JPS63302359A - Measurement of depth of surface opening defect by using ultrasonic wave - Google Patents

Measurement of depth of surface opening defect by using ultrasonic wave

Info

Publication number
JPS63302359A
JPS63302359A JP62137781A JP13778187A JPS63302359A JP S63302359 A JPS63302359 A JP S63302359A JP 62137781 A JP62137781 A JP 62137781A JP 13778187 A JP13778187 A JP 13778187A JP S63302359 A JPS63302359 A JP S63302359A
Authority
JP
Japan
Prior art keywords
depth
probe
echo
defect
level
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
JP62137781A
Other languages
Japanese (ja)
Inventor
Takeshi Miyajima
宮島 猛
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Construction Machinery Co Ltd
Original Assignee
Hitachi Construction Machinery Co Ltd
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 Hitachi Construction Machinery Co Ltd filed Critical Hitachi Construction Machinery Co Ltd
Priority to JP62137781A priority Critical patent/JPS63302359A/en
Publication of JPS63302359A publication Critical patent/JPS63302359A/en
Pending legal-status Critical Current

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  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Abstract

PURPOSE:To enable the precise measurement of the depth of a surface open defect, by a method wherein scanning is conducted in a liquid with a focal distance of a point focus probe made to be matched with the surface of a substance to be inspected and also made to face the surface and said depth is determined from the amount of variation in the height of an echo from the surface of the substance to be inspected. CONSTITUTION:A point focus probe 1 is made to face a surface 5 at a distance whereat a focus 3 is formed on the surface in coincidence therewith, at a position A, and the probe 1 is moved in the direction of arrows while an ultrasonic wave is emitted toward the surface 5 with the facing distance maintained. During this movement of the probe 1, a reflected wave from the surface 5 is received by the probe 1 and displayed as an echo in CRT or the like. When there is not an open defect 6 in the surface 5, the level of the displayed echo is not varied and the echo is continuous at a substantially unvaried level. The echo level is varied sharply when the probe 1 comes to a position B just above the defect 6. In this way, an echo envelope 8 is obtained when the probe 1 is moved continuously from the position A to a position C. By measuring an amount (h) of fall of the echo level in the envelope 8, accordingly, the depth (d) of the defect 6 having a correlation therewith can be determined.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、超音波を利用して固体に発生した表面開口欠
陥の深さを測定する方法に係わり、特にミクロン単位の
微小の表面開口欠陥深さを精度よく定量的に測定するの
に好適な測定方法に関するものである。
Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method of measuring the depth of surface opening defects generated in a solid using ultrasonic waves, and in particular, the present invention relates to a method for measuring the depth of surface opening defects generated in a solid by using ultrasonic waves. The present invention relates to a measurement method suitable for accurately and quantitatively measuring depth.

〔従来の技術〕[Conventional technology]

溶接部における溶接割れや部材の応力集中部における疲
労き裂等の固体裏面に開口した欠陥の深さを超音波を利
用して測定する方法は各種研究され、その研究結果も報
告されている。例えば(1)端部ピークエコー法による
疲労き裂の深さ測定が「非破壊検査」第31巻第9号昭
59年9月P、690〜P。
Various studies have been conducted on methods using ultrasonic waves to measure the depth of defects opened on the back surface of solids, such as weld cracks in welds and fatigue cracks in stress-concentrated parts of parts, and the results of these studies have also been reported. For example, (1) Fatigue crack depth measurement using the edge peak echo method is used in "Nondestructive Testing", Vol. 31, No. 9, September 1980, P, 690-P.

691に、(2)超音波散乱波を利用したき裂検査法が
「非破壊検査」第29巻第2号昭55年2月P、136
〜P。
691, (2) Crack inspection method using ultrasonic scattered waves was published in "Non-Destructive Testing" Vol. 29, No. 2, February 1980, p. 136.
~P.

