JP2014182048A - Method and device for measuring pipe thickness of metal pipe during bending processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for measuring a pipe thickness of the back face of a pipe during bending processing, achieving highly efficient inspection work, easy to handle, and low in cost.SOLUTION: A method for bending a metal pipe 1 includes: making a narrow region in the longitudinal direction of a metal pipe pass through a heating/cooling device for heating and cooling; clamping a tip end side of the metal pipe to be processed to a rotatable bending arm 3; deforming the metal pipe 1 by propelling it in the longitudinal direction while heating it by the heating/cooling device; and cooling a part of the metal pipe 1 just after being heated and deformed. In this method, a case accommodating a probe of an ultrasonic thickness gauge of a device for measuring the pipe thickness of the metal pipe is disposed in the vicinity of a water cooling line which is a contact point between cooling water 8 and the metal pipe in the cooling part so as to be movable in a direction perpendicular to a bending center o of the metal pipe, the case is pushed onto the back face of the metal pile by driving a driving device, as necessary, a preset clearance is formed between the probe and a surface of the metal pipe so that the cooling water can pass through the clearance, and the pipe thickness of the metal pile is measured by utilizing the cooling water as a contact medium.

Description

  The present invention relates to a method and apparatus for measuring the thickness of a metal tube during bending, and more particularly to a method and apparatus for measuring the thickness of the back surface of a metal tube online.

  The construction of energy plants such as petrochemical plants and garbage treatment plants has been actively carried out, and metal pipes, including bent pipes obtained by bending straight pipes, are often used as pipes for transporting various fluids. Since then, the manufacturing technology for bending pipes is progressing steadily, such as the development of technology to reduce the rate of thinning.

  On the other hand, the technology to measure the thickness of the back surface of a metal tube that guarantees the quality of the bent tube is to place the bent tube from the bending machine on the inspection platen, and plot using a chalk or the like at the determined measurement point A method is used in which an inspector manually measures the measurement point using an ultrasonic thickness gauge and records the data in an inspection table. The invention described in Patent Document 1 shows that a non-destructive inspection is easily performed in a short time on a bend portion of a small-diameter pipe.

JP 2007-212406 A

In the invention of the nondestructive inspection jig and the ultrasonic nondestructive inspection apparatus described in Patent Document 1, both ends of the bend part are fixed in FIG. 9 of Patent Document 1, and the probe is attached to the bend part. It is shown that non-destructive inspection is performed on the entire area by sliding and scanning in the longitudinal direction of the outer peripheral surface on the back side. Since these are methods for manually or automatically measuring the bending pipe offline, it is not possible to measure the thickness of the back side of the bending pipe online during bending.
The present invention has been made in view of such circumstances, and its purpose is to increase the efficiency of the inspection work by bringing the measurement of the tube thickness of the back surface of the metal tube being bent online. It is an object of the present invention to provide a method and apparatus for measuring the thickness of the back surface of a metal tube during bending which is easy to handle and inexpensive.

As a result of intensive studies on the above problems, the present inventors have obtained the following knowledge.
That is, in a bending method of a metal tube in which a bending moment is applied to the heated portion of the metal tube to deform and the portion immediately after that is cooled, the water cooling that is a contact point between the cooling water of the cooling portion and the metal tube A case containing an ultrasonic thickness gauge probe for measuring the thickness of a metal tube in the vicinity of the wire is arranged so that it can be moved vertically to the bending center o of the metal tube, and the case is necessary. The driving device is driven in accordance with the pressure and pressed against the back surface of the metal tube to form a preset gap between the probe and the surface of the metal tube so that the cooling water can pass through the gap. Thus, it has been found that the thickness of the back surface of the metal tube can be measured using the cooling water as a contact medium.

  The invention of claim 1 of the present application is based on the above knowledge.

An apparatus for measuring the thickness of a metal tube for carrying out the invention of claim 1 has the following configuration.
That is, a cooling water in a cooling portion of a metal pipe being bent, a probe for measuring a pipe thickness in the vicinity of a water cooling line that is a contact point of the metal pipe, a case housing the probe, the probe, and the probe A set bolt that locks after adjusting the gap with the surface of the metal tube, a roller that is attached to the case to ensure the gap between the probe and the surface of the metal tube, and the case and the metal tube It is characterized by comprising a drive device that drives and varies the distance to the surface.

