JP3209475B2 - Measuring method of bead cutting shape on inner surface of ERW pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the inner cut shape of an electric resistance welded pipe obtained by cutting a butt weld along a pipe axis direction with a bead cutter or the like using an ultrasonic wave.

[0002]

2. Description of the Related Art Techniques for measuring the wall thickness of a pipe using ultrasonic waves have already been put to practical use. In addition, many techniques using ultrasonic waves for measuring the inner surface cut shape of a welded portion of an electric resistance welded pipe have been proposed in the past (for example, Japanese Patent Application Laid-Open No. 54-21372).
JP, JP-A-56-35057, JP-A-61-35057
273273, JP-A-2-20055).

[0003] The methods disclosed in these publications, the thickness measuring method both using ultrasound, i.e. FIG. 8 (a)
As shown in (b), the time t between the outer surface reflected wave S and the inner surface reflected wave B when the ultrasonic wave is vertically incident from the outer peripheral side of the electric resistance welded tube 1 is measured, and is expressed as ×× C × The inner profile is to be obtained by t (C is the sound speed in steel). 8 (a) is an ultrasonic probe, and FIG.
T in 8 (b) indicates a transmission wave.

[0004]

However, in any of the methods disclosed in these publications, the shape of the outer surface deviates from a perfect circle, or the end of the outer surface cutting portion is sharp (hereinafter, referred to as "external cutting edge portion"). ) for the lead to electric-resistance-welded pipe, so can not be stably outer surface reflected wave S and internally reflected wave B at that portion, if good inner surface bead cutting shape as shown in FIG. 8 (a) even, becomes poor thickness of the inner surface profile display as shown in FIG. 8 (c), the acceptance determination problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problem in the conventional method of measuring the inner cut shape of a welded portion of an electric resistance welded pipe using ultrasonic waves, and the outer shape is smaller than a perfect circle. It is an object of the present invention to provide a method for measuring the inner bead cutting shape of an ERW pipe, which can measure the inner cutting shape well even for an ERW pipe having a detached edge or an externally cut edge portion.

[0006]

In order to achieve the above-mentioned object, a method for measuring the bead cutting shape on the inner surface of an electric resistance welded pipe according to the present invention comprises the steps of : In a method for measuring the inner surface cut shape of an ERW pipe cut with a bead cutter or the like using ultrasonic waves, the ultrasonic waves are vertically incident from the outer peripheral side of the ERW pipe to be measured, including the welded portion. After detecting the inner and outer surface reflection echo positions during scanning in the circumferential direction of the tube, profile processing of the inner and outer surfaces is performed from these detected positions, and the average value of the outer surface profile in the base material portion is obtained. An allowance width is provided, and the shape influence width is removed from the inner surface profile by setting a range exceeding the variation allowance width as a shape influence width.

[0007]

The method for measuring the bead cutting shape on the inner surface of the ERW pipe according to the present invention is characterized in that ultrasonic waves are vertically incident from the outer peripheral side of the ERW pipe to be measured, and the inner portion of the ERW pipe including the welded portion when scanning in the pipe circumferential direction is included. After detecting the outer surface reflection echo positions, profile processing of the inner and outer surfaces is performed from these detected positions, an average value of the outer surface profile in the base material portion is obtained, and a vertical allowable fluctuation width is provided for the average value, Since the shape influence width is removed from the inner surface profile by setting the range exceeding the allowable width as the shape influence width, an inner surface profile free from external cutting effects can be obtained.

[0008]

BRIEF DESCRIPTION based on examples illustrating the method of measuring electrostatic sewing tube surface bead cutting shape of the present invention in FIGS. 1-7. 1 (a) is explanatory view of the vertical reflection of the ultrasonic wave used in the present invention method, (b) is an explanatory view of the reflected echoes, 2
FIGS. 3A and 3B are diagrams illustrating signal processing according to the method of the present invention, in which FIG. 3A is a drawing near a welded portion of an ERW pipe, FIG.
(C) is a drawing showing an inner surface profile before signal processing,
(D) Drawing and figure showing the inner surface profile after signal processing
3 is a flowchart of the method of the present invention, FIG. 4 is a block diagram of an apparatus for performing the method of the present invention, and FIG. 5 is a diagram showing a measurement result of an inner surface profile when the method of the present invention is performed.
(A) is a drawing near the welded portion of the ERW pipe, (b) is a drawing showing the inner / outer surface profile, (c) is a drawing showing the inner surface profile after signal processing, and FIG. 6 is an apparatus for implementing the method of the present invention. front view of an example, FIG. 7 is an enlarged view of the contact roller portion of FIG.

[0009] The measurement principle of the present invention method is obtained by utilizing the vertical reflection of ultrasonic waves. That is, FIGS. 1 (a)
When ultrasonic waves are vertically incident on the ERW tube 1 from the ultrasonic probe 2 in water as shown in FIG. 1 , the reflected waves S and B are reflected from the outer surface and the inner surface as shown in FIG. can get. At this time, the time from the transmission wave T to the external reflection wave S is t ₁ , and the time from the transmission wave T to the internal reflection wave B is t ₂ . The outer surface profile is determined by t ₁ × underwater sound velocity, and the inner surface profile is t ₁ ×
Determined from the sum of the underwater sound velocity and (t ₂ −t ₁ ) × the sound velocity in steel.

[0010] The weld portion 1a of the electric-resistance-welded pipe 1, when scanned with a follow-up mechanism having a contact roller 3 as shown in FIG. 7, the base material A of electric-resistance-welded pipe 1 and E and the outer cutting center In the portion C, a stable inner and outer surface profile is obtained, but in the outer edge portions B and D of the electric resistance welded tube 1, the outer surface profile has a shorter water distance (the distance from the ultrasonic probe 2 to the outer surface). since FIG. 2 (b) is chevron-shaped as shown in occurs, also the inner surface profile complexly catadioptric ultrasonic FIG
As shown in (c), a result matching the inner surface shape cannot be obtained.

