JP2016163913A - Cutting device of pipe end internal face and cutting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting device 1 of a pipe end internal face which can perform cutting following a shape of an internal face in order to remove a scratch of a pipe internal face (in particular, a scratch of the pipe end internal face), and a cutting method.SOLUTION: A cutting edge 4, a first copying roller 11 and a second copying roller 12 are arranged at a cutting head 3, a first copying roller 11 is arranged ahead of the cutting edge 4 in a progressing direction, the second copying roller 12 is arranged reward of the cutting edge 4 in the progressing direction, the first copying roller 11 contacts with a pipe end internal face while extruding the cutting head 3 to a vertical direction with respect to a pipe axis of a steel pipe 2 by the hydraulic pressure of a working fluid, the cutting edges 4 cuts the pipe end internal face by copying the first copying roller 11 while moving in the steel pipe 2, and after the first copying roller 11 is extruded to the outside of the pipe from a pipe end opening part, the cutting edge 4 cuts the pipe end internal face while copying the second copying roller 12.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cutting apparatus and a cutting method for cutting an inner surface of an end portion of a steel pipe used as a line pipe.

  Seamless steel pipes are manufactured hot by heating the billet, which is the material, so that inner surface defects (so-called inner surface pits) generated by the biting of the oxide scale and inner surface defects caused by zaku generated during the casting of the material (So-called internal fogging) is likely to occur. In order to remove the inner surface flaws, a cutting apparatus for cutting the inner surface of the pipe has been studied.

  For example, Patent Document 1 discloses a cutting device in which a copying roller is disposed in front of a cutting blade in a cutting progress direction. This technique cuts the inner surface of the tube by moving the cutting device from the tube center side to the tube end side while copying the inner surface of the tube with a copying roller. However, after the copying roller is pulled out from the tube end opening, cutting of the inner surface of the tube end by the cutting blade is continued, but it is inevitable that the cutting amount becomes unstable. As a result, there arises a problem that the inner surface flaw at the tube end cannot be sufficiently removed.

JP 2014-184497 A

  The present invention eliminates the problems of the prior art and allows the pipe end to be cut according to the shape of the inner surface in order to remove the inner surface flaw of the pipe (particularly the inner flaw of the pipe end). An object of the present invention is to provide an inner surface cutting device and a cutting method.

  The inventor of the present invention paid attention to the fact that by following the inner surface of the steel pipe while making a copying roller follow the cutting process, it is possible to perform the cutting process following the shape of the inner surface and to remove the inner surface flaws. Then, the technique for performing the cutting process by arranging the copying roller and the cutting blade inside the steel pipe was examined in detail, and the following knowledge was obtained.

  In order to precisely cut the inner surface of the pipe end by rotating the copying roller and the cutting blade inside the steel pipe and moving from the pipe center side to the pipe end side, the copying roller is moved forward in the traveling direction of the cutting blade. Must be provided. Even after the copying roller exits from the pipe end opening to the outside of the steel pipe, it is necessary to dispose the copying roller also behind the cutting blade in order to follow the shape of the inner surface. is there.

  The present invention has been made based on such knowledge.

  That is, the present invention is a cutting device that rotates while moving the inside of a steel pipe from the pipe center side to the pipe end side to cut the inner surface of the pipe end, and includes a cutting blade that cuts the inner surface of the pipe end, A cutting head having a first scanning roller disposed forward in the traveling direction and a second scanning roller disposed backward in the traveling direction of the cutting blade, and the cutting head with respect to the tube axis of the steel pipe A hydraulic pressure hole that fills the hydraulic oil to be pushed out in the vertical direction, a hydraulic pressure adjustment spring that is arranged in the center of the pipe of the hydraulic pressure hole and adjusts the hydraulic pressure generated by the hydraulic oil, and rotates the cutting head within the steel pipe And a cutting drive shaft that moves to the pipe end opening, and a cutting device for the inner surface of the pipe end that provides a hydraulic oil passage for supplying hydraulic oil to the hydraulic pressure application hole inside the cutting drive shaft. .

  In the cutting apparatus of the present invention, when the first copying roller is in contact with the inner surface of the pipe end portion, it is preferable that the cutting device is arranged so that a gap is formed between the second copying roller and the inner surface of the tube end portion. Furthermore, it is preferable to provide an inclined surface or a curved surface at the corner portion of the first copying roller close to the cutting blade.

  According to another aspect of the present invention, there is provided a cutting method in which the cutting head is rotated from the center of the pipe to the pipe end side while rotating the cutting head inside the steel pipe to cut the inner surface of the pipe end. A scanning roller, a first scanning roller disposed in front of the cutting blade in the traveling direction, and a second scanning roller disposed in the rear of the cutting blade in the traveling direction. While the first scanning roller contacts the inner surface of the pipe end and moves in the steel pipe while extruding in a direction perpendicular to the tube axis, the cutting blade cuts the inner surface of the pipe end along the first scanning roller, This is a method of cutting the inner surface of the tube end portion in which the cutting blade cuts the inner surface of the tube end portion following the second scanning roller after the first copying roller has moved out of the tube through the tube end opening.