The basic measurement principle of the invention of claim 1 will be described.
FIG. 1 is a diagram for explaining the basic principle of the present invention. FIG. 1 is an enlarged view of the lower side from AA in the front view of FIG. It is a figure which shows the state which pressed the apparatus which measures this.
In order to measure the thickness of the back surface of the bent portion of the metal pipe being bent, the case 103 containing the probe 101 of the apparatus 100 for measuring the thickness of the metal pipe is used as the bending center of the metal pipe using the driving device 102. It is a figure which shows the state set to the vicinity of the water cooling line which is driven to o direction, and is the contact point of the cooling water 8 of the cooling part, and the metal tube 2, and is between the surface of the probe 101 and the metal tube 2 at this time In order to maintain an appropriate gap g, a set bolt 105 is used to adjust in advance, and the cooling water 8 passing through the gap g is used as a contact medium as indicated by hatching.
Further, in order to keep the gap g between the probe 101 and the surface of the metal tube 2 constant, the driving device 102 is used to press the roller 104 until it contacts the surface of the metal tube 2.

The drive device means an air cylinder, a hydraulic cylinder, an electric motor or the like, and this figure is a case of an air cylinder.
Further, the drive device has a case detent function (not shown).

  FIG. 2 shows an apparatus 100 for measuring the thickness of a metal pipe, which is arranged to be driven in the direction of the bending center o of the metal pipe.

  By using the method and apparatus for measuring the thickness of a metal tube according to the present invention, the measurement of the thickness of the back surface of the metal tube during bending can be made online, which can contribute to the improvement of productivity.

FIG. 1 is a diagram for explaining the basic principle of the present invention, and is an enlarged view of the lower side from AA in the front view of FIG. FIG. 2 shows an apparatus for measuring the thickness of a metal tube. FIG. 3 is an explanatory diagram for carrying out the present invention according to claim 1 of the present invention.

Embodiment for Implementing Claim 1 of the Present Embodiment Embodiment 1
FIG. 3 is an explanatory diagram for carrying out the present invention of claim 1 of the present application.
FIG. 3A is a view showing a relative position between a bending machine in a bending standby state and an apparatus 100 for measuring the thickness of a metal pipe.
FIG. 3B is a diagram during the bending process. A case 103 in which the probe 101 of the apparatus 100 for measuring the thickness of the metal tube is accommodated on the back surface of the metal tube 2 is connected to the metal tube using the driving device 102. It is a figure which shows the state pressed until the roller 104 contacted to the vicinity of the water cooling line which is driven in the direction of the bending center o, and the cooling water 8 of the cooling part and the metal tube 2 contact point.
At this time, an appropriate gap g is maintained between the probe 101 and the surface of the metal tube 2 in advance, and the cooling water 8 passing through the gap g is used as a contact medium. .
The measured value of the thickness of the metal tube is sent to the recorder 9 and recorded together with the output signal t of the thickness converter 6 and the output signal θ of the arm turning angle detector 5.
The measured value t of the thickness of the metal tube is recorded on the recorder 9 online at an arbitrarily set turning angle pitch with the turning angle θ as a parameter.

In order to measure on-line using a device that measures the tube thickness, prepare test specimens of the same material as the metal tube with a thickness of 10, 8, or 6 mm, and the gap between the surface of the probe and the test specimen for calibration. Was set to within 0.5 mm, calibration was performed while water was flowing through the gap, and the tube thickness was set to be displayed thinly in consideration of the temperature of the metal tube during online measurement.
Further, using a sample of a bending tube having the same bending radius as that of the metal tube to be measured, the gap g between the surface of the probe and the metal tube was set within 0.5 mm.

