JPH0565243B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for perforating seamless pipes using inclined rolls using two inclined rolls.

[Conventional technology]

The Mannesmann type drilling machine, which is currently most widely used, has a pair of barrel-shaped rolls with the largest diameter part in the center, and this pair of rolls has a roll surface angle of 3 to 5 degrees. 5 mutually against the pass line
It is arranged at an inclination angle of ~13°. This angle of inclination is formed to feed the billet material, and is formed so that the two rolls are inclined in opposite directions. A plug for drilling is held by a mandrel at a predetermined position between both rolls, and guide shoes are provided between the rolls for holding down the hollow shell from both sides. In such a punching machine, the rolls that have an inclination angle to each other rotate in the same direction, so when the heated material enters from the roll inlet, it moves forward while being rotated by the rolls. This effect makes it easier to make a hole in the center of the material, and the tip of the plug makes the hole.

However, in such conventional perforation methods, a barrel-type roll is used in which the diameter of the body on the exit side is gradually smaller than the center of the roll, so the material is difficult to deform in the longitudinal direction on the exit side from the center of the roll. There is a major problem in that the shear deformation in the circumferential direction and the thickness direction becomes large, and as a result, flaws called lap flaws are likely to occur on the inner surface of the material.

In order to improve such problems, the special public
No. 23473 and Special Publication No. 60-59042 have been proposed.

FIG. 8 is an explanatory diagram showing a horizontal roll using these proposed techniques, a is a plan view thereof, and b is a side view thereof. As shown in the figure, this technology installs two rolls 1a and 1b on the horizontal plane of the pass line (if it is a rigid roll, it is installed on the vertical plane of the pass line), and the axes of the two rolls 1a and 1b are inclined so that they intersect on the roll entrance side, and the crossing angle γ is adjusted to an optimum value.

This moves the intersection point of rolls 1a and 1b forward,
That is, the holes are formed closer to the roll entry side. In this way, by using a so-called cone-shaped roll whose diameter expands toward the exit side and performing perforation with the roll arrangement such that the intersection point of rolls 1a and 1b protrudes forward, the body of the cone-shaped roll on the roll exit side can be formed. The diameter can be increased, and as a result, the material is easily rolled in the longitudinal direction, shear deformation in the circumferential direction and thickness direction is reduced, and the occurrence of inner surface defects is reduced. Figure 1 schematically shows the metal flow of the shell after perforation by the method using a barrel-shaped roll (Figure 1 A) and the method using a cone-shaped roll (Figure 2 B). In the method using this method, shear deformation (torsion) in the circumferential direction is significantly reduced as shown in the figure.

[Problems with conventional technology]

However, in the technology of Japanese Patent Publication No. 49-23473 and Japanese Patent Publication No. 60-59042, two rolls 1a,
1b is placed on the horizontal or vertical plane of the pass line, and its axes are tilted so that they intersect on the roll entry side, so the exit side parts of rolls 1a and 1b are As a result, it was difficult to make the equipment more compact, and there were cases where the existing equipment could not be used as is. Also, since the cross angle γ is given to the roll axis and its value is adjusted, it is necessary to adjust the cross angle γ in addition to the inclination angle for billet feeding (α in Figure 8). However, compared to the conventional Mannesmann method, there was a problem in that the settings were more complicated. In particular, when changing rolls, rolls 1a, 1
It was necessary to set the roll axes in the reference position once and then tilt the roll axes, which made the rearranging work extremely complicated. Another problem was that the mechanism, roll drive mechanism, and roll changing mechanism were complicated.

The present invention was made in view of such conventional problems, and it is possible to perform a perforation method using a cone-shaped roll without complicating the device configuration of the perforation machine.
Further, the purpose is to provide a perforation method that allows roll adjustment to be performed extremely easily.

[Means and Examples for Solving the Problem] In the conventional drilling method using cone-shaped rolls, not only the roll axis has an inclination angle for feeding the billet, but also the axis of the two rolls has an angle of inclination on the roll entry side. The above-mentioned problem occurred because the configuration was such that a crossing angle (γ in FIG. 8) was also provided so that the wheels crossed at the front. To solve this problem, if the pass line and the roll axis are arranged parallel to each other without giving the roll axis an intersecting angle, theoretically, the roll exit can be achieved while the roll exit side diameter remains large. This makes it possible to suppress the spread of the side rolls, and also makes it easy to adjust the roll arrangement.

