JP7654602B2 - Rolling equipment for electric resistance welded steel pipe manufacturing - Google Patents

Description

The present invention relates to a rolling machine for manufacturing electric-resistance welded steel pipes, which manufactures electric-resistance welded steel pipes by butting together and welding both edges of a blank pipe made of a plate material formed into a tubular shape. In particular, the present invention relates to a rolling machine for manufacturing electric-resistance welded steel pipes, which is capable of easily adjusting the position of the grooved rolls provided in the rolling machine for manufacturing electric-resistance welded steel pipes and capable of manufacturing high-quality electric-resistance welded steel pipes.

As is well known, electric resistance welded steel pipes (also called electric resistance welded steel pipes, ERW steel pipes) are manufactured in a pipe manufacturing line by forming a sheet material (steel plate) unwound from a coil into a tube shape with a roll, and then butting and welding (electric resistance welding) both edges (both edges perpendicular to the longitudinal direction of the sheet material formed into a tube, i.e., both edges in the circumferential direction of the blank pipe) of the tubular plate material (in this specification, the tubular plate material is called the "bare pipe") together. This electric resistance welding is a method in which an induction coil to which high-frequency power is applied is used to generate eddy currents in both edges of the blank pipe, and both edges of the blank pipe heated by the eddy currents (induction heating) are pressed together with a grooved roll (also called a squeeze roll). The grooved roll is a roll with an arc-shaped groove (groove) with a curvature corresponding to the outer diameter of the blank pipe formed on its outer surface, and the both edges of the blank pipe are pressed together by contacting the outer surface of the blank pipe with the groove of the grooved roll.

The weld quality of electric resistance welded steel pipes depends greatly on the cross-sectional shape of the mother pipe at the time of welding and the V angle of the mother pipe at the time of welding (the angle formed by both edges of the mother pipe when viewed in a plan view immediately adjacent to the grooved rolls, also called the "weld convergence angle").
If the cross-sectional shape of the blank pipe during welding fluctuates, the balance of eddy currents on the inner and outer surfaces of the blank pipe is lost, and the discharge of molten metal becomes unstable (inducing cracks caused by inclusions due to oxide entrapment), deteriorating the weld quality. Furthermore, if welding is not performed with an appropriate V-angle, cold welding (a condition in which the weld is prone to peeling) and oxide entrapment occur, deteriorating the weld quality. Specifically, if the V-angle is too small, the range in which heat input can be controlled without causing both cold welding due to low heat input and oxide entrapment due to high heat input becomes narrow. In this specification, cold welding, oxide entrapment, and the like caused by poor welding conditions or fluctuations in welding conditions are collectively referred to as "welding defects."

As conventional rolling devices for manufacturing electric resistance welded steel pipes, devices disclosed in Patent Documents 1 and 2 have been proposed, for example.
The apparatus described in Patent Document 1 is configured to include a pair of grooved rolls (squeeze rolls 11, 12) disposed on one side and the other side of the mother tube in a horizontal direction perpendicular to the longitudinal direction of the mother tube (on the left and right sides of the mother tube) so as to surround the outer periphery of the mother tube. In this specification, an apparatus equipped with two grooved rolls, such as the apparatus described in Patent Document 1, will be referred to as a "two-roll apparatus" as appropriate.
The apparatus described in Patent Document 2 is configured to include a pair of upper and lower grooved rolls (side rolls 2, 3 and a pair of top rolls 4) arranged on one side and the other side of the mother tube in a horizontal direction perpendicular to the longitudinal direction of the mother tube (on the left and right sides of the mother tube). In this specification, an apparatus equipped with four grooved rolls, such as the apparatus described in Patent Document 2, is appropriately referred to as a "four-way roll apparatus."

In a two-roll device as described in Patent Document 1, one grooved roll holds about half of the outer periphery of the mother pipe (an outer periphery portion with a central angle of about 180°), so that the positions of both edges of the mother pipe are restrained by the grooved roll at an early stage before the mother pipe reaches the grooved roll, which tends to make the V angle small and tends to cause welding defects.
In contrast, in a four-roll apparatus as described in Patent Document 2, the positions of both edges of the blank pipe are hardly restricted by the grooved rolls until the outer surface of the blank pipe comes into contact with the upper grooved rolls (the pair of top rolls 4 in Patent Document 2). Therefore, compared to a two-roll apparatus, this has the advantage that the V-angle can be made larger, and the welding quality resulting from the V-angle can be easily and favorably stabilized.

Here, the grooved roll has an arc-shaped groove on its outer surface with a curvature according to the outer diameter of the blank tube, so the outer diameter of the grooved roll varies depending on the position in the direction of the center of rotation of the grooved roll. As a result, the peripheral speed (outer circumferential speed) of the grooved roll varies depending on the position in the direction of the center of rotation of the grooved roll. Therefore, the peripheral speed of the grooved roll varies depending on the position of the contact point between the blank tube and the grooved roll (the circumferential position of the blank tube), and there is a risk of defects (roll defects) occurring on the outer surface of the blank tube at the contact point where the difference between the longitudinal transport speed of the blank tube and the peripheral speed of the grooved roll becomes large.

In a two-roll device, as described above, it is necessary to hold about half of the outer periphery of the mother tube with one grooved roll (an outer periphery portion with a central angle of about 180°), so that the difference in the peripheral speed of the grooved roll becomes large depending on the position of the contact point between the mother tube and the grooved roll, and the risk of roll marks occurring becomes high. In particular, the larger the outer diameter of the mother tube, the larger the difference in the peripheral speed of the grooved roll depending on the position of the contact point between the mother tube and the grooved roll, and the more significant the risk of roll marks occurring.
In contrast, in a four-roll apparatus, the central angle of the outer peripheral portion of the mother tube held by one grooved roll is smaller than in a two-roll apparatus, so the difference in the peripheral speed of the grooved roll depending on the position of the contact point between the mother tube and the grooved roll is smaller, and the risk of roll marks occurring is reduced compared to a two-roll apparatus.

