JP3064072B2 - Method and apparatus for detecting weld shape during butt welding - 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 and an apparatus for detecting the shape of a weld at the time of butt welding. More specifically, the present invention relates to a method for detecting a shape of a steel strip prior to continuously passing a steel strip through a cold rolling mill or the like. The present invention relates to a method and an apparatus for detecting the shape of a butt-welded portion when butt-welding the tail end of the butt-joint to the tip of a following material.

[0002]

2. Description of the Related Art Generally, prior to continuous processing in a cold rolling line, an pickling line, or the like, opposite ends of steel strips of a preceding material and a following material are butt-welded to make the steel strip continuous. Then, the subsequent process is continuously passed. In order to prevent the weld from being broken in the subsequent process, that is, the pickling line or the cold rolling line, it is necessary that the same shape condition as that of the base material be maintained. For this reason, regarding the shape of the butt welded portion, whether or not there is a step (remaining bead) after trimming the bead of the welded portion and the size thereof are generally determined to be acceptable or not. As one of the step inspection means, it has been proposed to attach a shape detecting device to a trimmer and to detect the shape of the weld immediately after trimming the weld bead (Iron Research No. 307, p. 35). .

That is, this shape detecting device slides a contact pressed against a surface of a weld to be measured along a welding line, and detects a vertical movement amount of the contact at the time of the sliding with a differential transformer. This is an apparatus for amplifying, recording, and detecting this as desired. If the shape detectors are continuously arranged at a predetermined pitch in the transverse direction of the welded portion, the sectional shape of the welded portion can be continuously inspected at the same time as trimming, but there is the following problem. (1) Since the shape detector has a mechanical and complicated structure, its life is short and maintenance is difficult. (2) Measurement accuracy is low because it is detected by the amount of vertical movement of the contact contacting the weld. In other words, the unevenness is severe at the boundary surface between the trimming portion and the base plate surface, and as a result of riding on spatter, cutting powder, and the like,
It is difficult to obtain a predetermined measurement accuracy. (3) Since the measurement pitch is large (3 mm), a detailed cross-sectional shape for knowing the deformation state of the plate before and after the trimming portion as a center cannot be grasped.

Further, as a conventional method, there is a method of obtaining a cross-sectional shape by synthesizing shape measurement data of only one side and thickness data separately measured at an upstream value. In this case, if it is desired to obtain the cross-sectional shape over the entire width, the thickness data also needs to be detailed in the same manner. Requires extensive measuring equipment.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems. Specifically, the present invention uses an optical distance meter without contacting a welded portion to measure the distance to the surface of the welded portion. It is an object of the present invention to provide a method and an apparatus for detecting a shape of a welded portion for detecting a shape from the distance and detecting the shape from the 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 a welded part by bringing the weld bead close to a trimmer cutting tool for trimming the weld bead. The distance to the surface of the welded portion is measured at a fine pitch in the cross-sectional direction of the welded portion without contacting the surface of the welded portion.

Next, the two-dimensional distance data obtained by the pair of upper and lower distance measuring devices is processed by an information processing unit to display each cross-sectional image as an image, and to display a distance at a predetermined position before and after a trimming portion. The data is subjected to a comparison operation to detect a difference in the amount of misalignment of the butted surfaces.

Next, the distance data at the fixed point before and after the trimming section is compared with all the distance data to the trimming center, and the deviation is used to determine the remaining amount of the bead (the base plate surface and the trimming bite surface). Is detected.

[0009]

FIG. 1 is an explanatory view showing the principle of a shape detecting apparatus according to the present invention, FIG. 2 is a front view of a shape detecting apparatus according to one embodiment of the present invention, and FIG. ZZ of 2
FIG. 4 is an explanatory view of a shape factor detected by the present invention, FIG. 5 is an explanatory view of a measurement principle of misalignment of a weld, and FIG. 6 is a view of a bead of a weld. FIG. 4 is an explanatory diagram of the remaining measurement principle.

