JPS6228662A - Welding flaw detecting method - Google Patents

Abstract

PURPOSE:To continuously detect a welding defect while under welding by interlocking an electromagnetic ultrasonic surface probe from the rear part of a welding torch. CONSTITUTION:The probe 6 for transmitting the surface wave of an electromagnetic ultrasonicwave and probe 7 for receiving are set to an integrated type casing 8 at the position of a welding solidified metal 3 at rear part of the welding torch 2 advancing in welding direction and moved smoothly together with the torch on the body 1 to be inspected. Consequently the welding defect inn the welding metal can be detected at real time, by the electromagnetic ultrasonic probe being interlocked with the welding torch and by using the surface wave further the defect on the surface layer of the welding metal can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flaw detection method for in-process detection of defects opened in the surface of a weld metal during welding and defects in the surface layer of the weld metal.

[Conventional technology]

Conventionally, ultrasonic flaw detection of welded parts has been carried out after welding is completed or at an intermediate stage, and until now there has been no example of flaw detection performed in real time during welding. Furthermore, in conventional ultrasonic flaw detection, it is necessary to place the specimen and the probe in close contact with each other via a couplant, and the defect detection performance is greatly affected by the surface shape of the specimen.

[Problem that the invention seeks to solve]

Conventionally, it is not possible to inspect welds in real time, so in multi-layer welding, etc., defects inherent in the weld metal cannot be detected at the time they occur. This process required a great deal of expense and time, and was also a cause of quality deterioration.

Furthermore, defect detection using conventional ultrasonic probes requires a couplant between the probe and the test object.

Even if an attempt is made to perform real-time inspection by linking a sheet metal welding torch and a probe, it is difficult to maintain constant contact with the probe, and the detection ability is easily affected by the surface conditions of the object to be inspected. Accurate defect detection is difficult.

[Failure to solve the problem]

In view of the above-mentioned circumstances, the present invention provides a welding flaw detection method characterized by interlocking an electromagnetic ultrasonic surface wave probe from behind a welding torch to continuously detect welding defects occurring near the surface layer of weld metal during welding. To offer a tiger.

[Effect]

According to the present invention, welding defects in weld metal can be detected in real time by an electromagnetic ultrasonic probe linked to a welding torch, and defects in the surface layer of weld metal can be detected by using surface waves.

〔Example〕

An example of the method of the present invention will be explained with reference to the drawings.

1A and 1B, an electromagnetic ultrasonic surface wave transmitting probe 6 is placed at the position of the welding solidified metal 3 behind the welding torch 2 which is proceeding in the welding method shown by the arrow in the groove l' of the specimen 1. ．．
A receiving probe 7 is set in a conductive casing 8, and is connected to the welding torch 2 via a connecting means 5, keeping the relative distance to the torch 2 constant, and moving over the object 1 using a bearing 16 installed in the casing 8. Move smoothly with the torch.

The transmitting device 9 sends a pulsed high-frequency current to the transmitting probe 6.
The ultrasonic waves generated within the object 1 are reflected by the defect 4, converted into voltage by the receiving probe 7, and amplified by the amplifier 10.

Only the necessary frequency components are extracted in the filter 11 and sent to the signal processing system 12. Further, the threshold value storage system 13 determined based on the signal from the healthy part and the detection signal are compared and discriminated by the comparison discrimination system 14, and the defect location is stored and displayed in the defect location storage system 15.

Figure 2 shows a sampling experiment of the waveforms of welding surface defects and sound areas during MAG welding using the configuration shown in Figure 1.
Flaws were detected at a welding speed of 20 an/min and an electromagnetic ultrasonic surface wave probe at 9 frequencies of 500 kHz. The defect to be detected at this time was a 1 mm* cylindrical defect on the surface layer of the weld metal. As is clear from Fig. 2, the defect signal can be clearly determined, making it possible to detect flaws during welding in-process.

〔Effect of the invention〕

The present invention achieves the following effects with the above configuration.

Suitable for in-process inspection for welding.

(1) The welded part can be detected without contact with the test object.

It is now possible to detect defects while moving the probe during welding.

(2) By using surface waves in ultrasonic mode, it became possible to detect defects existing in the surface layer of weld metal.

[Brief explanation of drawings]

FIG. 1A is a plan view of one embodiment of the method of the present invention. FIG. 1B is a front view of the same as above, and FIG. 2 is an explanatory diagram of an embodiment of the method of the present invention. -2...Welding torch,
4'...Bevel, 3...Weld metal. 4... Welding defect, 5... Welding torch/probe connection part. 6... Transmission probe, 7... Receiving probe, 8...
・Casing, 9... Transmitting device, 10... Amplifier,
11... Part of filter, 12... Signal processing system, 13
...Threshold value memory system, 14...Comparison system, 15...Fault position memory system, 162゛Rakuten Hina 3: Axis A4;, Cliff Poster Kem 5:1 + Raccoon Ugly Streaming IF5 prisoner

Claims (1)

[Claims] A welding flaw detection method characterized by interlocking an electromagnetic ultrasonic surface wave probe from the rear of a welding torch to continuously detect welding defects occurring near the surface layer of weld metal during welding.