US2341910A - Method of and machine for preblooming ingots - Google Patents

Description

Feb. 15, 1944; 's E. DIESCHER 4 7 I METHOD OF AND MACHINE FOR PREBLOOMING INGOTS I I Filed July 12, 1940 5 Sheets-Sheet 1 wmlassss. N INYENTOR.

- M (5 M/LM '44. ATTORNEYS.

Feb. 15, 1944:. 5', sc 2,341,910

METHOD OF AND MACHINE FOR PREBLOOMING INGOTS Filed July 12, 1940 5 Sheets-Sheet 2 WITNESSES. J I ITOR. WW. I BY am flaw, fib M 4., ATTORNEYS.

Feb. 15, 1944. DIESCHER 2,341,910

' METHOD OF AND MACHINE FOR PREBLOOMING INGOTS Filed July 12, 1940 5 Sheets-Sheet 3 WITNESSES. v INVENTOR.

flak/Mm. BY M i 7 (Wm, I

44; ATTORNEYS.

Feb. 15, 1944. s. E. DIESCHER METHOD OF AND MACHINE FOR PREBLOOMING INGOTS Filed Jur 12, 1940 5 Sheets-Sheet 4 WITNEJJEG.

15, 1944-, I s. E. DIESCHER 2,341,910

METHOD OF AND MACHINE FOR PREBLOOMINGINGOTS Filed July 12, 1940 5 Sheets-Sheet 5 WT P INVENTOR.

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BY Q) 60 'LO'WW o'vrr M Patented at. 15, 1944 UNITED STATES Search Room PATENT OFFICE METHOD OF AND MACHINE FOR PREBLOOMING INGOTS Samuel E. Diesclier, Pittsburgh, Pa.

Application July 12, 1940, Serial No. 345,154

16 Claims.

This invention has to do with treating steel ingots before they are reduced on blooming mills, the apparatus used for this treatment being referred to herein as a pre-bloomer.

Such ingots as are bloomed are always tapered longitudinally; that is, the cross section at one end is definitely less in area than at the other. The degrees of taper of ingots to be reduced in blooming mills vary over a considerable range, depending upon different mold designs and practices in teeming of the ingots. When ingots are reduced in a blooming mill the common practice is to subject them in their first passes to such an amount of reduction as quickly to convert their forms from pyramidal frusta to prismatic shapes, because otherwise inconvenience in the manipulating of the ingots on the blooming mill tables and accompanying delay in the procedure of blooming arise. The large initial reductions that are thus brought about often create surface cracks in the ingot of a character that can not be healed, and therefore, in many instances, require to be chipped out or otherwise removed at later stages in the processing of the steel, the performance of which conditioning is very expensive. To avoid some of such conditioning, in some practices it is customary to baby the ingot in its initial passes through the blooming mill, by which is meant to operate the mill slowly and with as small reductions as feasible. The delays in doing this not only add substantially to the cost of manufacture, but also often create at the blooming stage of the series of procedures involved in steel manufacturing a bottleneck that effects adversely the output of combined procedures.

The surfaces of ingots are inherently weak and are very likely to acquire cracks under any but the most cautious initial procedures, but if cautiously worked these surfaces become stronger and therefore more resistant to the effects of rolling in the blooming mill. Thus it seems clear that prior to any blooming mill deformation, which because of the great amount of displacement involved must necessarily be drastic, other means are badly needed for conditioning the ingot prior to blooming, the providing of which means is the purpose of this invention.

The foregoing considerations apply to all forms of tapered ingots, whether they be round, square or slab shape in transverse section. Because it is becoming known that many steel from steel cast into round, as compared to rectangular cross-section, ingots, the use of such round ingots is now being strongly advocated. Like ingots of other shapes, they also are tapered from end to end. In reducing round ingots in a blooming mill it is necessary in the initial passes, in addition to removing their tapers, to change them to forms that are substantially square or rectangular in cross section.

