JPH10160451A - Device for discriminating cause of abnormality of butt weld part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device which can discriminate the acceptance/rejection of a butt weld part between the facing end sections of preceding and succeeding steel strips and the cause of abnormality. SOLUTION: The management of facility is made easier and the fracture of butt weld parts in succeeding processes is prevented and, at the same time, the speeds of weld inspections and rewelding of butt welds are increased by discriminating the acceptance/rejection of a weld part 5 and the cause of abnormality based on preset criteria for discriminating the acceptance/rejection and cause of abnormality by intermittently measuring the cross-sectional shape of the weld 5 from both the front and rear surface sides after butt welding is completed and weld beads are trimmed and finding the dislocation between preceding and succeeding steel strips 4 at the weld part 5 by comparing and computing measured shape data, and then, computing the inclination, mean value, standard deviation, and residual of the dislocation based on the dislocation and comparing the computed data with preset thresholds for the mean value, standard deviation, inclination, and residual.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butt welding of a tail end of a preceding material and a leading end of a following material before a steel strip is continuously passed through a cold rolling mill or the like. The present invention relates to a device for determining the cause of abnormality of a unit.

[0002]

2. Description of the Related Art Generally, in a cold rolling line, a pickling line, and the like, prior to continuous processing, opposite ends of a steel strip of a preceding material and a succeeding material are butt-welded to make the steel strip continuous.
Subsequent processes are continuously passed. The butt-welded portion needs to maintain the same shape condition as the base material, that is, high-precision butt accuracy, so as not to be broken in the subsequent process, that is, the pickling line or the cold rolling line.

[0003] For this reason, regarding the shape of the butt-welded portion, whether or not there is a step (bead remaining) 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 the trimmer and detect the shape of the weld immediately after trimming the weld bead (Iron Research No. 307, p. 35).
This shape detection device slides a contact pressed against the surface of a weld to be measured along a welding line, detects the amount of vertical movement of the contact at the time of this sliding with a differential transformer, and detects the desired amount. This is a device that detects and welds the shape by amplifying and recording according to the shape. If this shape detector is continuously arranged at a predetermined pitch in the weld cross-sectional direction, the cross-sectional shape of the weld can be continuously inspected at the same time as trimming, but the mechanical and complicated structure has a short life. In addition, it is difficult to maintain, the measurement accuracy is low, the predetermined measurement accuracy cannot be obtained, and the detailed cross-sectional shape for obtaining the deformation state of the plate before and after the trimming part is not obtained. I have.

[0004] As a method of solving the above-mentioned drawbacks, as a method of butt-welding the opposite ends of the preceding and following steel strips, the weld bead is trimmed, and then the weld bead is welded from the front and back surfaces in the vicinity of the welded portion after the trimming. The cross-sectional shape perpendicular to the weld line at the weld is continuously measured along the weld line, and the shape measurement data is compared and calculated to determine the amount of misalignment between the leading and trailing steel strips at the weld (displacement of the butted portion). Amount and bead residue detection method and apparatus (Japanese Unexamined Patent Publication No.
154510).

[0005]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 5-154 is disclosed.
The method and apparatus disclosed in Japanese Patent Publication No. 510 is an excellent invention capable of accurately detecting the difference between the leading and trailing steel strips in the welded portion and the remaining beads, but setting the height of the leading and trailing members. It is not possible to determine the cause of an abnormality in the weld, such as a defect, a foreign object being caught between the electrode clamp and the steel strip, etc., so it is not possible to respond promptly even if an abnormality occurs in the weld, and it takes time to maintain the equipment. There is a disadvantage that.

An object of the present invention is to solve the above-mentioned problem described in Japanese Patent Application Laid-Open No. H5-1545.
No. 10 discloses a method and an apparatus disclosed in Japanese Patent Publication No.
It is an object of the present invention to provide an apparatus for determining the cause of an abnormality in a butt welded portion, which can determine the pass / fail of the butt welded portion at the opposite end of the preceding and following steel strip and the cause of the abnormality.