Furthermore, in a two-roll device, the positions of the two grooved rolls can be easily adjusted, and by adjusting the positions of the two grooved rolls to appropriate positions according to the desired cross-sectional shape of the mother pipe, the cross-sectional shape of the mother pipe during welding can be stabilized, and ultimately, the welding quality resulting from the cross-sectional shape of the mother pipe can be easily stabilized.
In contrast, in a four-roll machine, the positions of the four grooved rolls are generally adjustable individually, so it is more difficult to adjust the positions of the four grooved rolls to appropriate positions according to the desired cross-sectional shape of the mother pipe than in a two-roll machine. As a result, the cross-sectional shape of the mother pipe at the time of welding may differ from the desired cross-sectional shape, and the welding quality due to the cross-sectional shape of the mother pipe may be unstable. In addition, a step (height difference) called a lap may occur on the surface (welding surface) where both edges of the mother pipe are butted together.

As described above, the two-roll device has the advantage that the position of the grooved roll can be easily adjusted, but has the disadvantage that the V-angle is easily made small, making welding defects more likely to occur, and the difference in the peripheral speed of the grooved roll becomes large depending on the position of the contact point between the mother tube and the grooved roll, increasing the risk of roll marks occurring.
On the other hand, a four-roll device has the advantages of making it easier to stabilize the welding quality resulting from the V-angle and reducing the risk of roll marks occurring, but it has the disadvantages that it is difficult to adjust the positions of the four grooved rolls to appropriate positions according to the desired cross-sectional shape of the mother pipe, which can lead to unstable welding quality due to the cross-sectional shape of the mother pipe, and laps are likely to occur on the welded surface.

Japanese Patent Application Publication No. 5-69037 Patent No. 5965096

The present invention has been made to solve the problems of the conventional technology as described above, and aims to provide a roll device for manufacturing electric-resistance welded steel pipes that is easy to adjust the position of the grooved rolls provided in the roll device for manufacturing electric-resistance welded steel pipes and can manufacture high-quality electric-resistance welded steel pipes.

In order to solve the above problems, the inventors conducted intensive research and discovered that by improving a conventional four-roll device, it is possible to both facilitate the position adjustment of the grooved rolls and produce a high-quality electric resistance welded steel pipe, thereby completing the present invention.
That is, in order to solve the above-mentioned problems, the present invention provides a rolling machine for manufacturing electric-resistance welded steel pipes, which manufactures electric-resistance welded steel pipes by butting together and pressing and welding both heated edges of a mother pipe made of a plate material formed into a tubular shape, characterized in that the rolling machine only comprises a first pair of grooved rolls arranged on one side of the mother pipe in a horizontal direction perpendicular to the longitudinal direction of the mother pipe so as to surround the outer periphery of the mother pipe, the first pair of grooved rolls being composed of a pair of upper and lower grooved rolls connected to each other, and a second pair of grooved rolls arranged on the other side of the horizontal direction perpendicular to the longitudinal direction of the mother pipe so as to surround the outer periphery of the mother pipe , the second pair of grooved rolls being composed of a pair of upper and lower grooved rolls connected to each other, and further comprises an expanding/contracting means capable of adjusting the horizontal separation distance between the first pair of grooved rolls and the second pair of grooved rolls, and a lifting/lowering means capable of adjusting the vertical separation distance between the first pair of grooved rolls and the second pair of grooved rolls.

According to the present invention, the first grooved roll pair arranged on one side in the horizontal direction with respect to the blank tube is composed of a pair of upper and lower grooved rolls connected to each other, and the second grooved roll pair arranged on the other side in the horizontal direction with respect to the blank tube is composed of a pair of upper and lower grooved rolls connected to each other. The horizontal separation distance between the first grooved roll pair and the second grooved roll pair can be adjusted by the expansion and contraction means. In other words, the pair of upper and lower grooved rolls connected to each other that constitute the first grooved roll pair are integrated, and the pair of upper and lower grooved rolls connected to each other that constitute the second grooved roll pair are integrated, and the horizontal separation distance between them can be adjusted by the expansion and contraction means. The vertical separation distance between the first grooved roll pair and the second grooved roll pair can be adjusted by the lifting means. In other words, the pair of upper and lower grooved rolls connected to each other that constitute the first grooved roll pair are integrated, and the pair of upper and lower grooved rolls connected to each other that constitute the second grooved roll pair are integrated, and the vertical separation distance between them can be adjusted by the lifting means.
Therefore, if the upper and lower pairs of grooved rolls constituting the first and second grooved roll pairs are connected in advance at appropriate positions according to the desired cross-sectional shape of the mother pipe, the positions of the four grooved rolls can be easily adjusted to appropriate positions according to the desired cross-sectional shape of the mother pipe by simply adjusting the horizontal separation distance between the first and second grooved roll pairs by the expansion and contraction means and adjusting the vertical separation distance between the first and second grooved roll pairs by the lifting and lowering means. Since the positions of the four grooved rolls can be adjusted to appropriate positions, the welding quality due to the cross-sectional shape of the mother pipe is easily stabilized and laps are less likely to occur on the welded surface compared to conventional four-roll devices. Furthermore, since the present invention is a type of four-roll device, the welding quality due to the V-angle is easily stabilized and the risk of roll marks occurring is reduced.
That is, according to the present invention, it is possible to easily adjust the position of the grooved rolls while simultaneously producing a high-quality electric resistance welded steel pipe.

