JPS5856650B2 - How to roll hollow pieces - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an efficient rolling method for hollow pieces.

There are various methods for manufacturing seamless steel pipes using rolling means, but generally seamless steel pipes are manufactured by sequentially passing heated material through a piercing mill, an elongation mill, and a reduction mill. .

In the rolling of seamless steel pipes, first, the heated billet is perforated in the rolling direction by a perforation mill.

This drilling method includes the press roll drilling method and the press drilling method, but the pipe material drilled by these methods does not have a hollow hole of the same diameter completely penetrated, and it is necessary to use a drilling equipment such as a drilling plug or a pusher head. In order to prevent damage to the material, an unperforated portion is generally left at the rear end of the material and is formed into a so-called hollow piece with a bottom, or the diameter of the perforation at the rear end of the material is made small.

In this description, the so-called hollow pieces with a bottom, in which the rear end of the material is unperforated and the rear end is perforated with a small diameter, will be collectively defined as a hollow piece.

When rolling such a hollow piece into a long tube as a starting material, unless the Bush Bench method is used, it must be subjected to an intermediate treatment step to obtain a perforated tube with holes completely and uniformly perforated at both ends. .

In order to roll hollow tubes with such uniform through holes (hereinafter referred to as steady perforation holes), an inclined roll mill is used, and a set of two or three inclined rolls is used. A bullet-shaped plug supported by a mandrel is placed in the space to be formed, and this plug and the inclined rolls are used to roll the regular perforation and to roll the unperforated portion or the small diameter perforation at the rear end.

In such known inclined roll rolling, the entire length of the tube is rolled with only a short bullet-shaped plug, so that the plug is red-hot.

For this reason, it is necessary to replace the plug or cool the plug every time one tube is rolled.

Cooling or replacing such plugs takes time and inevitably reduces productivity.

In addition, in elongation rolling of a constantly perforated material using a mandrel rolling machine, a long mandrel is inserted into the perforated hole of the pipe material, and the mandrel is passed through a row of rolling mills consisting of grooved rolls arranged in series to roll the pipe to a predetermined thickness. For example, it is possible to
This was announced in Publication No. 987, etc.

However, in the above-mentioned known mandrel rolling, the material to be rolled has regular perforations at both ends, and a preliminary treatment step is required to provide regular perforations over the entire length of the material to be rolled. I need.

The present invention has been made for the purpose of providing a tube rolling method with an extremely simple process that does not have the above-mentioned drawbacks in rolling hollow pieces using an inclined roll rolling mill, and in which a plug and a mandrel are integrally formed with the same diameter. This mandrel (hereinafter simply referred to as the mandrel) is fully inserted into the hollow part of the hollow piece, and the constant perforation part is rolled while the pipe mandrel is integrally transferred, and the rear end perforation part or small diameter perforation part is rolled at the tip of the mandrel. It is characterized in that drilling and rolling are performed at the tapered part provided in the.

The details of the present invention will be further described below with reference to the drawings.

The figure shows the rolling method of the present invention broken down into several steps, and the apparatus for carrying out the method of the present invention will be described.

In the figure, 3-1 and 3-2 are inclined rolls disposed opposite to each other in a rolling mill (not shown), which are not particularly limited in the present invention and are generally used in pipe rolling. The inclined roll rolling mill used can be arbitrarily selected without departing from the object of the present invention.

Reference numeral 2 denotes a pusher for pushing the material to be rolled, that is, the hollow piece 1, which is provided on the rear surface facing the insertion side into the rolling machine, in the direction of the inclined rolls 3-L and 3-2.

Reference numeral 4 denotes a mandrel having a tapered portion 4 integrally formed at its tip, and is provided to have a length equal to or longer than the length of the hollow piece 1.

Further, the mandrel 4 is provided to coincide with the rolling axis IK of the hollow piece 1.

5-L 5-2.5-3.5-4 face each other across the rolled material transition line on the rear surface of the inclined rolling roll 3-L 3-2, and have an advancing/retreating device (not shown) in the direction of the rolled material transition line. 1) For example, a feed roll connected to a cylinder device or a link device.

This feed roll 5-i is further selectively connected to a suitable drive source.

Reference numeral 6 denotes a stopper for the mandrel 4, which crosses the transition line of the mandrel 4 so that the tapered part 4 at the tip of the mandrel 4 is located between the inclined rolls 3-1 and 3-2, corresponding to the length of the mandrel 4. It is installed so that it can move forward and backward.

The stopper 6 may be moved forward and backward toward the mandrel transition line by a rotating opening/closing mechanism in which one end is rotatably supported as shown in the illustrated example, or by a sling-opening mechanism without departing from the object of the present invention.
It may be a forward/retreat mechanism using a device (it can be selected and installed as desired).

Reference numeral 7 denotes a latch for the stopper 6, which supports the stopper 6 in closing.

The method of the present invention is carried out as follows using the apparatus arrangement as described above.

As shown in Figure 1, a billet with a square or round cross section that has been appropriately refined to be rolled into a pipe is left unperforated at the rear end using an appropriate punching machine, or a small diameter hole is punched. The hollow piece in which the part has been formed is brought to the artificial side of the inclined roll rolling mill and positioned with the perforation opening side facing the mandrel tapered part 4.

