Welding inspection device

Abstract

In a welding inspection device that inspects welded parts contained in an object by irradiating a transmitting laser beam onto a transmitting point on the object, the transmitting point is set to an appropriate location necessary for inspection. [Solution] The welding inspection device irradiates a transmitting laser beam onto a transmission point on the upper surface of the object, extracts the reflected wave generated at the transmission point and reflected off the lower surface of the object, and determines whether or not there are internal defects inside the weld based on the extracted reflected wave. The control device acquires location information of a designated receiving point and a designated inspection area, as well as information on the plate thickness and shape of the object, and uses the acquired information to calculate the effective transmission range, which is the range of transmission points that generate reflected waves that pass through the designated inspection area and reach the designated receiving point, and sets the transmission points within the calculated effective transmission range.

Description

Technical Field

[0001] The present disclosure relates to a welding inspection apparatus for inspecting welds included in an object.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2023-20336 discloses a welding inspection apparatus for inspecting weld beads included in an object. This welding inspection apparatus irradiates a plurality of transmission points on the upper surface of the object with a transmission laser beam (pulse laser beam) by scanning the transmission laser beam in a direction intersecting the extending direction of the weld bead, and among the ultrasonic waves generated at the plurality of transmission points, a reflected wave that is reflected from the lower surface of the object and reaches a reception point on the upper surface of the object is extracted on a measurement screen called a B-scope (B-scope), and when the attenuation degree of the extracted reflected wave intensity is large, it is determined that there is a defect inside the weld bead.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the welding inspection apparatus described in Japanese Patent Application Laid-Open No. 2023-20336, since the transmission laser beam is irradiated to a plurality of transmission points on the upper surface of the object for each scan of the transmission laser beam, the inspection time for one scan is the product of the number of transmission points and the irradiation period of the transmission laser beam. Therefore, if one wants to shorten the inspection time for one scan, the number of transmission points must be reduced or the irradiation period of the transmission laser beam must be shortened. However, since it is not easy to shorten the irradiation period of the transmission laser beam, it is desirable to reduce the number of transmission points as much as possible. On the other hand, if the number of transmission points is reduced too much, there is a concern that the inspection area of the object (the area where the reflected wave passes through the inside of the weld bead) will become narrow and the inspection accuracy will decrease.

[0005] Therefore, the purpose of this disclosure is to set a transmission point at an appropriate location necessary for inspection in a welding inspection device that inspects welds contained in an object by irradiating a transmission laser beam onto a transmission point on the object.

[0006] Another object of this disclosure is to set a receiving point at an appropriate location necessary for inspection in a welding inspection device that inspects welds contained in an object by detecting ultrasonic waves at a receiving point on the object. [Means for solving the problem]

[0007] The welding inspection apparatus according to this disclosure is a welding inspection apparatus for inspecting a welded part contained in an object, and comprises: a first irradiation device that irradiates a transmitting laser beam onto a transmitting point on the upper surface of the object; a detection device that detects ultrasonic waves generated at the transmitting point by the irradiation of the transmitting laser beam and reaching a receiving point on the upper surface of the object; and a control device that extracts reflected waves reflected from the lower surface of the object from the ultrasonic waves detected by the detection device and determines whether or not there are internal defects inside the welded part based on the extracted reflected waves. The control device acquires position information of a designated receiving point, which is a predetermined receiving point, position information of a designated inspection area, which is a predetermined inspection area inside the welded part, and information on the plate thickness and shape of the object, and uses the acquired information to calculate a transmission range, which is the range of transmitting points that generate reflected waves that pass through the designated inspection area and reach the designated receiving point, and sets the transmitting points within the calculated transmission range.

[0008] The welding inspection apparatus according to this disclosure is a welding inspection apparatus for inspecting a welded portion included in an object, and comprises: a first irradiation device that irradiates a transmitting laser beam onto a transmitting point on the upper surface of the object; a detection device that detects ultrasonic waves generated at the transmitting point by the irradiation of the transmitting laser beam and reaching a receiving point on the upper surface of the object; and a control device that extracts reflected waves reflected from the lower surface of the object from the ultrasonic waves detected by the detection device and determines whether or not there are internal defects inside the welded portion based on the extracted reflected waves. The control device acquires position information of a designated transmitting point, which is a predetermined transmitting point, position information of a designated inspection area, which is a predetermined inspection area inside the welded portion, and information on the plate thickness and shape of the object, and uses the acquired information to calculate a receiving range, which is the range of receiving points reached by reflected waves generated at the designated transmitting point and passing through the designated inspection area, and sets a receiving point in the calculated receiving range. [Effects of the Invention]

[0009] According to this disclosure, in a welding inspection device that inspects welds contained in an object by irradiating a transmitting laser beam to a transmitting point on the object, the transmitting point can be set to an appropriate location necessary for inspection.

