JPS6216807A - Method of laterally rolling seamless drilled 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 The present invention provides a seamless perforation method in which a perforated raw pipe is roughly rolled by a mandrel bar existing in the longitudinal hole or finished rolled by a mandrel bar on the exit side. The present invention relates to a method for horizontally rolling (Qθrwalzen) a blank pipe.

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

Atsel Mill, Deitssha Mill, Transvaal Mill,
This is carried out in a rolling line commonly known under the name of a cone inclined rolling mill or the like.

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 the drilling process. The hollow material is pushed together with the mandrel bar in the axial direction into the caliber opening formed by the roll, disc and guide member, after which the mandrel bar is fixed in the axial direction at 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 (US Patent Publication No. 2006
No. 556), the right mandrel bar and the hollow member 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 this one-drel bar at the rear end portion on the opposite side of the roll. The purpose of this is to reduce the acceleration that occurs when the non-rotating hollow material, together with the mandrel bar located inside it, is inserted into the caliber opening and is captured by the rolls driven therein. 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 is not driven by a motor, but rather by a roll.

The above-mentioned method and other comparable methods for transverse rolling seamless perforated blank tubes involve the so-called bulge formation (
It has the disadvantage of "sackbildung". 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 to be 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. The mandrel bar is compared to an idle 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 of the material to be rolled moves in the local direction, 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.

When the material to be rolled has a small wall thickness compared to its diameter, and rolling is performed with a large reduction in area.

This phenomenon is particularly noticeable when Moreover, this phenomenon occurs particularly in the area of the rear end portion of the rolled material. This is because there, while the rolling process is progressing, there is a lack of support by the rear part of the hollow material, which has not yet been rolled and is therefore still very thick. In this case, the conditions for drawing through the caliber opening are no longer guaranteed and are in jeopardy. In this case, the material to be rolled often ends up in the roll nip K, that is to say in the free space between adjacent rolls, or in the roll cabinet and possibly between the guide elements provided, resulting in no movement. Can't take it and stays between them.

It pushes me so hard that I end up doing it.

To deal with this problem, attempts have been made to roll the end of the perforated blank tube to a relatively large wall thickness by separating the rolls or pulling out the mandrel bar (see US Patent Publication No. (See No. 590024).

However, this method has the significant disadvantage that the thick end sections have to be cut off and processed as crops, or additionally have to be subsequently stretched. The image processing step is economically disadvantageous and hinders the manufacturing process as a whole.

The underlying problem of the present invention is to avoid as much as possible the formation of bulges in the caliber opening during the transverse rolling of seamless perforated pipes.

This object is achieved according to the invention by loading the perforated blank tube with a predetermined controllable torque exerted by a mandrel bar during the transverse rolling operation.

This rotational moment can be generated by a mandrel bar drive mechanism which is known per se.

However, in contrast to known constructions, the method according to the invention does not require the provision of a freewheel clutch between the mandrel bar and its drive mechanism, in order to generate a rotational moment that suppresses the formation of the bulge. All that is needed is to control the drive mechanism. This rotational moment causes the mandrel bar to act like a normally driven roll,
By appropriately adjusting the mandrel bar drive mechanism,
The neutral point of the test roll 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 thick hollow parts 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 tolerances, it is also possible to change the rotational moment exerted by the mandrel bar by means of the control circuit. Moreover, this change can be carried out so that the formation of the bulge is again controlled to a normal level and the outer diameter of the perforated blank tube returns to the desired value range. Furthermore, the rotational moment exerted by the mandrel bar can be controlled to a constant value as a function of the measurement of the rotational moment at the mandrel bar. Fluctuations in the applied rotational moment occur, for example, because the lubrication of the mandrel bar differs depending on its position, which causes a change in the coefficient of friction between the mandrel bar and the drilled blank pipe, but this can be compensated for by the method described above. be able to.

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

In FIG. 1, three rolls 1, 2 and 3 surrounding a mandrel bar 4 are shown in a partial and sectional view. Since the mandrel bar 4 is pushed into the hollow material to be rolled into a perforated blank pipe, the rolled material 5Fi exists between the mandrel bar 4 and the rolls 1 to 3. It can be clearly seen that the rolled material 5 is spaced apart from the surface of the mandrel bar 4 in the region of the roll nip indicated by reference numeral 6 and forms 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. According to the present invention, the formation of a bulge is almost completely eliminated, although it is suppressed to a low level.

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. The mandrel bar 4 and the shirt 4a connected to extend it are axially movable in the guide 11 by means of a motor 10.

Moreover, this movement is carried out together with the mandrel barbuncher 12, which incorporates a rotary movement mechanism for the sleeve (4a) and therefore also for the mandrel bar (4). FIG. 3 illustrates the rolling line according to FIG. 2,
In this figure, the mandrel bar 4 and the shirt 4a are shown in a state of being pushed forward. Since the hollow material 9 has already been sufficiently rolled, the perforated blank tube 3 protrudes from the roll stand on the exit side. mandrel bar
4 also has a roll stand protruding somewhat 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 pusher 12 is connected to the motor 10 (second
(FIGS. 3 and 3) is slidably driven in the axial direction via a lug 15 which is driven from K 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 pusher 12, but rotatably supported. Two motors 16, in particular hydraulically actuated, each drive two pinions 1 via one positively rotating latch 17.
8, these pinions together drive gear wheels 19, the rotary movement of which is transmitted directly to the mandrel bar 4 via the shaft 4a.

[Brief explanation of the drawing]

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. 123... e-roll 4... mandrel bar 5... rolled material 6... roll gap 7... bulging portion 8... lateral 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.