US2126509A - Tube rolling mill - Google Patents

Description

f Aug. 9, 1938. J. SEVERIN TUBE ROLLING MILL Filed Nov. sa, 1954 2 Sheets-Shea?J 1 f f Aug. 9, 1938.

J. SEVERIN Y TUBE ROLLING MILL Filed Nov. 9, 1934 2 Sheets-Sheet 2 Patented Aug. 9, 1938 UNITED STATES 2,126,509 'rUnEaoLLma Mns.

,me Severin, Maximin-num, omar, animar to Deutsche Bhrenwerke Aktiengesellschaft,

` Dusseldorf, Germany Application November 9, 1934, Serial No. 752,281 ln Germany November 25, l1933 s claims.

It is known to producetubes from hollow billets by stretching the billets-chiefly in the axial direction-by means of rolls the axes of which are at an angle to the axis of the hollow billet and whose path of travel on Vthe outer and inner faces of the hollow billet is 'of helical form; the rolls of the set of rolls around the periphery of the hollow billet are successively profiled in such l manner that each succeeding vroller further treats the section'of hollow billet already treated by thek preceding roll. In these processes the outer rolls alone effect the shaping, while, in the interior of the block, a mandrel or smooth roll serves as a support, or alternatively rolls on the inside take part in the shaping operation o perform it alone, while the outer rolls act as a smooth support.

The various kinds of shaping which are carried out by the profiled rolls differ in two principal respects. In one group the profiled rollers veiect an operation known from the time of forging by the term reduction by lowering" in which grooves are pressed into the billet by the first pair of rolls, so that a part of lthe blank is reduced ln diameter vtowards one end of the hollow billet; the part in question being widened smoothly towards the end .by shoulders on the succeeding rolls which at the same time spread the metal while sometimes making deeper the groove which has been formed in the metal by the rst pair of rolls. In the second method the hollow billet is shaped by rolls profiled conieallyJl or smoothly or formed pointed ln steps, in a manner corresponding to a drawing operation. In the known processes the material being rolled is passed into the rolling mill on one side--the "entry" side-until it isV gripped by the rolls and then driven through the rolling mill by them. The blank leaves the rolling mill on the 49 discharge side, and if it is to be passed through the rolling mill a second time, it must again be carried back to the entry side before it can again pass through the rolling mill. This conveying of the billet from the discharge side to the entry 45 side is attended with diiiiculties and disadvan- `tages. The rolling mills employed for carrying out the processes hereinbefore referred to are usually provided with a ring-shaped roll frame which carries the outer rolls that are driven by 5o spindles from a gear roll frame whose axis lies in alignment with the axis of the roll frame. These spindles hinder the blank from being returned to such a degree that the heated blank cools considerably, which is la distinct disad-v 55 vantage in connection 4with thesubsequent roll- (Cl. 8F13) ing operation. Even when the rolls in the annular roll frame are not driven by spindles from the gear roll frame disposed on the same'axis, but laterally, considerable difliculties are encountered in the returning of the rolled material; 5 these difliculties are caused by the operatives' working on the rolling mill being obliged to reset the inside and outside rolls required for `the next passage after each passage through the mill. 10

Methods of producing tubes are known in which after each passage of the material being rolled through ,the rolling mill itself there is a further passing through of the material in the opposite direction; thus :lor example a method 15 is known in which the rolls of an inclined rolling mill as ordinarily employed for piercing solid cylindrical billets are so provided that certain of the rolls cause the piercing while the ma,- terial is passing through the rolling mill in one 20 direction while during the reverse movement, after the change of direction of the rolls, the remaining rolls cause the material which has been pierced while travelling in the original direction to be stretched, whereby the walls of the tube 25 produced are reduced in thickness and its length increased. Another known process, which makes useV of the known conical roll discs for the intended shaping of the material being rolled effects the to-and-fro movement of the rolled material 30 by using guides'which are so provided that in one case the material being rolled is guided to the discs above their centre of rotation while in the other case the feed is effected below the centre of rotation of the s which effect the 35 change of shape, and thus the direction of rolling is reversed without the reversal of the direction of rotation of the shape-changing discs.