Preferably, each of the grooved rolls constituting the first grooved roll pair and the second grooved roll pair has a center of rotation that is approximately perpendicular to a perpendicular line of the grooved profile that passes through the midpoint of the arc-shaped grooved profile.

In the above preferred configuration, the "cavity profile" refers to the outer edge shape of the cross section of the groove (the groove formed on the outer surface of the groove roll) obtained by cutting the groove roll along a plane passing through the center of rotation of the groove roll.
In addition, "approximately perpendicular to the perpendicular line of the groove profile" means that the angle between the perpendicular line of the groove profile and the center of rotation is 90° or close to that angle (within the range of 90°±10°).
According to the above-mentioned preferred configuration, the difference in the peripheral speed of the grooved roll depending on the position of the contact point between the mother tube and the grooved roll (the contact point between the outer surface of the mother tube and the groove of the grooved roll) is further reduced, thereby further reducing the risk of roll marks occurring.

Preferably, the upper grooved rolls constituting the first grooved roll pair and the second grooved roll pair each have a central angle of an arc-shaped groove profile of 40° or more and 50° or less.

According to the findings of the inventors, when the central angle of the groove profile of the upper grooved roll is less than 40°, the length of the groove profile is short (in other words, the length of the outer peripheral portion of the blank tube that contacts the groove of the upper grooved roll is short), so that the pressure force per unit circumference applied from the grooved roll to the blank tube becomes large, and there is a risk of roll marks occurring.
On the other hand, when the central angle of the groove profile of the upper groove roll exceeds 50°, the edge of the groove profile of the upper groove roll that is close to the groove profile of the lower groove roll is likely to be the first to come into point contact with the outer surface of the mother pipe before welding. When the edge of the groove profile of the upper groove roll comes into point contact with the outer surface of the mother pipe, the pressure applied from the groove roll to the part of the mother pipe that comes into point contact becomes large, and roll marks may occur. In addition, when there is point contact, there is also the problem that it is difficult to control the lap.
According to the above-mentioned preferred configuration, since the central angle of the groove profile of the upper groove roll is 40° or more and 50° or less, the above-mentioned problems are less likely to occur, and it is possible to produce electric-welded steel pipes of even higher quality.

Preferably, the upper grooved rolls constituting the first and second grooved roll pairs are attached to an upper housing, the lower grooved rolls constituting the first and second grooved roll pairs are attached to a lower housing, and the upper and lower housings are connected to connect the upper and lower grooved rolls constituting the first and second grooved roll pairs, respectively, and the upper grooved rolls are attached to the upper housing via a first spacer and a second spacer detachably attached to the upper housing, the first spacer is attached to the upper housing so that the position of the upper grooved roll along a direction perpendicular to the center of rotation of the upper grooved roll is adjusted according to its thickness, and the second spacer is attached to the upper housing so that the position of the upper grooved roll along the direction of the center of rotation of the upper grooved roll is adjusted according to its thickness.

When the groove of a grooved roll is worn out by use, it is common to re-use the grooved roll by modifying the groove in order to reduce costs. That is, it is common to remove the worn grooved roll from the housing, modify the groove, and then attach the modified grooved roll to the housing.
According to the above-mentioned preferred configuration, when the groove of the upper grooved roll removed from the upper housing is modified, it is possible to replace it with a first spacer having a larger thickness (by the amount of modification) than the thickness of the first spacer attached before modification, and to attach the modified upper grooved roll to the upper housing through this replaced first spacer. As a result, the vertical position of the upper grooved roll (more precisely, the position along the direction perpendicular to the rotation center of the upper grooved roll) approaches the center of the blank tube, and the groove of the upper grooved roll and the groove of the lower grooved roll are easily positioned on the same circumference, thereby reducing the effect of modification of the upper grooved roll.
In addition, according to the above-mentioned preferred configuration, when the groove of the lower grooved roll removed from the lower housing is modified, it is possible to replace it with a second spacer having a smaller thickness (smaller by the thickness according to the amount of modification) than the thickness of the second spacer attached before modification, and to attach the upper grooved roll to the upper housing through this replaced second spacer. This adjusts the horizontal (horizontal direction perpendicular to the longitudinal direction of the blank tube) position of the upper grooved roll (more precisely, the position along the direction of the rotation center of the upper grooved roll), and the groove of the upper grooved roll and the groove of the lower grooved roll are easily positioned on the same circumference, thereby reducing the effect of modification of the lower grooved roll. After that, if necessary, the horizontal separation distance between the first grooved roll pair and the second grooved roll pair can be reduced (the first grooved roll pair and the second grooved roll pair can be brought closer to each other) by the expansion/contraction means so that the diameters of the grooves of the first grooved roll pair and the second grooved roll pair match the outer diameter of the blank tube.

According to the present invention, it is easy to adjust the position of the grooved rolls, and it is possible to manufacture high-quality electric resistance welded steel pipes.

1 is a front view, partially in cross section, showing a schematic configuration of a rolling device for manufacturing an electric-resistance welded steel pipe according to an embodiment of the present invention. FIG. 2 is a front view showing a schematic example of a state in which the horizontal (Y direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2 is increased by the expansion/contraction means 3 shown in FIG. 1 . FIG. 2 is a front view showing a schematic example of a state in which the vertical (Z-direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2 is increased by the lifting means 4 shown in FIG. 1 . FIG. 2 is an enlarged schematic front view of a first grooved roll pair 1 shown in FIG. 1 .

Below, we will explain a roll device for manufacturing electric resistance welded steel pipes according to one embodiment of the present invention, with appropriate reference to the attached drawings.