[0007]

SUMMARY OF THE INVENTION An apparatus for determining the cause of an abnormality in a butt weld portion according to the present invention is a butt-weld of a trimmer cutting tool for butt-welding opposing ends of a preceding material and a following material and trimming a bead of the weld portion. A shape measuring device that is arranged opposite to the upper surface and the lower surface of the weld portion later, and that intermittently measures a cross-sectional shape perpendicular to the weld line of the weld portion along the weld line, and shape measurement data of the shape measuring device. The difference between the preceding material and the following material in the sheet width direction and the remaining bead are detected based on the inclination, the average value, the standard deviation, and the residual value of the difference between the preceding material and the following material in the sheet width direction. Is calculated and compared with preset threshold values of the amount of misalignment, the average value, the standard deviation and the residual value, and based on preset weld pass / fail and abnormality cause determination criteria, the pass / fail of the butt weld is determined. And cause of abnormality Comprising a specific to the information processing apparatus. Thus, based on the amount of misalignment in the width direction between the preceding material and the succeeding material detected by the welded part shape detecting device at the time of butt welding, the inclination, average value, standard deviation, Calculate the residual, compare it with the preset slope, average value, standard deviation and each threshold of residual error, and based on the preset weld pass / fail and abnormality cause determination criteria, butt weld By specifying the pass / fail of the failure and the cause of the abnormality, the cause of the abnormality is the difference between the working side and the drive side of the leading material and the following material, the height setting failure of the leading material and the following material, the gap between the electrode clamp and the material. It is possible to determine whether the cause is a bite of a foreign object or a warp of a material. Therefore, when an abnormality occurs in the welded portion, a quick response can be made according to the cause of the abnormality, and the maintenance and management of the equipment is facilitated.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The shape measuring apparatus used in the present invention is not particularly limited as long as it can measure the distance to the surface of a weld without contacting the weld.
As shown in FIG. 11, an optical distance meter, for example, a laser distance meter, that is, a laser beam is applied to the welding portion 5 via a semiconductor laser 51 and a collimator 52, and the reflected light is received by an image sensor 54 via a lens 53. It is advisable to use a two-dimensional one that can measure the distance.

In the present invention, the pass / fail of the butt-welded portion and the determination of the cause of the abnormality are determined in advance by setting the slope of the misalignment amount, the average value, the standard deviation, and the threshold value of the residual, and then detecting the shape by the welded portion detecting device. Based on the amount of misalignment in the sheet width direction of the preceding material and the succeeding material, the inclination of the amount of misalignment, the average value, the standard deviation and the residual are calculated in the information processing apparatus, and the inclination of the amount of misalignment set in advance, The threshold value is compared with the average value, the standard deviation, and the residual value. For example, binarization is performed based on whether the threshold value is larger or smaller than the threshold value. And the cause of the abnormality are determined.

In the present invention, the preset thresholds of the amount of misalignment, the average value, the standard deviation, and the residual are set to the slope, average value, standard deviation, and residual of the amount of misalignment obtained in the normal state of the welded portion. Each average value or each standard deviation based on the results can be adopted.

[0011]

【Example】

Embodiment 1 Hereinafter, details of the present invention will be described with reference to FIGS. FIG. 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. 3 is a side view from the XX direction of FIG. , FIG. 4 is an explanatory view of a shape factor detected by the present invention,
FIG. 5 is an explanatory view of the principle of measuring the difference between the preceding material and the following material, FIG. 6 is a perspective view showing an outline of measurement points of the difference between the preceding material and the following material, and FIG. FIG. 8 is a graph showing the relationship between the sheet width position and the amount of misalignment in the case of the height setting failure of FIG. FIG. 9 is a graph showing the relationship between the width and the amount of misalignment when a foreign object is caught between the electrode clamp and the steel strip, and FIG. 10 is a graph showing the measurement of the remaining bead of the weld bead. It is explanatory drawing of a principle.