These known methods for changing the direction of rolling cannot beemployed for the 40 processes hereinbefore described in the second paragraph, because in these processes the returning of the material being rolled` cannot be, made possible solely by`reason of the fact that the .rolling mill is run in the opposite direction. For

in these processes herelnbefore referred to the rolls are so profiled that the rolls whichfflrst come into action during the hrst passage of the material through the rolling mill grip the work by their shape-changing parts, the hollow blankV I having its original thickness, while the shape? changing parts of the other rolls are unable to function correctly until the'preceding rolls have f already carried out part of the shape-changing operation.` During the reverse movement -of such 56 a rolling mill the shape-changing parts of the rolls that were last operating during the forward ron the billet in been directions through rolls with two passes, which correspond to the sequence in the forward and rearward movements, the rolls whose first passes are operative in the forward movement being rocked after the forward movement, through such an angle that the second passes provided for the return movement come into the working position. The reduction in the thickness of the material being rolled, which has been obtained as the result of the rst passage through the rolls must be taken into account when determining the calibration of the return movement. The two passes of the outer and inner rolls, or only of the outer rollers or only of the inner rolls can be set singly, it being possible for each of the rolls with two passes to be replaced by two rolls each adapted to be proilled individually. l Apparatus according to the invention is diagrammatically illustrated by way of example in the .accompanying drawings. Y

Figure 1 illustrates in longitudinal section a `roller mill with inner and outer rollswhich are capable of being rocked out of alignment.

Figure 2 illustrates asimilar rolling mill withl inner rolls only which are capable of being thus moved.

Figure 3 illustrates a similar rolling mill with outer rolls only which are capable of being thus moved.

Figure 4 illustrates a complete tube rolling mill, with setting devices for rocking rolls B.

Figure 5 illustrates the mandrel head of a rolling mill provided with pairs of rolls each separately calibrated.

Each of the Figures 1 to 3 of the drawings illustrate a rolling mill provided with a circular series of six pairs of rolls with the shaping parts' operating on single helical lines when rotating in the clock-wise direction. Where it is advisable,

for the sake of cleamess, only to show in the drawings two pairs of rolls, the remaining rolls are indicated in the-following description by ref,- erence letters that do not appear on the drawings. Thus,.outer rolls may bepresumed to vbe numbered B1', lBz, Ba, B4, Bs and Bs and of these list Bi and B4 are shown in the drawings and the inner rolls may similarly be considered to be numbored Ci, C2, Ca, C4. Cs, Cs and 0f these Ci and C4 are shown in the drawings. The material A enters the iirst pass in the direction indicated by the full line arrow. The parts of the rolls which operate on the entry side are numbered Krl K2, K1 K4, Ks and K4, of which K1 and K4 only are shown in they drawings, the pass K1 functioning during the tlrst passage of the material while the pass Ks is operative last of all. In addition to these passes each roller is provided with passes Ki, Kz, K'a, K4, K's, and K'a, K': and Ka only being shown. K'1 being formed by the rolls which form the pass Ks in the direction of the original en try side and the pass K'a being-formed by the rolls which form the pass Ki in the direction of the original entry side. If during the `ilrst passage the material being rolled is rotated from that position which may be termed the original entry side in the clockwise direction, it must in the return movement be rotated from the original entry side in the anti-clockwise direction, that -is to say the material rotates in one direction in relation to the direction of passage of the tube through the mill. The direction of the return movement is indicated by dot-and-dash arrows.

In order to bring into use the passes Ki, K2, K1, K4, K5, Ks, or Ki, K'z, KJ, K'4, K's, Ks in the requisite manner and at the right time lfor the shaping operation the working rolls are provided to be capable of rocking that is to say the outer and inner rolls in Figure l only the inner rolls in Figure 2, and only the outer rolls in Figure 3. 'I'he rocking angle here corresponds to the depth of the depression. The pivotal points about which the rolls are rocked in the examples illustrated in Figures l to 3 are outside the rolls on the original entry side. They may, however, be otherwise selected, that is to say they may be inside the rolls themselves or at any other position according to the change of shape desired or type of rolling mill employed. An example o1' this is illustrated in Figure 4.

