JPH05177221A - Method for inclination-rolling tube - Google Patents

Abstract

PURPOSE:To prevent the peeling in the terminal part of a tube material from being generated when perforation rolling or drawing is carried out by an inclined rolling mill provided with a disk roll as a guide member. CONSTITUTION:The terminal of the tube material 4 fed along a pass line X-X, while suppressing expansion outward by disk rolls 2, 2 and rolled by inclined rolls 2, 2 is detected by a terminal detector 7 arranged in front of the inclined rolls 1, 1 and disk rolls 2, 2 and the result is given to a controller 9. The controller 9 issues an operation command to a roll opening adjuster 5 and a guide interval adjuster 6 after a terminal detection is performed and a set time set to a setter 11 elapses. The roll opening adjuster 5 and the guide interval adjuster 6 perform an operation for increasing the roll opening and the guide interval respectively by a specified amount. In a manner, rolling in a specified range from the terminal of the tube material 4 is carried out in the roll opening and guide interval larger than another part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention rolls a pipe material between a pair of inclined rolls and an inner surface restricting tool such as a piercing and rolling machine (piercer) and a drawing and rolling machine (elongator) used in the Mannesmann pipe manufacturing method. Regarding the method.

[0002]

2. Description of the Related Art The Mannesmann pipe making method, which is widely adopted as a method for producing a seamless pipe, uses a round bar-shaped steel piece (billet) heated to a predetermined temperature in a heating furnace as a raw material. This billet is fed to a piercing and rolling machine (piercer) to pierce and roll to obtain a hollow shell, and if necessary, this hollow shell is fed to a stretching and rolling machine (elongator) to expand the diameter and reduce the wall thickness. At least obtain a rolled tube, feed the rolled tube or the hollow shell to various subsequent rolling mills, after stretch rolling to have a desired diameter and wall thickness, a reeler, a polishing tube by a sizer, It is a method of obtaining a product tube through a refining process of performing shape correction and sizing.

A piercer and an elongator used for carrying out the Mannesmann pipe manufacturing method as described above are provided with a pair of inclined rolls and guide members, which are opposed to each other across a predetermined pass line, and are arranged on the pass line. It is an inclined rolling mill equipped with inner surface restraints such as plugs and mandrels, and rolling by these (inclined rolling) is performed on the pipe material (billet in the case of piercer, hollow in the case of elongator) fed on the pass line. It is performed by applying a predetermined reduction between the inclined roll and the inner surface restricting tool.

FIG. 4 is a cross-sectional view showing a proper rolling state of the piercer. In the figure, 1 and 1 are inclined rolls, and 2,
Reference numeral 2 is a disk roll which is a guide member, and 3 is a plug which is an inner surface restricting tool. As shown in the figure, the inclined rolls 1 and 1 are arranged on both the left and right sides of the plug 3 so as to face the outer periphery of the plug 3 with a predetermined gap therebetween.

The pipe material 4 to be rolled is restrained inside and outside by the inclined rolls 1 and 1 rollingly contacting the outer circumference of the pipe material 4 and the plug 3 which is also penetrated into the shaft center portion, and a predetermined rolling force is applied between them. Is added and piercing-rolled. The rotation of the inclined rolls 1 and 1 is designed to occur around each of the different rotation axes that are inclined in the opposite direction by substantially the same angle with respect to the pass line of the pipe material 4, and the pipe material 4 rotates in accordance with this rotation. It is rolled while being screwed in the long direction.

The disc rolls 2 and 2 are large-diameter disc-shaped rolls having a circular arc-shaped hole type having a curvature corresponding to the outer diameter of the pipe member 4 on the peripheral surface, as shown in FIG. The inclined rolls 1, 1 are provided between the upper and lower sides and the outer circumference of the plug 3.
Are opposed to each other with a space slightly larger than that. Further, these disc rolls 2 and 2 are arranged so that the rolls 1 and 2 do not hinder the rotation of the rolls 1 and 1.
The width is smaller than the separation distance (roll opening degree) in the No. 1 gorge portion and is arranged with a predetermined gap between the inclined rolls 1 and 1 on both sides in the width direction.

