US1121154A - Method of rolling ingots. - Google Patents

Description

T. ALLDERDIGE.

METHOD OF ROLLING INGOT APPLICATION FILED AUG.7. 19

( Paterited Dec. 15.1914.

II/ III/III] FIG.1

A INVENTOR Z474 7M WITN ESSES UNITED STATES PATENT OFFICE.

TAYLOR ALLDERDICE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE NATIONAL TUBE COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORA- TION OF NEW JERSEY.

Application filed August 7,

To all whom it may concern.

Be it known that I, TAYLOR ALLDERDICE, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Methods of Rolling Ingots, of which the following is a specification.

l\ y invention has relation to the rollin of ingots in blooming mills, into bloomsjiillets, slabs, and similar products.

In casting ingots, the metal forming the outer surfaces of the ingots, which comes into contact with the surfaces of the ingot molds, solidifies more rapidly than the interior of the ingots. In this way a skin which has solidified is formed on the outer surface of the ingots while the interior of the ingots is still fluid, the ingot then gradually cooling to the point where it becomes solid.

Heretofore, in rolling ingots, it has been the practice to reduce the cross sectional area and elongate the ingots by applying rolling pressure on but two opposite sides thereof, in each of the sever. reducing passes to which the ingots are subjected. l/Vhen reduced in this way the thickness, or distance vertically between the two opposite sides, acted upon by the rolls is reduced and the ingot is lengthened. The other two opposite sides of the ingot (the ingots being rectangular in cross section) are forced outwardly into engagement with the side surfaces of the roll collars by the rolling pressure, so as to increase the Width or distance between the vertical sides of the ingot at the corners thereof, the increase in width being greatest at the corners and becoming less toward the neutral axis of the ingot.

There may be no increase inwidth on a horizontal line through the neutral axis and in some cases, when heavy enough reduction is put on the ingot, the ingot will increase in length to such extent as to stretch the ingot lengthwise and reduce it in width on the neutral axis, simultaneously with a much greater reduction in the thickness.

It will be understood, that in rolling ingets, the in ots usually are turned through an angle 0 90 degrees after one or more passes, to subject two opposite sides alter-- Specification of Letters Patent.

Patented Dec 15, 1914. 1914. Serial No. 855,638.

nately with the other two opposite sides of the ingot to the reducing action of the rolls. The roll collars, forming the vertical sides of the passes, are positioned with respect to each other so asto provide for the increase in width at the corners of the ingot, which occurs in such passes, the distance between the collars always being somewhat greater than the width of the ingot before it enters the pass.

When the corners of the ingots are forced outwardly as has been described the ingots frequently crack in the rolling operations and such cracks form defects in the surfaces of the ingots which frequently extend for some distance inwardly. If cracked in this manner it is practically impossible to remove the defects in the later rolling operations, so that the surfaces of the finished materials will have seams and other defects therein and in order to lessen the liability of cracking, the amount of reduction put upon the ingots in the early passes, when the ingot is hottest, is less than otherwise possible to put upon the ingot.

One object of my invention is to provide an improved method of rolling ingots, having novel means whereby all of the side surfaces of the ingot are supported and simultaneously acted upon in the early reducing operations, and the metal of the ingot is displaced from each side inwardly toward the center of the ingot, when the crystalline structure of th skin on the outer surface of the cast ingot is being changed and the thickness of this skin is being increased.

Another object of the invention is to provide a novel method of rolling ingots whereby the reductions put on the ingots in the earlier of the series of rolling passes to which the ingots are subjected, may be materially increased.

Still further objects of the invention will become apparent as the invention is more fully described hereinafter- In the drawings forming part of this specification, Figure 1 is an elevation showin one manner of forming the passes in the rofis of a two-high reverslng bloomin mill having horizontal rolls, so as to enab e my improved method being employed in rolling ingots. Fig. 2 is a transverse sectlon of anroll pressure or lines struction, for adjusting the rolls.

of the roll housings,

ingot of rectangular cross section showing the direction of application of the roll pressure or lmes of force in the first pass 01' passes, in rolling ingots by existing methods.

Fig. 3 is a similar section showing the action in the succeeding pass or passes used in the old methods of rolling ingots in working on theother two opposite sides of the ingot. Figs. 4 and 5 are similar transverse sections showing the direction of application of the of force in the first two reducing passes or first-two series of passes, in rolling ingots by my improved method.

In the accompanying drawings, the numeral 2 designates the bottom roll and 3 the vertically adjustable top roll of a twohigh reversing blooming mill, these rolls being provided oneach end with the usual roll necks 4: by which they are mounted in the roll bearings, and wabblers 5 by which the rolls are positively driven.

The rolls'2 and 3 are mounted in bearings which are removably secured in the windows and a roll adjusting mechanism is provided, of the usual con- This part of the apparatus not forming art of this inventionis omitted for the sea ness.

