JPS6384704A - Method and apparatus for cold pilger rolling - Google Patents

Abstract

PURPOSE:To prevent the exfoliation and crack of rolling roll surfaces and to improve productivity by exerting tensile force to a pipe material under rolling in the longitudinal direction thereof to decrease rolling down force. CONSTITUTION:An oil pressure is applied to a chuck 11 of a stock pipe holder 10 and a chuck 16 of a gripping mechanism 14, respectively, when a sequence controller 25 operates to supply a control signal to a hydraulic controller 20. The chuck 11 closes to grip the entire circumference of the stock pipe securely, thereby fixing and holding the same. The chuck 16 closes as well to grip the entire circumference of the product pipe 4 securely and to engage integrally with the product pipe 4. The hydraulic controller 20 supplies the pressure oil to a cylinder 15 to retract the cylinder by the prescribed tensile force, thereby exerting the tensile force in an arrow A direction to the gripping mechanism 14. On the other hand, rolling rolls 1, 1 rotate forward in an arrow C direction while moving in the arrow A direction by a prescribed distance to roll the stock pipe. Since the product pipe 4 is thereby kept pulled in the arrow A direction, the compressing force on the stock pipe by the rolling rolls 1, 1' is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cold pilger rolling method and apparatus for rolling a raw tube into a product tube by a cold pilger mill.

(Prior art) As shown in Fig. 3, the cold pilger rolling method uses a 1&l;
The seamless pipe material (hereinafter referred to as the raw pipe) 3 is sandwiched between the rolling rolls 1.1 of 1 on the mandrel 2, and the rolling rolls 1,1
This is a rolling method in which the raw pipe 3 is rolled by reciprocating along the longitudinal direction of the raw pipe 3 to form a seamless pipe (hereinafter referred to as a product pipe) 4 having a predetermined diameter and wall thickness. The raw pipe 3 to be rolled is a circular pipe, and the rolled product pipe 4 is also a circular pipe.

The mandrel 2 and the blank tube 3 are stationary, and when the housing (not shown) incorporating the rolling rolls 1.1 makes a reciprocating motion in the direction of arrow A or B, the set of rolling rolls moves in synchronization with the reciprocating motion. 1.1 is a mechanism in which the raw pipe 3 is repeatedly rolled on the mandrel 2 by rotating forward (in the direction of arrow C) or reversely (in the direction of the arrow), and the raw pipe 3 is rolled every time one round of rolling is completed. It is fed by a feed carriage chuck 5 to a predetermined length and at a predetermined angle, for example, 60''.
The cross-sectional shape is rolled into a perfect circle by rotating it one by one.

In such a cold pilger rolling apparatus, during rolling, the raw tube 3 is lightly fixed by an inlet chuck 6, and the product tube 4 is lightly fixed by an outlet chuck 7, and the tube material is elongated while sliding on the outlet chuck 7 as it is rolled. Note that one end of the mandrel 2 on the feed side of the raw tube 3 is gripped and fixed by a mandrel rod clamp chuck 8.

(Problems to be Solved by the Invention) However, in the cold pilger rolling described above, compressive force is always applied to the pipe material during the rolling process in order to prevent the rolled pipe material from popping out over the entire area during the rolling process. ing. For this reason, the efficiency of extruding the pipe material is poor,
The rolling blade of the roll roll rises, and the strength of the rolling equipment including the roll roll is insufficient, and the surface pressure of the roll roll becomes high (this makes it easy for the roll surface to peel or crack, which restricts the processing speed of the mother pipe. This is a major factor in preventing improvements in productivity.

The present invention was made in order to solve the above-mentioned problems, and is designed to lower the rolling edge of the roll during rolling, prevent peeling and cracking on the roll surface, and improve productivity. An object of the present invention is to provide a cold pilger rolling method and apparatus.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a cold pilger that rolls the raw pipe into a product pipe using rolling rolls that reciprocate along the longitudinal direction of the raw pipe. - A cold pilger rolling method in which a tensile force is applied in the longitudinal direction to the pipe material being rolled, and a cold pilger rolling device for carrying out the above rolling method, which is arranged on the side of the raw pipe and is used for rolling. a base pipe holding device that is activated during rolling to hold and fix the base pipe; a tensile force applying device that is disposed on the product pipe side and is activated during rolling to apply a tensile force to the product pipe; and the base pipe holding device and a hydraulic control device that controls the tensile force applying device; and a control device that drives the hydraulic control device at a predetermined timing during rolling to operate the blank pipe holding device and the tensile force applying device. A cold pilger rolling machine is provided.

