US3210977A

US3210977A - Rolling steel plate

Info

Publication number: US3210977A
Application number: US248422A
Authority: US
Inventors: Charles W Barrett
Original assignee: Republic Steel Corp
Current assignee: Republic Steel Corp
Priority date: 1962-12-31
Filing date: 1962-12-31
Publication date: 1965-10-12
Anticipated expiration: 1982-10-12
Also published as: FR1384201A

Description

Oct. 12, 1965 w. BARRETT ROLLING STEEL PLATE 3 Sheets-Sheet 1 Filed Dec. 51, 1962 INVENTOR. Char/es VZ/Barreff Af/omey Oct. 12, 1965 c. w. BARRETT ROLLING STEEL PLATE 3 Sheets-Sheet 2 Filed Dec. 31, 1962 E A m C S R E W R LK O AA WT 2 /0 .wmw w 3 G 5 0 W H ID I T r m Iw w m .I 5

F/GZ

VERTICAL EDGER ADJUSTING MOTOR I I l l I I I Al/omey Oct. 12, 1965 w. BARRETT 3, 7

ROLLING STEEL PLATE Filed Dec. 31, 1962 3 Sheets-Sheet 3 u I Jul/mm! 29 lllllllllllllll u id s INVENTOR.

United States Patent 3,210,977 ROLLING STEEL PLATE Charles W. Barrett, Clarence, N .Y., assignor to Republic Steel Corporation, Cleveland, Ohio, a corporation of New Jersey Filed Dec. 31, 1962, Ser. No. 248,422 12 Claims. (Cl. 72-16) This invention relates to the rolling of steel plate, and is particularly directed to apparatus and procedure for the rolling of flat steel plates used in the fabrication of pipe, and also steel plates of desired width, for other purposes.

Steel pipe, especially that of relatively large diameter, e.g., 20 inches or more, and having a wall thickness, for example, of fitth to %th inch or greater, is manufactured from elongated flat steel sheets or plates known as skelp, which may be as much as 25 to 30 feet long or more, and 6 to 10 feet wide. To form a pipe section, a sheet of skelp is bent or rolled to a cylindrical configuration about an axis parallel to the long dimension of the skelp, so that it has the desired tubular shape, with the longitudinal edges of the sheet meeting to form a cleft along one side of the pipe blank; this cleft is subsequently welded, to produce a finished pipe section. As therefore appears, the long dimension of the skelp sheet becomes the length of the pipeblank section; the thickness of the sheet becomes the thickness of the pipe blank Wall; and the width of the sheet becomes the circumference of the pipe blank.

The dimensions of the skelp sheet must accordingly be chosen to provide the desired dimensions, and particularly the desired wall thickness and circumference, in the finished pipe. The skelp sheet is typically prepared from a comparatively thick, elongated steel slab by passing the slab through a rolling mill to reduce it in thickness to the desired wall thickness of the pipe to be produced. Specifically, the slab is passed through the rolling mill in the direction parallel to its short dimension or width. In this way, the slab is greatly elongated during the rolling operation, in the direction of its width, such that the long dimension of the skelp sheet produced corresponds in orientation to the width of the original slab, while the long dimension of the original slab, unchanged during the rolling operation, becomes the short dimension or width of the skelp sheet. The desired skelp sheet thickness is obtainable by this simple rolling operation; however, before bending the skelp sheet to form pipe, it has heretofore been necessaryto trim the side edge of the skelp sheet considerably, in order to shape it to the desired width, i.e., the desired circumference of the pipe blank to be produced. Such trimming 'is both inconvenient and wasteful of steel, and is time consuming.

Steel plate used for pipe is commonly called skelp, and when sold for other purposes is known as plate; for convenience, the expression plate product is adopted herein to mean plate generally, whether employed as skelp or otherwise.

It is accordingly an object of the present invention to provide an improved, economic and efficient method of rolling plate products, with certain special advantages in the case of skelp but with significant utility in making plate for other purposes as well. Another object is to provide such a method wherein a large amount of side trimming, and consequent steel wastage, is obviated. Another object is to provide a method of rolling plate products, especially skelp, of a uniform predetermined Width. A further object is to provide improved procedures for working a steel slab or plate to a predetermined length. A still further object is to provide apparatus for facilitating the performance of such procedures.

