JP2015206782A - Residual stress evaluation method and residual stress evaluation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a residual stress evaluation method and a residual stress evaluation device which can accurately measure the residual stress on a surface layer of an inspection object body by suppressing deterioration of measurement accuracy due to the contact state of an ultrasonic probe to the inspection object body with a relatively simple configuration.SOLUTION: A residual stress evaluation device which evaluates the residual stress existing on a surface layer of a measurement sample W on the basis of the propagation time of the ultrasonic wave propagating on the surface layer of the measurement sample W, comprises: a transmission probe which transmits an SH wave and an SV wave with different vibration forms to the surface layer of the measurement sample W to excite a Rayleigh wave and a surface SH wave as a plurality of propagation ultrasonic waves with different vibration forms on the surface layer of the measurement sample W; a reception probe which receives the propagation ultrasonic waves with different vibration forms propagating on the surface layer of the measurement sample W; and an evaluation unit which calculates each propagation time of the plurality of kinds of propagation ultrasonic waves received by the reception probe to evaluate the residual stress existing on the surface layer of the measurement sample W on the basis of the calculated propagation time.

Description

  The present invention relates to a residual stress evaluation method and a residual stress evaluation apparatus for evaluating a residual stress existing on a surface layer of a sample to be inspected, such as a metal material, based on a sound velocity of an ultrasonic wave propagating through the surface layer of the sample to be inspected.

Measurement of non-destructive residual stresses of various machine parts and structures is extremely important for deterioration diagnosis of these parts and structures. Conventionally, the X-ray diffraction method has been mainly used for the measurement (evaluation) of non-destructive residual stress. However, in the X-ray diffraction method, an extremely shallow region of the surface layer of the object to be inspected is used. There is a restriction that only (˜several μm) can be evaluated.
Therefore, ultrasonic stress measuring devices and ultrasonic stress measuring methods disclosed in Patent Documents 1 and 2 are proposed as residual stress evaluation means (acoustic elasticity method) using ultrasonic waves that can eliminate these restrictions and concerns. Has been.

  The ultrasonic stress measuring device disclosed in Patent Document 1 is ultrasonic data obtained when longitudinal wave ultrasonic waves and two transverse wave ultrasonic waves whose vibration directions are orthogonal to each other propagate through the stress measurement target material. Is an ultrasonic stress measurement device for analyzing the residual stress of the material to be stress-measured, and is arranged around a longitudinal wave probe P0 that transmits and receives the longitudinal wave ultrasonic waves. First and second horizontal transverse wave probes P1, P2 that transmit and receive transverse wave ultrasonic waves having a horizontal vibration direction are arranged on both sides in the horizontal direction of the probe P0, and the longitudinal wave probe P0. A probe assembly comprising first and second vertical transverse wave probes P3 and P4 for transmitting and receiving transverse wave ultrasonic waves whose vibration directions are perpendicular to each other on both sides of the vertical direction, and the probe An ultrasonic transmission / reception control unit for performing ultrasonic transmission / reception control on each probe of the assembly; A measurement data analysis unit that inputs ultrasonic data of each probe from the ultrasonic transmission / reception control unit, obtains sound velocity data of each ultrasonic wave, and analyzes the residual stress of the stress measurement target material; It is characterized by that.

  In addition, an ultrasonic stress measuring device disclosed in Patent Document 2 includes a longitudinal wave ultrasonic probe and a transverse wave ultrasonic probe that can be disposed on the surface of a stress measurement target material, and both the probes. A probe driving mechanism capable of moving or rotating along the surface of the material, and transmitting and receiving ultrasonic waves to and from the measurement target portion of the material on one of the probes. After that, the arrangement of one probe and the other probe is switched by controlling the movement with respect to the probe driving mechanism, and the other probe transmits ultrasonic waves to the same measurement target part. The reception operation is performed, and the transverse wave ultrasonic probe is rotated N times for each rotation angle of 180 ° / N (N: integer of 2 or more), and the transmission / reception operation is performed at each rotation position. For the probe control means to perform the transmission and reception operation of both the probes Measurement data analysis means for calculating a surface tissue acoustic anisotropy constant from the acoustic velocity data of the surface acoustic wave obtained, and calculating a residual stress of the stress measurement target material based on the obtained constant. And

JP 2010-236882 A JP 2008-76387 A

The technologies disclosed in Patent Documents 1 and 2 are based on the acoustoelastic effect that the sound velocity of the ultrasonic wave propagating through the object to be inspected changes according to the residual stress. However, since the stress dependence (acoustic elastic coefficient) of sound speed in metal materials is generally small, the sound speed of ultrasonic waves propagating through the object to be measured can be measured with high accuracy and stability in order to improve the accuracy of residual stress evaluation. There is a problem that must be done.
Specifically, in order to measure the speed of sound, it is necessary to have an ultrasonic propagation distance as well as an ultrasonic transmission time and reception time (propagation time). It is difficult to keep the propagation distance of the sound wave constant, and the uncertain propagation distance causes an error. Therefore, Patent Documents 1 and 2 both measure longitudinal acoustic waves and transverse acoustic waves to measure the ultrasonic velocity of these ultrasonic waves, and based on the measured acoustic velocity values, residual stress in the material that is the object to be inspected. Try to evaluate. Patent Documents 1 and 2 attempt to increase the measurement accuracy of sound velocity (residual stress) by using both longitudinal and transverse waves to reduce the error factor caused by the uncertainty of the ultrasonic propagation distance. .

  Such Patent Documents 1 and 2 are based on the premise that different ultrasonic probes are used in each of the longitudinal wave sound velocity measurement and the transverse wave sound velocity measurement. Thus, when different ultrasonic probes are used for longitudinal wave sound velocity measurement and shear wave sound velocity measurement, the sound velocity of the longitudinal wave and the transverse wave cannot be measured simultaneously at the same position. Furthermore, the propagation time of the ultrasonic wave when measuring the speed of sound depends not only on the propagation distance of the ultrasonic wave in the inspection object but also on the contact state between the ultrasonic probe and the inspection object. Therefore, in the measurement of ultrasonic waves at different positions using different ultrasonic probes as shown in Patent Documents 1 and 2, the contact state between the probe and the object to be inspected changes at each measurement. Therefore, there is a problem that a measurement error due to this change occurs.

In addition, the techniques disclosed in Patent Documents 1 and 2 evaluate the residual stress in the depth direction in the material, but do not evaluate the residual stress existing in the surface layer of the material. Therefore, Patent Documents 1 and 2 do not disclose the technical contents for evaluating the residual stress existing in the surface layer of the material.
Therefore, in view of the above problems, the present invention suppresses measurement accuracy deterioration due to the contact state of the ultrasonic probe with the object to be inspected with a relatively simple structure, and reduces the residual stress on the surface layer of the object to be inspected. It is an object of the present invention to provide a residual stress evaluation method and a residual stress evaluation apparatus that can measure with high accuracy.

In order to achieve the above-described object, the present invention takes the following technical means.
The residual stress evaluation method of the present invention is a residual stress evaluation method for evaluating the residual stress existing in the surface layer of the specimen sample based on the propagation time of the ultrasonic wave propagating through the surface layer of the specimen specimen, Transmitting a plurality of types of ultrasonic waves having different vibrations to the surface layer of the sample to be inspected, exciting a plurality of types of propagation ultrasonic waves having different vibration forms on the surface layer of the sample to be inspected, and a surface layer of the sample to be inspected. A receiving step for receiving the plurality of types of propagating ultrasonic waves to be propagated, a propagation time of each of the plurality of types of propagating ultrasonic waves received in the receiving step is calculated, and the residual stress is calculated based on the calculated propagation time And an evaluation step for evaluating.

Here, the sending step sends the plural types of ultrasonic waves to a first position on the surface of the subject sample, and the receiving step sends the plural types of propagated ultrasonic waves to the subject sample. The second position may be received from a second position different from the first position on the surface.
The plurality of types of propagating ultrasonic waves received in the receiving step may be Rayleigh waves and surface SH waves.

Further, the sending step sends SH waves and SV waves as the plurality of types of ultrasonic waves, and the receiving step sends SH waves and SV waves sent as the plurality of types of propagation ultrasonic waves in the sending step. It is preferable to receive the Rayleigh wave and the surface SH wave that have been excited and propagated by.
Moreover, the said receiving step is good to receive the said Rayleigh wave and surface SH wave in a respectively different position according to the outgoing angle from the said 2nd position of the propagated Rayleigh wave and surface SH wave.

In addition, the receiving step may detect the Rayleigh wave as a longitudinal wave and detect the surface SH wave as a transverse wave.
The plurality of types of propagating ultrasonic waves received in the receiving step may be Rayleigh waves and surface SV waves.
Further, in the transmitting step, the longitudinal wave or the SV wave is transmitted from the single vibrator of the longitudinal wave or the transverse wave, thereby exciting the Rayleigh wave and the surface SV wave as the plural kinds of propagating ultrasonic waves to the sample to be inspected. It is preferable that the receiving step receives the Rayleigh wave and the surface SV wave propagated by excitation with a single longitudinal wave or transverse wave transducer.

  The residual stress evaluation apparatus according to the present invention is a residual stress evaluation apparatus that evaluates the residual stress existing in the surface layer of the specimen sample based on the propagation time of the ultrasonic wave propagating through the surface layer of the specimen specimen. A plurality of different types of ultrasonic waves are transmitted to the surface layer of the sample to be inspected, thereby transmitting a plurality of types of propagation ultrasonic waves having different vibration forms to the surface layer of the sample to be inspected, and a surface layer of the sample to be inspected. A receiving unit that receives the plurality of types of propagating ultrasonic waves that propagates, and calculates a propagation time of each of the plurality of types of propagating ultrasonic waves received by the receiving unit, and based on the calculated propagation time, the residual stress And an evaluation unit for evaluating.

Here, the transmission unit transmits the plurality of types of ultrasonic waves to a first position on the surface of the subject sample, and the reception unit transmits the plurality of types of propagation ultrasonic waves to the first sample. It is good to receive from the 2nd position on the surface of the said specimen sample different from a position.
Further, the transmission unit includes a single first ultrasonic transducer that transmits the plurality of types of ultrasonic waves, and the reception unit receives a single first ultrasonic wave that receives the plurality of types of propagation ultrasonic waves. It is preferable to have a sonic transducer.

