KR20020050833A - Apparatus and method of noncontact measurement of crystal grain size - Google Patents

Apparatus and method of noncontact measurement of crystal grain size Download PDF

Info

Publication number
KR20020050833A
KR20020050833A KR1020000080017A KR20000080017A KR20020050833A KR 20020050833 A KR20020050833 A KR 20020050833A KR 1020000080017 A KR1020000080017 A KR 1020000080017A KR 20000080017 A KR20000080017 A KR 20000080017A KR 20020050833 A KR20020050833 A KR 20020050833A
Authority
KR
South Korea
Prior art keywords
grain size
laser
measured
reflected
light
Prior art date
Application number
KR1020000080017A
Other languages
Korean (ko)
Other versions
KR100496826B1 (en
Inventor
김달우
임충수
홍순택
Original Assignee
신현준
재단법인 포항산업과학연구원
이구택
주식회사 포스코
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 신현준, 재단법인 포항산업과학연구원, 이구택, 주식회사 포스코 filed Critical 신현준
Priority to KR10-2000-0080017A priority Critical patent/KR100496826B1/en
Publication of KR20020050833A publication Critical patent/KR20020050833A/en
Application granted granted Critical
Publication of KR100496826B1 publication Critical patent/KR100496826B1/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/043—Analysing solids in the interior, e.g. by shear waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/11—Analysing solids by measuring attenuation of acoustic waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/22—Details, e.g. general constructional or apparatus details
    • G01N29/24—Probes
    • G01N29/2418—Probes using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
    • G01N29/4472—Mathematical theories or simulation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/028—Material parameters
    • G01N2291/0289—Internal structure, e.g. defects, grain size, texture

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Chemical & Material Sciences (AREA)
  • Pathology (AREA)
  • General Health & Medical Sciences (AREA)
  • Biochemistry (AREA)
  • Analytical Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Acoustics & Sound (AREA)
  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Mathematical Analysis (AREA)
  • Pure & Applied Mathematics (AREA)
  • Algebra (AREA)
  • Mathematical Physics (AREA)
  • Mathematical Optimization (AREA)
  • Optics & Photonics (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

PURPOSE: A non-contact type apparatus and method is provided to measure the crystal particle diameter on an on-line basis, regardless of the state of the object being measured, and environment. CONSTITUTION: An apparatus comprises a pulse type high output laser unit(1) for radiating a laser beam to one surface of an object to be measured, such that the surface temperature of the surface of the object is quickly raised so as to cause an instantaneous adiabatic expansion and generate an ultrasonic wave; a continuous oscillating laser unit(9) for radiating a laser beam to the other surface of the object, such that laser beam is reflected by the ultrasonic wave generated from the pulse type high output laser; a Fabry-Perot interferometer(10) for interfering only the laser beam radiated from the other surface of the object, from among the laser beam radiated by the continuous oscillating laser unit; an optical detector(11) for detecting an ultrasonic signal by the laser beam interfered by the Fabry-Perot interferometer; and a computing unit(12) for computing the attenuation coefficient of ultrasonic wave in accordance with the ultrasonic signal detected by the optical detector.

Description

비접촉식 결정입경 측정장치 및 방법{Apparatus and method of noncontact measurement of crystal grain size}Apparatus and method of noncontact measurement of crystal grain size}

본 발명은 결정입경 측정장치에 관한 것이며, 특히, 레이저를 이용한 광학적 간섭방법으로 측정 대상물에 비접촉식으로 초음파를 발생시켜 초음파의 감쇄계수를측정하고 그에 따라 결정입경을 측정하는 비접촉식 결정입경 측정장치에 관한 것이다. 또한, 본 발명은 레이저를 이용한 광학적 간섭방법으로 측정 대상물에 비접촉식으로 초음파를 발생시켜 초음파의 감쇄계수를 측정하고 그에 따라 결정입경을 측정하는 비접촉식 결정입경 측정방법에 관한 것이기도 하다.The present invention relates to an apparatus for measuring grain size, and more particularly, to a non-contact grain size measuring apparatus for measuring ultrasonic wave attenuation coefficients by measuring ultrasonic attenuation coefficients by generating ultrasonic waves in a non-contact manner to an object to be measured by an optical interference method using a laser. will be. In addition, the present invention also relates to a non-contact crystal grain size measuring method for measuring the attenuation coefficient of the ultrasonic wave by generating an ultrasonic wave in a non-contact manner to the object to be measured by the optical interference method using a laser accordingly.

