

The rolls H and I2 are each provided with a series of circumferential pass grooves I3 which are so disposed on the rolls, respectively, that each of the grooves of upper roll ll cooperates with corresponding grooves on the lower roll 82,

0 whereby a series of bar-forming pass openings are provided between the rolls. The rolls are maintained in spaced relation, as indicated at I 4, so as to provide a space on opposite sides of each of the grooves l3 to accommodate the metal of the bar which is extruded laterally during the rolling operation so as to form a pair of diametrically disposed, longitudinally extending ribs on the bars.

Each of the grooves of the upper roll H is provided with a series of equally spaced lugforming grooves l5 which are cut on a spiral path into the side and base metal of the groove. Similar lug-forming grooves I5 are provided on the lower roll l2, but in the form of the invention illustrated in Figure 1, the grooves 15 are spiraled in the opposite direction. Although lug-forming grooves are illustrated in Figure 1 in only one of the sets of pass grooves [3, it is to be understood that each of the sets to be employed 0 for bar-rolling operations is to be similarly constructed.

The pass grooves I3 may be formed in the rolls by any conventional method by the use of suitable mechanism, and after the rolls are so grooved they may be further processed in the manner illustrated in Figures 3 and 4.

From these figures of the drawings it will be noted that a turntable may be utilized, having centrally mounted thereon a chuck 2| provided with centering holding screws 22-22 for engagement with the depending bearing portion of the roll. The roll is thus centrally mounted and is adapted to be rotated with the turntable on the central axis of the roll.

The lug-forming grooves are next formed by means of a hob 25 which, as shown in Figure 4, is mounted for tangential engagement with the roll at the location of the groove l3 being processed. The hob is preferably constructed as shown in Figure 4, that is to say, it is provided with a plurality of cutting elements 2-6 projecting radially therefrom and arranged toexert their cutiing effect in a spiral path. The hob in this form is mounted in suitable means (not shown) for rotating the same and at the same time advancing the hob bodily toward the axis of the roll being cut.

If exact specifications are to be maintained as to the pitch of the lugs on the bar to be formed, consideration must be given to the elongation of the bar which is effected during the rolling operation, in relation to the inherent shrinkage of the metal of the bar during the cooling thereof. In those instances where the draft is sumcient to cause the elongation of the bar to be greater than the shrinkage, then the pitch of the lug-forming grooves on the rolls must be made correspondingly smaller. The hob is so constructed that a predetermined number of lug-forming grooves will be cut in the pass groove l3 of the roll, with the correct spacing between each of the lugiorming grooves so cut, whereby the action of the hob can be carried out while the roll is being rotated a plurality of times to the extent necessary to finish the cutting operation.

If desired, the turntable 20 and the hob can be independently driven, provided suitable synchronizing mechanism is utilized to maintain the rotation of each in-proper relationship. On the other hand. in those instances where the drivin force is not too great, the turntable may be left free to derive its rotary motion through the driving action imparted by the hob during the cutting operation. Flu'thermore, means must be provided, either manual or otherwise, for advancing the hob bodily toward the axis of the roll, whereby the depth of the lug-forming grooves will be increased as the cutting action progresses.

In malclng one roll of a pair of rolls, such as the upper roll H, for instance, a hob 25 is employed which has its cutting elements disposed on a spiral of one hand involving a rotation of the roll during the cutting action in the corresponding direction. In cutting the other roll, however, a hob having its cutting elements arranged in a spiral of the other hand will be utilized, which will involve the rotation of the roll in the opposite direction. Instead of rotating the roll in the opposite direction, of course, the hob could be rotated in the opposite direction from that employed in cutting the first roll, but it is preferable in both instances to rotate the hob so that its cutting elements pass downwardly during the cutting stroke, so as to force all of the metal chips downwardly and out of the path of the cutting elements. The direction referred to may be described as clockwise in the illustration of Figure 3.

