JPS63180853A - Strip weld strength measuring apparatus - Google Patents

Abstract

PURPOSE:To prevent a fracture trouble at a strip weld part, by arranging a transmission probe and a reception probe sandwiching a strip weld part and a means for making a weld part position coincide with a flaw detection measuring position to measure the strength of the weld part accurately. CONSTITUTION:A transmission probe 14 and a reception probe 16 are arranged sandwiching a weld part 12 between the preceding strip 10 and the subsequent strip 11. A liquid feed tube is provided to jet a contact medium to a flaw detecting position. Then, strips 10 and 11 are moved and a flaw detection measuring position is determined between the weld part 12 and the transmission probe 14 and the reception probe 16 by a positioning means 22. Thereafter, the strips 10 and 11 are fixed by a fixing means 24. An ultrasonic wave W is transmitted from the transmission probe 14 to propagate through the preceding strip 10, the weld part 12 and the subsequent strip 11 and received with the reception probe 16. Acceptance and rejection of the weld part are judged from the received echo level thereof. Thus, the transmission and reception probes are arranged on both sides of the weld part to detect flaws, thereby enabling highly accurate measurement of the quality of the weld part on line.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a strip weld strength measuring device, and in particular,
The present invention relates to a strip weld strength measuring device for online measuring the strength of a welded part of a continuous strip by welding, which is suitable for use in a continuous line that handles metal coils such as thin plate coils and wire coils.

[Conventional technology]

Conventionally, a welding machine has been installed in a continuous line that handles thin plate coils and wire coils, and is designed to automatically weld the leading strip and the trailing strip. FIG. 10 shows a simplified version of this continuous line. In this continuous line, the leading strip 1 and the trailing strip 2 are welded by a welding machine 3 installed in the middle of the line, and the strip 1.2 is welded through the welded part 4.
will be passed through continuously. Here, during welding by the welding process 8!3, the strip 1.
If the shape of the welded edge 2 is bad or the welding conditions are insufficient, the welding strength of the welded part will be lower than that of the base metal, and it will not be able to withstand the line tension, causing the welded part 4 to Accidents of breakage will occur. On the other hand, as a method for automatically inspecting the welded part online, for example, Japanese Patent Application Laid-Open No. 58-151974
As disclosed in the above publication, a system has been proposed that detects magnetic fields at a plurality of points along the entire length of a welded part during welding, and tests whether welding is good or bad based on the magnetic field detection output. Specifically, in flash butt welding, this weld inspection method uses multiple magnetic detection elements to detect the magnetic field, because if the current flowing through the strip becomes non-uniform, the magnetic field generated around the strip also becomes non-uniform. Through this detection, the current distribution within the strip during welding is known, and inspection is performed by determining whether welding is good or bad based on this current distribution.

[Problems to be solved by the invention]

However, the method proposed in Japanese Unexamined Patent Publication No. 58-151974 has the following problems. Since the welding part detector is built into the welding equipment body,
There is a problem that the welding machine body becomes large. Further, since the magnetic detection device is built into the electrode, there is a problem that it cannot be applied to a welding machine having a wheel-type electrode such as a seam welding machine. In addition, the welded part is not directly inspected, but the current distribution during welding is measured and defects in the welded part are determined based on this current distribution, so it is an indirect inspection method, and the inspection There is a problem that accuracy is reduced.

[Purpose of the invention]

The present invention has been made in view of the above conventional problems, and it is possible to accurately measure the strength of the weld between the leading strip and the trailing strip in a continuous line that handles metal strips. It is an object of the present invention to provide a strip welding strength measuring device that can prevent strip breakage accidents from welded parts caused by insufficient strength due to poor welding of the welded parts.