[0010] According to this disclosure, in a welding inspection device that inspects welds contained in an object by detecting ultrasonic waves at a receiving point on the object, the receiving point can be set to an appropriate location necessary for the inspection. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows an example of the overall configuration of a welding inspection device. [Figure 2] This diagram shows the state of a weld bead when there are no internal defects. [Figure 3] This diagram shows the condition of a weld bead when it has internal defects. [Figure 4] This diagram schematically shows an example of a B-scope displayed on a display device. [Figure 5] This diagram shows the relationship between the transmission position and the detected intensity of the reflected wave from the bottom surface. [Figure 6] This diagram illustrates an example of a method for determining the presence or absence of internal defects in a weld bead. [Figure 7] This is a diagram (part 1) showing an example of the propagation path of a reflected wave. [Figure 8] This is a diagram (part 2) showing an example of the propagation path of a reflected wave. [Figure 9] This figure shows an example of the procedure by which the control device calculates the effective transmission range. [Figure 10] This figure shows another example of the procedure by which the control device calculates the effective transmission range. [Figure 11] This flowchart shows an example of the welding inspection process performed by the control device. [Modes for carrying out the invention]

[0012] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated.

[0013] <Overall Structure> Figure 1 shows an example of the overall configuration of the welding inspection apparatus 1 according to this embodiment. The welding inspection apparatus 1 comprises a transmitting laser source 10, a transmitting laser light irradiation device (first irradiation device) 12, a receiving laser source 16, a receiving laser light probe (second irradiation device) 18, a control device 22, and a display device 24.

[0014] This welding inspection device 1 is used, for example, to inspect a weld bead (welded portion) 6 in the welding of thin plate-shaped base materials 2 and 4. The base materials 2 and 4 are, for example, galvanized steel plates with a plate thickness of about 1 to 2 mm. Hereinafter, the base materials 2 and 4 including the weld bead 6 are also referred to as "objects". In the figure, the Y direction indicates the welding progress direction (the extending direction of the weld bead 6), the Z direction indicates the normal direction of the base materials 2 and 4, and the X direction indicates the direction orthogonal to the Y direction and the Z direction. The transmission laser light irradiation device 12 and the reception laser light probe 18 are fixed to a robot (not shown) that is movable in the Y direction (welding progress direction), and by the robot moving in the Y direction, the transmission laser light irradiation device 12 and the reception laser light probe 18 can be integrally moved relative to the base materials 2 and 4 in the Y direction.

[0015] The transmission laser source 10 generates excitation light for generating transmission laser light 14 in the transmission laser light irradiation device 12 and outputs it to the transmission laser light irradiation device 12. The transmission laser source 10 is constituted by, for example, an LD (Laser Diode) power source.

[0016] The transmission laser light irradiation device 12 receives the excitation light from the transmission laser source 10, generates transmission laser light 14 which is pulsed laser light, and irradiates the upper surface of the object (mainly the weld bead 6). The transmission laser light irradiation device 12 is constituted by including, for example, a microchip laser that generates YAG pulsed laser light and a scanning mechanism capable of scanning the irradiation position (transmission point 32) of the transmission laser light 14 in the X direction. The scanning mechanism is constituted by including, for example, a galvanometer mirror whose angle can be adjusted and a drive mechanism for driving the galvanometer mirror.

[0017] The reception laser source 16 is constituted by including a laser interferometer. The reception laser source 16 generates reception laser light 20 (reference light) that irradiates the lower base material 4 and outputs it to the reception laser light probe 18. Further, the reception laser source 16 receives the reflected light of the reception laser light 20 irradiated on the base material 4 from the base material 4 from the reception laser light probe 18, detects interference light including the reference light and the reflected light, and outputs it to the control device 22.

[0018] The receiving laser probe 18 irradiates the receiving laser beam 20 onto the receiving point 36 located on the upper surface of the base material 4 of the lower plate. The receiving laser probe 18 also receives the reflected light from the base material 4 of the receiving laser beam 20 irradiated onto the base material 4 and outputs it to the receiving laser source 16 (laser interferometer).

[0019] This welding inspection device 1 uses a laser ultrasonic method to detect internal defects in the weld bead 6. Specifically, a transmitting laser beam 14 is irradiated onto a transmitting point 32 on the upper surface of the object to generate ultrasonic waves at the transmitting point 32. Surface vibrations corresponding to the intensity of the ultrasonic waves at the receiving point 36, where a receiving laser beam 20 is irradiated, are detected by interference light between the reference light and reflected light of the receiving laser beam 20. Based on the difference in detection between when the weld bead 6 has no internal defects and when it does, the presence or absence of internal defects in the weld bead 6 is determined.

[0020] The control unit 22 consists of a CPU (Central Processing Unit), memory (RAM (Random Access Memory) and ROM (Read Only Memory)), and input / output ports for inputting and outputting various signals (none of which are shown). The CPU loads the program stored in ROM into RAM and executes it. The program stored in ROM describes the various processes to be executed by the control unit 22.

[0021] The control device 22 controls the transmitting laser source 10 to generate excitation light for generating the transmitting laser beam 14 in the transmitting laser beam irradiation device 12. The control device 22 also controls the transmitting laser beam irradiation device 12 to scan the irradiation position of the transmitting laser beam 14 in the X direction. As a result, the transmitting laser beam 14 is irradiated so as to straddle the weld bead 6. The control device 22 also receives the oscillation timing (pulse irradiation timing) of the transmitting laser beam 14 from the transmitting laser beam irradiation device 12.

