JPH10267902A - Method and device for ultrasonic wave inspecting - Google Patents

Method and device for ultrasonic wave inspecting

Info

Publication number
JPH10267902A
JPH10267902A JP9073052A JP7305297A JPH10267902A JP H10267902 A JPH10267902 A JP H10267902A JP 9073052 A JP9073052 A JP 9073052A JP 7305297 A JP7305297 A JP 7305297A JP H10267902 A JPH10267902 A JP H10267902A
Authority
JP
Japan
Prior art keywords
correlation coefficient
defect
probe
ultrasonic
waveform
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.)
Granted
Application number
JP9073052A
Other languages
Japanese (ja)
Other versions
JP3445914B2 (en
Inventor
Yuji Matsui
祐二 松井
Naoyuki Kono
尚幸 河野
Hiroaki Chiba
弘明 千葉
Akira Fujii
明 藤井
Masahiko Kuroki
雅彦 黒木
Takeshi Iyogi
剛 五代儀
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 Ltd
Tokyo Electric Power Company Holdings Inc
Original Assignee
Tokyo Electric Power Co Inc
Hitachi 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 Tokyo Electric Power Co Inc, Hitachi Ltd filed Critical Tokyo Electric Power Co Inc
Priority to JP07305297A priority Critical patent/JP3445914B2/en
Publication of JPH10267902A publication Critical patent/JPH10267902A/en
Application granted granted Critical
Publication of JP3445914B2 publication Critical patent/JP3445914B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00Investigating 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
    • G01N29/04Analysing solids
    • G01N29/11Analysing solids by measuring attenuation of acoustic waves
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00Indexing codes associated with group G01N29/00
    • G01N2291/04Wave modes and trajectories
    • G01N2291/044Internal reflections (echoes), e.g. on walls or defects
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00Indexing codes associated with group G01N29/00
    • G01N2291/26Scanned objects
    • G01N2291/269Various geometry objects
    • G01N2291/2693Rotor or turbine parts

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Abstract

PROBLEM TO BE SOLVED: To discriminate, with a body on which ultrasonic wave is reflected, whether it is a defect such as crack or non-defect such as rust, when a reflected wave is obtained in the ultrasonic wave inspection of a low-pressure steam turbine wheel. SOLUTION: With a turbine wheel 1 pressed against a prove 9, the entire prove holder is rotated around a turbine shaft 2 to keep a distance and a swing angle from a center axis of the turbine wheel 1 constant, and the prove 9 is scanned under this condition, so that a ultrasonic wave form and prove position are automatically stored in a storage part 1 based on pulse signal 6 emitted from an encoder 5. With a reflected wave obtained, the correlation coefficient 23 of two wave forms recorded at different prove positions is calculated with a mutual correlation processing part 22 and displayed on a display part 24. When the correlation coefficient is larger than a pre-set threshold value, it is discriminated as a defect while when it is smaller discriminated as other than defect.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明は、低圧蒸気タービン
ホイールの翼植込部の欠陥の有無を超音波を用いて検査
する超音波検査方法とその装置に係わるものである。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic inspection method and an ultrasonic inspection method for inspecting a blade implant of a low-pressure steam turbine wheel for defects using ultrasonic waves.

【0002】[0002]

【従来の技術】図6の(A)図,(B)図に、一般的な
低圧蒸気タービンホイールの翼植込部の超音波検査装置
の走査機構部の概要図を示す。
2. Description of the Related Art FIGS. 6A and 6B are schematic views of a scanning mechanism of an ultrasonic inspection apparatus for a blade implantation portion of a general low-pressure steam turbine wheel.

【0003】プラント稼働時には、タービンホイール1
の先端の翼植込部、特にフック部に大きな応力が働くの
で、定期検査期間中にこの部分の健全性を評価する必要
がある。
When the plant is operating, the turbine wheel 1
Since a large stress acts on the wing-implanted portion, particularly the hook portion, at the tip of the blade, it is necessary to evaluate the soundness of this portion during the periodic inspection.

【0004】その一方、プラントの稼働率向上の観点か
ら定期検査の期間短縮の要求が大きくなっていることか
ら、翼植込部の健全性評価にはタービンホイール1から
動翼29を抜き取る必要のない超音波検査が採用される
ことが多い。
On the other hand, there is an increasing demand for shortening the period of the periodic inspection from the viewpoint of improving the operation rate of the plant. Therefore, it is necessary to extract the blade 29 from the turbine wheel 1 to evaluate the soundness of the blade implant. Often no ultrasonography is employed.

【0005】この超音波検査では、一つ、または、二つ
の探触子を探触子保持具3bに取付けてタービンホイー
ル1に押し付け、中心軸からの距離L、および、首振り
角度φを一定に保ったまま探触子保持具3b全体をター
ビンシャフト2の回りに回転させて探触子9を走査する
方法がある。
In this ultrasonic inspection, one or two probes are attached to a probe holder 3b and pressed against the turbine wheel 1, and a distance L from a central axis and a swing angle φ are fixed. There is a method in which the probe 9 is scanned by rotating the entire probe holder 3b around the turbine shaft 2 while keeping the probe 9 at the same position.