Further, the plurality of types of propagation ultrasonic waves received by the receiving unit may be Rayleigh waves and surface SH waves.
In addition, the sending unit sends SH waves and SV waves as the plurality of types of ultrasonic waves, and the receiving unit sends SH waves and SVs sent by the sending unit as the plurality of types of propagation ultrasonic waves. It is preferable to receive the Rayleigh wave and the surface SH wave that have been excited and propagated by the wave.

  Here, the transmission unit has a single first ultrasonic transducer that transmits the plurality of types of ultrasonic waves, and the reception unit emits the propagated Rayleigh wave from the second position. A second ultrasonic transducer that is provided at a position corresponding to the second ultrasonic transducer and receives the Rayleigh wave, and an ultrasonic transducer different from the second ultrasonic transducer, wherein the second surface of the propagated surface SH wave And a third ultrasonic transducer that is provided at a position corresponding to the emission angle from the position and receives the SH wave.

  In addition, the transmission unit is a fourth ultrasonic transducer that transmits SV waves to the first position, and an ultrasonic transducer that transmits ultrasonic waves at an angle different from the fourth ultrasonic transducer. A fifth ultrasonic transducer that transmits the SH wave to the first position, and the receiving unit is in a position corresponding to an emission angle of the propagated Rayleigh wave from the second position. A second ultrasonic transducer provided to receive the Rayleigh wave, and an ultrasonic transducer different from the second ultrasonic transducer, wherein the propagated surface SH wave is emitted from the second position. It is preferable to include a third ultrasonic transducer that is provided at a position corresponding to a corner and receives the SH wave.

Furthermore, the second ultrasonic transducer may receive the Rayleigh wave as a longitudinal wave, and the third ultrasonic transducer may receive the SH wave as a transverse wave.
In addition, it is preferable that the sending unit is configured with an electromagnetic ultrasonic sensor and the receiving unit is configured with an electromagnetic ultrasonic sensor.
The plurality of types of propagation ultrasonic waves received by the receiving unit may be Rayleigh waves and surface SV waves.

  Further, it is preferable that the transmission unit is configured by a single vibrator of longitudinal wave or shear wave, and the reception unit is configured by a single oscillator of longitudinal wave or transverse wave.

  According to the residual stress evaluation method and the residual stress evaluation apparatus of the present invention, the measurement of the residual stress of the object to be inspected can be performed with a relatively simple configuration and high accuracy.

It is a figure which shows schematic structure of the residual stress evaluation apparatus by 1st Embodiment of this invention. It is a figure which expands and shows schematic structure of the transmission probe of the residual stress evaluation apparatus by this embodiment, and a receiving probe. It is a figure which expands and shows schematic structure of the transmission probe and reception probe of the residual stress evaluation apparatus by 2nd Embodiment of this invention. In the residual stress evaluation apparatus by this embodiment, it is a figure which expands and shows schematic structure when a receiving probe is employ | adopted as a transmitting probe. It is a figure which shows schematic structure of the electromagnetic ultrasonic sensor used for the transmission probe and the receiving probe of the residual stress evaluation apparatus by 3rd Embodiment of this invention. It is a figure which shows schematic structure of the residual stress evaluation apparatus by this embodiment. It is a figure which shows schematic structure of the modification of the electromagnetic ultrasonic sensor used for the transmission probe and reception probe by this embodiment. It is a figure which shows schematic structure of the residual stress evaluation apparatus by 4th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol and the same name shall be attached | subjected to the same structural member common to each embodiment demonstrated below. Therefore, the same description will not be repeated for the components having the same reference numerals and the same names.
[First Embodiment]
Hereinafter, the residual stress evaluation apparatus 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2 and a residual stress evaluation method using the residual stress evaluation apparatus 1 will be described.

FIG. 1 is a diagram showing a schematic configuration of a residual stress evaluation apparatus 1 according to the present embodiment. FIG. 2 is an enlarged view showing a schematic configuration of the transmission probe 2 and the reception probe 3 of the residual stress evaluation apparatus 1.
The residual stress evaluation apparatus 1 converts, for example, residual stress existing in the surface layer of an inspection object (inspection sample) such as a machine part or a structure made of steel into ultrasonic waves that propagate through the surface layer of the inspection sample. It is an apparatus for evaluating (measuring) based on the above. Specifically, the residual stress evaluation apparatus 1 propagates ultrasonic waves to the surface layer of the sample to be inspected, measures the propagation time of the propagated ultrasonic waves, and uses the propagation time of the ultrasonic waves to use the surface layer of the sample to be inspected. To evaluate (measure) the residual stress present in In the present embodiment, a rectangular parallelepiped-shaped measurement sample W made of a steel material is exemplified as the sample to be inspected.

  Here, the surface layer is a region in a predetermined depth range below the surface of the measurement sample W (subcutaneous surface), for example, a region in a range shallower than a depth of several mm. In particular, since the residual stress in the depth region about the ultrasonic wavelength from the surface of the measurement sample W can be evaluated, the surface layer may be defined as a depth region about the ultrasonic wave wavelength to be used. At that time, since the wavelength of the ultrasonic wave is variable (0.1 mm to several mm) depending on the change of the frequency, the surface layer can be defined as a region in a range shallower than the depth of several mm.

  As shown in FIG. 1, the residual stress evaluation apparatus 1 is the same as the transmission probe 2 that is arranged on the surface of a measurement sample W that is a sample to be inspected and transmits (transmits) ultrasonic waves to the measurement sample W. A receiving probe 3 is disposed on the surface of the sample W at a position different from that of the transmission probe 2 and receives an ultrasonic wave transmitted from the transmission probe 2 and propagated through the surface layer of the measurement sample W. Furthermore, the residual stress evaluation apparatus 1 includes a pulse generator 4 for generating an ultrasonic wave in the transmission probe 2 and an amplifier 5 that collects a reception signal that is an ultrasonic signal received by the reception probe 3. 6 and a waveform sampling device 7 and an evaluation device (evaluation unit) 8 for evaluating the residual stress in the propagation path of the ultrasonic wave corresponding to the received signal based on the collected received signal.

First, with reference to FIG. 2, the transmitting probe 2 and the receiving probe 3 which are characteristic structures of the residual stress evaluation apparatus 1 will be described in detail, and a pulse generator 4, amplifiers 5 and 6, and a waveform sampling apparatus. 7 and the evaluation device 8 will be described later.
The transmission probe (transmission unit) 2 is an ultrasonic probe in which, for example, a plate-like piezoelectric element 20 is mounted on an ultrasonic propagation medium 21. When a pulse voltage of a predetermined voltage is applied to the piezoelectric element 20, an ultrasonic wave having a predetermined frequency is output from the flat plate surface of the piezoelectric element 20, and the output ultrasonic wave is applied to the ultrasonic propagation medium 21 of the transmission probe 2. It is sent to the outside through a sending surface (ultrasonic sending surface) 22 which is the formed opening surface.

  The piezoelectric element 20 vibrates by a pulse having a predetermined voltage applied thereto, and thereby outputs ultrasonic waves having a predetermined frequency from the flat plate surface (output surface) of the piezoelectric element 20. The piezoelectric element 20 is arranged at an oblique angle so that the output direction of the ultrasonic waves is not parallel or perpendicular to the ultrasonic transmission surface 22 of the transmission probe 2 and is output from the piezoelectric element 20. The ultrasonic waves are transmitted from the ultrasonic transmission surface 22 to the outside along an oblique direction different from the direction perpendicular to the ultrasonic transmission surface 22. That is, when the transmission probe 2 is disposed on the surface of the measurement sample W by bringing the ultrasonic transmission surface 22 into contact with the surface of the measurement sample W, the ultrasonic wave transmitted from the ultrasonic transmission surface 22 is measured. Incident from an oblique direction that is neither parallel nor perpendicular to the surface of the sample W.

  Further, the piezoelectric element 20 outputs transverse ultrasonic waves. The vibration component included in the ultrasonic wave output from the piezoelectric element 20 is at least a component (vibration component) incident on the ultrasonic wave sending surface 22 while vibrating in parallel with the output surface of the piezoelectric element 20 and the ultrasonic wave sending surface 22. A) and a component (vibration component B) that is incident on the ultrasonic transmission surface 22 while vibrating in a direction perpendicular to the vibration direction of the vibration component A.

The description will be supplemented with reference to FIGS. 1 and 2 are views of the transmission probe 2 seen from the side so that the output surface of the piezoelectric element 20 is perpendicular to the paper surface, and the vibration component A is the paper surface of FIGS. 1 and 2. The vibration component B is a component parallel to the paper surface of FIGS. 1 and 2 and the output surface of the piezoelectric element 20.
The piezoelectric element 20 outputs an ultrasonic wave including such vibration component A and vibration component B, and the output ultrasonic wave is oblique at an angle corresponding to the angle of the output surface of the piezoelectric element 20 with respect to the ultrasonic transmission surface 22. Then, it passes through the ultrasonic transmission surface 22 and is transmitted to the outside of the transmission probe 2.

  As described above, the piezoelectric element 20 outputs ultrasonic waves in a vibration form such as the vibration component A and the vibration component B. The piezoelectric element 20 is shown in the piezoelectric element 20 of the transmission probe 2 in FIGS. By oscillating along the direction component of one vector, an SH wave which is a horizontal component of a transverse wave is output as a vibration component A that vibrates in parallel with the output surface of the piezoelectric element 20 and the ultrasonic wave transmission surface 22, and the vibration component An SV wave that is a vertical component of a transverse wave is output as a vibration component B that vibrates in a direction perpendicular to the vibration direction of A. As described above, the piezoelectric element 20 of the transmission probe 2 transmits SH waves and SV waves as a plurality of types of ultrasonic waves.

  As described above, the piezoelectric element 20 of the transmission probe 2 is a single first ultrasonic transducer that transmits SH waves and SV waves as ultrasonic waves. With the configuration in which the piezoelectric element 20 is a single first ultrasonic transducer that is not separated, a plurality of types of propagation paths of ultrasonic waves sent from the piezoelectric element 20 to the measurement sample W can be shared, It is possible to prevent the problem that the propagation distance fluctuates due to a different path for each type of ultrasonic wave.

