JPH0787929B2 - Rolling method for pipes with inclined roll mill - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for rolling a pipe by an inclined roll mill.

[Prior Art] As a method for rolling a metal function such as a seamless steel pipe, there is a method using an inclined roll rolling machine such as a piercer, an elongator, or a reeler. The inclined roll rolling machine is shown in Fig. 9 or 10.
As shown in the figure, a pair of rolling rolls 1 are arranged at an inclined angle with a constant advance angle, and a plug 2 is arranged at substantially the center of the rolling region surrounded by the rolling rolls 1 on both sides of the rolling region. And a guide shoe (fixed shoe 3 in FIG. 9 and roller shoe 4 in FIG. 10). The plug 2 is supported by the tip of a plug bar (not shown). In FIG. 10, 5 is a guide plate.

In the inclined roll rolling machine, the plug 2 is inserted into the shaft center portion of the material 6 to be rolled which is rolled by the both rolling rolls 1,
The material to be rolled 6 is thin-walled and rolled by the both rolling rolls 1 and the plug 2. Further, the outer surface of the raw pipe 6 during rolling is restrained by a guide shoe (fixed shoe 3 or roller shoe 4) to promote the stretching of the raw pipe 6 in the longitudinal direction, and the raw pipe 6 can be fixed on the rolling pass line. I am trying.

Here, in the conventional method of rolling a pipe by an inclined roll rolling machine, the center points of both guide shoes (fixed shoe 3 or roller shoe 4) are arranged on the roll center line connecting both rolling rolls 1, and The peripheral speeds of both rolling rolls 1 are set to be equal.

[Problems to be Solved by the Invention] However, in the above-described conventional method for rolling a pipe by the inclined roll rolling machine, the raw pipe and the plug during rolling abnormally vibrate centering around the mandrel bar, which causes a problem of chilling. There are inconveniences such as external defects and damage to rolling equipment.

An object of the present invention is to prevent abnormal vibration during rolling in an inclined roll rolling mill.

[Means for Solving the Problems] According to the first aspect of the present invention, a pair of rolling rolls are arranged at an inclination with a constant advance angle, and a plug is arranged at a substantially central portion of a rolling region surrounded by the rolling rolls. Then, in a method of rolling a pipe by an inclined roll rolling machine in which guide shoes are symmetrically arranged on both sides of the rolling region, the center points of both guide shoes are set to one of the roll center lines connecting the axes of both rolling rolls. It is arranged to be shifted to the side.

According to a second aspect of the present invention, each of a pair of rolling rolls is inclinedly arranged at a constant advance angle, a plug is arranged at a substantially central portion of a rolling region surrounded by each rolling roll, and guides are provided on both sides of the rolling region. In a method of rolling a pipe by means of an inclined roll rolling machine in which shoes are arranged, a peripheral speed difference is given to both rolling rolls.

In a third aspect of the present invention, a pair of rolling rolls are inclinedly arranged at a constant advance angle, a plug is arranged at a substantially central portion of a rolling region surrounded by the rolling rolls, and guides are provided on both sides of the rolling region. In a method of rolling a pipe with an inclined roll rolling machine having shoes arranged, the center points of both guide shoes are arranged so as to be offset to one side with respect to the roll center line connecting the axes of both rolling rolls, and both rolling rolls are arranged. The peripheral speed difference is given to the.

[Operation] In the inclined roll rolling mill, the material to be rolled is rolled by the rolling roll rotating at a high speed and the unstable plug which is supported by the tip of the plug bar and is not fixed. This unstable rolling state is stabilized by the force Fs (see FIG. 3) exerted by the guide shoe on the plug and the shell. The force Fs acts as a force to set the centers of the plug and the element pipe to the roll center line that connects the axes of both rolling rolls. The potential energy Us (= -∫Fsdx) of the plug and the tube under the action of this force Fs is shown in Fig. 4, and the plug and the tube are set to the valley of the potential energy Us, that is, the roll center line. Stabilize.

On the other hand, the rolling roll exerts a force Fr that tends to displace the plug and the shell to one of the roll centerlines (see Fig. 3), and the potential energy Ur of the plug and the shell under the action of this force Fr becomes the first. This is as shown in FIG.

