JPH09138222A - Ultrasonic inspection method for cast piece or rolled steel material - Google Patents
Ultrasonic inspection method for cast piece or rolled steel materialInfo
- Publication number
- JPH09138222A JPH09138222A JP7296561A JP29656195A JPH09138222A JP H09138222 A JPH09138222 A JP H09138222A JP 7296561 A JP7296561 A JP 7296561A JP 29656195 A JP29656195 A JP 29656195A JP H09138222 A JPH09138222 A JP H09138222A
- Authority
- JP
- Japan
- Prior art keywords
- defect
- inspected
- inspection
- reflected wave
- flaw part
- 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.)
- Withdrawn
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/11—Analysing solids by measuring attenuation of acoustic waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/04—Wave modes and trajectories
- G01N2291/044—Internal reflections (echoes), e.g. on walls or defects
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
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、垂直超音波探傷法
を用いて、鋳片又は圧延された鋼材の内部に存在する微
小な非金属介在物及び気泡を検査する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting minute non-metallic inclusions and bubbles present inside a cast or rolled steel material by using a vertical ultrasonic flaw detection method.
【０００２】[0002]
【従来の技術】近年、鉄鋼製品の品質に対する要求が厳
しくなるとともに、鋳片又は圧延された鋼材の内部に存
在する非金属介在物、気泡等の微小な欠陥を検出し、そ
の発生原因を明らかにする技術の重要性が高まってい
る。とくに、製鋼工程において欠陥を低減するための対
策をとる上で、これら微小な欠陥の数や位置を検出する
のみならず、その種類や大きさを知ることが重要になっ
てきている。2. Description of the Related Art In recent years, the demands on the quality of steel products have become strict, and minute defects such as non-metallic inclusions and air bubbles existing inside cast or rolled steel materials have been detected and the cause of occurrence has been clarified. The importance of the technology to make is increasing. In particular, in taking measures to reduce defects in the steelmaking process, it is becoming important not only to detect the number and position of these minute defects but also to know their type and size.
【０００３】これらの非金属介在物や気泡の数や大きさ
を正確に測定する方法としては、従来光学顕微鏡による
方法が一般的であったが、非破壊でかつ迅速に検査を行
うという目的から、近年超音波探傷法が注目されてい
る。As a method for accurately measuring the number and size of these non-metallic inclusions and bubbles, a method using an optical microscope has been generally used in the past, but for the purpose of performing non-destructive and quick inspection. Recently, ultrasonic flaw detection has been attracting attention.
【０００４】垂直超音波探傷法においては、探触子から
被検査物の表面に垂直に入射されたパルス状の超音波
が、被検査物の表面、欠陥部界面、被検査物底面で反射
されて探触子で検知され、時間遅れをもった一連のパル
ス状の反射波の信号波形が得られる。In the vertical ultrasonic flaw detection method, pulsed ultrasonic waves vertically incident on the surface of the object to be inspected from the probe are reflected on the surface of the object to be inspected, the interface of the defect portion, and the bottom surface of the object to be inspected. Is detected by the probe, and a signal waveform of a series of pulsed reflected waves with a time delay is obtained.
【０００５】このような反射波の信号波形においては、
表面反射波と欠陥部反射波との遅れ時間と被検査物内の
音速から、欠陥の深さ方法の位置を知ることはできる
が、単一の測定で、欠陥部の物質の種類やその大きさを
判断することは不可能であった。 また、欠陥の大きさ
を判定する方法としては、非検査物表面で探触子を走査
して各格子点で測定を行い、欠陥部反射波の検出される
格子点の拡がりから欠陥の大きさを判定する方法があ
る。しかし、この方法単独では欠陥部の物質の種類の判
定はできない。また微小な欠陥の場合には、格子間隔を
小さくとる必要があり、その結果、測定する格子点の総
数を極めて多くする必要がある。In the signal waveform of such a reflected wave,
Although the position of the defect depth method can be known from the delay time between the surface reflected wave and the reflected wave of the defect and the speed of sound in the object to be inspected, the type and size of the defect material can be determined by a single measurement. It was impossible to judge that. As a method of determining the size of the defect, the probe is scanned on the surface of the non-inspection object and the measurement is performed at each lattice point. There is a method to judge. However, this method alone cannot determine the type of substance in the defective portion. Further, in the case of minute defects, it is necessary to make the lattice spacing small, and as a result, it is necessary to make the total number of lattice points to be measured extremely large.
