JPH0325745B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic ultrasonic flaw detection device for non-destructively testing steel products such as round bars or pipes using ultrasonic waves.

[Conventional technology]

This type of conventional device will be explained with reference to FIGS. 3 and 4.

FIG. 3 conceptually shows a conventional apparatus for inspecting a test material using an ultrasonic automatic flaw detection device, and FIG. 4 shows a conveying ski roll in FIG. 3.

In Figures 3 and 4, 1 is a test piece such as a round bar to be inspected with an automatic ultrasonic flaw detector, and 2 is a chain with a preset angle of θ shown in the figure and the center of the test piece 1 in the conveying direction. 2a and 2 are rotated by a ski roll that transports the test material at a constant rotation pitch.
It consists of a combination of b, 2c and 2d, and 2e and 2f.
3 is a motor for rotating the ski roll 2; 4 is a variable speed controller for rotating the motor 3 at a required constant speed; 5 is a miter gearbox for changing the direction of rotation of the motor and transmitting rotational force. ,6
The chain coupling spring gear box 7, which further changes the direction of the rotation of the miter gear box 5 and connects with the chain to rotate the ski roll, transmits the rotational force of the motor 2 to each of the miter gear boxes 5a, 5b, and 5c. 7 with the shaft of
It consists of a and 7b. Reference numeral 8 denotes a photoelectric sensor that emits a signal the moment the light is blocked by the material to be inspected, and 8a and 8c are photoelectric sensor projectors 8b and 8d are 8a and 8c, respectively.
9 is a mechanical part of an automatic ultrasonic flaw detection device; 10 is a mechanical part of the ultrasonic automatic flaw detection device; 10 is a mechanical part of the ultrasonic automatic flaw detection device; three sets of flaw detection heads attached to the mechanical part 9 are brought into contact with the material to be inspected, and individual 3 sets 10 to follow the flaw detection head
The tracking devices 11 a, 10b, and 10c are attached to the tracking devices and include three sets 11a, 11b, and 11 that accommodate ultrasonic probes that transmit and receive ultrasonic waves to the specimen 1.
c, a flaw detection head 12, a computing unit for controlling contact or separation of the head 11 of the tracking device 10 and calculating the speed of the material to be inspected; and 13, a calculator for transmitting the rotation of the chain spring gear box 6 to the ski roll. The chain consists of two sets 13a and 13b and rotates ski rolls in the same direction. 14 is a gear coupling for decelerating and transmitting the rotation of the motor 3, and 15 is a pedestal for supporting the skid roll 2.

The conveyance speed when the test material is transported by the skil roll 2 is a function of the angle θ and the rotation speed of the skil roll, but in most cases it cannot be uniquely determined due to slippage between the test material and the skil roll.

Conventionally, two sets of photoelectric sensors 8a and 8b and 8c and 8d installed at fixed positions on the conveyance line are used to measure time from the moment the material to be inspected blocks light from the photoelectric sensors 8a and 8b, and the next photoelectric sensor 8c is used. A method has been adopted in which the measurement is stopped at the time when 8d and 8d are shielded from light, and the conveyance speed is determined using the measured time to determine the contact timing of the flaw detection head 11.

As shown in FIG. 3, the distance L ₁ between the photoelectric sensors 8a and 8c, the photoelectric sensor 8a and the tracking devices 10a,
Let the distances between 0b and 10c be L ₂ , L ₃ and L ₄ , respectively.
Assuming that the measurement time during which the test material shields the photoelectric sensors 8a and 8c is T ₁ (seconds), the velocity V ₁ of the test material is determined by the calculator 12 as V ₁ =L ₁ /T ₁ ...(1) It will be done. Therefore, the contact timing of the tracking device 10a is the time after the photoelectric sensor 8a is shielded from light.
Calculate T ₂ .

L ₂ /V ₁ = T ₂ ...(2) This is the moment when formula (2) is established.

Similarly, the contact timing of the tracking devices 10b and 10c is the time _T3 after the photoelectric sensor 8a is shielded from light.
Calculate T ₄ to find.

L ₃ /V ₁ = T ₃ ...(3) L ₄ /V ₁ =T ₄ ...(4) Equation (3) is the contact timing of the flaw detection head 11b, and equation (4) is the contact timing of the flaw detection head 11c. .

[Problem that the invention seeks to solve]

When testing the entire area using an ultrasonic automatic flaw detection device, it is necessary to connect the flaw detection head 11 to the tip of the test material, and the contact timing determined from equations (2), (3), and (4) above is based on the test material. The conventional method can only be applied when the material is transported at a constant speed, but when the speed changes, the conventional method cannot be applied. In particular, when conveying with skiwl rolls, the rotational force of the skiwl rolls is divided into vectors in the conveying direction and rotational direction, so it is easy to slip due to the bending of the material to be inspected, the roughness and density of the surface, etc., and it is difficult to constantly convey it at a constant speed. Ta. If a slip in the material to be inspected occurs between the photoelectric sensors (between 8a and 8c), the speed of the material to be inspected will be slower than the measurement speed _V1 , resulting in a difference in the timing of contact, and in the worst case, flaw detection will be delayed. Sometimes the head falls first and then the material to be inspected is transported, destroying the flaw detection head.

This invention was made in order to solve this problem and to accurately determine the speed of the test material even when the speed of the test material changes, and to find an appropriate contact timing.