  As shown in FIGS. 1 and 2, the transmission probe 2 having the piezoelectric element 20 described above is disposed on the surface of the measurement sample W by bringing the ultrasonic transmission surface 22 into contact with the surface of the measurement sample W. A contact medium supply unit (not shown) that supplies a contact medium that fills between the piezoelectric element 20 and the ultrasonic wave sending surface 22 or between the ultrasonic wave sending surface 22 and the surface of the measurement sample W. The contact medium is a substance that transmits ultrasonic waves, such as water, glycerin paste, and oil, and is a medium that transmits ultrasonic waves output from the piezoelectric element 20 to the surface of the measurement sample W.

The operation of the transmission probe 2 will be described with reference to FIG. When the transmission probe 2 is placed on the surface of the measurement sample W with the ultrasonic transmission surface 22 in contact with the surface of the measurement sample W, the piezoelectric element 20 of the transmission probe 2 is placed on the ultrasonic transmission surface 22. It is arranged so as to be inclined with respect to the surface of the measurement sample W by the same angle with respect to.
When a pulse voltage is applied to the piezoelectric element 20 from a pulse generator 4 to be described later, the piezoelectric element 20 causes an SH wave (vibration component A) and an SV wave (vibration component) having a frequency corresponding to the applied pulse voltage. The ultrasonic wave including B) is output.

The SH wave and the SV wave that are ultrasonic waves output from the output surface of the piezoelectric element 20 pass through the ultrasonic wave transmission surface 22 of the transmission probe 2 to the same position (first position) on the surface of the measurement sample W. , And sent in an oblique direction with respect to the surface of the measurement sample W.
The SH wave and the SV wave sent obliquely to the surface of the measurement sample W are incident obliquely on the same position (first position) on the surface of the measurement sample W, and are vibrated on the surface layer of the measurement sample W. Exciting multiple types of different ultrasonic waves. Since the ultrasonic wave excited by the ultrasonic wave incident obliquely on the surface of the measurement sample W propagates as a surface wave (surface acoustic wave) on the surface layer of the measurement sample W, it will be referred to as a propagation ultrasonic wave in the following description.

As shown in FIG. 2, the SH wave incident on the surface of the measurement sample W in an oblique direction excites a surface SH wave indicated by a broken line in the figure as a propagating ultrasonic wave propagating through the surface layer of the measurement sample W. Further, the SV wave incident on the surface of the measurement sample W in an oblique direction excites a Rayleigh wave indicated by a solid line in the figure as a propagation ultrasonic wave propagating through the surface layer of the measurement sample W.
In propagating ultrasonic waves with different vibration forms, Rayleigh waves are characterized by high excitation efficiency and propagating with low attenuation on the surface layer of the measurement sample W, while surface SH waves are characterized by high sensitivity to stress. is there. For this reason, in this embodiment, Rayleigh waves and surface SH waves are exemplified as propagation ultrasonic waves having different vibration forms. In addition to the Rayleigh wave and the surface SH wave, various vibration forms of ultrasonic waves can be used depending on the purpose.

In addition, the definition of the ultrasonic vibration form such as the transverse wave, the longitudinal wave, the SH wave, the SV wave, the surface SH wave, and the Rayleigh wave used in the description so far is defined by a person skilled in the art in the technical field dealing with vibration including ultrasonic waves. Same definition as recognized.
To summarize the above, the transmission probe 2 is arranged on the surface of the measurement sample W that is the sample to be inspected, and the plurality of types having different vibration forms from the piezoelectric element 20 in an oblique direction that is neither horizontal nor vertical to the surface. Are transmitted to the surface layer of the measurement sample W, so that a plurality of types of propagation ultrasonic waves (surface SH waves and Rayleigh waves) having different vibration forms are excited on the surface layer of the measurement sample W.

In this manner, the transmission probe 2 causes the Ray wave and the surface SH wave to be incident obliquely on the surface of the measurement sample W with the ultrasonic wave including the SH wave and the SV wave that are single shear waves having polarization. The transmission probe 2 can be realized with a simple and inexpensive configuration.
Surface SH waves and Rayleigh waves, which are propagating ultrasonic waves excited at the same position (first position) on the surface of the measurement sample W by the SH waves and SV waves sent from the transmission probe 2, are almost in the same direction. Propagates the surface layer of the measurement sample W toward the surface.

  With reference to FIG. 2, the reception probe (reception unit) 3 is an ultrasonic probe in which, for example, a plate-like piezoelectric element 30 is mounted on an ultrasonic propagation medium 31. The piezoelectric element 30 receives a propagating ultrasonic wave incident on the inside of the ultrasonic wave propagation medium 31 from an incident surface (ultrasonic wave incident surface) 32 which is an opening surface formed in the reception probe 3 31, thereby receiving a predetermined ultrasonic wave. Generate voltage. The flat piezoelectric element 30 is a member having substantially the same configuration as the piezoelectric element 20 of the transmission probe 2, and the flat plate surface that receives the propagation ultrasonic waves is used as the ultrasonic incident surface 32 of the reception probe 3. In contrast, they are not parallel or vertical, but are inclined at an oblique angle.

  The piezoelectric element 30 detects a propagating ultrasonic wave by receiving a plurality of types of propagating ultrasonic waves propagating through the surface layer of the measurement sample W and generating a predetermined voltage. For example, the piezoelectric element 30 receives a surface SH wave. The piezoelectric element 30a for detecting the transverse wave and the piezoelectric element 30b for receiving the Rayleigh wave are stacked and configured as a single piezoelectric element 30 that is not separated. The piezoelectric element 30 having such a configuration includes a single unit having a transverse wave (vibration component A in transmission) detection unit that detects surface SH waves and a transverse wave (vibration component B in transmission) detection unit that detects SV waves caused by Rayleigh waves. It can also be said that it is a piezoelectric element.

  The receiving probe 3 having the piezoelectric element 30 is a plurality of types of propagating ultrasonic waves having different vibration forms from the Rayleigh wave and the surface SH wave which are excited and propagated by the SH wave and SV wave transmitted from the transmitting probe 2. And the voltage generated by the reception is output to the outside as detection signals of Rayleigh waves and surface SH waves. Specifically, surface SH waves and Rayleigh waves, which are propagation ultrasonic waves that have propagated through the surface layer of the measurement sample W, propagate into the reception probe 3 from the ultrasonic incident surface 32 of the reception probe 3 and The light enters the flat plate surface of the piezoelectric element 30 facing the sound wave incident surface 32. The incident surface SH wave is detected by the transverse wave detecting piezoelectric element 30a, and the Rayleigh wave is similarly detected as the SV wave by the transverse wave detecting piezoelectric element 30b.

As described above, the piezoelectric element 30 of the reception probe 3 is a single first ultrasonic transducer that receives Rayleigh waves and surface SH waves as a plurality of types of propagating ultrasonic waves.
That is, when the ultrasonic incident surface 32 of the reception probe 3 is brought into contact with a second position different from the first position described above on the propagation path of the surface SH wave and the Rayleigh wave that are propagation ultrasonic waves, The propagating ultrasonic wave propagated through the surface layer of the measurement sample W is incident on the ultrasonic incident surface 32 in an oblique direction that is neither parallel nor perpendicular to the surface of the measurement sample W at the second position. Thereby, the reception probe 3 receives a plurality of types of propagating ultrasonic waves such as surface SH waves and Rayleigh waves from the second position on the surface of the measurement sample W.

At this time, as shown in FIG. 2, when the receiving probe 3 is arranged at the second position so that the flat surface of the piezoelectric element 30 facing the ultrasonic incident surface 32 faces the upstream side in the propagation direction of the propagation ultrasonic waves. The piezoelectric element 30 of the reception probe 3 can efficiently receive the propagation ultrasonic wave propagated in the reception probe 3.
The reception probe 3 having the above-described piezoelectric element 30 is arranged on the surface of the measurement sample W by bringing the ultrasonic incident surface 32 into contact with the surface of the measurement sample W, similarly to the transmission probe 2. Then, a contact medium supply unit (not shown) that supplies a contact medium that fills between the piezoelectric element 30 and the ultrasonic incident surface 32 and between the ultrasonic incident surface 32 and the surface of the measurement sample W is provided.

An arrangement of the transmission probe 2 and the reception probe 3 on the surface of the measurement sample W will be described with reference to FIG.
The ultrasonic transmission surface of the transmission probe 2 on the first position so that the region for measuring the residual stress is sandwiched between the first position for exciting the propagation ultrasonic wave and the second position for receiving the propagation ultrasonic wave. The transmitting probe 2 and the receiving probe 3 are arranged by contacting the ultrasonic incident surface 32 of the receiving probe 3 on the second position. At this time, the transmission probe 2 is arranged so that the propagation direction of the propagation ultrasonic wave faces the region where the residual stress is measured, and the reception probe 3 has the flat surface of the piezoelectric element 30 in the propagation direction of the propagation ultrasonic wave. Arranged to face upstream.

With such an arrangement, the first position and the second position are separated by a distance L corresponding to the size of the region where the residual stress is measured, and both the surface SH wave and the Rayleigh wave, which are propagating ultrasonic waves, are both It propagates through the surface layer of the measurement sample W by the distance L.
That is, by using the transmission probe 2 and the reception probe 3 arranged as described above, a plurality of ultrasonic waves having different vibration forms can be propagated by the same distance L. Not only the distance L between the first position and the second position, but also the ultrasonic wave from the piezoelectric element of the transmission probe 2 to the piezoelectric element of the reception probe 3 through the first position and the second position. The propagation distance is the same regardless of the ultrasonic vibration mode.

Next, another configuration for evaluating the residual stress on the surface layer of the measurement sample W by driving the transmission probe 2 and the reception probe 3 described above will be described with reference to FIG.
The pulse generator 4 is connected to the transmission probe 2 and generates an ultrasonic wave on the piezoelectric element 20 by applying a voltage signal (pulse signal) of a predetermined voltage to the piezoelectric element 20 of the transmission probe 2. At the same time, a trigger signal for notifying the generation timing of the ultrasonic wave is output to the waveform sampling device 7 described later simultaneously with the voltage signal.

  The amplifiers 5 and 6 are amplifiers connected to the reception probe 3, and amplify the intensity of the detection signal output from the piezoelectric element 30 of the reception probe 3 and output the amplified signal to the waveform sampling device 7 described later. . The amplifier 5 amplifies the Rayleigh wave detection signal output from the piezoelectric element 30b and outputs the amplified signal to the waveform sampling device 7. The amplifier 6 amplifies the surface SH wave detection signal output from the piezoelectric element 30a and outputs the waveform sampling device. 7 is output.