[Means to solve the problem]

The present invention provides a strip welding strength measuring device that measures the strength of a welded part of a continuous strip by welding online. A two-probe ultrasonic flaw detector in which a probe is arranged, a liquid supply pipe that injects couplant to a strip near the ultrasonic flaw detector, and at least one of the welded portion or the ultrasonic flaw detector are moved. Let me,
a welding part positioning means for matching the welding part with a predetermined flaw detection measurement position between the transmitting probe and the receiving probe; and a fixing means for fixing the strip near the welding part after positioning by the welding part positioning means. The above-mentioned object is achieved by having a determining means for determining whether or not the weld is broken based on the output signal from the two-probe ultrasonic flaw detector. (Function) In the present invention, a two-probe type ultrasonic flaw detector in which a transmitting probe is placed on one side in the strip movement direction and a receiving probe is placed on the other side with the welded part in between is used to detect the welded part. Therefore, compared to the conventional method of determining whether welding is good or bad based on the current distribution flowing through the strip during flash butt welding, welds can be directly inspected using ultrasonic flaw detection. It is possible to improve the measurement accuracy of welding strength.Moreover, the ultrasonic flaw detector can be configured to have a transmitting probe and a receiving probe as separate bodies to detect reflected waves and incident waves. Therefore, compared to the one-probe method, the echo level can be obtained on the safe side with less noise, so reliability can be improved.Furthermore, the method includes the welding part positioning means, fixing means, and determination means. This allows the welding strength of the welded part to be constantly and fully automatically evaluated. Therefore, by feeding back this measurement result to the line operation, it is possible to prevent strip breakage accidents due to insufficient strength of the welded part. [Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, as shown in Figs. , a strip welding strength measuring device for online measuring the strength of a welded portion 12 of a trailing strip 11, in which a transmitting probe 14 is placed on one side in the strip movement direction with the welded portion 12 in between.
, a two-probe ultrasonic flaw detector 18 with a receiving probe 16 disposed on the other side, a liquid supply pipe 20 for injecting couplant onto the strip 10.11 near the ultrasonic flaw detector 18; a welding part positioning means 22 for moving the ultrasonic flaw detector 18 to match the welding part 12 with a predetermined flaw detection measurement position between the transmitting probe 14 and the receiving probe 16; and this welding part positioning means fixing means 24 for fixing the strip 10.11 in the vicinity of the weld 12 after positioning by 22;
Judgment means (not shown) for judging breakage of the welded part 12 based on the output signal from the two-probe ultrasonic flaw detector 18
a control tall device 26 that controls the positioning means 22 and the fixing means 24, the ultrasonic flaw detector 18, the liquid supply pipe 20, the welding part positioning means 223, and the fixing means 2.
4 is incorporated into a main frame 28 having an overall inverted U-shape. In addition, the symbol W in the figure indicates the ultrasonic wave transmitted from the transmitting probe 14, 27 indicates a cooler for cooling the control device 2G, and 29 indicates the main frame 28.
The protectors to prevent damage to each type of equipment installed on the equipment are shown below. The ultrasonic flaw detector 18, as shown in FIG. ing. Specifically, a large number of transmitting probes 14 are connected to the welded portion 12.
They are arranged in a line at a predetermined pitch in the strip width direction within the presser frame 36 so as to follow the strip width direction. Similarly to the transmitting probes 14, a large number of receiving probes 16 are also placed along the welded portion 12 in the strip width direction within the holding frame 36 at predetermined widths 9--3. = −δ − They are arranged in a line. Note that the individual transmitting probes 14 and receiving probes 16 are paired in the longitudinal direction of the strip. Each of the probes 14, 16, as shown in FIG.
It is supported by a support rod 32 in a vertically movable manner within a presser frame 36, and is configured to be pushed downward by a coil spring 34. The liquid supply pipe 20 is connected to the side wall 36A of the presser frame 36.
The injection nozzle is attached to the presser frame 36 so that the injection nozzle is located between the transmitting probe 14 and the receiving probe 16. As shown in FIG. M1, the fixing means 24 includes a presser frame 36 that is vertically movable above the strips 10, 110, and a strip 10.11.
The coil guide 38 is movable in the vertical direction below the presser frame 36, and the coil guide 38 is pushed downward and the coil guide 38 is pushed upward, and the presser frame 36 and the coil guide 38 are used to control the strips 10, 1.
1, -10- is comprised of an upper cylinder 40 and a lower cylinder 42 for holding it from above and below, and a moving frame 46 equipped with a guide part 44 that guides the presser frame 36 and coil guide 38 in the above and below directions. There is. As shown in FIG. 3, the presser frame 36 and the coil guide 38 are formed into a groove shape in cross section. The upper cylinder 40 and the lower cylinder 42 are attached to the moving frame 46. As shown in FIGS. 4 to 6, the welding part positioning means 22 includes a strip conveying device (not shown) that conveys the strip 10111, and a welding part moving distance detector that detects the moving distance of the welding part 12. 52 and the welded portion 1
a welding mark detector 50 that detects the welding mark 48 corresponding to 2 and outputs a stop signal to the unillustrated conveying device of the strip 10.11 and a measurement start signal to the welding part movement distance detector 52; Welding part movement distance detector 52
The output signal of A computer 54 that calculates the distance between the probe 14 and the reception probe 16 to a predetermined flaw detection measurement position, and a predetermined flaw detection measurement position of the ultrasonic flaw detector 18 at the welded part 12 based on the output signal of this computer 54. and a moving means 56 for moving the ultrasonic flaw detector 18 as shown in FIG.
