JPS6025234B2 - Method for measuring metal flow angle of welded part of ERW welded pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring in real time the metal flow angle of a weld immediately after welding during the manufacture of an electric resistance welded pipe.

In electric resistance welded pipes, the metal flow angle a' at the welded part is defined as the following formula from the cross section of the electric resistance welded pipe in Figure 1, and H4) It is known to be an indicator of weld strength.

Therefore, in the manufacture of ERW welded pipes, if the metal flow angle of the welded part can be measured in real time immediately after welding, and the welding conditions can be managed and controlled based on the measurement results, the occurrence of defective products can be greatly reduced. It is clear that it is possible to suppress the amount of waste and perform extremely lean operations.

However, in conventional box-stitched pipe manufacturing, the metal flow angle of the weld can only be measured from the manufactured, i.e., bead-cut, cut-to-length pipe; It has been impossible to measure the metal flow angle of the weld in real time.

Therefore, the present inventors conducted research to solve the above-mentioned problems, and as a result, they obtained the following knowledge.

That is, (1) By applying the optical cutting method, it is possible to detect an optical cutting profile corresponding to the cross-sectional shape of the welded part immediately after welding before bead cutting. On the other hand, as shown in Fig. 2, which shows an example of the cross-sectional shape of a welded part, the angle between the base of the weld bead 1 and the reference (horizontal) line is 8L, based on the two rising positions la and lb of the weld bead. 8R
It was found that there is an extremely close correlation between (a=season (OL+OR)) and the metal flow angle in the welded portion, as shown in FIG.

(2) Therefore, based on the optical cutting profile detection information of the welded part immediately after welding obtained by the optical cutting method, the metal flow angle of the welded part immediately after welding can be determined in real time with extremely high accuracy. This invention has been made based on the above findings, and includes irradiating a slit light onto a welded part of a moving Qin pipe before bead cutting, and transmitting the light cutting profile obtained at the welded part to an optical image receiving means. and from the optical cutting profile image reception signal obtained by the optical image receiving means, the maximum height of the bead in the welded portion is within the range of 3/4 to 1/3 of the maximum height of the bead with reference to the rising position of the bead of the welding part. The surface position of the bead corresponding to a predetermined height is detected, and the welding is performed based on the horizontal distance from the rising position at the surface position of the bead corresponding to the predetermined height obtained in this way and the predetermined height. The present invention is characterized in that it is a method for measuring a metal flow angle at a welded part of a welded welded pipe in which the metal flow angle at the welded part is calculated.

The present invention will be explained below by way of examples with reference to the drawings.

FIG. 4 is an explanatory view showing one embodiment of a weld metal flow angle measuring device for an electric resistance welded steel pipe for carrying out the present invention.

As shown in the figure, a blank pipe 2 obtained by forming a plate material into a tubular shape and welding the abutting portions with a locking stitch moves in the direction of arrow a, and the bead 1 on the top thereof maintains a predetermined temperature. While he is doing so, his portrait is destroyed by a cutlet (not shown).
A cylindrical lens 3 is provided directly above the Qin pipe 2 at the bead 1 and the surrounding area (welded part) of the raw pipe 2 immediately after welding.
A slit light 4 of a single wavelength is irradiated from. 5 is a laser light generator, from which He-Cd laser light with a wavelength of, for example, 4416A is supplied to the cylindrical lens 3 through an optical fiber 6, and becomes a slit light 4, which is e.g. The welded portion of the millet pipe 2 is irradiated obliquely at an angle of 10 to 40° C. and along the circumference of the pipe.

In this way, the light cutting profile 7 (reflected light from) corresponding to the cross-sectional shape of the welded part caused by the irradiation of the single-wavelength slit light 4 at the welded part of the Aoi pipe 2 is The light passes through a narrowband interference filter 8 whose center band is the wavelength of the light 4, and is received by an ITV camera 9. The optical cutting profile image reception signal from the ITV camera 9 is sent to the frame memory 1O', where image data corresponding to the profile is recorded. An example of the received image of the light cutting profile 7 in the frame memory 10 is shown in FIG. 5A. Then, from the sampling line selection signal generation circuit 11, N(
The vertical scanning signal for scanning (number) is stored in the frame memory 1O.
'This is input to the maximum brightness detection circuit 12 for each vertical scanning signal.
The image coordinates X in the frame memory 10' are
The maximum brightness of each coordinate of the axis (on the Y-axis coordinate), that is, the received image of the light cutting profile 7 is detected. For example, in Fig. 5A, Y
The phantom coordinates on the axis are detected as the coordinates on the Y axis that give the maximum brightness (see Figure 5). In this way, the Y-axis upper coordinate giving the maximum brightness of the image coordinates in the frame memory 1 is stored in the one-dimensional memory 13 with a capacity equal to the number N of vertical scanning signals, and then the shape index calculation circuit 14 stores it in the one-dimensional memory 13. The difference between the 13 adjacent stored data is calculated based on the following formula. △=yi+, yi (1mii<N-1)
In this way, even though it is image processing, it is essentially one-dimensional data processing, so it is possible to calculate the metal flow angle in real time (
measurement).

Based on the data thus obtained, the shape index calculation circuit 14 calculates the coordinates (x
L, yL) and (xR, yR) (see Fig. 5A) are calculated based on the following formula. △yL＞△y＊△yl＜△y＊
(1SISL-1) △yR-, Kuichi △y* △ym>-△y* (Rmi m<N-1) (However, △y* is an appropriate constant) In addition, in the shape index calculation circuit 14 , from the data stored in the primary nine memory 13, the coordinates (xT, yT) that give the maximum coordinates on the Y axis are found, and as shown in FIG. The bead heights HL and HR (Fig. 7) corresponding to the coordinates of the predetermined height within the range of ~1/3, y′T) and (x″,,y″T) are as follows: Desired.