Example 1
An embodiment when applied to actual bending will be described.
In the apparatus configuration shown in FIG. 3, the steel material STPG 38 has dimensions of an outer diameter of 165.2 mm, a tube thickness of 9.3 mm, a bending radius R of 800 mm, a bending angle of 90 °, and a bending portion heating temperature of 950 ° C. The tube thickness on the back surface of the metal tube is as follows when measured on-line using the apparatus 100 for measuring the tube thickness and when measured by an inspector manually using an ultrasonic thickness meter: Met.
The measurement of the thickness of the metal tube during bending was expected to reduce the thickness of the back surface of the metal tube by about 10% due to this bending, so the thickness of the back surface of the metal tube was about 8.5 mm. After calibrating using an 8 mm calibration test piece, the back of 5 locations at 10 °, 25 °, 45 °, 65 °, and 80 ° from the boundary between the straight tube and the bent tube at the beginning of bending. The tube thickness was measured online using an apparatus 100 for measuring the tube thickness of metal tubes.
The thickness of the metal tube after processing is measured on the inspection platen in the same way as on-line measurement, 5 ° from the boundary between the straight pipe and the bent pipe at the beginning of bending, 10 °, 25 °, 45 °, 65 °, 80 °. The inspector manually measured the thickness of the back tube at the location using an ultrasonic thickness gauge.
Comparative data is shown in Table 1.

Results From the above results, when measured online using the apparatus 100 for measuring tube thickness and when measured manually using an ultrasonic thickness gauge, the one measured online is displayed lighter. However, it was confirmed that there was not much difference.

Example 2
An embodiment in which the same metal tube as in Embodiment 1 is applied to different bending radii will be described.
In the apparatus configuration shown in FIG. 3, STPG 38 of steel material, dimensions are outer diameter 165.2 mm, tube thickness 9.3 mm, bending radius R is 400 mm, bending angle 90 °, and bending temperature is 950 ° C. The tube thickness on the back surface of the metal tube is as follows when the case where the thickness is measured online using the apparatus 100 for measuring the tube thickness and the case where the inspector manually measures using the ultrasonic thickness meter is as follows. there were.
In addition, the measurement of the thickness of the metal pipe during the bending process was expected to reduce the thickness of the back of the metal pipe by about 15% due to this bending, so the thickness of the back of the metal pipe would be about 8 mm. After calibrating using an 8 mm calibration test piece, the back tube thicknesses at five locations of 10 °, 25 °, 45 °, 65 °, and 80 ° from the boundary between the straight pipe at the beginning of bending and the bent pipe Was measured online using an apparatus 100 for measuring the thickness of a metal tube.
The thickness of the metal tube after processing is measured on the inspection platen in the same way as on-line measurement, 5 ° from the boundary between the straight pipe and the bent pipe at the beginning of bending, 10 °, 25 °, 45 °, 65 °, 80 °. The inspector manually measured the thickness of the back tube at the location using an ultrasonic thickness gauge.
Comparative data is shown in Table 2.

Results From the above results, when measured online using the apparatus 100 for measuring tube thickness and when measured manually using an ultrasonic thickness gauge, the one measured online is displayed lighter. However, it was confirmed that there was not much difference.

Example 3
An embodiment when applied to different outer diameters and bending radii of metal pipes in actual bending will be described.
In the apparatus configuration shown in FIG. 3, STPG 38 of steel material, dimensions are outer diameter 139.8 mm, tube thickness 7.1 mm, bending radius R is 600 mm, bending angle 90 °, and bending temperature is 950 ° C. The tube thickness on the back surface of the metal tube is as follows when the case where the thickness is measured online using the apparatus 100 for measuring the tube thickness and the case where the inspector manually measures using the ultrasonic thickness meter is as follows. there were.
The measurement of the thickness of the metal pipe during bending was expected to reduce the thickness of the back of the metal pipe by about 10% due to this bending, so the thickness of the back of the metal pipe was about 6.5 mm. After calibrating using a 6 mm calibration test piece, the back of the five straight sections at 10 °, 25 °, 45 °, 65 °, and 80 ° from the boundary between the straight tube and the bent tube at the beginning of bending. The tube thickness was measured online using a device 100 that measures the tube thickness of a metal tube.
The thickness of the metal tube after processing is measured on the inspection platen in the same way as on-line measurement, 5 ° from the boundary between the straight pipe and the bent pipe at the beginning of bending, 10 °, 25 °, 45 °, 65 °, 80 °. The inspector manually measured the thickness of the back tube at the location using an ultrasonic thickness gauge.
Comparative data is shown in Table 3.