【0006】この方法では、予め定めておいた時間ゲー
ト内に反射波がなければ翼植込部は健全であると判断
し、反射波が得られれば翼植込部に割れ等の欠陥が存在
する可能性があると判断する。
In this method, if there is no reflected wave in the gate for a predetermined time, it is determined that the blade implant is sound. If a reflected wave is obtained, there is a defect such as a crack in the blade implant. It is determined that there is a possibility of doing this.

【0007】このような方法の適用例としては、例え
ば、特開平1−161145 号公報,特開平7−244024 号公報
等に記載された例があげられる。
[0007] Examples of the application of such a method include those described in, for example, JP-A-1-161145 and JP-A-7-244024.

【0008】この方法で、タービンホイールの翼植込部
から反射エコーが得られた場合には、一旦動翼を抜取っ
て超音波の反射体が割れ等の欠陥なのか錆や腐食痕等の
欠陥以外のものであるのかを直視等により判断する。
When a reflected echo is obtained from the blade-implanted portion of the turbine wheel by this method, the rotor blade is once extracted to check whether the ultrasonic reflector is defective such as a crack or rust or corrosion marks. It is determined by direct observation or the like whether the defect is other than a defect.

【0009】反射体が欠陥の時には磁粉探傷等により詳
細な検査を実施するが、反射体が錆や腐食痕等の欠陥以
外のものであった場合には1サイクルはそのまま稼働し
て次回定期検査時に詳細な検査を実施する場合が多い。
When the reflector is defective, a detailed inspection is carried out by flaw detection or the like. If the reflector is other than a defect such as rust or a corrosion mark, one cycle is continued and the next periodic inspection is performed. Sometimes a detailed inspection is performed.

【0010】また、タービンホイールの翼植込部ではな
く一般的な溶接部を検査対象とした場合の反射体の種類
を識別する方法としては、例えば特開平6−3332 号公報
に記載された例があげられる。
As a method of identifying the type of reflector when a general welded portion is to be inspected instead of a blade-implanted portion of a turbine wheel, for example, an example described in JP-A-6-3332 is disclosed. Is raised.

【0011】この方法では、反射体に対する超音波の入
射角度を変えながら検査して、入射角度に対応した反射
エコーの強度分布から反射体の偏平率,傾き,対称性等
を求めて、その形状,性状を識別する。
In this method, inspection is performed while changing the incident angle of the ultrasonic wave with respect to the reflector, and the flatness, inclination, symmetry and the like of the reflector are determined from the intensity distribution of the reflected echo corresponding to the incident angle, and the shape thereof is determined. , Identify the properties.

【0012】[0012]

【発明が解決しようとする課題】上述した特開平1−161
145号公報,特開平7−244024号公報等に記載のタービン
ホイールの翼植込部の超音波検査では、被検査部に発生
した錆から反射波が得られた場合に、反射体が欠陥か錆
かを識別するために動翼を抜取る作業が必要となり検査
に時間を要する。
SUMMARY OF THE INVENTION The above-mentioned JP-A-1-161
No. 145, Japanese Patent Application Laid-Open No. 7-244024, and the like, in the ultrasonic inspection of the blade implant portion of the turbine wheel, when a reflected wave is obtained from rust generated on the inspected portion, whether the reflector is defective or not. In order to identify whether it is rust, it is necessary to remove the rotor blades, and it takes time for inspection.

【0013】また、この方法では探触子の首振り角度φ
を一定に保ったまま探触子保持具全体を回転する比較的
簡便な走査法なので、反射体に対する超音波の入射角が
一定となり、入射角度を変化させる必要のある上述した
特開平6−3332 号公報に記載の反射体判別法を適用する
ことはできない。
In this method, the probe swing angle φ
Since the scanning method is relatively simple in which the entire probe holder is rotated while keeping the constant, the incident angle of the ultrasonic wave to the reflector becomes constant, and the incident angle needs to be changed. However, the reflector discrimination method described in Japanese Unexamined Patent Publication (Kokai) No. H10-260 can not be applied.

【0014】言い替えれば、上述した反射体の判別法を
適用するためには、識別したい反射体に対して超音波の
入射角度を変化させられる探触子の走査法を採用する必
要があるが、そのためには新たな探触子走査機構が必要
となり、また、走査に要する時間も長くなる。
In other words, in order to apply the above-described reflector discriminating method, it is necessary to adopt a probe scanning method capable of changing the incident angle of the ultrasonic wave with respect to the reflector to be identified. For that purpose, a new probe scanning mechanism is required, and the time required for scanning becomes long.

【0015】本発明は、このような課題に鑑み、タービ
ンホイールの翼植込部の超音波検査において反射波が得
られた場合に、動翼を抜取ることなく、かつ、比較的簡
便な探触子走査法で、超音波反射体が欠陥か欠陥以外の
ものかを識別可能な超音波検査方法および装置を提供す
ることを目的とする。
The present invention has been made in view of the above problems, and when a reflected wave is obtained in an ultrasonic inspection of a blade implant portion of a turbine wheel, a relatively simple search is performed without removing a moving blade. It is an object of the present invention to provide an ultrasonic inspection method and apparatus capable of distinguishing whether an ultrasonic reflector is a defect or something other than a defect by a probe scanning method.