제철분야에서 압연제어기술의 발전에 따라 동일한 성분 조성을 갖는 물질을 통해 다양한 종류의 열연강판을 생산하는 것이 가능하다. 이와 같이 압연제어를 통해 원하는 종류의 강판을 생산하기 위해서는 강판의 결정입경의 크기를 생산라인에서 온-라인으로 계측하는 것이 필요하다.With the development of rolling control technology in the field of steelmaking, it is possible to produce various kinds of hot rolled steel sheets through materials having the same composition. As such, in order to produce a desired type of steel sheet through rolling control, it is necessary to measure the grain size of the steel sheet on-line in the production line.

결정입경의 크기를 측정하는 방법으로는 결정입자의 경계를 화학약품으로 부식시켜 광학현미경으로 관찰하는 것이 일반적이지만 이 방법은 시편을 샘플링하여 오프-라인으로 측정하는데 적합하다. 또다른 방법으로는 초음파를 강판에 입사시켜 강판 내부에서 전파하는 초음파의 감쇄특성을 이용하여 결정입자의 크기를 측정할 수가 있다. 이러한 초음파를 이용한 특성평가는 측정대상을 변형시키지 않는 비파괴 검사이기 때문에 온-라인 계측방식으로 적절한 방법이다. 그러나, 생산라인에서 고속으로 이동하는 강판을 측정대상으로 할 경우에는 초음파의 발진 및 검지가 비접촉식으로 이루어져야 하며 이는 기존의 압전소자를 이용한 변환기(transducer) 방식으로는 실현이 불가능하다.As a method of measuring the grain size, it is common to observe the boundary of crystal grains with a chemical microscope and observe them with an optical microscope, but this method is suitable for sampling and measuring off-line. As another method, the size of the crystal grains can be measured by using the attenuation characteristics of the ultrasonic waves that enter the steel sheet and propagate in the steel sheet. The characterization using ultrasonic waves is a non-destructive test that does not deform the measurement object, and thus is an appropriate method for on-line measurement. However, when the steel sheet moving at a high speed in the production line as the measurement target, the ultrasonic wave oscillation and detection should be made in a non-contact type, which cannot be realized by a conventional transducer method using a piezoelectric element.

따라서, 본 발명은 앞서 설명한 바와 같은 종래기술의 문제점을 해결하기 위하여 안출된 것으로서, 레이저를 이용한 광학적 간섭방법으로 초음파를 비접촉방식으로 발생시켜 측정 대상물의 초음파 감쇄계수를 측정하고 그에 따라 결정입경을 측정함으로써, 측정 대상물의 상태 및 주변환경에 무관하게 측정 대상물의 결정입경을 측정하는 장치 및 방법을 제공하는데 그 목적이 있다.Accordingly, the present invention has been made to solve the problems of the prior art as described above, by generating the ultrasonic wave in a non-contact method by the optical interference method using a laser to measure the ultrasonic attenuation coefficient of the measurement target and to measure the crystal grain size accordingly It is an object of the present invention to provide an apparatus and a method for measuring the crystal grain size of a measurement target regardless of the state of the measurement target and the surrounding environment.

도 1은 본 발명의 한 실시예에 따른 비접촉식 결정입경 측정장치의 개략적인 구성도이고,1 is a schematic configuration diagram of a non-contact grain size measuring apparatus according to an embodiment of the present invention,

도 2는 도 1에 도시된 비접촉식 결정입경 측정장치를 사용하여 결정입경을 측정한 그래프이다.FIG. 2 is a graph measuring grain size using the non-contact grain size measuring apparatus shown in FIG. 1.