The difficulties involved in the manipulation of round ingots to effect properly their initial blooming passes are such that much more time is required to bloom them than to bloom rectangular or square ingots.

The object of this inventtion is to provide a method of and apparatus for so treating or preblooming tapered ingots of any cross-sectional shape that their surfaces will not suffer the impairments which attend such ingots when given the customary initial passes through a blooming mill, that they may be bloomed more rapidly, and that round ingots may be bloomed as rapidly as are those which are square or rectangular in'cross section.

The invention is illustrated in, and may best be explained with reference to, the accompanying drawings, of which Fig. 1 is a plan view, partly in section, of a machine for pro-blooming tapered ingots, in the operation of which the method herein disclosed may be practiced;

0 similar to Fig. 6 showing rolls formed to act upon a rectangular ingot which is elongate in cross section; Fig. 8 a view corresponding to Fig. 5 showing rolls acting upon an ingot that is generally circular in cross section; and Fig. 9 a

diagrammatic view illustrating successive stages in the pre-blooming of an ingot according to this invention.

In the practice of my invention a solid tapered steel ingot is repeatedly moved, preferably with its small end foremost, through a closed roll pass which is preferably formed by two pairs of oppositely disposed rolls, one of which pair is slightly in advance of the other so that the outer ends of one pair of roll faces products have better characteristics if made will overlap the outer ends of the other pair of roll faces in such a manner that a fully closed pass within all four faces is presented. Assuming the ingot to be substantially square in cross section, in the first pass through the rolls the taper of a portion of the larger end of the ingot is removed by the reduction of such portion to the contour of the pass. The ingot is then similarly moved through the roll pass to remove its taper from an adjoining section and to further reduce the portion of the ingot previously moved through the pass. This operation is repeated to reduce progressively longer lengths of the ingot until its taper is removed and it is of substantially uniform cross section from end to end. Preferably, the movements of the ingot are produced by pushing it upwardly through the roll pass to effect its successive reductions, and by lowering it between the rolls between successive reducing and taper-removing operations.

The same procedure is followed when a round tapered ingot is thus treated or pre-bloomed to simultaneously remove its taper and convert it into a form which is sufficiently rectangular in cross section to permit ready manipulation on the blooming mill tables. However, for th accomplishment of this dual result a greater number of passes may be required than for preblooming rectangular ingots.

The number of pre-blooming passes given an ingot depends in part on its original taper, it being understood that to avoid the forming of surface cracks and the enlargement of those originally existing it is desirable to effect a relatively small reduction in each of the passes. of thi it is desirable to give ingots having large tapers more passes than those having small tapers. When an ingot is thus pre-bloomed it is rendered substantially uniform in cross section from end to end and may be reduced in a blooming mill without any delay in the initial passes and with a far better surface.

This method of treating ingots will be further explained in connection with the following description of the pre-bloomer illustrated in the drawings and by which the method may be practiced. Having reference first to Figs 1 and 2, a pre-blooming pass is formed between the opposed working faces of two pairs of rolls I, 2 and 3, 4, each of which is supported by a housing 5. the construction of which will presently be explained. As shown in Figs. 2 and 4, the movements of ingots upwardly through the pass formed by these rolls are preferably effected by a ram I mounted for vertical movement in a hydraulic cylinder 8 to which pressure fluid may be fed and from which it may be discharged by a conduit 9 adapted to be connected to a source of pressure fluid supply. There may be several conduits 9, the number used depending upon the plunger speed desired. The upper end of the cylinder is encircled by and connected to a supporting member H which is mounted upon a foundation l2 and which is provided with a flange |3 that receives the lower ends of guide rods M. The upper ends of these rods are anchored in the lugs of bed plate IS, the latter forming'a cross as shown in Fig. l. The upper end of ram 7 is provided with a spider-like crosshead I! having bushed openings in its projections for slidably receiving guide rods |4. Attached to the top of the ram is a tall pedestal la, the upper end of which forms a base for supporting an ingot l9 as it is moved upwardly and downwardly through the roll pass.

