JPS61172006A - Welded step meter of pipe seam part - Google Patents

Abstract

PURPOSE:To effect accurate measurement of welded step by measuring a distance up to the both ends of the welded portion on the same periphery, detecting horizontally displacement intersecting the specimen pipe axis perpendicularly and correcting the difference of detected distance values. CONSTITUTION:A pipe P is conveyed with its welded portion B facing upward along the pipe axis CL on a conveying table. Distance detectors D1, D2 are arranged on both sides of the CL at an equal distance l1 above the pipe P and measure distances L1, L2 up to points S1, S2 on the periphery on both sides of the welded portion B of the pipe P respectively. Distance detectors D3, D4 are arranged on both sides of the pipe P and at an equal distance l2 on both sides of the conveying center line CL and detect distances L3, L4 up to the outer periphery of the pipe P. A half of the difference of the detected distances L3, L4 represents horizontal displacement relative to the conveying center line CL of the pipe P. During the course of travel of the pipe if a displacement occurs horizontally from the center line, accurate measurement of a welding step becomes possible, by correcting the difference of the detected distances corresponding to the detected displacement.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for measuring the level difference in a welded part of a welded pipe.

[Conventional technology]

The welded part level difference of a welded pipe, that is, the welded part level difference caused by the misalignment K of the butt parts of the material side ends before welding, has a large relationship with the quality of the welded part of the pipe, and is an important control item in the welded pipe manufacturing process. There is one.

As a conventional method for measuring this welded part level difference during manufacture of a welded pipe, there is a method described in Japanese Patent Application Laid-Open No. 137801/1983. This method uses the optical cutting profile received signal obtained by irradiating the welded part of the pipe with slit light to determine the X-Y Find the coordinates and calculate the X-Y of each point
From the coordinates, calculate the equation of the circle on the outer peripheral surface on both sides of the weld (y = g
t, (x).

Find y = gm(d) and calculate the difference between the two (D = IgL(
x) g, (x) I) is a method to find the welding part level difference.

(Problem A to be Solved by the Invention) It is of course possible to measure the weld level difference using the conventional method described above, but this method requires a complicated and expensive device configuration including an optical system and a signal processing device. Also, with this method, it is not possible to measure the level difference after cutting the weld bead, so the optical system is installed in a narrow space between the squeeze roll and the bead cutting machine, between immediately after welding and cutting the bead. There is the difficulty of having to install it.

Therefore, in order to measure the level difference in a welded part using a relatively simple device, the present invention aims to measure the level difference between both plate surfaces, which is conventionally used to detect the level difference during butt welding of flat plates such as steel plates. We decided to apply the method of calculating the step from the difference in distance,
The present invention aims to provide a method for correcting the step measurement error caused by the lateral deflection of the pipe, which is the object to be measured, by using this method and measuring the correct weld step.

(Ninth means for solving the problem) In other words, the present invention places a distance detector pointing near the weld boundary on the outer surface of the tube in the tube transfer path, and This is a method of simultaneously detecting the distances to the vicinity of the boundaries on both sides of the weld on the circumference, and determining the step of the weld from the difference between the two distance detection values. When the pipe is displaced in the horizontal direction, this displacement changes the distance detection value and causes an error in the step measurement value.In order to correct this error, the amount of horizontal displacement of the pipe is detected, and this displacement amount detection value is This is a method for measuring a step difference in a welded part of a welded pipe, in which the difference in the detected distance value is corrected according to the detected distance value.

(Example and operation) The present invention will be described in detail below based on an example in which the present invention is applied to measurement of a welded part level difference in a manufacturing process of an electric resistance welded steel pipe.