However, in an actual line, if the rolls are simply arranged on the horizontal or vertical plane of the pass line without giving an intersecting angle to the axes of the cone rolls, the billet to be processed will be shaped as shown in Figure 9. Because of the need for extremely strong clamping, the diameter of the hollow shell on the exit side of the roll must be set extremely small, or the diameter of the billet to be processed on the input side must be set extremely large. It will be completely impossible to operate as a scheduler.

Therefore, based on the above points, the present inventors fundamentally reviewed and considered the conventional roll arrangement, and as a result, the roll axis was moved closer to the pass line center line, and the pass line was moved horizontally or It has been found that by displacing the rolls from the vertical direction around the pass line, the crossing point of the rolls can be formed forward, that is, closer to the roll entry side, simply by providing an inclination angle for billet feeding. here,
To move the roll axis around the pass line so that it approaches the pass line center line means, from another perspective, to move the contact point of the roll to the billet to be processed to the side with a smaller body diameter. That is, to explain using FIG. 10, rolls 1a, 1
b from the position where the large diameter part is in contact with the billet 4 to be processed and lined up in a straight line on the horizontal or vertical plane as shown in figure a, to the small body diameter part as shown in figure b. The purpose is to move it to a position where it comes into contact with the billet 4 to be processed. Roll 1a,
By displacing 1b in this way, the intersection point of axes 5a and 5b can be formed forward as shown in Fig. 9c, and of course the workpiece billet 4 can be strongly There will be no need to pinch it.

The present invention was devised based on such findings, and is based on a cone-shaped roll whose diameter is expanded toward the exit side of the pass line, and whose axis is aligned either horizontally or vertically with respect to the pass line. In a seamless pipe inclined roll perforation method using two inclined rolls arranged at an inclined angle, the axis of the cone-shaped roll is maintained parallel to the pass line direction without an inclined angle. As it is,
This is characterized in that the pass line is displaced from the horizontal or vertical direction around the pass line so as to approach the center line of the pass line.

The details of the present invention will be explained below.

The present invention uses a pair of so-called cone-shaped rolls whose diameter increases toward the exit side of the pass line, and an inclination angle to either the horizontal or vertical direction for billet feeding at the axis of the rolls. , and while keeping the axis parallel to the pass line direction with no inclination angle, move around the pass line from the pass line horizontal direction or vertical direction, approaching the pass line center line. As a result, as described above, the perforation is performed with the intersection point of the rolls being formed forward, that is, closer to the roll entry side. In the present invention, which uses a so-called cone-shaped roll whose diameter expands toward the exit side, the roll axis is
It is possible to perform perforation by arranging the rolls in such a way that the intersection point of the rolls protrudes forward in the same way as in those conventional technologies, without adding the crossing angle in the prior art. The diameter can be increased, and as a result, the material is easily rolled in the longitudinal direction, shear deformation in the circumferential direction and thickness direction is reduced, and the occurrence of inner surface defects is reduced. According to the method of the present invention, shear deformation (twisting) in the circumferential direction is caused by the first
As shown in Figure B, this will be significantly reduced.
Of course, since the roll axis is displaced from the pass line horizontal or vertical direction so as to approach the pass line center line, there is no need to pinch the workpiece billet extremely strongly as in the case of Fig. 9. It has become a thing.

FIGS. 2 to 4 show one embodiment of the present invention, and this embodiment can be called a rigid type.

In the figure, 1a and 1b are rolls (upper roll and lower roll because this embodiment is of a rigid type), 2 is a plug, 3 is a guide disk, 4 is a billet to be processed, and 4' is a hollow shell.

The upper and lower rolls 1a, 1b have trunks whose diameters increase toward the exit side of the pass line, and the axes 5a, 5b are given an inclination angle α only with respect to the horizontal direction, and the axes 5a, 5b are inclined at an angle α only with respect to the horizontal direction. 5b is set at a position displaced around the pass line so as to approach the pass line center line L from vertical positions a ₁ , a ₁ sandwiching the pass line center line L.