  In the cutting method of the present invention, while the first copying roller moves in the steel pipe, the first copying roller is brought into contact with the inner surface of the tube end portion, and a gap is formed between the second copying roller and the inner surface of the tube end portion. It is preferable to arrange so as to occur. Furthermore, it is preferable that the corner portion of the first copying roller closer to the cutting blade is an inclined surface or a curved surface.

  According to the present invention, cutting can be performed following the shape of the inner surface of the pipe end portion, so that it is possible to remove the inner surface flaws of the pipe end portion, and there is a remarkable industrial effect.

FIG. 4 is a cross-sectional view schematically showing an example in which the first copying roller moves in the steel pipe while being in contact with the inner surface of the pipe end when the inner surface of the pipe end is cut by applying the present invention. FIG. 5 is a cross-sectional view schematically showing an example in which the first copying roller comes out of the pipe end opening when the inner surface of the pipe end is cut by applying the present invention.

  FIG. 1 is a cross-sectional view schematically showing an example in which the first copying roller 11 moves in the steel pipe 2 while being in contact with the inner surface of the pipe end when the inner surface of the pipe end is cut by applying the present invention. It is. An arrow A in FIG. 1 indicates the traveling direction of the cutting device 1.

  The cutting apparatus 1 according to the present invention has a cutting head 3. The cutting head 3 includes a cutting blade 4. A first scanning roller 11 is disposed in front of the cutting blade 4 in the moving direction (that is, the pipe end surface 10 side), and a second scanning roller 12 is positioned behind the cutting blade 4 in the moving direction. Place. Then, the first copying roller 11 comes into contact with the inner surface of the tube end portion and moves from the tube center side to the tube end side while being rotated by the driving force transmitted through the cutting drive shaft 8 (arrow A).

  The cutting device 1 has a hydraulic pressure application hole 5 therein, and hydraulic oil is supplied to the hydraulic pressure application hole 5 through a hydraulic oil flow path 9 in the cutting drive shaft 8. Then, the cutting head 3 is pushed out in the direction perpendicular to the tube axis of the steel pipe 2 by the hydraulic pressure of the hydraulic oil that fills the hydraulic pressure application hole 5 (arrow B). A hydraulic pressure adjusting spring 6 is disposed on the center side of the pipe of the hydraulic pressure applying hole 5, and the hydraulic pressure adjusting spring 6 slides the hydraulic pressure adjusting fitting 7 (arrow C). That is, by sliding the hydraulic adjustment fitting 7 with the elastic force of the hydraulic adjustment spring 6, the size of the hydraulic pressure applying hole 5 is changed, and the hydraulic pressure of the hydraulic oil is adjusted.

  In this way, the first copying roller 11 can follow the shape of the inner surface of the tube end portion, and the cutting blade 4 cuts the inner surface of the tube end portion.

  The second copying roller 12 may come into contact with the inner surface of the pipe end together with the first copying roller 11, but as shown in FIG. 1, from the viewpoint of preventing the scratch on the inner surface of the tube end and reducing the load on the cutting drive shaft 8. In addition, it is preferable to arrange so that a gap G is formed between the inner surface of the tube end portion.

  Then, the cutting device 1 moves in the direction of the arrow A, and the first copying roller 11 comes out of the steel pipe 2 from the pipe end opening. An example is shown in FIG.

  At that time, since there is a gap G between the second scanning roller 12 and the inner surface of the pipe end, the cutting head 3 is pushed out in the direction perpendicular to the pipe axis by the hydraulic pressure of the hydraulic oil in the hydraulic pressure application hole 5. Move in the direction of arrow A. As a result, the thickness of the pipe end portion is reduced, and the amount of reduction corresponds to the gap G. After the second scanning roller 12 comes into contact with the inner surface of the tube end, the second scanning roller 12 can follow the inner surface of the tube end, and the cutting blade 4 cuts the inner surface of the tube end to the tube end surface 10. Go.

  That is, the thickness corresponding to the gap G decreases in the thickness of the pipe end, but if the gap G is set within the thickness tolerance range, the change in the thickness of the pipe end does not become a problem.

  Further, it is possible to prevent the oil pressure of the oil pressure applying hole 5 from changing suddenly until the second copying roller 12 comes into contact with the inner surface of the pipe end after the first copying roller 11 comes out of the steel pipe 2. Therefore, it is preferable to provide an inclined surface or a curved surface at the corner portion of the first copying roller 11 on the side close to the cutting blade 4.

