JPS62148853A - Ultrasonic flaw detecting method for welded zone - Google Patents

Abstract

PURPOSE:To perform flaw detection securely even at the part of a fin by allowing two of probes arranged opposite each other across the fin and a welded zone to receive an ultrasonic wave which is transmitted by another probe and reflected by the defect of the welded zone, and transmitting and receiving ultrasonic waves continuously in sequence. CONSTITUTION:When the flaw at the part of the fin 3 of the butt welded zone of a finned tube 10 is detected with an ultrasonic wave, four-channel counter type oblique probes 4-7 are arranged facing each other across the fin 3 and welded zone 2. Then, the flaw detection is carried out continuously according to ultrasonic transmission order and operation time set by a channel selector 8. When the ultrasonic wave is transmitted by the probe 4 to the weld zone 2, the transmitted ultrasonic wave is reflected and received by the probes 5 and 6, and the probes 5, 6 and 7 transmit ultrasonic waves to perform a series of operations continuously. Thus, it is known whether or not the weld zone 2 has a defect.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic flaw detection method used for flaw detection of butt welds of fin tubes used in land boilers.

[Prior art] For example, fin tubes are used to manufacture monowall panels for boilers, and the butt welds of the fin tubes can be inspected by emitting gamma rays or X-rays from outside the tube to weld. This was done using a radiographic method that took pictures of a film wrapped around the body. Furthermore, conventionally, an ultrasonic flaw detection method has been adopted as a substitute for the above-mentioned radiographic inspection method. In this ultrasonic flaw detection method, as shown in Fig. 5, a probe is placed on the outer surface of a welded tube a toward the axial direction of the tube a, and the probe is attached to the welded part C. The probe moves around the tube a while detecting the presence or absence of defects by emitting ultrasonic waves and receiving the reflected ultrasonic waves with the probe.

[Problems to be Solved by the Invention] However, with the conventional radiation inspection method, there are problems such as poor detection of linear defects in welds, risk of Oj1 radiation failure, and high inspection cost. There was a problem.

In addition, in the ultrasonic flaw detection method, the probe is placed on the tube a and detected while moving in the circumferential direction, and when it is applied to the flaw detection of the butt weld C of the fin tube, fin d
For this reason, the probe did not rest on the tube a at the fin d, and therefore it was practically impossible to detect flaws in the weld C in the range A shown in FIG. 6 at the fin d.

Accordingly, the present invention aims to enable reliable flaw detection even in the fin portion in flaw detection of the butt welded portion of the fin elongated tube.

[Means for Solving the Problems] The present invention provides an ultrasonic transmission order of a four-channel opposed angle angle probe in which the fin and the welded part of the butt welded part of the fin elongated tube are sandwiched and placed opposite each other. The operating time is set electronically in time divisions, and an operation is performed in which ultrasonic waves are emitted from any one of the four probes and simultaneously received by the other probes according to the set order. Perform flaw detection continuously.

[Function] Behind the four probes placed between the fin and the welded part, 1
When the ultrasonic waves emitted from one probe are reflected by a defect in the weld, they are received by the other two probes. Next, ultrasonic waves are emitted from another probe, reflected by a defect in the weld, and received by the other two probes. In this way, the welded portion is detected by sequentially and continuously transmitting and receiving ultrasonic waves.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment in which a butt weld 2 of a fin elongated tube 1 is inspected for flaws in a weld 2 in a fin 3 portion.

Four full angle angle probes 4, 5, 6.7 are arranged diagonally opposite each other so as to sandwich the fin 3 and the welded part 2, forming a 4-channel opposing type. Each probe 4, 5, 6.7 is integrally equipped with an ultrasonic transmitter and an ultrasonic receiver so that it can transmit and receive ultrasonic waves. Ultrasonic waves received by probes 5 and 6 and transmitted by probe 5 are received by probes 4 and 7. Similarly, when probe 6 is transmitting, probes 4 and 1 are receiving and transmitting ultrasound waves. When the probe 7 is transmitting, the probes 5 and 6 are made to function as receivers.

Each of the probes 4, 5, 6.7 is connected to a channel selector 8 as shown in FIG. The operating time of
The signals obtained by transmitting and receiving ultrasonic waves in order from 5, 6, and 7 are input to the channel selector 8. Further, the signals sequentially input to the channel selector 8 are output as waveform signals to an ultrasonic probe 10 that can function as a monitor, and are displayed on the ultrasonic flaw detector 10 as a waveform for one scan in the thickness direction. to be done.

When performing ultrasonic flaw detection on the fin 3 portion of the butt weld of the fin elongation tube 10, use the 4-channel opposing angle probe 4 so as to sandwich the fin 3 and the weld 2 and face each other as shown in FIG. ,5
, 6.7 is placed. Next, flaw detection is performed continuously according to the ultrasonic transmission order and operation time set by the channel selector 8. Now, when ultrasonic waves are transmitted from the probe 4 of the 4-channel opposed angle angle probe to the welding part 2 based on the order set in the channel selector 8, the transmitted ultrasonic waves are reflected and detected. The signal is received by probes 5 and 6. Next, after a certain period of time according to the set order, probe 5 transmits ultrasonic waves, which are received by probes 4 and 7, and then probe 6 sequentially transmits ultrasonic waves, which are received by probes 4 and 7. Then, probe 7 emits ultrasonic waves, which are received by probes 5 and 6. A series of operations like this are performed continuously, and when received by each probe 4, 5, 6, 7, it is sent to the ultrasonic flaw detector 1 via the channel selector 8.
0 as a waveform signal and displayed. This allows the presence or absence of defects in the welded portion 2 to be known.

[Effects of the Invention] As described above, according to the welded part flaw detection method of the present invention,
The welded part of the fin part when butt welding the fin extension tube is 4
Continuous flaw detection is performed using a channel-opposed angle probe.
An excellent effect can be achieved in that flaw detection of the welded portion of the fin portion can be easily and accurately performed.

[Brief explanation of drawings]

FIG. 1 is a plan view of a tube schematically showing the state in which the method of the present invention is carried out, FIG. 2 is a side view of the tube, and FIG. 3 is a sectional view of the tube.
Fig. 4 is a control block diagram of the probe used in the present invention, Fig. 5 is a diagram showing an example of the conventional ultrasonic detection method, and Fig. 6 is a diagram showing an example of the conventional ultrasonic detection method. It is a figure showing a range. 1 is fin attached, 2 is welded part, 3 is fin, 4, 5, 6°7
is a probe, 8 is a channel selector, 9 is a probe 1!13 cable, and 10 is an ultrasonic flaw detector. Patent application: Hitoshi Kawajima Harima Heavy Industries Co., Ltd. Patent application: Hitoshi Kawajima Inspection and Measurement Co., Ltd.

Claims (1)

[Claims] 1) The ultrasonic transmission order and operating time of a 4-channel opposed angle angle probe, which is placed with the fins and welds facing each other in the butt weld of a fin tube, are set electronically by time division. , welding characterized in that flaw detection is performed by successively performing an operation of transmitting ultrasonic waves from any one of the four probes and simultaneously receiving them from other probes according to the set order. Ultrasonic flaw detection method.