To these and other ends, and taking the manufacture "ice of skelp as an example of operation applicable to the making of plate products generally, the present invention contemplates working a rough steel slab to a predetermined length, viz. the desired skelp width (which is the desired circumference of the pipe to be formed), by rolling it to reduce its thickness to a value determined. from the length desired, and the weight, width, and density of the slab; and rolling the slab, as thus worked, in a direction parallel to the short dimension of the slab to form a skelp sheet having a uniform predetermined width, approximately equal to or slightly greater than the length of the Worked slab. These rolling operations are of the character known as hot rolling, the slab being at an elevated temperature for the working operation in the rolling mills.

The manner in which the slab is rolled to a predetermined length constitutes an essential and particularly important feature of the invention. The rough slab is first passed through a vertical edger, consisting of vertically disposed rolls, adapted to reduce the width of the slab as it is passed between them, and adjustably positionable so that their horizontal spacing may be varied to reduce the slab to a predetermined width. The edger, having been set for a convenient Width, shapes the slab passed through it to that width, by deformation. The slab is weighed, and advanced toward a suitable stand of horizontal rolls, conveniently a rolling mill such as the type known as a scalebreaker, or such as a type used or known as a first rougher, consisting of horizontally disposed rolls in spaced vertical relation, adapted to reduce the thickness of a slab passed between them, and adjustably positionable so that their vertical spacing may be varied to reduce the slab to a predetermined thickness. In the following description, this mill is identified as a so-called scalebreaker, but it will be understood that such reference is merely by way of specific example and that any of various other types or designations of mills would be appropriate for the described reduction of slab and is thus equally contemplated for use in the invention.

Before the slab reaches the scalebreaker mill (or other roughing mill of similar suitability), the vertical spacing of the scalebreaker rolls is adjusted such that the scalebreaker will reduce the slab to a thickness 1 of a value determined by the equation wherein G represents the weight of the slab as determined in the weighing step; L represents the desired predetermined length to which the slab is to be worked (being a value which, When increased by the small amount of lateral spread expected in rolling the slab into skelp, and diminished by the small amount of finish trimming or grinding that is necessary for dimensional precision in making pipe, is equal to the desired circumference of the pipe blank to be formed); W represents the width of the slab, i.e., the predetermined value to which it is shaped in the vertical edger; and D represents the density of the slab, in convenient units.

When the scalebreaker mill is thus adjusted, the slab is advanced to and passed between the scalebreaker rolls, in the direction of the long dimension of the slab. It is thereby reduced to the thickness 1., and at the same time is progressively elongated; as it emerges from the scalebreaker mill, the thickness of the slab is uniformly of the value t, and the length of the slab is found to have the desired predetermined value L. In other words, by reducing the thickness of the slab in a horizontal rolling operation, to a value determined from the desired length and the slab weight, width, and density, the desired length is achieved; i.e., while reducing the thickness to that value, the rolling operation concomitantly eifectuates elongation of the slab to exactly the desired slab length. This result is attained by the aforementioned steps of adjusting the relative positions of the scalebreaker rolls for slab reduction to the computed thickness, and passing the slab between the rolls in the direction of its long dimension, as described above. The preceding edging operation, moreover, cooperates significantly in achievement of the stated result, as it establishes a predetermined width for the slab in a simple and positive manner, without waste and with dimensional accuracy and uniformity throughout, i.e., from end to end, such width being one of the factors essential to the described adjustment of the scalebreaker rolls.

Having thus been shaped to the desired length, the slab is ready to be worked into a skelp sheet for pipe formation, as by further rolling operations, the slab being passed through a rolling mill, in the direction of its short dimension or width, until it is reduced in thickness to the thickness desired for the wall of the pipe blank. It is thereby greatly elongated in the direction of its original short dimension, which as elongated becomes the long dimension of the skelp sheet. The original long dimension of the slab, however, remains substantially unaltered (i.e., except for normal spread), becoming the short dimension or width of the skelp sheet. Since the long dimension of the slab has been made such as to predetermine, approximately, the desired pipe circumference, the resultant skelp sheet has a width uniformly and closely related to that desired circumference, i.e., being just slightly in excess, so that after only very minor side trimming it may be rolled or bent into a pipe blank. Hence the process practically eliminates, or at least reduces to a minimum, all waste-productive trimming of the side edges of the skelp. Stated in another way, metal to the extent of several inches Width of trim is saved and employed, in effect, as useful addition to the length of the plate product.