FIG. 1 is a front view showing the arrangement relationship between an object to be measured and a detector in an embodiment of the present invention.
are the distance detectors placed above the pipe P % I) s and D
4 is a distance detector placed on both sides of the pipe P, respectively. The pipe P is placed on a transfer table (not shown) and is being transferred in the pipe axial direction with the center of the transfer center line CLt - the welded part B directly above. Distance detectors DI and Dl are placed above the pipe P and on both sides of the conveyance center line CL at an equal distance t1, and are located at points S1 and S on the outer circumferential surface on both sides of the welded part B of the pipe P to the snow. Distances Ll and Let are respectively detected. Distance detectors Ds and D4 are located on the sides of the pipe P and at the transport center line CL.
equidistant on both sides of t! The distances L3 and L4 to the outer peripheral surface of the pipe P are detected. This distance detection value L3
The difference V2 between and L4 becomes the amount of horizontal displacement of the pipe P with respect to the transfer center line CL.

FIG. 2 is a rounded diagram illustrating the weld level difference and the principle of its measurement. For convenience, in this figure, the tubular shaped raw pipe p before welding is shown in place of the pipe P in Figure 1, and the butting portions of this raw pipe p are shown at different positions (the figure is exaggerated). This is the weld step after welding. Therefore, the weld step is originally the difference shown by W in the figure, but since it is not possible to measure the amount of W online after welding, it is In operation, the difference in height between points (sl and S30 points in this example) that are a certain distance away from the abutting portion is used as a management step. The difference in height between the point S1 and the point S is obtained by determining the difference between the distances L1 and L3 from the reference position above the tube to the point. That is, in this embodiment, the welding part step difference Δh is Δh=Ll-1. Snow ・・・・・・・・・It is obtained as (1).

However, in the actual manufacturing process, there is no guarantee that the center of the pipe P passes through the transfer center line CL;
The center of the pipe P actually being transferred is often displaced in the horizontal direction with respect to the predetermined transfer center line CL due to left-right vibration or lateral movement of the tube. If there is a horizontal displacement of the center of the tube,
An error occurs when the step difference is determined by the method explained in FIG. To explain this with reference to Fig. 3, as shown in Fig. 3, on the X-Y coordinate axis, the center of the pipe P is the transfer center +
The origin is the coordinates of the tube center P0 when h coincides with @CL, and the center P of the tube P being transferred. If l is displaced by ΔI in the X-axis direction with respect to the transfer center line CLK, then the tube center P. The coordinates of l are (ΔX #O), and the formula representing the outer circumference of the pipe at this time is, assuming that the pipe P is circular, (X - Δx) +y ==R... Curve... (2) Ratio R can be expressed as the outer radius of the tube, and the position of any point on the tube outer circumference in the Y-axis direction can be expressed as.

From the above equation (3), points S1 and S on the outer circumference of the pipe in Fig. 3
! The position in the Y-axis direction, that is, the position in the height direction y8. and 7
112 is・ yll, = A animal T mouth; bottom ・・・・・・・・・(4) as2 ”” r stone −+ −7,) 2 ・・・・・・・・・
...It can be expressed as (5).

Therefore, if the center of the pipe P is displaced from the transfer center line by ΔI in the horizontal direction, the level difference calculated by the above equation (1) is
The apparent difference due to the displacement of the center of is the upper step (Δh1”ylll
Including 7fi2 will cause an error in the measured value. Therefore, in the present invention, this error is removed and summed to obtain the correct level difference, and the correct level difference Δh0 is calculated by the following formula 2 (%) = (L, -L2) - (A ring pebble doper) door〕···
・・・・・・(6) It is required.

When measuring the distance, move the distance detector vertically or vertically depending on the range of change in the outer diameter of the tube and the measurement accuracy of the distance detector itself.
(horizontally movable) or a combination of detectors with different measurement distance ranges (or measurement accuracy). As the distance detector, known distance detectors such as a length meter using a radar or microwave, an eddy current displacement meter, or a capacitance displacement meter can be used alone or in combination.

The installation location of the distance detector, that is, the step measurement location may be before or after cutting the weld bead.

(Effects of the Invention) As described above, according to the present invention, the welded part level difference of a welded pipe can be measured online in the welded pipe manufacturing process using a relatively simple device, and also during transportation. This has an excellent practical effect of being able to correct measurement errors caused by the horizontal displacement of the pipe and allowing accurate measurement of welded part steps.