  The waveform sampling device 7 receives the trigger signal output from the pulse generator 4 and receives the detection signals of the Rayleigh wave and the SH wave output from the amplifiers 5 and 6 and acquires the waveform of the detection signal. At this time, the reception of the trigger signal can be regarded as the timing at which the piezoelectric element 20 of the transmission probe 2 outputs the ultrasonic wave, and the reception of the detection signal of the Rayleigh wave and the SH wave is the reception probe 3. It can be considered that this is the timing at which the piezoelectric element 30 receives the Rayleigh wave and the SH wave (the Rayleigh wave and the SH wave reach the reception probe 3).

Therefore, waveform acquisition apparatus 7 calculates the propagation time T _R for by measuring the time between the receipt of the trigger signal and receiving a Rayleigh wave detection signal Rayleigh wave, the detection signal of the surface SH waves from the reception of the trigger signal measuring the time until the reception for calculating the propagation time T _S of the surface SH wave. Waveform acquisition apparatus 7 outputs the propagation time of these calculated Rayleigh wave T _R and the surface SH wave propagation time T _S to the evaluation device 8 which will be described later.

The evaluation device 8 acquires the propagation time T _R of the Rayleigh wave and the propagation time T _S of the surface SH wave output from the waveform sampling device 7, and propagates based on the acquired propagation time T _R and the propagation time T _S. The residual stress existing in the surface layer of the measurement sample W through which the Rayleigh wave and the surface SH wave that are ultrasonic waves propagated is evaluated.
First, a basic concept for evaluating the residual stress existing on the surface layer of the measurement sample W will be described, and then a method for evaluating the residual stress performed by the evaluation device 8 will be described.

Propagation time T _R of Rayleigh wave, the distance the propagation distance Rayleigh wave L, the acoustic velocity V _R of Rayleigh wave in the measurement specimen W in which the residual stress is not _present, the sound modulus C _R for Rayleigh wave in the measurement specimen _W, Rayleigh waves It can be expressed using the stress (residual stress) σ existing in the propagation path. Under formula (1) is the propagation time T _R of Rayleigh wave, which is an example of a relational expression expressed by using propagation distance L, the acoustic velocity V _R, the sound modulus C _R, and the residual stress sigma.

In the formula (1), the propagation time T _R of Rayleigh wave can be obtained from the waveform acquisition apparatus 7, the propagation distance L Rayleigh wave probe received from a first position in which transmitting probe 2 is arranged It can be acquired as a distance to the second position where the touch 3 is arranged.

Here, the propagation path of the Rayleigh wave in the case of calculating the propagation time T _R by waveform acquisition apparatus 7 described above, received from the piezoelectric element 20 of the transmission probe 2 via the first and second positions Up to the piezoelectric element 30 of the probe 3, it does not completely coincide with the distance L from the first position to the second position. That is, the propagation distance of the Rayleigh wave is about the distance from the piezoelectric element 20 of the transmission probe 2 to the surface of the measurement sample W and the surface of the measurement sample W to the piezoelectric element 30 of the reception probe 3 before and after the distance L. In other words, the propagation distance in the transmission probe 2 and the propagation distance in the reception probe 3 are added. Therefore, existing before and after the distance L, by correcting the propagation time T _R in consideration of the propagation distance of the transmission probe in probe 2 and the receiving probe 3, to calculate a more accurate propagation time T _R it Can do.

Acoustic velocity V _R of Rayleigh wave in the measurement specimen W in which the residual stress is not present, a value which can be measured in advance to prepare a measurement sample W residual stress is not present. Sound modulus C _R for Rayleigh wave in the measurement sample W are the physical properties of the measurement sample W, is a value that can be acquired in advance.
Thus, the propagation time T _R, the propagation distance L, it is possible to obtain the acoustic velocity V _R, and the sound modulus C _R, the like is used equation (1), the residual stress existing in the propagation path of Rayleigh waves σ can be obtained (evaluated).

Similarly to the propagation time T _R of the Rayleigh wave, the propagation time T _S of the surface SH wave is the distance L which is the propagation distance of the surface SH wave, the sound velocity V _S of the surface SH wave in the measurement sample W where no residual stress exists, and the measurement. Using the acoustoelastic coefficient C _S for the surface SH wave in the sample W and the stress (residual stress) σ existing in the propagation path of the surface SH wave, it can be expressed as a relational expression exemplified in the following equation (2). it can.

Also in this equation (2), the propagation time T _S , the propagation distance L, the sound velocity V _S , and the acoustoelastic coefficient C _S can be acquired, so the residual stress σ existing in the propagation path of the surface SH wave is obtained ( Can be evaluated).

  If the above formula (1) or formula (2) is used, it is possible to evaluate the residual stress existing in the surface layer of the measurement sample W using either the Rayleigh wave or the surface SH wave. However, since it is difficult to accurately obtain the distance L from the first position to the second position when the transmission probe 2 and the reception probe 3 are arranged, the distance L is always a measurement error. May be included. This distance L is also affected by the contact state of the transmission probe 2 and the reception probe 3 with the measurement sample W, such as the tilt and lift amount with respect to the surface of the measurement sample W, but this unstable contact state is always maintained. Since it is difficult to keep constant, it is very difficult to eliminate the error of the distance L.

Therefore, it is very difficult to accurately evaluate the residual stress using only one of the Rayleigh wave and the surface SH wave, that is, only one vibration form of ultrasonic wave, and the residual stress may include an error in the evaluation. It is desirable to eliminate the distance L that is difficult to obtain accurately.
In the residual stress evaluation apparatus 1 including the transmission probe 2 and the reception probe 3 described above, propagation paths of Rayleigh waves and surface SH waves, which are a plurality of types of ultrasonic waves having different vibration forms, are common (same). The distance L from the first position to the second position has the same value.

  Therefore, the evaluation device 8 uses a relational expression that excludes the distance L by using the relational expressions exemplified in the expressions (1) and (2) as exemplified in the following expression (3).

The relational expression exemplified in the equation (3) includes the residual stress σ, the Rayleigh wave propagation time T _R , the Rayleigh wave velocity V _R , the Rayleigh wave acoustoelastic coefficient C _R , the surface SH wave propagation time T _S , the surface It is an example of the relational expression expressed based on the acoustic velocity V _{S of} the SH wave and the acoustoelastic coefficient C _S of the surface SH wave. If the relational expression as exemplified in Expression (3) is used, the distance L that easily includes the error and the influence of the contact state of the ultrasonic probe can be excluded. It is possible to suppress deterioration in measurement accuracy due to the contact state of the probe 2 and the reception probe 3 with the measurement sample W. Therefore, according to the residual stress evaluation apparatus 1 of the present embodiment, the residual stress existing on the surface layer of the measurement sample W is evaluated (measured) with high accuracy and stability using both the Rayleigh wave and the surface SH wave. be able to.

The operation of the residual stress evaluation apparatus 1 having the above configuration will be described.
The transmission probe 2 and the reception probe 3 are brought into contact with the ultrasonic transmission surface 22 of the transmission probe 2 on the first position so that the region where the residual stress is measured is sandwiched, and the second The ultrasonic incident surface 32 of the receiving probe 3 is brought into contact with the position of the measurement probe W and placed on the surface of the measurement sample W.
After this arrangement, the pulse generator 4 applies a pulse voltage to the piezoelectric element 20 of the transmission probe 2 and simultaneously outputs a trigger signal to the waveform sampling device 7.

The piezoelectric element 20 of the transmission probe 2 to which the pulse current is applied outputs SH waves and SV waves as a plurality of types of ultrasonic waves having different vibration forms, and sends them to a first position on the surface of the measurement sample W.
The transmitted SH wave and SV wave are incident on the first position on the surface of the measurement sample W, and on the surface layer of the measurement sample W, Rayleigh waves and surface SH waves, which are a plurality of types of propagating ultrasonic waves having different vibration forms. Excited. This is the sending step and continues to the receiving step.

The excited Rayleigh wave and the surface SH wave propagate through the surface layer of the measurement sample W, and the piezoelectric element 30 of the reception probe 3 receives the Rayleigh wave and the surface SH wave from the second position on the surface of the measurement sample W. .
The piezoelectric element 30 of the reception probe 3 outputs the received Rayleigh wave and surface SH wave detection signals to the amplifiers 5 and 6. This is the reception step and continues to the evaluation step.
The amplifiers 5 and 6 amplify the received Rayleigh wave and surface SH wave detection signals and output the amplified signals to the waveform sampling device 7.

The waveform sampling device 7 receives the Rayleigh wave received by the piezoelectric element 30 of the receiving probe 3 from the trigger signal received from the pulse generator 4 and the Rayleigh wave and surface SH wave detection signals received from the amplifiers 5 and 6. and the propagation time is the propagation time of the surface SH wave T _R and the propagation time to calculate a T _S, and outputs it to the evaluation device 8.
The evaluation apparatus 8 uses the relational expression exemplified in the above-described formula (3), and does not depend on the propagation distance L of the propagation ultrasonic wave, and the residual stress existing on the surface layer of the measurement sample W propagated by the propagation ultrasonic wave. Obtain (evaluate) σ. This is the evaluation step.

According to the residual stress evaluation apparatus 1 having the above configuration, the residual stress can be evaluated in a depth region about the wavelength of the propagating ultrasonic wave. Therefore, by changing the frequency of the propagating ultrasonic wave stepwise, 0 can be obtained. The depth distribution of residual stress can be evaluated in the range of .1 to several mm.
Moreover, since the residual stress evaluation apparatus 1 excites the Rayleigh wave and the surface SH wave by simultaneously applying a compressive force and a shearing force to a part of the surface of the measurement sample W by the SV wave and the SH wave, the transmission probe. 2 and the influence on the propagation time T _R and the propagation time T _S due to the change in the position and contact state of the reception probe 3 can be suppressed.
[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIGS. 3 and 4.

FIG. 3 is an enlarged view showing a schematic configuration of the transmission probe 2 and the reception probe 9 of the residual stress evaluation apparatus 10 according to the present embodiment. FIG. 4 is an enlarged view showing a schematic configuration when the reception probe 9 is adopted as a transmission probe in the residual stress evaluation apparatus 10.
The residual stress evaluation apparatus 10 according to the present embodiment has substantially the same configuration as that of the residual stress evaluation apparatus 1 according to the first embodiment, and a reception probe 9 is used instead of the reception probe 3 of the residual stress evaluation apparatus 1. It is provided as a receiver. In the residual stress evaluation apparatus 10, the configuration other than the reception probe 9 is the same as that of the residual stress evaluation apparatus 1 according to the first embodiment.

Hereinafter, the configuration of the reception probe 9 will be described with reference to FIG. 3. Before that, the premise of the configuration of the reception probe 9 will be described.
In the first embodiment described above, the surface SH wave and Rayleigh wave propagated through the surface layer of the measurement material W are contacted between the surface of the measurement sample W and the ultrasonic incident surface 32 from the second position on the surface of the measurement sample W. The light is refracted on the surface and propagates into the receiving probe 3 as an SH wave and a Rayleigh wave. However, at this time, the SH wave and the Rayleigh wave have different refraction angles, and propagate from the ultrasonic incident surface 32 to the ultrasonic transducer 30 through different paths.

  Specifically, the propagation direction of the SH wave, that is, the exit angle of the SH wave from the second position is determined by this method when the normal to the contact surface between the surface of the measurement sample W and the ultrasonic incident surface 32 is used as a reference. It is inclined about 20 degrees in the propagation direction of the surface SH wave with respect to the line. Specifically, the SH wave is emitted from the second position into the reception probe 3 as a transverse SH wave with an emission angle of about 20 degrees. The Rayleigh wave emission angle, that is, the emission angle of the Rayleigh wave from the second position is inclined about 50 degrees in the Rayleigh wave propagation direction with respect to this normal line. Specifically, the Rayleigh wave is emitted as a longitudinal wave with an emission angle of about 50 degrees in addition to being emitted as a transverse SV wave.

Such a difference in the emission angle of the SH wave and Rayleigh wave is caused by the fact that the measurement sample W through which the SH wave and Rayleigh wave propagate is made of steel, and a metal that can obtain a sound speed comparable to the sound speed in steel. If the measurement material W is constituted by, for example, the emission angles of the SH wave and the Rayleigh wave are substantially the above-described angles.
Therefore, with reference to FIG. 3, the reception probe 9 which is a reception unit has substantially the same configuration as the reception probe 3 described in the first embodiment, and corresponds to the ultrasonic propagation medium 31. The ultrasonic wave propagation medium 91 and the ultrasonic wave incident surface 92 corresponding to the ultrasonic wave incident surface 32 are provided, and the piezoelectric element unit 90 is provided instead of the piezoelectric element 30.

  The piezoelectric element section 90 includes a piezoelectric element 90a (second ultrasonic transducer) corresponding to the piezoelectric element 30a constituting the piezoelectric element 30, and a piezoelectric element 90b (third ultrasonic transducer) corresponding to the piezoelectric element 30b. The piezoelectric element 90a and the piezoelectric element 90b are independent members that are not stacked on each other. The piezoelectric element 90a is for detecting a transverse wave that receives an SH wave in the same manner as the piezoelectric element 30a, and the piezoelectric element 90b receives a Rayleigh wave in the same manner as the piezoelectric element 30b.

In the receiving probe 9 including such a piezoelectric element portion 90, the piezoelectric element 90a is disposed so as to receive the SH wave emitted from the second position substantially vertically, and the piezoelectric element 90b is disposed at the second position. It arrange | positions so that the Rayleigh wave radiate | emitted from may be received.
As a result, the piezoelectric element 90a is formed with the receiving surface on the ultrasonic propagation medium 91 in order to receive the SH wave whose output angle from the second position is inclined by about 20 degrees with respect to the normal line. The incident surface (ultrasonic incident surface) 92 that is an opening surface is inclined at about 20 degrees. In addition, the piezoelectric element 90b receives a Rayleigh wave whose output angle from the second position is inclined by about 50 degrees with respect to the normal line, so that the reception surface is about 50 degrees with respect to the incident surface 92. It is placed at an angle.

Furthermore, the piezoelectric element 90a is connected to the amplifier 6 described in the first embodiment, and the piezoelectric element 90b is connected to the amplifier 5 described in the first embodiment.
The configuration of the reception probe 9 is summarized as follows.
The receiving probe 9 is provided at a position corresponding to the emission angle from the second position of the Rayleigh wave propagated through the surface layer of the measurement sample W, and receives the Rayleigh wave. The piezoelectric element 90b (second ultrasonic transducer) ) And an ultrasonic transducer different from the piezoelectric element 90b, and is provided at a position corresponding to the emission angle from the second position of the surface SH wave propagated through the surface layer of the measurement sample W and receives the SH wave. Piezoelectric element 90a (third ultrasonic transducer).

Then, the piezoelectric element 90b that is the second ultrasonic transducer receives the Rayleigh wave as a longitudinal wave, and the piezoelectric element 90a that is the third ultrasonic transducer receives an SH wave as a transverse wave.
The operation of the residual stress evaluation apparatus 10 provided with the reception probe 9 will be described.
The operation of the residual stress evaluation apparatus 10 is substantially the same as the operation of the residual stress evaluation apparatus 1 according to the first embodiment, and only the reception step is different. Therefore, a reception step will be described for the operation of the residual stress evaluation apparatus 10 according to the present embodiment.

  In the reception step subsequent to the transmission step, the excited Rayleigh wave and the surface SH wave propagate as propagation ultrasonic waves on the surface layer of the measurement sample W, and the piezoelectric element 90 of the reception probe 3 transmits the propagated Rayleigh wave and surface SH wave. The Rayleigh wave and the surface SH wave are received at different positions by the piezoelectric element 90b and the piezoelectric element 90a provided according to the emission angle from the second position. At this time, the piezoelectric element 90b detects the Rayleigh wave as a longitudinal wave, and the piezoelectric element 90a detects the surface SH wave as a transverse wave.

The piezoelectric element 90 a of the reception probe 9 outputs the received surface SH wave detection signal to the amplifier 6, and outputs the received Rayleigh wave detection signal to the amplifier 5. This is the reception step and continues to the evaluation step.
According to the residual stress evaluation apparatus 10 according to the present embodiment, the piezoelectric element 90a and the piezoelectric element 90b that are provided at positions suitable for reception of SH waves and Rayleigh waves whose separation angles of the emission angles are significantly different from about 30 degrees. Can be received. Accordingly, the surface SH wave and the Rayleigh wave propagated through the measurement sample W can be received without causing interference with each other, so that each ultrasonic wave can be received with a high S / N ratio.

At the end of the present embodiment, a modification of the present embodiment will be described with reference to FIG.
As a modification of the present embodiment, the residual stress evaluation apparatus 10 may include a transmission probe 2 a having the same configuration as that of the reception probe 9 instead of the transmission probe 2.
Similar to the reception probe 9, the transmission probe 2a corresponds to the ultrasonic wave propagation medium 21a corresponding to the ultrasonic wave propagation medium 91, the ultrasonic wave incident surface 22a corresponding to the ultrasonic wave incident surface 92, and the piezoelectric element 90a. A piezoelectric element 20b corresponding to the piezoelectric element 20a and the piezoelectric element 90b is provided. When a pulse voltage is applied from the pulse generator 4 to the piezoelectric element 20a and the piezoelectric element 20b of the transmission probe 2a, the piezoelectric element 20a (fifth ultrasonic transducer) responds to the applied pulse voltage. The ultrasonic wave including the SH wave having the frequency (vibration component A) is output to the first position described above, and the piezoelectric element 20b (fourth ultrasonic transducer) has the longitudinal wave having the frequency corresponding to the applied pulse voltage. Sound waves are output to the first position described above. That is, in the transmission probe 2a, the piezoelectric element 20a and the piezoelectric element 20b have two ultrasonic transducers that transmit ultrasonic waves at different angles.

  In this way, by using the two piezoelectric elements 20a and 20b to excite the SH wave and the longitudinal wave, by individually controlling the voltage signal level of the pulse voltage applied to the piezoelectric elements 20a and 20b, The intensity of the SH wave and longitudinal wave sent out by the piezoelectric elements 20a and 20b can be individually controlled. By individually controlling the intensity of the SH wave and the longitudinal wave to be transmitted, it is advantageous for optimizing the S / N ratio of the SH wave and the Rayleigh wave received by the reception probe 9.

Also with the residual stress evaluation apparatus 10 of the present embodiment, the propagation distance L of the propagation ultrasonic wave that is likely to include the error and the influence of the contact state of the ultrasonic probe can be excluded. In addition, it is possible to suppress deterioration in measurement accuracy due to the contact state of the transmission probe 2 and the reception probe 9 with the measurement sample W. Therefore, according to the residual stress evaluation apparatus 10 of the present embodiment, the residual stress existing on the surface layer of the measurement sample W is evaluated (measured) with high accuracy and stability using both the Rayleigh wave and the surface SH wave. be able to.
[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIGS. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals.

  FIG. 5 is a diagram showing a schematic configuration of an electromagnetic ultrasonic sensor 400 (400a, 400b) used in the transmission probe 200 and the reception probe 300 of the residual stress evaluation apparatus 100 according to the present embodiment. FIG. 6 is a diagram illustrating a schematic configuration of the residual stress evaluation apparatus 100 according to the present embodiment. FIG. 7 is a diagram showing a schematic configuration of a modified example of the electromagnetic ultrasonic sensor 400 used in the transmission probe 200 and the reception probe 300 according to the present embodiment.

The electromagnetic ultrasonic sensor 400 is used for the transmission probe 200 and the reception probe 300 of the residual stress evaluation apparatus 100 to transmit or receive ultrasonic waves. The configuration of the electromagnetic ultrasonic sensor 400 will be described. First, the configuration of the residual stress evaluation apparatus 100 including the transmission probe 200 and the reception probe 300 will be described.
With reference to FIG. 6, the residual stress evaluation apparatus 100 according to the present embodiment, for example, on the surface layer of an object to be inspected (sample to be inspected) such as a machine part or a structure made of steel, as in the first embodiment. It is an apparatus that evaluates (measures) the existing residual stress based on ultrasonic waves that propagate through the surface layer of the sample to be inspected.

  As shown in FIG. 6, the residual stress evaluation apparatus 100 is arranged on the surface of a measurement sample W that is a sample to be inspected, and a transmission probe (transmission unit) 200 that transmits (transmits) ultrasonic waves to the measurement sample W. Similarly, a receiving probe (reception) that is disposed on the surface of the measurement sample W at a position different from that of the transmission probe 200 and receives an ultrasonic wave transmitted from the transmission probe 200 and propagated through the surface layer of the measurement sample W. Part) 300.

