JPH01145529A - Ultrasonic measuring apparatus - Google Patents

Abstract

PURPOSE:To precisely measure the propagation speed of an ultrasonic wave by removing the measuring error caused by the change of the circumferential temp., by providing a temp. compensating vibrator in the case of a probe apart from transmitting and receiving vibrators. CONSTITUTION:A temp. compensating vibrator 11 is provided in the case 3 of a probe P apart from vibrators 1, 2. The vibrator 11 is arranged in opposed relation to the surface 4a of test specimen 4 so as to provide a definite know interval to transmit and receive an ultrasonic wave with respect to the surface 4a. A transmitting part 12 applies transmission voltage to the vibrator 11 and a receiving part 13 receives signal voltage generated when the vibrator 11 receives the reflected wave from the surface 4a. A control part 14 is respectively connected to transmitting parts 6, 13 and receiving parts 6, 13, and the propagation time of the ultrasonic wave transmitted and received between the vibrators 1, 2 and that of the ultrasonic wave transmitted and received between the vibrator 11 and the surface 4a are separately operated to measure the propagation time of the ultrasonic wave propagating through the test specimen 4. By this method, the measuring error due to the change of circumferential temp. is compensated and the propagation speed of an ultrasonic wave can be precisely measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ultrasonic measuring device that measures the propagation speed of ultrasonic waves, and particularly to a measuring device suitable for precisely measuring the propagation speed.

[Prior Art] Ultrasonic waves, which are widely and frequently used in non-destructive testing, are applied not only to detecting defects inside objects but also to various other uses by utilizing their properties. Among these applications, measurements are often made using the propagation velocity or propagation time of ultrasonic waves propagating inside the specimen. Specific examples include measuring internal stress in steel materials, etc., and nodularity of graphite in cast iron. In addition to calculating the thickness of objects, measuring the thickness of objects, etc., it also measures the depth of quenching due to heat treatment of steel materials, etc. In order to improve the measurement accuracy in each of these measurements, it is necessary to accurately measure the propagation velocity or propagation time of ultrasonic waves. As a specific example, in the case of measuring the quenching depth, the propagation speed of ultrasonic waves in the quenching layer has the property of becoming slower as the quenching depth increases, and by measuring the propagation speed, the quenching depth can be determined. However, the correlation between quenching depth and propagation velocity is generally small, with a change in propagation velocity of about 1% per 1 m of quenching depth, and therefore it is difficult to capture changes in propagation velocity unless the propagation velocity is precisely measured. becomes coarser, making it impossible to accurately measure the hardening depth.

A general configuration example of a conventional measuring device for measuring the propagation velocity will be explained with reference to FIG. 2. In the figure, 1 is a transmitting transducer, 2 is a receiving transducer, and transducers 1 and 2 are case 3.
The transducers 1 and 2 and the case 3 constitute the probe P0 as main components. 4 is the object to be inspected, and 4a is the surface (flaw detection surface) of the object 4 to be inspected. 5 is a transmitter that applies a transmission voltage to the vibrator 1; 6 is a receiver that receives the signal voltage received by the vibrator 2; 7 is connected to the transmitter 5 and the receiver 6, and is connected between the vibrators 1 and 2. This is a control unit that calculates the propagation time of transmitted and received ultrasonic waves. In the above configuration, when a transmission voltage is applied to the transducer 1 from the transmitter 5, an ultrasonic wave is emitted from the transducer 1 in the direction shown in the figure.

The emitted ultrasound waves strike the surface 4a of the subject 4 at a predetermined angle.
When the wave reaches the object 4, the mode is converted from longitudinal wave to transverse wave.
and propagates through the surface layer of the subject 4. After propagating a certain distance, the mode is converted from a transverse wave to a longitudinal wave again, and the wave is emitted from the surface 4a at a predetermined angle and received by the vibrator 2. The signal voltage received by the transducer 2 is sent to the receiving section 6, and further sent to the control section 7, where the propagation time of the ultrasonic waves transmitted and received between the transducers 1 and 2 is measured. In this case, vibrator 1
, the propagation distance of the ultrasonic waves transmitted and received between the probe P. Since the distance of propagation through the surface layer of the subject 4 is known from the dimensions of each part, the propagation speed corresponding to the propagation time is easily calculated by the control unit 7.