A particular advantage of the invention, especially in the complete process including the edging operation on the slab, is that no dimensional measurements are required to be taken of the slab, either as to length, width or thickness. The only determination is the simple one of weighing the slab, yet the process achieves a finished slab accurately dimensioned in length L (and indeed also in thickness) for the stated, special utility in conversion to skelp. Considerable variation in size of successive rough slabs is fully accommodated, the basic requirement being simply that the slab be originally shorter than the ultimately desired length L, while the width setting W of the edging pass is conveniently selected as slightly less than the narrowest slab expected.

The present invention also embraces apparatus for the performance of the above-described process. The apparatus contemplated includes a computer or like device, adapted to perform the mathematical operation hereinabove set forth for calculation of the value 2, a scalebreaker or other suitable mill as referred to above, including means for adjusting the mill rolls as described, and a scale, adapted to weigh the slab to be rolled before it is advanced to the scalebreaker or rougher mill. Means are also provided for automatically communicating a signal representative of the slab weight to the computer, and for automatically communicating a signal representative of the result t of the computer calculation to the means for adjusting the scalebreaker rolls. Data representative of the slab width and density and the desired length are fed to the computer, which is adapted to perform the calculation of the value t automatically on receiving the weight signal from the scale, if it has first been supplied with these other necessary data. On completion of the computation, the signal representing the value 1 is automatically communicated to the scalebreaker adjusting means, which are adapted to be automatically by this signal to adjust the scalebreaker rolls to provide for reduction of the slab to the thickness t.

Thus, with such apparatus, advance of the slab to the scale (e.g., from a vertical edger which shapes the slab to a predetermined width, as explained before) initiates an automatic sequence of operations culminating in adjustement of the scalebreaker rolls to a position that will reduce the slab to the requisite thickness for the desired length. In a complete system for working a rough slab to a finished skelp sheet in successive operations, the apparatus just described is associated with a vertical edger, coacting in its important function of imparting the predetermined width to the slab before horizontal rolling, and with a further rolling mill or the like to roll the shaped slab to the final skelp sheet.

Further features and advantages of the invention will appear from the more detailed description hereinbelow set forth, together with the accompanying drawings, wherein FIG. 1 is a diagrammatic illustration, in perspective, of the working path of a slab as it is shaped into a skelp sheet in accordance with the present invention;

FIG. 2 is a diagrammatic plan view of the arrangement of principal components in apparatus constituting one embodiment of the invention; and

FIG. 3 is a diagrammatic perspective drawing of a horizontal scalebreaker or rougher rolling mill, such as could be used with the present invention, illustrating means for adjustably positioning the rolls.

Referring to the drawings, a rough slab 10 to be worked is illustrated as being advanced along a rectilinear path parallel to its long dimension. A vertical edger, represented by vertically disposed rolls 11, 12, is located along the path, adapted to engage the advancing rough slab 10 and reduce the Width thereof as it passes through the edger. As shown, the rolls 11, 12 are disposed at either side of the path, and are adapted to rotate about parallel vertical axes contained in a plane perpendicular to the path of the slab 10. Thus the two rolls engage the leading edge of the slab 10 at opposite sides thereof and deform the slab so as to reduce its width by their mutual pressure as it is advanced through the restricted space between them. Means of conventional character (e.g., the vertical edger adjusting motor 13 diagrammatically indicated in FIG. 2) are desirably provided for adjustably positioning the rolls 11, 12 so as to vary the horizontal distance between them to provide for reduction of the slab to a width of predetermined value. It will be understood that instead of edging rolls as presently preferred, other shaping means can be used to reduce the width of the slab to a predetermined standard value, e.g., a conventional hydraulic or other press, such as a side press, sometimes called a squeezer.

The slab, as reduced in width to a uniform predetermined value on emergence from the vertical edger, is indicated at 15. Means are provided for ascertaining the weight of the slab, illustrated as a scale 16 set in the path of the advancing slab. The scale may, for example, be of a known type provided with load cells (not shown), i.e., cells containing strain gauges of conventional character, for the determination of the slab weight; these cells, functioning in their conventional manner, produce an electrical signal representative of the weight of the skill) when it is placed on the scale and is carried by the ce s.