137に、(3)鋼板溶接部の溶込み不良欠陥高さの測
定が「非破壊検査」第34巻第2号昭60年2月P、1
12〜P、113に、(4)超音波の伝搬時間による切
欠き深さの測定精度についてか「非破壊検査」第29巻
第2号昭55年2月P、130〜P、131にそれぞれ
報告されている。前記各報告のうち(1)は、点集束形
の縦波斜角探触子を使用し、管の屈曲部内表面の軸方向
に加工された各種深さのスリットについて端部ピークエ
コー法によりビーム路程と深さとの関係を管外周面から
測定し、測定したビーム路程から作成した較正曲線によ
ってき裂深さを求めるものであり、前記報告(2)は、
超音波送波子と受波子を仕切板を介して対象に配置した
探触子を使用し、送波子から水中に置かれた被検体に超
音波を入射したとき、被検体にき裂がない場合とある場
合とで生ずる散乱波の受波子に受信される時間差Δtを
測定し1時間差Δtとき裂深さdとの相関関係を利用し
てき裂深さdを求めるものである。又前記報告(3)は
、二振動子型垂直探触子を平滑に仕上げられた板厚t(
報告では9〜12−)の片面突合せ溶接部上に当接し、
溶接部の溶込み深さdを超音波探傷器の時間軸から直読
して板厚tと比較し溶込み不良欠陥高さh=(t−d)
を測定するものである。前記報告(4)は、超音波の伝
搬時間を高精度で測定できる探傷器を使用し、端部ピー
クエコー法、ショートパルスシアーウニイブ法。
137, (3) Measurement of defect height due to poor penetration of steel plate welds is described in "Nondestructive Testing" Vol. 34, No. 2, February 1986, P. 1
12-P, 113, (4) Regarding the measurement accuracy of notch depth by the propagation time of ultrasonic waves, "Nondestructive Testing" Vol. 29, No. 2, February 1982, P, 130-P, 131, respectively. It has been reported. Among the above reports, (1) uses a point-focusing longitudinal wave angle probe to generate beams using the end peak echo method for slits of various depths machined in the axial direction on the inner surface of the bent part of the tube. The relationship between path length and depth is measured from the outer peripheral surface of the tube, and the crack depth is determined using a calibration curve created from the measured beam path length.
When using a probe with an ultrasonic transmitter and a receiver positioned on the object via a partition plate, and when ultrasonic waves are incident from the transmitter to a test object placed in water, if there are no cracks in the test object. The time difference Δt between the scattered waves received by the wave receiver that occurs in a certain case is measured, and the crack depth d is determined by using the correlation between the 1 time difference Δt and the crack depth d. In addition, the above report (3) describes a dual-element vertical probe with a smooth plate thickness t (
In the report, it abuts on the single-sided butt weld of 9 to 12-),
Directly read the penetration depth d of the welded part from the time axis of the ultrasonic flaw detector and compare it with the plate thickness t to find the penetration defect defect height h = (t-d)
It is used to measure. Report (4) uses a flaw detector that can measure the propagation time of ultrasonic waves with high precision, using the edge peak echo method and the short pulse shear unive method.

表面波法を用いて測定した伝搬時間にもとづいて切欠き
深さを測定するものである。これら各報告のうち(1)
、 (2)および(3)は、いずれも測定方法が実用に
供し得る旨述べられているものの、検出可能な表面開口
欠陥の深さは、該欠陥から反射する散乱波のエコーが送
信波および表面エコーと分離されて表示される範囲に限
定され、報告されているように欠陥深さは0.5m〜数
Iの範囲にとどまり、測定精度も±0.5m程度となっ
ている。また報告(4)は、伝搬時間を高精度で測定で
きる探傷器を使用しているものの、試験した切欠き深さ
の最小値は0.8aである。これはそれ以上の小さい深
さの欠陥に対しては欠陥のない健全部との間に伝搬時間
の差を検出できないからで、検出限界は0.5Illl
I程度と推察される。このように前記各報告の測定方法
では欠陥深さがほぼ0.5+nmより大きい場合でなけ
れば検出し得ないことになる。
The notch depth is measured based on the propagation time measured using the surface wave method. Among these reports (1)
, (2) and (3) both state that the measurement method can be put to practical use. The defect depth is limited to the range that is displayed separately from the surface echo, and as reported, the defect depth remains in the range of 0.5 m to several I, and the measurement accuracy is also about ±0.5 m. Although report (4) uses a flaw detector capable of measuring propagation time with high precision, the minimum value of the notch depth tested is 0.8a. This is because it is not possible to detect the difference in propagation time between a defect at a smaller depth and a healthy part with no defects, so the detection limit is 0.5Illll.
It is estimated to be grade I. As described above, the measurement methods in each of the above reports cannot detect defects unless the defect depth is approximately greater than 0.5+nm.