However, in the above measurement, the ambient temperature of the measuring device is not always constant and usually varies considerably depending on not only the air temperature but also the temperature of the measurer's hand. Receiving section 6. Even when using the control unit 7,
Probe P. Since the characteristics with respect to temperature changes are so large that they cannot be ignored, this results in an error in the measured value. -For example, the change in the sound speed of ultrasonic waves in steel is negligibly small, about 0.01% for a temperature change of 10°C, but the sound speed in the probe P0 is small because a wedge-shaped synthetic resin is used. A temperature change of 10° C. causes a change in the sound speed of an ultrasonic wave of about 1%, which is the main cause of measurement errors and poses a problem in that the propagation speed cannot be precisely measured.

[Problems to be Solved by the Invention] In view of the above problems, the present invention provides an ultrasonic measurement device that can eliminate measurement errors due to changes in ambient temperature and accurately measure the propagation speed of ultrasonic waves. The purpose is to

[Means for Solving the Problems] - In order to achieve this objective, the ultrasonic measuring device of the present invention includes a transmitting transducer and an ultrasonic wave emitted from the transducer in the same case. a probe disposed opposite to a receiving transducer that receives waves through the transmitting transducer; a transmitter that applies a transmission voltage to the transmitting transducer; and a signal received by the receiving transducer. An ultrasonic measuring device comprising: a receiving section that receives a voltage; and a control section that is connected to the transmitting section and the receiving section and calculates the propagation time of ultrasonic waves transmitted and received between the transmitting and receiving transducers. In addition to the transmitting and receiving transducers, a temperature-compensating transducer for transmitting and receiving ultrasonic waves at regular intervals is housed inside the case of the probe, and the transducer transmits and receives the transducer. The method is characterized in that the propagation time of the transmitted ultrasonic waves is calculated separately from the propagation time of the ultrasonic waves transmitted and received by the transmitting and receiving planar transducers, and the propagation time of the transmitted ultrasonic waves through the object is measured. .

[Example] Hereinafter, an example of the present invention will be described with reference to FIG. In the figure, the same reference numerals as in FIG. 2 indicate the same thing. In the figure, reference numeral 11 denotes a temperature-compensating vibrator installed inside the case 3 separately from the vibrators 1 and 2. It serves as a transducer for transmitting and receiving ultrasonic waves to and from one surface 4a.

The probe P has a vibrator 11 added to the probe P0 shown in FIG. 2. 12 is the vibrator 11
13 is a receiving section that receives the signal voltage obtained by the vibrator 11 receiving the reflected wave from the surface 4a, and 14 is connected to the transmitting sections 5, 12 and the receiving section 6.13, respectively. , transducer 1 and 2 questions and transducer 11 and surface 4
This is a control unit that calculates each propagation time of ultrasonic waves transmitted and received between the two.

In the embodiment with the above configuration, the propagation time of the ultrasonic waves between the transducers 1 and 2 is measured in the same manner as described in the conventional art shown in FIG. That is, the time t1 for the ultrasonic wave to propagate a set known distance of the object 4 from the incident point to the emission point on the surface 4a of the object 4, and the ultrasonic wave emitted from the transducer 1 received by the transducer 2. The total time t0 including the time t for propagation within the probe P until being waved is measured.

On the other hand, the ultrasonic waves emitted from the transducer 11 in response to the signal from the transmitter 12 reach the surface 4a of the subject 4, and
The reflected wave reflected by a is received by the vibrator 11 and sent to the receiver 13
It is sent to the control unit 14 via. The control unit 14 determines the propagation time t of the ultrasonic waves transmitted and received between the transducer 11 and the surface 4a.
, is measured. Time t and t3 among the measured propagation times are both propagation times within the probe P, and can be expressed as in the following equation.

t2=kt3 (1) Here, k is a constant determined by the structure and dimensions of the probe P, and is unrelated to the ambient temperature at the time of measurement. In addition, the propagation time to” (t1+
jt) and t, and the relationship with the above formula (1), the following formula is obtained.

t□=to-kt3 ・・・・・・(2)
Therefore, using equation (2), the propagation time ti through the object 4 is
Measurement errors due to changes in ambient temperature can be compensated for and measurements can be made accurately and easily without being affected by the temperature, and at the same time, the propagation velocity with respect to time t is calculated. Conventionally, this has been done through measures to keep the ambient temperature constant, such as immersing the subject and probe in a thermostatic water tank containing water at a constant temperature, or setting up a constant temperature room and performing measurements inside the room. It also has the effect of being freed from the hassle and allowing measurements to be taken regardless of the ambient temperature at the production site.