A horizontal scalebreaker or like rolling mill, represented by horizontally disposed rolls 17, 18, is located along the path of the slab, adapted to engage the againmoving slab after it has been weighed (and released) by the scale 16, such scale comprising, if desired, a vertically-movable, load-cell-supported assembly (not shown in detail) to engage the slab and lift it momentarily above its path. The

rolls

17, 18, as shown, are adapted to rotate about parallel horizontal axes contained in a plane perpendicular to the working path of the slab, and are disposed in vertical spaced relation. They are further 5, adapted to mutually engage the slab as it is advanced between them, and to reduce its thickness by their mutual pressure as it passes through. Means, such as the scalebreaker screw-down motor indicated in FIG. 2, are provided for adjustably positioning the

rolls

17, 18, e.g., by adjusting one of them relative to the other, to vary the distance between them and thus to vary the thickness to which they will reduce the slab.

The screwdown device for the mill constituted by the

rolls

17, 18, may be of well-known, conventional construction, as indeed are these and all other parts of each of the several mills, weighing scale and other elements of the system shown, but for completeness of illustration and by way of example, a schematic view of one type of a motor-driven screwdown, in highly simplified form, is shown in FIG. 3, from which the operation of the roll-adjusting step will be readily understood. Thus one of the rolls, for example the upper roll 18, of the scalebreaker mill may be journaled in suitable blocks, such as the block 26, at either end, the blocks being vertically displaceable within frames 27 which define paths of vertical travel for the respective blocks. Vertically disposed threaded positioning screws 28 impinge upon and extend upwardly from the upper faces of the respective blocks 26, through the upper ends of the respective frames 27. Above the frames, each screw 28 passes through an internally threaded worm wheel 29 which is rotatable but restrained from vertical displacement, and arranged so that horizontal rotation of the wheel 29 causes vertical displacement of the screw 28. Horizontal worms 30 engage the worm wheels 29 and are connected, as by a shaft 31, to a motor or motor drive unit 32. When the worms 30 are driven by the motor, they effect rotation of the wheels 29, which in turn effects vertical displacement of the screws 28 and consequent vertical displacement of the blocks 26 against which the screws impinge, i.e., vertically displacing the roll 18 or its operating position and thus altering its vertical spacing, when in use, relative to the roll 17.

For the sake of convenience, the entire screwdown device, such as the arrangement of blocks, screws, worm Wheels, worms and motor described above, will be hereinafter comprehended, and thus understood as brought into or out of operation, when reference is made to the horizontal scalebreaker screwdown motor, it being further understood that the arrangement as shown and described is exemplary'only, and that any suitable alternative arrangement for adjustably positioning the scalebreaker rolls relative to one another, i.e., for adjusting their effective spacing, may be employed with the invention. Moreover, ordinarily the roll stand should also have the customary means for separately adjusting the rolls at one end relative to the other so that by such adjustment at the outset and from time to time as needed, the upper and lower rolls can be kept effectively parallel; such means, which require special adjustable coupling (between or to the screwdown drive elements 30), or other suitable mechanism, i.e., instead of the common rigid shaft 31, are entirely conventional and therefore omitted from the drawings.

In the operation of the scalebreaker, it is adjusted (as by the scalebreaker screwdown motor) to reduce the slab advanced through it to a uniform thickness equal to the arithmetic ,quotientof the weight (obtained by weighing the slab in the scale 16) divided by the arithmetic ,product of the length of slab desired to be achieved, width of the slab (as provided in the vertical edger), and density of the slab. The latter three values are all known or predetermined.

Very advantageously, the adjustment of the scalebreaker may be effected with apparatus of the character illustrated diagrammatically in FIG. 2. This apparatus includes a computer 33 adapted to compute the thickness t by the above-described mathematical operation, means 33a for communicating a signal representative of the slab weight G from the scale 16 to the computer (e.g. the electric signal from load cells in the scale, representative of the weight, as described above), and means 33b for communicating the computed thickness t from the computer to the scalebreaker screwdown motor. Data representative of the desired slab length L, the slab Width W, and slab density D are fed to the computer, as indicated collectively at 34. The computer 33 is adapted, when supplied with these data, to be actuated automatically by the weight signal G from the scale 16 to perform the computation, and transmit the computed thickness t to the scalebreaker screwdown motor, which is in turn adapted to be actuated automatically by this signal from the computer, to adjust the scalebreaker rolls in accordance therewith.