Fig. 1 is a front view (viewed from the longitudinal direction of a mother pipe) showing a schematic configuration of a roll device for manufacturing an electric resistance welded steel pipe according to one embodiment of the present invention, partially in cross section. The X direction shown in Fig. 1 is the longitudinal direction of the mother pipe, the Y direction is the horizontal direction perpendicular to the longitudinal direction of the mother pipe, and the Z direction is the up-down direction. The same applies to the other figures. Note that the dimensions, scale, and shapes of the components shown in Fig. 1 may differ from the actual ones. The same applies to the other figures.
The rolling device 100 for manufacturing electric-resistance welded steel pipes according to this embodiment is a device for manufacturing electric-resistance welded steel pipes P by butting together and welding both edges of a blank pipe P' made of a plate material formed into a tubular shape. Specifically, the rolling device 100 for manufacturing electric-resistance welded steel pipes is installed downstream (downstream in the conveying direction of the blank pipe P') of an induction coil (not shown) for induction heating both edges of the blank pipe P' conveyed in the longitudinal direction (X direction), and is a device for manufacturing electric-resistance welded steel pipes P by butting together and pressing both edges of the heated blank pipe P'. The welded portion PW of the electric-resistance welded steel pipe P shown in FIG. 1 is a portion generated by butting together and welding both edges of the blank pipe P', and is located at the upper center of the electric-resistance welded steel pipe P.
As shown in Fig. 1, the rolling device 100 for producing electric-resistance welded steel pipes comprises a first pair of grooved rolls 1, a second pair of grooved rolls 2, an expansion/contraction means 3, and an elevation means 4. The rolling device 100 for producing electric-resistance welded steel pipes according to this embodiment also comprises housings 5 and 6. Each of these components provided in the rolling device 100 for producing electric-resistance welded steel pipes will be described below.

<First grooved roll pair 1>
The first grooved roll pair 1 is arranged on one side (the left side in the example shown in Figure 1 ) of the raw pipe P' in a horizontal direction (Y direction) perpendicular to the longitudinal direction (X direction) of the raw pipe P' so as to surround the outer periphery of the raw pipe P' (which becomes the electric welded steel pipe P after the weld PW is generated), and is composed of a pair of upper and lower grooved rolls 11, 12 connected to each other.
The first grooved roll pair 1 of this embodiment is attached to a housing 5 arranged on one side (left side in the example shown in FIG. 1) in the horizontal direction (Y direction) with respect to the blank pipe P'. The housing 5 includes an upper housing 51 and a lower housing 52, and the upper housing 51 and the lower housing 52 are connected and integrated by fastening means 53 such as bolts. The upper grooved roll 11 constituting the first grooved roll pair 1 is attached to the upper housing 51, and the lower grooved roll 12 constituting the first grooved roll pair 1 is attached to the lower housing 52. As described above, the upper housing 51 to which the upper grooved roll 11 is attached and the lower housing 52 to which the lower grooved roll 12 is attached are connected and integrated, so that the upper grooved roll 11 and the lower grooved roll 12 are also connected and integrated.

Specifically, the upper grooved roll 11 constituting the first grooved roll pair 1 is rotatably attached to a support shaft 111 via a bearing 112. The support shaft 111 is detachably attached to a holder 7a. The holder 7a is detachably attached to the upper housing 51 via a first spacer 8a and a second spacer 9a which are detachably attached to the upper housing 51. For example, the holder 7a is attached to the upper housing 51 by fastening means (not shown) such as bolts with the first spacer 8a and the second spacer 9a sandwiched therebetween.
On the other hand, the lower grooved roll 12 constituting the first grooved roll pair 1 is rotatably attached to a support shaft 121 via a bearing 122. The support shaft 121 is detachably attached to the lower housing 52.

<Second grooved roll pair 2>
The second caliber roll pair 2 is arranged on one side (on the right side in the example shown in FIG. 1 ) of the blank pipe P' in the horizontal direction (Y direction) perpendicular to the longitudinal direction (X direction) of the blank pipe P' so as to surround the outer periphery of the blank pipe P' (which becomes the electric resistance welded steel pipe P after the welded portion PW is generated), and is composed of a pair of upper and lower caliber rolls 21, 22 connected to each other. In the state shown in FIG. 1 , the second caliber roll pair 2 is arranged symmetrically with the first caliber roll pair 1 with respect to a reference line L, which is a virtual line that passes through the center PO of the assumed blank pipe P' and extends in the vertical direction (Z direction).
The second grooved roll pair 2 of this embodiment is attached to a housing 6 arranged on the other side (right side in the example shown in FIG. 1) of the horizontal direction (Y direction) with respect to the blank pipe P'. The housing 6 includes an upper housing 61 and a lower housing 62, and the upper housing 61 and the lower housing 62 are connected and integrated by fastening means 63 such as bolts. The upper grooved roll 21 constituting the second grooved roll pair 2 is attached to the upper housing 61, and the lower grooved roll 22 constituting the second grooved roll pair 2 is attached to the lower housing 62. As described above, the upper housing 61 to which the upper grooved roll 21 is attached and the lower housing 62 to which the lower grooved roll 22 is attached are connected and integrated, so that the upper grooved roll 21 and the lower grooved roll 22 are also connected and integrated.

Specifically, the upper grooved roll 21 constituting the second grooved roll pair 2 is rotatably attached to a support shaft 211 via a bearing 212. The support shaft 211 is detachably attached to a holder 7b. The holder 7b is detachably attached to the upper housing 61 via a first spacer 8b and a second spacer 9b which are detachably attached to the upper housing 61. For example, the holder 7b is attached to the upper housing 61 by fastening means (not shown) such as bolts with the first spacer 8b and the second spacer 9b sandwiched between them.
On the other hand, the lower grooved roll 22 constituting the second grooved roll pair 2 is rotatably attached to a support shaft 221 via a bearing 222. The support shaft 221 is detachably attached to the lower housing 62.