In view Each roll is in the form of a ring rotatably mounted on a stationary shaft 2| carried by a vertically split housing 5 which is slidable toward and away from the roll pass in upright guide members 23 at the opposite sides of the underlying bed plate IS. The housing is adjusted toward the roll pass by a pair of parallel screws 24 the front ends of which engage sockets 26 attached to the outer end of the housing. Each screw is threaded through a nut 21 rigidly mounted in a pedestal 28 supported by th bed plate, and has a smooth rear portion splined in a worm gear 29 also carried by the pedestal. The two gear on each pedestal are driven by a worm 3| from an electric motor 32 supported at one side of the pedestal. Each stationary shaft 2| has on each end a gudgeon for crane sling seating in changing rolls.

While the movement of each housing away from the center line of the roll pass may be effected by screws 24, such movement is preferably accomplished by a pair of rods 33 pivotally connected to the housing below the screws. The outer ends of these rods are pivotally connected to a cross head 34 carried by the outer end of a plunger 36 slidably mounted in a fluid pressure cylinder 31 formed as a part of the pedestal. By moving the housing outwardly by fluid pressure in the cylinder as the screws are backed away from the pass, it becomes unnecessary to anchor the forward ends of the screws in the housin and thus eliminates a complicated connection. The pivotal connection of rods 33 to the plunger and housing takes care of any vertical misalignment due to wear of the housing slides. The principal function of the fluid pressure arrangement is to eliminate clearance between screws 24 and their seats 26, thereby eliminating back lash, or pounding, when rolls 3 and 4 and then rolls and 2 are brought into contact with the ingot.

In order to center each ingot on pedestal |8 before it is raised into the roll pass the first time, the opposite sides of the ingot are engaged by centering members 4| spaced equal distance from the center line of the pass toward which they are movable, as shown in Figs. 2 and 3. Preferably, each centering member is moved horizontally by a pair of rods 42 the outer ends'of which are connected to a block 43 that is slidably mounted between two stationary blocks 44 supported by the overlying bed plate. Each of the stationary blocks is provided with a fluid pressure cylinder 46, slidably mounted in which is a plunger 41 that is attached to the slidable block 43. When fluid pressure is introduced into one cylinder or the other, the slidable block moves rods 42 and the attached centering member 4| toward or away from the center line of the roll pass.

In pushing the lower end of the ingot up through the roll pass the base of elevating pedestal 8 rises so high that it strikes centering members 4|. To prevent these members 4| from interfering with further upward movement of pedestal base l8, each member 4| is connected at its outer end to adjoining rods 42 by a pivot pin 48 which projects from the rods and into horizontal slots in a supporting member 49 suspended from the bottom of bed plate I6. Thus, when the rising pedestal base strikes centering members 4| it swings them upwardly out of the way. As pedestal l8 recedes on the downward stroke of ram 1, the centering members 4| return, by gravity, to guiding position. This uidshims between the frame and housing.

in: position of members an is controlled by lugs 50 at these outer ends which slidably bear against the bottoms of bed plates II.

To insure all of the centering members moving exactly in unison their movements may be controlled by controlling the pressure fluid supplied to cylinders 46 so that the same amount is operation is repeated as often as is-necessary by adjusting-the rolls successively to the..p'ositions indicated by the arcs II and It. the successive supplied to each. or, as is preferred, a gearing mechanism may be used that ties them together. Thus, the bottom of each slidable block I! is provided with rack teeth which register with a gear pivotally mounted on a shaft 52 below it; The various shafts are geared together by miter gears 53 at their. ends so that they all must turn together, and thus maintain the guiding faces of though, asshown in Fig. 'l, the pre-bloonier is the respectiveopposite members ti equidistant from the center line of the pass.

To aid in guiding the ingot into the roll pass a pair of guide members 58 (Fig. 2) ai'e disposed between the upp r pair or rolls i and 2 and centering members 4 I. Preferably, each guide memher is attached to the bottom of the adjacent first to remove its taper and-then to bring it sufficiently to a rectangular form to aflord easy housing 22 near its outer end and extends inwardly therefrom under roll I or 2 to the pass.

