JPH05154510A - Method and instrument for detecting shape of welded part at butt-welding - Google Patents

Abstract

PURPOSE:To secure detecting accuracy and to improve welding quality by measuring cross sectional shape of the welded line along the welded line from the front and back surfaces of the welded part after a butt welding is executed and a welded bead is trimmed and detecting dislocated rate and remaining bead in the welded part. CONSTITUTION:After the facing end surfaces of the preceding steel strip 3 and the following steel strip 4 are butt-welded, the trimming is executed and the cross sectional shape at the welded part 5 after trimming is continuously measured from the front and back surfaces. Thereafter, these shape measured data are compared and calculated and the dislocated rate and the remaining bead of the preceding and the following steel strips are detected. Further, a shape measuring instruments 61, 62 arranged facing to the upper surface and the lower surface of the welded part just behind a bite of a trimmer in a steel strip welder and measuring the vertical cross sectional shape to the welded line in the welded part along the welded line, are provided. An information treating device 13 for detecting the dislocating rate and remaining bead in the preceding and the following steel strips by comparing and calculating the shape measured result and the thick informations of both steel strips, is arranged. By this method, the welded quality is secured and the welded breakage is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the shape of a welded portion during butt welding and an apparatus therefor, and more specifically, prior to continuously passing a steel strip through a cold rolling mill or the like, the preceding material is used. The present invention relates to a method and an apparatus for detecting the shape of a butt-welded portion when butt-welding a tail end of a sheet and a tip of a trailing member.

[0002]

2. Description of the Related Art Generally, prior to continuous processing in a cold rolling line or a pickling line, the opposite ends of the steel strips of the preceding material and the following material are butt-welded to make the steel strip continuous. The subsequent process is continuously threaded. In order to prevent the welded portion from breaking in the subsequent process, that is, in the pickling line and the cold rolling line, it is necessary to maintain the same shape condition as that of the base metal. Therefore, with respect to the shape of the butt welded portion, the pass / fail judgment is generally performed by inspecting the presence or absence of a step (bead remaining) after trimming the bead of the welded portion and the size thereof. As one of the step inspection means, it has been proposed to attach a shape detector to the trimmer and detect the shape of the weld portion immediately after trimming the weld bead (Steelmaking Research No. 307, page 35). ..

That is, in this shape detecting device, a contact pressed against the surface of a weld to be measured is slid along a welding line, and the amount of vertical movement of the contact during this sliding is detected by a differential transformer. Then, it is an apparatus for amplifying, recording and detecting this as desired. When the shape detectors are continuously arranged in the transverse direction of the weld at a predetermined pitch, the cross-sectional shape of the weld can be continuously inspected at the same time as trimming, but there are the following problems. (1) Since this shape detector has a mechanical and complicated structure, it has a short life and is difficult to maintain. (2) The measurement accuracy is low because it is detected by the amount of vertical movement of the contact that contacts the weld. That is, there are severe irregularities on the boundary surface between the trimming portion and the surface of the mother board, and as a result of riding on spatter or cutting powder, it is affected by this.
It is difficult to obtain the predetermined measurement accuracy. (3) Since the measurement pitch is large (3 mm), it is impossible to capture a detailed cross-sectional shape for knowing the deformation state of the plate before and after the trimming part.

Further, as a widely used method, there is a method of obtaining a cross-sectional shape by synthesizing shape measurement data on only one surface and plate thickness data separately measured at an upstream value. In that case, if it is desired to obtain the cross-sectional shape over the entire width, the plate thickness data also needs to be detailed, and if such detailed plate thickness data is to be quickly collected in the plate. Requires extensive measuring equipment.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems. Specifically, the distance to the surface of the welded portion is determined by using an optical range finder without contacting the welded portion. It is an object of the present invention to provide a welding part shape detecting method and apparatus for detecting the shape from this distance.

[0006]

First, in order to solve the above-mentioned problems, the present invention provides a pair of upper and lower parts for measuring the distance from the surface of the welded part by bringing them close to the cutting tool of the trimmer for trimming the weld bead. The distance measuring device is provided, and the distance to the surface of the weld is measured at a fine pitch in the cross-sectional direction of the weld without contacting the surface of the weld.

Next, the information processing unit processes the two-dimensional distance data obtained by the pair of upper and lower distance measuring devices to display each cross-sectional shape as an image and to measure the distance at a fixed position before and after the trimming portion. The data is compared and calculated, and the level difference between the preceding and following steel strips in the amount of misalignment of the abutting surfaces is detected.

Next, the distance data at the fixed points before and after the trimming portion are compared with all the distance data up to the trimming center, and the amount of remaining beads (the surface of the mother board and the trimming bite surface) is determined by the deviation thereof. Step) is detected.

