JP2002122575A - Method and apparatus for angle beam method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus, for an angle beam method, wherein a transverse crack flaw existing in the corner part of a square steel billet is detected surely by using ultrasonic waves. SOLUTION: The ultrasonic waves are transmitted, at a prescribed angle θ, to the corner part region of the square steel billet 11 in such a way that the ultrasonic waves are propagated in the inside of the steel billet 11 in its longitudinal direction. Reflected waves of the transmitted ultrasonic waves are detected, thereby, detects the transverse crack flaw in the corner part region of the steel billet 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic angle beam inspection method and an ultrasonic angle beam inspection apparatus. More specifically, the present invention relates to an ultrasonic bevel flaw detection method and an ultrasonic bevel flaw detector suitable for detecting a lateral crack generated in a corner of a square steel slab using ultrasonic waves.

[0002]

2. Description of the Related Art Conventionally, materials such as bolts and other mechanical structural parts have been suitable for the manufacture of bolts and other intermediate products of so-called square shaped steel, which are steel pieces having a prismatic shape with a side of about 200 mm. It is rolled into a cross-sectional shape and shipped.

[0003] However, if the surface of the billet is damaged, problems such as breakage of bolts manufactured from the shipped material may occur. At the stage, the surface is also inspected for flaws.

For this reason, a flaw detection method and a flaw detection apparatus for inspecting the surface of a steel piece for flaws have been developed, and induction flaw detection, ultrasonic surface waves, and the like are used for the flaw detection.

Hereinafter, the principle and problems of the flaw detection using the induction heating flaw detection and the ultrasonic surface wave will be described with reference to FIG. 4 and FIG. FIG. 4 is a diagram for explaining the outline and problems of the principle of the induction heating flaw detection method, and FIG. 5 is a diagram for explaining the outline and problems of the principle of the ultrasonic surface wave method. .

The induction heating flaw detection method utilizes the fact that when an induction current is applied to an induction coil 42 disposed around the steel slab 41, a temperature change occurs around the flaw of the steel slab 41, and the temperature of the steel slab 41 is changed. This is to detect flaws. However, although this induction heating flaw detection method is effective for flaw detection 43 (longitudinal flaw) in the direction perpendicular to the direction in which the induction current flows,
When the direction in which the induced current flows and the direction of the scratches 44 (lateral cracks) of the steel slab 41 coincide with each other, the temperature change around the lateral cracks 44 due to the induced current is small. Absent.

The ultrasonic surface wave method transmits ultrasonic waves from the probe 52 along the surface of the steel piece 51 and detects reflected waves reflected by the flaw, thereby detecting flaws on the steel piece 51. Is what you do. However, when the direction of the scratch 53 (lateral crack) of the billet 51 is the same as the transmission direction 54 of the ultrasonic wave, the reflection at the transverse crack 53 is small and there is reflection noise at the corner of the billet 51. However, such an ultrasonic surface wave method is not suitable for detecting the lateral crack 53.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and it is an object of the present invention to reliably detect a lateral crack at a corner of a rectangular steel slab by using ultrasonic waves. It is an object of the present invention to provide an ultrasonic oblique flaw detection method and an ultrasonic oblique flaw detection apparatus that can perform the above method.

[0009]

According to the ultrasonic oblique flaw detection method of the present invention, an ultrasonic wave is transmitted at a predetermined angle to a corner region of a rectangular steel slab so that the ultrasonic wave propagates inside the steel slab in the longitudinal direction. And
By detecting the reflected wave of the transmitted ultrasonic wave, a flaw in the corner portion of the billet is detected.

In the ultrasonic oblique flaw detection method of the present invention,
For example, ultrasonic waves are transmitted to all corners of a billet. In the ultrasonic oblique flaw detection method of the present invention, when a reflected wave of an ultrasonic wave transmitted to a corner area of a steel slab is detected, it is determined that a lateral crack is present in the corner area of the steel slab.

On the other hand, the ultrasonic bevel flaw detector of the present invention transmits an ultrasonic wave at a predetermined angle to a corner region of a steel slab so that the ultrasonic wave propagates inside the steel slab in the longitudinal direction, and reflects the reflected wave. And a flaw detecting means for determining a flaw based on the reflected wave detected by the ultrasonic transmitting / receiving means.

In the ultrasonic bevel flaw detector of the present invention,
For example, ultrasonic waves are transmitted to all corners of a billet.