【0016】[0016]

【課題を解決するための手段】本発明の目的を達成する
ための手段は、低圧蒸気タービンホイールの翼植込部に
探触子を用いて超音波を入射し、予め定めておいた時間
ゲート内で反射波を受信しなければ翼植込部は健全であ
ると判断し、前記時間ゲート内で反射波を受信すれば前
記翼植込部に欠陥が存在する可能性があると判断する超
音波検査法において、前記反射波を受信する探触子位置
で収録した前記時間ゲート内の波形と、前記探触子位置
とは異なる他の探触子位置で収録した前記時間ゲート内
の波形とを、相互相関処理して相関係数を算出し、前記
相関係数が予め定めたしきい値より大きい場合には前記
翼植込部に前記欠陥があると判断し、前記相関係数が前
記しきい値より小さい場合には前記欠陥以外のものであ
ると判断することを特徴とする超音検査方法、及び低圧
蒸気タービンホイールの翼植込部に超音波を送受信する
探触子と、前記探触子を走査する手段と、予め定めてお
いた時間ゲート内で前記探触子で受信した受信波形を収
録する手段と、を備える超音波検査装置において、互い
に異なる操作位置で収録した複数の前記受信波形同士を
相互相関処理して相関係数を算出する手段と、前記相関
係数を算出する手段で算出した相関係数を表示する手段
と、を備えることを特徴とする超音波検査装置である。
Means for attaining the object of the present invention is to provide a low-pressure steam turbine wheel, in which ultrasonic waves are incident on a blade implant portion using a probe and a predetermined time gate is set. If the reflected wave is not received within the wing, the wing implant is determined to be sound, and if the reflected wave is received within the time gate, it is determined that the wing implant may have a defect. In the sonography method, a waveform in the time gate recorded at a probe position receiving the reflected wave, and a waveform in the time gate recorded at another probe position different from the probe position. The cross-correlation processing is performed to calculate a correlation coefficient, and when the correlation coefficient is larger than a predetermined threshold value, it is determined that the wing implant has the defect, and the correlation coefficient is If it is smaller than the threshold value, it is judged that the defect is not the above A supersonic inspection method, a probe that transmits and receives ultrasonic waves to and from a blade implant of a low-pressure steam turbine wheel, a unit that scans the probe, and a probe that scans the probe within a predetermined time gate. Means for recording a received waveform received by the stylus, and an ultrasonic inspection apparatus comprising: a means for calculating a correlation coefficient by performing a cross-correlation process between the plurality of received waveforms recorded at different operation positions from each other; Means for displaying the correlation coefficient calculated by the means for calculating the correlation coefficient.

【0017】[0017]

【発明の実施の形態】本発明の実施例では、予め定めて
おいた時間ゲート内の最大振幅がしきい値を超える反射
波が得られる探触子位置で収録したゲート内の波形と、
この位置の近傍だが異なる探触子位置で同様に収録した
波形とを、相互相関処理して求めた相関係数を算出し、
予め定めた相関係数のしきい値との大小関係をみて探触
子での受信波形が欠陥によるものか錆等の欠陥以外によ
るものかを判定している。
DESCRIPTION OF THE PREFERRED EMBODIMENTS In an embodiment of the present invention, a waveform in a gate recorded at a probe position at which a reflected wave whose maximum amplitude in a gate exceeds a threshold for a predetermined time is obtained;
A correlation coefficient calculated by performing a cross-correlation process on a waveform near the position but similarly recorded at a different probe position is calculated,
The magnitude of the correlation coefficient with a predetermined threshold value is determined to determine whether the waveform received by the probe is due to a defect or a defect other than a defect such as rust.

【0018】その判定に至るまでの原理をまず説明する
と次の通りである。
The principle up to the determination is first described as follows.

【0019】図2に、割れ等の欠陥からの反射波が得ら
れる場合と、錆や腐食痕等の欠陥以外のものからの反射
波が得られる場合の状況を模式的に示す。
FIG. 2 schematically shows a case where a reflected wave from a defect such as a crack is obtained and a case where a reflected wave from a material other than a defect such as rust or a corrosion mark is obtained.

【0020】割れ27では超音波反射体が一箇所で位置
が明確なため、図3(A)に示すような比較的単純な波
形となる。また、探触子位置をA1からA2へ走査して
も、路程が変化するだけで、受信波形に大きな変化はな
い。
Since the position of the ultrasonic reflector is clear at one location in the crack 27, the waveform has a relatively simple waveform as shown in FIG. Further, even when the probe position is scanned from A1 to A2, only the path changes, and there is no significant change in the received waveform.