In the above embodiment, the vibrator 11 was used for both transmission and reception, but
Separate this into transmitter and receiver, case 3 of probe P.
The structure may be such that they are arranged facing each other inside. in this case,
The opposing positions may be arbitrary, as long as they can transmit and receive ultrasonic waves at known constant intervals, but the measuring time t0
It is preferable to arrange the values of t3 and t3 to be different values so that they can be clearly distinguished. This also applies when the vibrator 11 is used for both transmission and reception. In consideration of the arrangement of each transducer, the transmitting section 5 and receiving section 6 for the transducers 1 and 2, and the transmitting section 12 and receiving section 13 for the transducer 11 are arranged as shown in FIG. 1 of this embodiment. If they are provided separately as shown in the figure, the time toy t3 is measured separately, so it is not so necessary; Therefore, in that case, it is necessary to distinguish and measure times t0 and t3. When the transmitting section 5 and the receiving section 6 are used also as a vibrator for temperature compensation, the transmitting section 1
2 and the receiving section 13 are no longer required, which has the effect of simplifying the device.

Note that if the control unit 14 is provided with a display unit, a recording unit, etc. that displays the measured propagation time and its speed, or is connected to the outside, it becomes possible to easily measure the negative layer.

The precise measurement of the ultrasonic propagation speed described above can also be applied to the measurement of the hardening depth mentioned above as a specific example, and it goes without saying that the hardening depth can be measured accurately and easily. It is.

[Effects of the Invention] As described above, the ultrasonic measuring device according to the present invention has transducers for transmitting and receiving in the case of the probe, and transmits and receives ultrasonic waves at regular intervals within the case. A temperature-compensating transducer is installed inside, and the propagation time of the ultrasonic waves transmitted and received by the transducer is calculated separately from the propagation time of the ultrasonic waves transmitted and received by the transmitting and receiving surface transducers. Since the configuration is configured to measure the propagation time of the specimen, measurement errors due to changes in ambient temperature can be removed, and the propagation speed of the ultrasonic wave can be precisely measured, which is a significant practical effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an ultrasonic measuring device according to the present invention. FIG. 2 is a block diagram showing a general configuration example of a conventional device. Patent Applicant Hitachi Construction Machinery Co., Ltd. Agent Patent Attorney Masami Akimoto (1 other person) = 7 = 2 Tsuyoshi Iwo Shop P Uke Ihata Roshi? & sa 2゜4a

Claims (1)

[Claims] 1. A probe in which a transmitting transducer and a receiving transducer that receives ultrasonic waves emitted from the transducer through a subject are placed opposite each other in the same case. a transmitter that applies a transmission voltage to the transmitting transducer; a receiving section that receives the signal voltage received by the receiving transducer; and a transmitter that is connected to the transmitter and the receiver. In an ultrasonic measurement device comprising a control unit that calculates the propagation time of ultrasonic waves transmitted and received between both transducers for transmission and reception, each of the vibrations for transmission and reception is placed in the case of the probe. Separately from the transducer, a temperature-compensating transducer for transmitting and receiving ultrasonic waves at regular intervals is installed inside the case, and the propagation time of the ultrasonic waves transmitted and received by the transducer is determined by the transmission and reception transducers. An ultrasonic measuring device characterized in that the ultrasonic measuring device is configured to calculate the propagation time of ultrasonic waves transmitted and received separately and measure the propagation time of the ultrasonic waves propagating through the object. 2. The ultrasonic measuring device according to claim 1, wherein the temperature compensating vibrator is separated into a transmitting and receiving vibrator and disposed facing each other in the probe case. 3. Place each transducer at a position where the propagation time of the ultrasonic waves transmitted and received by the temperature compensation transducer and the propagation time of the ultrasonic waves transmitted and received by both the transmitting and receiving transducers can be determined. An ultrasonic measuring device according to claim 1, which is configured to be placed in a. 4. The ultrasonic measuring device according to claim 1, wherein the transmitter is configured to have separate transducers for the transmitting and receiving transducers and a temperature compensating transducer. 5. The ultrasonic measuring device according to claim 1, wherein the receiving section is configured to separately provide transducers for the transmitting and receiving transducers and a transducer for temperature compensation.