  The residual stress evaluation apparatus 100 includes a transmission / reception control unit 110 having both a pulse generator and a transmission / reception amplifier (amplifier). The pulse generator outputs a pulse signal to be supplied to the transmission probe 200. The transmission / reception amplifier amplifies the pulse signal output from the pulse generator and outputs the amplified signal to the transmission probe 200, and collects a reception signal (detection signal) that is an ultrasonic signal received by the reception probe 300. Amplify.

The pulse generator has a configuration corresponding to the pulse generator 4 according to the first embodiment, and is connected to the transmission probe 200 via a transmission / reception amplifier, to the electromagnetic ultrasonic sensor 400a of the transmission probe 200. A current signal (pulse signal) is applied.
The transmission / reception amplifier is an amplifier (amplifier) connected to the transmission probe 200 and the reception probe 300, amplifies the pulse signal generated by the pulse generator, outputs the amplified signal to the transmission probe 200, and receives the signal. The detection signal detected by the electromagnetic ultrasonic sensor 400b of the probe 300 is received, amplified, and output to the signal processing device 120 described later.

That is, the transmission / reception control unit 110 includes the configuration and operation of the waveform sampling device 7 according to the first embodiment.
As shown in FIG. 6, two electromagnet power supplies 130a and 130b are connected to the signal processing device 120, one electromagnet power supply 130a is connected to the transmission probe 200, and the other electromagnet power supply 130b is received. It is connected to the probe 300. The electromagnet power supply 130a is a power supply that supplies current to an electromagnet used in an electromagnetic ultrasonic sensor 400a of the transmission probe 200 described later, and the electromagnet power supply 130b is supplied to an electromagnetic ultrasonic sensor 400b of the reception probe 300 described later. It is a power source that supplies current to the electromagnet used. The signal processing device 120 outputs a trigger signal that is an instruction to supply current to the electromagnets to the electromagnet power supplies 130a and 130b, and stores the time when the trigger signal is output as a transmission time that is an ultrasonic generation time. .

  The residual stress evaluation apparatus 100 includes the signal processing device 120 having the above-described configuration. The signal processing device 120 receives the above-described transmission time indicating the generation time of the ultrasonic wave, and the reception probe 300 receives the detection signal. This is an evaluation device (evaluation unit) that evaluates the residual stress in the propagation path of the ultrasonic wave corresponding to the received signal based on the received time that is the received time. The evaluation of the residual stress performed by the signal processing device 120 is the same process as the evaluation of the residual stress performed by the evaluation unit 8 according to the first embodiment.

  Next, the configuration of the electromagnetic ultrasonic sensor 400 (400a, 400b) used in the transmission probe 200 and the reception probe 300 will be described with reference to FIG. As shown in FIG. 5, the electromagnetic ultrasonic sensor 400a used as the transmission sensor in the transmission probe 200 and the electromagnetic ultrasonic sensor 400b used as the reception sensor in the reception probe 300 have the same configuration. Below, the structure of the electromagnetic ultrasonic sensor 400a used as a transmission sensor is demonstrated.

  As shown in FIG. 5, the electromagnetic ultrasonic sensor 400 a includes, for example, a meandering coil (comb-shaped coil) 410 and two sets of electromagnets A and B. The electromagnetic ultrasonic sensor 400a transmits a surface SH wave by a magnetostriction effect by applying a magnetic field in parallel to the linear portion of the coil 410 formed to meander between the linear portion and the bent portion as shown in FIG. By applying a magnetic field perpendicularly to the straight portion of the coil 410, a Rayleigh wave can be transmitted by the magnetostriction effect.

  The electromagnetic ultrasonic sensor 400 a holds the coil 410 so that the straight portion of the coil 410 is substantially perpendicular to the surface of the measurement sample W, and the electromagnet A of the two sets of electromagnets A and B is the straight line of the coil 410. Are arranged so as to sandwich the coil 410 along the direction parallel to the portion, and, for example, the measurement sample W side has an S pole and the anti-measurement sample W side has an N pole by the power supplied from the electromagnet power supply 130a. Become. Of the two sets of electromagnets A and B, the electromagnet B is disposed so as to sandwich the coil 410 between both ends of the coil 410 along a direction perpendicular to the linear portion of the coil 410, and the above-described electromagnet power supply 130a. The one end side becomes the S pole and the other end side becomes the N pole.

  Such an electromagnetic ultrasonic sensor 400a is known as a so-called magnetostrictive electromagnetic ultrasonic sensor. When a current is supplied to the electromagnet A while the coil 410 is energized, a static magnetic field is generated from the electromagnet A. Thus, a surface SH wave is generated on the surface of the measurement sample W. If a current is supplied to the electromagnet B while the coil 410 is energized, a static magnetic field is generated from the electromagnet B and a Rayleigh wave is generated on the surface of the measurement sample W.

In this way, the transmission probe 200 configured to include the electromagnetic ultrasonic sensor 400a switches the electromagnets A and B that generate a static magnetic field, thereby generating surface SH waves and Rayleigh waves on the surface of the measurement sample W. It can be generated by selectively switching.
The transmission probe 200 includes the above-described electromagnetic ultrasonic sensor 400a at a position that realizes appropriate electromagnetic ultrasonic wave propagation with respect to the surface of the measurement sample W. The reception probe 300 also includes an electromagnetic ultrasonic sensor 400b having a configuration similar to that of the above-described electromagnetic ultrasonic sensor 400a at substantially the same position as the position on the transmission probe 200.

Next, the operation of the residual stress evaluation apparatus 100 including the above-described transmission probe 200 and reception probe 300 will be described.
The transmission probe 200 is arranged on the first position where the ultrasonic wave is incident on the surface of the measurement sample W so that the region for measuring the residual stress is sandwiched, and the reception probe 300 is arranged on the measurement sample. It arrange | positions on the 2nd position which receives a propagation ultrasonic wave on the surface of W.

After this arrangement, the pulse generator of the transmission / reception control unit 110 applies a pulse current to the coil 410 of the electromagnetic ultrasonic sensor 400a of the transmission probe 200.
In a state where a pulse current is applied to the coil 410 of the electromagnetic ultrasonic sensor 400a, the signal processing device 120 outputs a trigger signal corresponding to either the surface SH wave or the Rayleigh wave to the electromagnet power source 130a. At the same time, the signal processing device 120 outputs a similar trigger signal to the electromagnet power supply 130b connected to the reception probe 300, and stores the timing (time etc.) at which the trigger signal is output as the transmission timing.

  When the electromagnet power supply 130a of the transmission probe 200 receives a trigger signal corresponding to the surface SH wave, it supplies a current to the electromagnet A and generates a surface SH wave at the first position on the surface of the measurement sample W. Further, when the electromagnet power supply 130a of the transmission probe 200 receives a trigger signal corresponding to the Rayleigh wave, the electromagnet power supply 130a supplies current to the electromagnet B and generates a Rayleigh wave at the first position on the surface of the measurement sample W. As described above, the electromagnet power supply 130a of the transmission probe 200 first supplies the surface SH wave and Rayleigh wave as a plurality of types of ultrasonic waves having different vibration forms by selectively supplying current to the electromagnet A or the electromagnet B. Is selectively generated at the position.

  On the other hand, when the electromagnet power supply 130b connected to the receiving probe 300 receives a trigger signal corresponding to the surface SH wave, the electromagnet power supply 130b supplies current to the electromagnet A of the electromagnetic ultrasonic sensor 400b of the receiving probe 300, and If a trigger signal corresponding to a wave is received, a current is supplied to the electromagnet B to prepare for reception of the surface SH wave or Rayleigh wave at the second position on the surface of the measurement sample W. This is the sending step and continues to the receiving step.

  The excited propagation wave of the Rayleigh wave or the surface SH wave propagates through the surface layer of the measurement sample W, enters the reception probe 300 from the second position, and enters the electromagnetic ultrasonic sensor 400b of the reception probe 300. To reach. Due to the reception of this propagation ultrasonic wave, the electromagnetic ultrasonic sensor 400b of the reception probe 300 detects an electromotive force in the sensor coil 410 by the vibration of the surface of the object to be inspected and the static magnetic field according to the law of electromagnetic induction and detects it as a received signal. Is done.

The electromagnetic ultrasonic sensor 400 b of the reception probe 300 outputs the electromotive force induced in the coil 410 to the transmission / reception amplifier of the transmission / reception control unit 110. This is the reception step and continues to the evaluation step.
The transmission / reception amplifier amplifies the received propagation ultrasonic wave detection signal and outputs the amplified signal to the signal processing device 120.

The signal processing device 120 receives the detection signal of the propagation ultrasonic wave from the transmission / reception amplifier, and the reception time (time etc.) at which the detection signal is received and the timing (time etc.) at which the propagation ultrasonic wave is transmitted. Based on the above transmission time, the propagation time of the propagation ultrasonic wave is calculated. Since the transmission probe 200 according to the present embodiment cannot generate the Rayleigh wave and the surface SH wave at the same time, the propagation time T _R that is the propagation time of the Rayleigh wave and the propagation time T _S that is the propagation time of the surface SH wave are used. Are calculated separately, and the residual stress σ existing on the surface layer of the measurement sample W propagated by the propagation ultrasonic wave is obtained by the method described in the first embodiment without depending on the propagation distance L of the propagation ultrasonic wave ( evaluate). This is the evaluation step.

In the present embodiment, in order to make the propagation distance L of the surface SH wave and the Rayleigh wave the same, as an example, a method of generating both the surface SH wave and the Rayleigh wave by the electromagnetic ultrasonic sensor 400a which is a magnetostrictive sensor is shown. It was. However, as shown as a modification of the electromagnetic ultrasonic sensor 400a in FIG. 7, the Rayleigh wave can be generated even by a Lorentz type sensor.
FIG. 7 is a diagram showing a schematic configuration of an electromagnetic ultrasonic sensor 400c which is a modification of the electromagnetic ultrasonic sensor 400a.

  The electromagnetic ultrasonic sensor 400c shown in FIG. 7 has the same arrangement and configuration of the coil 410 and the electromagnet A as the electromagnetic ultrasonic sensor 400a shown in FIG. 5, but the arrangement of the electromagnet B is different. The electromagnet B of the electromagnetic ultrasonic sensor 400c is arranged so as to sandwich the coil so as to be substantially parallel to a plane (coil plane) formed by the linear portion of the coil 410. In the electromagnet B, the electromagnet B arranged on one side of the plane of the coil 410 becomes the S pole and the electromagnet B arranged on the other side becomes the N pole by the electric power supplied from the above-described electromagnet power supply 130a.