Any suitable means, such as an eccentric adjustment 51 (Fig. 3), can be used for adjusting the guide member toward and away from the pass independently of the roll above it. Such adjustments are for compensating for roll wear and ingots of various tapers. Two pairs of guides 58 are also mounted above the rolls to prevent the ingot from toppling over when in its uppermost position. These guides preferably are pivoted on horizontal axes in frames 59 mounted on the roll housings. The lower end of each guide slides on the underlying roll, and. the supporting frame is adjustable towardand away from the elongations of the ingot beingindicated by the lines u, u, u and a. It will be understood that r the other pairs of rolls, whichfor simplicity are not shown in Fig. 9. are adjusted similar to the rolls shown for each pass.

- The foregoing explanatlon'of the procedure applies particularly toingots which-are in cross section. The same procedure is "followed when rectangular ingots are .pre-bloo ned, al-

then equipped with rolls to and la wider faces than those ofrolls I and}. In "removing the' taper from and reducing the cross section of a roundingot, additional passes'are manipulation in the blooming mill operation to follow. The-position of the'two pairs of rollsat the beginning of the pre bI 'oming' of a circular ingot is shown in'Fig. 8. when an ingotolsny form is thus pro-bloomed, it may be either from the upper end of pedestal "onto a con,- veyor leading to a blooming mill, or,, if, desired. it may be returned to a soaking pit to give it .a wash heat. v

By pre-blooming ingots according to this invention, the'delay incident to .the babyingf ingot in a blooming mill is eliminated'andlieijlce i the time for blooming each ingot is materially reduced. While this is a substantial advantage. a more important advantage of m lnvention -re' sides. in the eliminationof the formationof surface cracks which frequently arise in thedniidrtl passes of an ingot through a blooming'r'nill,

roll pass independently or. the roll in any suitable manner, such as, for instance, by the use of M In the pre-blooming of an ingot by this apparatus, ram 1 is first moved upwardly to position the upper'end of pedestal ll above the portion of the pas formed by upper rolls l and 2,

all of the rolls being then in their spread-apart a position in' which a portion of the taper of the lower end of the ingot is removed by the upward movement of ram 1.

In Fig. 9 the positions of a pair of rolls relative to an ingot arev indicated diagrammatically for each of several passes of the ingot between the rolls. In the first pass the rolls are adjusted. as shown at the lower end of the ingot.v to re- ,move the taper from the p rtion of the ingot,

below a' horizontal plane indicated by the line ll. In such operation, the reduction of. the ingot results in its becoming but slightly elongated to an extent indicated by the dotted line ii. To avoid needless chilling of the ingot surface, the rolls may be adjusted outwardly, but regardless of this they are next adjusted towards the center line of the roll pass to the positions indicated by the arcs 63. When the ingot is again moved upwardly, its taper is removed between the horizontal planes 60 and I4, and below the plane indicated at 60 the ingofis further reduced. This The rolls ar then moved by also in the elimination of enlargements ofcrak's originally present on the surfaces of ingots. By

pushing the ingot through e closed pass in the manner of an extruding operation it is sary to make substantially large reductions in each pass, as maybe done in a blooming rolls of which are frequently so adiustedas to grip the small end of an. ns0t umoie t1ytb posi;

tively' feed the ingot through he rolls. As a re-v sult of. making small taper ellminating and in got-reducing reductions, not only is the surface of the metal not impaired. but the structure characteristics or the metal are improved as comparedyith products dependent upon effecting mill. Y

It will be. understood that the passes through the pre bloomer are shorter in length than-those through the bloomingmill to which prebloomed ingots are fed, and that for the successive passes of the progressively elongated ingot through the blooming an increased amount of time is required. To increasethe rate of production of the blooming mill, it may in some cases be advantageous to pre-bloom ingots to a greater extent than is required 'merelytoremov'e tap The amount of such additional reduction effected in the prg hlooni'e'rwilldepend upon the time required to do it as compared with that required for the subsequent blooming. By way of example, if normal ire-blooming" l half as much time as iln'al blooming. additional reductions may be made in. the pre-bloomer with the result that less time would be required in final blooming. Thenet result of this will be to' increase the rate of production of bloomed ingots.