Disk rolls 2, 2 arranged in this way
As shown in the drawing, each of the hole types is rolled on the outside of the pipe material 4 between the rolling positions by the inclined rolls 1 and 1, and is rotated about each central axis orthogonal to the pass line of the pipe material 4. In addition, it has an action of suppressing outward bulging of the pipe member 4 caused by the reduction.

[0008]

In the piercing and rolling with the piercer as described above, the inclined roll 1 is used according to the selected piercing ratio (= the length of the material billet / the length of the hollow shell to be obtained). , 1 roll opening and disc roll 2,
The rolling conditions such as the separation distance (guide spacing) between the two are set respectively, but in recent years, a large perforation ratio tends to be selected in order to reduce the work amount in the subsequent rolling mill. ..

However, when piercing and rolling is carried out at a high piercing ratio, the influence of elongation due to this rolling is accumulated and there is a subsequent portion for restraining the deformation between the inclined rolls 1 and 1 due to the reduction. In the vicinity of the end of the pipe material 4,
A phenomenon in which the tubular material 4 spreads in a flare shape, so-called bottom flare, occurs, which is caused by the inclined rolls 1 and 1 and the disc rolls 2 and 2.
There is a problem in that the peripheral wall of the pipe material 4 is bitten into the gap between the pipe member 4 and the pipe member 4 as shown in FIG. 5, resulting in defective shape (peeling), and the product yield is reduced.

Such a difficulty is peculiar to the piercer provided with the disk rolls 2 and 2 as a guide member,
It is solved by adopting a piercer equipped with a fixed guide shoe instead of the disc rolls 2 and 2, but the guide by the guide shoe is performed along with the sliding contact with the outer periphery of the pipe material 4,
Since this sliding contact acts as a resistance that hinders the threaded movement of the pipe 4, the hollow shell obtained as a result of the piercing and rolling is likely to have an uneven thickness, and in order to move the tube 4 in the screwed manner. There was a problem that the power load on the inclined rolls 1 and 1 increased.

The above-mentioned disadvantages are not limited to the piercer,
The same occurs in the elongator, which is a factor that hinders the stretching and rolling at a large stretching ratio (= the length of the hollow shell as the raw material / the length of the rolled tube to be obtained).

The present invention has been made in view of such circumstances, and when peeling occurs at the end portion of the pipe material during rolling by an inclined rolling machine such as a piercer or an elongator equipped with a disc roll as a guide member. It is an object of the present invention to provide an inclined rolling method for a pipe, which can prevent the above and improve the product yield.

[0013]

A method of slant rolling a pipe according to the present invention is a method of forming a pipe material which is screw-moved on a pass line by rotation of a pair of slant rolls which are arranged to face each other across a pass line. A reduction is applied between the inner surface restricting member penetrating into the axial position and the inclined roll, and the bulging of the pipe material accompanied with this is suppressed by a pair of disc rolls facing each other between the inclined rolls. In the method of inclined rolling of a pipe to be piercing-rolled or stretch-rolled, in rolling a predetermined length range from the end of the pipe material, increasing one or both of the distance between the inclined rolls and the distance between the disc rolls by a predetermined amount. Is characterized by.

[0014]

In the present invention, the end of the tube being rolled is detected in front of the installation position of the inclined roll by using an appropriate detection means, and the roll opening of the inclined roll is based on the time when this detection is made as a reference. By increasing the disc roll guide spacing or both by a predetermined amount, rolling of a predetermined length range from the end of the pipe material is performed with a roll opening and / or a guide spacing larger than those of other parts. However, the occurrence of bottom flare is suppressed to prevent the occurrence of peeling.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a schematic diagram showing an embodiment of a piercer of a pipe tilt rolling method according to the present invention (hereinafter referred to as the present invention method), and FIG. 2 is a partially enlarged transverse sectional view taken along line II-II of FIG.

