JP2000356626A - Immersed ultrasonic detecting method by single detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make increasable the feeding mount of a material per one rotation to tow times of an effective beam width by providing one channel with two gates for detecting flaw on both of inner and outer surfaces, and changing the flaw detecting allocation of the channel. SOLUTION: The flaw of a material to be detected having an outer diameter ϕof approximately 13-95 mm, and a thickness of below 20% of the outer diameter, such as bearing general steel, stainless alloy steel, tool steel or the like is detected by using a flaw detector having an effective beam width of a probe of approximately 5 mm, and the frequency of probe of approximately 4 MHz. One channel is provided with two gates, and the flaw on inner and outer surfaces of a material to be detected, is detected by the clockwise flaw detection and the anticlockwise flaw detection by the probe. C1, C3 indicate the clockwise flaw detection, and C2, C4 indicate the anticlockwise flaw detection of the inner and outer surfaces. The flaw detection is allocated to each channel, and a feeding amount of the material 1 per one rotation can be increased by two times of an effective beam width of the probe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water immersion ultrasonic flaw detection method using one method.

[0002]

2. Description of the Related Art Conventionally, a flaw detection element (hereinafter, referred to as a probe) has been used to detect a flaw in a thick steel tube using a water immersion ultrasonic flaw detector.
A method of transmitting and receiving ultrasonic waves by one device (hereinafter referred to as one search method) is used. FIG. 4 is a diagram showing a waveform and an overcheck state in a thin steel tube product and a thick steel tube product. FIG.
4A shows a waveform of a thin steel pipe, and FIG. 4B shows a waveform of a thick steel pipe. As shown in FIG. 4 (b), in the case of a thick-walled steel pipe, the signals of the outer surface flaw and the inner surface flaw are separated, so that there is only one flaw detection gate per channel. To detect both inner surface flaws with one channel, it is necessary to increase the gate width L.
However, if the gate width L is widened, as shown in FIG. 4C, various types of noise E are detected and overcheck is performed. Therefore, the gate width L must be as small as possible.

[0003] In order to avoid over-checking during flaw detection of thick steel pipes, as shown in FIG. 4D, flaws are detected by inner surface flaws (C1 to C2) and outer flaws (C3 to C4). It is necessary to divide channels and assign different gates. In order to detect the entire surface of the product with the inner and outer surfaces, clockwise, and counterclockwise without flaws using this method, as shown in FIG. 5, the feed per rotation of the material must be the effective beam width of the ultrasonic wave of the probe. No. That is, FIG. 5 is a diagram showing channel assignment in the conventional single-detection flaw detection.
As shown in this figure, the fact that the feed amount per rotation of the material to be detected is set to the effective beam width L of the ultrasonic wave of the probe is to advance to A ₀ -A ₁ per rotation of the material in FIG.

[0004]

As described above, in order to avoid over-checking at the time of flaw detection of a conventional thick steel pipe, it is necessary to divide flaw detection channels for inner surface flaws and outer surface flaws and to assign separate gates. To detect flaws on the entire surface of the product by using this method, both inside and outside, clockwise and counterclockwise, the amount of feed per rotation of the material must be the effective beam width of the ultrasonic wave of the probe. Therefore, there was a problem that productivity was hindered.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the inventors have intensively developed and as a result, one channel has two gates, and the flaw detection assignment of the channel is changed. Another object of the present invention is to provide a water immersion ultrasonic flaw detection method using one method which enables the feed per rotation of the material to be twice the effective beam width. The gist of the invention is that in water immersion ultrasonic flaw detection by one detection method, it is possible to detect both inner and outer surface flaws by one channel by providing two gates in one channel. The present invention is directed to a water immersion ultrasonic flaw detection method based on one method, wherein the amount of feed per flaw detection material is increased by changing the flaw detection assignment to increase the effective beam width of the flaw detection element.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a flaw detection direction. As shown in this figure, a steel pipe 2 as a test material is subjected to a clockwise flaw detection 3 and a counterclockwise flaw detection 4 by a probe 1 to perform a clockwise flaw detection on the inner and outer surfaces and a counterclockwise flaw detection on the inner and outer faces. is there. FIG. 2 is a schematic diagram of the one-gate flaw detection / allocation flaw detection method according to the present invention. In this figure, C1 and C3 indicate flaw detection in the clockwise direction on the inner and outer surfaces, and C2 and C4 indicate flaw detection in the counterclockwise direction on the inner and outer surfaces. As shown in this figure, by assigning flaw detection to each channel, as shown in FIG.
The feed amount per rotation can be twice the effective beam width L of the probe.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS For detecting flaws of a material to be inspected having an outer diameter of 13 to 95 mm and a wall thickness of 20% or less of an outer diameter made of bearing general steel, stainless high alloy steel, tool steel, and the like, the probe effective beam width: 5 mm, the probe By using a flaw detection device with a frequency of 4 Mhz, one channel is provided with two gates, and by changing the flaw detection assignment of the channel, it is possible to detect both inner and outer flaws with one channel, and the material 1
The present invention relates to a water immersion ultrasonic flaw detection method by one method which enables the feed per rotation to be twice the effective beam width. As a result, it has become possible to improve the productivity twice as compared with the case using the conventional flaw detector.

[0008]

As described above, the present invention makes it possible to double the effective beam width compared to the conventional water immersion ultrasonic inspection method in detecting flaws in a thick steel pipe, thereby improving productivity. This is an extremely excellent effect that can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a flaw detection direction.

FIG. 2 is a schematic diagram of a two-gate, one-detection flaw detection assignment flaw detection method according to the present invention.

FIG. 3 is a diagram showing an image of each channel flaw detection in one flaw detection at the time of two gates.

FIG. 4 is a diagram showing a waveform and an overcheck state in a thin steel tube product and a thick steel tube product.

FIG. 5 is a diagram showing channel assignment for conventional one-detection flaw detection.

[Description of Signs] 1 Probe 2 Steel pipe 3 Clockwise inspection 4 Counterclockwise inspection C1, C3 Internal and external clockwise inspection C2, C4 Internal and external counterclockwise inspection L Beam width

Claims (1)

[Claims] In the water immersion ultrasonic flaw detection by one method,
By providing two gates in one channel, it is possible to detect both the inner and outer surface flaws in one channel, and by changing the flaw detection allocation of the channel, the feed amount per material to be inspected can be changed. A water immersion ultrasonic flaw detection method according to one method, wherein the effective beam width is increased.