【0021】ゲートの時間幅をTw,位置A1で収録し
た波形をX(t),位置A2で収録した波形をY(t)とし
たときに、X(t)とY(t)を時間差τずらしたときの相
関値R(τ)は、
When the time width of the gate is Tw, the waveform recorded at the position A1 is X (t), and the waveform recorded at the position A2 is Y (t), the time difference τ is defined as X (t) and Y (t). The correlation value R (τ) when shifted is

【0022】[0022]

【数1】 (Equation 1)

【0023】で表わされ、τを−TwからTwまで変化
させたときの相関値R(τ)の最大値を相関係数と呼ぶ。
相関係数は2波形の関連の深さを示す指標であり、反射
体が欠陥の場合には図3(A)に示すように大きな値を
とる。
The maximum value of the correlation value R (τ) when τ is changed from −Tw to Tw is called a correlation coefficient.
The correlation coefficient is an index indicating the depth of the relationship between the two waveforms, and takes a large value as shown in FIG. 3A when the reflector is defective.

【0024】これに対し、錆28では一つの明確な超音
波反射体はなく、複数の小さな反射体がタービンホイー
ル頭頂部表面で複雑に分布しているために、図3(B)
に示すように複数の反射波が重畳した波形となる。ま
た、探触子位置をB1からB2へ走査すると、複数の反
射体からの反射波の強度比が変化するので受信波形が異
なってくる。位置B1で収録した波形と位置B2で収録
した波形から算出した相関係数は、図3(B)に示すよ
うに小さな値をとる。
On the other hand, in the rust 28, there is no clear ultrasonic reflector, and a plurality of small reflectors are distributed in a complicated manner on the top surface of the turbine wheel.
As shown in FIG. 7, a waveform in which a plurality of reflected waves are superimposed is obtained. Further, when the probe position is scanned from B1 to B2, the received waveform differs because the intensity ratio of the reflected waves from the plurality of reflectors changes. The correlation coefficient calculated from the waveform recorded at the position B1 and the waveform recorded at the position B2 takes a small value as shown in FIG.

【0025】したがって、2箇所の探触子位置で収録し
た超音波波形同士を相互相関処理をして相関係数を算出
し、相関係数が大きい時には欠陥、小さい時には欠陥以
外のものと識別することができる。
Therefore, the ultrasonic waveforms recorded at the two probe positions are subjected to cross-correlation processing to calculate a correlation coefficient, and if the correlation coefficient is large, it is identified as a defect, and if it is small, it is identified as a defect other than a defect. be able to.

【0026】以下、本発明の実施例を図面を参照してよ
り具体的に説明する。
Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings.

【0027】図1に、本発明による低圧蒸気タービンホ
イール翼植込部の超音波検査装置の構成の一例を示す。
FIG. 1 shows an example of the configuration of an ultrasonic inspection apparatus for a low-pressure steam turbine wheel blade implant according to the present invention.

【0028】タービンホイール1に探触子保持具3aを
用いて探触子9を押し付けた状態で、車輪4a,4bに
よりタービンシャフト2の外周上を走行する。
While the probe 9 is pressed against the turbine wheel 1 using the probe holder 3a, the wheel 9 travels on the outer periphery of the turbine shaft 2 by the wheels 4a and 4b.

【0029】探傷器12から探触子9にパルス電圧11
aを印加してタービンホイール1の翼植込部に超音波1
0を入射し、探触子9で受信した反射波の超音波信号1
1bを探傷器12で増幅する。
The pulse voltage 11 from the flaw detector 12 to the probe 9
a to apply ultrasonic waves 1 to the blade implant portion of the turbine wheel 1.
0, the ultrasonic signal 1 of the reflected wave received by the probe 9
1b is amplified by the flaw detector 12.

【0030】探触子保持具3b全体をタービンシャフト
2の回りに回転させることにより、タービンホイール1
の中心軸からの距離、および、首振り角度を一定に保っ
た状態で探触子9を走査できるので、探触子保持具3b
を一旦取付けてしまえば、比較的簡便な操作でタービン
ホイール1の翼植込部の全周を検査することができる。
By rotating the entire probe holder 3b around the turbine shaft 2, the turbine wheel 1
The probe 9 can be scanned in a state where the distance from the central axis and the swing angle are kept constant, so that the probe holder 3b can be scanned.
Once is installed, the entire circumference of the blade implant portion of the turbine wheel 1 can be inspected by a relatively simple operation.

【0031】探触子保持具3bにはエンコーダ5が設置
してあり、探触子9が一定距離移動するたびにパルス信
号6を発信する。
An encoder 5 is provided on the probe holder 3b, and emits a pulse signal 6 every time the probe 9 moves a predetermined distance.

【0032】A/D変換部15は、パルス信号6を受信
した直後の探傷器12のトリガ信号13に同期した超音
波信号14をA/D変換する。
The A / D converter 15 A / D converts the ultrasonic signal 14 synchronized with the trigger signal 13 of the flaw detector 12 immediately after receiving the pulse signal 6.

【0033】トリガ信号13を受信してから変換を開始
するまでの時間Ts、および、変換の時間幅Twは、予
め設定しておく。
The time Ts from the reception of the trigger signal 13 to the start of the conversion and the time width Tw of the conversion are set in advance.

【0034】このときの、Tsから(Ts+Tw)まで
が時間ゲートに相当する。位置読取部7では、超音波検
査の開始時に位置信号をリセットして0としておき、以
後、パルス信号6を受信するたびに位置信号の数を1ず
つ加算していき、位置信号の数とパルス信号6の積算値
が等しくなるようにする。
At this time, a period from Ts to (Ts + Tw) corresponds to a time gate. The position reading unit 7 resets the position signal to 0 at the start of the ultrasonic examination, and thereafter, increments the number of position signals by one each time the pulse signal 6 is received. The integrated value of the signal 6 is made equal.

【0035】位置読取部7で読み取った位置信号8、お
よび、A/D変換部15で変換したデジタル信号16
は、自動的に記憶部17に転送して記憶させる。
The position signal 8 read by the position reading unit 7 and the digital signal 16 converted by the A / D conversion unit 15
Is automatically transferred to the storage unit 17 and stored.

【0036】このような構成とすることにより、探触子
保持具3bの回転操作に追随して、超音波波形と探触子
位置を自動的に収録することが可能となる。
With this configuration, the ultrasonic waveform and the probe position can be automatically recorded following the rotation operation of the probe holder 3b.

【0037】まず、このような波形自動収録式の超音波
検査装置を用いて、検査しながら反射体が欠陥か欠陥以
外のものかを識別する例について説明する。
First, an example will be described in which the reflector is used to determine whether the reflector is a defect or something other than a defect while performing an inspection using such a waveform automatic recording type ultrasonic inspection apparatus.

【0038】反射波の有無判定部18では、時間幅Tw
のデジタル信号16の最大振幅を抽出して予め設定して
おいたしきい値と比較し、最大振幅がしきい値より大き
ければ反射波があると判定し、最大振幅がしきい値より
小さければ反射波がないと判定する。
In the reflected wave presence / absence determination unit 18, the time width Tw
The maximum amplitude of the digital signal 16 is extracted and compared with a preset threshold. If the maximum amplitude is larger than the threshold, it is determined that there is a reflected wave. It is determined that there is no wave.

【0039】判定結果19は、記憶部17に転送され
て、位置信号8,デジタル信号16と関連づけて記憶す
る。
The judgment result 19 is transferred to the storage unit 17 and stored in association with the position signal 8 and the digital signal 16.

【0040】反射波があると連続して2回判定した場合
には、その2回の反射波形を相互相関処理する。
If it is determined that there is a reflected wave twice consecutively, the two reflected waveforms are cross-correlated.

【0041】例えば、探触子位置Pで収録した超音波の
デジタル信号20と探触子位置P+1で収録した超音波
のデジタル信号21の両波形に反射波があると判定する
と、この2波形を相互相関処理部22で演算して相関係
数23を算出する。
For example, if it is determined that there are reflected waves in both waveforms of the digital ultrasonic signal 20 recorded at the probe position P and the ultrasonic digital signal 21 recorded at the probe position P + 1, these two waveforms are determined. The cross-correlation processing unit 22 calculates the correlation coefficient 23.

【0042】相関係数23は、記憶部17に転送され
て、位置信号8,デジタル信号16,判定結果19と関
連づけて記憶する。
The correlation coefficient 23 is transferred to the storage unit 17 and stored in association with the position signal 8, the digital signal 16, and the determination result 19.

【0043】さらに、探触子位置P+2で収録した超音
波波形に反射波があると判定すれば、探触子位置P+1
で収録した超音波波形と探触子位置P+2で収録した超
音波波形を相互相関処理して相関係数を算出し、記憶部
17に記憶する。
Further, if it is determined that there is a reflected wave in the ultrasonic waveform recorded at the probe position P + 2, the probe position P + 1
The cross-correlation processing is performed on the ultrasonic waveform recorded at the step S1 and the ultrasonic waveform recorded at the probe position P + 2 to calculate a correlation coefficient, which is stored in the storage unit 17.

【0044】図4にこのような信号処理手法を用いて、
人工的に欠陥と錆を発生させたテストロータを検査した
結果を、表示部24に表示した例を示す。
Referring to FIG. 4, using such a signal processing method,
An example in which the result of inspecting a test rotor in which defects and rust are artificially generated is displayed on the display unit 24 is shown.

【0045】画面下段には収録した超音波波形の最大振
幅とそのしきい値が表示し、最大振幅がしきい値より大
きい探触子位置41〜46、および、55〜60では反
射波があるので、相互相関処理をしている。
The lower part of the screen displays the maximum amplitude of the recorded ultrasonic waveform and its threshold, and there are reflected waves at probe positions 41 to 46 and 55 to 60 where the maximum amplitude is larger than the threshold. Therefore, cross-correlation processing is performed.

【0046】画面上段に、算出した相関係数とそのしき
い値を表示しており、探触子位置41〜46では相関係
数はしきい値より大きく、探触子位置55〜60では相
関係数はしきい値より小さくなっている。
The calculated correlation coefficient and its threshold value are displayed in the upper part of the screen. The correlation coefficient is larger than the threshold value at the probe positions 41 to 46, and the correlation coefficient is larger at the probe positions 55 to 60. The relation number is smaller than the threshold.