[0022] The control device 22 then acquires from the receiving laser source 16 the interference measurement result of the receiving laser light 20 by the laser interferometer of the receiving laser source 16 as a signal indicating the detected intensity of the ultrasonic waves at the receiving point 36. Based on the detected intensity of the ultrasonic waves at the receiving point 36 acquired from the receiving laser source 16, the control device 22 determines whether or not there are internal defects in the weld bead 6. The method for determining whether or not there are internal defects in the weld bead 6 will be explained in detail later.

[0023] The display device 24 is a display for showing various processing results of the control device 22. The display device 24 displays a measurement screen called a B-scope, which shows the measurement results of ultrasonic waves inside the object by the welding inspection device 1.

[0024] The B-scope displays the distribution of the detected ultrasonic intensity at the receiving point 36, with the horizontal axis representing the position of the transmitting point 32 in the X direction (hereinafter also referred to as the "transmission position") and the vertical axis representing the time it takes for the ultrasonic waves generated at the transmitting point 32 by the irradiation of the transmitting laser beam 14 to reach the receiving point 36 (hereinafter also referred to as the "ultrasonic arrival time" or simply "arrival time"). On the B-scope, the distribution of the detected ultrasonic intensity is represented, for example, by a color map (changes in color or density).

[0025] The control device 22 and the display device 24 are configured, for example, by a PC (Personal Computer).

[0026] As described above, the control device 22 determines the presence or absence of internal defects in one cross-section (one XZ cross-section) of the weld bead 6 by scanning the irradiation position of the transmitting laser beam 14 in the X direction. The control device 22 then determines the presence or absence of internal defects along the entire length of the weld bead 6 by performing the inspection by scanning the transmitting laser beam 14 in the X direction once (hereinafter also referred to as "inspection of one cross-section") multiple times, while gradually shifting in the Y direction (the direction in which the weld bead 6 extends). This completes the inspection of the entire weld bead 6.

[0027] <Method for determining the presence or absence of internal defects in weld bead 6> The following describes in detail how the welding inspection device 1 determines whether or not there are internal defects in the weld bead 6. Figures 2 to 6 illustrate the principle of detecting internal defects in the weld bead 6 using the welding inspection device 1.

[0028] Figure 2 shows the state when there are no internal defects in the weld bead 6. In this welding inspection device 1, a transmitting laser beam 14 (pulsed laser beam) is irradiated onto the upper surface of the base materials 2 and 4, including the weld bead 6, and ultrasonic waves are generated at the transmitting point 32. The ultrasonic waves generated at the transmitting point 32 pass through the inside of the weld bead 6, are reflected by the lower surface 5 of the base material 4, and then reach the receiving point 36 on the upper surface of the base material 4. The receiving laser beam 20 is used to measure the minute vibrations generated at the receiving point 36 on the upper surface of the base material 4 by the ultrasonic waves that are reflected by the lower surface 5 and reach the receiving point 36 (hereinafter also called "lower surface reflected waves" or simply "reflected waves"), thereby detecting the lower surface reflected waves at the receiving point 36.

[0029] The transmission points 32, indicated by the "x" mark, are scanned in the X direction using the scanning mechanism of the transmitting laser beam irradiation device 12 (Figure 1). After measurement at a given transmission point 32 is completed, the irradiation position of the transmitting laser beam 14 is scanned in the X direction to become the next transmission point 32, and measurement is performed at the next transmission point 32.

[0030] The receiving point 36, indicated by the circle, is fixed in the X direction of the base material 4. The greater the distance in the X direction between the transmitting point 32 and the receiving point 36, the longer the propagation distance of the ultrasonic waves from the transmitting point 32 to the receiving point 36, and the intensity of the ultrasonic waves at the receiving point 36 (micro-vibrations on the surface) also decreases due to diffusion attenuation.

[0031] Figure 3 shows the state when there are internal defects 40 such as blowholes in the weld bead 6. When internal defects 40 such as blowholes are present in the weld bead 6, depending on the position of the transmission point 32, the ultrasonic waves generated at the transmission point 32 are divided into a non-passing component 41 that is scattered because its path is blocked by the internal defects 40 and does not reach the receiving point 36, and a passing component 44 that passes through the internal defects 40. In this case, the passing component 44 is reflected by the lower surface 5 of the base material 4 and reaches the receiving point 36, but the detection intensity of the lower surface ultrasonic waves at the receiving point 36 is smaller (attenuation is greater) than when there are no internal defects 40. Therefore, by capturing the degree of attenuation of the detection intensity of the lower surface ultrasonic waves at the receiving point 36, it is possible to determine whether or not there are internal defects 40 in the weld bead 6.

[0032] Figure 4 schematically shows an example of a B-scope displayed on the display device 24. Note that Figure 4 shows an example of a B-scope when there are no internal defects in the weld bead 6.

[0033] As described above, the B-scope displays the distribution of ultrasonic detection intensity at the receiving point 36, with the transmission position on the horizontal axis and the ultrasonic arrival time on the vertical axis. Therefore, the B-scope displays the transmission position, ultrasonic arrival time, and ultrasonic detection intensity on a single screen. In Figure 4, for ease of understanding, only the distribution of the maximum values ​​of the ultrasonic detection intensity at the receiving point 36 is shown as lines L1 and L2. Line L1 shows the distribution of surface waves that travel from the transmission point 32 through the surface layers of the weld bead 6 and base material 4 to the receiving point 36. Line L2 shows the distribution of bottom reflected waves.