First, in FIG. 1, reference numerals 1 and 2 denote an outgoing electrode and an incoming electrode, respectively, 3 denotes a preceding material, 4 denotes a following material, and opposing ends of the preceding material 3 and the following material 4 are abutted. It has been welded and a weld 5 is formed there. A pair of distance measuring devices 61, 62,
For example, two-dimensional laser distance meters 61 and 62 are provided. These distance meters 61, 62 are provided in close proximity to the trimmer cutting tool as shown in FIGS. 2 and 3, especially FIG. That is, the steel strip is butt-welded between the fixed base 7 and the movable base 8 by the entry and exit electrodes 1 and 2, and the welding beads are formed by upper and lower trimming tools 91 and 1.
01 and trimmed. Each byte 9
Reference numerals 1 and 101 are held by cutting tool holders 11 and 12 of an upper carriage 9 and a lower carriage 10, respectively, of the trimmer (see FIG. 3). Distance meters 61 and 62 are provided immediately after the bite holders 11 and 12, respectively. In this way, the welded portion after the butt is trimmed, and immediately thereafter, the distance to the welded surface along the weld line can be continuously measured.

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 displays the sectional profile of the welded portion and the difference in level. , Bead remaining, etc. are displayed. Further, the information processing device 13 compares the pass / fail judgment reference value input in advance with the measurement data, and issues an alarm when the welding shape is defective, for example, when the welding is wrong (level difference).

That is, according to the present invention, the distance to the surface in the direction perpendicular to the welding line, that is, in the cross section of the welded portion, is measured by the distance meters 61, 62 provided behind the cutting tools 91, 101 of the trimmer. For example, measurement can be performed at intervals of 0.2 mm and an image can be displayed on the display device 14 as a cross-sectional shape. On the other hand, the measurement cycle can be made constant, for example, 60 times / second, so that 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, the amount of misalignment (the difference in the level of the butting surfaces of the steel strips) can be detected. Also, by comparing the data at the above-mentioned fixed position with the data up to the center of trimming, it is possible to detect the remaining bead (remaining trimming). More specifically, FIG. 4 shows a welded portion 5 of the preceding material 3 and the following material 4 butt-welded. In the welded portion 5, the dotted line portion of the bead is trimmed as a trimming portion 51, and the surfaces of the preceding and succeeding mother plates 31 and 41 remain 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 plate surfaces 31, 41 are formed in the same cross-sectional shape, and the image is displayed on the display device 14. In addition to the displayed distance data, when these distance data are compared, as shown in FIGS. 5 and 6, the amount of misalignment (e) and the remaining bead (B) can be easily obtained.

First, the amount of misalignment (e) is detected according to the principle shown in FIG. When the thicknesses of the preceding and succeeding materials 3 and the succeeding material 4 are known, each thickness is also t.
_1, and t _2. At this time, if the measurement distances at the fixed points before and after the trimming unit 51 are obtained as a, b or c, d by the distance meter 61 or 62, the misalignment amount (e) is expressed by the number 1 or 2 of the separate sheet. .

[0014]

(Equation 1)

[0015]

(Equation 2)

For this reason, the misalignment amount (e) can be detected by inputting the plate thicknesses t ₁ and t ₂ into the information processing device 13 in advance as coil information. If the 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 from the number 3 of the separate sheet.

[0017]

(Equation 3)

The remaining beads (B) are detected according to the principle shown in FIG. Front and rear the cross section of the welded portion 5 around the trimming portions 51, upper and lower 4 Tsunozo - down 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
Remaining (B) ', that is, the level difference between the cutting tool bit surface and the base plate surface is detected.

When the amount of misalignment and the remaining bead are obtained for each cross section of the welded portion as described above, these pass / fail judgment criteria are input to the information processing device 13 in advance. Compared with the reference, if the shape is defective, an alarm is issued and welding is performed again or cutting is restarted.