The electromagnetic ultrasonic sensor 400c having such a configuration generates a surface SH wave by a magnetostrictive type by using the electromagnet A, and generates a Rayleigh wave by a Lorentz type by using the electromagnet B.
Even when the above-described electromagnetic ultrasonic sensor 400c using both the magnetostrictive type and the Lorentz type is used for the transmission probe 200 and the reception probe 300, the propagation distance of the surface SH wave generated in the magnetostrictive type and the Rayleigh generated in the Lorentz type The wave propagation distance is the same.

  Accordingly, the residual stress evaluation apparatus 100 according to the present embodiment can also eliminate the propagation distance L of the propagation ultrasonic wave that easily includes the error and the influence of the contact state of the ultrasonic probe, and therefore depends on the propagation distance L. Without deterioration, it is possible to suppress deterioration in measurement accuracy due to the contact state of the transmission probe 200 and the reception probe 300 with the measurement sample W. Therefore, according to the residual stress evaluation apparatus 100 of the present embodiment, the residual stress existing on the surface layer of the measurement sample W is evaluated (measured) with high accuracy and stability using both the Rayleigh wave and the surface SH wave. be able to.

  Further, the electromagnetic ultrasonic sensors 400 a to 400 c (400) can generate surface SH waves and Rayleigh waves without bringing the transmission probe 200 and the reception probe 300 holding the electromagnetic ultrasonic sensor 400 into contact with the measurement sample W. Can send and receive. Therefore, even if the first position and the second position where the transmission probe 200 and the reception probe 300 are arranged are curved surfaces or rough surfaces, the residual stress existing on the surface layer of the measurement sample W is reduced. Evaluation (measurement) can be performed with high accuracy and high stability.

Finally, according to the principle of reception in electromagnetic ultrasonic waves, the current induced in the coil sandwiched between the electromagnets by the vibration of the surface of the measurement sample W and the static magnetic field from the electromagnet may be detected as the received signal. Therefore, it is not necessary for the receiving probe 300 on the receiving side to have two types of receiving forms in which the arrangement of electromagnets is different in accordance with the driving forms of the surface SH wave and the Rayleigh wave. Therefore, although not shown, the receiving probe 300 on the receiving side may be provided with only one type of spiral coil.
[Fourth Embodiment]
A fourth embodiment of the present invention will be described with reference to FIG.

FIG. 8 is a diagram showing a schematic configuration of a residual stress evaluation apparatus 500 according to the present embodiment.
The residual stress evaluation apparatus 500 according to the present embodiment has substantially the same configuration as the residual stress evaluation apparatus 1 according to the first embodiment, and transmits a transmission probe 800 instead of the transmission probe 2 of the first embodiment. The reception probe 900 is provided as a reception unit instead of the reception probe 3. In the residual stress evaluation apparatus 10 of the present embodiment, the configuration other than the transmission probe 800 and the reception probe 900 is the same as that of the residual stress evaluation apparatus 1 according to the first embodiment.

Hereinafter, the configuration of the transmission probe 800 and the reception probe 900 will be described with reference to FIG. 8, but before that, the premise of the configuration of the transmission probe 800 and the reception probe 900 will be described.
In the first embodiment described above, the SH wave and SV wave transmitted from the transmission probe 2 excite the surface SH wave and Rayleigh wave to propagate the surface layer of the measurement sample W, and the excited surface SH wave and The Rayleigh wave propagates into the reception probe 3. However, in the first embodiment, since the piezoelectric element 30a and the piezoelectric element 30b are stacked, electrical interference may occur rarely. Further, since the excited surface SH wave and Rayleigh wave have different propagation paths, the sound velocity and propagation distance fluctuation between these paths may cause a minute measurement error.

For the reasons described above, the present inventors have conducted various experiments and found that if the SV wave is a short distance, it propagates through the surface layer of the measurement sample W. Good results were also obtained for longitudinal waves.
First, the configuration of the transmission probe 800, which is a feature of this embodiment, will be described with reference to the drawings.
Referring to FIG. 8, a transmission probe 800 as a transmission unit has substantially the same configuration as that of the transmission probe 2 described in the first embodiment, and an ultrasonic wave corresponding to the ultrasonic wave propagation medium 21. A sound wave propagation medium 821 and an ultrasonic wave sending surface 822 corresponding to the ultrasonic wave sending surface 22 are provided, and a piezoelectric element 820 is provided instead of the piezoelectric element 20.

The piezoelectric element 820 is, for example, a flat plate, and is a transmission vibrator different from the piezoelectric element 20, that is, a single transmission vibrator (sixth ultrasonic vibrator) that transmits an SV wave or a longitudinal wave.
When a single transverse wave vibrator is employed for the piezoelectric element 820, when a pulse voltage of a predetermined voltage is applied to the piezoelectric element 820, an SV wave (lateral wave SV wave) having a predetermined frequency is output from the flat plate surface of the piezoelectric element 820. Then, the output transverse wave SV wave is transmitted to the outside through a transmission surface (ultrasonic transmission surface) 822 which is an opening surface formed in the ultrasonic wave propagation medium 821 of the transmission probe 800.

On the other hand, when a single longitudinal wave vibrator is employed for the piezoelectric element 820, when a predetermined pulse voltage is applied to the piezoelectric element 820, a longitudinal wave having a predetermined frequency is output from the flat plate surface of the piezoelectric element 820, The output longitudinal wave is transmitted to the outside through a transmission surface (ultrasonic transmission surface) 822 which is an opening surface formed in the ultrasonic propagation medium 821 of the transmission probe 800.
The operation of the transmission probe 800 will be described with reference to FIG. When the transmission probe 800 is disposed on the surface of the measurement sample W with the ultrasonic transmission surface 822 being in contact with the surface of the measurement sample W, the piezoelectric element 820 of the transmission probe 800 has the ultrasonic transmission surface 822. It is arranged so as to be inclined with respect to the surface of the measurement sample W by the same angle with respect to.

  When a single transverse wave vibrator is adopted as the piezoelectric element 820, when a pulse voltage is applied from the pulse generator 4 to the piezoelectric element 820, the piezoelectric element 820 has a predetermined frequency according to the applied pulse voltage. The transverse wave SV is output. The transverse wave SV output from the output surface of the piezoelectric element 20 is transmitted in an oblique direction with respect to the first position on the surface of the measurement sample W through the ultrasonic transmission surface 822 of the transmission probe 800.

The transmitted transverse wave SV is incident obliquely with respect to the first position on the surface of the measurement sample W, and excites a plurality of types of ultrasonic waves having different vibration forms on the surface layer of the measurement sample W. As shown in FIG. 8, the transverse SV wave incident obliquely on the surface of the measurement sample W excites the surface SV wave (broken line in FIG. 8) and the Rayleigh wave (solid line in FIG. 8) simultaneously.
On the other hand, when a single longitudinal wave vibrator is adopted as the piezoelectric element 820, the piezoelectric element 820 outputs a longitudinal wave having a predetermined frequency by the applied pulse voltage. The output longitudinal wave is sent in an oblique direction with respect to the first position on the surface of the measurement sample W through the ultrasonic wave sending surface 822. The transmitted longitudinal wave is incident obliquely with respect to the first position on the surface of the measurement sample W, and surface SV waves (broken lines in FIG. 8) and Rayleigh waves (FIG. 8) are formed on the surface layer of the measurement sample W. (Solid line in the middle) is excited simultaneously.

In summary, the transmission probe 800 is arranged on the surface of the measurement sample W that is a sample to be inspected, and sends a single ultrasonic wave (a transverse wave SV wave or a longitudinal wave) to the surface layer of the measurement sample W. Thus, the surface SV wave and the Rayleigh wave (plural types of propagating ultrasonic waves having different vibration forms) are simultaneously excited on the surface layer of the measurement sample W.
Next, the configuration of the reception probe 900, which is a feature of the present embodiment, will be described with reference to the drawings.

Referring to FIG. 8, a reception probe 900 that is a reception unit has substantially the same configuration as that of the reception probe 3 described in the first embodiment, and an ultrasonic wave corresponding to the ultrasonic propagation medium 31. A sound wave propagation medium 931 (for example, polystyrene) and an ultrasonic wave incident surface 932 corresponding to the ultrasonic wave incident surface 32 are provided, and a piezoelectric element 930 is provided instead of the piezoelectric element 30.
The ultrasonic propagation medium 931 converts the surface SV wave and Rayleigh wave propagated through the surface layer of the measurement sample W into a transverse wave SV or a longitudinal wave.

The piezoelectric element 930 is, for example, a flat plate, and is a receiving vibrator different from the piezoelectric element 30, that is, a single receiving vibrator (first receiving vibrator for receiving a transverse wave SV wave or a longitudinal wave converted by the ultrasonic wave propagation medium 931). 7 ultrasonic transducer).
The reception probe 900 including such a piezoelectric element 930 receives the transverse wave SV wave or longitudinal wave emitted from the piezoelectric element 930 from the second position and converted by the ultrasonic wave propagation medium 931 substantially vertically. Is arranged.

The operation of the reception probe 900 will be described with reference to FIG.
When a single transverse wave vibrator is adopted for the piezoelectric element 820 and a single longitudinal wave vibrator is adopted for the piezoelectric element 930, the reception probe 900 is excited by the transverse wave SV wave sent from the transmission probe 800. The propagated Rayleigh wave and surface SV wave are converted into a longitudinal wave by the ultrasonic wave propagation medium 931, the longitudinal wave is received by the piezoelectric element 930, and is output to the amplifier 600 as a longitudinal wave detection signal.

Specifically, the Rayleigh wave and the surface SV wave propagated through the surface layer of the measurement sample W propagate from the ultrasonic incident surface 931 of the reception probe 900 into the reception probe 900 and are transmitted by the ultrasonic propagation medium 931. It is converted into a longitudinal wave and enters the flat plate surface of the piezoelectric element 930 that faces the ultrasonic wave incident surface 931. The incident longitudinal wave is detected by the piezoelectric element 930 which is a single longitudinal wave vibrator.
By adopting a single longitudinal wave vibrator for the piezoelectric element 820, Rayleigh waves and surface SV waves can be propagated. Also, in reception, these ultrasonic waves are converted into transverse SV waves in the ultrasonic wave propagation medium 931. Through the conversion, a transverse wave SV wave can be detected by the transverse wave detection piezoelectric element 930.