It will be understood that the computer 33 may be of conventional design, as likewise all necessary electrical translating or control means (not shown) intermediate the scale 16 and the computer, and intermediate the computer and the scalebreaker screwdown motor 32. Means are commonly known and used for adjusting screwdown motors of rolling mills in accordance with electrical signals of the type employed in and emitted by electronic computing systems, and in similar fashion, especially in that the response of the load cells in the scale 16 is electrical in nature, the weight determination of the scale 16 is effectively translated or converted into a suitable signal for the electronic computer 33, for example in that the load cells are conventionally connected to deliver a voltage signal representative of weight, being an analog signal, and conventional means are known and available for converting such an analog signal into a digital signal as required by the computer, to effectuate its computing operation.

Thus it will be understood that the electrically responsive scale assembly 16, with supplemental, conventional devices (not shown otherwise than by the connection 33a), includes appropriate electrical translating or converting means of known character, for feeding into the computer a signal (e.g., of digital type) numerically representing the determined weight G. Similarly, the screwdown motor 32 may be understood to include suitable control devices, of known type, receiving an electrical signal from the computer 33, having or representing the numerical value of the desired thickness t, whereby the motor is actuated to drive the screwdown to a position Where the rolls 17, 18 (FIGS. 1 and 3) have a spacing appropriate to deform the slab to such signaled thickness.

The values of the desired slab length L, width W and metal density D can be manually set in the computer by appropriate means or established by feed of one or more suitably punched cards. As will be understood, the values of corrected slab width W and density D may remain the same for a continuing run of slabs of identical composition and roughly similar dimensions, the width W being that which is set up in and achieved by the edger 13 in its corrective deformation of the incoming rough slabs 10. The length L, of course, is the corresponding constant value desired for the finished slab 35, i.e., being determined by the diameter desired for the ultimate pipe to be manufactured.

Although if desired the actual computing operation of the device 33 may be initiated manually after the Weighing operation, this computer 33 can advantageously be set to function automatically, i.e., being triggered by receipt of the weight signal G, whereby the scalebreaker screwdown is thereupon promptly adjusted for the desired thickness t (in accordance with the signal delivered as the result of the computation), in suitable time for the-pass of the slab, as the latter moves or is moved from the scale into the scalebreaker rolls.

The slab, as thus reduced to the computed thickness t by passage through the scalebreaker mill in the direction of its long dimension, is indicated at 35 in the drawings. It now has the desired length L, having the intended relation to the width (e.g., slightly less than such width, by

determinable amount) which is required for the ultimate skelp. The further working path of the shaped slab 35 beyond the point thus indicated is illustrated as forming a right angle with the path of the slab prior to that point, and a skelp rolling mill, comprising rolls 36, 37, 38, 39 is shown, representing means for reducing the thickness of the slab to the desired pipe blank wall thickness, so as to form a finished skelp plate 40. To that end the slab 35 is passed through the skelp rolling mill between rollers 38, 39, in the direction of its short dimension or width, i.e., at a right angle to the direction in which the slab has previously been advanced. As illustrated by way of example, the skelp rolling mill is a so-called 4-high mill, having large pressure or back-11p rolls 36, 37 and smaller contact or work rolls 38, 39, the contact rolls being driven by suitable means in the usual way. The skelp rolling mill is conveniently of reversible character, arranged so that the slab 35 may be passed back and forth through the mill in successive oppositely directed passes (along a path parallel to the original short dimension of the slab), until reduced to the desired skelp thickness. As will be understood, the plate or skelp mill may alternatively be of 3-high or any other type suitable for the described purpose.

In performing the process, the steel slab to be shaped is worked throughout at an elevated temperature, the operations being all of the character known as hot rolling. The vertical edger adjusting motor is first set, to position the vertical edger rolls 11, 12 for working a slab, passed between the rolls, to a convenient predetermined uniform width. A heated rough steel slab is then advanced through the edger, i.e., between the rolls 11, 12, in the direction of its long dimension. It is thereby shaped to the aforementioned predetermined width (herein referred to as W). The slab is then advanced to the scale 16, where it is weighed automatically (i.e., on being brought to and upon the scale), for example by load cells, which produce an electric signal representative of the slab weight responsive to the pressure of the slab weight on the cell. The weight of the slab (herein designated G) is automatically signaled to the computer. As explained above, data respecting the width W, the length to which it is desired to shape the slab (i.e., chosen to suit the circumference of the pipe blank to be produced, and here designated L), and the density of the slab (here designated D) have been previously fed to or otherwise established in the computer, which has been set to compute a thickness t from these data according to the equation Upon receiving the weight signal G from the scale 16, the computer is automatically actuated to perform the computation. Having computed the thickness t, the computer automatically signals this value to the scale-breaker screwdown motor. Responsive to the signal, the latter motor automatically adjusts the relative position of the