つぎに、従来の表面開口欠陥深さの測定方法として本出
願人の出願に係わる特願昭60−68379がある。本
出願は垂直探触子を開口欠陥を有する固体表面の該欠陥
上に当接し、開口欠陥の先端に向けて入射した超音波の
欠陥先端から反射する散乱波の伝搬時間を測定して欠陥
深さを求めるものであるが、本出願においても前記報告
(4)と同様に欠陥部と健全部との伝搬時間差の検出に
限界があり、検出限界は欠陥深さが約0.511ffi
lでそれ以下の微小欠陥深さの測定はできない不具合が
ある。
Next, as a conventional method for measuring the depth of surface opening defects, there is Japanese Patent Application No. 60-68379 filed by the present applicant. In this application, a vertical probe is brought into contact with the defect on a solid surface having an aperture defect, and the propagation time of the scattered wave reflected from the defect tip of the ultrasonic wave incident toward the tip of the aperture defect is measured to determine the depth of the defect. However, in this application, as in the above report (4), there is a limit to the detection of the propagation time difference between the defective part and the healthy part, and the detection limit is approximately 0.511ffi when the defect depth is approximately 0.511ffi.
There is a problem that it is not possible to measure the depth of micro defects smaller than 1.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

前記の如く、従来の表面開口欠陥深さの測定方法は、い
ずれも一定の深さより大きい欠陥に対しては実用に供し
得る程度に測定し得るものの、測定可能な欠陥深さがほ
ぼ0.5−〜数Iと大きく、ミクロン単位の微小欠陥深
さを測定することができない問題点があった。
As mentioned above, the conventional surface opening defect depth measurement methods can measure defects larger than a certain depth to a practical extent, but the measurable defect depth is approximately 0.5. - There was a problem in that it was not possible to measure the depth of micro defects in micron units, which were as large as several I.

本発明は前記従来技術の問題点を解消するものであって
、従来測定することのできなかった固体に発生したミク
ロン単位の微小の表面開口欠陥深さを、精度よく定量的
に測定することができる超音波による表面開口欠陥深さ
の測定方法を提供することを目的とする。
The present invention solves the above-mentioned problems of the prior art, and makes it possible to accurately and quantitatively measure the depth of minute surface opening defects in microns that occur in solids, which could not be measured conventionally. The purpose of the present invention is to provide a method for measuring the depth of surface aperture defects using ultrasonic waves.

〔問題点を解決するための手段〕[Means for solving problems]

本発明は、液中に被検体と点焦点探触子とを点焦点探触
子の焦点が被検体の表面に一致する距離で相対させ、そ
の相対距離を保持したまま被検体の表面を走査し、被検
体表面からの反射波のエコー高さを連続的に求め、求め
たエコー高さの変化量を評価指標として表面開口欠陥の
深さを測定することにより、固体の表面に発生している
ミクロン単位の微小の表面開口欠陥深さを、精度よく定
量的に測定することができるようにしたものである。
In the present invention, a subject and a point focus probe are placed in a liquid at a distance such that the focal point of the point focus probe coincides with the surface of the subject, and the surface of the subject is scanned while maintaining that relative distance. Then, the echo height of the reflected wave from the surface of the object is continuously determined, and the depth of the surface aperture defect is measured using the amount of change in the determined echo height as an evaluation index. The depth of microscopic surface opening defects in micron units can be measured quantitatively and accurately.

