Ultrasonic surface wave probe zero offset, leading edge and sound velocity calibration method

Abstract

The invention discloses an ultrasonic surface wave probe zero offset, leading edge and sound velocity calibration method. The method comprises the following steps: 1) preparing and selecting a test block; 2) positioning a probe to be detected; 3) performing initial resetting, and zeroing a zero offset parameter and a leading edge parameter; 4) translating the probe, and determining the echo time of the last stage before the upper end angle signal disappears as a zero offset parameter; 5) moving the probe until the front edge of the probe is flush with the side surface of the test block, and determining the echo time at the upper end corner of the test block as a front edge parameter; 6) calculating and calibrating a sound velocity value by using the primary echo time at the lower end angle and the secondary echo time at the lower end angle; the standardization and calibration precision of the calibration process are improved, and measurement errors caused by an existing method can be avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of ultrasonic flaw detection and monitoring, and in particular relates to a method for calibrating zero bias, front edge and sound velocity of an ultrasonic surface wave probe. Background Art

[0002] During ultrasonic testing, the front length of the probe (the distance from the ultrasonic beam incident point to the front end of the probe) is an important parameter of the probe and an important factor affecting defect location. Therefore, each time ultrasonic testing is performed, the front length of the probe must be accurately measured (i.e., calibrated).

[0003] When calibrating the probe manually, firstly, the selected probe should be electrically connected to the ultrasonic flaw detector (hereinafter referred to as the flaw detector), and the front length of the probe should be measured on the test block. Then, the measured parameters and the specification data of the workpiece to be tested should be input into the flaw detector to obtain the flaw detection curve, and then the test can be carried out. Due to different operating habits and proficiency of each person, the measured front length is slightly different.

[0004] After measuring the leading edge length of the probe, ultrasonic flaw detection calibrates the sound velocity of the surface wave based on the measured zero bias and leading edge data, as well as the distance from the probe end face to the reflector. In this process, the zero bias, leading edge, and reflector distance are all measured manually, which often involves many uncertain factors, causing large errors in the measurement results and hindering the accurate measurement of ultrasonic surface waves. Summary of the invention

[0005] The purpose of the present invention is to improve the standardization of the calibration process and the calibration accuracy, and to provide a method for calibrating the zero bias plus leading edge and the sound velocity of an ultrasonic surface wave probe.

[0006] A method for calibrating zero bias, front edge and sound velocity of an ultrasonic surface wave probe, characterized by comprising the following steps:

[0007] Step 1) preparing and selecting test blocks;

[0008] Step 2) positioning the probe to be tested;

[0009] Step 3) Initial reset, zero bias parameters and leading edge parameters are all reset to zero;

[0010] Step 4) the probe is translated, and the echo time in the last stage before the upper corner signal disappears is determined as the zero bias parameter;

[0011] Step 5) Move the probe until the front edge of the probe is flush with the side of the test block, and the echo time at the upper corner of the test block is determined as the front edge parameter;

[0012] Step 6) Calculate and calibrate the sound velocity value using the first echo time at the lower corner and the second echo time at the lower corner.

[0013] The beneficial effects of the present invention are:

[0014] Compared with the prior art, the present invention designs a method for calibrating ultrasonic surface wave probe zero bias plus front edge and sound velocity, which improves the standardization of the calibration process and the calibration accuracy through ultrasonic surface wave probe zero bias plus front edge and sound velocity calibration, and can avoid the measurement error caused by the prior method. It can achieve multiple calibration tasks on a test block, including sound velocity, zero bias, and front edge calibration, reduce the number of test blocks, and increase the rationality and accuracy of calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Installation structure diagram.

[0016] Figure 2 The flowchart of the method is shown in FIG.

[0017] In the figure: 1 test block, 2 probe positioning device, 3 probe, L test block length, W test block width, H test block thickness. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The front of the ultrasonic surface wave instrument is equipped with a flaw detection machine interface and button distribution, which adopts key adjustment settings and has a display screen.

[0020] It includes a microprocessor, a transmitting circuit, a receiving circuit and a sensor. The transmitting circuit transmits the data commands processed by the microprocessor to the receiving circuit. It also includes a power supply, a display and an A / D converter. The power supply provides power to the microprocessor and the transmitting circuit, the display controls the display status of the circuit equipment, and the A / D converter works by converting the signal receiving circuit and the microprocessor.

[0021] It has a software system inside to control the image display and use key operation programs.

[0022] First, prepare the test blocks used;

[0023] like Figure 1 As shown, the test block is a rectangular parallelepiped structure with three-dimensional size parameters of length (L) ≥ 50 mm, width (W) ≥ 50 mm, and thickness (H) ≥ 10 mm. A probe positioning device is provided on the upper surface of the test block.

[0024] The probe positioning device is a strip-shaped protrusion along the length direction. The strip-shaped protrusion extends along the length direction and has a rectangular cross-section. The side of the strip-shaped protrusion is perpendicular to the upper surface of the test block. The side of the strip-shaped protrusion is used to cooperate with the side of the probe to position the probe.

[0025] The strip-shaped protrusion is approximately located in the middle of the width direction.

[0026] When the probe is placed on the upper surface of the test block, the side surface of the probe and the side surface of the positioning device on the test block are closely fitted to each other.

[0027] The test block materials are divided into high-quality carbon steel, martensitic steel and austenitic steel.