  However, if the gap G shown in FIG. 1 is not provided and both the first copying roller 11 and the second copying roller 12 are arranged so as to contact the inner surface of the tube end portion, the thickness of the tube end portion does not change.

  The second copying roller 12 is not necessarily a rotating body, and may be configured to slide along the inner surface of the pipe end (for example, a shoe). However, the rotating body (that is, the second scanning roller 12) is preferable from the viewpoint of preventing the scratch on the inner surface of the pipe end and reducing the load on the cutting drive shaft 8.

  1 and 2 show an example in which two cutting heads 3 are arranged in the cutting apparatus 1, but the number of cutting heads 3 is not limited. However, it is preferable to arrange two or more cutting heads 3 because the inner surface of the pipe end can be stably cut. In that case, the cutting heads 3 are arranged at equal intervals in the pipe circumferential direction. For example, two cutting heads 3 are arranged at 180 ° intervals, three cutting heads 3 at 120 ° intervals, and four cutting heads 3 at 90 ° intervals. Further, when the number of cutting heads 3 is one, it is preferable to arrange an auxiliary roller (not shown) at a position 180 ° from the cutting head 3 in order to stabilize the rotation of the cutting device 1.

  By applying the present invention, the inner surface of the end of the seamless steel pipe was cut. The procedure will be described.

  As shown in FIGS. 1 and 2, the inner surface of the pipe end portion was cut using a cutting device 1 provided with two cutting heads 3 at 180 ° intervals. The gap G in FIG. 1 was 20 mm. This gap G is a value that satisfies the thickness tolerance of the line pipe defined in the API standard. In addition, an inclined surface is provided at a corner portion of the first copying roller 11 on the side close to the cutting blade 4. The inclination angle of the inclined surface with respect to the tube axis was 45 °.

  After cutting the inner surface of the tube end portion in this manner, the presence or absence of the inner surface flaw was inspected. As a result, no inner surface flaw was found.

DESCRIPTION OF SYMBOLS 1 Cutting device 2 Steel pipe 3 Cutting head 4 Cutting blade 5 Oil pressure imparting hole 6 Oil pressure adjusting spring 7 Oil pressure adjusting metal fitting 8 Cutting drive shaft 9 Hydraulic oil flow path
10 Pipe end face
11 First copying roller
12 Second copying roller

Claims (6)

  A cutting device that rotates while moving the inside of a steel pipe from the pipe center side to the pipe end side to cut the inner surface of the pipe end, the cutting blade for cutting the inner face of the pipe end, and the forward direction of the cutting blade And a second scanning roller disposed behind the cutting blade in the advancing direction, and the cutting head with respect to the tube axis of the steel pipe. A hydraulic pressure application hole for filling the hydraulic oil to be pushed out in the vertical direction, a hydraulic pressure adjustment spring disposed on the center side of the pipe of the hydraulic pressure application hole to adjust the hydraulic pressure generated by the hydraulic oil, and the cutting head in the steel pipe A cutting drive shaft that is moved to the tube end opening while being rotated at a position, and a working oil flow path for supplying the working oil to the oil pressure applying hole is provided inside the cutting drive shaft. Cutting device for inner surface of pipe end.   2. The device according to claim 1, wherein when the first copying roller is in contact with the inner surface of the tube end portion, the first copying roller is disposed so that a gap is formed between the second copying roller and the inner surface of the tube end portion. The cutting apparatus of the pipe end part inner surface as described.   3. The cutting device for an inner surface of a pipe end according to claim 1, wherein an inclined surface or a curved surface is provided at a corner portion of the first copying roller close to the cutting blade.   In a cutting method of cutting a pipe end inner surface by moving from a pipe center side to a pipe end side while rotating a cutting head inside a steel pipe, a cutting blade, a first copying roller, and a second copying roller are attached to the cutting head. The first scanning roller is disposed in front of the cutting blade in the traveling direction, the second scanning roller is disposed in the rear of the cutting blade in the traveling direction, and the cutting head is moved to the steel pipe by hydraulic oil pressure. While the first scanning roller contacts the inner surface of the tube end and moves in the steel pipe while being extruded in a direction perpendicular to the tube axis of the tube, the cutting blade follows the first scanning roller to move the tube end. The inner surface of the tube end is cut, and after the first scanning roller comes out of the tube end opening, the cutting blade cuts the inner surface of the tube end portion following the second scanning roller. Cutting method for the inner surface of the pipe end.   While the first copying roller moves in the steel pipe, the first copying roller is brought into contact with the inner surface of the tube end portion, and a gap is formed between the second copying roller and the inner surface of the tube end portion. It arrange | positions, The cutting method of the pipe end part inner surface of Claim 4 characterized by the above-mentioned.   6. The method for cutting an inner surface of a pipe end according to claim 4 or 5, wherein a corner of the first copying roller closer to the cutting blade is an inclined surface or a curved surface.

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