<Enlarging/reducing means 3>
The expansion/contraction means 3 is a means capable of adjusting the horizontal (Y direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2 .
The expansion/contraction means 3 of the present embodiment includes a rotating shaft 31, gears 32 to 35, screw shafts 36 and 37, and a base 38. The base 38 supports the housing 5 (specifically, the lower housing 52) and the lifting means 4 (specifically, the base 41 described below).
The rotating shaft 31 is attached to the base 38 by a predetermined attachment member (not shown) so as to be rotatable around the horizontal direction (Y direction). The rotating shaft 31 can rotate in either forward or reverse direction.
The gear 32 has teeth formed on its outer surface, and is fixed to an end portion on one side in the horizontal direction (Y direction) of the rotating shaft 31 (the left side in the example shown in FIG. 1 ). The gear 33 has teeth formed on its outer surface, and is fixed to an end portion on the other side in the horizontal direction (Y direction) of the rotating shaft 31 (the right side in the example shown in FIG. 1 ). When the rotating shaft 31 rotates in the horizontal direction (Y direction), the gears 32 and 33 also rotate in the same direction as the rotating shaft 31 in the horizontal direction (Y direction).

The gears 34, 35 are each attached to a base 38 by a predetermined attachment member (not shown) so as to be rotatable around the horizontal direction (Y direction). The gears 34, 35 have teeth formed on their outer surfaces and female threads formed on their inner surfaces.
The outer surface of the gear 34 meshes with the outer surface of the gear 32, and as the gear 32 rotates in the horizontal direction (Y direction), the gear 34 rotates in the horizontal direction (Y direction) in the opposite direction to the gear 32. For example, when viewed from any direction in the horizontal direction (Y direction), if the gear 32 rotates clockwise, the gear 34 rotates counterclockwise, and if the gear 32 rotates counterclockwise, the gear 34 rotates clockwise.
Similarly, the outer surface of the gear 35 meshes with the outer surface of the gear 33, and as the gear 33 rotates in the horizontal direction (Y direction), the gear 35 rotates in the horizontal direction (Y direction) in the opposite direction to the gear 33. For example, when viewed from any direction in the horizontal direction (Y direction), if the gear 33 rotates clockwise, the gear 35 rotates counterclockwise, and if the gear 33 rotates counterclockwise, the gear 35 rotates clockwise.

The screw shaft 36 has an external thread formed on its outer surface, and one end of the screw shaft 36 is fixed non-rotatably to the housing 5 (the lower housing 52). The outer surface of the screw shaft 36 meshes with the inner surface of the gear 34.
The screw shaft 37 has a male thread formed on its outer surface, and one end of the screw shaft 37 is non-rotatably fixed to the lifting means 4 (specifically, a base 41 described later) connected to the housing 6. The outer surface of the screw shaft 37 meshes with the inner surface of the gear 35.
The male thread formed on the screw shaft 36 and the male thread formed on the screw shaft 37 have a reverse thread relationship formed in opposite directions. Therefore, the female thread formed on the inner surface of the gear 34 that meshes with the screw shaft 36 and the female thread formed on the inner surface of the gear 35 that meshes with the screw shaft 37 also have a reverse thread relationship formed in opposite directions.

In order to adjust the horizontal (Y direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2 by the expansion/contraction means 3 having the configuration described above, the rotation shaft 31 is rotated about the horizontal (Y direction) direction. The rotation of the rotation shaft 31 may be performed manually, for example, by attaching a handle (not shown) to one end of the rotation shaft 31, or may be performed automatically by attaching a motor capable of rotating forward and backward to one end of the rotation shaft 31.
As the rotating shaft 31 rotates, the gear 32 also rotates, and the gear 34 meshing with the gear 32 also rotates. Similarly, as the rotating shaft 31 rotates, the gear 33 also rotates, and the gear 35 meshing with the gear 33 also rotates. The rotation direction of the gear 34 and the rotation direction of the gear 35 are the same.
As described above, the male thread formed on the screw shaft 36 and the male thread formed on the screw shaft 37 have a reverse thread relationship formed in opposite directions. One end of the screw shaft 36 and one end of the screw shaft 37 are fixed so as not to rotate. Therefore, as the gears 34 and 35 rotate in the same direction, the screw shafts 36 and 37 move in opposite directions to each other in the horizontal direction (Y direction).
For example, when viewed from any direction in the horizontal direction (Y direction), consider a case where, as the rotation shaft 31 rotates clockwise, the gears 34 and 35 rotate counterclockwise, so that the screw shaft 36 and the screw shaft 37 move away from each other, with the screw shaft 36 moving to the left relative to the gear 34 and the screw shaft 37 moving to the right relative to the gear 35. In this case, as the rotation shaft 31 rotates counterclockwise, the gears 34 and 35 rotate clockwise, so that the screw shaft 36 and the screw shaft 37 move closer to each other, with the screw shaft 36 moving to the right relative to the gear 34 and the screw shaft 37 moving to the left relative to the gear 35.