[Brief explanation of the drawing]

Fig. 1 is a front view showing the arrangement of distance detectors in an embodiment of the present invention, Fig. 2 is a diagram for explaining the welded part step and its measurement principle in the present invention, and Fig. 3 is a diagram of the object to be measured. FIG. 6 is a diagram for explaining a measurement error of a welded part level difference based on horizontal displacement. P: Welded steel pipe B: Welded part p: Raw pipes D1 to D4: Distance detector. Figure 1 P: 31! r protection senei FS: · Kotobuki reading combination β D1-D4: distance Al1J moxibustion dekatsu 2nd figure p', s operation Dr-Dt: g huge M staff 11 figure 3 P: j8Mtgl tube D1-Dx: W big ^, 11 sandwiched heat 5 Procedural amendment θ year in Showa? Date of the incident: Showa ≦ O Patent Application No. 13173 & Person making the amendment (Relationship with the subject matter) Address: 2-6-3 Otemachi, Chiyoda-ku, Tokyo Name ( Name) (665) Nippon Steel Corporation ζ Agent Address 330 Marunouchi Building, 2-6-2 Marunouchi, Chiyoda-ku, Tokyo Amendment The following matters have been amended in the specification of the present application and in the interim. Note 1: The claims are amended as shown in the attached sheet. 2. On page 3, lines 10-11, the phrase "a distance detector directed near the boundary of the weld" is corrected to "two distance detectors directed near the border on both sides of the weld." 1, page 3, line 12, the phrase "on the same circumference of the tube" is corrected to "on the outer circumference of the tube." 4. On the 15th line of page 4, the phrase ``leave an equal distance ll on both sides'' is replaced with ``leave an appropriate distance 11 and 2 on both sides (1.=J12 in this example)
)” is corrected. 5. On page 4, line 18, "Display.Distance detector D2 As long as they are not extremely far apart in the longitudinal direction (for example, several hundred planes or more), there is no problem even if they are not on the same outer circumference in practice. Correct the distance detector D2 J. 6. On page 4, line 19, there is no problem. ``Place an equal distance 12 on both sides'' instead of ``Place an appropriate distance 13 and l+ on both sides (However, in this example, 13 = 1
4),” is corrected. 7. In the seventh negative line, "YB2"i77-ηF" is corrected to "rys2=v'77-;2ηF." 8. On the 2nd line of page 8, r = (Lx-L2) (Ding π for 6 animals>”-fFW Ding π
y)" is corrected to r = (Ll - L2) - (v'i dari stone) sword arf anusfu4 - 7)". 9. In the drawings, "Figure 1" to "Figure 3" are corrected as shown in the attached sheet. Claims: Two distance detectors arranged so as to point toward the vicinity of the boundaries on both sides of the weld on the outer surface of the object to be measured, respectively detect the distances to the vicinity of the boundaries on both sides of the weld on the outer periphery of the object to be measured,
In determining the welding part level difference from the difference in the direct distance detection values,
A method for measuring a step in a welded part of a welded pipe, comprising: detecting a displacement amount in a horizontal direction orthogonal to the tube axis direction of a measured object, and correcting a difference in the detected distance value according to the detected displacement value. Figure 1 p: 38Je Reiso E52, 5shi83if! iβ Dr-DA: Distance N0 Exit device 2nd diagram p: Subei Dr-Di: Distance A function 1* Instrument 3rd diagram Y P: j87 etgl operation D1 ~ Di-2 Giant ﾾsho JfL exit 5 -X

Claims (1)

[Claims] Distance detectors placed near the boundary of the weld on the outer surface of the object to be measured detect the distances to the boundaries on both sides of the weld on the same circumference, and determine the weld level from the difference between the two distance detection values. A welded part of a welded pipe, characterized in that in determining the distance, the amount of displacement of the object to be measured in a horizontal direction orthogonal to the tube axis direction is detected, and the difference in the detected distance value is corrected according to the detected displacement value. Step measurement method.