Results From the above results, when measured online using the apparatus 100 for measuring tube thickness and when measured manually using an ultrasonic thickness gauge, the one measured online is displayed lighter. However, it was confirmed that there was not much difference.

Example 4
An embodiment in which the same metal tube as that in Embodiment 3 is applied to different bending radii will be described.
In the apparatus configuration shown in FIG. 3, STPG 38 of steel material, dimensions are outer diameter 139.8 mm, tube thickness 7.1 mm, bending radius R is 300 mm, bending angle 90 °, and bending temperature is 950 ° C. The tube thickness on the back surface of the metal tube is as follows when the case where the thickness is measured online using the apparatus 100 for measuring the tube thickness and the case where the inspector manually measures using the ultrasonic thickness meter is as follows. there were.
In addition, the measurement of the thickness of the metal tube during bending was expected to reduce the thickness of the back surface of the metal tube by about 20% due to this bending, so the thickness of the back surface of the metal tube would be about 6 mm. After calibrating using a 6 mm calibration specimen, the back tube thicknesses at five locations of 10 °, 25 °, 45 °, 65 °, and 80 ° from the boundary between the straight pipe at the beginning of bending and the bent pipe Was measured online using an apparatus 100 for measuring the thickness of a metal tube.
The thickness of the metal tube after processing is measured on the inspection platen in the same way as on-line measurement, 5 ° from the boundary between the straight pipe and the bent pipe at the beginning of bending, 10 °, 25 °, 45 °, 65 °, 80 °. The inspector manually measured the thickness of the back tube at the location using an ultrasonic thickness gauge.
Table 4 shows the comparison data.

Results From the above results, when measured online using the apparatus 100 for measuring tube thickness and when measured manually using an ultrasonic thickness gauge, the one measured online is displayed lighter. However, it was confirmed that there was not much difference.

DESCRIPTION OF SYMBOLS 1 Metal tube 2 Bent part 3 Metal tube Bending arm 4 Rotating shaft 5 Rotating angle detector 6 Thickness converter 7 Heating / cooling coil 8 Cooling water 9 Recorder 100 Device 101 for measuring the thickness of the metal tube 101 Probe 102 Air cylinder 103 Case 104 Roller 105 Set bolt V Metal tube travel direction R Bending radius o Bending center t Thickness signal θ Angle signal g Clearance between metal tube surface and probe

Claims (2)

  The metal tube to be bent is passed through a heating / cooling device that heats and cools the narrow region in the longitudinal direction, the processing tip side is clamped to a rotatable bending arm, and the metal tube is heated by the heating / cooling device. In the bending method of the metal tube, which is deformed by applying a bending moment to the heated portion by propelling in the longitudinal direction and cooling the portion immediately thereafter, the contact point between the cooling water of the cooling portion and the metal tube A case containing an ultrasonic thickness gauge probe of a device for measuring the thickness of a metal tube is disposed in the vicinity of the water cooling line, so that the case can be moved vertically to the bending center of the metal tube, If necessary, the case is driven and driven against the back surface of the metal tube to form a predetermined gap between the probe and the surface of the metal tube, and the cooling water passes through the gap. The cooling water can be used as a contact medium Method for measuring the tube thickness of the metal tube during bending and measuring the tube thickness of the metal pipe by use. A probe for measuring the thickness of the metal tube in the vicinity of the water-cooled wire being bent, a case housing the probe, a set bolt that locks after adjusting the gap between the probe and the metal tube, and A bending comprising: a roller attached to the case for ensuring a constant gap between the probe and the metal tube; and a driving device that drives and varies the distance between the case and the metal tube. A device that measures the thickness of metal pipes during processing.

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