(Function) By applying a tensile force in the direction in which the product tube is extruded during rolling, the maximum reduction edge of the rolling rolls during rolling can be reduced. This reduction in the reduction blade makes it possible to increase the processing speed during rolling. In addition, during rolling, the raw pipe is fixedly held by a raw pipe holding device, and the rolled product pipe is fixed to a tensile force applying device, and a hydraulic control device is driven at a predetermined timing by a control device, so that the raw pipe holding device and the tensile force applying device are operated to apply a tensile force to the tube material being rolled in the rolling direction. This reduces the maximum reduction edge of the roll during rolling.

(Example) An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Note that the same members as in FIG. 3 are given the same reference numerals.

In FIG. 1, the rolling rolls 1.1 with a diameter of 1 mm are formed with grooves that gradually reduce in diameter along the circumferential direction on the outer circumferential surface of the rolls 1.1, as described above, and these rolling rolls 1.1 are connected to arrows A or 1 of the housing (not shown). The mandrel 2 moves forward and backward in accordance with the reciprocating motion in direction B, and also rotates forward in the direction shown by arrow C or reversely in the direction shown by arrow in synchronization with the column or backward movement.
The raw tube 3 is repeatedly rolled on the holder to form a product tube 4 of a predetermined diameter.

The raw tube holding device 10 is arranged and fixed at a position near the feed carriage chuck 5, and the raw tube holding device 10 is attached to the raw tube 3.
A chuck 11 that is fitted onto the outside and is operated to open and close by hydraulic pressure, and a chuck 8
It is composed of a housing 12 that holds a boar chuck 11, and the chuck 11 opens when feeding the raw pipe 3 to enable feeding of the raw pipe 3, and closes during rolling to allow the raw pipe 3 to be fed.
Firmly grasp and fix. This raw pipe holding device 10 is
0.31 to the hydraulic control device 20.

Tension force applying device! f13 is disposed at a predetermined position on the exit side of the product tube 4, and the gripping mechanism 14, which is composed of a gripping mechanism 14 for gripping the product tube 4 and a tensile force applying mechanism 15, holds the product in the same way as the blank tube holding device 10. It is composed of a chuck 16 that fits onto the tube 4 and is opened and closed by hydraulic pressure, and a housing 17 that holds the chuck 16, and is capable of reciprocating a predetermined distance along the movement direction of the product tube 4. Chuck 1
6 opens when feeding the blank tube 3 to enable feeding of the blank tube 3 and the product tube 4 integrated with the blank tube 3, and allows the chuck 16 to return to its original position as described later, and closes during rolling. The product tube 4 can be firmly gripped and moved together with the product tube 4. Said chuck 16 is connected to a hydraulic control device 20 via oil lines 32,33.

The tensioning force applying mechanism 15 is constituted by, for example, a hydraulic cylinder, and the cylinder 15 is arranged on the outlet side of the gripping mechanism 14 and parallel to the moving direction of the product tube 4 . This cylinder 15 has one end of a rod 15a fixed to one end of the housing 17 of the gripping mechanism 14, and the rod 15a
The gripping mechanism 14 is movable by expanding and contracting.

That is, the cylinder 15 moves the gripping mechanism 14 in the direction of arrow A when the rod 15a is retracted, and moves the gripping mechanism 14 in the direction of arrow B when the rod 15a is extended. This cylinder 14 is connected to a hydraulic control device 20 via an oil line 34,35,
A predetermined tensile force, for example, 6 tons, is shortened to pull the gripping mechanism 14 in the direction of arrow A, thereby applying a tensile force to the product tube 4.

The hydraulic control device 20 is connected to a hydraulic pump 21 via an oil path 36, and is driven by a control device 25, which will be described later, to control each chuck 11.1 of the raw pipe holding device 10 and the gripping mechanism 14.
The cylinder 15 is controlled to open and close, and the cylinder 15 is expanded and contracted.

