JP3564683B2 - Weld monitoring method - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION
[0001]
According to the present invention, even during welding work, the occurrence of defects and defects is detected by ultrasonic flaw detection for each welding pass, so that welding conditions can be corrected and welding repairs can be quickly performed before moving to the next welding pass. It concerns monitoring methods.
[0002]
[Prior art]
As is well known, the ultrasonic flaw detection test transmits an ultrasonic pulse from the surface of a welded portion, which is a test sample, to the inside, detects an ultrasonic echo reflected by a defect in the test sample, and detects the echo. This method is known as a method of estimating the size of a defect from its size, measuring the time from returning the ultrasonic wave to returning, and knowing the distance to the defect position, and widely used.
[0003]
Here, a conventional ultrasonic inspection method for a welded portion will be described. Generally, as the ultrasonic flaw detection method for the welded portion, a method that is performed for each welding pass, which is an intermediate stage during the welding operation, and a method that is performed after all the welding operations are completed, are considered. First, a case where ultrasonic flaw detection is performed for each welding pass by a conventional ultrasonic flaw detection method will be described with reference to FIG. For example, in the case of flat plate butt joint welding (bevel groove shape V, the number of welding passes is 10), during welding (for example, when several passes of welding are completed), as shown in FIG. Only a part of the groove surface of the weld joint is joined with the weld metal, and a part of the groove remains unwelded and hollow. In such a situation, the conventional ultrasonic flaw detection method, that is, one probe type that transmits and receives an ultrasonic beam with one probe, and performs ultrasonic flaw detection with a normal type, A reflected echo is always detected from the boundary between the surface or the groove and the weld metal, even if no defect exists. FIG. 6B is a flaw detection image of the flaw detection result obtained in FIG. 6A, and the echo displayed as is apparent from this flaw detection image is a reflection echo from a groove or a bead. 6 and 7, reference numerals 9 and 10 denote base materials, R denotes a welded portion, 15 denotes a probe, and c denotes an ultrasonic beam path.
[0004]
On the other hand, if there is a defect inside the welded portion, as shown in FIG. 7A, a reflected echo from a groove or bead shape and an echo from the defect are detected at the same time. When this is formed into a flaw detection image, as shown in FIG. 7B, the reflected echoes of the two overlap, and it is not possible to clearly distinguish the defective echo from other reflected echoes.
[0005]
[Problems to be solved by the invention]
For this reason, in conventional ultrasonic testing, ultrasonic testing was performed after welding was completed, not during welding work, and as a result, for example, a defect was found near the center of the sheet thickness. In such a case, welding must be performed again after excavating the welded part to the position where defects were recognized by gouging etc., and therefore, it takes a lot of time and cost for gouging and repair work. It is.
[0006]
The present invention has been made to solve the disadvantages of the conventional ultrasonic testing method described above, and its purpose is to perform ultrasonic testing for each welding pass during welding even if all welding has not been completed. A welding monitoring method that makes it possible to detect defects and defects even when the above-mentioned defects and defects are detected, so that corrective processing can be performed immediately and subsequent welding work can be performed smoothly. Is to provide.
[0007]
Therefore, a welding monitoring method according to claim 1 is a welding monitoring method for monitoring a welding state of a welded portion during a welding operation, wherein a transmitting probe is provided on a surface of a base material with a groove to be welded interposed therebetween. a probe for receiving and opposed, each weld pass, times at folding waves from the defect that is distinct from the ultrasonic wave from the bead upper and lower ends of the weld, in order to perform the ultrasonic testing of the weld The ultrasonic beam is concentrated on the welding path to be inspected for each welding lamination by narrowing the distance between the pair of transmitting and receiving transducers from the first layer to the upper layer of the welded portion. It is characterized by having been propagated .
[0008]
During the welding operation, when the welding condition of the welded part is detected by a single probe (one type that transmits and receives an ultrasonic beam) method, even if a defect echo is detected, this defect echo and groove And it is not easy to determine the discrimination from the reflected echo from the bead shape. Therefore, it was unavoidable that flaw detection of the weld was performed at the stage when all welding passes were completed.In this case, if a defect was found near the center of the sheet thickness, for example, the weld was dug considerably by gouging or the like. , Welding was done again. Therefore, gouging and repair work required a lot of time and cost. This was an extremely large loss when the objects to be welded were very thick plates. Further, if the flaw detection results in a defect even after performing the welding again, the gouging and welding must be performed again, and the loss was immeasurable. On the other hand, in the present invention, the transmitting probe and the receiving probe are arranged to face each other, and for each welding pass, a defect from a defect that is distinguished from ultrasonic waves from the upper and lower ends of the bead of the welded portion. at diffraction waves, since the ultrasonic flaw detection of the welded portion, without waiting for all of the weld pass is complete, so as to perform the ultrasonic flaw detection immediately welds for each weld pass, the welding path It is possible to detect the presence / absence of a defect or a defect in the above. When a defect occurs, the welding conditions are immediately corrected, and when a defect is detected in the welded portion, feedback control can be performed so that repair welding can be performed immediately. It is expected that extremely reliable welding will be achieved when all welding passes are finally completed. Further, as in the conventional case, when the welding state of the welded portion is detected by a single probe (a type in which one probe transmits and receives an ultrasonic beam) during a welding operation, the flaw detection target is the first of the welded portion. Even if the probe is moved closer to the groove portion from the layer portion to the upper layer portion, it is not easy to distinguish between a defective echo and a reflected echo from the shape of the upper and lower ends of the bead. After all, it is impossible to detect flaws until all welding is completed, and it is extremely inefficient. Therefore, according to the present invention, the distance between the pair of transmitting and receiving probes is made smaller and narrower from the first layer to the upper layer of the welded portion, so that the ultrasonic wave is always applied to the welding path to be inspected for each welding lamination. Since the beam is concentrated and propagated, if the weld is the first layer, regardless of whether it is the upper layer, the echo from the defect can always be detected, and the defect can be detected easily. .
[0009]
A welding monitoring method according to claim 2 is a welding monitoring method for monitoring a welding state of a welded portion during a welding operation, wherein the transmitting probe and a transmitting probe are provided on a base material surface with a groove to be welded interposed therebetween. A probe for reception is arranged oppositely, and with a certain time lag for welding work, the pair of probes arranged above are moved to follow and distinguished from ultrasonic waves from the upper and lower ends of the bead of the welded portion. times in folding wave from defects, and configured to perform ultrasonic inspection of the weld, further from the first layer portion of the welded portion by narrowing reduce the distance of the transmitting and receiving pair of probes according to reach the upper portion This is characterized in that the ultrasonic beam is intensively propagated to the welding path to be inspected for each welding lamination .
[0010]
As described above, in the conventional ultrasonic inspection method, the inspection during the welding operation is difficult as a result, and the inspection cannot be substantially performed until all the welding operations are completed. In addition, if a defect is found as a result of the flaw detection after the welding operation is completed, the part where the defect is present is excavated by gouging, etc., and re-welding is performed. Cannot be denied, and flaw detection after re-welding is indispensable, and there is a possibility that a great deal of time and effort is required from the start of welding to the end of flaw detection. On the other hand, according to the present invention, the transmitting probe and the receiving probe are disposed to face each other, and the pair of the probes disposed opposite each other follows the welding operation with a certain time lag. so moved, rotating in folding wave from the defect that is distinct from the ultrasonic wave from the bead upper and lower ends of the weld, since the ultrasonic flaw detection of the welded portion, the middle, there is detection of the occurrence of problems or defects In such cases, repair welding is performed immediately, and welding conditions are modified as necessary. Further, after the welding conditions are corrected or repair welding is performed, the ultrasonic inspection follows the welding operation restarted, so that the inspection operation is completed with the above-mentioned fixed time lag from the completion of the welding operation. Therefore, it is possible to obtain a very efficient welding and automatic flaw detection system by adding a system for automatically following the ultrasonic flaw detection in the welding operation. Further, as in the conventional case, when the welding state of the welded portion is detected by a single probe (a type in which one probe transmits and receives an ultrasonic beam) during a welding operation, the flaw detection target is the first of the welded portion. Even if the probe is moved closer to the groove portion from the layer portion to the upper layer portion, it is not easy to distinguish between a defective echo and a reflected echo from the shape of the upper and lower ends of the bead. After all, it is impossible to detect flaws until all welding is completed, and it is extremely inefficient. Therefore, according to the present invention, the distance between the pair of transmitting and receiving probes is made smaller and narrower from the first layer to the upper layer of the welded portion, so that the ultrasonic wave is always applied to the welding path to be inspected for each welding lamination. Since the beam is concentrated and propagated, if the weld is the first layer, regardless of whether it is the upper layer, the echo from the defect can always be detected, and the defect can be detected easily. .
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, specific embodiments of the welding monitoring method of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram for explaining a procedure of a welding monitoring method according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram for explaining a welding monitoring method when no defect is detected. FIG. 3 is an explanatory diagram for explaining a welding monitoring method when a defect is detected, FIG. 4 is an explanatory diagram for explaining narrowing of a monitoring range in the welding monitoring method, and FIG. It is a schematic diagram of the apparatus used.
First, referring to FIG. 1, a welding monitoring method according to an embodiment of the present invention will be described with reference to a case of flat plate butt joint welding as an example. First, a pair of transmitting and receiving probes are arranged opposite to each other on the surface of a base material with a groove to be welded interposed therebetween, and a welding portion (indicated by reference numeral 1 in FIG. 1) from one of the probes is being welded. An ultrasonic beam is emitted for each pass), and the other probe receives the reflected wave to detect a flaw (indicated by reference numeral 2 in FIG. 1). Next, the flaw detection data obtained above is converted into image data to obtain a flaw detection image (indicated by reference numeral 3 in FIG. 1). As a result of the data analysis of the flaw detection image (indicated by reference numeral 4 in FIG. 1), if a defect is found in the welded portion, the welding conditions for correcting the defect are immediately processed, and the welding conditions are corrected. Feedback control is performed to a welding device or the like during the welding operation (indicated by reference numeral 5 in FIG. 1). On the other hand, when occurrence of a defect is recognized, welding and flaw detection are interrupted for a while, and repair welding is performed (indicated by reference numeral 6 in FIG. 1).
[0015]
In addition to the method of detecting a flaw for each welding pass, for example, the ultrasonic flaw detection may be followed with a certain time lag with respect to the welding work. Even if the welding conditions are corrected or repair welding is performed, the ultrasonic inspection follows the restarted welding operation, so that the flaw detection operation is terminated with the above-mentioned fixed time lag from the completion of the welding operation. Therefore, extremely efficient welding and flaw detection work can be performed by adding a system for automatically following ultrasonic flaw detection to welding work.
[0016]
By the way, as the flaw detector used in the above welding monitoring method, for example, an apparatus as shown in FIG. 5 can be considered. That is, assuming application to butt flat welding, a pair of transmitting and receiving probes 7 and 8 are basically arranged on the surfaces of the base materials 9 and 10 so as to face each other with the groove 11 therebetween. The children 7, 8 are slidable on two rails. Reference numeral 12 denotes a display which can process flaw detection data from the probes 7 and 8 and display the flaw detection data in the form of image data. Reference numeral 13 denotes a welding machine. It is needless to say that the flaw detector used in the welding monitoring method of the present invention is not limited to the above one, but it is preferable that the probes 7, 8 automatically follow the welding machine 13 with a certain time tag. Type as you can. The constant time lag means that the probes 7 and 8 follow the inspection for a flaw detection, for example, with a delay of 300 mm from the welded portion.
[0017]
Next, an ultrasonic flaw detection method used in the welding monitoring method will be described with reference to FIGS. FIG. 2 shows flaw detection in the case where there is no defect in the welded portion. As shown in FIG. 2A, during the welding operation, the surface of the base material 9, 10 is sandwiched by the groove 11 to be welded. The automatic ultrasonic flaw detection is performed for each welding pass by a pair of transmitting and receiving probes 7 and 8 disposed opposite to each other. In this case, the ultrasonic beams a and b emitted from one probe 7 wrap around or reflect at the upper and lower ends of the bead of the welded portion R, and the other probe 8 receives the reflected waves. It has become. The results of the flaw detection at this time are all displayed by the display device, and if no defect exists, only ultrasonic waves from the upper and lower ends of the bead are detected. That is, as shown in FIG. 2B, the ultrasonic beam a from the transmission probe 7 wraps around the upper end of the welded portion, and the ultrasonic beam b is reflected at the lower end of the welded portion and received. And the flaw detection result is displayed on the display device.
[0018]
On the other hand, FIG. 3 shows a flaw detection in the case where a defect is present in the welded portion, that is, in FIG. 3A, the ultrasonic beam a from the transmitting probe 7 is at the upper end of the welded portion, and The ultrasonic beam b is reflected at the lower end of the welded portion, and the ultrasonic beam reflected on the defect is also reflected and simultaneously received by the receiving probe 8. The results of this flaw detection are as shown in FIG. 4B, and in addition to the ultrasonic waves from the upper and lower ends of the bead, diffracted waves from the upper and lower ends of the defect are displayed at a portion corresponding to the welded portion. As described above, the diffracted wave due to the defect is clearly distinguished from the ultrasonic waves at the upper and lower ends of the bead, and it is extremely easy and easy to confirm the existence of the defect.
[0019]
Further, a method of narrowing down the monitoring method will be described with reference to FIG. That is, as shown in FIG. 7A, flaw detection is performed on the first layer portion R1. Next, when flaw detection is performed on the second layer, as shown in FIG. 4B, the distance between the probes is shortened somewhat, and the ultrasonic beam concentrates and propagates on the welding path to be inspected. To do. Then, in the third layer flaw detection, as shown in FIG. 3C, the distance between the probes is further reduced to make the ultrasonic beam converge and propagate. By performing monitoring by focusing on the target laminated portion in this way, the defect detection performance is improved, and the analysis processing time of the flaw detection result can be shortened.