incorporated within. As shown in FIG. 4, the welding mark 48 is constituted by a mark hole formed through the leading strip 10 at a position close to the welding part 12. As shown in FIG. 4, the welding mark detector 50 is composed of a light emitter 58 installed above the strip 10 and a light receiver 60 installed below the strip 10. The welding part movement distance detector 52 is composed of a position detection roller 62, as shown in FIG. This position detection roller 62 is rotatably attached to the tip of the swing arm 64. A spring 66 is attached to the swinging arm 64, and the position detection roller 62 is always pushed downward by the spring 66, and is configured to resiliently abut against the strip 10. . The moving means 56 includes a probe positioning member 6 connected to the moving frame 46, as shown in FIG.
8 and a lead screw @ which is screwed into a female threaded portion 70 formed in this probe positioning member 68 and moves the probe positioning member 68 in the longitudinal direction of the strip 10.11 via this female threaded portion 70. 1172, and a servo motor 78 that rotationally drives this lead screw shaft 72 via gears 74 and 76. The servo motor 78 includes an angle meter 80 and a servo amplifier 82 for feedback control. The output signal of the angle meter 80 is compared with the control signal from the computer 54, and this output signal is converted by a servo amplifier 82 into a command voltage for the servo motor 78. Next, the operation of this embodiment will be explained. First, as shown in FIG. 2, when the leading strip 10 and the trailing strip 11 are welded together by welding 130, this welded portion 12 is removed by the strip welding strength measuring device according to the present invention by the strip winding device 31. 100 ultrasonic flaw detectors 18 are sent to a predetermined position for flaw detection. This positioning of the welded portion 12 is performed by the welded portion positioning means 22. That is, as shown in FIG. 5, first, the weld mark 48 formed at the rear end of the leading strip 10 is detected by the weld mark detector 50, and based on this detection signal, the winding device is stopped. A measurement start signal is output to the signal and welding part movement detector 52. The welding part movement distance detector 52 is activated by a measurement start signal.
The moving distance x of the welding part 12 is measured based on the output of an angle meter built into the position detection roller 62. Note that the welding portion movement detector 52 can also be configured by a pulse generator attached to a line roll. Next, the distance -(X-)) indicating the positional relationship between the welded part 12 and the predetermined flaw detection measurement position is determined by the calculator 54. Specifically, λ-X, which is obtained by subtracting the distance between the welding part 12 and the welding mark 48 from the strip movement amount X detected by the welding part movement distance detector 52, is calculated by the welding mark detector 50 and the ultrasonic flaw detection. By subtracting the distance from the welding part 12 to the flaw detection measurement predetermined position, the distance (x-°C) is calculated. A positioning control signal corresponding to this distance L-(x-1) is output to the moving means 56. As shown in FIG. 6, the moving means 56 compares the positioning control signal and the output signal of the angle meter 80 to determine whether the predetermined flaw detection position of the ultrasonic flaw detector 18 matches the welded part 12. The servo motor 78 is rotationally controlled to move the probe positioning member 68 so as to move the probe positioning member 68. Thereby, the predetermined flaw detection measurement position of the ultrasonic flaw detector 18 can be located at the welded portion 12 . After the positioning of the ultrasonic flaw detector 18 is completed, the fixing means 24 is activated. That is, the presser frame 36 and the coil guide 38 are moved by the upper cylinder 40 and the lower cylinder 42 so as to sandwich the strips 10 and 11. When the strip 10.11 is held by the fixing means 24, when the presser frame 36 is pushed downward,
Transmission probe 14 attached to the law frame 36
, before the receiving probe 16 contacts the strips 10, 11, couplant is injected by the feed pipe 20 onto the surface of the strip 10, 11 in the vicinity of the weld 12. Therefore, the transmitting probe 14 and the receiving probe 16 of the ultrasonic flaw detector 18 come into contact with the strips 10 and 11 via the couplant. In this way, the ultrasonic flaw detector 18
The reason why and the strip 10111 are brought into contact is to make it easier for the ultrasonic wave W to pass through the inside of the strip 10.11. In this way, the strips 10 and 11 are fixed, and the ultrasonic flaw detector 1 is attached to the strips 10111 through the couplant.
When 8 is touched, ultrasonic flaw detection starts. This ultrasonic flaw detection is performed by the following procedure. First, as shown in FIG. 3, when the ultrasonic wave W is transmitted from the transmission probe 14, the leading strip 10, the welded part
The ultrasonic wave W is propagated to the receiving probe 16 via the trailing strip 11 . At this time, the echo level of the received wave at the receiving probe 16 changes depending on whether the welding finish of the welded portion 12 is good or bad. Therefore, it is possible to judge whether welding is good or bad based on this echo level. In other words, if the echo height of the received wave is high, it can be said that the weld is well-constructed, and if the echo height of the received wave is low, the weld has a defect. The lower the number, the larger the defects in the welded portion 12 and the higher the possibility of breakage. Therefore, the relationship between the echo height and the breaking strength of each weld is determined in advance, and from this relationship it is possible to determine whether the weld 12 is good or bad based on the echo level. Figures 7 and 8 show experimental examples of the transmitted wave T and received waves R1 and R2 when the welding part 12 is well welded and when it is defective.
R7 shows what is displayed. FIG. 7 shows a case where the welded portion 12 is good. In this case,