The type of rolls described herein lend themselves to bflg made of diameters larger than the entire reduction in a blooming.

normally used in blooming mills. This provides flatter arcs of contact with the ingot surfaces and thus tends not only better to compact the surfaces thereof but also to offer less resistance against the ingot being forced through the pass. The concave working faces shown on the rolls provide for easing the strain at the corners of the ingot cross-section and thus reduce any tende'ncy for cracks to form at the corners. The rolls, being mounted on anti-friction hearings, will tend to drift after losing contact with the ingot. This exposes new surfaces of the rolls to the work, thus tending to avoid local heating and also to distribute wear and thus to lengthen roll life. Also shafts 2| may occasionally be shifted to new circumferential positions, thus distributing irregular wear under localized pressures at anti-friction bearings and at end supports, thereby adding to the life of the bearings.

Also it may in some cases be desired to prebloom ingots with their butt ends up. 'This could readily be accomplished by the method described.

According to the provisions of the patent statutes, I have explained the principle and mode of operation of my invention and have illustrated and described novel apparatus upon which it maybe practiced. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described and with apparatus other than that herein illustrated.

I claim:

1. The method of treating a solid tapered steel ingot prior to blooming it, comprising periodically moving the ingot small end foremost through a closed pass to roll it, and decreasing ,the area of the pass between each rolling operation to reduce progressively longer lengths of du'eed in progressively longer lengths substantially to uniform cross section from end to end.

8. The method of treating a solid tapered steel ingot prior to blooming it, comprising moving the ingot through a substantially rectangular closed pass nearly as large as the large end of the ingot. and formed by two pairs of oppositely disposed rolls positioned one pair in advance of the other, periodically adjusting the rolls of .each pair thereof towards the center line 'of their pass whereby 'todecrease the area thereof, and aftereach such adjustment of the pass moving the ingot through it to reduce progressively longer lengths of the ingot until it is of substantially uniform cross section from end.

ingot prior to blooming it, comprising pushing the'ingot with its smaller end foremost through a closed pass and therebyreducing a portionof the larger end of the ingot, and repeating this operation through the same pass reduced in area; between each operation until the ingot is reduced substantially to uniform cross section from end to end.

3. The method of treating a solid tapered steel ingot, in a closed roll pass comprising pushing the ingot upwardly with its smaller end uppermost through said pass to thereby reduce only the larger portion of the ingot, and repeating this operation through the same roll pass .reduced in area between each operation until the ingot is rolled throughout its length and is reduced substantially to uniform cross section from end to end.

4. The method of treating a solid tapered steel ingot prior to blooming it, comprising periodically movingthe ingot through a closed pass inivtially nearly as large as thelarge end of said ingot, and decreasing the area of the pass between each rolling operation to reduce progressively longer lengths of the ingot until it is of substantially uniform cross section from end to end.

5. The method of treating a solid tapered steel ingot prior to blooming it, comprising pu'shing the ingot upwardly through a'closed pass initially nearly as large as the large end of said ingot, the smaller end of the ingot being uppermost, then lowering the ingot, reducing thesize v of saidpass, andrepeating said raising and lowering and pass reduction until the ingot is re- 8. A machine for pre-blooming tapered ingots, comprising two pairs of oppomtely disposed rolls positioned one pair in advance of the other to form a substantially rectangular pass whose center line extends vertically, means for adjusting' the rolls towards and from the center line of their pass, and means for repeatedly elevating a taperedingot through the pass formed by the rolls to reduce progressively longer lengths of the ingot until it is of substantially uniform cross section from end to end.