A billet 4 to be processed, which enters from the inlets of the rolls 1a and 1b, is rolled between the oblique lower part and the oblique upper part of the body of the rolls 1a and 1b, and is perforated by a plug 2 located between the rolls. In this type of rolling, the intersection point of the rolls is formed closer to the front, which allows rolling using cone-shaped rolls with a larger diameter on the exit side of the rolls. By rolling with such a cone-shaped inclined roll with a large body diameter on the roll exit side, the material to be rolled is easily rolled in the longitudinal direction, and this makes it easier to roll the material in the circumferential direction and thickness direction. Shear deformation is reduced.

In the present invention, the guide disk 3 is arranged at an angle due to the arrangement of the rolls 1a and 1b. In some cases, this guide disk may be modified as shown by the chain line 3' in FIG. 2.

FIGS. 5 and 6 show another embodiment of the present invention, which can be called a horizontal type, whereas the above embodiment is a rigid type.

That is, the rolls 1a and 1b have their axis 5.
An inclination angle α is attached to a and 5b only in the vertical direction, and furthermore, the axes 5a and 5b are moved from horizontal positions a ₂ and b ₂ sandwiching the pass line center line L to the pass line center line L. It is set at a position displaced around the pass line so as to approach it, and drilling is performed in the same manner as in the above embodiment.

As described above, in the method of the present invention, since the roll axis is only given an inclination angle in one direction,
different angles perpendicular and horizontal to the roll axis;
That is, compared to the conventional perforation method using cone-shaped rolls with intersecting angles, the roll drive mechanism and roll changing mechanism can be made compact and simple.

Figure 7 shows how seamless pipes of various sizes were manufactured using the method of the present invention using a model mill, and the incidence of internal laps (inner surface defects) was calculated using the method of the present invention using a model mill. The results of comparison with pipes are shown, and it can be seen that seamless pipes in which inner surface defects are appropriately suppressed can be efficiently manufactured by the method of the present invention.

〔Effect of the invention〕

According to the present invention described above, compared to the conventional perforation method using cone-shaped rolls, the roll arrangement can be adjusted extremely easily, and the roll drive mechanism and roll changing mechanism can be compact. have.

In addition, since the exit side of the rolls does not expand in any way, it is sufficient to use the same equipment as before, and it is easy to improve and use the existing equipment. . Of course, similar to the conventional cone-type roll perforation method, by reducing shear deformation in the circumferential direction and wall thickness direction during perforation, it is possible to appropriately suppress the occurrence of tube inner surface defects.
High quality seamless pipes can be manufactured efficiently.

[Brief explanation of the drawing]

FIGS. 1A and 1B schematically show the metal flow of the shell after perforation by the method using a barrel-type roll and the method using a cone-type roll, respectively. 2 to 4 show one implementation state of the present invention, with FIG. 2 being a front view, FIG. 3 being a side view, and FIG. 4 being a plan view. 5 and 6 show other implementation situations of the present invention, with FIG. 5 being a front view and FIG. 6 being a side view. FIG. 7 shows an example of the incidence of defects on the inner surface of seamless pipes obtained by the method of the present invention and the conventional method. FIG. 8 is an explanatory diagram of the system using a cone-type roll disclosed in Japanese Patent Publication No. 49-23473 and Japanese Patent Publication No. 60-59042, in which a is a plan view and b is a side view. Figure 9 shows the special public service issued in 1978.
FIG. 23473 and Japanese Patent Publication No. 60-59042 are explanatory diagrams showing the configuration of the cone-shaped rolls in which no intersecting angle is provided, in which a is a plan view and b is a side view. 10th
The figures are diagrams illustrating how to displace the roll of the present invention, in which a is a side view showing the roll position as a reference for starting displacement, b is a side view showing the roll position at which displacement is completed, and c is a side view of b. FIG. In the figure, 1a and 1b are rolls.

Claims (1)

[Claims] 1. A cone-shaped roll whose diameter expands toward the exit side of the pass line is arranged so that its axis has an inclination angle with respect to either the horizontal direction or the vertical direction of the pass line. In the inclined roll perforation method of a seamless pipe using a two-roll inclined roll, the axis of the cone-shaped roll is kept parallel to the pass line direction without an inclined angle, and the pass line center line is An inclined roll drilling method for seamless pipes, characterized in that the pass line is displaced from the horizontal or vertical direction around the pass line so as to approach the pass line.