The echo height hl of the received wave R1 is the echo height h of the transmitted wave T.
It shows a value close to e, indicating that there are no defects in the welded portion 12 and that good welding was performed. On the other hand, FIG. 8 shows a case of poor welding. In this case, the echo height h2 of the received wave R2 is equal to the transmitted wave T.
It becomes a value smaller than the echo height ha of , and it can be seen that a defect has occurred in the welded part 12. Therefore, if the relationship between the value of the echo height h2 of the received wave R2 and the breaking strength in the case of a welding defect is determined empirically, the value of the echo height h2 of the received wave R2 can be determined to It becomes possible to determine whether or not 12 will break. FIG. 9 shows the procedure for measuring the strip welding strength in this example described above. In FIG. 9, the program starts at step 100 and enters a signal waiting state at step 102. When a flaw detection start signal and a coil use signal are output during this signal waiting state, the process proceeds to step 104. In step 104, the position of the welded portion is detected. Next, the process proceeds to step 106, where the ultrasonic flaw detector 18 is positioned. Next, the process proceeds to step 108, in which the probes 14, 16 for measuring the failure criterion load are determined. Next, proceeding to step 110, the probe 14.16 is lowered and the coil guide 38 is raised. Further, as the probes 14 and 16 descend, couplant is injected from the liquid supply pipe 20. Next, the process proceeds to step 112, and the welded part 12 is searched (U). Next, the process proceeds to step 114, and the welded part 12 is determined to be likely to break based on the fracture judgment criteria input based on the welded part flaw detection results in step 112. If it is determined in step 114 that there is a risk of breakage, the process proceeds to step 116, in which an alarm is generated and at the same time a control signal for re-welding is output to a line operating device (not shown). Next, the process proceeds to step 118, and the flaw detection device is returned to the initial position.Next, the process returns to step 102, where it waits for a signal.Furthermore, in step 114, there is a possibility that the welded portion 12 will break. If it is determined that there is no flaw detection, the process proceeds to step 120. In step 120, the signal from the welding section and the flaw detection result are output to the line operating device. Next, the process proceeds to step 118 mentioned above, and the flaw detection device is moved to the initial position. By repeating steps 102 to 120, the welding strength of the welded portion 12 can be evaluated online in a short time. Accidents can be prevented.-98 According to this embodiment, since welding defects in the welded part 12 are directly detected by the ultrasonic flaw detector 18, welding defects can be detected based on the current distribution during welding, as in the conventional method. The measurement accuracy can be improved compared to those that judge welding strength.Furthermore, the ultrasonic flaw detector 18 is a two-probe device consisting of a transmitting probe 14 and a receiving probe 16. Since the incident wave T and the reflected wave R can be detected by each probe, the echo level can be obtained on the safer side with less noise compared to the one-probe method. In particular, in this embodiment, the transmitting probe 14 and the receiving probe 16 are elastically attached to the holding frame 36 of the fixing means 24 via the support rod 32 and the coil spring 34. By being attached, each of the probes 14.16 can be brought into contact with the strip 10.11 at the same time as the strip 10.11 is fixed.In addition, the ultrasonic flaw detector 18 is installed in the holding frame 36.
By providing a liquid supply pipe 20 that injects a coupling medium onto the surface of the strip-t U-10, 11 in the vicinity of the welding part 12 that contacts the welding part 12, the passage of the ultrasonic wave W is facilitated, and the detection accuracy of welding part defects is improved. can be improved. In the above embodiment, the welding part positioning means 22 includes a welding mark detector 50 and a welding part moving distance detector 52.
, a computer 54 , and a moving means 56 , but the present invention is not limited to this, and is capable of accurately aligning the welded part 12 and the predetermined flaw detection measurement position of the ultrasonic flaw detector 18 . It may be constructed using other means of transportation as long as it is possible. [Effects of the Invention] As explained above, according to the present invention, the quality of the welded part of the strip can be measured online and fully automatically, and the measurement accuracy can be improved. have an effect. As a result, if it is determined that the strip is broken, the welded portion is welded again, thereby avoiding sudden line stoppages due to strip breakage in the continuous line, and improving productivity.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view showing an embodiment of the strip weld strength measuring device according to the present invention, Fig. 2 is a side view without showing the line configuration in the same embodiment, and Fig. 3 is the same. FIG. 4 is a cross-sectional view showing an enlarged view of the ultrasonic flaw detector and presser frame in the embodiment, and FIG. 5 is a side view including a partial block diagram for explaining the positioning operation between the ultrasonic flaw detector and the welding part in the same embodiment, and FIG. 6 is a side view including a partial block diagram in the same embodiment. FIG. 7 is a front view including a partial block diagram showing the moving means of the welding part positioning means, and FIG. Fig. 8 is a diagram showing the echo heights of the transmitted wave and the received wave in the case of a defective weld in the same example, Fig. 9 is a flowchart showing the strip welding strength measurement procedure in the same example, and Fig. 10 1 is a side view showing an example of a conventional continuous line. W... Ultrasonic wave, 10.11... Strip, 12... Welded part, 14.16... Probe, 18... Ultrasonic flaw detector, 20... Liquid supply pipe, 22 ...Welding part positioning means, 24... Fixing means, 26... Judgment means, 50... Welding mark detector, 52... Welding part movement distance detector, 54... Calculator, 56. ··transportation.