[0034] The ultrasound detected at the receiving point 36 includes not only the bottom reflected wave (line L2) but also the surface wave (line L1). Since the propagation paths of the bottom reflected wave and the surface wave are different, the arrival times of the bottom reflected wave and the surface wave are also different. By utilizing this phenomenon, the bottom reflected wave (line L2) is extracted from the ultrasound (lines L1 and L2) that reaches the receiving point 36, excluding the surface wave (line L1). Specifically, the welding inspection device 1 sets the area indicated by the dotted line in Figure 4 as the "reflected wave extraction range," and extracts the ultrasound that reaches the set reflected wave extraction range as the bottom reflected wave.

[0035] Then, the welding inspection device 1 uses the bottom surface reflected wave extracted as described above to determine whether or not there are any internal defects 40 in the weld bead 6.

[0036] Figure 5 shows the relationship between the transmission position and the detected intensity of the reflected wave from the bottom surface. In Figure 5, line L3 represents the detected intensity of the reflected wave from the bottom surface when there are no internal defects in the weld bead 6. The detected intensity of the reflected wave from the bottom surface decreases due to diffusion attenuation as the value of the transmission position increases (the further the transmission point is from the reception point).

[0037] Line L4 represents the detection intensity of the bottom reflected wave when there is an internal defect in the weld bead 6. When the ultrasonic transmission position is greater than X1, the bottom ultrasonic waves reaching the ultrasonic receiving point pass through the internal defect in the weld bead 6. In this case, in addition to diffusion attenuation, scattering attenuation occurs at the internal defect, so the detection intensity of the bottom ultrasonic waves when there is an internal defect (line L4) is lower than when there is no internal defect (line L3). In other words, the attenuation of the detection intensity of the bottom reflected wave when there is an internal defect is greater than when there is no internal defect.

[0038] Figure 6 illustrates an example of a method for determining the presence or absence of internal defects in a weld bead 6. The welding inspection device 1 determines the presence or absence of internal defects in the weld bead 6 based on the magnitude of the attenuation of the detected intensity of the reflected wave from the bottom surface. Specifically, the welding inspection device 1 determines that there are no internal defects in the weld bead 6 if the magnitude of the attenuation of the detected intensity of the reflected wave from the bottom surface is below a predetermined threshold, and determines that there are internal defects in the weld bead 6 if the magnitude of the attenuation of the detected intensity of the reflected wave from the bottom surface exceeds the threshold. The threshold is set appropriately to a value that can distinguish the presence or absence of internal defects based on prior evaluation tests, etc. The threshold is set for each transmission position, taking into account the degree of diffusion attenuation according to the transmission position.

[0039] <Setting the irradiation range in the X direction of the transmitting laser beam 14> As described above, the welding inspection device 1 irradiates multiple transmission points 32 with a pulsed laser beam, the transmitting laser beam 14, for each inspection of one cross section (inspection by one X-direction scan). Therefore, the inspection time for one cross section is the product of the number of transmission points 32 and the irradiation period of the transmitting laser beam 14. Consequently, in order to shorten the inspection time for one cross section (and thus the overall inspection time), it is necessary to either reduce the number of transmission points 32 or shorten the irradiation period of the transmitting laser beam 14. However, since it is not easy to shorten the irradiation period of the transmitting laser beam 14 (i.e., increase the irradiation frequency of the pulsed laser), it is desirable to reduce the number of transmission points 32 as much as possible.

[0040] In view of the above, the control device 22 according to this embodiment assumes that the position of the receiving point 36 and the internal inspection area of ​​the object are specified in advance by the user or the like, acquires position information of the pre-specified receiving point 36 (hereinafter also referred to as the "specified receiving point") and position information of the pre-specified internal inspection area of ​​the object (hereinafter also referred to as the "specified inspection area"), and calculates the range of the transmitting point 32 that generates reflected waves that pass through the specified inspection area and reach the specified receiving point as the appropriate range of the transmitting point 32 necessary for inspection (hereinafter also referred to as the "effective transmission range").

[0041] Specifically, the control device 22 geometrically calculates the possible propagation paths of the reflected wave that pass through the designated inspection area and reach the designated receiving point, and calculates the effective transmission range from the possible propagation paths of the reflected wave. The propagation direction of the ultrasonic wave that propagates inside the object after being reflected from the lower surface of the object can be calculated geometrically.

[0042] Figure 7 shows an example of the propagation path of a reflected wave reaching the receiving point 36. Figure 7 shows the propagation path of a reflected wave when no mode conversion occurs during reflection (when longitudinal and transverse waves continue to propagate as longitudinal and transverse waves after reflection). Since the propagation speed of a wave that does not undergo mode conversion during reflection is constant before and after reflection, the incident angle A1 and the reflected angle A2 are equal (law of reflection). Therefore, once the position of the receiving point 36 and the position of the inspection area are determined, the propagation path of the reflected wave can be easily calculated geometrically by using the law of reflection.