♠ 도면의 주요부분에 대한 부호의 설명 ♠♠ Explanation of symbols on the main parts of the drawing ♠

1 : 펄스형 고출력 레이저 2, 7, 8 : 거울1: pulse type high power laser 2, 7, 8: mirror

3, 5 : 볼록렌즈 4 : 시편3, 5: convex lens 4: specimen

6 : 오목렌즈 9 : 연속발진 레이저6 concave lens 9 continuous oscillation laser

10 : 패브리-페로 간섭계 11 : 광검지기10: Fabry-Perot interferometer 11: Light detector

12 : 연산장치12: computing device

위와 같은 목적을 달성하기 위한 본 발명의 결정입경 측정장치는, 측정 대상물의 한 쪽의 표면 온도를 급격히 상승시키고 순간적인 단열팽창을 일으켜 초음파가 발생하도록 측정 대상물의 한 쪽의 표면에 레이저 광선을 조사하는 제1 레이저와, 상기 제1 레이저에 의해 발생된 초음파에 의해 광선이 반사되도록 측정 대상물의 다른 쪽의 표면에 레이저 광선을 조사하는 제2 레이저와, 상기 제2 레이저에 의해 반사된 광선 중 측정 대상물의 다른 쪽의 표면에서 반사된 광선만을 간섭시키는 패브리-페로 간섭계와, 상기 패브리-페로 간섭계에서 간섭된 광선으로 초음파 신호를 검지하는 광검지기 및, 상기 광검지기에서 검지한 초음파 신호에 따라 초음파의 감쇄계수를 계산하는 연산장치를 포함하는 것을 특징으로 한다.In order to achieve the above object, the crystal grain size measuring apparatus of the present invention irradiates a laser beam to one surface of the measurement target so that ultrasonic waves are generated by rapidly increasing the surface temperature of one side of the measurement target and causing instantaneous adiabatic expansion. A first laser, a second laser for irradiating a laser beam to the other surface of the measurement object such that the light is reflected by the ultrasonic waves generated by the first laser, and a light beam reflected by the second laser A Fabry-Perot interferometer that only interferes with the rays reflected from the other surface of the object, an optical detector for detecting an ultrasonic signal with the rays interfered with the Fabry-Perot interferometer, and an ultrasonic wave according to the ultrasonic signal detected by the photodetector. And an arithmetic device for calculating the attenuation coefficient.

또한, 본 발명의 결정입경 측정방법은, 측정 대상물의 한 쪽의 표면 온도를 급격히 상승시키고 순간적인 단열팽창을 일으켜 초음파가 발생하도록 측정 대상물의 한 쪽의 표면에 레이저 광선을 조사하는 제1 조사단계와, 상기 제1 조사단계에 의해 발생된 초음파에 의해 광선이 반사되도록 측정 대상물의 다른 쪽의 표면에 레이저 광선을 조사하는 제2 조사단계와, 상기 제2 조사단계에 의해 반사된 광선 중 측정 대상물의 다른 쪽의 표면에서 반사된 광선만을 간섭시키는 간섭단계와, 상기 간섭단계에서 간섭된 광선으로 초음파 신호를 검지하는 검지단계 및, 상기 검지단계에서 검지한 초음파 신호에 따라 초음파의 감쇄계수를 계산하는 연산단계를 포함하는 것을 특징으로 한다.In addition, in the crystal grain size measuring method of the present invention, a first irradiation step of irradiating a laser beam to one surface of the measurement target to rapidly increase the surface temperature of one side of the measurement target and to cause instantaneous adiabatic expansion to generate ultrasonic waves And a second irradiation step of irradiating a laser beam to the other surface of the measurement object such that the light beam is reflected by the ultrasonic waves generated by the first irradiation step, and the measurement object among the light beams reflected by the second irradiation step. An interference step of interfering only the light rays reflected from the other surface of the detection step, a detection step of detecting an ultrasonic signal with the light beams interfered in the interference step, and calculating an attenuation coefficient of the ultrasonic wave according to the ultrasonic signal detected in the detection step Characterized in that it comprises a calculation step.

아래에서, 본 발명에 따른 비접촉식 결정입경 측정장치 및 방법의 양호한 실시예를 첨부한 도면을 참조로 하여 상세히 설명하겠다.Hereinafter, with reference to the accompanying drawings, a preferred embodiment of a non-contact grain size measuring apparatus and method according to the present invention will be described in detail.