The shape measuring device can be made of any device as long as the distance can be measured. However, as shown in FIG. 7, it can be formed as a laser distance meter. That is, in FIG. 7, reference numerals 3 and 4 denote a leading material, a following material, and 5 a welded portion, for example, a semiconductor laser 20 and a collimator 21.
After that, the laser beam is irradiated 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 above in detail, the present invention relates to a method and an apparatus for detecting the shape of a welded portion at the time of butt welding of a steel strip. After trimming the weld, the cross-sectional shape perpendicular to the weld line of the weld is continuously measured from the front and back surfaces of the weld near the weld after the trim along the weld line, and the shape measurement data is compared. Then, the amount of misalignment of the preceding and following steel strips and the remaining beads in the welded portion are detected. Further, in detecting the shape of such a butt welded portion, the butt welded portion is disposed opposite to the upper surface and the lower surface of the welded portion immediately after the trimmer cutting tool of the welding machine for butt-welding the opposed end surfaces of the preceding and following steel strips. And a shape measuring device that continuously measures the cross-sectional shape of the welded section perpendicular to the weld line, and compares the shape measurement result with the thickness information of both steel strips to calculate the amount of misalignment and And an information processing device for detecting a remaining code.

Therefore, according to the present invention, there is a strong tendency that an open end of a plate is not straightened in a wide and thin butt joint, assuming that inspection accuracy which cannot be achieved by the prior art can be guaranteed. That is, the amount of misalignment and the direction of misalignment tend to fluctuate. In this method, since the plate surface and the bead surface are always measured directly from both surfaces, a detailed change in shape can be accurately tracked in this case as well. Furthermore, by automating the shape inspection of the welded part, it is possible to contribute to the prevention of welding rupture in the cold rolling by welding quality assurance and the subsequent continuous annealing process, and to speed up the cold inspection by speeding up the welding inspection and re-welding. The downtime of rolling can be reduced. Also,
Since the inspection work can be omitted, the load on the operator is reduced. Furthermore, the welding conditions can be established and equipment management can be performed efficiently by quantitative welding shape data.

[Brief description of the 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. 2;

FIG. 4 is an explanatory diagram of a shape factor detected in the present invention.

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

FIG. 6 is an explanatory view of a principle of measuring a bead residue of a weld bead.

FIG. 7 is a perspective view of a laser distance meter as an example of the shape measuring device.

[Explanation of symbols]

 Reference Signs List 3 preceding material 4 trailing material 5 welded portion 13 information processing device 14 display device 61 shape measuring device 62 shape measuring device

────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI G01S 17/08 G01B 11/24 C (56) References JP-A-5-115903 (JP, A) JP-A-5-8049 ( JP, A) JP-A-4-197523 (JP, A) JP-A-4-1577091 (JP, A) JP-A-49-119430 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 15/00 B23K 9/025 B23K 37/08 G01B 11/24 G01S 17/08 B21C 51/00

Claims (3)

(57) [Claims] 1. A cross section perpendicular to the welding line of a welded portion from the front and back surfaces near a welded portion after the butt welding of the opposing end surfaces of the preceding and following steel strips, and then trimming the weld bead. The shape is continuously measured along the welding line, and the shape measurement data is compared and calculated to detect the difference between the preceding and following steel strips and the remaining beads in the welded portion. Method for detecting the shape of the weld during butt welding. 2. A steel strip welding machine for butt-welding opposing end faces of a preceding and a succeeding steel strip and trimming a bead of the welded part, immediately after the trimming tool to be trimmed, upper and lower surfaces of the welded part. Is arranged opposite to
A shape measuring device for continuously measuring a cross-sectional shape perpendicular to the weld line of the welded portion along the weld line, and comparing the shape measurement result with the thickness information of both steel strips, performing the preceding and following steps An information processing device for detecting an amount of misalignment of a steel strip is provided. 3. The apparatus according to claim 2, wherein said shape detecting device is a laser range finder.