[0043] In this embodiment, the propagation path of a wave that does not undergo mode change during reflection is calculated. However, the propagation path of a wave that undergoes mode change during reflection (a wave in which longitudinal and transverse waves propagate as transverse and longitudinal waves, respectively, after reflection) may also be calculated. Since the propagation velocities of longitudinal and transverse waves differ for waves that undergo mode change during reflection, the reflection angle A2 is determined by the incident angle A1 and the ratio of the propagation velocity v1 before reflection to the propagation velocity v2 after reflection. Specifically, the reflection angle A2 satisfies the relationship sinA1 / sinA2=v1 / v2. By using such a relationship, the propagation path of a wave that undergoes mode change during reflection can be calculated.

[0044] Figure 8 shows an example of the propagation paths of two reflected waves reaching the receiving point 36. Assume that the area to be inspected and the transmitting points 32A and 32B are located as shown in Figure 8. In this case, calculating the propagation path of the reflected wave 44A that originates at transmitting point 32A and reaches receiving point 36 reveals that the reflected wave 44A passes through the area to be inspected.

[0045] On the other hand, calculating the propagation path of the reflected wave 44B, which is generated at the transmitting point 32B and reaches the receiving point 36, reveals that the reflected wave 44B does not pass through the area to be inspected. Therefore, the wave from the transmitting point 32B is unlikely to be attenuated by internal defects and is not a signal necessary for defect detection based on the degree of attenuation. Thus, assuming that the receiving point 36 and the area to be inspected are predetermined, calculating the propagation path of the reflected wave makes it possible to determine whether the transmission position of the transmitting laser beam 14 is necessary for inspection.

[0046] Therefore, the control device 22 according to this embodiment acquires location information of a designated receiving point and a designated inspection area predetermined by the user, as well as information on the plate thickness and shape of the object. Using the acquired information, it calculates the possible propagation paths of the reflected wave that pass through the designated inspection area to the designated receiving point, and calculates the effective transmission range based on the calculated possible propagation paths of the reflected wave. The information on the plate thickness and shape of the object may be predetermined values, or values ​​measured in parallel with the welding inspection. The plate thickness of the object can be measured, for example, by ultrasonic inspection using a contact probe or laser. The shape of the object can be measured, for example, by a laser scanner.

[0047] Figure 9 shows an example of the procedure by which the control device 22 calculates the effective transmission range. The control device 22 acquires the position information of the designated receiving point 36R and the position information of the designated inspection area 50R, as shown in the upper part of Figure 9. The positions of the designated receiving point 36R and the designated inspection area 50R are predetermined by the user or other relevant parties. The control device 22 also acquires information on the plate thickness and shape of the object using the method described above.

[0048] The control device 22 then uses the acquired information to calculate the possible propagation paths of the reflected wave that reach the designated receiving point 36R through the designated inspection area 50R. Specifically, as shown in the lower part of Figure 9, the control device 22 calculates the propagation path of the reflected wave 44m that reaches the designated receiving point 36R while touching the boundary on the negative X-direction side (the side closer to the designated receiving point 36R) of the designated inspection area 50R, and the propagation path of the reflected wave 44M that reaches the designated receiving point 36R while touching the boundary on the positive X-direction side (the side farther from the designated receiving point 36R) of the designated inspection area 50R. The control device 22 then calculates the effective transmission range as the area with the intersection point 32m of the propagation path of the reflected wave 44m and the upper surface of the object, and the intersection point 32M of the propagation path of the reflected wave 44M and the upper surface of the object as its boundaries (both ends).

[0049] Although Figure 9 shows an example of a circular designated inspection area 50R, the shape and size of the designated inspection area are not limited to those shown in Figure 9. Furthermore, the designated inspection area does not necessarily have to be a region with an area; it may also be specified by its two endpoints (the endpoint on the negative X-direction and the endpoint on the positive X-direction).

[0050] Figure 10 shows another example of the procedure by which the control device 22 calculates the effective transmission range. As shown in the upper part of Figure 10, an example is shown where the designated inspection area is specified by the endpoint P1 on the negative side of the X direction and the endpoint P2 on the positive side of the X direction. In this case, as shown in the lower part of Figure 10, the control device 22 calculates the propagation path of the reflected wave 44m that reaches the designated receiving point 36R through the endpoint P1 on the negative side of the X direction of the designated inspection area, and the propagation path of the reflected wave 44M that reaches the designated receiving point 36R through the endpoint P2 on the positive side of the X direction of the designated inspection area. The control device 22 then calculates the effective transmission range as the area with the intersection point 32m of the propagation path of the reflected wave 44m and the upper surface of the object, and the intersection point 32M of the propagation path of the reflected wave 44M and the upper surface of the object as its boundaries (both ends).

[0051] Figure 11 is a flowchart showing an example of the welding inspection procedure performed by the control device 22.

[0052] First, the control device 22 acquires location information of a designated receiving point and a designated inspection area predetermined by the user (step S10), and also acquires information on the plate thickness and shape of the object (step S20).

[0053] Next, the control device 22 uses the information acquired in steps S10 and S20 to calculate the possible propagation paths of the reflected wave that pass through the designated inspection area to reach the designated receiving point (step S30). The specific method for calculating the possible propagation paths of the reflected wave is as described above.

[0054] Next, the control device 22 calculates the effective transmission range based on the possible propagation paths of the reflected wave calculated in step S30 (step S40). The specific method for calculating the effective transmission range is as described above.