도 1은 본 발명의 한 실시예에 따른 비접촉식 결정입경 측정장치의 개략적인 구성도이다. 도 1에 보이듯이, 본 발명의 장치는 초음파의 발진을 위해 펄스형 고출력 레이저(1)를 사용한다. 이런 펄스형 고출력 레이저(1)에 발진되는 펄스 빔은 거울(2)에 의해 원하는 방향으로 진행 방향이 결정된 후 볼록렌즈(3)에 의해 집광되어 시편(4)의 한 쪽의 표면에 입사하여 초음파를 발생시킨다. 즉, 시간적으로 짧은 펄스 폭을 갖는 펄스형 고출력 레이저(1)에서 발진된 펄스 빔이 측정 대상물의 시편(4)의 표면에 부딪쳐 표면 온도를 급격히 상승시킨 후 순간적으로 단열팽창을 일으켜 초음파를 발생시키는 것이다. 이런 초음파에 의해 시편(4)의 표면에서는 국소적인 표면변위가 발생하게 된다.1 is a schematic configuration diagram of a non-contact grain size measuring apparatus according to an embodiment of the present invention. As shown in Fig. 1, the apparatus of the present invention uses a pulsed high power laser 1 for the oscillation of ultrasonic waves. The pulse beam oscillated by such a pulsed high power laser 1 is focused by a convex lens 3 after the advancing direction is determined by a mirror 2 in a desired direction, and is incident on one surface of the specimen 4 by ultrasonic wave. Generates. That is, the pulse beam oscillated by the pulsed high power laser 1 having a short pulse width in time hits the surface of the specimen 4 of the measurement object and rapidly raises the surface temperature, and instantaneously causes adiabatic expansion to generate ultrasonic waves. will be. This ultrasonic wave causes local surface displacement on the surface of the specimen 4.

이렇게 발생된 초음파를 본 발명에서는 시편(4)의 표면에서 패브리-페로 간섭계(10)를 이용하여 측정하는 것이다. 이를 위해 본 발명에서는 연속발진 레이저(9)에서 발진된 광선을 거울(8)로 반사시켜 측정하고자 하는 시편(4)의 다른 쪽의 표면에 입사시킨다. 이렇게 입사된 광선은 시편(4)에서 국부적으로 발생하는 표면변위에 따라 반사하는데, 이렇게 반사된 광선은 볼록렌즈(5)에 의해 집광된 후 오목렌즈(6)를 통과한 후 평행광선이 되어 거울(7)에서 반사되어 패브리-페로 간섭계(10)에 입사된다. 이런 간섭계(10)는 주파수 영역이 매우 넓으므로 초음파의 주파수에 따른 신호의 왜곡이 없어 데이터 해석을 위한 신호처리가 매우 용이한 특징이 있다.The ultrasonic waves thus generated are measured using a Fabry-Perot interferometer 10 on the surface of the specimen 4. To this end, in the present invention, the light beam oscillated by the continuous oscillation laser 9 is reflected by the mirror 8 and incident on the surface of the other side of the specimen 4 to be measured. The incident light is reflected according to the surface displacement locally occurring in the specimen 4, and the reflected light is collected by the convex lens 5, passes through the concave lens 6, and becomes a parallel light beam. Reflected at (7) is incident on the Fabry-Perot interferometer (10). Since the interferometer 10 has a very wide frequency domain, there is no distortion of the signal according to the frequency of the ultrasonic wave, so the signal processing for data analysis is very easy.

이런 특징을 갖는 패브리-페로 간섭계(10)로 입사된 광선 중 시편(4)에서 반사되어 입사한 광선은 패브리-페로 간섭계(10) 내에서 왕복하며 간섭을 일으킨다. 그 결과 간섭계(10)를 통과한 빛은 광검지기(11)에서 초음파 신호가 검지되고, 이렇게 검지된 신호에 따라 연산장치(12)는 초음파의 감쇄계수를 계산하고, 그 결과를 사용하여 결정입경을 구하게 된다.Of the light rays incident on the Fabry-Perot interferometer 10 having this characteristic, the light rays reflected by the specimen 4 and incident therebetween reciprocate and cause interference in the Fabry-Perot interferometer 10. As a result, the light passing through the interferometer 10 is detected by an ultrasonic signal in the photodetector 11, and the arithmetic unit 12 calculates the attenuation coefficient of the ultrasonic wave according to the detected signal, and uses the result to determine the crystal grain size. Will be obtained.

초음파의 감쇄계수(α)는 다음의 수학식 1을 이용하여 구할 수 있다.The attenuation coefficient α of the ultrasonic wave can be obtained by using Equation 1 below.

