JPS6252456A - Ultrasonic flaw detection apparatus - Google Patents

Abstract

PURPOSE:To make it possible to perform the flaw detection of a moving continuous article to be inspected or a long article having rigidity by a minimum amount of flowing water with good approachability, by setting one set of opposed probes to a local water immersion system and setting one of the probes to a focal system while setting the other one to a non-focal system. CONSTITUTION:A probe holding case C holds probes T1, T2 through a water- tight O-ring R and a pump P supplies water W as a contact medium. At this time, a focal type local water immersion probe T1 is set so as to be directed downwardly in the upper side and the non-focal type local water immersion probe T2 is set so as to be directed upwardly in the lower side and both probes are used in combination. When pulse voltage is applied to the local water immersion probe connected to the transmitting side of an ultrasonic flaw detection apparatus, an ultrasonic pulse is generated to be projected to an article S to be inspected having a nugget N formed thereto through a water column and the ultrasonic pulse passed through the article S to be inspected reaches the receiving side probe and, if this ultrasonic pulse is displayed on an oscilloscope, the wave form corresponding to the state of the article to be inspected can be observed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transmission type ultrasonic flaw detection device that uses a set of local water immersion probes.

[Conventional technology]

Usually, in a transmission type ultrasonic flaw detection device, as shown in FIG. 2 or FIG.
Alternatively, a water immersion type is used, and the probes T+ and T2 are opposed to the object S with water W interposed therebetween. Note that N indicates a nugget formed in the welded portion of the test object S, and F indicates a flaw in the test object S.

In addition, an example of the local water immersion method using a water jet is given in the Japan Society for the Promotion of Science, Steelmaking 19th Committee, Ultrasonic Flaw Detection Method (Nikkan Kogyo Shimbun, revised new edition, July 30, 1949), p. 239.
As shown in Figure 4.111, the conventional local water immersion probe, due to its structure, is usually used in reflection type ultrasonic flaw detection equipment, and is a transmission type, especially when the test object is continuous. It does not apply to moving methods.

[Problem that the invention seeks to solve]

However, in such conventional methods, contact of the probe with a continuous moving object or a rigid long object,
Application was difficult due to the mechanism of wear and submergence.

Further, the method using a jet water stream is not necessarily suitable for specimens with large cross sections, considering the complexity of the apparatus, the amount of water used, the treatment of waste water, etc.

[Means for solving problems]

This invention was made by paying attention to such conventional problems, and by using a local water immersion type for a pair of opposing probes, one of which is a focused type and the other is a non-focused type, Transmission-type ultrasonic flaw detection of easily moving continuous objects and rigid long objects through a water column becomes possible.

[Effect]

When a pulse voltage is applied to the local water immersion probe connected to the transmitting side of the ultrasonic flaw detection device, ultrasonic pulses are generated and projected onto the test object through the water column, and transmitted through the test object. When the ultrasonic pulse reaches the receiving probe and is displayed on an oscilloscope, a waveform corresponding to the state of the object to be inspected can be observed.

If there are scratches on the object to be inspected or gaps between sheets other than the welded portions of overlapping spot welding of thin sheets, part or all of the ultrasonic pulses are blocked and the signal does not reach the receiving probe.

In other words, in the local water immersion method, the water column formed in front of the transducer of the probe communicates with the object to be examined, forming a path for the ultrasonic pulse, but with the focal type local water immersion probe, By adopting this method, the diameter of the ultrasonic beam in the water column is narrowed, and therefore the water column can also be narrowed down, and the amount of water required as a couplant can be significantly reduced.

In the case of a non-focal type, the beam diameter is approximately the same as the transducer diameter in the near-field sound field, and the water column diameter cannot be narrowed down like in the case of a focus type, but it is possible to use a non-focal type local water immersion probe. If the probe is used facing upward, the minimum amount of water that can maintain a water column of the required diameter between the tip of the probe and the object to be sandwiched is extremely small.

Therefore, in a transmission flaw detection system using a localized water immersion probe, the focusing probe faces downward and the non-focusing probe faces upward, and the probes are placed so that the axes of the ultrasonic beams match. By setting , ultrasonic flaw detection with good accessibility is possible with minimal running water.

〔Example〕

The present invention will be explained below based on the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.

First of all, to explain the configuration, UT is an ultrasonic flaw detector → Gakushuhanmegaku, T is a focused local water immersion probe, T2 is a non-focused local water immersion probe, and P is water as a couplant. A pump that supplies W, WT is a water tank, S is the test object in which nugget N is formed, C is a pump that holds the probes T, T, through a watertight O-ring R, and water W is supplied from the pump P. This is the supplied probe holding case. An example of the characteristics of the focusing probe T1 is that the focal length is 1 inch or 2 inches, the sound beam diameter at the focal length is the transducer diameter of 0.125 inches, and the frequency is 2.
In the case of 0MHz, it is said to be approximately 0.9 mm or 1.7 mm/dollar. In addition, in the non-focusing type probe T2, the diameter of the sound flux is approximately the same as the diameter of the transducer in the near-field sound field, so in this example, when the diameter of the transducer is 0.125 inches,
The diameter of the sound bundle is approximately 3.2 mm.

Therefore, the focused local water immersion transducer T is placed upward and downward,
If the non-focusing local water immersion probe T2 is used in combination downward and upward, the probes T1 and T2 have an outer diameter of about 6 to 8 mm at the tip, which provides excellent access to the object S. In addition, a transmission type flaw detection device with the minimum amount of water required can be obtained.

In addition, which of the two probes T, T2 should be used as the transmitting side or the receiving side can be selected as appropriate depending on the characteristics of the object S, but if there are no particular restrictions, the focusing type probe Condition setting is easier if T1 is on the transmitting side.

Note that if the downward, upward-facing probe T2 has an angle of more than a certain degree with respect to the vertical line, the required water flow rate will inevitably increase, depending on the distance between the probe and the test object. For example, if the probes are placed in a nearly horizontal position due to the limitations of the object to be inspected,
There may be cases where it is necessary to use both confocal probes. However, the sound axis adjustment of a focusing type probe requires extreme precision, and it is nearly impossible to match the sound axes of two probes, including the distance and angle to the test object. The reproducibility when resetting in response to a change in the test object is extremely poor, and a four-dimensional fine adjustment device that also includes angle is required, which significantly impairs functionality.

The actual setting procedure is to first set the focusing probe TI to the test object S at a predetermined distance and at a predetermined angle (usually at a right angle), and then set the non-focusing probe T2. However, in the case of a non-focus type, the tolerance of the reception range is large, so
The intervals and angles do not need to be as precise as in the focal type.

Regarding the upper local water immersion probe T, it must be confirmed that there are no residual bubbles in the water column in front of the vibrator prior to measurement.

〔Effect of the invention〕

As explained above, according to the present invention, the configuration is a combination of a focused type probe and a non-focused type probe. The hopeless difficulty of aligning both sound axes completely and maintaining the surface angle with the surface of the object to be sandwiched when performing type flaw detection etc. is avoided.

(mouth) By using one local water immersion probe as a focusing type,
The tip aperture of the probe holding case can be narrowed down to a value close to the sound flux diameter, which eliminates the possibility of bubbles remaining in the water column in front of the transducer while keeping the flow rate low, and makes it easy to treat wastewater. becomes.

c) On the other hand, by making the lower local water immersion probe non-focusing, the tip aperture of the probe holding case becomes somewhat larger, but because the opening faces upward, air bubbles may form even if the water flow rate is reduced. It is possible to maintain a continuous water column with the test object without worrying about residue.

2) After the focusing probe has been properly centered on the object, the focusing of the non-focusing probe does not require much precision.

Significant effects such as these can be obtained.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an embodiment of the present invention, Fig. 2 is an explanatory diagram of a conventional probe with a delay material brought into contact with a test object via glycerin, and Fig. 3 is a diagram showing a conventional probe with a delay material. A probe with a test object positioned between a pair of probes underwater, T2 is a receiving probe, R is a watertight O-ring, C is a probe holding case, P is a pump, and WT is a A water tank, S indicates a test object, N indicates a nugget of a spot weld, F indicates a flaw, W indicates water, and G indicates glycerin. Agent Patent Attorney Jun Miyazono - Figure 1 T

Claims (3)

[Claims] (1) In a transmission-type ultrasonic flaw detection device that uses a local water immersion probe to inspect flaws, etc. on a test object using a transmitted waveform obtained by projecting ultrasonic pulses perpendicularly onto the test object, one set of An ultrasonic flaw detection device characterized in that one of the local water immersion probes is a focusing type and the other is a non-focusing type. (2) The ultrasonic flaw detection apparatus according to claim 1, wherein the focusing probe is on the transmitting side and the non-focusing probe is on the receiving side. (3) When the probe is set in the vertical direction, the focusing probe is arranged above and the non-focusing probe is arranged below. Ultrasonic flaw detection equipment.