JPH08243645A - Split roll for manufacturing tube - Google Patents

Abstract

PURPOSE: To provide a split roll for manufacturing a tube appropriate for manufacturing a metallic tube free from surface flaws. CONSTITUTION: Flange parts 20, 30 on each side of a roll middle part 10 are split along the line D of division which crosses the line L which passes the center point C of the roll and is parallel to a shaft 40 at the angle θ of 20-40 pts.wt.. Roll bearings 11, 12 are provided between the roll middle part 10 and a shaft 40, ball bearings 21, 31 are provided between the flange parts 20, 30 and the shaft 40, and thrust roller bearings 22, 32 having bearing rings are provided between the roll middle part 10 and the flange parts 20, 30. The right and left flange parts 20, 30 can be integrated by being fixed to each end of a tube fitted to a shaft 40. Generation of surface flaws is suppressed by limiting the angle θ in the range of 20 and 40 deg., and the metallic tube of excellent appearance can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a split-type pipe-making roll used for producing a metal pipe by forming a metal strip into a predetermined shape.

[0002]

2. Description of the Related Art When manufacturing a welded pipe from a metal strip, the metal strip is curved in a width direction with a predetermined curvature, and both widthwise ends are welded. In the step of bending the metal strip, the pipe forming rolls provided in multiple stages are pressed against the surface of the metal strip. At this time, a surface flaw may occur on the metal strip, which is a pipe material, due to contact with the pipe forming roll. The surface flaw is caused by the friction generated between the roll and the pipe-forming material at the flange portion because the peripheral speed at the time of roll rotation is different between the roll hole type flange portion and the roll central portion. Surface defects reduce the quality of manufactured metal tubes and increase the percentage that cannot be shipped as products. Therefore, in order to eliminate surface flaws, various measures such as a method of partially polishing the pipe-making roll and a method of coating the hole surface of the split roll with a synthetic resin (see Japanese Utility Model Laid-Open No. 61-87613) have been taken. Has been taken.

[0003]

When partially polishing a pipe-making roll at a portion in contact with a portion of the pipe-forming material where defects are likely to occur, the contact of the pipe-making roll with the pipe-forming material becomes weak at the polishing portion. Therefore, the occurrence of surface defects is reduced. But,
While the contact at the polishing part is weakened, the contact at other parts except the polishing part is relatively stronger. As a result, surface flaws are more likely to occur in areas where the contact is strong, especially in the vicinity of the polished area. On the other hand, as disclosed in Japanese Utility Model Laid-Open No. 61-87613, in the split type roll in which the hole surface of the roll is covered with the synthetic resin, the flange portion having a different peripheral speed is directly in contact with the center portion of the roll, so that the smooth rotation can be achieved. Be hindered. As a result, the pipe material to be processed may be subjected to an irregular processing force, which may deteriorate the shape accuracy of the obtained metal pipe. The present invention has been devised to solve such a problem, and in a split type roll structure that reduces the peripheral speed difference, by regulating the split position and interposing a bearing, the flange portion and the roll center The object of the present invention is to avoid direct contact with the section and to enable smooth rotation of the pipe-making split roll.

[0004]

In order to achieve the object, the split roll for pipe making of the present invention has an angle of 20 to 40 degrees with respect to a line passing through the center point of an arc formed by the roll surface and parallel to the shaft. The flange parts on both sides are divided from the roll center part along the intersecting dividing line, and the roller bearing provided between the roll center part and the shaft, the ball bearing provided between the flange part and the shaft, and the roll center And a thrust roller bearing with a bearing ring provided between the shaft portion and the flange portion. Moreover, since the left and right flanges are synchronized, a roll structure in which the left and right flanges are integrated can be adopted. In this case, fix the flanges on both sides to both ends of the pipe fitted to the shaft,
A roller bearing is provided between the center of the roll and the pipe.

In the split roll for pipe making according to the present invention, for example, as shown in FIG. 1, flange portions 20 and 30 are separably combined on both sides of the roll central portion 10. In a state where the roll central portion 10 and the flange portions 20 and 30 are combined, an arc-shaped roll surface F having a radius from the center point C to the roll central portion 10 and the flange portions 20 and 30 is formed. Roll central part 10 and flange part 20,
30 is divided along a dividing line L that intersects a line L passing through the center point C and parallel to the shaft 40 at an angle θ. The intersection angle θ of the parting lines L needs to be in the range of 20 to 40 degrees in order to prevent surface flaws from being imparted to the pipe material to be produced. This angle has been clarified by investigations and studies by the present inventors, as will be apparent from the examples described later. If the crossing angle θ is too small, the peripheral speed difference between the end and the center in the central part of the roll becomes large, and surface defects occur. On the other hand, if the intersecting angle θ is too large, the peripheral speed difference between both ends of the flange portion, that is, the end portion near the center of the roll and the opposite side thereof becomes large in the flange portion, and similarly surface defects occur.

The roll central portion 10 is provided with a shaft 4 via roller bearings 11 and 12 provided on the roll central portion 10 side.
It is fitted with 0. The flange portions 20 and 30 are fitted to the shaft 40 via ball bearings 21 and 31 provided on the flange portions 20 and 30 side. Roller bearing 11,
12 and the ball bearings 21 and 31, the central portion 10 of the roll
Also, the flange portions 20 and 30 smoothly rotate around the shaft 40. In addition, the roll central portion 10 and the flange portion 2
The central roller portion 10 and the flange portions 20 and 30 are smoothly rotated with each other by the thrust roller bearings 22 and 32 with orbital rings provided between the roll central portion 10 and the flange portions 20 and 30.