Then, the pusher 2 pushes the rear surface of the hollow piece 1 to move it to the rolling mill roll section.

Also, on the losing side of hollow piece 1, feed roll 5
- The mandrel 4 is clamped by i and the feedrow/l-5-i is fully operated to transfer the mandrel 4 to the hollow piece 1 and insert it into the perforation cavity 8 thereof.

The mandrel 4 may be fully inserted into the perforation cavity 8 of the hollow piece 1 before rolling, or may be continued during rolling.

However, the unperforated part 1 of the hollow piece 1 is the inclined roll 3-L.
The tapered part 4 of the mandrel 4 must fully reach the tip 1 of the perforation cavity 8 before reaching the rolling part 3-2.

FIG. 2 shows the state in which the pipe wall of the perforation part of the hollow piece 1 is rolled by the mandrel 4 and the diagonal rolls 3-1 and 3-2, but in this illustrated example, the tip of the mandrel 4 is still in the perforation cavity. Although the insertion is not completed at the tip 1 of the tube 8, the mandrel 4 and the hollow piece 1 move together in the rolling direction, and the tube wall is rolled to a predetermined thickness.

At this time, the feed roll 5-i has already been retracted.

As the rolling progresses, the mandrel 4 is stopped from moving by a stopper 6.

This situation is shown in FIG. Even after the mandrel 4 is stopped from moving by the stopper 6, the hollow piece moves forward, and the unpierced starting end of the hollow piece 1 is moved by the inclined roll 3-
The rolling process that reaches between L3-2 and presses the button is the same as perforation rolling with an inclined roll perforator, and the unperforated part 1 is formed between the inclined roll 3-L3-2 and the tapered part of the mandrel. 4 and the mandrel body adjacent thereto are punch-rolled to the same dimensions as the curved section.

As described above, in the present invention, a mandrel having a tapered part at the tip is inserted into the perforated part of the hollow piece 1 in advance, and the wall of the perforated part is rolled while the mandrel and the hollow piece are moved together. The transfer is stopped and that part is rolled using the tapered part and the inclined roll in the same manner as the perforated part.

After rolling the hollow piece 1, the stopper 6 and latch 7 are opened as shown in FIG. 4, and the feed roll 5-i
is activated to send the rolled tube to the next process, and at the same time, the mandrel 4 is moved in the opposite direction, that is, in the direction of the hollow piece 9 waiting for the next rolling, using feed rolls, and the same process as shown in FIG. 1 is carried out. Rolling is performed repeatedly.

Further, according to the present invention, rolling can be performed while forcing the mandrel 4 to rotate around its central axis.

Since the rolling method of the present invention is as described above, the mandrel is used over its entirety, and the actual load application time to each part is extremely short, and there is no localized wear and tear on the mandrel, and it can be used repeatedly for a long time. It can be performed.

Conventionally, after removing the plug after rolling, the mandrel and tube are advanced simultaneously in the rolling direction, the tube is placed against a stripper block, the mandrel is pulled out, the tube is removed, the mandrel is advanced again, and the plug is attached after the mandrel is fixed in position. However, in the present invention, the mandrel only needs to be sent back through the rolling line while the rolled pipe is being delivered to the next process, and there is no time loss at all.

Furthermore, in the method of the present invention, it is possible to reduce the occurrence of poor biting of the material to be rolled by the inclined rolls, and at the same time, the feed roll 5 can be
- By pulling the mandrel in the rolling direction by i, biting can be facilitated and the biting speed can be increased.

This foreign car invention can improve the rolling speed and enable long length rolling.

[Brief explanation of the drawing]

Figures 1 to 4 show the rolling method of the present invention divided into processes. Figure 1 is before rolling, Figure 2 is mandrel rolling of the perforated area, and Figure 3 is the rolling state of the unperforated area. Figure 4 shows the movement of the mandrel after rolling.

Claims (1)

[Claims] 1. When a hollow piece is rolled into a pipe using an inclined roll rolling mill, a mandress with a tapered tip is inserted into the perforation of the hollow piece, the hollow piece is integrally moved between the mandrel and the rolling roll, and the hollow piece is rolled. The perforated part of the hollow piece is rolled by a mandrel and a rolling roll, the transition of only the mandrel is stopped by a stopper, and the perforated part at the rear end of the hollow piece is rolled by the tapered head of the mandrel and an inclined rolling roll. rolling method. 2. When a hollow piece is rolled into a pipe with an inclined roll rolling mill, a mandrel with a tapered tip is inserted into the perforated part of the hollow piece, the hollow piece is integrally moved between the mandrel and the rolling roll, and the perforated part of the hollow piece is connected to the mandrel. Rolling is performed using a rolling roll, and then only the mandrel is stopped from moving with a stopper, and the rear end perforated portion of the hollow piece is rolled by the tapered head of the mandrel and an inclined rolling roll, and then the kneading mandrel is pulled out in the opposite direction to the rolling pipe and transferred. A method for rolling a hollow piece, characterized by: