CN106441178A - Ultrasonic thickness measuring technology having self-correcting function - Google Patents

Ultrasonic thickness measuring technology having self-correcting function Download PDF

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CN106441178A
CN106441178A CN201610974406.9A CN201610974406A CN106441178A CN 106441178 A CN106441178 A CN 106441178A CN 201610974406 A CN201610974406 A CN 201610974406A CN 106441178 A CN106441178 A CN 106441178A
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ultrasonic
thickness
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probe
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甘芳吉
廖俊必
万正军
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Sichuan University
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01BMEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B17/00Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
    • G01B17/02Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations for measuring thickness

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  • General Physics & Mathematics (AREA)
  • Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)

Abstract

本发明涉及一种具有自校正功能的超声波测厚技术。传统的超声波测厚技术是检测超声波在被测件中的飞跃时间T,然后利用超声波的声速V,利用D=VT/2即可求出被测件的厚度。然而不同的被测材料,或者随着被测件温度的变化,超声波在被测件中的传播速度会发生改变,如果不加以修正就会引起很大的测量误差。本发明提出的自校正超声波测厚技术,设置一个超声波探头(3)同时作为超声波发射端也超声波接收端,在超声波探头(3)与被测件(1)之间引入一个已知厚度的校正块(2),校正块(2)的材料与被测件(1)的材料一致,通过测量超声波在校正块(2)中的飞跃时间以及超声波在被测件(1)中的飞跃时间,即可求出被测件的厚度,起到了自校正的功能。

The invention relates to an ultrasonic thickness measurement technology with self-correction function. The traditional ultrasonic thickness measurement technology is to detect the flight time T of the ultrasonic wave in the tested piece, and then use the sound velocity V of the ultrasonic wave to calculate the thickness of the tested piece by using D=VT/2 . However, with different materials to be tested, or as the temperature of the tested piece changes, the propagation speed of the ultrasonic wave in the tested piece will change, and if it is not corrected, it will cause a large measurement error. The self-calibration ultrasonic thickness measurement technology proposed by the present invention sets an ultrasonic probe (3) as the ultrasonic transmitting end and ultrasonic receiving end at the same time, and introduces a correction of known thickness between the ultrasonic probe (3) and the measured piece (1). block (2), the material of the calibration block (2) is consistent with the material of the test piece (1), by measuring the flight time of the ultrasonic wave in the correction block (2) and the flight time of the ultrasonic wave in the test piece (1), The thickness of the measured piece can be obtained, and it has the function of self-calibration.

Description

一种具有自校正功能的超声波测厚技术An Ultrasonic Thickness Measuring Technology with Self-Correcting Function

技术领域technical field

本发明主要用于测厚,可用于管道、容器壁厚检测,也可用于金属件内部探伤等。The invention is mainly used for thickness measurement, can be used for pipe and container wall thickness detection, and can also be used for internal flaw detection of metal parts and the like.

背景技术Background technique

目前很多行业都需要对工件、设备等进行厚度测量,或者对内部进行探伤等。超声波测厚技术是一种常用的测厚技术,其技术的原理如下:At present, many industries need to measure the thickness of workpieces and equipment, or perform internal flaw detection. Ultrasonic thickness measurement technology is a commonly used thickness measurement technology, and its technical principle is as follows:

1、将超声波探头安装在被测件表面,利用超声波探头激发出超声波,使超声波在被测件中传播,当超声波遇到被测件底面时就会有部分超声波反射回来并被超声波探头所接收,测量出超声波在被测件中的传播时间T,然后利用超声波的声速V,即可计算出被测件的厚度,公式如下:1. Install the ultrasonic probe on the surface of the tested part, use the ultrasonic probe to excite the ultrasonic wave, so that the ultrasonic wave propagates in the tested part, when the ultrasonic wave meets the bottom surface of the tested part, part of the ultrasonic wave will be reflected back and received by the ultrasonic probe , measure the propagation time T of the ultrasonic wave in the tested piece, and then use the sound velocity V of the ultrasonic wave to calculate the thickness of the tested piece, the formula is as follows:

D=VT/2D=VT/2

公式中的D代表被测件的厚度。D in the formula represents the thickness of the tested piece.

由这个公式可以知道,为了准确测量得到被测件的厚度,需要准确知道超声波在被测件中的传播时间T,同时也必须准确知道超声波的声速V。当前的技术可以非常准确地测量出超声波的传播时间,但是超声波在不同的材料中的传播速度是不一样的,而且温度的变化也会改变超声波的声速,目前传统的超声波测厚仪都采用一个统一的超声波声速来计算被测件的厚度,无法校正由于声速改变引起的测量误差。显然传统的超声波测厚技术非常容易受到干扰,精度难以保证。It can be known from this formula that in order to accurately measure the thickness of the tested part, it is necessary to accurately know the propagation time T of the ultrasonic wave in the tested part, and at the same time, the sound velocity V of the ultrasonic wave must be accurately known. The current technology can measure the propagation time of ultrasonic waves very accurately, but the propagation speed of ultrasonic waves in different materials is different, and the change of temperature will also change the sound speed of ultrasonic waves. At present, traditional ultrasonic thickness gauges use a The uniform ultrasonic sound velocity is used to calculate the thickness of the tested part, and the measurement error caused by the change of sound velocity cannot be corrected. Obviously, the traditional ultrasonic thickness measurement technology is very susceptible to interference, and the accuracy is difficult to guarantee.

本专利旨在提出一种带有自校正功能的超声波测厚技术,能够有效消除声速变化对测量造成的影响。This patent aims to propose an ultrasonic thickness measurement technology with self-correction function, which can effectively eliminate the influence of sound velocity changes on measurement.

发明内容Contents of the invention

本专利主要是针对目前传统的超声波测厚技术需要将超声波的声速纳入壁厚计算,检测结果容易受到外界因素影响这一问题,提出了一种具有自校正功能的超声波测厚技术。This patent is mainly aimed at the problem that the current traditional ultrasonic thickness measurement technology needs to incorporate the sound velocity of ultrasound into the wall thickness calculation, and the detection results are easily affected by external factors. An ultrasonic thickness measurement technology with self-correction function is proposed.

为了消除声速变化对超声波测厚带来的影响,本发明中创新性地引入了一个校正块。该校正块的材料与被测件的材料一致,校正块的厚度可以精确测量得到,命名为D 1 。校正块的上端面固定安装一个超声波探头,同时作为超声波激励端以及超声波接收端。对被测件进行测量时,将校正块的下表面通过耦合剂与被测件接触,使超声波能够更多地传播进入被测件。超声波探头激发出超声波,与此同时系统开始计算超声波的传播时间。激发的超声波首先在校正块里传播,当超声波碰到校正块的下表面时,一部分超声波会反射回来被超声波探头所接收到,并记录下信号接收时间,将该时间命名为T 1 ;一部分超声波会发生透射,然后进入被测件继续传播,当这部分超声波碰到被测件底部时,又有一部分超声波反射回来,并最终被超声波探头所接收,同样记录下信号接收时间,将该时间命名为T 2 。此时,利用下面的公式即可求出被测件的厚度:In order to eliminate the influence of the change of sound velocity on the ultrasonic thickness measurement, a correction block is innovatively introduced in the present invention. The material of the calibration block is the same as that of the tested piece, and the thickness of the calibration block can be accurately measured, which is named D 1 . An ultrasonic probe is fixedly installed on the upper end surface of the correction block, which serves as an ultrasonic excitation end and an ultrasonic receiving end at the same time. When measuring the tested part, the lower surface of the calibration block is contacted with the tested part through the coupling agent, so that the ultrasonic wave can propagate more into the tested part. The ultrasonic probe excites ultrasonic waves, and at the same time the system begins to calculate the propagation time of the ultrasonic waves. The excited ultrasonic wave first propagates in the calibration block. When the ultrasonic wave hits the lower surface of the calibration block, a part of the ultrasonic wave will be reflected back and received by the ultrasonic probe, and record the signal receiving time, which is named as T 1 ; a part of the ultrasonic wave Transmission will occur, and then enter the tested part to continue to propagate. When this part of the ultrasonic wave hits the bottom of the tested part, another part of the ultrasonic wave will be reflected back and finally received by the ultrasonic probe. Also record the signal receiving time and name the time for T 2 . At this point, use the following formula to find the thickness of the tested piece:

DD. 22 =D=D 11 (T(T 22 -T-T 11 )/T)/T 11

式中,T 1 为超声波探头接收到校正块反射波的时间;T 2 为超声波探头接收到被测件反射波的时间;D 1 为校正块的厚度,D 2 为被测件的厚度。 In the formula, T1 is the time when the ultrasonic probe receives the reflected wave from the calibration block ; T2 is the time when the ultrasonic probe receives the reflected wave from the measured piece ; D1 is the thickness of the calibration block, and D2 is the thickness of the tested piece.

该公式只需准确测量出校正块的厚度、以及超声波在校正块和被测件中的穿行时间即可求出被测件的厚度,不包含声速,也即是该方法避免了超声波声速变化对测量造成的影响,达到了自校正的目的。This formula only needs to accurately measure the thickness of the calibration block and the travel time of the ultrasonic waves in the calibration block and the measured object to obtain the thickness of the measured object, excluding the speed of sound, that is, this method avoids the impact of changes in the ultrasonic sound velocity. The influence caused by the measurement achieves the purpose of self-calibration.

本发明的有益效果:利用超声波技术测厚时,当超声波声速发生了改变,校正块可以有效消除掉声速变化的影响,保证了检测精度。The beneficial effect of the present invention is that when ultrasonic technology is used for thickness measurement, when the ultrasonic sound velocity changes, the correction block can effectively eliminate the influence of the change of sound velocity, thereby ensuring the detection accuracy.

附图说明Description of drawings

图1 自校正超声波测厚技术原理Figure 1 Principle of self-correcting ultrasonic thickness measurement technology

图2 自校正超声波测厚技术接收反射超声波时间Figure 2 The time of receiving reflected ultrasonic wave by self-calibration ultrasonic thickness measurement technology

图3 超声波在校正块里的穿越时间Figure 3 Transit time of ultrasound in the calibration block

图4 超声波在校正块和被测件中的穿越时间。Figure 4 Transit time of ultrasonic waves in the calibration block and the DUT.

具体实施方式detailed description

本发明的一个实施例详述如下:An embodiment of the invention is described in detail as follows:

本发明是一种具有自校正功能的超声波测厚技术,具体实施步骤如下:The present invention is an ultrasonic thickness measurement technology with self-correcting function, and the specific implementation steps are as follows:

(1)选取一块厚度为10mm的金属平板作为被测对象,该金属平板的材料为20号碳钢。选用20号碳钢加工了一个校正块,该校正块的形状为圆柱形,直径为10mm,厚度为25mm。(1) Select a metal plate with a thickness of 10mm as the object to be tested, and the material of the metal plate is No. 20 carbon steel. A correction block is processed by using No. 20 carbon steel. The shape of the correction block is cylindrical, the diameter is 10mm, and the thickness is 25mm.

(2)将一超声波探头对称固定安装在校正块的上端面。(2) Install an ultrasonic probe symmetrically and fixedly on the upper end surface of the calibration block.

(3)在校正块的下表面涂抹耦合剂,用于测量金属平板的厚度。(3) Apply couplant on the lower surface of the calibration block to measure the thickness of the metal plate.

(4)利用加热器加热被测金属平板,用于改变超声波在金属平板中的传播速度,同时由于热传递效应,校正块也同时被加热了,两者的温度一致。(4) Use the heater to heat the tested metal plate to change the propagation speed of the ultrasonic wave in the metal plate. At the same time, due to the heat transfer effect, the calibration block is also heated at the same time, and the temperature of the two is the same.