〔作用〕[Effect]

液中において相対させた被検体の被測定表面と点焦点探
触子は、点焦点探触子の焦点が被測定表面に一致する距
離になっているから、この相対距離を保持したまま被測
定表面を走査すると、超音波は被測定表面で大部分が反
射し残りが被検体内を伝搬する。被測定表面からの反射
波は入射波と同経路で点焦点探触子に受信されエコー表
示されるが、表示される表面エコーレベルは被測定表面
に開口欠陥が無くかつ平滑度が高いほど高低の小さい一
定レベルとなる。走査中点焦点探触子の焦点が表面開口
部に一致すると、超音波は被測定表面から開口内部へ液
中を伝搬し1次第に焦点が拡がりながら欠陥の先端に達
し被検体内に入射するが、欠陥の先端に達した超音波は
該先端部を音源として無指向的に拡がる散乱波を発生し
、その−部が点焦点探触子に受信されエコー表示される
The surface to be measured of the object to be measured and the point focus probe are placed opposite each other in the liquid, and the distance between the point focus probe and the surface to be measured is such that the focal point of the point focus probe matches the surface to be measured. When scanning a surface, most of the ultrasonic waves are reflected from the surface to be measured, and the rest propagates inside the object. The reflected wave from the surface to be measured is received by the point focal point probe along the same path as the incident wave and displayed as an echo, but the displayed surface echo level becomes higher and lower as the surface to be measured has no aperture defects and is smoother. is a small constant level. When the focus of the scanning midpoint focus probe coincides with the surface aperture, the ultrasonic wave propagates through the liquid from the surface to be measured to the inside of the aperture, and the focus gradually expands until it reaches the tip of the defect and enters the object. The ultrasonic wave that reaches the tip of the defect generates a scattered wave that spreads non-directionally using the tip as a sound source, and the negative part of the wave is received by the point focus probe and displayed as an echo.

この場合に表示されるエコーは前記平滑度の高い健全部
の一定レベルのエコーに比べて急激にレベルが低下する
変化を示す。このエコーレベルの低下量は表面開口欠陥
深さと一定の相関関係を有することが実験で確められて
おり、実験により求めた実験式を利用することによりミ
クロン単位の微小の表面開口欠陥深さを精度よく測定す
ることができる。
The echo displayed in this case shows a change in which the level rapidly decreases compared to the constant level echo of the healthy part with a high degree of smoothness. It has been experimentally confirmed that the amount of reduction in the echo level has a certain correlation with the depth of the surface aperture defect, and by using the empirical formula obtained through experiments, the depth of the minute surface aperture defect on the order of microns can be calculated. Can be measured with high precision.

〔実施例〕〔Example〕

本発明の実施例を第1図ないし第5図を参照して説明す
る。第1図は被検体に対する点焦点探触子の走査要領説
明図、第2図は第1図の走査により得られるエコー包絡
線を示す図、第3図は実験に使用した試験体の形状およ
び寸法(単位I)を示す図、第4図は表面開口欠陥深さ
とエコーレベルの変化値との相関関係説明図、第5図は
実際の製品における研摩割れの測定精度の説明図である
Embodiments of the present invention will be described with reference to FIGS. 1 to 5. Figure 1 is an explanatory diagram of the scanning procedure of the point focus probe for the subject, Figure 2 is a diagram showing the echo envelope obtained by the scanning of Figure 1, and Figure 3 is the shape and shape of the specimen used in the experiment. A diagram showing the dimensions (unit I), FIG. 4 is an explanatory diagram of the correlation between the surface opening defect depth and the change value of the echo level, and FIG. 5 is an explanatory diagram of the measurement accuracy of polishing cracks in an actual product.

図において、1は水浸形の点焦点探触子(以下単に探触
子という)、2は水中において探触子1より放射された
ビーム、3はビーム2が集束された焦点、4は被検体、
5は被検体4の平滑に仕上げられた被測定表面(以下単
に表面という)、6は表面5に存在する表面開口欠陥、
7は表面開口欠陥6の先端、8はエコー包絡線を示す。
In the figure, 1 is a water immersion type point-focus probe (hereinafter simply referred to as a probe), 2 is a beam emitted from the probe 1 in water, 3 is a focal point where beam 2 is focused, and 4 is a target. specimen,
5 is a smoothly finished surface to be measured (hereinafter simply referred to as the surface) of the object 4; 6 is a surface opening defect existing on the surface 5;
7 shows the tip of the surface aperture defect 6, and 8 shows the echo envelope.

測定は。As for the measurements.

まず、探触子1を位置(A)において表面5に焦点3が
一致する距離に相対させ、ついで相対距離を保持したま
ま表面5に向けて超音波を発射しながら第1図に示す矢
印方向に探触子1を移動させる。探触子1の移動中、発
射された超音波は表面5で大部分が反射しその残りが被
検体4内に伝搬する。そして表面5からの反射波は入射
波と同経路で探触子1に受信されCRT等にエコー表示
される。表示されるエコーレベルは表面5に表面開口欠
陥6が無い健全部の場合はレベル変化がなくほぼ一定の
レベルで連続する。探触子1が移動して表面開口欠陥6
の直上の位置CB)に達すると、超音波は表面5より表
面開口欠陥6内へ次第に焦点が拡がりながら水中を伝搬
し先端7に達する。
First, the probe 1 is placed opposite the surface 5 at a distance at which the focal point 3 coincides with the position (A), and then, while maintaining the relative distance, an ultrasonic wave is emitted toward the surface 5 in the direction of the arrow shown in Fig. 1. Move probe 1 to . While the probe 1 is moving, most of the emitted ultrasonic waves are reflected by the surface 5 and the remainder propagates into the subject 4. The reflected wave from the surface 5 is received by the probe 1 along the same path as the incident wave and displayed as an echo on a CRT or the like. The displayed echo level does not change in level and continues at a substantially constant level in the case of a healthy area where the surface 5 has no surface opening defect 6. The probe 1 moves and the surface opening defect 6
CB), the ultrasonic wave propagates through the water while its focus gradually expands from the surface 5 into the surface aperture defect 6 and reaches the tip 7.

先端7に達した超音波は先端7を音源として無指向的に
拡がる散乱波を発生させ、その大部分は被検体4内へ入
射し伝搬するが、一部は探触子1に受信されエコー表示
される。この場合に表示されるエコーレベルは急激に低
下し、探触子1が位置(B)に達する以前の健全部の一
定のエコーレベルに比べて急変する。さらに探傷子1を
移動させ位[(B)より位置(C)に移ると1表面5が
第1図に示すような健全部の場合は、位! (A)から
位置(B)までの健全部の場合とほぼ同一レベルの表面
エコーが表示される。前記探触子1を位置(A)から位
置(C)まで連続的に移動させたときのエコーレベルの
変化が第2図に示すエコー包絡線8となる。エコー包絡
線8中のエコーレベルの低下量りは、表面開口欠陥6の
深さdとの間に次式で示す関係を有している。
The ultrasonic waves that reach the tip 7 generate scattered waves that spread non-directionally with the tip 7 as the sound source, most of which enters the object 4 and propagates, but some of it is received by the probe 1 and becomes an echo. Is displayed. In this case, the displayed echo level drops rapidly and changes abruptly compared to the constant echo level of the healthy area before the probe 1 reaches position (B). Further, when the flaw detector 1 is moved from position (B) to position (C), the flaw detector 1 is moved from position (B) to position (C).If surface 5 is a sound part as shown in FIG. Surface echoes at approximately the same level as in the case of the healthy part from position (A) to position (B) are displayed. The change in echo level when the probe 1 is continuously moved from position (A) to position (C) becomes an echo envelope 8 shown in FIG. The reduction in the echo level in the echo envelope 8 has a relationship with the depth d of the surface aperture defect 6 as shown in the following equation.