rolls

17, 18, so that the slab 15 will be reduced to the thickness t on passage between the rolls. The slab is then advanced to and between the

rolls

17, 18, in the direction of its long dimension, i.e., with its long dimension perpendicular to the axes of the

rolls

17, 18. Very preferably with a single, unidirectional pass through and beyond these rolls, it is shaped to a thickness of the uniform value t, and by the reduction in thickness is concomitantly elongated, in the direction of its long dimension, to a length which is found to be equal to the length L. If for any reason it is desired to utilize more than one pass for this operation, the rolls are progressively adjusted, reaching the setting needed for the computed thickness 1, on the final pass.

The shaped slab 35 is then subjected to further rolling operations, as in the skelp rolling mill represented by rollers 36, 37, 38, 39, to reduce it to the desired pipe blank wall thickness and thus to form a finished skelp sheet. It is passed through the skelp or plate rolling mill convenience.

in the direction of its short dimension or width, in successive oppositely directed passes until reduced to the thickness desired, so that it becomes greatly elongated (e.g., to a length of twenty-five to thirty feet or more) in that direction (i.e., the direction of the width of the slab 35), while its original long dimension (shaped to the length L) remains unchanged except for the normal and unavoidable sidewise spread of rolling. Consequently, the finished skelp sheet 40 has a long dimension in the same direction as the short dimension of the slab 35, while the long dimension of the slab becomes the short dimension or width of the sheet 40, which has been determined by the value L, and which very closely approximate the desired circumference of the pipe to be made from the skelp. The skelp sheet 40 is therefore ready to be formed into a pipe blank (as shown at 40a in FIG. 1), as by bending (e.g. in suitable presses) or rolling about an axis parallel to its long dimension, after a predetermined minimum of side trim has been removed.

That is to say, there is a finish grinding or trim of the skelp edges, as for desired squareness or shape for abutment and to achieve precision of dimension as to the width of the skelp. In the manufacture of plate to be sold for other purposes, it may sometimes be unnecessary to do any grinding or cutting at all (or only to a very slight extent) by way of sizing. In each case there is little or essentially no waste of steel by edge trimming.

The arrangement of elements in the working path of the slab may of course be varied to suit operational Thus, while the scale 16 has been illustrated as positioned between the vertical edger rolls 11, 12 and the scalebreaker rolls 17, 18, any other arrangement could be used for weighing the slab before it reaches the scalebreaker rolls 17, 18, which must be adjusted in mutual position in accordance with the weight ascertained. For example, the weighing could be per formed before the rough slab passes through the vertical edger rolls 11, 12, since the weight of the slab is not altered by that edging step. Again, while the path in which the slab 35 is worked to a finished skelp sheet 40 has been illustrated as forming a right angle with the previous working path of the slab, the entire working path could be rectilinear with the slab 35 rotated after through the scalebreaker rolls 17, 18 so that subsequent rolling into skelp sheets will be performed, as with the right-angle path, in a direction parallel to the short dimension of the slab and at right angles to the long dimension L.

With the present invention, skelp sheets or plates of the same thickness and Width may be formed from rough steel slabs of varying dimensions and mass. Thus assuming several skelp sheets of a given thickness and width are to be formed from rough steel slabs 10, and assuming further that the slabs 10 vary in size, all the slabs after passage through the scalebreaker rolls 17, 18 (i.e., as shaped slabs 35) will have the same desired length L. Any variations in size between the slabs 10 will be reflected in variations of the thickness of the slabs 35, the thickness produced by the scalebreaker mill being computed with reference to a given desired length and also with reference to the width, weight, and density of the particular slab, according to the equation set forth above. For example, if the ultimate skelp width is to be 96 inches (the finished slab length L being then slightly less by a predeterminable amount), and if the vertical edger deforms each rough slab 10 to a width W selected as 45 inches, and if the density of the steel is 0.282 pound per cubic inch, then for slabs having a weight G of the order, say, of 3 tons (6,000 pounds), the

mill

17, 18 will be automatically set to yield finished slab 35 of a computed thickness, of the order of 4.9 to 5 inches, that will yield the exact length L, which is approximately 96 inches less an allowance for spread in the plate mill, which may be found, for instance, to be of a value up to about one inch. This allowance for spread can be readily determined by experience and observation, and depends, as will be understood, on the thickness of the slab, the amount of reduction, the temperature, the grade of steel, and the size of the mill; approximation of the allowance (for determining L) can be easily made by persons skilled in rolling practice, and minor corrections, as necessary, can be effected in the course of operations.