【０００６】さらに、微小な欠陥の場合には反射波の検
出感度を高める必要があり、欠陥部の周辺では散乱エコ
−を検知するため、欠陥部の大きさの正確な判定が困難
になるという問題があった。Further, in the case of a minute defect, it is necessary to enhance the detection sensitivity of the reflected wave, and since the scattering echo is detected around the defect portion, it becomes difficult to accurately determine the size of the defect portion. There was a problem.
【０００７】一方、欠陥の種類を判断する方法として、
特開平３−１０２２５８号公報に開示されているよう
に、欠陥部反射波の位相変化から、介在物による欠陥と
気泡による欠陥の分離・識別を行う方法がある。しかし
この方法では、全ての欠陥に対して反射エコ−の波形処
理を行い位相変化を算出するプロセスが必要な上に、反
射波の位相変化が識別可能な高感度の超音波探傷器を必
要とし、かつ適用しうる介在物の種類にある程度の制限
があるという問題がある。On the other hand, as a method of judging the type of defect,
As disclosed in Japanese Unexamined Patent Publication No. 3-102258, there is a method of separating / identifying defects due to inclusions and defects due to bubbles based on the phase change of the reflected wave of the defective portion. However, this method requires a process of calculating the phase change by performing the waveform processing of the reflection echo on all the defects, and also requires a highly sensitive ultrasonic flaw detector that can identify the phase change of the reflected wave. In addition, there is a problem that the type of inclusions that can be applied is limited to some extent.
【０００８】[0008]
【発明が解決しようとする課題】本発明は、上記のよう
な従来技術の問題点を解決するためになされたものであ
って、その目的とするところは、鋳片又は圧延された鋼
材の内部に存在する微小な介在物、気泡等の欠陥を垂直
超音波探傷法を用いて検査するに際して、欠陥部近傍で
探触子を走査して得られる一連の欠陥部反射信号波のエ
コ−高さの測定結果から、当該欠陥部の種類とその大き
さを判定する方法を提供することにある。SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art as described above, and the purpose thereof is to provide the inside of a cast or rolled steel material. When inspecting defects such as microscopic inclusions and bubbles existing in the vertical ultrasonic flaw detection method, the echo height of a series of defect signal waves obtained by scanning the probe in the vicinity of the defect The object of the present invention is to provide a method of determining the type and size of the defective portion from the measurement result of 1.
【０００９】[0009]
【課題を解決するための手段】本発明の発明者らは、上
記の課題を解決するための手段について種々研究を重ね
た結果、欠陥部反射信号波の強度ｅ、表面反射波と欠陥
部反射波との遅れ時間ｔ、被検査材内の音速ｃ及び欠陥
部の検査面への投影面積の円換算直径ｄの間に、下記
(1)式の関係があることを見出した。The inventors of the present invention have conducted various researches on means for solving the above-mentioned problems, and as a result, the intensity e of the reflected signal wave of the defect portion, the surface reflection wave and the reflection of the defect portion have been obtained. Between the delay time t with the wave, the sound velocity c in the inspected material, and the circle-converted diameter d of the projected area of the defect portion on the inspection surface,
We have found that there is a relationship of equation (1).
【００１０】本発明はこの知見に基づいてなされたもの
で、鋳片又は圧延された鋼材の内部に存在する非金属介
在物及び気泡を垂直超音波探傷法を用いて検査するに際
して、被検査材の表面上を所定の走査ピッチで探触子を
走査して非金属介在物又は気泡からの欠陥部反射波の強
度を測定し、下記(1)式の関係を用いて、該欠陥部に存
在する非金属介在物又は気泡の判別を行うと共に該欠陥
部の検査面への投影面積の円換算直径を判定することを
特徴とする鋳片又は圧延された鋼材の超音波検査法であ
る。The present invention has been made on the basis of this finding, and when inspecting non-metallic inclusions and bubbles existing inside a cast or rolled steel material using a vertical ultrasonic flaw detection method, the material to be inspected The probe is scanned at a predetermined scanning pitch on the surface of the to measure the intensity of the reflected wave of the defect part from the non-metallic inclusions or bubbles, and it is present in the defect part using the relationship of the following equation (1). The ultrasonic inspection method of a cast or rolled steel material is characterized in that the non-metallic inclusions or air bubbles are discriminated and the diameter of a projected area of the defective portion on the inspection surface in circle is determined.
