JPS62286609A - Method of transversely rolling seamless bored blank pipe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention 3 Detailed Description of the Invention The present invention is a method in which a perforated raw pipe is roughly rolled by a mandrel bar existing in the longitudinal hole or finish rolled by a mandrel bar on the exit side. The present invention relates to a method for cross-rolling seamless perforated blank tubes.

An example of such a horizontal rolling method is an inclined rolling mill.

It is carried out on rolling lines commonly known under the names of Ansel mill, Deitz/Yamil, Trans/<-lumil, Cone tilt mill, etc.

In such a rolling method, the mandrel bar is inserted, for example, into a longitudinal hole in the hollow material, or is present in the blank tube from the time of perforation. The hollow material is pushed axially together with the mandrel bar into the caliber opening formed by the rolls, discs and guide elements, after which the mandrel bar is held axially in its rear end and the hollow material is inserted into the perforated blank tube. At this time, it is passed through the caliber opening and roughly rolled by a mandrel bar.

A known rolling method of this type (U.S. Patent Publication No. 20063
36), the mandrel bar and the hollow material into which it is pushed are rotated about a common longitudinal axis.

Moreover, this rotation is controlled by the mandrel bar through a clutch mechanism.
This is done by a motor connected to the mandrel bar at its rear end opposite to the roll. The purpose of this is to reduce the acceleration that occurs when a non-rotating hollow member is inserted into the caliber opening with the mandrel bar present therein and captured by the rolls driven there. That is, in the horizontal rolling method, the material to be rolled including the mandrel bar rotates, and the above-mentioned acceleration from a stopped state becomes so severe that significant rolling irregularities occur. However, if the roll captures a hollow material, this hollow material rotates at a rotational speed determined by the roll.

In the known method, this is ensured by a freewheel clutch between the mandrel bar and the motor, which can be shut off during the actual transverse rolling. Even if the motors are rotating together at their working speed,
In the known method, this rotational speed is less than the rotational speed of the mandrel bar or the hollow member, so that the mandrel bar and the hollow member are not driven by a motor, but rather by rolls.

The method described above and other comparable methods for transversely rolling a seamless perforated blank tube have the disadvantage of so-called bulge formation. Viewed in cross section, the material to be rolled is rolled between the working surface of the roll and the outer surface of the mandrel bar, the wall thickness of the material being rolled being reduced. In this case, the mandrel bar acts as a counterroll to the driven roll. However, since these rolls are not driven in the known manner, these rolls are driven by the driven rolls through the rolled material, and the rotational moment is therefore transmitted from the driven rolls through the rolled material. Performed on a mandrel bar which is compared to a play roll. That is, the rolling operation to be performed by the mandrel bar is performed through the material to be rolled.

As a result, the neutral point moves in the circumferential direction of the material to be rolled, resulting in a bag-like separation of the inner surface of the material to be rolled from the jacket surface of the mandrel bar. In this case, the rolled material resists in the area of the roll nip.

This phenomenon is particularly noticeable when the material to be rolled has a slightly thick wall compared to its diameter and when rolling is performed with a large reduction in area. Moreover, this phenomenon occurs particularly in the region of the rear end part of the rolled material, since there there are still very thick hollow spaces that have not yet been rolled during the rolling process and are therefore still very thick-walled. Due to the lack of support by the rear part of the material, the conditions for drawing through the caliber opening are no longer guaranteed.The material to be rolled is often placed in the nip between the rolls, i.e. between adjacent rolls. It is pushed so far that it gets stuck in the free airspace of the roll cabinet or in the gaps between the guide members provided, and ends up becoming immobile and stuck between them.

To deal with this problem, attempts have been made to roll the end of the perforated tube to a relatively larger wall thickness by separating the rolls or by pulling out the mandrel bar (U.S. Pat. (See No. 590024).

However, this method has the significant disadvantage that the thick end portions have to be cut off and processed as crops, or additionally have to be subsequently stretched. Both processing techniques are economically disadvantageous and hinder the production process as a whole.

The underlying problem of the invention is to avoid the formation of bulges in the caliber opening to the greatest extent possible during the transverse rolling of seamless perforated blank tubes.

This object is achieved according to the invention by subjecting the perforated blank pipe to a predetermined controllable torque exerted by a mandrel roll during transverse rolling.

This rotational moment can be generated by a known mandrel bar drive mechanism.

However, in contrast to known constructions, in order to carry out the method according to the invention it is not necessary to provide a freewheel clutch between the mandrel bar and its drive mechanism, but rather a drive mechanism that generates a rotational moment that suppresses the formation of a bulge. All you have to do is control the mechanism. This rotational moment causes the mandrel bar to act like a normally driven roll,
By adjusting the mandrel bar drive mechanism appropriately,
The neutral point of the rolled material can be moved so that bulge formation is largely suppressed. The formation of a bulge can be eliminated at least to the extent that there is no longer any fear that the rolled material will stagnate in the inserted state. The wall thickness of the rolled material is maintained at a uniform value over its entire length, and a thinner wall thickness than before can be obtained.