【0047】検査員は、この表示を見ることにより、探
触子位置41〜46の反射波の反射体は欠陥で、探触子
位置55〜60の反射波の反射体は欠陥以外のものであ
ると判断することができる。
By looking at this display, the inspector finds that the reflected wave reflector at the probe positions 41 to 46 is a defect and the reflected wave reflector at the probe positions 55 to 60 is a defect other than the defect. It can be determined that there is.

【0048】なお、図4の例では探触子位置が35〜6
5の範囲でしか表示していないが、探触子の走査にした
がって表示範囲が自動更新されるようになっている。
In the example of FIG. 4, the probe position is 35 to 6
Although the display is performed only in the range of 5, the display range is automatically updated according to the scanning of the probe.

【0049】また、この実施例では反射波があると判断
した場合だけ相互相関処理を行ったが、収録した全波形
に対して相互相関処理を行って相関係数を算出し、図4
と同様に表示しても、反射体が欠陥か欠陥以外のものか
を検査員が判断可能であることはいうまでもない。
In this embodiment, the cross-correlation processing is performed only when it is determined that there is a reflected wave. However, the correlation coefficient is calculated by performing the cross-correlation processing on all the recorded waveforms.
It goes without saying that the inspector can determine whether the reflector is a defect or something other than a defect even if the display is made in the same manner as in the above.

【0050】次に、タービンホイール翼植込部の全周か
らの超音波を一旦収録してから、反射体が欠陥か錆かを
識別する例について図5を用いて説明する。
Next, an example will be described with reference to FIG. 5 in which ultrasonic waves from the entire circumference of the turbine wheel blade implant portion are once recorded, and then the reflector is identified as a defect or rust.

【0051】探触子保持具3bをタービンホイール1に
対して一回転操作すると、記憶部17に全周分の位置信
号8,デジタル信号16,反射波の有無の判定結果19
が収録される。
When the probe holder 3b is operated by one rotation with respect to the turbine wheel 1, the storage unit 17 stores the position signal 8, the digital signal 16, and the determination result 19 of the presence or absence of the reflected wave for the entire circumference.
Is recorded.

【0052】ここで、連続して反射波があると判定した
探触子位置をグループ化し、グループ内で最大振幅が最
大となる探触子位置で収録した波形を基準波形とし、基
準波形とグループ内の他の探触子位置で収録した波形と
を相互相関処理する。
Here, the probe positions where it is determined that there is a reflected wave continuously are grouped, and the waveform recorded at the probe position having the maximum amplitude in the group is defined as a reference waveform. Cross-correlation processing is performed with the waveforms recorded at the other probe positions inside.

【0053】例えば、図5に示す例の場合には、探触子
位置41〜46、および、55〜60を、それぞれグル
ープと考える。
For example, in the case of the example shown in FIG. 5, the probe positions 41 to 46 and 55 to 60 are considered as groups.

【0054】位置41〜46のグループで、最大振幅が
最大なのは位置43で収録した波形なので、これを基準
波形する。
In the group of the positions 41 to 46, the waveform having the largest maximum amplitude is the waveform recorded at the position 43, which is used as a reference waveform.

【0055】以下、基準波形と位置41,42,44,
45,46で収録した波形との相関係数を相互相関処理
部22で順次算出し、表示部24で表示する。
Hereinafter, reference waveforms and positions 41, 42, 44,
Correlation coefficients with the waveforms recorded at 45 and 46 are sequentially calculated by the cross-correlation processing unit 22 and displayed on the display unit 24.

【0056】反射体識別部26は、算出した相関係数を
基に反射体が欠陥か欠陥以外のものかを自動識別し、識
別結果25を表示部24で表示する。
The reflector identifying unit 26 automatically identifies whether the reflector is a defect or something other than a defect based on the calculated correlation coefficient, and displays the identification result 25 on the display unit 24.

【0057】この識別結果としては、例えば、以下の式
に示す、確信度などを用いる。
As the identification result, for example, a certainty factor shown in the following equation is used.

【0058】(欠陥の確信度)=(基準波形との相関係
数がしきい値より大きい波形数)/(グループの波形数
−1) (欠陥以外の確信度)=(基準波形との相関係数がしき
い値より小さい波形数)/(グループの波形数−1) 図5の表示例では、最大振幅,相関係数,確信度の全て
を表示しているので、検査員は、反射体が欠陥か欠陥以
外のものかを判断をすること、および、その判断の確実
性を知ることが可能となる。
(Degree of Degree of Defect) = (Number of waveforms whose correlation coefficient with reference waveform is larger than threshold) / (Number of waveforms of group-1) (Degree of certainty other than defect) = (Phase of reference waveform) In the display example of FIG. 5, all of the maximum amplitude, the correlation coefficient, and the certainty factor are displayed. It is possible to determine whether the body is a defect or something other than a defect, and to know the certainty of the determination.

【0059】なお、識別結果としては、相関係数の平均
としきい値を比較する方法など、上記した確信度以外の
方法を用いてもよい。
As a discrimination result, a method other than the certainty factor described above, such as a method of comparing the average of the correlation coefficient with a threshold value, may be used.