여기서 l 은 시편의 두께를 나타내고, B와 C는 각각 초음파가 시편 내부를 한 번 및 두 번 왕복한 후의 세기를 나타내며, R은 시편 내부의 초음파가 경계면(시편 표면)에서 반사될 때의 반사율을 나타낸다.Where l represents the thickness of the specimen, B and C represent the intensity after ultrasonic waves have reciprocated once and twice inside the specimen, and R is the reflectance when the ultrasonic waves within the specimen are reflected at the interface (surface). Indicates.

도 2는 도 1에 도시된 비접촉식 결정입경 측정장치를 사용하여 결정입경을 측정한 그래프로서, 결정입경의 크기가 다른 여러 개의 시편을 대상으로 감쇄계수(α)를 측정한 결과와 현미경으로 관찰한 결정입경의 크기를 비교한 것이다.FIG. 2 is a graph measuring the crystal grain size using the non-contact grain size measuring apparatus shown in FIG. 1. The attenuation coefficient (α) of a plurality of specimens having different grain sizes is measured and observed with a microscope. The size of the grain size is compared.

도 2에서 알 수 있듯이, 측정결과 결정입경의 증가에 따라 감쇄계수(α)가 증가하는데, 결정입경의 크기는 초음파의 감쇄계수(α)와 선형적인 비례관계가 있음을 알 수 있다.As can be seen in Figure 2, the attenuation coefficient (α) increases as the crystal grain size increases as a result of the measurement, it can be seen that the size of the crystal grain has a linear proportional relationship with the attenuation coefficient (α) of the ultrasonic wave.

따라서, 상기와 같이 구성된 본 발명의 비접촉식 결정입경 측정장치 및 방법은 레이저를 이용한 광학적 간섭방법으로 초음파을 발진 및 검지하는 비접촉방식으로 측정 대상물의 감쇄계수(α)를 계산하고, 그 감쇄계수(α)를 통해 측정 대상물의 결정입경을 구할 수 있는 것이다.Therefore, the non-contact crystal grain size measuring apparatus and method of the present invention configured as described above calculates the attenuation coefficient α of the measurement target in a non-contact method of oscillating and detecting ultrasonic waves by an optical interference method using a laser, and the attenuation coefficient α. Through this, the crystal grain size of the measurement object can be obtained.

즉, 본 발명의 비접촉식 결정입경 측정장치 및 방법을 이용하여 측정 대상물의 결정입경의 크기를 비접촉식 및 비파괴식으로 측정 대상물의 상태 및 주변환경에 무관하게 온-라인으로 측정할 수가 있다.That is, using the non-contact grain size measuring apparatus and method of the present invention, the size of the grain size of the measurement object can be measured on-line irrespective of the state of the measurement object and the surrounding environment in a non-contact and non-destructive manner.

앞서 상세히 설명한 바와 같이 본 발명의 비접촉식 결정입경 측정장치 및 방법은 레이저를 이용한 광학적 간섭방법으로 측정 대상물의 결정입경의 크기를 비접촉식 및 비파괴식으로 측정 대상물의 상태 및 주변환경에 무관하게 온-라인으로 측정하는 효과가 있다.As described in detail above, the non-contact crystal grain size measuring apparatus and method of the present invention is an optical interference method using a laser, and the size of the grain size of the measurement object is non-contact and non-destructive, on-line regardless of the state and surrounding environment of the measurement object. It is effective to measure.

또한, 본 발명의 비접촉식 결정입경 측정장치는 측정 대상물로부터 멀리 떨어진 지점에서의 원격측정이 가능하기 때문에, 열악한 주변환경에 있는 측정 대상물의 측정시에도 그 보호가 용이할 뿐만 아니라 높은 현장 적용성을 갖는 장점이 있다.In addition, since the non-contact grain size measuring apparatus of the present invention can be remotely measured at a point far from the measurement object, it is easy to protect the measurement object even in poor surroundings and has high field applicability. There is an advantage.

이상에서 본 발명의 비접촉식 결정입경 측정장치 및 방법에 대한 기술사항을 첨부도면과 함께 서술하였지만 이는 본 발명의 가장 양호한 실시예를 예시적으로 설명한 것이지 본 발명을 한정하는 것은 아니다.Although the technical details of the non-contact grain size measuring apparatus and method of the present invention have been described together with the accompanying drawings, the present invention has been described by way of example and is not intended to limit the present invention.

또한, 이 기술분야의 통상의 지식을 가진 자이면 누구나 본 발명의 기술사상의 범주를 이탈하지 않는 범위내에서 다양한 변형 및 모방이 가능함은 명백한 사실이다.In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

Claims (4)

초음파를 이용하여 측정 대상물의 결정입경의 크기를 측정하는 결정입경 측정장치에 있어서,In the crystal grain size measuring apparatus for measuring the size of the crystal grain size of the object to be measured using ultrasonic waves, 측정 대상물의 한 쪽의 표면 온도를 급격히 상승시키고 순간적인 단열팽창을 일으켜 초음파가 발생하도록 측정 대상물의 한 쪽의 표면에 레이저 광선을 조사하는 제1 레이저와, 상기 제1 레이저에 의해 발생된 초음파에 의해 광선이 반사되도록 측정 대상물의 다른 쪽의 표면에 레이저 광선을 조사하는 제2 레이저와, 상기 제2 레이저에 의해 반사된 광선 중 측정 대상물의 다른 쪽의 표면에서 반사된 광선만을 간섭시키는 패브리-페로 간섭계와, 상기 패브리-페로 간섭계에서 간섭된 광선으로 초음파 신호를 검지하는 광검지기 및, 상기 광검지기에서 검지한 초음파 신호에 따라 초음파의 감쇄계수를 계산하는 연산장치를 포함하며,A first laser for irradiating a laser beam to one surface of the object to be measured so as to rapidly increase the surface temperature of one side of the object to be measured and to generate an adiabatic thermal expansion to generate an ultrasonic wave, and to the ultrasonic wave generated by the first laser. A second laser that irradiates a laser beam to the other surface of the measurement object so that the light is reflected by the light, and Fabry-Perot interfering only the light reflected by the other surface of the measurement object among the light reflected by the second laser. An interferometer, an optical detector for detecting an ultrasonic signal with light rays interfered with the Fabry-Perot interferometer, and an arithmetic device for calculating an attenuation coefficient of the ultrasonic wave according to the ultrasonic signal detected by the optical detector, 결정입경과 선형적인 비례관계를 갖는 상기 감쇄계수를 이용하여 측정 대상물의 결정입경을 측정하는 것을 특징으로 하는 비접촉식 결정입경 측정장치.A non-contact grain size measuring apparatus for measuring the grain size of the object to be measured using the attenuation coefficient having a linear proportionality with the grain size. 제1항에 있어서, 상기 제1 레이저는 일정 시간 간격마다 펄스 빔을 발진하는 펄스형 레이저인 것을 특징으로 하는 비접촉식 결정입경 측정장치.The apparatus of claim 1, wherein the first laser is a pulsed laser that oscillates a pulse beam at predetermined time intervals. 제1항에 있어서, 상기 제2 레이저는 측정 대상물의 다른 쪽의 표면에서 반사되는 광선이 간섭되도록 연속적으로 광선을 발진시키는 연속발진 레이저인 것을 특징으로 하는 비접촉식 결정입경 측정장치.The non-contact crystal grain size measurement apparatus according to claim 1, wherein the second laser is a continuous oscillation laser that continuously oscillates a light beam so that the light beam reflected from the other surface of the measurement object is interfered with. 초음파를 이용하여 측정 대상물의 결정입경의 크기를 측정하는 결정입경 측정방법에 있어서,In the crystal grain size measuring method of measuring the size of the crystal grain size of the measurement object using ultrasonic waves, 측정 대상물의 한 쪽의 표면 온도를 급격히 상승시키고 순간적인 단열팽창을 일으켜 초음파가 발생하도록 측정 대상물의 한 쪽의 표면에 레이저 광선을 조사하는 제1 조사단계와, 상기 제1 조사단계에 의해 발생된 초음파에 의해 광선이 반사되도록 측정 대상물의 다른 쪽의 표면에 레이저 광선을 조사하는 제2 조사단계와, 상기 제2 조사단계에 의해 반사된 광선 중 측정 대상물의 다른 쪽의 표면에서 반사된 광선만을 간섭시키는 간섭단계와, 상기 간섭단계에서 간섭된 광선으로 초음파 신호를 검지하는 검지단계 및, 상기 검지단계에서 검지한 초음파 신호에 따라 초음파의 감쇄계수를 계산하는 연산단계를 포함하며,A first irradiation step of irradiating a laser beam to one surface of the object to be measured so as to rapidly increase the surface temperature of one side of the object to be measured and to generate an adiabatic thermal expansion to generate ultrasonic waves; A second irradiation step of irradiating a laser beam to the other surface of the measurement object so that the light beam is reflected by ultrasonic waves; and only the light reflected by the other surface of the measurement object among the light rays reflected by the second irradiation step interferes And a detection step of detecting an ultrasonic signal with light rays interfered in the interference step, and an operation step of calculating an attenuation coefficient of the ultrasonic wave according to the ultrasonic signal detected in the detection step. 결정입경과 선형적인 비례관계를 갖는 상기 감쇄계수를 이용하여 측정 대상물의 결정입경을 측정하는 것을 특징으로 하는 비접촉식 결정입경 측정방법.Non-contact grain size measurement method characterized in that for measuring the crystal grain size of the object to be measured using the attenuation coefficient having a linear proportional to the grain size.
KR10-2000-0080017A 2000-12-22 2000-12-22 Apparatus and method of noncontact measurement of crystal grain size KR100496826B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR10-2000-0080017A KR100496826B1 (en) 2000-12-22 2000-12-22 Apparatus and method of noncontact measurement of crystal grain size