In operating two-high illustrated, the rolls 2 and 3 are adjusted relatively toward each other to form passes of successively smaller sizes, the top roll 3 generally being barrel of the rolls shown is a series of seven asses designated by the numerals 6, 7 ,8, 9,, 10, 11 and 12. Collars 13 of the usual construction are provided on the barrel of the rolls to separate one pass from the adjacent pass. The passes 8, 9, 10, 11 and 12 are constructed in the usual manner, so as to provide opposing cylindrical surfaces 14 on the barrel of the rolls-which engage with two opposite surfaces of the ingot being rolled. The passes 11 and 12 are used in rolling the partly reduced ingots into the smaller sizes of billets. The passes 9 and 10 are employed in rolling the partly rolled ingots into larger billets and blooms, and into some sizes of slabs, and the pass 8 is used in reducing the ingot, and in making slabs, (a product in which the width is substantially greater than its thickness). f

The passes 6 and 7, or the first two passes in the rolls are Gothic passes, in which each side surface 15 and 16, 17 and 18 is at an angle to the axial centers of the rolls. In this way each of the four sides of the ingot is su ported by the surfaces forming the Gothic passes 6 and 7 and all four sides are simultaneously acted upon by the rolls, in the early reducing operations while the cast ingot is first being compressed or reduced in cross section and elongated.

The manner of applying the rolling pres- .zontal dimension or width, adjacent to an angle of and 20, which extend horizontally in the first e of clearmills of the type the adjustable roll. In the upon sure to the ingots in reducing ingots by the methods heretofore used is illustrated in Figs. 2 and 3 and the manner of such application in accordance with my invention-is shown by Figs. 4 and 5 and in Fig. 1.

As is shown in Fig. 2 an ingot having the cross sectional contour and area of full outline A is reduced in area and its cross .section changed to thatof dotted outline B, by applying rolling pressure on two opposite sides 19 and 20, of 'the'ingot. The ingot is thereby reduced in its vertical dimension or thickness and somewhat increased in its boil? t e corners or junction of the sides 19 and 20 with the other two opposite sides 21 and 22. The ingot is then generally turned through 90 degrees to bring into vertical planes. The ingot is then the rolls in the pass full outline to the P againpassed through and reduced from the dotted outline C of Fig. 3. a

The direction of application of the rolling pressure and that in which the metal is compressed in the Gothic passes 6 and 7, is indicated by the arrows in Figs.

In rolling ingots by my improved method, the heated ingot is caused to enter the Gothic pass 6 with two diagonally opposite corners in a plane parallel with the longitudinal, or horizontal axes of the rolls, and the other two diagonally opposite corners thereof in a vertical plane perpendicular to the axes of the rolls. The rolls are then adjusted toward each other and the ingot is again passed 6 to further reduce it in cross section. The corners extending in a horizontal plane in the second pass 7 are those which were in a vertical lane in the first pass 6. One or more passes will be 'ven the ingot in the pass 6, the ingot being turned 90 degrees after each pass, to change the diagonally opposite corners in a vertical plane in one pass to a position in a horizontal plane in the succeeding pass. The smaller Gothic pass 7 is then employed to further reduce the cross section of the ingot being turned after each pass in the manner heretofore described.

Instead of turning the ingot through an angle of 90 degrees after each pass as has been described, two or more passes may be given the ingot between each turningoperation. s

The number of times the ingot is caused to travel through the pass 7 will depend the size of the ingot and the relative size of'the billet or bloom or other product into which the ingot is to b By reference to Figs. arrows indicate the direction of flow of the metal and the direction of the resultant of the application of the rolling pressure in my improved method, it will be seen that the the sides 19' e 4 and 5, in which the.

roiling pressure is applied to and the metal is simultaneously compressed upon all four sides of the ingot.

After the ingot is reduced to the desired extent in the pass 7 it is subjected to further reducing operations in the other passes 8, 9, etc., of the blooming mill, the number of passes depending upon the product to be made. and this portion of the rolling operation being carried out in the ordinary and well known manner.

The advantages of my invention, which will be appreciated by those skilled in the art, arise from the use of Gothic passes in the first reducing steps of the ingot. The use of the Gothic form of pass enables the ingot to be reduced simultaneously on all four sides thereof, and causes displacement of the metal from each side inwardly toward the center of the ingot.

B y supporting the ingot on each side during the initial reducing operations, stretching and cracking of the ingot during the early reduction thereof is entirely avoided and prevented and the amount of reduction in each of the early passes can be materially increased.

My invention is adapted for use with three-high blooming mills having passes which are of fixed size, this type of mill preferably being employed in rolling a fixed size of bloom from a fixed size of ingot, as well as the two-high type of mill which has been described, and which is used in cases where a fixed size of ingot is rolled into a variety of products or a. product such as a bloom or billet of a variety of sizes.

Modifications in the construction of the mills and in the arrangement of the roll passes may be made. Mills of other types may be used. But one Gothic pass may be employed, instead of two, as shown, or the number may be increased. The number of passes in the rolls may be changed, and other changes may be made without departing from my in ention as defined in the appended claims.

I claim- 1. The method of working ingots which consists in initially reducing the cast ingot by simultaneously displacing the metal of the cast ingot from each side toward the axial center of the ingot preliminary to later reductions in area and changes in cross section; substantially as described.

2. The method of rolling ingots which consists in initially reducing the cast ingot in at least one Gothic pass to thereby simul-- taneously displace the metal of the cast ingot from each side toward the axial center of the ingot preliminary to later reductions in area and changes in cross section; substantially as described. 7

3. The method of rolling ingots which consists in initially reducing the cast ingot in a series of Gothic passes to thereby simultaneously displace the metal of the cast ingot from each side towardthe axial center of the ingot preliminary to later reductions in area and changes in cross section; substantially as described.

In testimony whereof, I have hereunto set my hand.

TAYLOR ALLDERDICE. lVitnesses ANNA R. BEA'ITY, F.E. BROUN.

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