[0020]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be implemented with various modifications without impairing the gist of the present invention. By applying it to thick joints such as welded joints such as small girder bridges and pressure vessels, the repair work process can be shortened.
[0021]
【The invention's effect】
As described above, according to the welding monitoring method of the first aspect, the transmission probe and the reception probe are used to immediately wait for each welding pass without waiting for completion of all welding passes. Since the ultrasonic inspection of the welded portion is performed, it is possible to detect the occurrence of a defect or a defect in each welding pass. Then, when the occurrence of a defect in the weld is detected, repair welding is immediately performed, and feedback control can be performed so as to correct the welding conditions as necessary, so that repair welding can be performed for each welding pass, and so on. Finally, when all welding passes are completed, reliable welding can be confirmed. In addition, by narrowing the interval between the pair of transmitting and receiving probes as the distance from the first layer to the upper layer of the weld decreases, the ultrasonic beam always concentrates on the welding path to be inspected for each welding lamination. Therefore, the defect and the ultrasonic wave at the upper and lower ends of the bead can be easily distinguished from each other regardless of whether it is the first layer portion or the upper layer portion.
[0022]
According to the welding monitoring method of the second aspect, the ultrasonic probe is used to follow the welding operation with a certain time lag with respect to the welding operation by using the transmitting probe and the receiving probe. If a defect is detected or a defect is detected on the way, repair welding is immediately performed, and welding conditions are corrected as necessary. Further, after the welding conditions are corrected and repair welding is performed, the ultrasonic inspection follows the welding operation restarted, so that the inspection operation is completed with the above-mentioned fixed time lag from the completion of the welding operation. Therefore, it is possible to obtain a very efficient welding and automatic flaw detection system by adding a system for automatically following the ultrasonic flaw detection in the welding operation. In addition, by narrowing the distance between the pair of transmitting and receiving probes from the initial layer to the upper layer of the welded portion, the ultrasonic beam is always concentrated on the welding path to be inspected for each welding lamination. Therefore, the defect and the ultrasonic wave at the upper and lower ends of the bead can be easily distinguished from each other regardless of whether it is the first layer portion or the upper layer portion.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a procedure of a welding monitoring method according to an embodiment of the present invention; FIG. 2 is an explanatory diagram illustrating a welding monitoring method according to an embodiment of the present invention; Shows a case where no defect is detected.
FIG. 3 is an explanatory diagram for explaining a welding monitoring method according to an embodiment of the present invention, showing a case where a defect is detected.
FIG. 4 is an explanatory diagram for explaining narrowing of a monitoring range in the welding monitoring method according to the embodiment of the present invention; This shows the case where no defect is detected.
FIG. 5 is a schematic view of an apparatus used for a welding monitoring method according to an embodiment of the present invention.
FIG. 6 is an explanatory diagram for explaining a conventional welding monitoring method, and shows a case where no defect is detected.
FIG. 7 is an explanatory diagram for explaining a conventional welding monitoring method, and shows a case where a defect is detected.
[Explanation of symbols]
Reference Signs List 1 welding 2 flaw detection 3 flaw detection image 4 data analysis 5 correction of welding conditions 6 repair welding 7 transmitting probe 8 receiving probe 9, 10 base material 11 groove 12 display 13 welding machine R welding part R1 First layer part R2 Two layer part R3 Three layer part

Claims (2)

A welding monitoring method for monitoring a welding state of a welding portion during a welding operation, in which a transmitting probe and a receiving probe are arranged opposite to each other on a surface of a base material with a groove to be welded interposed therebetween. and, for each weld pass, times at folding waves from the defect that is distinct from the ultrasonic wave from the bead upper and lower ends of the welded portion, and configured to perform ultrasonic inspection of the weld, the first layer portion of the further weld The ultrasonic beam is concentrated and propagates to the welding path to be inspected for each welding lamination by narrowing the interval between the pair of transmitting and receiving probes to the upper layer from the point of view. And welding monitoring method. A welding monitoring method for monitoring a welding state of a welding portion during a welding operation, in which a transmitting probe and a receiving probe are arranged opposite to each other on a surface of a base material with a groove to be welded interposed therebetween. and, with a certain time lag relative to the welding operation is moved to follow the pair of probes described above opposed at diffraction waves from the defect that is distinct from the ultrasonic wave from the bead upper and lower ends of the weld , Configured to perform ultrasonic flaw detection of the welded portion, and further narrowing the interval between the pair of transmitting and receiving probes to reach the upper layer portion from the first layer portion of the welded portion, thereby making the inspection target for each welding lamination. A welding monitoring method, wherein an ultrasonic beam is intensively propagated to a welding path to be welded.

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