In FIG. 1, 1 is an outgoing electrode, 2 is an incoming electrode, 3 is a preceding material, 4 is a succeeding material, and opposing ends of the preceding material 3 and the succeeding material 4 are butt-welded to form a welded portion. 5 are formed. A pair of upper and lower distance measuring devices 6, 7 such as two-dimensional laser distance meters 6, 7 are provided with the welded portion 5 interposed therebetween.
As shown in FIGS. 2 and 3, the pair of upper and lower distance measuring devices 6 and 7 are provided adjacent to the trimmer cutting tool. That is, the steel strip is butt-welded between the fixed base 8 and the movable base 9 by the entry electrode 2 and the exit electrode 1, and the weld bead is cut and trimmed by the upper and lower trimming tools 10, 11. Each trimming byte 10,
3, the tool holders 1 of the upper carriage 12 and the lower carriage 13 of the trimmer as shown in FIG.
4 and 15 are held. This tool holder 14,
By providing the distance measuring devices 6 and 7 immediately after 15, the distance to the surface of the weld 5 along the welding line can be measured intermittently immediately after the butt weld 5 is trimmed.

The distance information from each of the distance measuring devices 6 and 7 is sent to the information processing device 16. Information processing device 16
Calculates the inclination, the average value, the standard deviation, and the residual value of the misalignment amount in the plate width direction based on the distance information from each of the distance measuring devices 6 and 7. The information processing device 16 calculates the inclination, the average value, the standard deviation, and the residual value of the misalignment amount in the sheet width direction, and the inclination, the average value, the standard deviation, and the inclination amount of the misalignment amount in the sheet width direction set in advance. Binary classification is performed by comparing each threshold value of the residuals, and the remaining beads are calculated and compared with a preset threshold value of the remaining beads. Further, the information processing device 16 determines the acceptability of the welded portion 5 based on these processing results, the welded portion acceptance / rejection, and the abnormality cause determination criterion. It is configured to specify and display on the display device 17.

With the above configuration, the distance measuring devices 6 and 7 provided behind the trimming tools 10 and 11 of the trimmer allow the distance to the surface perpendicular to the welding line, that is, in the lateral direction of the welding portion, to the surface thereof. The distance can be measured at intervals of, for example, 0.2 mm and an image can be displayed on the display device 17 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, by comparing data at a certain distance before and after the trimming portion in the measured distance, it is possible to calculate the amount of misalignment (a difference in the level of the steel strip butted surface). Also, by comparing the data at the above-mentioned fixed distance with the data up to the center of trimming, the remaining bead (remaining trimming) can be calculated.

More specifically, as shown in FIG. 4, the leading member 3 and the trailing member 4 are butt-welded, and the dotted line portion of the bead of the welded portion 5 is trimmed as a trimming portion 41. The surfaces 3a, 4a of the preceding material 3 and the following material 4 are connected adjacent to each other. Therefore, on the removal surface 42 of the trimming portion 41, the profile is displayed on the display device 17 as described above, and the removal surface 42 and the surfaces 3a, 4a of the preceding material 3 and the following material 4 have the same cross-sectional shape. , Is displayed on the display device 17, and when these distance data are compared,
As shown in FIGS. 5 and 10, the misalignment amount (e) and the remaining bead (B) can be easily obtained.

That is, the amount of misalignment (e) is calculated according to the principle shown in FIG. If the sheet thicknesses of the preceding material 3 and the succeeding material 4 have been input to the information processing device 16 from a higher-level computer or the like, the respective thicknesses are assumed to be t ₁ and t ₂ , respectively. When the measured distances at the fixed points before and after the trimming unit 41 detected by 6 and 7 are input as a, b or c, d, the amount of disparity (e) is obtained by the following equation (1) or (2). be able to. e = (ba) + (t ₁ −t ₂ ) / 2 (1) Equation e = (cd) + (t ₂ −t ₁ ) / 2... Equation (2)