Fig. 2 is a front view showing a schematic example of a state in which the horizontal (Y direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2 is expanded by the expansion/contraction means 3 (the first grooved roll pair 1 and the second grooved roll pair 2 are moved away from each other from the state shown in Fig. 1). In Fig. 2, the illustration of the blank pipe P' (electric resistance welded steel pipe P) is omitted. The same applies to Figs. 3 and 4 described below.
As can be seen by comparing Fig. 2 with Fig. 1, the screw shaft 36 shown in Fig. 2 moves leftward relative to the gear 34 from the state shown in Fig. 1, and the screw shaft 37 shown in Fig. 2 moves rightward relative to the gear 35 from the state shown in Fig. 1. As the screw shaft 36 moves leftward, the housing 5 to which one end of the screw shaft 36 is fixed also moves leftward on the base 38, and the first grooved roll pair 1 attached to the housing 5 also moves leftward. As the screw shaft 37 moves rightward, the lifting means 4 to which one end of the screw shaft 37 is fixed also moves rightward on the base 38, and the housing 6 connected to the lifting means 4 also moves rightward. As a result, the second grooved roll pair 2 attached to the housing 6 also moves rightward.

The operation of the expansion/contraction means 3 described above expands the horizontal (Y direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2. When reducing the horizontal (Y direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2, the direction of rotation of the rotating shaft 31 may be reversed from that when expanding the separation distance.
In this embodiment, the pitch of the teeth formed on the outer surfaces of the gears 32 and 33 is the same. The pitch of the teeth formed on the outer surfaces of the gears 34 and 35 is the same. Furthermore, the pitch of the female threads formed on the inner surfaces of the gears 34 and 35 (the pitch of the male threads formed on the outer surfaces of the screw shafts 36 and 37) is the same. Therefore, the movement amount of the screw shafts 36 and 37, and therefore the movement amount of the first grooved roll pair 1 and the movement amount of the second grooved roll pair 2 are the same. Therefore, as shown in FIG. 1, before adjusting the horizontal (Y direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2, if the first grooved roll pair 1 and the second grooved roll pair 2 are arranged line-symmetrically with respect to the reference line L as shown in FIG. 1, the line-symmetric relationship will be maintained even after the horizontal (Y direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2 is adjusted by the expansion/contraction means 3.

<Lifting Means 4>
The lifting means 4 is a means capable of adjusting the vertical (Z direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2. Specifically, the lifting means 4 in this embodiment is a means capable of adjusting the vertical (Z direction) position of the second grooved roll pair 2.
The lifting means 4 of the present embodiment includes a base 41 , a bolt portion 42 , and a nut portion 43 .
The bolt portion 42 has a male thread formed on its outer surface, and is attached to the base 41 so as to be rotatable in the vertical direction (Z direction). The bolt portion 42 can rotate in either forward or reverse direction. The male thread of the bolt portion 42 is inserted into a cavity 411 formed inside the base 41.
The nut portion 43 has an internal thread formed on its inner surface, and is fixed to the housing 6 (specifically, the lower housing 62) so as not to rotate. The nut portion 43 is disposed in the cavity 411 of the base 41, and the inner surface of the nut portion 43 meshes with the outer surface of the bolt portion 42.

In order to adjust the vertical (Z-direction) separation distance between the first pair of perforated rolls 1 and the second pair of perforated rolls 2 by the lifting means 4 having the above-described configuration, the bolt portion 42 is rotated around the vertical (Z-direction) direction. The bolt portion 42 may be rotated manually, for example, by attaching a handle (not shown) to the upper end of the bolt portion 42, or automatically, by attaching a motor capable of rotating forward and backward to the upper end of the bolt portion 42.
As described above, the outer surface of the bolt portion 42 and the inner surface of the nut portion 43 mesh with each other, and the nut portion 43 is fixed to the housing 6 so as not to rotate, and therefore, as the bolt portion 42 rotates, the nut portion 43 moves in the vertical direction (Z direction) relative to the bolt portion 42 within the cavity 411 of the base 41. For example, when viewed from either the vertical direction (Z direction), if the bolt portion 42 rotates clockwise to cause the nut portion 43 to rise, then the bolt portion 42 rotates counterclockwise to cause the nut portion 43 to fall.

FIG. 3 is a front view showing a schematic example of a state in which the lifting means 4 has increased the separation distance between the first grooved roll pair 1 and the second grooved roll pair 2 in the vertical direction (Z direction) (the first grooved roll pair 1 and the second grooved roll pair 2 are moved away from each other from the state shown in FIG. 1 ).
As can be seen by comparing Fig. 3 with Fig. 1, the nut portion 43 shown in Fig. 3 has moved upward with respect to the bolt portion 42 from the state shown in Fig. 1. When the nut portion 43 moves upward, the housing 6 to which the nut portion 43 is fixed also moves upward, and the second grooved roll pair 2 attached to the housing 6 also moves upward.
The above-described operation of the lifting means 4 increases the vertical (Z-direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2. To reduce the vertical (Z-direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2, the rotation direction of the bolt portion 42 may be reversed from that in the case of increasing the separation distance.

As described above, according to the roll device 100 for manufacturing electric resistance welded steel pipes according to this embodiment, if the upper and lower pairs of grooved rolls 11 to 22 constituting the first grooved roll pair 1 and the second grooved roll pair 2 are connected in advance at appropriate positions according to the desired cross-sectional shape of the mother pipe P', the positions of the four grooved rolls 11 to 22 can be easily adjusted to appropriate positions according to the desired cross-sectional shape of the mother pipe P' simply by adjusting the horizontal (Y direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2 by the expansion/contraction means 3 and adjusting the vertical (Z direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 1 by the lifting/lowering means 4. Since the positions of the four grooved rolls 11 to 22 can be adjusted to appropriate positions, it is easier to stabilize the welding quality due to the cross-sectional shape of the mother pipe P' and less likely to cause laps on the welded surface compared to the conventional four-way roll device. In addition, since the rolling machine 100 for manufacturing electric-resistance welded steel pipes is a type of four-way roll machine, it is easy to stabilize the welding quality caused by the V-angle, and the risk of roll marks occurring is reduced.
In other words, according to the roll device 100 for manufacturing electric-resistance welded steel pipes according to this embodiment, it is possible to both easily adjust the position of the grooved rolls 11 to 22 and manufacture high-quality electric-resistance welded steel pipes P.