[0028] A method for calibrating zero bias and front edge of ultrasonic surface wave probe and sound velocity

[0029] It has the following steps:

[0030] (1) Preparation and selection of test blocks

[0031] The test blocks are made of high-quality carbon steel, martensitic steel or austenitic steel;

[0032] Select a test block with a material similar to that of the workpiece to be tested by the probe;

[0033] (2) Position the probe to be tested

[0034] Place the probe to be tested on the upper surface of the test block, with the side of the probe and the side of the positioning device on the test block tightly fitting each other;

[0035] (3) Initial reset

[0036] The zero bias parameter and the leading edge parameter of the instrument driving the probe to transmit and receive the ultrasonic surface wave are reset to zero, the zero bias parameter and the leading edge parameter on the instrument keyboard are adjusted to 0 by pressing the buttons, and the instrument is adjusted to the self-transmitting and self-receiving mode;

[0037] (4) Determine the zero bias parameters

[0038] Move the probe along the positioning device, and observe the amplitude and position changes of the upper corner echo of the test block through the display screen. When the upper corner echo signal moves forward and gradually decreases, continue to move the probe in this direction until the upper corner echo signal disappears completely, and record the echo time t0 of the last stage before the upper corner signal disappears; the t0 value is used as the zero bias parameter of the surface wave probe to be tested;

[0039] (5) Determine the frontier parameters

[0040] Move the probe along the positioning device until the front edge of the probe is flush with the side surface of the test block (side surface of width W), and read the echo time t1 at the upper corner of the test block, the first echo time t2 at the lower corner, and the second echo time t3 at the lower corner; the t1 value is used as the front edge parameter of the probe to be tested;

[0041] (6) Input the values ​​of t0 and t1 into the ultrasonic instrument through the key, the t0 value is used as the zero bias parameter of the surface wave probe to be measured, and the t1 value is used as the front parameter of the surface wave probe to be measured;

[0042] (7) Calculate and calibrate the sound velocity values ​​v1 = H / (t2-t1) / 2, v2 = H / (t3-t2) / 2, v = (v1+v2) / 2, where H is the thickness of the specimen; input the v value into the ultrasonic instrument by pressing the key.

[0043] By inputting the calibrated zero bias parameters, front parameters and sound velocity value v into the instrument that drives the probe to transmit and receive ultrasonic surface waves, the position of the reflected wave can be accurately obtained according to the displayed position of the reflected wave in the instrument in subsequent detection.

[0044] Finally, it should be noted that the above description is only an explanation of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail, those skilled in the art can still modify the technical solutions described above or replace some of the technical features with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for calibrating zero bias, front edge and sound velocity of an ultrasonic surface wave probe, characterized in that: The steps are as follows: Step 1) preparing and selecting test blocks; Step 2) positioning the probe to be tested; Step 3) Initial reset, zero bias parameters and leading edge parameters are all reset to zero; Step 4) the probe is translated, and the echo time in the last stage before the upper corner signal disappears is determined as the zero bias parameter; Step 5) Move the probe until the front edge of the probe is flush with the side of the test block, and the echo time at the upper corner of the test block is determined as the front edge parameter; Step 6) Calculate and calibrate the sound velocity value using the first echo time at the lower corner and the second echo time at the lower corner.

2. The method for calibrating zero bias, front edge and sound velocity of an ultrasonic surface wave probe according to claim 1, characterized in that , In step 1), the test block is made of high-quality carbon steel, martensitic steel or austenitic steel; and the test block is selected to have a material close to that of the workpiece to be detected by the probe to be tested.

3. The method for calibrating the zero bias, front edge and sound velocity of an ultrasonic surface wave probe according to claim 1, characterized in that ,In step 1), the test block is a rectangular parallelepiped structure, and a probe positioning device is provided on the upper surface of the test block; The probe positioning device is a strip-shaped protrusion along the length direction. The strip-shaped protrusion extends along the length direction. The side of the strip-shaped protrusion is perpendicular to the upper surface of the test block. The side of the strip-shaped protrusion is used to cooperate with the side of the probe to position the probe.

4. The method for calibrating zero bias, front edge and sound velocity of an ultrasonic surface wave probe according to claim 3, characterized in that ,In step 2), the probe to be tested is placed on the upper surface of the test block, and the side of the probe and the side of the positioning device on the test block are tightly fitted to each other.

5. The method for calibrating zero bias, front edge and sound velocity of an ultrasonic surface wave probe according to claim 4, characterized in that In step 4), the probe is translated along the positioning device, and the amplitude and position changes of the upper corner echo of the test block are observed through the display screen. When the upper corner echo signal moves forward and gradually decreases, the probe continues to be moved in this direction until the upper corner echo signal completely disappears.

6. A method for calibrating zero bias, front edge and sound velocity of an ultrasonic surface wave probe according to claim 4, characterized in that ,In step 5), move the probe along the positioning device until the front edge of the probe is flush with the side of the test block, and read the echo time t1 at the upper corner of the test block.

7. A method for calibrating zero bias, front edge and sound velocity of an ultrasonic surface wave probe according to claim 6, characterized in that ,In step 5), the probe is moved along the positioning device until the front edge of the probe is flush with the side of the test block, and the first echo time t2 at the lower corner and the second echo time t3 at the lower corner are also read.

8. A method for calibrating zero bias, front edge and sound velocity of an ultrasonic surface wave probe according to claim 7, characterized in that ,In step 6), calculate and calibrate the sound velocity values ​​v1=H / (t2-t1) / 2, v2=H / (t3-t2) / 2, v=(v1+v2) / 2, and H is the specimen thickness.

9. A method for calibrating zero bias, front edge and sound velocity of an ultrasonic surface wave probe according to claim 8, characterized in that , input the calibrated zero bias parameters, frontier parameters and sound velocity value v into the instrument.

10. A method for calibrating zero bias, front edge and sound velocity of an ultrasonic surface wave probe according to claim 8, characterized in that ,In step 2), adjust the instrument to the self-transmitting and self-receiving mode.

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