The stated result L, of the above example, is readily attained over a substantial variation of dimensions of the rough slab 10, for instance a width range of 45 to 48 inches, an original thickness range of up to an inch or more above the computed value t in any instance, and a very wide range in original length and weight of the slab 10. v

The further rolling operations in the skelp or plate mill (rolls 36, 37, 38, 39) impart a uniform thickness to all the slabs, e.g., the desired Wall thickness for the pipe blank, While not altering their uniform dimension L, other than by normal spread, which becomes the short dimension or width of the finished skelp sheets 40. The sheets 40 may, however, vary in their long dimensions according to the size of the original rough slabs that is, the variations in size of the slabs 10 are ultimately reflected only in the long dimension of the sheets 40, which is the least critical of the skelp sheet dimensions. Indeed variations in length of the finished pipe section are ordinarily of no consequence; large-diameter pipe, as a batch or lot of sections, is conventionally sold by total length of the lot, so that minor differences among lengths of sections are accounted for in the total but disregarded individually, especially for most uses as in pipelines running for miles or more.

The described procedure and system are also advantageous in making other plate products than skelp, i.e., plate for other purposes, as where a particular width has been specified and extra tonnage represented by excess width is not wanted and would otherwise be wasted as trim. Indeed also where plate is to be made to a minimum length, the present invention is of value in getting the most length possible out of every slab, thus reducing or avoiding the production of short plates that do not meet requirements. Very notably in the case of skelp, but likewise for the plate products generally, the present process affords a markedly improved yield: metal that would otherwise be lost as trim is now, in effect, usefully added to the product in the form of additional length.

It is to be understood that the invention is not limited to the operations and embodiments hereinabove specifically described, but may be carried out in other ways without departure from its spirit I claim:

1. A method of shaping a metal slab of ascertained width, weight, and density, to a desired predetermined length, comprising rolling said slab, in the direction of said length, to a thickness determined as the arithmetic quotient of said ascertained weight divided by the arithmetic product of said length, said width, and said density.

2. A method as defined in claim 1 which includes weighing the slab, prior to said rolling operation, to ascertain its aforesaid weight.

3. A method as defined in claim 1 which includes establishing said ascertained width of the slab by shaping the slab to said width by edgewise deformation thereof.

4. A method of rolling a plate product, comprising shaping a metal slab to a predetermined length as defined in claim 1, and rolling said shaped slab, in a direction at right angles to its long axis, to a predetermined thickness to provide an elongated plate product which has a predetermined uniform width determined by said predetermined length of the slab.

5. A method of rolling a plate product as defined in claim 4 which includes weighing the slab, prior to the 10 first-mentioned rolling operation, to ascertain its aforesaid weight.

6. A method of shaping a metal slab of ascertained density to a predetermined length, comprising shaping said slab to a predetermined width by edgewise deformation, weighing said slab, and thereafter rolling said slab, in the direction of said length, to a thickness determined as the arithmetic quotient of the weight of said slab divided by the arithmetic product of said predetermined length, said predetermined width, and said density.

7. A method of shaping a metal slab as defined in claim 6, wherein said shaping step is effected by edgewise rolling the slab to said predtermined width and said Weighing step is performed intermediate said edgewise rolling step and the first-mentioned rolling step, said first-mentioned rolling step comprising passing the slab between horizontal rolls, including adjusting the spacing of said rolls in accordance with said quotient value, to reduce the slab to said thickness.

8. A method of rolling a plate product, comprising: shaping a steel slab of ascertained density to a predetermined length by procedure which includes weighing the 'slab and which comprises shaping the slab by edgewise deformation to a predetermined width,- and thereafter rolling the slab in the direction of said length to a thickness determined as the arithmetic quotient of the weight of the slab divided by the arithmetic product of said predetermined length, said predetermined width and said density; and rolling said slab, as shaped to said predetermined length, in a direction at right angles to said length of the slab, to a predetermined plate thickness to provide an elongated plate product which has a predetermined uniform width determined by the aforesaid predetermined length of the slab.