In the middle of the oil passage 36, there is an accumulator 22 for maintaining the hydraulic pressure of the hydraulic oil supplied to the hydraulic control device 20 at a predetermined pressure.
is connected.

The control device 25 is, for example, a sequence control device, and the sequence control device 25 is connected to the rotating shaft 1a of one of the rolling rolls 1.1 via a cam mechanism (not shown). It operates in synchronization with the rotation of the hydraulic control device 120, and sequentially outputs control signals at predetermined timings and supplies them to the hydraulic control device 2o, thereby operating the hydraulic control device 120.

The action will be explained below.

After the rolling roll 1.1 completes its return movement in the direction of arrow B,
The feed carriage chuck 5 grips the raw pipe 3 and feeds it a predetermined length in the direction of arrow A, and rotates the raw pipe 3 by the predetermined rotation angle of 60''.At this time, the chuck 11 of the raw pipe holding device 10 and the gripping mechanism 14 chucks 16
is open, and the base pipe 3 and product pipe 4 are movable in the direction of arrow A. Next, the sequence control device 2
5 operates to supply a control signal to the hydraulic control device 20.

Upon receiving the control signal, the hydraulic control device 20 supplies pressure and oil to the chuck 11 of the tube holding device 10 and the chuck 16 of the gripping mechanism 14, respectively, closes the chuck 11, and firmly grips the entire circumference of the tube 3. At the same time, the chuck 16 is closed to firmly grasp the entire circumference of the product tube 4 and engage it integrally with the product tube 4.

Next, the hydraulic control device 20 supplies pressure oil to the cylinder 15 to retract the cylinder 15 with the predetermined tensile force (6 tons), and applies a tensile force in the direction of arrow A to the gripping mechanism 14. On the other hand, the rolling rolls 1 and (2) rotate normally in the direction of arrow C while moving a predetermined distance in the direction of arrow A to roll the raw pipe 3. During this forward rolling, the product tube 4 is pulled by the gripping mechanism 14 in the direction of the arrow A with the aforementioned tensile force, so that the compressive force applied to the raw tube 3 by the rolling rolls 1.1 is significantly reduced. After the forward rolling of the rolls 1 and 1 is completed, these rolls 1.1 move backward in the direction of the arrow B and reverse in the direction of the arrow.

Even during this backward movement of the rolling rolls 1.1, the product pipe 4 is pulled by the tensioning force in the direction of the arrow A by the gripping mechanism 14, so that the compressive force on the raw pipe 3 by the rolling rolls 1.1 is reduced. be done.

When the rolling of the raw pipe 3 by the reciprocating motion of the rolling rolls 1.1 is completed and these rolling rolls 1 and 1 return to their original positions, the hydraulic side W device 20 opens the chuck 16 of the gripping mechanism 14 to release the product pipe. 4, the chuck 11 of the tube holding device 10 is opened to release the bond with the tube 3. Next, the loft 15a of the cylinder 15 is extended to move the gripping mechanism 14 in the direction of arrow B, thereby returning the gripping mechanism 14 to its original position. In this way, one round of rolling of the raw tube 3 by the rolling rolls 1.1 is completed.

After the rolling roll 1.1 finishes the one round of rolling, the feed carriage chuck 5 moves the raw tube 3 again as described above.
is gripped and fed in the direction of arrow A by a predetermined length, and the raw tube 3 is rotated by the predetermined rotation angle of 60'' to start the second rolling.Such rolling is repeated and the raw tube 3 A product tube 4 is formed from this.

As described above, by applying the tensile force to the product tube 4 during rolling, the compressive force applied to the tube material is reduced, and as a result, the maximum rolling edge applied to the rolling rolls 1, 1 can be reduced.