[0009]

1 is an explanatory view showing the principle of the shape detecting device according to the present invention, FIG. 2 is a front view of the shape detecting device according to one embodiment of the present invention, and FIG. 2 ZZ
4 is a side view from the direction, FIG. 4 is an explanatory view of a shape factor detected in the present invention, FIG. 5 is an explanatory view of a measurement principle of misalignment of the welded portion, and FIG. 6 is a bead of the welded portion. FIG. 4 is an explanatory diagram of the remaining measurement principle.

First, in FIG. 1, reference numerals 1 and 2 respectively indicate an outgoing side electrode, an incoming side electrode, 3 indicates a leading material, 4 indicates a trailing material, and the opposing ends of the leading material 3 and the trailing material 4 are butted. It is welded and the welded part 5 is formed there. A pair of distance measuring devices 61, 62 vertically sandwiching the weld 5
For example, two-dimensional laser rangefinders 61 and 62 are provided. These rangefinders 61, 62 are provided in close proximity to the trimmer bite, as shown in FIGS. That is, the steel strip is butt-welded between the fixed base 7 and the movable base 8 by the inlet side and outlet side electrodes 1 and 2, and the welding beads thereof are the upper and lower trimming bits 91, 1.
It is cut by 01 and trimmed. Each byte 9
1 and 101 are held by the bite holders 11 and 12 of the upper carriage 9 and the lower carriage 10 of the trimmer, respectively (see FIG. 3). Distance meters 61 and 62 are provided immediately after the bite holders 11 and 12, respectively. By doing so, the welded portion after the butting can be trimmed, and immediately after that, the distance to the surface of the welded portion can be continuously measured along the welding line.

Further, the distance information from each of the distance meters 61 and 62 is sent to the information processing device 13, and based on the processing in this device 13, the display device 14 has a cross-sectional profile of the welded portion and a difference in level. , The rest of the bead, etc. are displayed. Further, in the information processing device 13, the previously input pass / fail judgment reference value is compared with the measurement data, and if the welding shape is defective, for example, there is a misalignment (level difference), an alarm is issued.

That is, according to the present invention, the distances 61 and 62 provided behind the cutting tools 91 and 101 of the trimmer measure the distance to the surface in the direction perpendicular to the welding line, that is, in the cross section of the welding portion. For example, it is possible to measure at intervals of 0.2 mm and display an image as a cross-sectional shape on the display device 14. On the other hand, since the measurement cycle can be made constant, for example, 60 times / second, each welding cross-sectional shape for each measurement cycle can be captured along the welding line during trimming. Therefore, in the above measurement distance, before and after the trimming part,
By comparing the data at a certain position, it is possible to detect the amount of misalignment (difference in level of the steel strip abutting surfaces). Further, by comparing the data at the above-mentioned fixed position with the data up to the trimming center, the bead remaining (trimming remaining) can be detected. More specifically, in FIG. 4, the leading material 3 and the trailing material 4 are butt-welded and the welded portion 5 is shown. In the welded portion 5, the dotted line portion of the bead is trimmed as the trimming portion 51, and the surfaces of the preceding and following mother boards are left as 31 and 41 adjacent to both sides of the trimming portion 51. Therefore, on the removal surface 52 of the trimming portion 51, the profile is displayed on the display device 14 as described above, and the removal surface 52 and the mother board surfaces 31 and 41 have the same cross-sectional shape, and the image is displayed on the display device 14. In addition to being displayed, when these distance data are compared, as shown in FIGS. 5 and 6, the misalignment amount (e) and the bead remaining amount (B) can be easily obtained.

First, the misregistration amount (e) is detected according to the principle shown in FIG. When the plate thicknesses of the preceding and following preceding material 3 and the following material 4 are known, each plate thickness is t
Let ₁ and t ₂ . At this time, if the distances 61 or 62 determine the measured distances at the fixed points before and after the trimming portion 51 as a, b, c, and d, the misalignment amount (e) is represented by the number 1 or the number 2 on the attached sheet. ..

[0014]

[Equation 1]

[0015]

[Equation 2]

Therefore, the misregistration amount (e) can be detected by inputting the plate thicknesses t ₁ and t ₂ as coil information to the information processing device 13 in advance. If the plate thickness of the preceding material 3 or the following material 4 is unknown, the upper and lower distance meters 61,
When the measurement distances a and b on the upper surface of the welded portion and those c and d on the lower surface are measured by 62, the misalignment amount (e) can be detected by the number 3 on the separate sheet.