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR10-2000-0080017A KR100496826B1 (en) 2000-12-22 2000-12-22 Apparatus and method of noncontact measurement of crystal grain size

Publications (2)

Publication Number Publication Date
KR20020050833A true KR20020050833A (en) 2002-06-28
KR100496826B1 KR100496826B1 (en) 2005-06-22

Family

ID=27684436

Family Applications (1)

Application Number Title Priority Date Filing Date
KR10-2000-0080017A KR100496826B1 (en) 2000-12-22 2000-12-22 Apparatus and method of noncontact measurement of crystal grain size

Country Status (1)

Country Link
KR (1) KR100496826B1 (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100643351B1 (en) * 2004-10-21 2006-11-10 주식회사 포스코 A System and Method for On-line Measurement of Grain Size using Laser-Ultrasonics
KR100711353B1 (en) * 2006-06-27 2007-04-27 주식회사 포스코 A Stabilizing Apparatus and Method of Laser-Interferometer for Ultrasonic Measurement
KR100723234B1 (en) * 2006-06-27 2007-05-29 주식회사 포스코 Measurement Device and Method of On-line Laser beam for Ultrasonic Detection
KR100951234B1 (en) * 2003-04-18 2010-04-05 주식회사 포스코 An apparatus and method for measuring the recrystallization rate
KR100951233B1 (en) * 2003-04-18 2010-04-05 주식회사 포스코 An apparatus and method for measuring the grain aspect ratio
KR100951232B1 (en) * 2003-04-18 2010-04-05 주식회사 포스코 An apparatus and method for measuring the recrystallization rate and grain aspect ratio
KR101008028B1 (en) * 2004-03-11 2011-01-13 니뽄스틸코포레이션 Method and apparatus for measuring crystal grain size distribution
KR101053347B1 (en) * 2004-03-11 2011-08-01 니뽄스틸코포레이션 Apparatus and method for separating and determining recrystallization rate and grain aspect ratio for separately measuring recrystallization rate and grain aspect ratio for a plate-shaped measurement object
KR101253927B1 (en) * 2011-08-01 2013-04-16 주식회사 포스코 Method and apparatus for measuring quality of steel plate using laser ultrasonic
CN110088565A (en) * 2016-12-22 2019-08-02 株式会社Posco For measuring the device of the crystallite dimension of steel plate
CN113791035A (en) * 2021-11-15 2021-12-14 滨州学院 Laser flaw detection device and laser flaw detection method