9. A method of rolling a plate product, which comprises passing a steel slab of ascertained density between vertical rolls adapted to rotate about parallel vertical axes disposed in a plane perpendicular to the path along which said slab is passed, to shape said slab to a predetermined uniform width, the distance between said rolls being preset to effectuate such shaping of the slab to said predetermined uniform Width, weighing said slab, reducing the thickness of said slab by rolling it, between horizontal rolls adapted to rotate about parallel horizontal axes disposed in a plane perpendicular to the long axis of said slab, said slab being passed between said rolls along a path parallel to the long axis of said slab, to shape said slab to a predetermined uniform length, automatically producing a signal representing the thickness required for said slab to attain said predetermined length, by computation of the arithmetic quotient of the weight of said slab divided by the arithmetic product of said predetermined length, said predetermined width and the density of said slab, adjusting the vertical spacing of said horizontal rolls under control of said signal for effectuating said shaping of the slab to said length by reducing it in the aforesaid rolling operation to the aforesaid thickness, and rolling said slab, after passage through said horizontal rolls, in a direction at right angles to the long axis of said slab, to a predetermined thickness to provide an elongated plate product of predetermined uniform width determined by said predetermined length of the slab.

10. In apparatus for rolling a flat steel piece to reduce the thickness thereof, the combination of a horizontal rolling mill adapted to reduce the thickness of a steel piece passed therethrough, means for adjusting said mill to vary the thickness to which it will reduce a steel piece passed therethrough, means for performing the mathematical operation which is defined by the step of multiplying together the width of a steel piece, the density of said piece, and the length to which it is desired to shape said piece and the step of dividing the weight of said piece by the product of said multiplying step, means for weighing said piece before it is passed through said mill, means for automatically communicating a signal representative of the weight of said piece from said weighing means to said means for performing said mathematical operation, said last-mentioned means, when supplied with data representative of said width, said density, and said desired length, being automatically actuated by said signal representative of said weight to perform said mathematical operation, and means for automatically communicating a signal representative of the quotient obtained by said mathematical operation to said means for adjusting said mill, said adjusting means being adapted to be actuated automatically by said signal representative of said quotient, to adjust the mill to reduce a steel piece passed therethrough to a thickness equal to said quotient.

11. In apparatus for rolling a flat steel piece to reduce the thickness thereof and provide a finished piece having a predetermined length, in combination, a horizontal rolling mill adapted to reduce the thickness of a steel piece passed therethrough, means for adjusting said mill to vary the thickness to which it will reduce a steel piece passed therethrough, means for weighing the steel piece prior to its being passed through the rolling mill, means controlled by said weighing means for delivering a signal representing the weight of the piece, computing means controlled by said last-mentioned means and having means to receive data representing the width of the piece and the density of the metal thereof, for computing a value of thickness to which the sheet must be reduced by lengthwise rolling in order to be elongated thereby to a predetermined length, said computing means comprising means for calculating said thickness as the arithmetic quotient of the weight of the piece divided by the arithmetic product of said predetermined length, said width and said density, and means controlled by said computing means and in accordance with said calculated thickness for controlling the adjusting means to adjust the rolling mill to reduce the piece, on passage therethrough, to said thickness.

12. In a method of making a pipe blank, the steps of: shaping a steel slab of ascertained density to a predetermined length by procedure which includes weighing the slab and which comprises shaping the slab by edgewise rolling to a predetermined Width, and thereafter rolling the slab in the direction of said length to a thickness determined as the arithmetic quotient of the weight of the slab divided by the arithmetic product of said predetermined length, said predetermined width and said density; rolling said slab, as shaped to said predetermined length, in a direction at right angles to said length of the slab, to a predetermined skelp thickness to provide an elongated skelp sheet which has a predetermined uniform width determined by the aforesaid predetermined length of the slab; and thereafter shaping said skelp sheet into a cylindrical configuration about an axis parallel to the longer dimension of the skelp, to constitute a pipe blank.

References Cited by the Examiner UNITED STATES PATENTS 2,145,593 1/39 Gardner 60 FOREIGN PATENTS 484,943 5/38 Great Britain.

OTHER REFERENCES Control Engineering, January 1960, pages 126-130.

WILLIAM J. STEPHENSON, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No: 3, 210 ,977 October 12, 1965 Charles W Barrett It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 74, after "matically" insert actuated column 4, line 5, for "adjustement" read adjustment column 8, line 44, before "through" insert passage column 9, line 44, strike out "the"; column 10, line 13, for 'predtermined" read predetermined Signed and sealed this 21st day of June 1966.

(SEAL) Attest:

ERNEST w. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents