JPS61137059A - Apparatus for inspecting surface flaw - Google Patents

Abstract

PURPOSE:To allow the titled apparatus to well follow the surface of an object to be inspected, by supporting a tire shaped ultrasonic probe through an air cylinder apparatus and a spring. CONSTITUTION:A surface flaw inspection apparatus has a support 14 relatively moved to the inspection direction of a steel pipe 13 and also has air cylinder apparatus 15 arranged to the support 14. A spring press plate 17 is fixed to the leading end part of the piston rod 16 of the apparatus 15 and a compression spring 18 is interposed between a holder 11 and the press plate 17. The apparatus 15 absorbs low speed vibration having large amplitude and the spring 18 absorbs small amplitude.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J] The present invention relates to a surface flaw inspection device for steel plates, large diameter steel pipes, etc.

[Prior art] Conventionally, for inspection of surface flaws on steel plates, for example,
-f1327fl As shown in Figure 3, a surface flaw inspection device that detects flaws using surface waves having a frequency in the ultrasonic range is used.As shown in Figure 3, surface waves use the law of refraction of sound waves. The ultrasonic wave transmitted by the ultrasonic transducer 1 can be generated on the surface of the steel plate 2 by making it obliquely incident on the steel plate 2 at an incident angle θI with a refraction angle of 90 degrees. The incident angle θi is approximately 30 degrees when the ultrasonic wave is incident on the steel plate 2 from the water 3 as shown in Fig. In flaw detection using surface waves, which are concentrated at a depth of up to 100 mm and can effectively detect surface flaws, surface wave pulses are propagated to the surface of the object, reflected at the surface flaws, Ultrasound 1 as a transmitter/receiver! Detects surface wave pulses that return to the surface, making it possible to detect surface flaws.

By the way, in the inspection of surface flaws on steel plates and large-diameter steel pipes, as shown in FIG. The probe 12 is connected to a large diameter steel pipe 1 via a suitable couplant.
3, surface wave pulses can be transmitted and received, and surface flaws can be detected. Therefore, the tire-shaped ultrasonic probe 12 is fixed using a suitable holding means,
Either the tire-shaped ultrasonic probe 12 is pressed against the large-diameter steel pipe 13 and the large-diameter steel pipe 13 is run, or the tire-shaped ultrasonic probe 12 is mounted on a cart that runs along the large-diameter steel pipe 13. If the cart is run with the tire-shaped ultrasonic probe 12 pressed against the large-diameter steel pipe 13, the large-diameter steel pipe 1
3. It becomes possible to inspect the entire surface.

In inspecting surface flaws using surface waves using the tire-shaped ultrasonic probe 12, it is important to maintain a constant efficiency of transmitting and receiving surface waves to and from the surface of a steel pipe, etc. It is important to make the ultrasonic probe 12 closely follow the movement of the surface of the steel pipe, etc., and to press it against the surface with a constant pressure. Conventionally, a spring or an air cylinder device has been used as a means for causing an ultrasonic probe such as a tire-shaped probe to follow the surface of a subject and press it with a constant pressure.

[Problems to be Solved by the Invention] However, when the spring or air cylinder device described in J. is used in a surface flaw inspection device using a surface wave using a tire-shaped ultrasonic probe, there are the following drawbacks. .

(a) Since the spring cannot take a large stroke, if the curve of the test object is large, it will not be able to follow this bend, in other words, the probe will move away from the test object, or the probe will not move away from the test object. In some cases, the probe may be strongly pinched between the probe and the support of the probe, leading to its destruction.

(b) The air cylinder device has a slow response to the movement of the surface of the subject, and in a system in which the tire-shaped ultrasonic probe is fixed and the subject is moved to inspect the surface, The relatively small amplitude but high-speed vibrations of the specimen that occur during the process also allow a tire-shaped ultrasonic probe to be attached to a trolley that runs along the specimen, and this trolley is driven to inspect the surface for defects. In this method, the pressure of the tire-shaped ultrasonic probe against the surface of the specimen is reduced due to the relatively small amplitude but high-speed vibration of the support of the tire-shaped ultrasonic probe caused by the running of the cart. The efficiency of transmitting and receiving surface waves to and from the surface of the object is unstable.

In addition, it is possible to improve the drawbacks of the spring and air cylinder devices described above, to make the ultrasonic probe follow the surface of the object well, and to press the ultrasonic probe against the surface of the object with a constant pressure. As an invention made for the purpose of
Although there is a device for pressing a probe using a multi-stage air cylinder device (No. 128241), this multi-stage air cylinder device has the disadvantage that it has a complicated structure and is very difficult to handle.

The present invention uses a simple and easy-to-handle structure to enable a tire-shaped probe to closely follow the surface of an object, press it with a constant pressure, and send and receive surface waves to and from the surface of the object with constant efficiency. The purpose of this test is to perform stable inspections for surface defects on specimens.

[Means for Solving the Problems] The present invention uses a tire-shaped ultrasonic probe that is rotatably held in a probe holder to propagate surface waves to the surface of an object to be examined. A surface flaw inspection device that inspects surface flaws includes a support that is movable relative to the test object in the test direction of the test object, an F cylinder device disposed on the support, and a piston of an air cylinder device. The probe includes a spring interposed between the rod tip and the probe holder.

[Function] In the present invention, vibrations of the support or the object due to relative movement between the support and the object, that is, small amplitude but high-speed vibrations, are absorbed by the expansion and contraction of the spring, and bending of the object is absorbed. It is possible to absorb the vibrations of the support body due to this, that is, the low-speed vibrations with large amplitudes, by expanding and contracting the air cylinder device. Therefore, according to the present invention, by using a simple and easy-to-handle UI structure, the tire-shaped probe can be made to follow the surface of the subject well and pressed with a constant pressure, and the surface of the tire-shaped probe can be pressed against the surface of the subject with a constant efficiency. By transmitting and receiving waves, it becomes possible to stably inspect the surface of a subject for defects.

[Example] FIG. 1 is a front view showing a surface flaw inspection apparatus 10 according to an example of the present invention, and FIG. 2 is a side view of FIG. 1.

The surface flaw inspection device 10 propagates surface waves onto the surface of a large diameter steel pipe 13 as a test object using a tire-shaped ultrasonic probe 12 that is rotatably held in a probe holder 11. surface flaws can be inspected. The tire-shaped ultrasonic probe 12 has a built-in ultrasonic transducer (not shown).

The surface flaw inspection device 10 has a support 14 that is movable relative to the steel pipe 13 in the inspection direction of the steel pipe 13. The support body 14 is attached to a truck running along the steel pipe 13, or to a fixed start/start placed opposite to the running steel pipe 13.

The surface flaw inspection apparatus 10 has an air/linda device 15 disposed on the support 14 shown in h. A spring holding plate 17 is fixed to the tip of the piston rod 16 of the air cylinder device 15, and the probe holder 11 and the spring holding plate 17
A compressor pull 18 is interposed between the two. Here, although the air cylinder device 15 has poor responsiveness, it can sufficiently absorb vibrations of low speed and large amplitude.

Further, the compression spring 18 can absorb even high-speed vibrations as long as the amplitude is small.

Note that the probe holder 11 has a plurality of (four in this embodiment)
The guide rod 19 of the book) is fixed, and the guide rod 19 is
The probe holder 11 and the spring press plate 1 pass through the guide hole 17A provided in the spring press plate 17, and further penetrate the guide hole 14A provided in the support body 14.
A compression spring 18 is loosely installed around the part that extends between 7 and 7.

In other words, the first surface flaw inspection device f1to is the air cylinder Mi.
The tire-shaped ultrasonic probe 12 is supported on the support body 14 under the expansion and contraction of W15 and the compression spring 18, and it is possible to press the tire-shaped ultrasonic probe 12 against the surface of the steel pipe 13 with a constant pressure. At this time, the probe holster it slides the guide rod 19 against the guide hole 17A of the spring holding plate 17 and the guide hole 14A of the support body 14, and the tire-type ultrasonic probe 12 slides into the air cylinder assembly 3115. , it is possible to prevent the compression spring 18 from swinging in the front, back, left and right directions orthogonal to the direction of expansion and contraction. Further, the compression spring 18 is stably held around the guide rod 19 between the probe holder 11 and the spring holding plate 17.

Next, the operation of the above embodiment will be explained. As described above, this surface flaw inspection device 10 includes a support body 14 and a steel pipe 13.
Harmful flaws on the surface of the steel pipe 13 can be detected under conditions in which the steel pipe 13 moves relatively in the inspection direction.

At this time, vibrations of the support body 14 or the steel pipe 13 due to relative movement between the support body 14 and the steel pipe 13, that is, vibrations having a small amplitude but high speed, are absorbed by the expansion and contraction of the compression spring 18. Furthermore, fluctuations in the distance between the support body 14 and the large-diameter steel pipe 13 due to bending of the steel pipe 13, that is, low-speed vibrations with large amplitudes, are absorbed by the expansion and contraction of the air cylinder device 15.

Therefore, according to the above-mentioned surface flaw inspection device IO, surface waves can be transmitted and received to and from the surface of the steel pipe 13 with a certain efficiency, with a simple and easy-to-handle structure, and the surface of the steel pipe 13 can be stably
This makes it possible to inspect surface flaws.

Note that the present invention is widely applicable not only to steel pipes but also to surface flaw inspections of steel plates and the like.

[Effects of the Invention] As described above, the present invention uses a tire-shaped ultrasonic probe that is rotatably held in a probe holder.

In a surface flaw inspection device for inspecting surface flaws on a test object by propagating surface waves on the surface of the test object, a support member movable relative to the test object in an inspection direction of the test object; The probe holder includes an air cylinder device disposed in the air cylinder device, and a spring interposed between the tip of the piston rod of the air cylinder device and the probe holder.

Therefore, with a simple and easy-to-handle structure, the tire-shaped probe can be made to follow the surface of the object well, and pressed with a constant pressure, and the surface waves can be transmitted and received to and from the surface of the object with a certain efficiency. It becomes possible to stably inspect the surface flaws of the subject.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a surface flaw inspection apparatus according to an embodiment of the present invention, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a sectional view showing a general surface wave excitation method. FIG. 4 is a schematic diagram showing a method of transmitting and receiving surface waves using a tire-shaped ultrasonic probe. lO...Surface flaw inspection device, 11...Probe holder,
12... Tire-shaped ultrasonic probe, 13... Steel pipe. 14... Support body, 15... Air cylinder device, 18
...Compression spring.

Claims (1)

[Claims] (1) In a surface flaw inspection device that inspects surface flaws on a test object by propagating surface waves onto the surface of the test object using a tire-shaped ultrasonic probe that is rotatably held in a probe holder,
A support that is movable relative to the test object in the test direction of the test object, an air cylinder device disposed on the support, and a space between the piston rod tip of the air cylinder device and the probe holder. 1. A surface flaw inspection device comprising: a spring interposed in the surface flaw inspection device;