[0055] Next, the control device 22 sets the transmission point so that it falls within the effective transmission range calculated in step S40 (step S50). This allows the transmission point to be set at an appropriate location necessary for inspecting the designated inspection area. In other words, it avoids setting the transmission point at a location that is not necessary for inspecting the designated inspection area. Therefore, the inspection can be performed efficiently.

[0056] The control device 22 according to this embodiment reduces the number of transmission points as the effective transmission range narrows. This makes it possible to shorten the inspection time for one cross-section (and consequently the overall inspection time). For example, assuming that the distance (pitch) between adjacent transmission points is constant at 0.1 mm, the number of transmission points will be 100 when the effective transmission range is 10 mm (an additional point will be added if a transmission point is also set at the starting point of the effective transmission range; the same applies below), while the number of transmission points can be reduced to 50 when the effective transmission range is narrower than 10 mm, at 5 mm. As a result, the inspection time for one cross-section when the effective transmission range is 5 mm can be shortened to half the inspection time for one cross-section when the effective transmission range is 10 mm.

[0057] Next, the control device 22 irradiates the transmission laser beam 14 to the transmission point set in step S50 to perform an internal defect inspection of the welded part of the object (step S60). The specific inspection method is as described above.

[0058] As described above, the control device 22 according to this embodiment acquires location information of a designated receiving point and a designated inspection area predetermined by the user, as well as information on the plate thickness and bead shape of the object. Using the acquired information, it calculates the possible propagation paths of the reflected wave that pass through the designated inspection area to the designated receiving point. Based on the intersection of the calculated possible propagation paths of the reflected wave and the top surface of the object, it calculates the effective transmission range and sets the transmission point within the calculated effective transmission range. This makes it possible to set the transmission point at an appropriate location necessary for inspecting the designated inspection area. In other words, it is possible to avoid setting the transmission point at an unnecessary location that is not required for inspecting the designated inspection area. Therefore, inspection can be performed efficiently.

[0059] Furthermore, the control device 22 according to this embodiment reduces the number of transmission points as the effective transmission range narrows. This makes it possible to reduce the number of transmission points while appropriately inspecting the designated inspection area, thereby shortening the inspection time for one cross-section (and consequently the overall inspection time).

[0060] [Example 1] In the above-described embodiment, an example of a transmission point setting method was explained in which the number of transmission points decreases as the effective transmission range narrows. However, the transmission point setting method is not limited to this, and the density of transmission points may be increased as the effective transmission range narrows.

[0061] For example, the number of transmission points could be set to 100 when the effective transmission range is 10 mm, and also to 100 when the effective transmission range is 5 mm. This increases the density of transmission points from 10 points per mm when the effective transmission range is 10 mm to 20 points per mm when the effective transmission range is 5 mm, which is narrower than 10 mm. As a result, the inspection accuracy (resolution) of one cross-section when the effective transmission range is 5 mm can be improved compared to the inspection accuracy of one cross-section when the effective transmission range is 10 mm, without increasing the inspection time.

[0062] [Differentiation 2] In the above-described embodiment, an example was explained in which the number of transmission points is reduced as the effective transmission range narrows, thereby shortening the inspection time for one cross-section.

[0063] However, the narrower the effective transmission range, the more inspections may be performed on the same cross-section to remove noise in each inspection. For example, assuming that the distance (pitch) between adjacent transmission points is constant at 0.1 mm, the number of transmission points will be 100 when the effective transmission range is 10 mm, while the number of transmission points can be reduced to 25 when the effective transmission range is 2.5 mm, thus shortening the inspection time for one cross-section to one-quarter. Taking advantage of this, for example, while the number of inspections on the same cross-section is 1 when the effective transmission range is 10 mm, the number of inspections on the same cross-section can be increased to four times when the effective transmission range is 2.5 mm, and noise removal can be performed by averaging the results of the four inspections. This makes it possible to remove noise in each inspection without prolonging the inspection time for each cross-section.

[0064] [Difference 3] In the above-described embodiment, an example was described in which the irradiation position of the receiving laser beam 20 is fixed, and the irradiation position of the transmitting laser beam 14 is scanned.

[0065] However, the irradiation position of the transmitting laser beam 14 may be fixed, while the irradiation position of the receiving laser beam 20 is scanned. In this case, the control device 22 acquires location information of a designated transmission point, which is a transmission point specified in advance by the user, etc., and location information of a designated inspection area, calculates the effective reception range, which is the range of reception points reached by the reflected wave generated at the designated transmission point and passing through the designated inspection area, and sets the reception point within the calculated effective reception range. This makes it possible to set the reception point at an appropriate location necessary for inspecting the designated inspection area. In other words, it is possible to avoid setting the reception point at an unnecessary location that is not necessary for inspecting the designated inspection area, thus enabling efficient inspection.

[0066] [Differentiation Example 4] In the welding inspection apparatus 1 according to the above embodiment, the receiving laser beam 20 is irradiated from the receiving laser beam probe 18 to the receiving point 36 to detect the reflected wave in a non-contact manner. However, the method for detecting the reflected wave is not necessarily limited to using the receiving laser beam 20 or being non-contact. For example, a device (contactor) that contacts the receiving point 36 to detect the reflected wave at the receiving point 36 may be placed, and the reflected wave may be detected by this device.