h=f (d)(λ)(D) 上式中、(λ)は超音波の波長、(D)は超音波のビー
ム径を示す。使用する探触子1が一定ならば(λ)、(
D)とも一定となり、上式は深さくd)のみの関数にな
るから、 h=f(d) となる。したがって本式からエコー包絡線8におけるエ
コーレベルの低下量りを測定することにより、相関関係
を有する表面開口欠陥6の深さdを求めることが可能に
なる、 前記エコーレベルの低下量りと表面開口欠陥深さdとの
相関関係を立証するため、第3図に示す寸法および形状
の試験体を使用して実験を行った。
h=f (d) (λ) (D) In the above formula, (λ) represents the wavelength of the ultrasound, and (D) represents the beam diameter of the ultrasound. If the probe 1 used is constant (λ), (
D) is also constant, and the above equation becomes a function only of the depth d), so h=f(d). Therefore, by measuring the echo level drop in the echo envelope 8 from this formula, it is possible to find the depth d of the surface aperture defect 6, which has a correlation with the echo level drop and the surface aperture defect. In order to prove the correlation with depth d, an experiment was conducted using a test specimen having the dimensions and shape shown in FIG.

第3図(a)は試験体の側面図、第3図(b)は試験体
の平面図で、試験体の材質は高炭素クロム軸受鋼SUJ
 2 (J I 5G4805)を使用し1表面間口欠
陥6を加工する表面5を特に平滑(■1.5〜6S)に
仕上げ、表面5に予め小さいノツチを加工したのち熱処
理条件を変化させて予め加工したノツチ部にき裂を発生
させ、最終的に深さdが7μm〜105μmの12種類
の試験体を作成した。一方、探触子は周波数20MHz
、焦点距離10■、焦点における超音波のビーム径0.
I閣のものを使用した。実験は探触子および試験体を前
記第1図に示す状態に水中において相対させ1表面5上
に焦点を一致させて探触子を走査し、順次試験体を取り
換えて測定した。第4図に示すQ印はその実験結果で、
図の横軸は実験終了後試験体を切断して顕微鏡で測定し
た表面開口欠陥6の深さd(単位μm)の対数値、縦軸
はエコーレベルの変化値(低下量)h(単位dB)の対
数値を示す、各実験値について最小2乗法により回帰式
を求めると、式は h:1o2,6910g d−4,39となり、図中に
直線で示され、実験値の0印のほぼ全数が該直線上にあ
って両者間に良い相関関係の成立することが判る6なお
両者の相関係数γは0.981である。したがってエコ
ーレベルの変化量りを測定し上記回帰式を使用すること
により、表面開口欠陥6の深さdが精度よく定量的に求
められることになる。
Figure 3(a) is a side view of the specimen, and Figure 3(b) is a plan view of the specimen.The material of the specimen is high carbon chromium bearing steel SUJ.
2 (J I 5G4805) to process the 1-surface frontage defect 6. Finish the surface 5 to be particularly smooth (■1.5 to 6S), process a small notch in advance on the surface 5, and then change the heat treatment conditions to A crack was generated in the processed notch portion, and finally 12 types of test specimens having a depth d of 7 μm to 105 μm were created. On the other hand, the frequency of the probe is 20MHz
, focal length 10■, ultrasound beam diameter at focal point 0.
I used one from I-kaku. In the experiment, the probe and the test specimen were placed facing each other in water in the state shown in FIG. 1, and the probe was scanned with the focus on one surface 5, and the test specimen was replaced one after another for measurement. The mark Q shown in Figure 4 is the experimental result,
The horizontal axis of the figure is the logarithmic value of the depth d (unit: μm) of the surface aperture defect 6, which was measured with a microscope by cutting the specimen after the experiment, and the vertical axis is the change value (decrease amount) of the echo level h (unit: dB). ), the regression equation is calculated using the least squares method for each experimental value. It can be seen that all the numbers are on the straight line and a good correlation exists between the two.6The correlation coefficient γ between the two is 0.981. Therefore, by measuring the change in the echo level and using the above regression equation, the depth d of the surface aperture defect 6 can be determined quantitatively and accurately.