FIG. 4 is an enlarged schematic front view of the first grooved roll pair 1. As shown in FIG.
As shown in Figure 4, the upper grooved roll 11 that constitutes the first grooved roll pair 1 is positioned so that its rotation center C1 (which corresponds to the center line of the support shaft 111 in this embodiment) and the perpendicular line N1 of the arc-shaped grooved profile P1 passing through the midpoint M1 of the grooved profile P1 (a point located midway between both edges E1a, E1b of the grooved profile P1) form an angle θ1 when viewed from the longitudinal direction (X direction) of the blank tube P'.
In addition, the lower grooved roll 12 that constitutes the first grooved roll pair 1 is positioned so that its rotation center C2 (which corresponds to the center line of the support shaft 121 in this embodiment) and the perpendicular line N2 of the arc-shaped grooved profile P2, which passes through the midpoint M2 of the grooved profile P2 (a point located midway between both edges E2a, E2b of the grooved profile P2), form an angle θ2 when viewed from the longitudinal direction (X direction) of the blank tube P'.

In this embodiment, the angles θ1 and θ2 are both set to 90° or close to it (within the range of 90°±10°). In other words, each of the grooved rolls 11 and 12 constituting the first grooved roll pair 1 has a rotation center that is approximately perpendicular to the perpendicular line of the grooved profile passing through the midpoint of the grooved profile.
Although not shown in Figure 4, the second grooved roll pair 2 is similarly configured, with each of the grooved rolls 21 and 22 constituting the second grooved roll pair 2 having a rotation center that is approximately perpendicular to the perpendicular line of the grooved profile passing through the midpoint of the grooved profile.
Since the first grooved roll pair 1 and the second grooved roll pair 2 in this embodiment have the above-mentioned preferred configuration, the difference in the peripheral speed of the grooved rolls 11-22 depending on the position of the contact point between the base tube P' and the grooved rolls 11-22 (the contact point between the outer surface of the base tube P' and the grooves of the grooved rolls 11-22) is further reduced, and the risk of roll marks occurring is further reduced.

As shown in FIG. 4, the upper grooved roll 11 constituting the first grooved roll pair 1 has an arc-shaped groove profile P1 centered on point C and having a central angle α.
In this embodiment, the central angle α is set to be equal to or greater than 40° and equal to or less than 50°.
Although not shown in FIG. 4, the central angle of the groove profile of the upper grooved roll 21 constituting the second grooved roll pair 2 is similarly set to be 40° or more and 50° or less.
Since the first grooved roll pair 1 and the second grooved roll pair 2 of this embodiment have the above-mentioned preferred configuration, problems such as the occurrence of roll marks and difficulty in controlling the lap are less likely to occur, making it possible to produce an electric welded steel pipe P of even higher quality.

Furthermore, as shown in FIG. 4, the first spacer 8a is attached to the upper housing 51 so that the position of the upper grooved roll 11 along the direction perpendicular to the rotation center C1 of the upper grooved roll 11 constituting the first grooved roll pair 1 (the D1 direction shown in FIG. 4) is adjusted according to its thickness. Specifically, when the thickness (dimension in the D1 direction) of the first spacer 8a increases, the position of the holder 7a approaches the center of the blank tube P' along the D1 direction. As a result, the position of the upper grooved roll 11 also approaches the center of the blank tube P' along the D1 direction. Conversely, when the thickness of the first spacer 8a decreases, the position of the holder 7a moves away from the center of the blank tube P' along the D1 direction. As a result, the position of the upper grooved roll 11 also moves away from the center of the blank tube P' along the D1 direction.

Also, as shown in FIG. 4, the second spacer 9a is attached to the upper housing 51 so that the position of the upper grooved roll 11 along the direction of the center of rotation C1 of the upper grooved roll 11 constituting the first grooved roll pair 1 (the D2 direction shown in FIG. 4) is adjusted according to its thickness. Specifically, when the thickness (dimension in the D2 direction) of the second spacer 9a increases, the position of the holder 7a moves to the right along the D2 direction. As a result, the position of the upper grooved roll 11 also moves to the right along the D2 direction. Conversely, when the thickness of the second spacer 9a decreases, the position of the holder 7a moves to the left along the D2 direction. As a result, the position of the upper grooved roll 11 also moves to the left along the D2 direction.

Although not shown in FIG. 4, the first spacer 8b attached to the upper grooved roll 21 constituting the second grooved roll pair 2 is also attached to the upper housing 61 so that the position of the upper grooved roll 21 along the direction perpendicular to the center of rotation of the upper grooved roll 21 is adjusted according to its thickness. The second spacer 9b is also attached to the upper housing 61 so that the position of the upper grooved roll 21 along the direction of the center of rotation of the upper grooved roll 21 is adjusted according to its thickness.

The first spacers 8a, 8b and the second spacers 9a, 9b can be, for example, a stack of shim plates of a predetermined thickness, although this is not limited thereto. If the first spacers 8a, 8b and the second spacers 9a, 9b are configured with stacked shim plates, the thickness of the first spacers 8a, 8b and the second spacers 9a, 9b can be easily changed by changing the number of stacked shim plates.