[0017]

[Equation 3]

The remaining bead (B) is detected according to the principle shown in FIG. The cross section of the welded portion 5 is centered on the trimming portion 51, and is located at the front, rear, upper and lower zones Z ₁ , Z ₂ ,
Divided into Z _3, Z _4, each zone - down _{Z 1, Z 2, Z 3} , and all the distance values measured by the upper and lower range finder 61 and 62 for Z _4, each zone - Distance in emissions a~d From the deviation from
The remaining amount (B) ', that is, the step difference between the trimming bite surface and the mother plate surface is detected.

Further, when the misalignment amount and the bead remaining amount are obtained for each cross section of the welded portion in this way, these acceptance criteria are preliminarily input to the information processing apparatus 13, so that each pass / fail determination is made. It is compared with the reference, and in the case of a defective shape, an alarm is issued and welding is performed again or cutting is performed again.

The shape measuring device can be constructed from any device as long as it can measure the distance, but can be constructed as a laser range finder as shown in FIG. That is, in FIG. 7, reference numerals 3 and 4 are leading materials, trailing materials and 5 are welded portions, for example, a semiconductor laser 20 and a collimator 21.
Then, the laser light is applied to the welded portion 5. The reflected light is received by the image sensor 23 via the lens 22, and the distance can be measured as a two-dimensional one.

[0021]

As described in detail above, the present invention is a method and apparatus for detecting the shape of a welded portion during butt welding of steel strips, in which the opposing end faces of the leading and trailing steel strips are welded after the butt welding. After trimming the cable, measure the cross-sectional shape perpendicular to the weld line of the weld from the front and back sides in the vicinity of the weld after the trimming, continuously along the weld line, and compare the shape measurement data. Then, the misalignment amount of the leading and trailing steel strips and the bead remaining in the welded portion are detected. Further, in detecting the shape of such a butt-welded portion, it is arranged to face the upper surface and the lower surface of the welded portion just after the bite of the trimmer of the welding machine that butt-welds the opposite end surfaces of the leading and trailing steel strips. , A shape measuring device that continuously measures the cross-sectional shape perpendicular to the welding line of the welded part along the welding line, and the calculated result and the thickness information of both steel strips are compared and calculated to calculate the amount of misalignment and And an information processing device for detecting the rest.

Therefore, according to the present invention, there is a strong tendency that the open end of the plate is not straight in the wide and thin butt joint because it is possible to guarantee the inspection accuracy which is difficult to achieve by the conventional technique. That is, the misalignment amount and the misalignment direction are likely to change. In this method, since the plate surface and the bead surface are directly measured from both sides, detailed shape changes can be accurately traced in this case as well. In addition, by automating the shape inspection of the welded part, it can contribute to the prevention of weld fracture in the cold rolling and the continuous annealing process of the next process by guaranteeing the welding quality, and by the speedup of welding inspection and re-welding, cold welding can be performed. Rolling downtime can be reduced. Also,
Since the inspection work can be omitted, the load on the operator is reduced. Furthermore, the quantitative welding shape data enables efficient establishment of welding conditions and facility management.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the principle of a shape detection device according to the present invention.

FIG. 2 is a front view of a shape detection device according to one embodiment of the present invention.

FIG. 3 is a side view from the ZZ direction of FIG.

FIG. 4 is an explanatory diagram of form factors detected in the present invention.

FIG. 5 is an explanatory diagram of a principle of measuring a misalignment of a welding bead.

FIG. 6 is an explanatory diagram of a bead remaining measurement principle of a welding bead.

FIG. 7 is a perspective view of a laser range finder as an example of a shape measuring device.

[Explanation of symbols]

 3 Leading material 4 Trailing material 5 Welded portion 13 Information processing device 14 Display device 61 Shape measuring device 62 Shape measuring device

Claims (3)

[Claims] 1. A cross section perpendicular to the weld line of the welded portion after the butt-welding welded beads are trimmed after the butt-welding and then the welded portion is trimmed in the vicinity of the welded portion after the trimming. The shape is continuously measured along the welding line, and the shape measurement data is compared and calculated to detect the misalignment amount of the leading and trailing steel strips and the bead residual in the welded portion. Method for detecting weld shape during butt welding. 2. In a steel strip welding machine for butt-welding opposite end surfaces of leading and trailing steel strips and trimming a bead of the welded portion, an upper surface and a lower surface of the welded portion immediately after a cutting tool of the trimming trimmer. Placed opposite to
A shape measuring device for continuously measuring a cross-sectional shape perpendicular to the welding line of the welded portion along with the welding line, and the preceding and following operations by comparing and calculating the shape measurement result and the thickness information of both steel strips. An apparatus for detecting the shape of a welded portion at the time of butt welding, which is provided with an information processing apparatus for detecting the amount of misalignment of steel strips. 3. The welded portion shape detecting device during butt welding according to claim 2, wherein the shape detecting device is a laser range finder.