【0060】また、基準波形の選定法としては、グルー
プの中央位置で収録した波形とするなど、上記した最大
振幅が最大となる選定法を用いてもよい。
As a method for selecting a reference waveform, a method for maximizing the above-described maximum amplitude, such as a waveform recorded at the center position of a group, may be used.

【0061】なお、反射波があると判定した探触子位置
が連続しない場合、相互相関処理をするべき波形を選定
できないので、本方法では反射体を識別できない。
When the probe position determined to have a reflected wave is not continuous, it is not possible to select a waveform to be subjected to cross-correlation processing, and therefore, it is not possible to identify a reflector by this method.

【0062】このような場合には、エンコーダ5のパル
ス信号を発信する移動距離を短いものに変更し、収録す
る波形の数が多くなる設定にして再度波形収録を行う。
In such a case, the moving distance for transmitting the pulse signal of the encoder 5 is changed to a shorter one, and the waveform recording is performed again with the setting to increase the number of waveforms to be recorded.

【0063】反射波があると判定する波形が連続して収
録できれば、上記のいずれかの方法により反射体が欠陥
か欠陥以外のものかを識別できる。
If the waveform for determining that there is a reflected wave can be recorded continuously, it is possible to identify whether the reflector is a defect or something other than a defect by any of the above methods.

【0064】[0064]

【発明の効果】本発明によれば、比較的簡便な探触子走
査法による低圧蒸気タービンホイールの翼植込部の超音
波検査において反射エコーが得られた場合に、動翼を抜
取ることなく超音波反射体が欠陥であるか欠陥以外のも
のであるかを識別することができるので、検査の工程数
削減と期間短縮が可能となる。
According to the present invention, when a reflected echo is obtained in an ultrasonic inspection of a blade implantation portion of a low-pressure steam turbine wheel by a relatively simple probe scanning method, a rotor blade is extracted. It is possible to identify whether the ultrasonic reflector is a defect or a defect other than a defect, so that the number of inspection steps and the period can be reduced.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明の実施例による超音波検査装置の構成を
示したブロック図である。
FIG. 1 is a block diagram showing a configuration of an ultrasonic inspection apparatus according to an embodiment of the present invention.

【図2】本発明の実施例による超音波検査装置における
割れと錆からの超音波反射の状況を示す概念図である。
FIG. 2 is a conceptual diagram showing the state of ultrasonic reflection from cracks and rust in the ultrasonic inspection apparatus according to the embodiment of the present invention.

【図3】本発明の実施例による超音波検査装置の収録波
形と相関処理結果の波形とを示した波形グラフ図であっ
て、(A)図は反射体が割れによる欠陥の場合を、(B)
図は反射体が錆の場合をそれぞれ示した図である。
FIG. 3 is a waveform graph showing a recorded waveform of an ultrasonic inspection apparatus according to an embodiment of the present invention and a waveform of a correlation processing result. FIG. 3A shows a case where a reflector is defective due to cracking. B)
The figure shows the case where the reflector is rust.

【図4】本発明の実施例による超音波検査装置の超音波
検査結果の表示例を示す図である。
FIG. 4 is a view showing a display example of an ultrasonic inspection result of the ultrasonic inspection apparatus according to the embodiment of the present invention.

【図5】本発明の実施例による超音波検査装置の超音波
検査結果の他の表示例を示す図である。
FIG. 5 is a diagram showing another display example of the ultrasonic inspection result of the ultrasonic inspection apparatus according to the embodiment of the present invention.

【図6】従来技術による超音波検査装置の検査状態にお
ける機構部分の図であって、(A)図は立面図を、
(B)図は(A)図の側面図を表している。
FIG. 6 is a view of a mechanism portion in an inspection state of the ultrasonic inspection apparatus according to the related art, wherein FIG.
(B) shows a side view of (A).

【符号の説明】[Explanation of symbols]