Claims (2)

[Claims] (1) In a strip welding strength measuring device that measures the weld strength of a continuous strip by welding online, a transmitting probe is placed on one side in the strip movement direction with the welded part in between, and a receiving probe is placed on the other side. a two-probe ultrasonic flaw detector in which a probe is arranged; a liquid supply pipe that injects couplant to a strip near the ultrasonic flaw detector; and at least one of the welded part or the ultrasonic flaw detector. a welding part positioning means for matching the welding part with a predetermined flaw detection measurement position between the transmitting probe and the receiving probe; and a fixing member for fixing the strip near the welding part after positioning by the welding part positioning means. and determining means for determining whether or not a weld is broken based on the output signal from the two-probe ultrasonic flaw detector. (2) The welding part positioning means includes: a strip conveying device that transports the strip; a welding part moving distance detector that detects a moving distance of the welding part; a welding mark corresponding to the welding part; a welding mark detector that outputs a stop signal to the strip conveyance device and a measurement start signal to the welding part moving distance detector; and an output signal of the welding part moving distance detector, the distance between the welding part and the welding mark, and the a calculator that calculates the distance between the welded part and a predetermined flaw detection measurement position between the transmitting probe and the receiving probe based on the distances of the weld mark detector and the two-probe ultrasonic flaw detector; Claim 1, further comprising a moving means for moving the ultrasonic flaw detector so as to locate a predetermined flaw detection measurement position of the ultrasonic flaw detector in the welded portion based on the output signal of the computer. strip weld strength measuring device.