The graph shown in Figure 2 shows the maximum reduction blade when rolling a pure copper tube with an outer diameter of 80 m, a wall thickness of R¥, and a 10 fi finish into a finished pipe with an outer diameter of 45 mm and a wall thickness of 2.5 mm. Represents the relationship with the tensile force, and each curve ■~■ has a section of 0.9.0
．． 75. As is clear from the curves ■ and ■ in this graph, which show the maximum reduction blade at each cefsilane position of 0.2, the reduction blade decreases as the tensile force increases. Note that the dimensions of the outer diameter and wall thickness of the tube material being rolled differ depending on the position of cefsilane, so even if a tensile force is applied at the exit side, the tensile stress differs depending on the position of each section. For this reason, as shown by the curve {circle around (2)}, the lowering of the reduction blade increases as it approaches the outlet side of the product pipe. In addition, as shown by the curve ■, even at the 0 and 75 section positions where the rolling blade is at its maximum, the maximum rolling blade is approximately 10
It decreased by about %. This makes it possible to improve the durability of the mill roll, that is, extend the life of the mill roll. In addition, the life of the rolling roll is maintained as it is without lowering the maximum reduction blade applied to the rolling roll, and the outer diameter is 45 mm and the wall thickness is 2.
, When forming a 5-piece product pipe, change the raw pipe dimensions to an outer diameter of 8.
It becomes possible to increase the thickness to 3 cranes and the wall thickness to 110 mm, making it possible to improve productivity by about 13%.

(Effects of the Invention) As explained above, according to the present invention, in the cold pilger rolling method and apparatus for rolling the raw pipe into a product pipe using rolling rolls that reciprocate along the longitudinal direction of the raw pipe, Since a tensile force is applied to the tube material in the longitudinal direction during the rolling process, it is possible to reduce the maximum reduction edge of the rolls during the rolling process, and the surface pressure of the rolls is low ( 91 on the roll surface
18 and cracks are reduced, the durability of the rolling roll is improved, and the life of the rolling roll can be extended.

Furthermore, if the life of the roll is maintained as it is without lowering the maximum reduction blade of the roll, it becomes possible to increase the dimensions of the raw pipe, and as a result, productivity can be improved by more than 10%. It has excellent effects such as:

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of essential parts showing an embodiment of a cold pilger rolling device for carrying out the cold pilger rolling method according to the present invention, and Fig. 2 shows the maximum reduction blade applied to the rolling rolls and the tube material being rolled. A characteristic diagram showing the relationship with the applied tensile force, and FIG. 3 is a sectional view of the main part of a conventional cold bilger rolling mill. ■...Rolling roll, 2...Mandrel, 3...Made pipe, 4...Product pipe, 5...Feed carriage chuck, 10...Made pipe holding device, 11...Chuck,
13...Tensile force applying device, 15...Hydraulic cylinder,
16... Chuck, 20... Hydraulic control device, 21.
...Hydraulic pump, 22...Akinimulator, 25.
...Sequence control device, 30-35...Oil passage.

Claims (5)

[Claims] (1) In a cold pilger rolling method in which the raw pipe is rolled into a product pipe by rolling rolls that reciprocate along the longitudinal direction of the raw pipe, a tensile force is applied in the longitudinal direction to the pipe material being rolled. A cold pilger rolling method characterized by: (2) The cold pilger rolling method according to claim 1, wherein the tensile force is applied in a direction in which the product tube is extruded. (3) In a cold pilger rolling machine that rolls the raw pipe into a product pipe using rolling rolls that reciprocate along the longitudinal direction of the raw pipe, the machine is installed on the raw pipe side and is activated during rolling. a base pipe holding device that holds and fixes the base pipe;
a tensile force applying device disposed on the product pipe side and activated during rolling to apply a tensile force to the product pipe; a hydraulic control device controlling the raw pipe holding device and the tensile force applying device;
A cold pilger rolling device comprising: a control device that drives the hydraulic control device at a predetermined timing during rolling to operate the blank pipe holding device and the tensile force applying device. (4) The cold pilger rolling apparatus according to claim 3, wherein the raw pipe holding device is constituted by a hydraulic chuck that grips and fixes the outer peripheral surface of the raw pipe during rolling. . (5) The tensile force applying device includes a hydraulic chuck that grips and fixes the outer peripheral surface of the product tube during rolling, and is connected to the chuck and applies a predetermined tensile force to the chuck in the direction in which the product tube is pushed out during rolling. 4. The cold pilger rolling apparatus according to claim 3, further comprising a hydraulic cylinder for imparting.