Since the rolling device 100 for manufacturing electric resistance welded steel pipes according to this embodiment has the above-mentioned preferred configuration, when the grooves of the upper grooved rolls 11, 21 removed from the upper housings 51, 61 are modified, the first spacers 8a, 8b are replaced with the first spacers 8a, 8b that are thicker (larger by the thickness corresponding to the amount of modification) than the thickness of the first spacers 8a, 8b attached before modification, and the upper grooved rolls 11, 21 after modification can be attached to the upper housings 51, 61 through the replaced first spacers 8a, 8b. As a result, the vertical (Z direction) positions of the upper grooved rolls 11, 21 (more precisely, positions along a direction perpendicular to the rotation center of the upper grooved rolls 11, 21) approach the center of the blank pipe P', and the grooves of the upper grooved rolls 11, 21 and the grooves of the lower grooved rolls 12, 22 are easily positioned on the same circumference, so that the effect of modifying the upper grooved rolls 11, 21 can be reduced.
In addition, when the grooves of the lower grooved rolls 12, 22 removed from the lower housings 52, 62 are reshaped, the second spacers 9a, 9b are replaced with second spacers having a smaller thickness (smaller by the thickness corresponding to the amount of reshaping) than the thickness of the second spacers 9a, 9b attached before reshaping, and the upper grooved rolls 11, 21 can be attached to the upper housings 51, 61 via the replaced second spacers 9a, 9b. This adjusts the horizontal (Y direction) position of the upper grooved rolls 11, 21 (more precisely, the position along the direction of the rotation center of the upper grooved rolls 11, 21), and the grooves of the upper grooved rolls 11, 21 and the grooves of the lower grooved rolls 12, 22 are easily positioned on the same circumference, thereby reducing the effect of reshaping the lower grooved rolls 12, 22. Thereafter, if necessary, the horizontal (Y direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2 can be reduced by the expansion/contraction means 3 (bringing the first grooved roll pair 1 and the second grooved roll pair 2 closer to each other) so that the diameters of the grooves of the first grooved roll pair 1 and the second grooved roll pair 2 match the outer diameter of the blank tube P'.

In this embodiment, a means capable of adjusting the position of the second grooved roll pair 2 in the vertical direction (Z direction) is exemplified as the lifting means 4, but the present invention is not limited to this, and it is also possible to use a means capable of adjusting the position of the first grooved roll pair 1 in the vertical direction (Z direction) as the lifting means.
In addition, the specific configurations of the expanding/contracting means 3 and the lifting/lowering means 4 described in this embodiment are merely examples, and the present invention is not limited thereto. As long as the horizontal (Y-direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2 can be adjusted, expanding/contracting means having various configurations can be adopted. In addition, as long as the vertical (Z-direction) separation distance between the first grooved roll pair 1 and the second grooved roll pair 2 can be adjusted, lifting/lowering means having various configurations can be adopted.

Reference Signs List 1: First pair of grooved rolls 2: Second pair of grooved rolls 3: Expanding/contracting means 4: Lifting means 5, 6: Housing 8a, 8b: First spacer 9a, 9b: Second spacer 11, 21: Upper grooved roll 12, 22: Lower grooved roll 51, 61: Upper housing 52, 62: Lower housing 100: Rolling device for electric resistance welded steel pipe P': Raw pipe P: Electric resistance welded steel pipe

Claims (4)

A rolling device for manufacturing electric resistance welded steel pipes, which manufactures electric resistance welded steel pipes by butting together heated edges of a mother pipe made of a plate material formed into a tubular shape, and welding the edges by pressure welding, comprises:
As a grooved roll,
a first pair of grooved rolls arranged on one side of the mother tube in a horizontal direction perpendicular to the longitudinal direction of the mother tube so as to surround an outer periphery of the mother tube, the first pair of grooved rolls being composed of a pair of upper and lower grooved rolls connected to each other;
a second pair of grooved rolls arranged on the other side of the mother tube in a horizontal direction perpendicular to the longitudinal direction of the mother tube so as to surround an outer periphery of the mother tube, the second pair of grooved rolls being composed of a pair of upper and lower grooved rolls connected to each other,
an expansion/contraction means capable of adjusting the horizontal separation distance between the first pair of grooved rolls and the second pair of grooved rolls;
Further provided with a lifting means capable of adjusting the vertical separation distance between the first grooved roll pair and the second grooved roll pair,
2. A rolling device for manufacturing electric resistance welded steel pipes. Each of the grooved rolls constituting the first grooved roll pair and the second grooved roll pair has a rotation center that is approximately perpendicular to the perpendicular line of the grooved profile passing through the midpoint of the arc-shaped grooved profile.
2. The rolling device for manufacturing electric resistance welded steel pipe according to claim 1. The upper grooved rolls constituting the first grooved roll pair and the second grooved roll pair each have a central angle of an arc-shaped groove profile of 40° to 50°.
3. The rolling device for producing electric resistance welded steel pipe according to claim 1 or 2. The upper grooved rolls constituting the first grooved roll pair and the second grooved roll pair are attached to an upper housing, and the lower grooved rolls constituting the first grooved roll pair and the second grooved roll pair are attached to a lower housing, and the upper housing and the lower housing are connected to each other, so that the upper grooved rolls and the lower grooved rolls constituting the first grooved roll pair and the second grooved roll pair are connected to each other,
the upper grooved roll is attached to the upper housing via a first spacer and a second spacer that are detachably attached to the upper housing,
The first spacer is attached to the upper housing so that the position of the upper grooved roll along a direction perpendicular to the center of rotation of the upper grooved roll is adjusted according to the thickness of the first spacer;
The second spacer is attached to the upper housing so that the position of the upper grooved roll along the direction of the center of rotation of the upper grooved roll is adjusted according to the thickness of the second spacer.
3. The rolling device for producing electric resistance welded steel pipe according to claim 1 or 2.

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