The illustrated piercer includes a pair of inclined rolls 1,
1, a pair of disc rolls 2, 2 as guide members,
And a plug 3 which is an inner surface restricting tool. XX in the figure
Is a pass line of the pipe material (billet) 4 to be rolled, and as shown in FIG. 2, the inclined rolls 1 and 1 are arranged opposite to each other on both sides of the pass line XX. As shown in FIG. 1, they are rotationally driven about respective different rotation axes having a predetermined inclination angle β in opposite directions with respect to the pass line XX. The illustrated inclined rolls 1 and 1 are provided with a gorge portion 1a having an intermediate diameter between the small-diameter inlet side end and the large-diameter outlet side end, and the gorge portion 1a and the inlet side end and the outlet side are provided. The side end is formed into a cone-shaped roll which is tapered and is connected by the entrance side surface 1b and the exit side surface 1c, respectively, but these may have other shapes such as a barrel shape. ..

The disk rolls 2, 2 have a large-diameter disk shape, and as shown in FIG. 2, arcuate hole molds 20, 20 each having a curvature corresponding to the outer diameter of the pipe material 4 on its peripheral surface. And is placed in a position substantially aligned with the gorge portions 1a, 1a of the inclined rolls 1, 1 in the longitudinal direction of the pass line XX, with the pass line XX being sandwiched and facing each other on the upper and lower sides. And is driven to rotate about respective different central axes orthogonal to the pass line X-X. Further, the plug 3 has a shell shape as shown in the figure, is fixed to the tip of the mandrel bar 30, and is positioned so as to be able to move back and forth on the pass line XX.

FIG. 3 is an explanatory view showing the state of progress of piercing and rolling by the piercer having the above construction. The pipe material 4 fed along the pass line XX is first of all inclined rolls 1 and 1.
These are bitten between the entrance side surfaces 1b and 1b of the plug 3 and are rotated by the rotations inclined with respect to the pass line XX to give a rotational force and a progressive force. Reach the tip (see FIG. 3 (a)).

At this time, the plug 3 located on the pass line XX is inserted so as to be screwed into the axial center portion of the pipe member 4 which reaches the tip of the plug line XX, and serves to pierce the pipe member 4. The pipe material 4 after the plug 3 has penetrated is subjected to a predetermined reduction between the outer peripheral surface of the plug 3 and the inclined rolls 1 and 1, and progresses while being formed into a tubular shape (see FIG. 3 (b)), The diameter is expanded along the inclination of the projecting side surfaces 1c, 1c following the gorge portion 1a, and is delivered as a hollow shell 4 '(see FIG. 3 (c)).

FIG. 2 is a transverse cross-sectional view of the gorge portions 1a, 1a at corresponding positions. During the piercing and rolling of the pipe material 4 performed as described above, the disc rolls 2, 2 are changed to the gorge portions of the inclined rolls 1, 1. 1a, 1a each hole type at a position almost orthogonal to the rolling contact position
The members 20 and 20 are brought into rolling contact with the outside of the pipe material 4 to suppress the outward bulging of the pipe material 4.

For the piercing and rolling of the pipe 4 as described above, the gap between the gorge portions 1a and 1a of the inclined rolls 1 and 1 (roll opening R _g ) and the bottom of the die 20 and 20 of the disc rolls 2 and 2 are determined. The respective intervals (guide intervals G _g ) are appropriately set in accordance with the preselected drilling ratio. As shown in FIG. 1, a roll opening adjuster 5 for moving the inclined rolls 1 and 1 in a direction to move them toward and away from each other, and a roll opening adjuster 5 to the disk rolls 2 and 2 to move to and away from each other. A guide interval adjuster 6 for controlling the roll opening R _g and the guide interval G is provided by these operations.
_It is designed so that _g can be set.