In a further embodiment of the invention, the perforated blank tube is subjected to different high values of the mandrel bar torque in different regions of the length section during transverse rolling. As a result, when rolling the rear perforated part of the raw pipe, it is possible to
Therefore, the phenomenon of lack of support in the thick hollow material portion is compensated for.

It has been found to be advantageous to control the rotational moment exerted by the mandrel bar as a function of measuring the outside diameter of the bored blank tube from which it is extracted.

If the outer diameter changes beyond the permissible tolerance, the control circuit can also change the rotational moment exerted by the remand lever.Moreover, this change can be carried out until the bulge formation is normal again. This can be carried out in such a way that the outer diameter of the drilled blank pipe is controlled and brought back to the desired area.Furthermore, the rotational moment exerted by the mandrel bar can be determined by measuring the rotational moment at the mandrel bar. It can be controlled to a constant value. Fluctuations in the applied rotational moment may occur, for example, due to changes in the coefficient of friction between the mandrel bar and the drilled blank pipe due to differences in lubrication of the mandrel bar depending on the position. , this can be compensated for in the manner described above.

The invention will now be described in detail with reference to the embodiments illustrated in the accompanying drawings.

FIG. 1 shows three rolls 1, 2 and 3 surrounding a mandrel bar 4, partially and in section. Since the mandrel bar 4 is pushed into the hollow material to be rolled into a perforated blank pipe, the material to be rolled 5 exists between the mandrel bar 4 and the rolls 1 to 3. Rolled material 5
It can be clearly seen that they are spaced apart from the surface of the mandrel bar 4 in the region of the roll nip indicated by reference numeral 6 and form a bulge 7 in each case. However, in FIG. 1, the bulge is shown enlarged in order to clarify what is meant by the formation of the bulge. The present invention almost completely eliminates the formation of bulges, but even where this is not possible, it is minimized.

In FIG. 2, rolls 2 and 3 are visible, but the underlying roll 1 is not shown. A known roll drive mechanism is also omitted. The hollow material 9 is inserted into the mandrel bar which is drawn out in the rolling axis via the transverse feeding means 8.
Reach just before 4. A mandrel bar 4 and a shaft 4a connected to extend the mandrel bar are axially movable within a guide 11 by a motor 10.

Moreover, this movement is carried out together with a mandrel bar pusher 12 in which a rotary drive mechanism for the shirt 4a and therefore also for the mandrel bar 4 is incorporated. 3. FIG. 1 shows the rolling line according to FIG. 2, in which the mandrel bar 4 and the shaft 4a are shown in a forwardly pushed state. Since the hollow material 9 has already been sufficiently rolled, the perforated blank tube 3 protrudes from the roll stand on the exit side. The mandrel bar 4 likewise projects somewhat from the roll stand on the exit side. The mandrel bar is held in the hollow position and is pulled back to the position shown in FIG. 2 after the rolling process is completed.

4 to 6 illustrate a pusher 12 having a built-in rotary drive mechanism. The casing 14 of the bushing 12 is connected to the motor 10 (second
and FIG. 3), it is slidably driven in the axial direction via a lug 15 which is driven via a pinion (not shown). A shaft 4a forming an extension of the mandrel bar 4 is axially fixed in the casing 14 of the bushing 12, but rotatably supported. In particular, the two motors 16 which are actuated hydraulically (by way of hydraulic pressure) each drive two pinions 18 via one positively rotating launcher 17.
These pinions together drive the gear 19,
The rotational motion of these gears is directly transmitted to the mandrel bar 4 via the shaft 4a.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the caliber opening of the three-roll inclined rolling line. FIG. 2 is a plan view of the inclined rolling line with the mandrel bar driven in front of the rolls. FIG. 3 is a plan view of the inclined rolling line showing the mandrel bar in a driven state during the rolling process. 4 to 6 are front and side views, partially in section, of the mandrel bar drive mechanism. The code in the figure is. 1.2.3・10-ru 4...Mandrel bar 5...To be rolled 6...Roll gap 7...Bulging part 8...Transverse feeding means

Claims (1)

[Claims] 1. Seamless perforation in which the perforated raw pipe is roughly rolled with a mandrel bar existing in the longitudinal hole, or finish rolled with a mandrel bar existing on the exit side. A method for transverse rolling a seamless perforated blank pipe, characterized in that the perforated blank pipe is loaded with a predetermined and controllable rotational moment exerted by a mandrel bar during the transverse rolling. A method for horizontally rolling raw pipes. 2. Horizontal rolling of the seamless perforated blank pipe according to claim 1, in which the perforated blank pipe is loaded with mandrel bar rotation moments of different high values in the regions of different length sections during horizontal rolling. Method for rolling. 3. The seamless perforated raw pipe according to claim 1 or 2, in which the rotational moment exerted by the mandrel bar is controlled depending on the outer diameter measurement of the perforated raw pipe from which it is extracted. method for horizontal rolling. 4. Laterally rolling the seamless perforated blank pipe according to claim 1, in which the rotational moment exerted by the mandrel bar is controlled to a constant value depending on the rotational moment measurement at the mandrel bar. method for.