つぎに実際の製品の測定例を第5図を参照して説明する
。本例で被検体にした製品は一般の軸。
Next, an example of measuring an actual product will be explained with reference to FIG. The product tested in this example is a general axis.

ギア、スプライン軸等で、深さ6μm〜300μmの研
摩割れの発生している60点を測定対象としてい−る。
The measurement targets were 60 points on gears, spline shafts, etc. where polishing cracks with a depth of 6 μm to 300 μm had occurred.

図の横軸は超音波測定終了後被検体を切断し顕vIl鏡
により測定した実際の研摩割れの深さdR(単位μm)
の対数値、縦軸はエコーレベルの変化量りを測定し前記
回帰式にて求めた本発明の方法による研摩割れ深さの推
定値dυ(単位μm)の対数値である。その推定値を図
中にO印で示す。
The horizontal axis of the figure is the actual depth dR of the abrasive crack (unit: μm), which was measured by cutting the specimen and using a microscope after the ultrasonic measurement was completed.
The vertical axis is the logarithm of the estimated polishing crack depth dυ (in μm) obtained by the method of the present invention by measuring the change in echo level and using the regression equation. The estimated value is indicated by an O mark in the figure.

本測定結果を統計的に処理すると。When this measurement result is statistically processed.

データ数     n=60 誤差の平均値   x =−0,19μm誤差の標準偏
差  σ=6.77μm 誤差率の平均値    0.991% 誤差率の標準偏差   0.087% dRとctuとの相関係数γ=0.962となり、図に
おいても、測定誤差ゼロを示す図中45°の直線dR=
dU上にほとんどの0印が近接する相関を示し、0印の
全数が点線で示す±20%の誤差範囲内にあることを示
している。本測定結果は軸等に発生している深さ6μm
〜300μmのミクロン単位の微小の研摩割れを高精度
にかつ定量的に測定できることを示すものであるが、前
記測定方法が軸等の機械部品に限定されることなく、例
えば電子部品等の他の部品に対してもそのまま適用され
ることは勿論であり、微小欠陥の部品に及ぼす影響の検
討を可能にし、部品の信頼性および安全性の向上を図る
ことができる。
Number of data n = 60 Average value of error x = -0, 19 μm Standard deviation of error σ = 6.77 μm Average value of error rate 0.991% Standard deviation of error rate 0.087% Correlation coefficient between dR and ctu γ=0.962, and in the figure, the 45° straight line dR=
Most of the 0 marks on dU show close correlation, and the total number of 0 marks is within the ±20% error range shown by the dotted line. This measurement result shows a depth of 6 μm that occurs on the shaft, etc.
This shows that it is possible to measure minute abrasive cracks in micron units of ~300 μm with high precision and quantitatively. However, the measurement method is not limited to mechanical parts such as shafts, and can be applied to other mechanical parts such as electronic parts. Of course, it can be applied to parts as is, and it is possible to study the effects of minute defects on parts, thereby improving the reliability and safety of parts.