The force Ft actually acting on the plug and the tube is the sum of the above Fs and Fr (see FIG. 3), and the actual potential energy Ut of the plug and the tube is the above potential energy.
It is the sum of Us and Ur (see Figure 4). As shown in FIG. 4, the potential energy Ut has two valleys or stable points K on both sides of the roll center line and is in a gentle state. Therefore, when there is little instability due to rotation of the stock pipe during rolling, strong reduction, etc., the plug and the stock pipe have potential energy on both sides of the roll center line.
Although it is stable in one of the Ut valleys, if the unstable element becomes large, vibration will occur in a wide range.

However, when the center points of both guide shoes are shifted to one side of the roll center point by ΔH, the above-mentioned force Fs changes as shown in Fig. 5, and the force Ft also changes accordingly. 5
It changes as shown in the figure. The potential energy Us changes as shown in FIG. 6, and the potential energy Ut also changes as shown in FIG. In this case, the valley of the potential energy Ut, that is, the stable point K becomes one and becomes a deep valley, so that the plug and the element tube are stabilized from the stable point without vibrating greatly.

In the present invention of claim 1, both guide shoes may be arranged symmetrically, and the center points of both guide shoes may be shifted to either side of the roll center line. Therefore, the shift directions of the center points of both guide shoes can be switched alternately according to the operation progress of the rolling mill, and as a result, the wear of both guide shoes can be equalized with each other.

Further, when giving the peripheral speed difference ΔN to both rolling rolls,
The aforementioned force Fr changes as shown in FIG. 7, and the force Ft also changes as shown in FIG. 7 accordingly. Further, the above-mentioned potential energy Ur changes as shown in FIG. 8, and accordingly, the potential energy Ut also changes to the eighth value.
It changes as shown in the figure. In this case, there is one valley of this potential energy Ut, that is, one stable point K,
Moreover, since it becomes a deep valley, the plug and the element tube are stabilized without vibrating greatly from the above-mentioned stable point.

Further, in the present invention, the center points of both guide shoes may be arranged so as to be shifted to one side with respect to the roll center line, and the peripheral speed difference may be imparted to both rolling rolls. Since the valley of the potential energy Ut, that is, the stable point K is also one and is also a deep valley, the plug and the element tube are stabilized from the above stable point without vibrating greatly.

[Embodiment] FIG. 1 is a front view showing an inclined roll rolling mill according to a first embodiment of the present invention. In this inclined roll rolling mill 10, each of a pair of rolling rolls 11 has a constant lead angle. Plugs are placed in the center of the rolling area surrounded by each rolling area by sloping arrangement.
12 are arranged, and fixed shoes 13 are symmetrically arranged on both sides of the rolling region.

Then, in the inclined roll rolling machine 10, the center points 13C of the both fixed shoes 13 are arranged so as to be offset to one side with respect to the roll center line 11C connecting the axes of the two rolling rolls 11, and both rollings are performed. A peripheral speed difference ΔN is given to the roll 11.

Therefore, according to the inclined roll rolling machine 10, as described above, the valley of the potential energy Ut of the plug 12 and the shell 14 is one, that is, the stable point K, and the valley is deep. Is stable without vibrating greatly from the above stable point.

Further, according to this inclined roll rolling machine 10, both fixed shoes are
13 are arranged symmetrically and the center point 13 of both fixed shoes 13
C may be offset to either side of the roll center line 11C. Therefore, it is possible to alternately switch the shift directions of the center points 13C of the fixed shoes 13 in accordance with the operation progress of the rolling mill 10, and as a result, wear of the fixed shoes 13 can be equalized with each other. it can.

It should be noted that the inclined roll mill 10 may be one that implements either one of the above.

FIG. 2 is a front view showing an inclined roll rolling mill according to a second embodiment of the present invention. The difference between the inclined roll rolling mill 20 and the rolling mill 10 is that it is driven by force instead of the fixed shoe 13. I used the drive roller shoe 21. Even with this inclined roll rolling machine 20, both roller shoes 21
The center point 21C of the rolls is arranged on one side with respect to the roll center line 11C, and the peripheral speed difference ΔN is given to both rolling rolls 11.