When piercing and rolling with the piercer as described above,
As shown in FIG. 1, the method of the present invention for preventing bottom flare near the end of the pipe 4 and peeling caused by the flare detects the passage of the end of the pipe 4 in front of the inclined rolls 1, 1. And a load detector 8 such as a load cell for detecting the rolling load applied to the pipe material 4 at one or both of the supporting positions of the inclined rolls 1 and 1, while arranging the end detector 7 for
And the roll opening adjuster 5 and the guide interval adjuster 6 are driven by the operation of the control unit 9 to which these detection results are given. In addition, as the end detector 7, for example, a light emitting device and a light receiving device for a laser beam sandwiching the tube material 4 are provided so as to detect passage of the end when light emitted from the light emitting device is captured by the light receiving device. Can be used.

The controller 9 sets the change amounts of the roll opening R _g and the guide gap G _g based on the rolling information such as the inclination angle β of the inclined rolls 1 and 1, the traveling speed of the pipe 4, the perforation ratio and the like. The change amount setting device 10 and the time setting from when the end of the pipe 4 is detected by the end detector 7 to when the control is started are based on the rolling information and the information such as the arrangement position of the end detector 7. The output of the timer setter 11 is also provided.

The control unit 9 recognizes the start and end of rolling from the output of the load detector 8, starts the operation at the start of rolling, and monitors the output of the end detector 7. When the output of the end detector 7 changes due to the passage of the end of the pipe material 4, the roll opening adjuster 5 and the guide interval adjuster 6 operate after waiting for the time set in the timer setter 11 from this point. Issue a command.

According to this operation command, the roll opening adjuster 5
2 is a change operation for increasing the roll opening R _g by a predetermined amount set in the change amount setting device 10 by moving the inclined rolls 1 and 1 in directions away from each other as indicated by an outline arrow in FIG. Make up. On the other hand, the guide distance adjuster 6 also moves the disc rolls 2 and 2 in directions away from each other, as indicated by a white arrow in FIG.
The changing operation is performed to increase the guide interval G _g by the predetermined amount set to.

After that, when the end of rolling is recognized from the output of the load detector 8, the control unit 9 issues a return command to the roll opening adjuster 5 and the guide interval adjuster 6, and both adjusters 5 and 6 are returned. By this operation, the roll opening R _g and the guide interval G _g are returned to the state before the change, the series of operations is finished, and the process waits until the next rolling start.

By the operation of the control unit 9 as described above, the pipe material 4
In the piercing and rolling of the rolls, the roll opening R _g and the guide interval G _g set in advance are set until the vicinity of the end thereof.
However, in a predetermined length range from the end of the pipe member 4, as shown by a broken line in FIG. 2, the roll opening R _g and the guide interval G _g are each a predetermined amount. It is performed under the roll opening R _g ′ and the guide interval G _g ′ that are changed to be large.

And after this change is made,
Since the amount of reduction of the pipe material 4 by the inclined rolls 1 and 1 decreases as the roll opening increases, and the degree of suppression of the bulging of the pipe material 4 by the disk rolls 2 and 2 decreases as the guide interval increases. It is possible to effectively suppress the bottom flare generated at the end of the pipe member 4 and the peeling caused by the bottom flare.

To change the roll opening R _g ′ and the guide interval G _g ′, the time set by the timer setter 11 has passed after the end of the pipe 4 has passed the position where the end detector 7 is arranged. Since this is done at the time point, the length of the pipe material 4 rolled after changing the opening depends on the set time. This set time refers to rolling conditions such as the outer diameter of the pipe 4 and the piercing ratio that are input from the outside in the timer setter 11, and the moving speed of the pipe 4
It is automatically determined for each rolling process by using data relating to the length of the pipe material 4 such as the arrangement position of the end detector 7 and the opening is always changed at an appropriate position. ..

Further, 'change of the roll angle to, and from G _g G _g' from R _g R _g amount of change in each of the time change of the guide spacing to is the change amount setting unit 10, likewise from outside It is adapted to be individually determined using the input rolling conditions.

The roll opening adjuster 5 for adjusting the roll opening may be any as long as it can move the inclined rolls 1 and 1 together with their respective bearings (not shown). For example, a mechanical type including a screw mechanism that is rotationally driven by a motor, a hydraulic type that utilizes the forward / backward movement of a hydraulic cylinder, or the like may be used. The same applies to the guide distance adjuster 6 for changing the guide distance.