Referring now to Figure 11, it will be particularly noted that the lug-forming grooves in the roll are provided with inclined lug-forming side faces 3| which preferably terminate in a rounded fillet-forming surface 32 at the location of the base of the lug. Inasmuch as the angularity of the side of the lug is limited as to its steepness or its approach to the vertical in instances where wiping or unwanted damage is to be avoided, the maximum angle that can be employed is represented in the drawings as the angle G, which is the angle of the inclined surface with respect to the vertical. This angle is marked on the lug in Figure 10 and on the groove in Figure 11.

It has been found that for a bar of any given diameter it is desirable to limit the height of the lug for any given angularity of the lug in order to avoid wiping and damage during the rolling operation. The applicant has devised a formula for determining the height of the lug, which formula is as follows:

Lug height B==(.0464Xnominal d ameter of bar)+.0'1) inches in which the nominal diameter of bar is the diameter of the plain round equivalent in weight of the nominal size bar.

Example for 1% inch nominal size 1 inch square nominal size== 1.410 inch diameter equivalent round wherefore Lug height B=(.0464 1.410)+.020

or .065+.020, or .085 inch.

6. In addition, the applicant has worked out a formula by which to determine angle G in my particular case, which formula is as follows:

Angle G=angle R-angle S wherein angle R=the angle whose tangent is equal to .ers 10BX4/Pss" 5 dia.)

and

Angle S=an angle of degrees and in which B==the height of the lug and Pass diameter=the outside diameter of the rolls minus twice the depth of pass (depth of the pass groove).

Example for 1% inch square nominal size Pass dia.=l4.986-(2 .641)

or 14.986-1282, or 13.704 inches.

Height of lug=.085 inch (see example above) Angle R=the angle whose tangent is equal to Angle S 085 degrees or l.176 or 1 11'.

Angle G=angle Rangle S In utilizing the above formulas, the height of the lug is the maximum permissible, whereby lugs of the height determined by the formula, as well as lugs of less height, may be employed without suffering wiping or damage.

Similarly, in. utilizing the formula for angle G, it is important to know that angles less than those determined by the formula cannot be used without suffering wiping or damage, wherefore it follows that angles greater than those determined by the formula may be employed. These formulas are correct and workable for bars of different sizes and can be employed in rolling all sizes required for a full commercial range, varying from the smallest sizes around inch up to 1 inches, and larger.

In considering the significance of angle G, it should be understood that the limitation imposed thereby is applicable only to the lead angle of the lug on the bar for the reason that during the rolling operation the advancing movement of the bar when leaving the rolls tends to overtake the lug-forming portions of the rolls, and hence the angularity of the cooperating portion of the roll and lug must be such as to permit a free passage if wiping and damage are to be avoided. By the "lead angle the front or advancing face of the lug is referred to. On this account, the rear or trailing faces of the lugs on the bar may be of any desired angle. In the present illustration, the trailing faces of the lugs have the same angularity as the leading faces for the purpose of uniformity in both directions, but such is not essential to this invention.

Referring now to Figures 5 to 10, inclusive, it will be noted that the bar produced by the rolls of this invention comprises a solid, substantially cylindrical body or core section 40 provided with diametrically opposed parallel ribs 4|, 41 extending longitudinally of the bar, as well as diametrically opposed sets of spirally disposed lugs 48, 44 located between the ribs 4| and 42 and joining the same at their ends. The lugs 43 and 44 are each segments of a spiral, and one set is a segment of a right-hand spiral and the other set a segment of a left-hand spiral, whereby the adjacent ends of the lugs of the two sets, which terminate at the locations of the ribs 4| and 42, are inclined in opposite directions with respect to a plane normal to the axis of the bar. Thus viewing the bar as in Figure 6, the spirally disposed lugs 43 and 44 converge from the left-hand end toward the right-hand end of the bar as shown, whereas when the bar is rotated through 180 the lugs will converge in the opposite direction.

The lugs 43 and 44 have inclined faces as'determined by angle G (see Figures and 11) or any angle greater than angle G, and at their bases are provided with concaved fillets, as shown at F in Figure 10. Similar fillets, shown at 4B, are provided at the base of the longitudinally extending parallel ribs 4| and 42 so as to eliminate sharp corners or pockets.