If the thicknesses of the preceding material 3 and the following material 4 are unknown, the measurement distances at the fixed points before and after the trimming portion 41 detected by the upper and lower distance measuring devices 6 and 7 are a, b or When c and d are input to the information processing apparatus 16, the disparity amount (e) can be obtained by the following equation (3). e = {(ab)-(cd)} / 2 Equation (3)

Further, the information processing apparatus 16 calculates the difference (e) between the fixed points before and after the trimming section 41 obtained as described above based on the result of measuring N points in the width direction as shown in FIG. The slope (e _K ), average value (e _AV ), standard deviation (e _ST ), and residual (e _RE ) of the amount of misalignment (e _i ) are calculated by the equations (4) to (7) shown below.

[0019]

(Equation 1)

[0020]

(Equation 2)

[0021]

(Equation 3)

[0022]

(Equation 4)

When the height setting of the preceding material 3 and the succeeding material 4 is not good, as shown in FIG. 7, the average value (e _AV ) of the misalignment amount.
Becomes larger. Further, the preceding material 3 when the height level of the next strip 4 is different in the working side (FS) and the drive side (DS), shown in Figure 8, the tongue and groove of inclination (e _K) The standard deviation (e _ST ) increases. Furthermore, if foreign matter is caught between the electrode clamp and the strip,
When warpage occurs in the following material 4 or as shown in FIG.
The standard deviation (e _ST ) and residual (e _RE ) of the amount of misalignment increase. Therefore, the threshold (e _K ), the average (e _AV ), the standard deviation (e _ST ), and the residual (e _RE ) thresholds of the amount of misalignment (e _i ) input in advance to the information processing device 16 and , The slope (e _K ), the average value (e _AV ), the standard deviation (e _ST ), and the residual (e _RE ) of the disparity amount (e _i ) obtained as described above.
Preset welding pass / fail and abnormality cause determination criteria,
For example, the presence / absence of an abnormality in the welded portion 5 and the cause of the abnormality can be identified by making a determination based on the welding pass / fail and abnormality cause determination criteria shown in Table 1 in which a binary classification of larger or smaller than each of the thresholds is performed. it can. In the column of the cause of the weld failure in Table 1, A represents the working side (FS) and the driving side (DS).
B indicates that the height of the preceding material 3 and the succeeding material 4 are not properly set, and C indicates that a foreign material is caught between the electrode clamp and the strip or that warpage occurs in the steel strip. In Table 1, large and small binary classification is performed. However, if multi-valued classification such as large, medium and small is performed, more detailed state analysis can be performed.

[0024]

[Table 1]

Further, as shown in FIG. 10, the remaining bead (B) is obtained by dividing the cross section of the welded portion 5 into four zones Z ₁ , Z ₂ , Z ₃ , Z ₃ around the trimming portion 41. Divided into _four
Each zone _{Z 1, Z 2, Z 3} , Z and all distance values measured by the upper and lower distance measuring devices 6 and 7 for _4, each zone _{Z 1, Z 2, Z 3} , the distance in Z ₄ to d From the deviation from
The remaining bead (B), that is, the step amount between the 41-byte surface of the trimming portion, and the surfaces 3a and 4a of the preceding material 3 and the following material 4 are obtained. Therefore, by comparing the threshold value of the remaining bead set in advance in the information processing device 16 with the remaining bead (B) obtained as described above, pass / fail is determined. If the result is unacceptable, the bead cutting is performed again.

Example 2 The abnormality cause determination device of Example 1 was installed in the flash butt welding machine on the entry side of a cold tandem rolling mill consisting of five stands, and the inclination (e _K ) of the misalignment amount and the average value ( e _AV ), the standard deviation (e _ST ), and the residual (e _RE ) thresholds, the slope (e _K ), average value (e _AV ), standard deviation (e _ST ), residual A method of discriminating the size by adopting the value of each standard deviation × 1 of the difference (e _RE ) is adopted, and the plate thickness is 1.6 to 4.5.
mm, the number of butt welding of steel strips with a width of 610 to 1270 mm, 12,000 times of butt welding, determination of the normality and abnormality of the welded part and the main causes of welding abnormality at the time of abnormality are identified, and the defect occurrence rate and judgment hit rate I asked. Table 2 shows the results.