That is, as shown in FIG. 6, the angle of the incident light 4 to the bead with respect to the tangent passing through the outer surface of the tube at the bead level?
, and when the reflected light 4' to the ITV camera 9 is in a positional relationship forming an angle 2, the bead portion of the height HL2 is represented by a line segment AB as shown in FIG. The incident light from the light source passing through this is the line segment DC, EB, and its ITV
When the reflected light to the camera is represented by line segments AF and CG, since the bead is small, the line segments DC and EB and AF and CG can be considered to be parallel, respectively. Then, <DCPni<E
BP: of. ...■, so
<DCG Junior High School 1 (No, 2 of 10). ．． ．． ■
becomes.

At this time, if the length of line segment FG is hL, hL=IAC
lsin neck ℃ Ni IAClsin {Tenichi (of, tenth two)
)} NiIAClsin(of, 2 of 10) ...■, so IACI=hL/sin(of, 2 of 10)
…becomes @.

In addition, the length HL of the line segment AB is calculated from the formula (■) by HLdIABI
2.IAClsin. ... becomes ■. Therefore, by substituting the formula (■) into the formula (■),
in(of, 2 of 10)=K(y′T−yL)sin. /
sin (no. 10 2)
．． ．． ．． (2) However, K is a coefficient for converting the coordinate height y'T-yL of the image in the frame memory into the actual size hL.

becomes. Here, , , and 2 are constants determined by the light source and the installation position of the ITV camera, so in equation (■), k
If we set sin's, /sin ('s, 2 of 10) = k', ■
The formula is further expressed as HL=k'(y'T-yL)
...■■It can also be multiplied like the expression.

Similarly, for the other height HR, HR=k(y″T−yR)sin,/sin(of,
2 of 10) ...■Or, HR=k'(y''T-yR) ...■.

In addition, the shape index calculation circuit 14 calculates the coordinates (
x′,,y′,) and (x″,,y″T),
The rising position of the bead (xL, yL) and (xR, yR
) are determined by BL niz T1 x L and BR=xR1 x'' (see Fig. 7).

Thus obtained HL and BL, HR and BR', aL sail, elbow side of the vessel, drum-shaped female number chest familiarization, and vertical touching to obtain OL and OR, and the result of this calculation is Based on the same circuit 14, metallization is performed.

One angle 8: Back (8L+aR) is calculated. In addition, H.L.
and when calculating HR, use this as 3/3 of (xT, y')
The reason why we decided to calculate it from the coordinates of a predetermined height within the range of 4 to 1/3 is that if the above range is excluded, the error between the actual metal flow angle and the calculation result will exceed the allowable limit. This is because 15 and 16 are analog outputs of the metal flow angle calculation results of the welded part immediately after welding, which are thus calculated by the shape index calculation circuit 14;
Terminal 17 for digital output is ITV camera 9
and C for monitoring the video in the frame memory 10.
It is RT.

As explained above, in this invention, the cross-sectional shape of the weld immediately after welding can be detected, and the metal flow angle of the weld can be determined in real time from the detection results of the height inside the bead. This can contribute to the production of hemlocked tubes.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the saddle canal, Figures 2 and 7.
The figure shows an example of the cross-sectional shape of a welded part of an electrically welded pipe, Fig. 3 shows an example of the relationship between the metal flow angle and the beat height and center, and Fig. 4 shows an example of the relationship between the metal flow angle and the beat height and inside. An explanatory diagram showing one aspect of a metal flow angle measuring device for a welded part of a lock-stitch welded pipe, Fig. 5 A is a diagram showing an example of a received image of a light cutting profile in a frame memory, and Fig. 5 A shows an example of a received image of a light cutting profile in a frame memory. A diagram showing an example of the detection mode by the detection circuit, FIG. 6 is a diagram showing an example of the relationship between the slit light, the ITV camera, and the tube, and FIG. 8 is an explanation for explaining how to obtain a predetermined beat height. It is a diagram. 1...bead, 2...substitute, 3...
...Cylindrical lens, 4...Slit light, 5...Shi-za light generator, 6...
Optical fiber, 7... Optical cutting profile, 8... Narrow band interference filter, 9... I
TV camera, 1 0...Frame memory, I1...
...Sampling line selection signal generation circuit, 12...
... Maximum brightness detection circuit, 13... One-dimensional memory,
14. ．． ．． ．． ．． ．． Decision index calculation circuit, 15, 16...
...Terminal, 17...CRT. Figure 2 Figure 3 Figure 5 Figure 6 Figure 8

Claims (1)

[Claims] 1. Irradiating the welded part of the moving blank pipe before bead cutting with slit light, receiving the light cutting profile obtained at the welded part by an optical image receiving means, and receiving the light obtained by the optical image receiving means. Detecting a surface position of the bead corresponding to a predetermined height within a range of 3/4 to 1/3 of the maximum height of the bead based on the rising position of the bead of the welding part from the cutting profile image reception signal. , The metal flow angle of the welding part is calculated based on the horizontal distance from the rising position at the surface position of the bead corresponding to the predetermined height obtained in this way and the predetermined height. Method for measuring metal flow angle at welded part of sewn welded pipe.