Here, the predetermined angle is, for example, 30 ° to
The angle is set to 70 °, and the billet is made of a non-magnetic material.

[0014]

Since the present invention is constructed as described above, it is possible to reliably detect a lateral crack in the corner area of the rectangular steel slab without being affected by the condition of the surface skin of the rectangular steel slab or the external environment. It becomes possible.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments with reference to the attached drawings, but the present invention is not limited to only such embodiments.

First, the principle of an ultrasonic oblique flaw detection method using ultrasonic waves according to an embodiment of the present invention will be described with reference to FIG. FIG. 1A is a diagram showing the propagation direction of ultrasonic waves in the case where there is no lateral crack in the corner of the rectangular steel slab, and FIG. 1B is a diagram showing the lateral crack in the corner of the rectangular steel slab. FIG. 7 is a diagram showing the propagation direction of an ultrasonic wave in the case where there is a wave; The square steel is a non-magnetic material.

As shown in FIGS. 1A and 1B, the ultrasonic waves I1 and I2 are transmitted from the probe (ultrasonic transmitting / receiving means) 12 to the corner region C of the steel slab 11. Ultrasonic waves I1 and I2 are transmitted at a predetermined angle θ in the longitudinal direction of the rectangular steel slab 11. The predetermined angle θ is, for example, in the range of 30 ° to 70 °.

If there is no lateral crack in the square-shaped billet (hereinafter simply referred to as the billet) 11, ultrasonic waves are reflected at the corner region C of the billet 11 as shown in FIG. That is, the ultrasonic wave R1 propagates in the longitudinal direction of the steel slab 11, and the probe 12 does not detect the ultrasonic wave (reflected wave).

On the other hand, a lateral crack 1
1B, the ultrasonic wave is reflected by the lateral crack 13 and the ultrasonic wave (reflected wave) R2 reflected by the lateral crack 13 is moved to the position of the probe 12 as shown in FIG. Returning to the vicinity, the ultrasonic wave is detected by the probe 12.

That is, the ultrasonic oblique flaw detection method uses the steel slab 1
In the case where ultrasonic waves are transmitted in the longitudinal direction of
The ultrasonic wave is detected by the probe 12 when there is a lateral crack in the corner region of No. 1 and the ultrasonic wave is not detected by the probe when there is no lateral crack. This is to detect a lateral crack in the area.

Next, an outline of the configuration of an ultrasonic angle beam inspection apparatus according to an embodiment of the present invention to which the ultrasonic angle beam inspection method is applied will be described with reference to FIG. 2 and FIG.

The ultrasonic bevel flaw detector transmits four ultrasonic waves and detects the ultrasonic waves.
2b, 22c, 22d, an excitation device 23 for inputting a voltage signal to each angle probe, and a flaw detection device 24 having a display device 24a for displaying a voltage signal from each angle probe. Have been.

Each of the oblique probes 22a, 22b, 22c, 2
In 2d, an ultrasonic wave is oscillated when an AC voltage signal is applied to the vibrator and the vibrator vibrates, and when the ultrasonic wave is received, the vibrator vibrates and a voltage is generated to detect the ultrasonic wave. It is known. Here, the oblique probes 22a, 22b, 22c and 22d are arranged so as to transmit ultrasonic waves to the flaw detection areas A1, A2, A3 and A4 of the steel piece 21 as shown in FIG. The scanning direction of each of the oblique probes 22a, 22b, 22c and 22d is
In the longitudinal direction.

The excitation device 23 has a frequency (1 KHz to 10 KHz).
KHz) and oscillates each of the oblique probes 22 as an output from the AC voltage source as a voltage signal.
a, 22b, 22c and 22d.

The flaw detection device (flaw detection means) 24 is a personal computer having a display device 24a such as a CRT display.

Hereinafter, the operation of the ultrasonic oblique flaw detector configured as described above will be described.

The voltage signal oscillated by the excitation device 23 is input to the angled probes 22 a, 22 b, 22 c, 22 d, and the angled probes 22 a, 22 b, 22 c, 22 d are put into the steel piece 21 by ultrasonic waves. At a predetermined angle θ. If the transmitted ultrasonic wave has a lateral crack in the corner, it is reflected by the damage and the reflected waves are reflected by the oblique probes 22a, 22b, 22.
c, 22d. The detection signal is converted into a voltage signal, and the converted voltage signal is
And is displayed on the display device 24a. The scratch detection device 24 determines that there is a lateral crack at the corner of the billet 21 when the input voltage value exceeds the threshold, and determines the corner of the billet 21 when the input voltage value does not exceed the threshold. It is judged that there is no lateral crack.