[0067] [Difference 5] In the welding inspection apparatus 1 according to the above-described embodiment, if the object is deformed, the position of the designated receiving point and the position of the designated inspection area may deviate from the originally assumed position, and the propagation path of the reflected wave may also deviate from the originally assumed path.

[0068] In view of this, in the welding inspection apparatus 1 according to the above embodiment, the shape of the object may be measured using a measuring device such as a laser line scanner, and if deformation of the object is confirmed from the measurement results of the measuring device, the position of the designated receiving point and the position of the designated inspection area after deformation of the object may be calculated using the measurement results of the measuring device, the possible propagation paths and effective transmission range of the reflected wave may be recalculated using the calculated position of the designated receiving point and the position of the designated inspection area after deformation, and the transmission point may be set within the recalculated effective transmission range. This makes it possible to set the transmission point at an appropriate location necessary for inspection of the designated inspection area even when the object is deformed.

[0069] [Aspect] Those skilled in the art will understand that the embodiments and their modifications described above are specific examples of the following embodiments.

[0070] (Section 1) The welding inspection apparatus according to the present disclosure is a welding inspection apparatus for inspecting a welded part included in an object, and comprises: a first irradiation device that irradiates a transmitting laser beam onto a transmitting point on the upper surface of the object; a detection device that detects ultrasonic waves generated at the transmitting point by the irradiation of the transmitting laser beam and reaching a receiving point on the upper surface of the object; and a control device that extracts reflected waves reflected from the lower surface of the object from among the ultrasonic waves detected by the detection device and determines whether or not there are internal defects inside the welded part based on the extracted reflected waves. The control device acquires position information of a designated receiving point, which is a predetermined receiving point, and position information of a designated inspection area, which is a predetermined inspection area inside the welded part, as well as information on the plate thickness and shape of the object, and uses the acquired information to calculate a transmission range, which is the range of transmitting points that generate reflected waves that pass through the designated inspection area and reach the designated receiving point, and sets the transmitting points within the calculated transmission range.

[0071] According to the welding inspection device described in paragraph 1, the transmission range, which is the range of transmission points that generate reflected waves that pass through the designated inspection area and reach the designated receiving point, is calculated, and the transmission points are set within the calculated transmission range. This makes it possible to set the transmission points at appropriate locations necessary for inspecting the designated inspection area.

[0072] (Article 2) In the welding inspection apparatus described in Article 1, the control device calculates the possible paths that the reflected wave can take to reach the designated receiving point through the designated inspection area, and calculates the transmission range based on the intersection of the calculated possible paths of the reflected wave and the upper surface of the object.

[0073] According to the welding inspection device described in paragraph 2, the possible paths that reflected waves can take to reach a designated receiving point after passing through a designated inspection area can be calculated, and the transmission range necessary for inspection can be appropriately calculated.

[0074] (Section 3) In the welding inspection apparatus described in Section 1, the weld extends in a predetermined direction. The first irradiation device irradiates a plurality of transmission points, which are arranged at predetermined intervals in the scanning direction of the transmission laser beam, by scanning the transmission laser beam along a cross section intersecting the extending direction of the weld. The control device controls the first irradiation device so that the plurality of transmission points fall within the transmission range.

[0075] According to the welding inspection device described in paragraph 3, multiple transmission points can be set so as to fall within an appropriate range necessary for inspection.

[0076] (Article 4) In the welding inspection apparatus described in Article 3, the control device reduces the number of transmission points as the transmission range narrows.

[0077] According to the welding inspection device described in paragraph 4, the number of transmission points is reduced as the transmission range narrows. This allows for proper inspection of the designated inspection area while reducing the number of transmission points as the transmission range narrows, thereby shortening the inspection time.

[0078] (Article 5) In the welding inspection apparatus described in Article 3, the control device increases the density of multiple transmission points as the transmission range narrows.

[0079] According to the welding inspection device described in Section 5, the density of multiple transmission points increases as the transmission range narrows. This allows for improved inspection accuracy (resolution) as the transmission range narrows, without increasing the inspection time.

[0080] (Item 6) In the welding inspection apparatus described in Item 3, the control device increases the number of inspections of the same cross-section as the transmission range narrows.

[0081] According to the welding inspection device in Section 6, the narrower the transmission range, the more inspections are performed on the same cross-section. This allows for proper noise reduction during inspection of a single cross-section without prolonging the inspection time for that section, as the transmission range becomes narrower.

[0082] (Clause 7) In the welding inspection apparatus described in paragraph 1, if deformation of the object is confirmed from the measurement results of the object's shape by the measuring device, the control device calculates the position of the designated receiving point and the position of the designated inspection area after the object has been deformed using the measurement results of the object's shape, recalculates the transmission range using the calculated position of the designated receiving point and the position of the designated inspection area, and sets the transmission point in the recalculated transmission range.

[0083] According to the welding inspection device described in paragraph 7, even if the object is deformed, the transmission point can be set to an appropriate location necessary for inspecting the designated inspection area.