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100951234B1 (en) * 2003-04-18 2010-04-05 주식회사 포스코 An apparatus and method for measuring the recrystallization rate
KR100951233B1 (en) * 2003-04-18 2010-04-05 주식회사 포스코 An apparatus and method for measuring the grain aspect ratio
KR100951232B1 (en) * 2003-04-18 2010-04-05 주식회사 포스코 An apparatus and method for measuring the recrystallization rate and grain aspect ratio
KR101008028B1 (en) * 2004-03-11 2011-01-13 니뽄스틸코포레이션 Method and apparatus for measuring crystal grain size distribution
KR101053347B1 (en) * 2004-03-11 2011-08-01 니뽄스틸코포레이션 Apparatus and method for separating and determining recrystallization rate and grain aspect ratio for separately measuring recrystallization rate and grain aspect ratio for a plate-shaped measurement object
KR100643351B1 (en) * 2004-10-21 2006-11-10 주식회사 포스코 A System and Method for On-line Measurement of Grain Size using Laser-Ultrasonics
KR100711353B1 (en) * 2006-06-27 2007-04-27 주식회사 포스코 A Stabilizing Apparatus and Method of Laser-Interferometer for Ultrasonic Measurement
KR100723234B1 (en) * 2006-06-27 2007-05-29 주식회사 포스코 Measurement Device and Method of On-line Laser beam for Ultrasonic Detection
KR101253927B1 (en) * 2011-08-01 2013-04-16 주식회사 포스코 Method and apparatus for measuring quality of steel plate using laser ultrasonic
CN110088565A (en) * 2016-12-22 2019-08-02 株式会社Posco For measuring the device of the crystallite dimension of steel plate
EP3561449A4 (en) * 2016-12-22 2019-11-27 Posco Apparatus for measuring crystal grain size of steel sheet
CN113791035A (en) * 2021-11-15 2021-12-14 滨州学院 Laser flaw detection device and laser flaw detection method

Also Published As

Publication number Publication date
KR100496826B1 (en) 2005-06-22

Similar Documents

Publication Publication Date Title
JP4386709B2 (en) Material nondestructive inspection method and apparatus by laser ultrasonic wave
EP0400770B1 (en) Measuring the strength of a material within a moving web
JP4783263B2 (en) Ultrasonic multi-echo measurement device
KR100496826B1 (en) Apparatus and method of noncontact measurement of crystal grain size
JP2004101189A (en) Apparatus and method for inspecting defect
KR101447392B1 (en) Apparatus and method for measuring metal structure and material
KR101053415B1 (en) Laser Ultrasonic Measuring Device and Measuring Method
Vangi et al. Crack detection with gas-coupled laser acoustic detection technique
JP4412180B2 (en) Laser ultrasonic inspection method and laser ultrasonic inspection device
US7561281B2 (en) System and method for controlling tube thickness
Gulino et al. Non-contact ultrasonic inspection by gas-coupled laser acoustic detection (GCLAD)
Noui et al. A laser beam deflection technique for the quantitative detection of ultrasonic Lamb waves
KR20120113161A (en) Measuring method and measruting apparatus of poisson's ratio
JP4439363B2 (en) Online crystal grain size measuring apparatus and measuring method using laser ultrasonic wave
US7612890B2 (en) System and method for controlling wafer temperature
KR100733539B1 (en) Apparatus and method of laser-ultrasonic measurement for hot object
JPH049641A (en) Method for simultaneously measuring very high speed phenomenon and low frequency heat wave of sample
CA2188705A1 (en) Method and apparatus for exciting bulk acoustic wave
KR20020011662A (en) Method of Detecting Internal Cracks of Steel Products using Laser-Ultrasonic
KR101538908B1 (en) Safety monitoring system of nuclear equipment with intergrating system of laser ultrasonic and shearography
JP2010223635A (en) Device and method for measuring phase transformation rate of material
JP2005300356A (en) Method and apparatus for measuring diameter distribution of crystal grain
KR20050022585A (en) System for defect-detection in plate using a laser excitation typed lamb wave
JP5419677B2 (en) Poisson's ratio measuring method and measuring device
US20230160856A1 (en) Laser-based weld inspection method and system

Legal Events

Date Code Title Description
A201 Request for examination
E902 Notification of reason for refusal
E701 Decision to grant or registration of patent right
GRNT Written decision to grant
FPAY Annual fee payment

Payment date: 20130603

Year of fee payment: 9

FPAY Annual fee payment

Payment date: 20140612

Year of fee payment: 10

FPAY Annual fee payment

Payment date: 20150615

Year of fee payment: 11

FPAY Annual fee payment

Payment date: 20160527

Year of fee payment: 12

LAPS Lapse due to unpaid annual fee