As described above, the ultrasonic bevel flaw detector of the present embodiment transmits ultrasonic waves at a predetermined angle inside the corner of the steel slab, and detects the ultrasonic waves reflected by the flaws. Because it is to detect lateral cracks in the corners,
It is less susceptible to the influence of the surface skin of the billet and the external environment, and it is possible to reliably detect a lateral crack.

In the above-described embodiment, ultrasonic waves are transmitted to the corner region at a predetermined angle in order to detect a lateral crack generated in the corner region of the square billet. The incident wave is incident on the inner wall surface around the corner region in a range of an incident angle smaller than the surface wave, for example, in the range of 30 to 40 degrees, and the reflected wave from the flaw around the corner region of the billet is detected. Thereby, it is also possible to detect a flaw in the longitudinal direction generated near the corner of the steel slab.

As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to only such embodiments, and various modifications are possible. For example, instead of performing transmission and reception of ultrasonic waves by the same angle beam probe, the ultrasonic waves may be transmitted by separate angle beam probes. Further, in the present embodiment, the square steel slab is made of a non-magnetic material, but may be made of a magnetic material.

[0031]

As described in detail above, according to the present invention,
An excellent effect that a lateral crack in a steel slab can be reliably detected can be obtained.

[Brief description of the drawings]

FIG. 1 is a view for explaining the principle of the ultrasonic oblique flaw detection method, wherein FIG. 1 (a) shows the propagation direction of ultrasonic waves when there are no lateral cracks in the corners of the rectangular steel slab. (B) shows the propagation direction of the ultrasonic wave in the case where there is a lateral crack at the corner of the square steel slab.

FIG. 2 is a diagram schematically illustrating a configuration of an ultrasonic oblique flaw detection apparatus to which the ultrasonic oblique flaw detection method is applied.

FIG. 3 is a diagram showing the arrangement of the oblique probe and the transmission direction of ultrasonic waves from the oblique probe, wherein FIG.
(B) is a partially enlarged view.

FIG. 4 is a diagram for explaining the outline of the principle and problems of the induction heating flaw detection method.

FIG. 5 is a diagram for explaining an outline of the principle of the ultrasonic surface wave method and a problem.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Slab 12 Bevel probe 13 Lateral crack 21 Slab 22a Bevel probe 22b Bevel probe 22c Bevel probe 22d Bevel probe 23 Exciting device 24 Scratch detector 24a Display device

Claims (9)

[Claims] An ultrasonic wave is transmitted at a predetermined angle to a corner region of a rectangular slab so that the ultrasonic wave propagates inside the slab in the longitudinal direction, and a reflected wave of the transmitted ultrasonic wave is detected. An ultrasonic oblique flaw detection method, wherein flaws are detected in the corner area of the steel slab. 2. The ultrasonic oblique flaw detection method according to claim 1, wherein the predetermined angle is in a range of 30 ° to 70 °. 3. The ultrasonic oblique flaw detection method according to claim 1, wherein ultrasonic waves are transmitted to all corners of the steel slab. 4. The method according to claim 1, wherein when a reflected wave of the ultrasonic wave transmitted to the corner area of the billet is detected, it is determined that a lateral crack is present in the corner area of the billet. Ultrasonic angle beam inspection method. 5. The ultrasonic oblique flaw detection method according to claim 1, wherein the steel slab is made of a non-magnetic material. 6. An ultrasonic transmitting / receiving means for transmitting an ultrasonic wave at a predetermined angle to a corner region of a rectangular slab so that the ultrasonic wave propagates in the inside of the slab in the longitudinal direction, and detects a reflected wave thereof. And a flaw detection means for determining flaws based on the reflected wave detected by the ultrasonic transmission / reception means. 7. The ultrasonic oblique flaw detector according to claim 6, wherein the predetermined angle is in a range of 30 ° to 70 °. 8. The ultrasonic bevel flaw detector according to claim 6, wherein ultrasonic waves are transmitted to all corners of the steel slab. 9. The ultrasonic oblique flaw detector according to claim 6, wherein the steel slab is made of a non-magnetic material.