In the constructions shown in Figures 2 and 3, in which only the inner or the outer rolls vare rocked, the material being rolled moves the ilrst time it passes through-that is in the direction indicated by the full line arrow as in the example according to Figure l freely through the second pass without contacting with it. In the return movement of the material from the original discharge side inthe direction indicated by the arrow in dot-and-dash lines, the passes K1 etc.

formed by the rolls and their non-rocking counter rolls become operative after the rocking of the inner or outer rolls, by reason of the fact that the rolls to be rocked are rocked not only to the extent indicated in Figure 1 but beyond this to such a degree that an increase or reduction is obtained in the diameter of the material by reason of the coning or entry of the inner and outer rolls, as will be seen from the dot-and-dash lines at F. Figure 2 illustrates a different roll pass from that shown in Figures 1 and 3.

'I'he inner rolls are secured to the mandrel E in knownmanner by means of a roll head D. As will be seen from Figure 4. the outer rolls B are mounted to rock in bearings H and in simllar manner the inner rolls C are mounted in bearings J. 'Ihe bearings for the inner rolls are capable oi' rocking by reason of their spherical supporting base. 'I'he rocking movement as such can be obtained by a very large number of known machine elements.

Figure rillustrates a modified construction of the roll head D which is provided with a support for the inner rolls C at the middle position, each of the inner rolls being divided into two rollers each having a separate pass. This arrangement has the advantage that rolls or roll spindles of small diameter may be employed just as might be possible with undivided rolls on account of their length.

I claim:

1. A rolling mill for producing tubes from hollow billets by stretching, particularly in the axial direction, and comprising several sets of inner and outer rolls, the inner and outer units of which have their axes lying inclined to the path of travel of the hollow billet and are adapted to operate respectively upon the outer surface and the inner surface of the hollow billet by grooving the material on helical lines and widening the groove, the rolls of the several sets of rolls which successively operate upon the billet being formed with passes related in such manner that every succeeding roll set acts upon the part of the hollow billet which has already been acted upon by the preceding roll set, and Ineens whereby the mill is adapted for rolling the hollow billet in both directions of travel through it, the said means consisting of passes provided upon the units of the several sets of rolls, certain of which passes are eiective in one direction of travel of the hollow billet and certain of which passes' are effective in the reverse direction oi travel oi the hollow billet, the passes for the reverse direction of travel being formed and positioned to continue the working of the billet carried out by the passes that are operative in the forward direction oi travel of the billet and the rolls of each set of rolls being rotated in the reverse direction of rotation for the return direction of travel of the billet.

2. A rolling mill according to clnlm 1, having, included in the sets oi' rolls, rolls hoi/ing passes which are operative respectively in the two direc tions of travel of the hollow billet end ineens whereby the axes of the rolls may be roclredto bring the pass required into operative position.

3. A rolling mill according to c l, wherein einem@ sets oi rolls include sets of which one roll is of fixed position and is of a form such that the required pass comes into operation according tg the direction of travel of the hollow billet, and a second roll is adapted to be adjusted to render the two passes of the said rolls alternatively operative, the said rolls being provided with means for eilecting the required adjustment.

. i. A rolling mill according to claim 1,v having. included in the sets of rolls a set oi.` rolls which are operative for the one direction of travel oi the hollow billet and other sets of rolls which are operative for the return direction oi travel of the hollow billet.

5. A rolling,r mill according to claim i, wherein the sets of rolls are provided to include sets oiv rolls of which one roll is formed with passes which are alternatively operative according to the direction of travel oi' the hollow billet and other rolls which are alternatively operative accoi-ding to the direction ofv trnvei oifthe hollow billet eo-operate respectively with the posses oi the st roll.

JOSE SEVFRN.

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