Although the central portion 10 of the roll is opposed to the shaft 40 via the roller bearings 11 and 12 in FIG.
It is also possible to adopt the structure shown in FIG. In this case, the pipe 41 is fitted to the shaft 40 inside the roller bearings 11 and 12. The pipe 41 includes bolts 23,
Both ends are fixed to the flange portions 20 and 30 by 33, respectively. Since the left and right flange portions 20 and 30 are integrated by the pipe 41, they rotate in synchronization. As a result, the roll diameter at the time of pipe making becomes symmetrical,
A metal tube with good shape accuracy can be obtained. Further, the integrated flange portions 20 and 30 can be easily set on the shaft 40. The split roll for pipe making according to the present invention,
It can also be applied to fin pass rolls. The fin pass roll is a roll having fins that enter the gaps at both ends in the plate width direction of the metal strip formed into a cylindrical shape before welding. As shown in FIG. 3, the fin 50 has a protruding portion 51 that protrudes radially inward from the arc-shaped roll surface F and is integrated with the roll central portion 10. Then, the roller bearings 11 and 12 smoothly rotate around the shaft 40. The fin 50 is preferably made of a hard material because the edge of the metal band before welding hits the fin 50.

[0008]

[Example] Stainless steel strip SUS30 having a plate thickness of 0.6 mm
The split fin-pass roll shown in FIG. 3 was used in a line for producing a steel pipe having a diameter of 60 mm from 4 at a pipe forming speed of 1.5 m / min. As the material of the roll, the central portion of the roll 10
A Cu alloy and cast nylon were used for both the flange portions 20 and 30, and a hardened material of the tool steel SKD11 was used for the fins 50. Roll central part 10 to flange parts 20, 3
The effect of the intersecting angle θ on the occurrence of surface flaws was investigated by using a dividing roll in which the intersecting angle θ with respect to the line L of the dividing line D where 0 is divided was variously changed. The surface flaws are visually observed on the roll-formed pipe, and those with no surface flaws are marked with ◯, those with weak surface flaws that are not problematic in terms of quality are marked with △, and there are problems in terms of quality. The case where the surface flaw was generated was evaluated as x.

[0009]

[Table 1]

As is apparent from Table 1, with the Cu alloy roll, when the crossing angle θ was maintained in the range of 20 to 40 degrees, a metal tube having a weak surface flaw and excellent quality was obtained.
However, when the intersecting angle θ was 10 degrees or 50 degrees, even with the same Cu alloy roll, surface defects were strong and the proportion of defective metal tubes increased. The cast nylon roll produced weak surface flaws when the crossing angle θ was 10 degrees or 50 degrees, but at the crossing angle θ of 20 to 40 degrees, a good metal tube having no surface flaws was manufactured. The influence of the intersection angle θ on the occurrence of surface flaws is the same when the pipe is made from ferritic stainless steel or ordinary steel, and a steel pipe having a good surface condition was produced at the intersection angle θ of 20 to 40 degrees. .
As can be seen from Table 1, when compared with the Cu alloy roll, it can be seen that cast nylon is desirable as the roll material. However, the rolls placed immediately after welding are
The cast nylon may be melted by the radiant heat from the high-temperature weld, and it is necessary to use a metal roll. Therefore, in this case, only the roll central portion 10 and the flange portions 20 and 30 which are in contact with the welded portion are made of Cu alloy rolls, and the other portions are made of cast nylon. As a result, surface defects can be eliminated to the extent that there is no problem in appearance, and a metal tube having a good surface condition can be manufactured.

[0011]

As described above, the split roll for pipe making according to the present invention divides the flange portion from the roll central portion along the split line inclined at a predetermined angle from the center point of the roll surface and rolls. A bearing is interposed between the central portion, the flange portion and the shaft. As a result, the center part of the roll and the flange part rotate independently of each other and smoothly, and the metal band, which is the pipe material to be formed, is not scratched. As a result, a metal tube having an excellent surface condition is manufactured. Further, since it is of a split type, it can be easily attached to and replaced with the shaft, and it becomes possible to manufacture metal tubes having various sizes simply by exchanging the central portion of the roll and the flange portion.

[Brief description of drawings]

FIG. 1 shows an example of a split roll for pipe making according to the present invention.

[Fig. 2] Pipe-making split roll in which a flange is integrated with a pipe

[Fig. 3] Pipe-forming split roll with fins

[Explanation of symbols]

10: Roll central part 11, 12: Roller bearing 20, 30: Flange part 21, 31: Ball bearing
22, 32: Thrust roller bearing with bearing ring 23,
33: Bolt 40: Shaft 41: Pipe that integrates the flanges 20 and 30 50: Fin 51: Projection F: Roll surface C: Center point of arc formed by roll surface L: Shaft 40 passing through center point C Parallel lines
D: Dividing line θ: Angle at which the dividing line D intersects the line L

Claims (2)

[Claims] 1. A flange portion on both sides is divided from a central portion of a roll along a dividing line intersecting a line parallel to the shaft passing through a center point of an arc formed by the roll surface at an angle of 20 to 40 degrees. A roller bearing provided between the roll central portion and the shaft, a ball bearing provided between the flange portion and the shaft, and a thrust roller bearing with a bearing ring provided between the roll central portion and the flange portion. Split roll for pipe making. 2. The flange portions on both sides are divided from the central portion of the roll along a dividing line intersecting a line parallel to the shaft passing through the center point of the arc formed by the roll surface at an angle of 20 to 40 degrees. , The flange parts on both sides are fixed to both ends of the pipe fitted to the shaft, and the roller bearing provided between the roll central part and the pipe, the ball bearing provided between the flange part and the shaft, and the roll central part. A split roll for pipe making, which comprises a thrust roller bearing with a bearing ring provided between the flange part and the flange part.