〔発明の効果〕〔Effect of the invention〕

以上説明したように、本発明は、液中において被検体の
表面に点焦点探触子の焦点距離を一致させて相対させ、
その状態を保持したまま走査して被検体表面のエコー包
絡線を求め、該エコー包絡線の中のエコーレベルの変化
量を評価指標として表面開口欠陥の深さを測定するよう
にしたから、固体の表面に発生しているミクロン単位の
微小の表面開口欠陥深さを、精度よく定量的に測定する
ことができる実用上の顕著な効果を有する。
As explained above, the present invention allows a point-focus probe to face the surface of a subject in a liquid with the same focal length,
The echo envelope of the surface of the object is determined by scanning while maintaining this state, and the depth of the surface aperture defect is measured using the amount of change in the echo level within the echo envelope as an evaluation index. This method has a significant practical effect in that it can accurately and quantitatively measure the depth of minute surface opening defects in micron units that occur on the surface of.

【図面の簡単な説明】[Brief explanation of the drawing]

図面はいずれも本発明に係る測定方法の実施例の説明図
で、第1図は走査要領説明図、第2図は第1図の走査に
より得られるエコー包絡線を示す図、第3図は実験に使
用した試験体を示す図で、第3図(a)は側面図、第3
図(b)は平面図を示し、第4図は表面開口欠陥深さと
エコーレベル変化値との相関関係説明図、第5図は実際
の製品の測定例を示す図である。
The drawings are all explanatory diagrams of the embodiments of the measurement method according to the present invention, and FIG. 1 is an explanatory diagram of the scanning procedure, FIG. 2 is a diagram showing the echo envelope obtained by the scanning of FIG. 1, and FIG. Figures showing the test specimen used in the experiment; Figure 3 (a) is a side view;
FIG. 4 is a diagram illustrating the correlation between the surface aperture defect depth and the echo level change value, and FIG. 5 is a diagram illustrating an example of measurement of an actual product.

Claims (1)

【特許請求の範囲】[Claims] 1、液中に被検体と点焦点探触子とを被検体の表面に点
焦点探触子の焦点が一致する距離で相対させ、その相対
距離を保持したまま被検体の表面を走査し、被検体表面
からの反射波のエコー高さを連続的に求め、求めたエコ
ー高さの変化量を評価指標として表面開口欠陥の深さを
測定する方法。
1. Place the object to be examined and the point focus probe in the liquid at a distance that matches the focus of the point focus probe to the surface of the object, and scan the surface of the object while maintaining that relative distance; A method of measuring the depth of a surface aperture defect by continuously determining the echo height of the reflected wave from the surface of the object and using the amount of change in the determined echo height as an evaluation index.
JP62137781A 1987-06-02 1987-06-02 Measurement of depth of surface opening defect by using ultrasonic wave Pending JPS63302359A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP62137781A JPS63302359A (en) 1987-06-02 1987-06-02 Measurement of depth of surface opening defect by using ultrasonic wave

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP62137781A JPS63302359A (en) 1987-06-02 1987-06-02 Measurement of depth of surface opening defect by using ultrasonic wave

Publications (1)

Publication Number Publication Date
JPS63302359A true JPS63302359A (en) 1988-12-09

Family

ID=15206693

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62137781A Pending JPS63302359A (en) 1987-06-02 1987-06-02 Measurement of depth of surface opening defect by using ultrasonic wave

Country Status (1)

Country Link
JP (1) JPS63302359A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5637799A (en) * 1992-04-15 1997-06-10 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Method and apparatus for evaluating multilayer objects for imperfections

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5255586A (en) * 1975-10-31 1977-05-07 Nippon Steel Corp Method of detecting defects of surface of metal material
JPS61228345A (en) * 1985-04-02 1986-10-11 Hitachi Constr Mach Co Ltd Method for measuring depth of surface aperture flaw of solid by ultrasonic wave

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5255586A (en) * 1975-10-31 1977-05-07 Nippon Steel Corp Method of detecting defects of surface of metal material
JPS61228345A (en) * 1985-04-02 1986-10-11 Hitachi Constr Mach Co Ltd Method for measuring depth of surface aperture flaw of solid by ultrasonic wave

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5637799A (en) * 1992-04-15 1997-06-10 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Method and apparatus for evaluating multilayer objects for imperfections

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