Further, in the present embodiment, both the roll opening R _g and the guide interval G _g are increased when rolling within a predetermined length range from the end of the pipe material 4, but either one of them may be increased. You can

Finally, Table 1 shows the results of tests conducted to demonstrate the effect of the method of the present invention. This test result shows that a solid billet having an outer diameter of 70 mm is used as the pipe material 4 to be rolled, and piercing and rolling are performed by a piercer to obtain a hollow shell 4 ′ having an outer diameter of 90 mm and a wall thickness of 6 mm. As a conventional method, when the roll opening and the guide interval are not changed at the end of the pipe material 4 (No. 1), when only the guide interval is changed (No. 2) as the method of the present invention, only the roll opening is Whether or not peeling occurred for each of the 20 hollow shells 4'obtained in the case of changing No. 3 (No. 3) and in the case of changing both the guide interval and roll opening (No. 4). Is the one that was investigated.

According to the method of the present invention, when the end of the pipe material 4 reaches the position 70 mm from the gorge portions 1a, 1a of the inclined rolls 1, 1, the change of the guide interval and the roll opening is started,
The former was continuously increased at a speed of 0.5 mm / sec and the latter at a speed of 0.3 mm / sec.

[0035]

[Table 1]

As shown in Table 1, in the conventional method, peeling was confirmed in all 20 pieces obtained by piercing and rolling under the above-mentioned conditions, whereas in the case of changing only the guide interval. The number of occurrences of peeling was 5, and when only the roll opening was changed, it was 7, and when both the guide interval and the roll opening were changed, the 20 Peeling did not occur in the hollow shell 4 ′, and it can be seen from these that the occurrence of peeling can be effectively suppressed by carrying out the method of the present invention.

In the present embodiment, the case of piercing and rolling in the piercer was described, but the scope of application of the method of the present invention is not limited to this, and all kinds of inclinations such as elongator equipped with a disc roll as a guide member. Needless to say, it can be applied to rolling mills and similar effects can be obtained.

[0038]

As described above in detail, in the method of the present invention, the interval between the inclined rolls, the interval between the disk rolls, or both of them is increased by a predetermined amount when rolling the pipe material within a predetermined length range. As a result, the rolling within the predetermined length range is performed with a larger roll opening and //
Or because it is carried out under the guide interval, the occurrence of bottom flare is suppressed, the occurrence of peeling due to this can be prevented in advance, and the thin wall that was previously impossible by the inclined rolling machine equipped with a disc roll. The present invention has excellent effects such as the production of pipes possible without lowering the product yield.

[Brief description of drawings]

FIG. 1 is a schematic view showing an implementation state of a method of the present invention in a piercer.

FIG. 2 is a cross-sectional view taken along the line II-II in FIG.

FIG. 3 is an explanatory diagram of a progressing state of piercing and rolling in a piercer.

FIG. 4 is a cross-sectional view showing a normal rolling state in the piercer.

FIG. 5 is a cross-sectional view showing a state where peeling occurs in the piercer.

[Explanation of symbols]

 1 Inclined Roll 2 Disc Roll 3 Plug 4 Tubular Material 5 Roll Opening Adjuster 6 Guide Interval Adjuster 7 End Detector 8 Load Detector 9 Controller

Claims (1)

[Claims] 1. An inner surface restricting tool and an inclined roll which are inserted into an axial center position of a pipe material which is screw-moved on the pass line by rotation of a pair of inclined rolls which are opposed to each other across a pass line. In the inclined rolling method of a pipe, which is subjected to piercing rolling or stretch rolling while suppressing the bulging of the tubular material due to this by a pair of disc rolls facing each other between the inclined rolls. The method of inclined rolling of a pipe, wherein one or both of the intervals between the inclined rolls and the intervals between the disk rolls are increased by a predetermined amount when rolling within a predetermined length range from the end of.