It is apparent that bars of this construction will be produced when stock of suitable configuration is passed through a mill such as that shown in Figure 1 and the rolls are constructed in the manner described above. In rolling the bar, it is preferable to effect approximately a reduction in the finishing pass of the rolling operation, which not only causes the lugs to be formed as indicated but also the rigs 4| and 42 to be extruded laterally into the space between the mils. This operation results in the bar having ribs 4| and 42 of substantially the same height as the lugs themselves. When the lugs are inclined in opposite spirals, as above indicated, all tendency toward twisting of the bar is eliminated during the rolling operation and a satisfactory straight product is produced. Furthermore, due to the rolling action, the final pitch of the lugs on the finished bar will be greater than the pitch of the lugforming grooves provided in the forming rolls.

While the invention is not limited to rolls productive of bars having any specific dimensions of the core, lugs, or ribs, other than as hereinabove indicated by the formula. when wiping is to be avoided, the following specifications and proportions as to certain sizes of ribs are here given merely by way of example, which when followed will provide satisfactory reinforcing bars or light, medium, and heavy weights, respectively, that is to say, bars having the same weight per foot, namely, .376 pound as a plain round inch diameter bar; bars having the same weight per foot, namely, 2.44 pounds as a plain round V3 inch diameter bar; and bars having the same weight per foot, namely, 5.313 pounds as a 1 /4 inch square diameter bar.

In accordance with the above example of the lighter weight bar, the core is .354 of an inch diameter; the depth, indicated at B, of the depressions framed by the ribs and lugs, .038 of an inch; the width, indicated at C. of the ribs at their circumferential surfaces .040 of an inch; the width, indicated at D, of the lugs at their circumferential surfaces, .031 of an inch; the pitch, indicated at E, .203 of an inch; the radius, indicated at F, of the lug fillets, ,52 of an inch; and the radius indicated at F of the rib fillets, ris of an inch.

In the case of the above example of a medium weight bar, the core 40 is .825 of an inch diame- 8 ter: the depth 15, .061 of an inch; the width C, .080 of an inch; the width D, .060 of an inch: the pitch E, .375 of an inch; the radius F of the lug fillets, A 01 an inch; and the radius F of the rib fillets, of an inch.

In the case of the above example of a heavy bar, the core 40 is 1.360 of an inch diameter; the depth B, .085 of an inch; the width C, .100 of an inch: the width D, .080 of an inch; the pitch E, .603 of an inch: the radius F of the lug fillets, of an inch; and the radius F of the rib fillets A0 of an inch.

The fillets are provided primarily for the purpose of avoiding pockets or corners which could not be readily reached and filled by concrete when the same is used for reinforcing purposes.

Whereas the sides of the lugs have been referred to as "angular as determined by the angle G, it is apparent that the fillets may be enlarged to give a general concave configuration to the sides of the lugs, provided, however, that the effective angularity thereof doesnot exceed the angle determined by angle G.

As previously pointed out, angle G as deter- :5 mined by the formula, marks the limit of approach to the vertical that may be utilized without wiping, and in consequence greater angles or concavities for fillets which come within the efi'ective rule of the formula may also be employed without suffering the damage of wiping during the bar-forming process.

By virtue of the fact that the lug-forming grooves on the rolls are inclined in relation to the axis of the bar, all trapping of steam or water between the rolls during the bar-forming operation is avoided, with the manifest advantage of avoiding spelling or similar damage to the rolls and lugs,

As shown in Figures 8 and 9, the diametrically opposed sets of lugs 43' and 44' may be arranged in staggered relation instead of meeting relation as shown in Figure 6. The degree of displacement may vary in any particular case.

By virtue of the spiral disposition of the lugs in the form of bar illustrated in Figure 6, as well as that illustrated in Figure 8, the bars so constructed will have the same cross-sectional area in every transverse section, provided the lead of the lugs is sufficiently great in relation to their pitch. This fact adds greatly to the ease of rolling and, in addition, is productive of a bar having greater uniformity of strength throughout its length.

In the cases of the bars of particular sizes mentioned in the above-stated examples, the leads of the lugs of the several bars as set forth are the minimum permissible if the bar is to have the same cross-sectional area throughout its length. However, the pitches may be made greater than specified in the above examples and still maintain a uniform cross-sectional area throughout the length of the bar.