Therefore, the present inventor has paid attention to the fact that the inner surface profile is not stable when the outer surface profile has a chevron shape, and has established the following method of the present invention.

That is , in the method of the present invention, as shown in the flow chart of FIG. 3 , first, ultrasonic waves are vertically incident from the outer peripheral side of the ERW pipe 1 to be measured and the welded portion 1a is included in the pipe circumferential direction. Processing is performed to obtain an outer surface profile from the echo position of the outer surface reflected wave S during scanning, and an average value of the base material portion is obtained. Then, a variation allowable value is set above and below the average value to set a variation allowable width [FIG. 2 (b)].

Next, a range in which the outer surface profile exceeds the fluctuation allowable width is set to c, and the enlarged width d is added to the c to obtain a shape influence width L. Then, an inner surface profile is obtained in the same manner as the outer surface profile [FIG. 2 (c)], and both ends of the shape influence width L are connected by straight lines in the inner surface profile, as shown in FIG. 2 (d). An unaffected inner profile will be obtained. In this embodiment, the inner surface profile may be determined by the value of t × the speed of sound in steel.

[0014] In order to confirm the effect of the present invention method, Fig. 7
A device equipped with a follow-up mechanism having a contact roller 3 as shown in Fig. 1 was installed immediately after cutting the welded part of the ERW pipe manufacturing line, and measurement was performed by a partial water immersion method using a high-frequency, point-focus type probe. Was.

[0015] shows a block diagram of the present invention a method implementing the device configuration in FIG. 4, the scanning of the ultrasound probe 2 is performed at run査制control circuit 4, the signal of the ultrasonic probe 2 flaw detector 5 And the time from the transmission wave T to the external reflection wave S is t ₁
The time until the inner surface reflected wave B is measured t _2, the profile processing of inner and outer surfaces is performed with. After the profile processing is performed, the result is output to the arithmetic unit 6, and the arithmetic unit 6 performs the two composite processing calculations and performs the monitor 7 processing.
Displays the processed inner profile.

Using the apparatus described above, the outer diameter is 508 m.
FIG. 5 shows the results of measuring the inner and outer surface profiles of the undercut portion 1b (see FIG. 5 (a)) of the inner surface of the welded portion 1a of the ERW pipe 1 having a thickness of 8.74 mm. FIG. 5 (b)
The inner and outer surfaces profile pretreatment, (c) is showing the inner surface profile after treatment with the method of the present invention, it was confirmed that the outer cutting receiving no inner surface profile of the edge effects can be obtained according to the method of the present invention .

[0017]

As described above, according to the method for measuring the inner bead cut shape of the ERW pipe of the present invention, the inner cut shape of the welded portion of the ERW pipe can be measured without being affected by the outer shape. As a result, it is possible to improve the quality and yield during the production of the ERW pipe.

[Brief description of the drawings]

FIG. 1A is an explanatory diagram of a vertical reflection of an ultrasonic wave used in the method of the present invention, and FIG. 1B is an explanatory diagram of a reflected echo thereof.

FIGS. 2A and 2B are diagrams for explaining signal processing of the method of the present invention, wherein FIG. 2A is a drawing near a welded portion of an ERW pipe, FIG. 2B is a drawing showing an outer surface profile, and FIG. 2C is a drawing showing an inner surface profile before signal processing. The drawing (d) shows the inner surface profile after signal processing.

FIG. 3 is a flowchart of the method of the present invention.

FIG. 4 is a block diagram of an apparatus for implementing the method of the present invention.

5A and 5B are diagrams showing measurement results of an inner surface profile when the method of the present invention is carried out, wherein FIG. 5A is a drawing near a welded portion of an ERW pipe, FIG. 5B is a drawing showing an inner and outer surface profile, and FIG.
3 is a drawing showing an inner surface profile after signal processing.

FIG. 6 is a front view showing an example of an apparatus for performing the method of the present invention.

FIG. 7 is an enlarged explanatory view of a contact roller section of FIG. 6 ;

8A and 8B are explanatory diagrams of a method of measuring an inner surface profile using a conventional ultrasonic thickness gauge, wherein FIG. 8A is an explanatory diagram of a vertical reflection of an ultrasonic wave, FIG. 8B is an explanatory diagram of a reflected echo thereof, and FIG. It is a drawing showing a profile.

[Explanation of symbols]

 1 ERW pipe 1a Welded area L Shape influence width

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshio Udagawa 2-10-12 Dogenzaka, Shibuya-ku, Tokyo Inside Clout Kramer Co., Ltd. (56) References JP 2-12005 (JP, A) JP JP-A-56-606 (JP, A) JP-A-59-97003 (JP, A) JP-A-6-317418 (JP, A) JP-A-56-35057 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) G01B 17/00-17/08 G01N 29/00-29/28

Claims (1)

(57) [Claims] 1. A method of measuring the inner cut shape of an ERW pipe using an ultrasonic wave after welding a butt portion along the pipe axis direction and cutting an outer weld portion thereof with a bead cutter or the like. After ultrasonic waves are vertically incident from the outer peripheral side of the electric resistance welded pipe to detect the inner and outer surface reflected echo positions at the time of scanning in the pipe circumferential direction including the welded portion, the inner and outer surface profile processing is performed from these detected positions. The average value of the outer surface profile in the base material portion is obtained, a vertical allowable variation width is provided for the average value, and a range exceeding the allowable variation width is set as a shape influence width, and the shape influence width is removed from the inner surface profile. A method for measuring a bead cutting shape on an inner surface of an electric resistance welded pipe, characterized in that: