JPH0146027B2 - - Google Patents
Info
- Publication number
- JPH0146027B2 JPH0146027B2 JP57233944A JP23394482A JPH0146027B2 JP H0146027 B2 JPH0146027 B2 JP H0146027B2 JP 57233944 A JP57233944 A JP 57233944A JP 23394482 A JP23394482 A JP 23394482A JP H0146027 B2 JPH0146027 B2 JP H0146027B2
- Authority
- JP
- Japan
- Prior art keywords
- scanning
- probe
- steel piece
- square steel
- flaw detection
- 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.)
- Expired
Links
- 238000001514 detection method Methods 0.000 claims description 51
- 229910000831 Steel Inorganic materials 0.000 claims description 47
- 239000010959 steel Substances 0.000 claims description 47
- 239000000523 sample Substances 0.000 claims description 46
- 239000002344 surface layer Substances 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 8
- 230000007547 defect Effects 0.000 description 45
- 238000010586 diagram Methods 0.000 description 18
- 238000000034 method Methods 0.000 description 16
- 238000007920 subcutaneous administration Methods 0.000 description 6
- 238000002592 echocardiography Methods 0.000 description 2
- 230000010365 information processing Effects 0.000 description 2
- 238000002604 ultrasonography Methods 0.000 description 2
- 235000014676 Phragmites communis Nutrition 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
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
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/26—Arrangements for orientation or scanning by relative movement of the head and the sensor
- G01N29/262—Arrangements for orientation or scanning by relative movement of the head and the sensor by electronic orientation or focusing, e.g. with phased arrays
-
- 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
-
- 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
-
- 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
- G01N2291/023—Solids
- G01N2291/0234—Metals, e.g. steel
-
- 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
- G01N2291/04—Wave modes and trajectories
- G01N2291/042—Wave modes
- G01N2291/0421—Longitudinal waves
-
- 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
- G01N2291/10—Number of transducers
- G01N2291/106—Number of transducers one or more transducer arrays
Landscapes
- Physics & Mathematics (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)
- Acoustics & Sound (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
Description
(産業上の利用分野)
本発明は、角鋼片の表面皮下を含む内部欠陥を
有効に検出するための超音波探傷法に関する。
(従来の技術)
従来角鋼片の内部欠陥の探傷には、超音波垂直
探傷法が応用されているが、この場合には第11
図に示すように、探触子1から角鋼片2に発信さ
れた超音波Sがその入射面で反射エコーS1、底面
で反射エコーB1を生じ、表面近傍は不感帯とな
る欠点がある。
そこで、前記欠点を解消するため、角鋼片の外
周面から面の法線に対して側方へ傾斜させて超音
波を該角鋼片へ発信すると共に受信して超音波入
射面と隣接する該角鋼片の皮下近傍の内部欠陥を
検出する。いわゆる斜角探傷法が知られている
(例えば、特開昭56−126761号公報参照)。
この斜角探傷法を用いる場合には、第12図に
示すように、超音波Sの入射面からの反射エコー
S1は相当残存しているが、角鋼片2の側面からの
反射エコーS2は下方に進向するため、側面では反
射エコーによる不感帯を生じない。そこで斜角探
傷法を用い、その入射面に隣接する側面を探傷域
とすることによつて、角鋼片2の表面から内部ま
で不感帯なしに探傷が可能となる。
一方、角鋼片の全面全長に亘つてオンラインで
探傷するためには、超音波ビームを高速で走査さ
せなければならない。この場合、走査方式を大別
すると機械的走査と電子走査とに分けられるが、
高速走査性、指向性、欠陥位置推定精度等の諸点
で、電子の走査方式によるのが遥かに有利であ
る。また電子走査による場合でも、さらに電子リ
ニア走査と電子セクター走査とがある(例えば、
特開昭52−84884号公報、特開昭53−140879号公
報参照)。
前記電子走査に用いられる探触子は電子走査ア
レイ型探触子と呼ばれ、第13図に示すように、
多数の振動子素子3を基体4平面上に一列に配列
させ、その表面にコーテイング5を施して構成さ
れる。該探触子からの超音波ビームの制御は、各
素子3の送受波のタイミングを遅延時間制御回路
で調整することにより行われる。例えば第14図
に示すように遅延時間を設定しない場合には、
その超音波ビームSは単一の大口径振動子からの
波面と等価な波面を形成するが、この遅延時間を
適宜に設定すると、第14図aのようにビーム
Sを傾けたり、第14図bのように絞つたりあ
るいは第14図cのようにビームSを絞つて傾
ける波面を自在に形成することができる。
このような探触子を電子走査し、超音波ビーム
を入射面上に平行移動させるかもしくは振る電子
リニアもしくはセクター走査の特徴を要約する
と、次の通りである。
(i) 高速走査性
機械的走査に比べて高速走査が容易である。
(ii) 鋭い指向性
電子走査型探触子は多数の振動子エレメント
を同時に動作させるため、全体としては大口径
の振動子と同じであり鋭い指向性を有してい
る。
(iii) 電子収束
電子走査型探触子は、前述の通り、送受波信
号に所定の遅延時間を与えることにより、凹面
振動子やレンズ付き振動子と同様にビームを細
く絞り分解能を上げた探傷を可能にする。そし
てこの焦点距離は任意に設定できるため、材中
の探傷領域にビームを収束させることによつて
微小な欠陥の検出精度を向上させることができ
ると同時に、欠陥位置推定精度も向上する。参
考として、角鋼片探傷時の超音波ビーム径と
φ2の横穴に対するS/Nの関係を第15図に
示す。
(iv) 探触子を固定した状態で超音波ビームを走査
させることができるので、一つの探触子で広い
探傷域が得られる。
次に、このような特徴を有する電子走査アレイ
型探触子を用いて電子リニア走査する場合と、電
子セクター走査する場合を対比して説明する。
まず、電子リニア走査する場合では、探触子1
を所定の状態でセツトして、第18図a,b,c
に示すように、超音波ビームSを入射面上に平行
移動させ乍ら、その隣接する側面の表面層の側を
探傷して行くものである。このさい必要な走査回
路例を挙げれば、第17図に示す通りである。す
なわち、例えば総エレメント数64個のリニアアレ
イ探触子を16個のエレメントを1セツトとして、
探触子1と送受信器6とを先に述べた遅延回路7
に加えてリードリレー回路8を介して接続し、切
換スイツチで順次送受信のエレメントをずらし、
超音波ビームを走査するのである。
一方電子セクター走査する場合では、やはり探
触子1を所定の状態にセツトして、第16図a,
b,cに示すように、超音波ビームSを入射面に
対して振り乍ら、その隣接する側面下半分の表面
層の側を探傷して行くものである。このさいの必
要な走査回路例を挙げれば、第19図に示す通り
である。すなわち、例えば総分割エレメント数32
個の探触子1と送受信器6とを遅延回路7を介し
て1対1に対応させて接続し、その遅延回路7に
よる遅延時間設定を順次変えることによつて、超
音波ビームの傾き角を変化させ、ビームを振る走
査をするのである。
(発明が解決しようとする課題)
前記電子リニア走査の場合、次の欠点があつ
た。
(i) 送受信エレメントを順次ずらすため、エレメ
ント総数が多くなり全体として振動子径が大き
くなる。
(ii) 切り換えに多数のリレーが必要であり、この
リレーの寿命が短い。
(iii) 送受信エレメントを順次ずらすため、送受信
器(T/R Unit)とエレメントが1対1の
対応にならないため、感度バラツキの調整が困
難である。
(iv) 超音波ビームの入射点の移動量が大きいた
め、角鋼片の表面凹凸の影響を受け屈折角が変
化し、欠陥位置推定精度が劣化する。
一方、電子セクター走査の場合では、第16図
に示すように、超音波ビームSを振ることによつ
て、角鋼片2の入射面における入射点がずれると
いう問題点がある。
即ち、前記電子リニア走査、電子セクター走査
にいずれの場合も、角鋼片の入射面における入射
点がずれるため、入射面上に存在する凹凸によつ
て検出精度にバラツキが生じると言う問題があつ
た。
即ち、入射面が全面にわたつて均一かつ平坦面
であれば、入射点が順次移動しても検出精度に影
響を与えないが、角鋼片にあつては中央部と両側
部とでは面の状態や凹凸度(平坦度)が異なるた
め、入射点の位置によつて精度を補正しなけれ
ば、全面にわたつて同じ精度で探傷できないと言
う問題があつた。
そこで、本発明は、入射面の状態如何にかかわ
らず高精度の検出ができる角鋼片の探傷法を提供
することを目的とする。
(課題を解決するための手段)
前記目的を達成するため、本発明は、次の手段
を講じた。即ち、本発明の特徴とする処は、電子
走査アレイ型探触子を用いる縦波斜角探傷法であ
つて、前記探触子を、角鋼片軸方向に垂直な面内
でその材表面から所定の距離で、かつ又材表面に
対して所定の角度でセツトし、前記探触子を電子
セクター走査に電子リニア走査を組み合わせて走
査することにより、前記材表面での入射点を略一
定にして、角鋼片の内部および入射面に隣接する
側面の表面層を探傷する点にある。
(作 用)
本発明はこの縦波斜角探傷法により角鋼片の内
部および入射面に隣接する側面を探傷することを
基本原理とするものである。
そこで、超音波に縦波を用いることおよび縦波
斜角探傷による探傷領域について説明する。
先ず縦波を用いる理由は次の通りである。すな
わち、斜角探傷法に横波を用いた場合では、第2
図からも判るように、屈折角34゜以下では往復通
過率が小さいこと、屈折角30゜〜40゜の範囲で探傷
する場合では入射面の形状、入射角の設定のわず
かな誤差によつて往復通過率が激変すること、ま
た往復通過率の変動の少ない屈折角50゜〜65゜の範
囲を使用すると、幾何学的に探傷領域である入射
面に隣接する側面の下方が探傷できないことの欠
点がある。一方縦波を用いた場合では、屈折角の
変化による往復通過率の変動が比較的少なく連続
的であることの利点があり、かかる点から縦波を
導入する。
次に、縦波斜角探傷法を用いてセクター走査す
る場合の有効な探傷領域について説明すると、屈
折角が大きくなると横波の影響を受けること(第
2図参照)、また側面反射エコーの受信により側
表面近傍のS/Nが低下することから、屈折角は
最大50゜程度に限定される。すなわち、探傷領域
は第3図に示す如く、角鋼片2の側面下半分の表
面層の側に限定される。
次に、探触子セツト方法について説明する。
電子走査アレイ型探触子においては、グレーテ
イングロープの発生を防ぐために必要とされる振
動子エレメント間隔dは、超音波ビームSの最大
傾斜角を±θ0とすれば、
d<λ/1+1sinθ01
λ:超音波伝播媒質中の波長
で表わされる。よつて超音波ビームSの傾斜角を
大きくするためには、λ一定ではそのエレメント
間隔dを小さくしなければならない(第4図a,
bにエレメント幅と最大ビーム傾斜角θ0との関係
を示す)。すなわち、エレメント幅は小さくする
必要がある。
探触子のセツト法は、この特性を利用して次の
二通りの方法を提案することができる。
(i) 一つは、角鋼片軸方向に垂直な面内でその材
表面から所定の距離に位置して、探触子をその
入射面に対して水平にセツトする方法である。
但し、この場合には探触子の各エレメント幅を
小さくし、分割数を多くする。このセツト法に
よる場合の特徴は、最大ビーム傾斜角が大きい
ので、入射面に隣接する両側面の探傷が可能と
なることである。
(ii) もう一つは、やはり角鋼片軸方向に垂直な面
内でその材表面から所定の距離に位置して、探
触子をその入射面に対してセクター走査の振り
の中心となる入射角分だけ傾斜させてセツトす
る方法である。このセツト法による場合の特徴
は、ビーム傾斜角の絶対値が小さくなるので、
最大遅延時間が小さくて済むことである。ま
た、ビーム傾斜角の絶対値が小さくなるので、
探触子のエレメント分割数が大きくてもよい。
次に、電子セクター走査に電子リニア走査を組
み合わせて走査することにつき説明する。
電子セクター走査のみの場合、第1図に示す
ように、超音波ビームSを振ることによつて、角
鋼片2に入射面における入射点がずれるので、本
発明では、セクター走査にリニア走査を組み合わ
せて行ない、第1図a,b,cに示すよう
に、各ビーム傾斜角に応じて送受信エレメントを
シフトさせ、これによつて入射点のずれを最小限
におさえ、電子セクター走査以上に入射面の影響
を受け難く、従つて欠陥位置推定精度の向上が図
れる。
(実施例)
以下、本発明の実施例を説明する。
第5図と第6図は角鋼片2に対する探触子1の
配置状態を示す。まず第5図の例の場合では、角
鋼片2の各面に対して平行に1個づつ探触子1が
配置される。すなわち、1個の探触子1で図示の
如く入射面に隣接する角鋼片2の両側面下半分を
探傷するのであり、4個の探触子1で角鋼片2の
全表面層を探傷するのである。一方第6図の例の
場合では、角鋼片2の各面に対して所定の角度を
もつて2個づつ探触子1が配置される。すなわ
ち、この場合には1個の探触子1で図示の如く入
射面に隣接する角鋼片2の片側面下半分を探傷
し、合計8個の探触子1を用いて角鋼片全長面層
を探傷するのである。いずれの配置による場合で
も、オンラインで角鋼片全表面層に亘る高速探傷
が可能とされる。
そして、前記探触子1を電子セクター走査に電
子リニア走査を組み合わせて走査することによ
り、材表面での入射点を第1図a,b,c
に示す如く、略一定にして探傷する。
入射点を略一定にすることにより、角鋼片1の
表面凹凸の影響を受けず、屈折角が一定となり、
欠陥位置推定精度が全面にわたつて均一化され
る。
次に角鋼片の表面欠陥を弁別するための処理に
ついて説明する。上記に述べた本発明の電子リニ
ア走査による斜角探傷法によれば、目的とする角
鋼片の全表面に亘りその表面皮下疵を含む内部欠
陥を高速で精度よく検出することができる。とこ
ろで、角鋼片の表面層を探傷すると、表面皮下欠
陥のみならず表面疵も同時に検出され、その探傷
結果には表面欠陥探傷により検出した情報も含ま
れている。しかるに、表面疵については鋼片加工
工程のチツピングやグラインダによる加工によつ
て除去することができ、製品の二次加工時に問題
となるものではなく、それ故表面疵を含まない内
部欠陥(もちろん表面皮下欠陥を含む)のみを検
出することが必要である。
しかして内部欠陥の検出には、既述の角鋼片内
部からの超音波斜角探傷の結果より表面欠陥探傷
の結果を差し引けばよい。下記表に各表面欠陥探
傷法をの検出能と共に示す。
(Industrial Application Field) The present invention relates to an ultrasonic flaw detection method for effectively detecting internal defects including subcutaneous defects on the surface of a square steel piece. (Prior art) Conventionally, an ultrasonic vertical flaw detection method has been applied to detect internal defects in square steel pieces.
As shown in the figure, the ultrasonic wave S emitted from the probe 1 to the square steel piece 2 produces a reflected echo S 1 on the incident surface and a reflected echo B 1 on the bottom surface, which has the drawback of creating a dead zone near the surface. Therefore, in order to eliminate the above-mentioned drawbacks, ultrasonic waves are transmitted from the outer circumferential surface of the square steel piece to the square steel piece by tilting it laterally with respect to the normal line of the surface, and the ultrasonic waves are received by the square steel piece adjacent to the ultrasonic incident surface. Detect internal defects near the subcutaneous part of the piece. A so-called oblique flaw detection method is known (see, for example, Japanese Patent Laid-Open No. 126761/1983). When using this angle flaw detection method, as shown in Fig. 12, the reflected echo from the incident surface of the ultrasonic wave S is
Although a considerable amount of S 1 remains, since the reflected echo S 2 from the side surface of the square steel piece 2 travels downward, a dead zone due to the reflected echo does not occur on the side surface. Therefore, by using the angle angle flaw detection method and setting the side surface adjacent to the entrance plane as the flaw detection area, it becomes possible to detect flaws from the surface to the inside of the square steel piece 2 without a dead zone. On the other hand, in order to perform online flaw detection over the entire length of a square steel piece, it is necessary to scan the ultrasonic beam at high speed. In this case, scanning methods can be roughly divided into mechanical scanning and electronic scanning.
The electronic scanning method is far more advantageous in terms of high-speed scanning, directivity, defect position estimation accuracy, etc. Even in the case of electronic scanning, there are further electronic linear scanning and electronic sector scanning (for example,
(See JP-A-52-84884 and JP-A-53-140879). The probe used for the electronic scanning is called an electronic scanning array type probe, and as shown in FIG.
It is constructed by arranging a large number of transducer elements 3 in a line on the plane of a base 4, and applying a coating 5 to the surface thereof. The ultrasonic beam from the probe is controlled by adjusting the timing of wave transmission and reception of each element 3 using a delay time control circuit. For example, if the delay time is not set as shown in Figure 14,
The ultrasonic beam S forms a wavefront equivalent to the wavefront from a single large-diameter transducer, but if this delay time is set appropriately, the beam S can be tilted as shown in Figure 14a, or It is possible to freely form a wavefront that narrows the beam S as shown in b, or narrows and tilts the beam S as shown in FIG. 14c. The characteristics of electronic linear or sector scanning, in which such a probe is electronically scanned and the ultrasonic beam is translated or swung onto the incident surface, are summarized as follows. (i) High-speed scanning ability High-speed scanning is easier than mechanical scanning. (ii) Sharp directivity Since an electronic scanning probe operates many transducer elements simultaneously, it has sharp directivity, which is the same as a large-diameter transducer as a whole. (iii) Electron focusing As mentioned above, electronic scanning probes can be used for flaw detection by narrowing the beam and increasing resolution, similar to concave vibrators and lensed vibrators, by giving a predetermined delay time to the transmitted and received signals. enable. Since this focal length can be set arbitrarily, by converging the beam on the flaw detection area in the material, the accuracy of detecting minute defects can be improved, and at the same time, the accuracy of estimating the defect position is also improved. For reference, Fig. 15 shows the relationship between the ultrasonic beam diameter during flaw detection of a square steel piece and the S/N for a φ2 horizontal hole. (iv) Since the ultrasonic beam can be scanned with the probe fixed, a wide flaw detection area can be obtained with one probe. Next, a case where electronic linear scanning is performed using an electronically scanned array type probe having such characteristics and a case where electronic sector scanning is performed will be compared and explained. First, in the case of electronic linear scanning, the probe 1
18a, b, c.
As shown in FIG. 2, while the ultrasonic beam S is moved parallel to the incident surface, the surface layer side of the adjacent side surface is detected for flaws. An example of the scanning circuit required in this case is as shown in FIG. That is, for example, if a linear array probe with a total number of elements of 64 is set as one set of 16 elements,
The probe 1 and the transceiver 6 are connected to the delay circuit 7 described above.
In addition, connect via reed relay circuit 8, shift the transmitting and receiving elements sequentially with a changeover switch,
It scans the ultrasound beam. On the other hand, in the case of electronic sector scanning, the probe 1 is also set in a predetermined state and the probes shown in FIG.
As shown in b and c, the ultrasonic beam S is swung toward the incident surface and the surface layer side of the lower half of the adjacent side surface is detected for flaws. An example of the scanning circuit required in this case is shown in FIG. That is, for example, the total number of divided elements is 32
By connecting the probes 1 and the transmitter/receiver 6 in a one-to-one correspondence via a delay circuit 7, and sequentially changing the delay time setting of the delay circuit 7, the inclination angle of the ultrasonic beam can be adjusted. This is done by changing the beam and scanning by swinging the beam. (Problems to be Solved by the Invention) The electronic linear scanning has the following drawbacks. (i) Since the transmitting and receiving elements are sequentially shifted, the total number of elements increases and the overall transducer diameter increases. (ii) A large number of relays are required for switching, and the lifespan of these relays is short. (iii) Since the transmitter/receiver elements are sequentially shifted, there is no one-to-one correspondence between the transmitter/receiver (T/R unit) and the element, making it difficult to adjust sensitivity variations. (iv) Since the amount of movement of the incident point of the ultrasonic beam is large, the refraction angle changes due to the influence of the surface unevenness of the square steel piece, and the defect position estimation accuracy deteriorates. On the other hand, in the case of electronic sector scanning, as shown in FIG. 16, there is a problem in that by swinging the ultrasonic beam S, the point of incidence on the incident surface of the square steel piece 2 is shifted. That is, in both electronic linear scanning and electronic sector scanning, there is a problem in that the point of incidence on the incident surface of the rectangular steel piece shifts, resulting in variations in detection accuracy due to unevenness on the incident surface. . In other words, if the incident surface is uniform and flat over the entire surface, detection accuracy will not be affected even if the incident point moves sequentially, but in the case of a square piece of steel, the condition of the surface may vary between the center and both sides. There was a problem in that it was not possible to detect flaws with the same accuracy over the entire surface unless the accuracy was corrected depending on the position of the incident point because of the difference in the degree of unevenness and unevenness (flatness). SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a flaw detection method for a rectangular steel piece that can perform highly accurate detection regardless of the state of the entrance surface. (Means for Solving the Problems) In order to achieve the above object, the present invention takes the following measures. That is, the present invention is characterized by a longitudinal wave angle flaw detection method using an electronically scanned array type probe, in which the probe is moved from the surface of a square steel piece in a plane perpendicular to the axial direction of the piece. By setting the probe at a predetermined distance and at a predetermined angle with respect to the material surface, and scanning the probe using a combination of electronic sector scanning and electronic linear scanning, the incident point on the material surface is made approximately constant. The purpose of this method is to detect flaws in the interior of the square steel piece and the surface layer on the side surface adjacent to the entrance surface. (Function) The basic principle of the present invention is to detect the inside of a square steel piece and the side surface adjacent to the incident surface by this longitudinal wave oblique angle flaw detection method. Therefore, the use of longitudinal waves for ultrasonic waves and the flaw detection area by longitudinal wave oblique angle flaw detection will be explained. First, the reason for using longitudinal waves is as follows. In other words, when a transverse wave is used in the oblique flaw detection method, the second
As can be seen from the figure, the reciprocating pass rate is small when the refraction angle is 34° or less, and when detecting flaws in the refraction angle range of 30° to 40°, due to slight errors in the shape of the entrance surface and the setting of the incidence angle. It is possible that the round-trip passage rate changes dramatically, and that if a refraction angle in the range of 50° to 65° is used, where the round-trip passage rate does not fluctuate much, the lower part of the side surface adjacent to the entrance surface, which is the geometrical flaw detection area, cannot be detected. There are drawbacks. On the other hand, when longitudinal waves are used, there is an advantage that fluctuations in the round-trip pass rate due to changes in the refraction angle are relatively small and continuous, and longitudinal waves are introduced from this point. Next, we will explain the effective detection area when sector scanning is performed using the longitudinal wave oblique angle flaw detection method.As the refraction angle increases, it will be affected by transverse waves (see Figure 2), and the reception of side reflection echoes will Since the S/N ratio near the side surface decreases, the refraction angle is limited to a maximum of about 50°. That is, the flaw detection area is limited to the surface layer side of the lower half of the side surface of the square steel piece 2, as shown in FIG. Next, a method for setting the probe will be explained. In an electronically scanned array type probe, the transducer element spacing d required to prevent the generation of grating ropes is d<λ/1+1sinθ, where the maximum inclination angle of the ultrasound beam S is ± θ0 . 0 1 λ: Expressed by the wavelength in the ultrasonic propagation medium. Therefore, in order to increase the inclination angle of the ultrasonic beam S, the element spacing d must be decreased when λ is constant (Fig. 4a,
(b shows the relationship between element width and maximum beam inclination angle θ 0 ). That is, the element width needs to be made small. The following two methods for setting the probe can be proposed using this characteristic. (i) One method is to position the probe at a predetermined distance from the surface of the square steel piece in a plane perpendicular to the axial direction of the piece, and set the probe horizontally to the plane of incidence.
However, in this case, the width of each element of the probe is made smaller and the number of divisions is increased. A feature of this set method is that since the maximum beam inclination angle is large, it is possible to detect flaws on both sides adjacent to the entrance surface. (ii) The other method is to place the probe at a predetermined distance from the surface of the square steel piece in a plane perpendicular to the axis of the piece, and place the probe at the center of incidence for sector scanning with respect to the incidence plane. This is a method of setting it by tilting it by an angle. The feature of this setting method is that the absolute value of the beam inclination angle becomes small, so
The maximum delay time can be small. Also, since the absolute value of the beam inclination angle becomes smaller,
The number of element divisions of the probe may be large. Next, scanning by combining electronic linear scanning with electronic sector scanning will be explained. In the case of only electronic sector scanning, as shown in FIG. 1, by swinging the ultrasonic beam S, the point of incidence on the incident surface of the square steel piece 2 is shifted. Therefore, in the present invention, linear scanning is combined with sector scanning. As shown in FIG. Therefore, the defect position estimation accuracy can be improved. (Example) Hereinafter, an example of the present invention will be described. 5 and 6 show the arrangement of the probe 1 with respect to the square steel piece 2. FIG. First, in the case of the example shown in FIG. 5, one probe 1 is arranged parallel to each surface of the square steel piece 2. That is, one probe 1 detects flaws in the lower half of both sides of the rectangular steel piece 2 adjacent to the entrance plane as shown in the figure, and four probes 1 detect the entire surface layer of the rectangular steel piece 2. It is. On the other hand, in the case of the example shown in FIG. 6, two probes 1 are arranged at a predetermined angle to each surface of the square steel piece 2. That is, in this case, one probe 1 is used to detect the lower half of one side of the square steel piece 2 adjacent to the entrance plane as shown in the figure, and a total of eight probes 1 are used to detect the entire length surface layer of the square steel piece 2. It is used to detect flaws. In either arrangement, high-speed flaw detection can be performed online over the entire surface layer of a square steel piece. Then, by scanning the probe 1 with a combination of electronic sector scanning and electronic linear scanning, the incident point on the material surface is determined as shown in Fig. 1 a, b, and c.
As shown in the figure, the flaws are detected at a constant temperature. By keeping the incident point approximately constant, the angle of refraction becomes constant without being affected by the surface unevenness of the square steel piece 1.
Defect position estimation accuracy is made uniform over the entire surface. Next, a process for identifying surface defects in square steel pieces will be explained. According to the above-described angle flaw detection method using electronic linear scanning of the present invention, internal defects including surface subcutaneous flaws can be detected with high precision over the entire surface of a target square steel piece at high speed. By the way, when the surface layer of a square steel piece is flaw-detected, not only surface subcutaneous defects but also surface flaws are detected at the same time, and the flaw detection results also include information detected by surface flaw detection. However, surface defects can be removed by chipping or grinding in the billet processing process, and do not pose a problem during secondary processing of the product. Therefore, internal defects that do not include surface defects (of course, surface defects It is necessary to detect only subcutaneous defects (including subcutaneous defects). Therefore, in order to detect internal defects, it is sufficient to subtract the results of surface defect detection from the results of ultrasonic angle inspection from the inside of the square steel piece described above. The table below shows each surface defect detection method along with its detection ability.
【表】
表面欠陥の検出能がその表面欠陥探傷法により
異なることから判るように、どの表面欠陥探傷法
と組み合わせるかによつて内部欠陥の検出特性が
決定される。
表面欠陥弁別のための情報処理法として、基本
的には第7図に示すように、情報1から情報2を
差し引けばよいが、超音波斜角探傷は欠陥位置推
定精度を低下させる要因を多く含んでいるため、
情報1は表面欠陥探傷からの欠陥位置情報(情報
2)に比べて信頼性が低く、欠陥位置推定誤差範
囲が大きい。そのため第8図に示すような表面欠
陥に対して、欠陥位置情報として図中の印の位置
に欠陥があるものとして情報1、情報2を得た場
合、これらの情報をそのまま情報処理すると、別
個の欠陥と判断され、情報1は内部欠陥情報とし
て残される。すなわち、内部欠陥を有しないのに
内部欠陥材とされる。
これを防ぐために情報2に一定の領域をもた
せ、その領域に入る情報1はキヤンセルすること
によつて表面欠陥を内部欠陥と誤検出することを
防止する。ここで情報2にもたせる領域をどの程
度にするかは情報1の精度の良否によるが、この
精度は超音波ビーム径(細い程よい即ち絞つた状
態)、入射面形状(入射面に凹凸があると見かけ
上屈折角が変化するので入射点の変動が少なくか
つ入射面が平坦である程よい)に起因するところ
大であり、この面で電子リニア走査に比較すると
電子セクター走査並びに(電子セクター+リニア
走査)は有利である。
そこで電子セクター+リニア走査によつて斜角
探傷する場合では、より一層欠陥位置推定精度を
向上するために次の二つの方法を併用することが
できる。
一つは入射面の凹凸の影響が最も少ないと考え
られる面中央部から超音波を入射することであ
る。つまりこうすることにより、第9図a,bに
示す如く、角鋼片2の表面に凹凸があつても、面
中央部ではほぼ平坦と近似することができる。
もう一つの方法は、第10図に示すような入射
面の傾斜による見かけ上の屈折角の変化(S0→
S)を補正するために、コーナー部からのエコー
を検出し、その最大値を示す入射角を求めること
である。そしてその値より入射面の傾斜を算出
し、所望の探傷域にビームが入るように入射角を
補正すればよい。尚、角鋼片または検出部のいず
れか一方を移動させた状態で探傷してもよいこと
は言うまでもない。
(発明の効果)
本発明によれば、電子セクター走査にリニア走
査を組合わせて走査することにより、角鋼片表面
の入射点を略一定にしているので、入射面上に存
在する凹凸の影響を受けず、欠陥位置を精度よく
検出することができるものである。[Table] As can be seen from the fact that the detection ability of surface defects varies depending on the surface defect detection method, the detection characteristics of internal defects are determined depending on which surface defect detection method is used in combination. As an information processing method for surface defect discrimination, basically information 2 can be subtracted from information 1 as shown in Fig. 7, but ultrasonic angle flaw detection can eliminate the factors that reduce defect position estimation accuracy. Because it contains a lot of
Information 1 is less reliable than the defect position information (information 2) from surface defect detection and has a larger defect position estimation error range. Therefore, when information 1 and information 2 are obtained for a surface defect as shown in Figure 8, assuming that the defect is located at the mark in the figure as defect position information, if these pieces of information are processed as they are, they will be separated into is determined to be a defect, and information 1 is left as internal defect information. In other words, it is considered an internally defective material even though it does not have any internal defects. To prevent this, information 2 is provided with a certain area, and information 1 that falls within that area is canceled, thereby preventing surface defects from being erroneously detected as internal defects. The extent of the area to be given to information 2 here depends on the accuracy of information 1, but this accuracy depends on the ultrasonic beam diameter (the thinner the better, that is, the narrowed state), the shape of the incident surface (if there are irregularities on the incident surface) This is largely due to the fact that the apparent angle of refraction changes, so the smaller the variation in the incident point and the flatter the plane of incidence, the better. ) is advantageous. Therefore, when performing oblique flaw detection using electronic sector + linear scanning, the following two methods can be used in combination to further improve defect position estimation accuracy. One method is to make the ultrasonic waves enter from the center of the surface, where the influence of irregularities on the incident surface is considered to be the least. In other words, by doing this, even if the surface of the square steel piece 2 has irregularities as shown in FIGS. 9a and 9b, it can be approximated to be substantially flat at the center of the surface. Another method is to change the apparent angle of refraction (S 0 →
In order to correct S), the echoes from the corners are detected and the angle of incidence indicating the maximum value thereof is determined. Then, the slope of the incident surface is calculated from that value, and the incident angle is corrected so that the beam enters the desired flaw detection area. It goes without saying that flaw detection may be performed with either the square steel piece or the detection part moved. (Effects of the Invention) According to the present invention, by scanning a combination of electronic sector scanning and linear scanning, the incident point on the surface of the square steel piece is kept approximately constant, so the influence of unevenness existing on the incident surface is eliminated. Therefore, the defect position can be detected with high accuracy.
第1図,a,b,cは電子セクター走
査と電子セクター+リニア走査を比較して示す図
である。第2図は入射角による縦波、横波の往復
通過率の変化を示す図である。第3図は本発明に
係る縦波斜角探傷による探傷領域を示す図であ
る。第4図は電子走査型探触子のもつ振動子エレ
メント幅と最大ビーム傾斜角との関係を示す図で
ある。第5図と第6図は角鋼片に対する探触子の
配置状態を示す図である。第7図は表面欠陥弁別
のための情報処理と検出パターンを示す図であ
る。第8図は超音波斜角探傷による欠陥位置情報
と表面探傷による欠陥位置情報との関係から欠陥
位置推定情報の信頼性を高める処理を概念的に示
す図である。第9図a,bは入射面の凹凸の影響
と超音波ビームの入射位置との関係を示す図であ
る。第10図は入射面の傾斜による見かけ上の屈
折角の変化を示す図である。第11図は従来の垂
直探傷法による不感帯を示す図である。第12図
は本発明に係る斜角探傷法による不感帯を示す図
である。第13図は電子走査アレイ型探触子の構
造概様を示す図である。第14図は,a,
b,cは電子走査アレイ型探触子による超音波
ビームの制御態様を示す図である。第15図は角
鋼片探傷時の超音波ビーム径とφ2横穴に対する
S/Nの関係を示す図である。第16図a,b,
cは角鋼片に対する電子セクター走査の様子を概
念的に示す図である。第17図は電子リニア走査
を行なうための回路構成例を示す図である。第1
8図a,b,cは角鋼片に対する電子リニア走査
の様子を概念的に示す図である。第19図は電子
セクター走査を行なうための回路構成例を示す図
である。
1……探触子、2……角鋼片、S……超音波ビ
ーム。
FIGS. 1A, 1B, and 1C are diagrams showing a comparison between electronic sector scanning and electronic sector+linear scanning. FIG. 2 is a diagram showing changes in the round-trip passage rate of longitudinal waves and transverse waves depending on the incident angle. FIG. 3 is a diagram showing a flaw detection area by longitudinal wave angle flaw detection according to the present invention. FIG. 4 is a diagram showing the relationship between the transducer element width and the maximum beam inclination angle of an electronic scanning probe. FIG. 5 and FIG. 6 are diagrams showing the arrangement of the probe with respect to the square steel piece. FIG. 7 is a diagram showing information processing and detection patterns for surface defect discrimination. FIG. 8 is a diagram conceptually showing a process for increasing the reliability of defect position estimation information based on the relationship between defect position information obtained by ultrasonic angle flaw detection and defect position information obtained by surface flaw detection. FIGS. 9a and 9b are diagrams showing the relationship between the influence of irregularities on the incident surface and the incident position of the ultrasonic beam. FIG. 10 is a diagram showing changes in the apparent angle of refraction due to the inclination of the incident surface. FIG. 11 is a diagram showing a dead zone according to the conventional vertical flaw detection method. FIG. 12 is a diagram showing a dead zone obtained by the oblique flaw detection method according to the present invention. FIG. 13 is a diagram showing the general structure of an electronically scanned array type probe. Figure 14 shows a,
b and c are diagrams showing how an ultrasonic beam is controlled by an electronically scanned array probe. FIG. 15 is a diagram showing the relationship between the ultrasonic beam diameter and the S/N for a φ2 horizontal hole during flaw detection of a square steel piece. Figure 16 a, b,
c is a diagram conceptually showing how electronic sector scanning is performed on a rectangular steel piece. FIG. 17 is a diagram showing an example of a circuit configuration for performing electronic linear scanning. 1st
8a, b, and c are diagrams conceptually showing the state of electronic linear scanning on a square steel piece. FIG. 19 is a diagram showing an example of a circuit configuration for performing electronic sector scanning. 1...Probe, 2...Square steel piece, S...Ultrasonic beam.
Claims (1)
傷法であつて、前記探触子を、角鋼片軸方向に垂
直な面内でその材表面から所定の距離で、かつ又
材表面に対して所定の角度でセツトし、前記探触
子を電子セクター走査に電子リニア走査を組み合
わせて走査することにより、前記材表面での入射
点を略一定にして、角鋼片の内部および入射面に
隣接する側面の表面層を探傷することを特徴とす
る電子セクター、電子リニア走査併用による角鋼
片の探傷法。1 Longitudinal wave angle flaw detection method using an electronically scanned array type probe, in which the probe is placed at a predetermined distance from the material surface in a plane perpendicular to the axial direction of a square steel piece, and also on the material surface. By setting the probe at a predetermined angle to the rectangular steel piece and scanning the probe by combining electronic sector scanning and electronic linear scanning, the incident point on the material surface is kept approximately constant, and the inside of the rectangular steel piece and the incident surface are A flaw detection method for square steel pieces using a combination of electronic sector and electronic linear scanning, which is characterized by detecting flaws on the surface layer of adjacent side surfaces.
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP57233944A JPS59116541A (en) | 1982-12-24 | 1982-12-24 | Method for detecting flaw of square steel piece by using both electronic sector scanning and electronic linear scanning |
US06/563,953 US4537073A (en) | 1982-12-24 | 1983-12-21 | Inspection method of square billet using electronic scanning |
CA000444221A CA1222314A (en) | 1982-12-24 | 1983-12-23 | Inspection method of square billet using electronic scanning |
DE19833346791 DE3346791A1 (en) | 1982-12-24 | 1983-12-23 | METHOD FOR TESTING A SQUARE STICK WITH ELECTRONIC SCANNING |
KR1019830006135A KR870001259B1 (en) | 1982-12-24 | 1983-12-23 | Steel piece inspection using electronic beam |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP57233944A JPS59116541A (en) | 1982-12-24 | 1982-12-24 | Method for detecting flaw of square steel piece by using both electronic sector scanning and electronic linear scanning |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS59116541A JPS59116541A (en) | 1984-07-05 |
JPH0146027B2 true JPH0146027B2 (en) | 1989-10-05 |
Family
ID=16963059
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP57233944A Granted JPS59116541A (en) | 1982-12-24 | 1982-12-24 | Method for detecting flaw of square steel piece by using both electronic sector scanning and electronic linear scanning |
Country Status (2)
Country | Link |
---|---|
JP (1) | JPS59116541A (en) |
KR (1) | KR870001259B1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2009041313A1 (en) * | 2007-09-28 | 2009-04-02 | Krautkramer Japan Co., Ltd | Ultrasonic flaw detecting method and its device |
WO2009084508A1 (en) * | 2007-12-27 | 2009-07-09 | Showa Denko K.K. | Ultrasonic flaw detection method for cast stick and ultrasonic flaw detection device |
JP2013011630A (en) * | 2012-10-16 | 2013-01-17 | Showa Denko Kk | Ultrasonic flaw inspection method for cast stick and ultrasonic flaw detection device |
JP2013156277A (en) * | 2008-03-31 | 2013-08-15 | Kjtd Co Ltd | Ultrasonic flaw detection method and device thereof |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB9808668D0 (en) * | 1998-04-24 | 1998-06-24 | Smiths Industries Plc | Monitoring |
CA2594965C (en) * | 2005-01-21 | 2010-04-27 | Fluor Technologies Corporation | Ultrasound phased array devices and methods for use with stainless steel |
JP6870980B2 (en) * | 2016-12-19 | 2021-05-12 | 株式会社東芝 | Ultrasonic inspection equipment, ultrasonic inspection method, and manufacturing method of joint block material |
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JPS5284884A (en) * | 1975-10-13 | 1977-07-14 | Commw Of Australia | Method of checking ultrasonic wave and device therefor |
JPS53140879A (en) * | 1977-05-13 | 1978-12-08 | Hitachi Ltd | Method of and device for transmitting and receiving electron2scan of ultrasonic wave |
JPS56126761A (en) * | 1980-03-12 | 1981-10-05 | Nippon Steel Corp | Ultrasonic flaw-detecting method for square bar |
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- 1982-12-24 JP JP57233944A patent/JPS59116541A/en active Granted
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5284884A (en) * | 1975-10-13 | 1977-07-14 | Commw Of Australia | Method of checking ultrasonic wave and device therefor |
JPS53140879A (en) * | 1977-05-13 | 1978-12-08 | Hitachi Ltd | Method of and device for transmitting and receiving electron2scan of ultrasonic wave |
JPS56126761A (en) * | 1980-03-12 | 1981-10-05 | Nippon Steel Corp | Ultrasonic flaw-detecting method for square bar |
Cited By (9)
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WO2009041313A1 (en) * | 2007-09-28 | 2009-04-02 | Krautkramer Japan Co., Ltd | Ultrasonic flaw detecting method and its device |
JP2013148597A (en) * | 2007-09-28 | 2013-08-01 | Kjtd Co Ltd | Ultrasonic flaw detection method and device thereof |
JP5279090B2 (en) * | 2007-09-28 | 2013-09-04 | 株式会社Kjtd | Ultrasonic flaw detection method and apparatus |
US8584526B2 (en) | 2007-09-28 | 2013-11-19 | Krautkramer Japan Co., Ltd. | Ultrasonic flaw detection method and ultrasonic flaw detection equipment |
WO2009084508A1 (en) * | 2007-12-27 | 2009-07-09 | Showa Denko K.K. | Ultrasonic flaw detection method for cast stick and ultrasonic flaw detection device |
JP2009156755A (en) * | 2007-12-27 | 2009-07-16 | Showa Denko Kk | Method and device for ultrasonically detecting flaw in cast rod |
JP2013156277A (en) * | 2008-03-31 | 2013-08-15 | Kjtd Co Ltd | Ultrasonic flaw detection method and device thereof |
JP5288291B2 (en) * | 2008-03-31 | 2013-09-11 | 株式会社Kjtd | Ultrasonic flaw detection method and apparatus |
JP2013011630A (en) * | 2012-10-16 | 2013-01-17 | Showa Denko Kk | Ultrasonic flaw inspection method for cast stick and ultrasonic flaw detection device |
Also Published As
Publication number | Publication date |
---|---|
KR870001259B1 (en) | 1987-06-29 |
KR840007180A (en) | 1984-12-05 |
JPS59116541A (en) | 1984-07-05 |
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