(5)利用本发明中设计的自校正超声波测厚系统和普通的超声波测厚系统分别测量不同温度下的金属平板,测量结果如下:(5) Use the self-correcting ultrasonic thickness measuring system designed in the present invention and the ordinary ultrasonic thickness measuring system to measure metal plates at different temperatures, and the measurement results are as follows:

注:壁厚1为自校正超声波测厚系统的检测结果,壁厚2为传统超声波测厚系统的检测结果。可见,由于温度改变了超声波在被测件中的传播速度,传统的超声波测厚技术的检测精度很低,但是本发明提出的自校正超声波测厚系统则有效消除了超声波声速变化的影响,保持了很好了检测精度。Note: Wall thickness 1 is the test result of the self-correcting ultrasonic thickness measurement system, and wall thickness 2 is the test result of the traditional ultrasonic thickness measurement system. It can be seen that the detection accuracy of the traditional ultrasonic thickness measurement technology is very low because the temperature changes the propagation speed of the ultrasonic wave in the tested piece, but the self-correcting ultrasonic thickness measurement system proposed by the present invention effectively eliminates the influence of the change of the ultrasonic sound velocity and maintains The detection accuracy is very good.

Claims (2)

1.一种带有自校正功能的超声波测厚技术,其特征在于:目前的超声波测厚系统的工作原理是测量超声波在被测件中的飞跃时间T,再利用超声波的声速V计算得到被测件的厚度D,即D=V×T/2;但是温度变化、材料不同等都会造成超声波声速的改变,进而造成测量误差;本专利提出的技术方案是自校正法,具体是在超声波测量回路中引入一个校正块,利用该校正块自动消除声速变化对测量造成的影响;具体步骤如下:1. An ultrasonic thickness measurement technology with self-calibration function, characterized in that: the working principle of the current ultrasonic thickness measurement system is to measure the flight time T of the ultrasonic wave in the measured piece, and then calculate the measured value by using the sound velocity V of the ultrasonic wave. The thickness D of the test piece, that is, D = V × T /2; however, temperature changes and different materials will cause changes in the ultrasonic sound velocity, which in turn will cause measurement errors; the technical solution proposed in this patent is a self-correction method, specifically in ultrasonic measurement Introduce a correction block into the circuit, and use this correction block to automatically eliminate the influence of sound velocity changes on the measurement; the specific steps are as follows: (1)采用一个超声波探头,同时作为超声波激励探头以及超声波接收探头;(1) An ultrasonic probe is used as an ultrasonic excitation probe and an ultrasonic receiving probe; (2)在探头与被测件之间引入一个校正块,精确测量并记录该校正块的厚度,命名为D 1 ,该校准块的材料与被测件的材料一致;(2) Introduce a calibration block between the probe and the tested piece, accurately measure and record the thickness of the calibration block, named D 1 , and the material of the calibration block is consistent with the material of the tested piece; (3)测量并记录超声波从开始激发到从校正块底部反射并被超声波探头所接收的时间,命名为T 1 (3) Measure and record the time from the start of ultrasonic excitation to the reflection from the bottom of the calibration block and reception by the ultrasonic probe, which is named as T 1 ; (4)测量并记录超声波从开始激发到从被测件底部反射并被超声波探头所接收的时间,命名为T 2 (4) Measure and record the time from when the ultrasonic wave is excited to when it is reflected from the bottom of the test piece and received by the ultrasonic probe, which is named as T 2 ; (5)利用下面的公式即可计算得到被测件的厚度D 2 (5) The thickness D 2 of the tested piece can be calculated by using the following formula: D 2 =D 1 ×(T 2 - T 1 )/T 1 D 2 = D 1 × ( T 2 - T 1 )/ T 1 步骤(5)的公式中不包含声速V,因此可以有效消除声速改变对测量造成的影响。The formula of step (5) does not include the speed of sound V , so the influence of the change of sound speed on the measurement can be effectively eliminated. 2.根据权利点1,校正块的厚度一般大于20mm,其形状可以为圆柱体,也可以为立方体。2. According to claim 1, the thickness of the correction block is generally greater than 20mm, and its shape can be a cylinder or a cube.
CN201610974406.9A 2016-11-07 2016-11-07 Ultrasonic thickness measuring technology having self-correcting function Pending CN106441178A (en)

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CN115638751A (en) * 2021-07-20 2023-01-24 中国石油化工股份有限公司 Detection system and detection method for pipeline wall thickness

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