It will usually be desirable to provide a bar having the highest permissible lugs and the steepest possible angle on the leading face of the lug. Bars so construced have the maximum bonding effect when embedded in concrete. Consequently, the first formula given above may be employed for determining the maximum height of the lugs for a bar of a particular size, and thereafter the second formula may be employed to determine the steepest permissible angle for the leading faces of such lug. In this manner undesirable wiping or damage to the bar and rolls may be avoided. Of course, if lug heights less than the maximum are desired, the second formula may still be employed for providing a leading side face on the lugs of the greatest possible steepness.

It is apparent that the bar produced by the rolls of this invention will possess all of the properties described and claimed for it in applicant's said continuation-impart application Serial No. 537,125 and its parent application Serial No. 501,- 553.

Whereas the rolls of this invention have been illustrated as having the lug-forming grooves disposed in opposite directions, or, in other words, as segments of spirals of opposite hand, this invention extends to rolls having lugs oi diiferent construction and arrangement. such as, for instance, rolls having opposed sets of lugs inclined or spiraled in the same direction. In all events, it will be apparent that a new and useful method is provided, together with improved rolls, whereby the pass grooves which extend substantially 180 of the diameter of the bar to be formed are provided with lug-forming grooves cut into the sides and the base of the pass grooves, and further that the rolls may be utilized as the final finishing rolls in the usual rolling mill for produc tion of bars of superior construction and quality.

I claim:

1. e process of forming a pair of rolls for rollin g miis-or the like, which comprises cutting a circumferential pass groove-of substantially semicircular cross-section in each of said rolls in such position that said grooves cooperate to form a pass opening when said rolls are associated in operative position, thereafter rotating each of said rolls on its axis, and dur lgiucb-mt flm' ing a spir se series of cutting elements on axis while sai last-.nan 1 e d a d WW to the surmollb eing processe at the location of the center of the pass groove therein, advancing said series of ngtating cutting elements bodily o I cl l I' o I l the axis of said series of rotating cutting parallel to said tangent and thereby cutting in each of the sides of said pass groove 9. series of notches, each equally spaced around the circumference of said pass groove and continuing the advancement of said series of rotating cutting elements while maintaining the same parallel to said tangent, until said series of cutting elements has extended said notches to the base of said pass groove and formed in said pass groove a series 10 of lug-forming grooves extending generally transversely of said pass groove.

2. The process defined in claim 1, further characterized in that the series of lug-forming grooves of one of the rolls of each pair of rolls is out by rotating the spirally disposed series of cutting elements in contact therewith, as defined, of one hand. and the series of lug-forming grooves of the other of said rolls of each pair of rolls is cut by rotating the spirally disposed series of cutting elements in contact therewith, as defined, of the opposite hand.

3. The process defined in claim 1, further characterized in that the series of lug-forming grooves of one of the rolls of each pair of rails is cut by rotating the spirally disposed series of cutting elements in contact therewith, as defined, of the one hand and while rotating said roll in one direction, and the series of lug-forming grooves oi the other of said rolls of each pair of rolls is cut by rotating the spirally disposed series of cutting elements in contact therewith, as defined, of the opposite hand and while rotating the roll in a direction opposite to that of the first roll of said pair 01 rolls.

4. The process defined in claim 1. further characterized in that the rotation of said rolls is synchronized with the rotation of the spirally disposed series of cutting elements in cutting association therewith, whereby a predetermined number of substantially uniformly spaced lug-forming grooves are formed in theD roo s of S d rolls extending entirely around the circumferences thereoi, respectively.

5. The process defined in claim 1, further characterized in that the pitch of said spirally formed grooves is determined by enlarging the pitch of the lugs to be provided on the finished bar to be rolled thereby, by the shrinkage of said bar during cooling after rolling. and diminishing the sum thereof by the elongation of said bar during the rolling operation.

VICTOR M. SURERUS.

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

UNITED STATES PATENTS Number Name Date 1,609,045 Witherow Nov. 30, 1926 1,714,109 Schurr May 21, 1929

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