Therefore, according to the inclined roll rolling machine 20, as described above, the potential energy of the plug 12 and the shell 14 is reduced.
Since the valley of Ut, that is, the stable point K becomes one and becomes a deep valley, the plug 12 and the shell 14 are stabilized from the stable point without vibrating greatly.

It should be noted that this inclined roll rolling machine 20 may be one that implements either one of the above.

According to the experimental results of the inventor, the center points of both guide shoes are shifted by about -20 to 20 mm with respect to the roll center line, and / or the peripheral speed difference between both rolling rolls is different in the range of -20 to 20%. It is recognized that, when rolled, abnormal vibration during rolling can be effectively prevented.

In an elongator using a drive roller shoe, when rolling a blank pipe with a diameter of 7.5 / 8 inch, 8.5 / 5 inch, and an outlet wall thickness of 15-25 mm, roll the center point of both roller shoes. By offsetting ΔH = 5mm from the center line and giving a peripheral speed difference ΔN = 7% to both rolling rolls, the abnormal vibration of 30G generated in conventional rolling can be suppressed to a stable rolling state of 2 to 3G. I was able to. Moreover, the surface defects of the blank pipe caused by abnormal vibration, which occurred at a rate of 7 to 8% in the conventional rolling, could be reduced to 0%.

[Effects of the Invention] As described above, according to the present invention, it is possible to prevent abnormal vibration during rolling in an inclined roll rolling mill.

[Brief description of drawings]

FIG. 1 is a front view showing a first embodiment of the present invention, FIG. 2 is a front view showing a second embodiment of the present invention, and FIG. 3 is a view when the center points of both guide shoes are on the roll center line. A diagram showing the force exerted by the guide shoe and the rolling roll on the plug and the tube, FIG. 4 is a diagram showing the potential energy corresponding to FIG. 3 of the plug and the tube, and FIG. 5 is the center point of both guide shoes. Is a diagram showing the force exerted by the guide shoe and the rolling roll on the plug and the tube when the sheet is displaced from the roll center line, and FIG. 6 is a diagram showing the potential energy corresponding to FIG. 5 of the plug and the tube. FIG. 7 is a diagram showing the force exerted by the guide shoe and the rolling roll on the plug and the blank pipe when a peripheral speed difference is applied to both rolling rolls.
Figure is a diagram showing potential energy corresponding to Fig. 7 of plugs and shells, Fig. 9 is a front view showing an inclined roll mill equipped with a conventional fixed shoe, and Fig. 10 is equipped with a conventional roller shoe. It is a front view which shows the inclined roll rolling machine. 10 …… Inclined roll rolling machine, 11 …… Rolling roll, 11C …… Roll center line, 12 …… Plug, 13 …… Fixing shoe, 13C …… Center point, 14 …… Under pipe, 20 …… Inclined roll rolling Machine, 21 …… Roller shoe, 21C …… Center point.

Claims (3)

[Claims] 1. A pair of rolling rolls are inclinedly arranged at a constant advance angle, a plug is arranged at a substantially central portion of a rolling region surrounded by the rolling rolls, and guide shoes are provided on both sides of the rolling region. In a method of rolling a pipe by means of a symmetrically arranged inclined roll rolling machine, the center point of both guide shoes is arranged so as to be displaced to one side with respect to the roll center line connecting the axes of both rolling rolls. Rolling method for pipes using a rolling mill. 2. A pair of rolling rolls are arranged so as to be inclined at a constant advance angle, a plug is arranged at a substantially central portion of a rolling region surrounded by the rolling rolls, and guide shoes are provided on both sides of the rolling region. A method for rolling a pipe by means of an inclined roll rolling machine, which is characterized in that a peripheral speed difference is given to both rolling rolls. 3. A pair of rolling rolls are inclinedly arranged at a constant advance angle, a plug is arranged at a substantially central portion of a rolling region surrounded by the rolling rolls, and guide shoes are provided on both sides of the rolling region. In the rolling method of the pipe by the arranged inclined roll rolling machine, the center points of both guide shoes are arranged so as to be displaced to one side with respect to the roll center line connecting the axes of both rolling rolls, and the circumferences of both rolling rolls are set. A method of rolling a pipe by an inclined roll rolling machine, which is characterized by imparting a speed difference.