[Means for solving problems]

Since the conveying speed is related to the set angle θ and the rotation speed of the ski roll, this invention uses a rotation detector that generates rotation pulses on the rotation axis of the ski roll, a counter that counts the pulses, and a fixed position in front of the conveyance direction near the flaw detection head. Two sets of photoelectric sensors are provided at different positions, and the set angle θ of the ski roll, the pulse count value, and the photoelectric sensor signal are input to a computing unit to determine the conveyance speed and appropriate timing for contacting the material.

[Effect]

θ is the setting angle of the ski roll, N is the rotation speed of the ski roll per second, φ ₁ (mm) is the outer diameter of the material to be inspected, φ ₂
When (mm) is the outer diameter of the ski roll, the conveyance speed V ₅ (mm) is determined by the following formula.

V ₅ =k·φ ₂ /φ ₁ ·N·cosθ (mm/sec) (5) k is a coefficient that differs depending on the outer diameter of the material to be inspected, including slips during transportation. The number of rotations of the ski roll is converted into pulses by a rotation detector and counted every second by a counter. The count value is input to a calculator, and the transport speed _V5 is determined by calculating the equation (5). At the same time, the conveyance speed V ₁ is determined by the above equation (1). Calculating the speed ratio X ₁ between the two: X ₁ = V ₁ /V ₅ ...(6) Measure between the photoelectric sensors (between 8a and 8c)
Since V ₁ is the measured speed between the photoelectric sensors, it is the actual speed, and if X ₁ is 1, the calculated speed V ₅ matches the actual speed. Even if they do not match, the speed _V5 can be corrected by _X1 .

Therefore, the following equations (7), (8), and (9), which correct the contact timings ( ₂ ), ( ₃ ), and ( ₄ ) above, are calculated based on the respective flaw detection values. This is a formula that provides appropriate contact timing for the heads 11a, 11b, and 11c.

L ₂ = _t=T2 ′ 〓 ^t=0 (X ₁ V ₅ ) ……(7) L ₃ = _t=T3 ′ 〓 ^t=0 (X ₁ V ₅ ) ……(8) L ₄ = _t=T4 ′ 〓 ^t=0 (X ₁ V ⁵ ) ...(9) Since the calculation speed is corrected by the actual speed between the photoelectric sensors, if the slip rate does not change, the calculation speed after this is considered to be approximately the actual speed.

〔Example〕

Embodiments of the present invention will be described below with reference to FIG. 1, which conceptually shows the entire apparatus, and FIG.
This will be explained using figures.

In FIGS. 1 and 2, numerals 1 to 15 are exactly the same as the conventional device. Reference numeral 16 denotes a rotation detector which is connected to the rotating shaft of the ski roll 2 through a coupling and generates a pulse signal corresponding to the number of rotations of the ski roll. Reference numeral 17 denotes a counter that counts the pulses generated by the rotation detector 16.

Set the ski roll angle in advance (5) above.
Count the pulses and calculate the transport speed using the formula, and at the moment the material to be inspected blocks light from the photoelectric sensor, calculate the speed _ratio The distance is calculated by integrating the count values.

The times T ₂ ′, T 3 ′, and T 4 ′ at which the cumulative distances become equal to L ₂ , L ₃ , and L ₄ in equations (7), (8), and (9) are the times T 2 ′, T ₃ ′, and T ₄ ′ for each flaw detection head 11a, 11b, and 11c. This is the timing for welding.

〔Effect of the invention〕

Equations (7), (8), and (9) above are functions of the rotation speed even when the speed is varied by changing the rotation speed, so not only can the speed be determined by calculation, but it can also be used for photoelectric sensors. Since the actual speed is measured in between, there is a section in which the difference between the calculated speed and the calculated speed is corrected, so the calculated speed can be brought closer to the actual speed.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the conveying ski roll in FIG. 1, FIG. 3 is a conceptual diagram showing a conventional device, and FIG. 4 is a conceptual diagram showing the conveying ski roll in FIG. 3. FIG. In the figure, 1 is the material to be tested, 2 is Skyuroll, and 3 is
is a motor, 4 is a variable speed controller, 5 is a miter gearbox, 6 is a chain coupling spring gearbox,
7 is a shaft, 8 is a photoelectric sensor, 9 is a mechanism part, 1
0 is a tracking device, 11 is a flaw detection head, 12 is a computing unit, 13 is a chain, 14 is a gear coupling,
15 is a frame, 16 is a rotation detector, and 17 is a counter. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In order to detect defects over the entire area of a test material such as a round bar or pipe that is conveyed at a constant pitch by rotation of a skew roll with a skew angle set in advance, a flaw detection head equipped with a probe is placed at the tip of the test material. The automatic ultrasonic flaw detection device is lowered to The rotation detector and the counter have a counter that counts rotation pulses and a computing unit that calculates the count value of the counter, and that detects the speed of the specimen conveyed by the skew roll, the skew angle, and the rotation speed of the skew roll. Further, the distance is calculated using the photoelectric sensor installed at the fixed position as a starting point to generate the timing for lowering the flaw detection head, and the two sets of photoelectric sensors spaced apart by a certain distance are shielded from light by the material to be inspected. The ultrasonic automatic apparatus is characterized in that the dead zone is reduced by lowering the flaw detection head to the tip of the test material by comparing the speed of the test material determined from the time difference between the flaw detection head and the flaw detection head lowering timing determined by the calculation described above. Flaw detection equipment.