An operation of the residual stress evaluation apparatus 500 including the above-described transmission probe 800 and reception probe 900 will be described. An example in which a single transverse wave vibrator is employed for the piezoelectric element 820 of the transmission probe 800 and a single longitudinal wave vibrator is employed for the piezoelectric element 930 of the reception probe 900 is taken as an example. explain.
The transmission probe 800 disposed on the surface of the measurement sample W sends the transverse wave SV wave output from the piezoelectric element 820 to the first position on the surface of the measurement sample W. The transmitted transverse wave SV excites the Rayleigh wave and the surface SV wave simultaneously on the surface layer of the measurement sample W. This is the sending step.

The receiving probe 900 converts the excited Rayleigh wave and surface SV wave into a longitudinal wave by the ultrasonic wave propagation medium 931, receives the longitudinal wave by the piezoelectric element 930, and receives the longitudinal wave detection signal by the amplifier 600. Output to. This is the reception step. Since the evaluation step and subsequent steps are the same as those in the first embodiment, description thereof will be omitted.
On the other hand, when a single longitudinal wave vibrator is adopted for the piezoelectric element 820 of the transmission probe 800 and a single transverse wave vibrator is adopted for the piezoelectric element 930 of the reception probe 900, the longitudinal wave is transmitted from the piezoelectric element 820. The transmitted longitudinal wave excites the Rayleigh wave and the surface SV wave, and converts the Rayleigh wave and the surface SV wave excited by the ultrasonic wave propagation medium 931 into a longitudinal wave.

  Also with the residual stress evaluation apparatus 500 of the present embodiment, the propagation distance L of the propagation ultrasonic wave that is likely to include the error and the influence of the contact state of the ultrasonic probe can be excluded, so that it does not depend on the propagation distance L. Therefore, it is possible to suppress deterioration in measurement accuracy due to the contact state of the transmission probe 800 and the reception probe 900 with the measurement sample W. Therefore, according to the residual stress evaluation apparatus 500 of the present embodiment, the residual stress existing on the surface layer of the measurement sample W is evaluated (measured) with high accuracy and stability using both the Rayleigh wave and the surface SV wave. be able to. Moreover, according to the residual stress evaluation apparatus 500 having the above-described configuration, it is possible to suppress a minute measurement error due to electrical interference between the ultrasonic waves, sound speed between ultrasonic propagation paths, and propagation distance fluctuation.

  Each embodiment disclosed this time should be considered as illustrative in all points and not restrictive. In particular, in each embodiment disclosed this time, matters that are not explicitly disclosed, for example, operating conditions and operating conditions, various parameters, dimensions, weights, volumes, etc. of the constituents are within the range normally practiced by those skilled in the art. It does not deviate and employs a value that can be easily assumed by those skilled in the art.

  Specifically, in the residual stress evaluation apparatus 1 according to the first embodiment, the transmission probe 2 outputs the SH wave and the SV wave at the same time, excites the Rayleigh wave and the surface SH wave at the same time, and the reception probe 3 The Rayleigh wave and the surface SH wave were received simultaneously. However, the transmission probe 2 may output the SH wave and the SV wave separately instead of simultaneously, and the reception probe 3 may receive the Rayleigh wave and the surface SH wave separately instead of simultaneously. Even if the ultrasonic waves are transmitted and received separately, the propagation paths of the Rayleigh wave and the surface SH wave are the same, so the residual stress existing in the surface layer of the measurement sample W can be evaluated according to the above-described equation (3).

1, 10, 100, 500 Residual stress evaluation device 2, 2a, 200, 800 Transmitting probe 3, 9, 300, 900 Reception probe 4 Pulse generator 5, 6,600 Amplifier 7 Waveform sampling device 8 Evaluation device 20, 20a, 20b, 820 Piezoelectric element
21, 21a, 31, 91, 821, 931 Ultrasonic propagation medium 22, 22a, 822 Ultrasonic transmission surface 30, 30a, 30b, 90, 90a, 90b, 930 Piezoelectric element 32, 92, 932 Ultrasonic incident surface 110 Transmission / reception Control unit 120 Signal processing device 130a, 130b Electromagnet power supply 400a, 400b, 400c Electromagnetic ultrasonic sensor 410 Coil W Measurement sample

Claims (19)

A residual stress evaluation method for evaluating a residual stress existing in a surface layer of an object sample based on a propagation time of an ultrasonic wave propagating through the surface layer of the object sample,
Sending out a plurality of types of ultrasonic waves having different vibration forms to the surface layer of the sample to be inspected by sending a plurality of types of ultrasonic waves having different vibration forms to the surface layer of the sample to be inspected;
A receiving step of receiving the plurality of types of propagating ultrasonic waves propagating through the surface layer of the sample to be inspected;
Calculating a propagation time of each of the plurality of types of propagation ultrasonic waves received in the receiving step, and evaluating the residual stress based on the calculated propagation time; Evaluation method. The sending step sends the plurality of types of ultrasonic waves to a first position on the surface of the subject sample,
2. The residual stress according to claim 1, wherein the receiving step receives the plurality of types of propagation ultrasonic waves from a second position different from the first position on the surface of the subject sample. Evaluation method.   The residual stress evaluation method according to claim 1 or 2, wherein the plurality of types of propagating ultrasonic waves received in the receiving step are Rayleigh waves and surface SH waves. The sending step sends SH waves and SV waves as the plurality of types of ultrasonic waves,
The receiving step receives the Rayleigh wave and the surface SH wave propagated by being excited by the SH wave and SV wave transmitted in the transmitting step as the plurality of types of propagating ultrasonic waves. The residual stress evaluation method according to 2.   5. The receiving step receives the Rayleigh wave and the surface SH wave at different positions according to the outgoing angles of the propagated Rayleigh wave and the surface SH wave from the second position, respectively. The residual stress evaluation method described in 1.   The residual stress evaluation method according to claim 5, wherein the receiving step detects the Rayleigh wave as a longitudinal wave and detects the surface SH wave as a transverse wave.   The residual stress evaluation method according to claim 1 or 2, wherein the plurality of types of propagating ultrasonic waves received in the receiving step are Rayleigh waves and surface SV waves. A mode in which the sending step excites a Rayleigh wave and a surface SV wave as the plurality of kinds of propagating ultrasonic waves to the sample to be inspected by sending a longitudinal wave or an SV wave from a longitudinal vibrator or a transverse oscillator. And
8. The residual stress evaluation method according to claim 7, wherein the receiving step receives the reception of the Rayleigh wave and the surface SV wave propagated by excitation with a single longitudinal wave or transverse wave vibrator. A residual stress evaluation apparatus that evaluates residual stress existing in a surface layer of a specimen sample based on a propagation time of an ultrasonic wave propagating through the surface layer of the specimen sample,
Sending out a plurality of types of ultrasonic waves having different vibration forms to the surface layer of the sample to be inspected, thereby exciting a plurality of types of propagation ultrasonic waves having different vibration forms to the surface layer of the sample to be inspected,
A receiving unit for receiving the plurality of types of propagation ultrasonic waves propagating on the surface layer of the sample to be inspected;
A residual stress, comprising: an evaluation unit that calculates a propagation time of each of a plurality of types of propagation ultrasonic waves received by the receiving unit, and evaluates the residual stress based on the calculated propagation time. Evaluation device. The delivery unit sends the plurality of types of ultrasonic waves to a first position on the surface of the subject sample;
10. The residual stress according to claim 9, wherein the receiving unit receives the plurality of types of propagation ultrasonic waves from a second position on a surface of the subject sample different from the first position. Evaluation device. The sending unit has a single first ultrasonic transducer for sending the plurality of types of ultrasonic waves,
The residual stress evaluation apparatus according to claim 9 or 10, wherein the reception unit includes a single first ultrasonic transducer that receives the plurality of types of propagation ultrasonic waves.   The residual stress evaluation apparatus according to claim 9, wherein the plurality of types of propagation ultrasonic waves received by the receiving unit are Rayleigh waves and surface SH waves. The sending unit sends out SH waves and SV waves as the plurality of types of ultrasonic waves,
The receiving unit receives, as the plurality of types of propagation ultrasonic waves, Rayleigh waves and surface SH waves that are propagated by being excited by SH waves and SV waves transmitted by the transmitting unit. The residual stress evaluation apparatus according to any one of 11. The sending unit has a single first ultrasonic transducer for sending the plurality of types of ultrasonic waves,
A second ultrasonic transducer configured to receive the Rayleigh wave provided at a position corresponding to an outgoing angle of the propagated Rayleigh wave from the second position; and the second ultrasonic transducer; Is a different ultrasonic transducer, and is provided at a position corresponding to an outgoing angle of the propagated surface SH wave from the second position, and receives a third ultrasonic transducer. The residual stress evaluation apparatus according to claim 9 or 10, characterized in that The transmitting unit is a fourth ultrasonic transducer for transmitting SV waves to the first position, and an ultrasonic transducer for transmitting ultrasonic waves at an angle different from the fourth ultrasonic transducer, A fifth ultrasonic transducer for sending the SH wave to a first position;
A second ultrasonic transducer configured to receive the Rayleigh wave provided at a position corresponding to an outgoing angle of the propagated Rayleigh wave from the second position; and the second ultrasonic transducer; Is a different ultrasonic transducer, and is provided at a position corresponding to an outgoing angle of the propagated surface SH wave from the second position, and receives a third ultrasonic transducer. The residual stress evaluation apparatus according to claim 9 or 10, characterized in that The second ultrasonic transducer receives the Rayleigh wave as a longitudinal wave;
The residual stress evaluation apparatus according to claim 14 or 15, wherein the third ultrasonic transducer receives the SH wave as a transverse wave. The delivery unit is composed of an electromagnetic ultrasonic sensor,
The residual stress evaluation apparatus according to claim 9, wherein the receiving unit is configured by an electromagnetic ultrasonic sensor.   The residual stress evaluation apparatus according to claim 9, wherein the plurality of types of propagation ultrasonic waves received by the receiving unit are Rayleigh waves and surface SV waves. The sending unit is composed of a single oscillator of longitudinal waves or transverse waves,
The residual stress evaluation apparatus according to claim 18, wherein the receiving unit is configured by a single oscillator of a longitudinal wave or a transverse wave.