[0027]

[Table 2]

As shown in Table 2, the occurrence rate of welding abnormality is 0.16%, and the predictive predictive value of the main cause of welding abnormality is:
The level difference between the working side and the driving side was 95%, the input side electrode height setting failure was 93%, and the foreign matter was trapped by 82%.

[0029]

The apparatus for determining the cause of an abnormality in a butt-welded part according to the present invention not only determines the pass / fail of a butt-weld part,
Since the cause of the abnormality in the welded portion can be determined, facility management is facilitated, the breakage of the welded portion in the next process can be prevented, and the speed of welding inspection and re-welding can be increased.

[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 XX 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 a principle of measuring a difference between a preceding material and a following material.

FIG. 6 is a perspective view illustrating an outline of a measurement point of a difference amount between a preceding material and a following material.

FIG. 7 is a graph showing the relationship between the sheet width position and the amount of misalignment when the height setting of the preceding material and the succeeding material is defective.

FIG. 8 is a graph showing the relationship between the plate width position and the amount of misalignment when the heights of the preceding material and the following material are different on the working side and the driving side.

FIG. 9 is a graph showing a relationship between a plate width position and a misalignment amount when a foreign substance or the like is caught between an electrode clamp and a steel strip.

FIG. 10 is an explanatory diagram of a principle of measuring a bead residue of a weld bead.

FIG. 11 is a perspective view of a laser distance meter as an example of the shape measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outgoing electrode 2 Inlet electrode 3 Leading material 4 Trailing material 5 Welded part 6, 7 Distance measuring device 8 Fixed base 9 Moving base 10, 11 Trimming tool 12 Upper carriage 13 Lower carriage 14, 15 Tool holder 16 Information processing device 17 Display device 41 Trimming part 42 Removal surface 51 Semiconductor laser 52 Collimator 53 Lens 54 Image sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // B21B 15/00 B21B 15/00 A (71) Applicant 000001199 Kobe Steel, Ltd. 1-chome, Wakihama-cho, Chuo-ku, Kobe City, Hyogo Prefecture No. 3-18 (72) Inventor Satoshi Machida 1850 Minato, Wakayama City, Wakayama Prefecture Sumitomo Metal Industries Co., Ltd.Wakayama Steel Works (72) Inventor Matsuo Yoshimoto 1 Kobe Town, Fukuyama City, Hiroshima Prefecture Fukuyama Steel Works Co., Ltd. 72) Inventor Remodeling Okamoto 1-chome, Mizushima Kawasaki-dori, Kurashiki-shi, Okayama Pref. Inside Mizushima Steel Works, Kawasaki Steel Co., Ltd. (72) Inventor, Fumihide Nozaki 1 Kanazawacho, Kakogawa-shi, Hyogo Prefecture Inside

Claims (1)

[Claims] 1. The welding method according to claim 1, further comprising: butt-welding the opposing ends of the preceding material and the following material, and after the trimmer cutting tool for trimming a bead of the weld, facing the upper surface and the lower surface of the weld. A shape measuring device that intermittently measures a cross-sectional shape along a welding line of a weld line of a portion, and a sheet width direction of the preceding material and the following material based on shape measurement data measured by the shape measuring device. Of the misalignment of the preceding material and the succeeding material in the sheet width direction, and calculates the inclination, the average value, the standard deviation, and the residual of the preceding material and the succeeding material, and calculates a predetermined inclination of the misalignment. , An average value, a standard deviation, and an information processing device that sequentially compares the threshold with each of the residuals, and specifies the pass / fail of the butt weld and the cause of the abnormality based on preset welding pass / fail and abnormality cause determination criteria. Pier characterized by Device for determining the cause of abnormalities in welded joints.