9. A machine for pre-.-b1ooming tapered ingots, comprising two pairs of oppositely disposed rolls positioned one pair in advance of the other to form a substantially rectangular pass whose center line extends vertically, means for adjusting the roll towards the center line of the roll pass, a pedestal for supporting a tapered ingot in upright position in the line of pass, fluid pressure means for elevating said pedestal to force a tapered ingot between the rolls whereby to removeits taper, guide members for guiding the ingot in its vertical travel, and means for retracting said rolls and guide members. suiilciently to permit said pedestal and fluid pressure means to be lifted up between the rolls and the ingot removed.

10. A machine for pre-blooming tapered ingots, comprising two pairs of oppositely disposed rolls positioned one pair in advance of the other to form a substantially rectangular pass, screw means for adjustingv the rolls towards the-center line of their pass, fluid pressure means for retracting said rolls, and means for repeatedly moving a tapered ingot through the pass formed by the rolls to reduce. progressively longer lengths of the ingot until it is of substantially uniform cross section from end to end.

11 A machine-for pre-blooming tapered ingots; comprising two pairs of 'oppositely disposed 7 rolls positioned one pair in advance of the other ings and rolls inwardly towards the center line of the roll pass, a fluid pressure cylinder spaced outwardly from each housing, a plunger slidably mounted in the outer end of each cylinder, a link pivotally connected toThe outer end of each plunger and the adjacent housing whereby to retract the housing, and means for repeatedly moving a tapered ingot through the pass formed gots, comprising two pairs of oppositely disposed rolls positioned one pair in advance of the other to form a substantially rectangular pass whose center line extends vertically, means for adjusting the rolls towards and from the center line of their pass, means to! repeatedly elevating a ta ered ingot through the pass formed by the rollsv to reduce progressively longer lengths of the ingot until it is of substantially uniform cross section from end to end, means between said rolls and elevating means for guiding the ingot into the roll pass, said guiding means being adjustable in unison with said rolls toward and away from the center line of the pass, and means for adjusting said guiding means relativeto the pass to compensate for wear of the rolls.

13. A machine for ,pre-blooming tapered ingots, comprising two pairs of oppositely disposed.

rolls positioned one pair in advance of the other to form a substantially rectangular pass whose center line extends vertically, means for adjusting the rolls towards and from the center line of their pass, means for repeatedly elevating a tapered ingot'through the pass formed by the rolls to reduce progressively longer lengths of the ingot until it is of substantially uniform cross section from end to end, and means for centering an ingot on said elevating means prior to being elevated.

' 14. A machine for pro-blooming tapered ingots, comprising-two pairs of oppositely disposed mils positioned one pair in advance of the other to form a substantially rectangularpass whose center line extends vertically, means for adjustgots, comprising two pairs 01" oppositely disposed rolls positioned one pair in advance oi the other to form a substantially rectangular pass whose center line extends vertically, means for adjusting the rolls towards and from the center line of their pass, means for repeatedly elevating a tapered ingot through the pass formed by the rolls to reduce progressively longer lengths of the ingot until it is of substantially uniform cross section from end to end, and lateralLv movable members for eng slns the sides of an ingot to center it on said elevating means, the outer end of each of said members being pivotally mounted on a horizontal axis whereby it is movable upwardly when struck by the rising elevating means.

l6. A machine for pre-blooming tapered ingots, comprising two pairs of oppositely disposed rolls positioned one pair in advance of the other to form a substantially rectangular pass whose center-line extends vertically, means for adjusting the rolls'towards and from the center line of their pass, means for repeatedly elevating a tapered ingot through the pass formed by the rolls to reduce progressively longer lengths of the ingot until it is of substantially uniform cross section from end to end, laterally movable members for engaging the sides of an ingot to center it on said elevating means, a ij'luid pressure motor spaced outwardly from each of said members and connected thereto for actuating said members, and all of said motors being geared tosether for controlled movement in unison.

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