[0084] (Section 8) The welding inspection apparatus according to the present disclosure is a welding inspection apparatus for inspecting a welded part included in an object, comprising: a first irradiation device that irradiates a transmitting laser beam onto a transmitting point on the upper surface of the object; a detection device that detects ultrasonic waves generated at the transmitting point by the irradiation of the transmitting laser beam and reaching a receiving point on the upper surface of the object; and a control device that extracts reflected waves reflected from the lower surface of the object from among the ultrasonic waves detected by the detection device and determines whether or not there are internal defects inside the welded part based on the extracted reflected waves. The control device acquires position information of a designated transmitting point, which is a pre-specified transmitting point, and position information of a designated inspection area, which is a pre-specified inspection area inside the welded part, as well as information on the plate thickness and shape of the object, and uses the acquired information to calculate a receiving range, which is the range of receiving points reached by reflected waves generated at the designated transmitting point and passing through the designated inspection area, and sets a receiving point in the calculated receiving range.

[0085] According to the welding inspection device described in paragraph 8, the receiving range, which is the range of receiving points reached by reflected waves generated at a designated transmission point and passing through a designated inspection area, is calculated, and receiving points are set within the calculated receiving range. This makes it possible to set receiving points at appropriate locations necessary for inspecting the designated inspection area.

[0086] (Section 9) In a welding inspection apparatus described in any of Sections 1 to 8, the detection apparatus includes a second irradiation device that irradiates a receiving laser beam to a receiving point for detecting reflected waves.

[0087] According to the welding inspection apparatus described in paragraph 9, by irradiating the receiving point with a receiving laser beam, the reflected wave reaching the receiving point can be detected.

[0088] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The technical scope provided herein is defined by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0089] 1 Welding inspection device, 2,4 Base material, 5 Bottom surface, 6 Weld bead, 10 Transmitting laser source, 12 Transmitting laser beam irradiation device, 14 Transmitting laser beam, 16 Receiving laser source, 18 Receiving laser beam probe, 20 Receiving laser beam, 22 Control device, 24 Display device, 32 Transmitting point, 36 Receiving point, 36R Designated receiving point, 40 Internal defect, 50R Designated inspection area.

Claims

1. A welding inspection device for inspecting welded parts included in an object, A first irradiation device that irradiates a transmission laser beam onto a transmission point located on the upper surface of the object, A detection device for detecting ultrasonic waves generated at the transmission point by irradiation with the aforementioned transmitting laser light and reaching a receiving point on the upper surface of the object, The device includes a control device that extracts reflected waves from the lower surface of the object from the ultrasonic waves detected by the detection device, and determines whether or not there are internal defects inside the welded part based on the extracted reflected waves. The control device is The location information of the designated receiving point, which is a pre-specified receiving point, the location information of the designated inspection area, which is a pre-specified inspection area inside the welded part, and the plate thickness and shape information of the object are acquired. Using the acquired information, the transmission range is calculated, which is the range of transmission points that generate reflected waves that pass through the designated inspection area and reach the designated receiving point. A welding inspection device that sets the transmission point within the calculated transmission range.

2. The control device is The possible paths that the reflected wave can take to reach the designated receiving point after passing through the designated inspection area are calculated. The welding inspection apparatus according to claim 1, wherein the transmission range is calculated based on the intersection of the possible paths that the calculated reflected waves can take and the upper surface of the object.

3. The welded portion extends in a predetermined direction, The first irradiation device irradiates a plurality of transmission points, which are arranged at predetermined intervals in the scanning direction of the transmission laser beam, by scanning the transmission laser beam along a cross section intersecting the extending direction of the welded portion. The welding inspection apparatus according to claim 1, wherein the control device controls the first irradiation device so that the plurality of transmission points fall within the transmission range.

4. The welding inspection apparatus according to claim 3, wherein the control device reduces the number of transmission points as the transmission range becomes narrower.

5. The welding inspection apparatus according to claim 3, wherein the control device increases the density of the plurality of transmission points as the transmission range becomes narrower.

6. The welding inspection apparatus according to claim 3, wherein the control device increases the number of inspections of the same cross-section as the transmission range narrows.

7. If deformation of the object is confirmed from the measurement results of the object's shape by the measuring device, the control device will Using the measurement results of the shape of the object, the position of the designated receiving point and the position of the designated inspection area after the object has been deformed are calculated, and the transmission range is recalculated using the calculated positions of the designated receiving point and the designated inspection area. The welding inspection apparatus according to claim 1, wherein the transmission point is set in the recalculated transmission range.

8. A welding inspection device for inspecting welds contained in an object, A first irradiation device that irradiates a transmission laser beam onto a transmission point located on the upper surface of the object, A detection device for detecting ultrasonic waves generated at the transmission point by irradiation with the aforementioned transmitting laser light and reaching a receiving point on the upper surface of the object, The device includes a control device that extracts reflected waves from the lower surface of the object from the ultrasonic waves detected by the detection device, and determines whether or not there are internal defects inside the welded part based on the extracted reflected waves. The control device is The system acquires location information of a designated transmission point, which is a pre-specified transmission point, location information of a designated inspection area, which is a pre-specified inspection area inside the welded part, and information on the plate thickness and shape of the object. Using the acquired information, the reception range is calculated, which is the range of reception points to which reflected waves generated at the designated transmission point and passing through the designated inspection area reach. A welding inspection device that sets the receiving point within the calculated receiving range.

9. The welding inspection apparatus according to any one of claims 1 to 8, wherein the detection device includes a second irradiation device that irradiates the receiving point with receiving laser light for detecting the reflected wave.

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