1…タービンホイール、2…タービンシャフト、3a,
3b…探触子保持具、4a,4b…車輪、5…エンコー
ダ、6…パルス信号、7…位置読取部、8…位置信号、
9…探触子、10…超音波、11a…パルス電圧、11
b…超音波信号、12…探傷器、13…トリガ信号、1
4…超音波信号、15…A/D変換部、16…デジタル
信号、17…記憶部、18…反射波の有無判定部、19
…判定結果、20〜21…デジタル信号、22…相互相
関処理部、23…相関係数、24…表示部、25…識別
結果、26…反射体識別部、27…欠陥、28…錆、2
9…動翼。
DESCRIPTION OF SYMBOLS 1 ... Turbine wheel, 2 ... Turbine shaft, 3a,
3b: probe holder, 4a, 4b: wheel, 5: encoder, 6: pulse signal, 7: position reading unit, 8: position signal,
9: probe, 10: ultrasonic wave, 11a: pulse voltage, 11
b: ultrasonic signal, 12: flaw detector, 13: trigger signal, 1
4 ... Ultrasonic signal, 15 ... A / D converter, 16 ... Digital signal, 17 ... Storage unit, 18 ... Reflected wave presence / absence determination unit, 19
... Judgment results, 20 to 21 digital signal, 22 cross-correlation processing unit, 23 correlation coefficient, 24 display unit, 25 identification result, 26 reflector identification unit, 27 defect, 28 rust, 2
9 ... Blade.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 千葉 弘明 茨城県日立市幸町三丁目1番1号 株式会 社日立製作所日立工場内 (72)発明者 藤井 明 神奈川県横浜市鶴見区江ヶ崎町4番1号 東京電力株式会社エネルギー環境研究所内 (72)発明者 黒木 雅彦 神奈川県横浜市鶴見区江ヶ崎町4番1号 東京電力株式会社エネルギー環境研究所内 (72)発明者 五代儀 剛 神奈川県横浜市鶴見区江ヶ崎町4番1号 東京電力株式会社エネルギー環境研究所内 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroaki Chiba 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Inventor Akira Fujii Egasaki, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture 4-1, Tokyo Electric Power Company Energy Energy Research Laboratory (72) Inventor Masahiko Kuroki 4-1 Egasaki-cho, Tsurumi-ku, Yokohama, Kanagawa Prefecture, Tokyo Energy Energy Research Laboratory Tokyo Electric Power Company (72) Inventor Tsuyoshi Godai Kanagawa 4-1 Egasaki-cho, Tsurumi-ku, Yokohama-shi

Claims (3)

【特許請求の範囲】[Claims] 【請求項1】低圧蒸気タービンホイールの翼植込部に探
触子を用いて超音波を入射し、予め定めておいた時間ゲ
ート内で反射波を受信しなければ翼植込部は健全である
と判断し、前記時間ゲート内で反射波を受信すれば前記
翼植込部に欠陥が存在する可能性があると判断する超音
波検査法において、 前記反射波を受信する探触子位置で収録した前記時間ゲ
ート内の波形と、前記探触子位置とは異なる他の探触子
位置で収録した前記時間ゲート内の波形とを、相互相関
処理して相関係数を算出し、前記相関係数が予め定めた
しきい値より大きい場合には前記翼植込部に前記欠陥が
あると判断し、前記相関係数が前記しきい値より小さい
場合には前記欠陥以外のものであると判断することを特
徴とする超音検査方法。
An ultrasonic wave is incident on a blade implantation portion of a low-pressure steam turbine wheel using a probe, and if a reflected wave is not received within a predetermined time gate, the blade implantation portion is sound. It is determined that there is a possibility that there is a possibility that a defect exists in the wing implanted portion if a reflected wave is received in the time gate.In the ultrasonic inspection method, at a probe position where the reflected wave is received. The waveform in the time gate recorded and the waveform in the time gate recorded at another probe position different from the probe position are cross-correlated to calculate a correlation coefficient, and the correlation coefficient is calculated. If the number of relations is larger than a predetermined threshold, it is determined that the wing implanted part has the defect, and if the correlation coefficient is smaller than the threshold, it is determined that the defect is other than the defect. A supersonic inspection method characterized by making a judgment.
【請求項2】低圧蒸気タービンホイールの翼植込部に超
音波を送受信する探触子と、 前記探触子を走査する手段と、 予め定めておいた時間ゲート内で前記探触子で受信した
受信波形を収録する手段と、を備える超音波検査装置に
おいて、 互いに異なる操作位置で収録した複数の前記受信波形同
士を相互相関処理して相関係数を算出する手段と、 前記相関係数を算出する手段で算出した相関係数を表示
する手段と、を備えることを特徴とする超音波検査装
置。
2. A probe for transmitting and receiving ultrasonic waves to and from a blade implant of a low-pressure steam turbine wheel, means for scanning the probe, and reception by the probe within a predetermined time gate. Means for recording a received waveform obtained by performing a cross-correlation process on a plurality of the received waveforms recorded at different operation positions to calculate a correlation coefficient. Means for displaying the correlation coefficient calculated by the calculating means.
【請求項3】請求項2において、予め定めた相関係数の
しきい値と前記相関係数を算出する手段で算出した相関
係数と予め定めた相関係数のしきい値との大小関係を判
定する自動識別手段と、 前記自動識別手段の判定結果を表示する手段と、 とを備えることを特徴とする超音波検査装置。
3. A magnitude relationship between a predetermined threshold value of a correlation coefficient, a correlation coefficient calculated by a means for calculating the correlation coefficient, and a predetermined threshold value of a correlation coefficient. An ultrasonic inspection apparatus, comprising: automatic identification means for determining the condition; and means for displaying the determination result of the automatic identification means.
JP07305297A 1997-03-26 1997-03-26 Ultrasonic inspection method and apparatus Expired - Lifetime JP3445914B2 (en)

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JPH10267902A true JPH10267902A (en) 1998-10-09
JP3445914B2 JP3445914B2 (en) 2003-09-16

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003294716A (en) * 2002-03-29 2003-10-15 Hitachi Ltd Inspection method of turbine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003294716A (en) * 2002-03-29 2003-10-15 Hitachi Ltd Inspection method of turbine

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Publication number Publication date
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