【００１１】[0011]
【数２】 (Equation 2)
【００１２】ｄ：欠陥部の検査面への投影面積の円換算
直径 ｅ：欠陥部反射波の強度 ｃ：被検査材内の音速 ｔ：表面反射波と欠陥部反射波との遅れ時間 ｋ：欠陥部の物質の種類と計器特性によって定まる定数D: circle conversion diameter of projected area of defect on inspection surface e: intensity of defect reflected wave c: sound velocity in inspected material t: delay time between surface reflected wave and defect reflected wave k: A constant determined by the type of material in the defect and instrument characteristics
【００１３】[0013]
【発明の実施の形態】図１は、本発明を実施するための
垂直超音波探傷装置の例を示す図である。FIG. 1 is a diagram showing an example of a vertical ultrasonic flaw detector for carrying out the present invention.
【００１４】超音波探傷装置は、探触子１、超音波探傷
器５、操作駆動部７、信号演算処理部１０から構成され
ている。被検査材４は水２内に検査面を水平にして浸
漬、静置され、探触子の先端部は、超音波ビ−ム３の集
束レンズの水に換算した焦点距離だけ検査部分から離し
て水に浸漬される。The ultrasonic flaw detector comprises a probe 1, an ultrasonic flaw detector 5, an operation drive section 7, and a signal calculation processing section 10. The material 4 to be inspected is immersed in the water 2 with the inspection surface horizontal and allowed to stand still, and the tip of the probe is separated from the inspection portion by the focal length converted into water of the focusing lens of the ultrasonic beam 3. And soak in water.
【００１５】探触子の位置は、マイクロコンピュ−タ６
により制御される走査駆動部７によって設定される。探
触子を平面上ＸＹ方向に所定の走査ピッチで走査させ、
各格子点で欠陥エコ−強度の測定を行う。The position of the probe is determined by the microcomputer 6
It is set by the scan drive unit 7 controlled by. Scan the probe in a XY direction on a plane at a predetermined scanning pitch,
The defect eco-strength is measured at each grid point.
【００１６】図２は、垂直超音波探傷法における信号波
形の概念図である。この図に示すように、パルス状の超
音波ビ−ムを被検査材に入射して、被検査材の表面及び
欠陥部（非金属介在物又は気泡)から反射して帰ってき
た反射波のパルス信号を探触子１で受信する。受信した
信号には、欠陥部反射信号波の強度ｅ(以下「欠陥エコ
−強度」という)、表面反射波と欠陥部反射波との遅れ
時間ｔ(以下単に「遅れ時間」という)に関する情報が含
まれる。FIG. 2 is a conceptual diagram of a signal waveform in the vertical ultrasonic flaw detection method. As shown in this figure, a pulsed ultrasonic beam is incident on the material to be inspected, and the reflected wave returned from the surface of the material to be inspected and the defect (non-metallic inclusion or bubble) is returned. The probe 1 receives the pulse signal. The received signal includes information about the intensity e of the defect reflected signal wave (hereinafter referred to as “defect eco-intensity”) and the delay time t between the surface reflected wave and the defect reflected wave (hereinafter simply referred to as “delay time”). included.
【００１７】該信号は超音波探傷器５にて増幅され、マ
イクロコンピュ−タ６にて後述するような演算処理を行
って、メモリ−部８に蓄積され、出力装置９で所定の形
式に表示される。The signal is amplified by the ultrasonic flaw detector 5, processed by the microcomputer 6 as will be described later, accumulated in the memory section 8, and displayed in a predetermined format on the output device 9. To be done.
【００１８】本発明の方法の測定原理を以下に述べる。
すでに述べたごとく、欠陥部の検査面への投影面積の円
換算直径ｄ(以下単に「換算直径」という)と欠陥エコ−
強度ｅ、遅れ時間ｔ及び被検査材内の音速ｃとの間には
前記(１)式の関係がある。ここで、係数ｋは欠陥部の物
質の種類と計器特性によって定まる定数であるが、当然
のことながらｄ、ｅ、ｃ及びｔの単位によっても相違す
る。The measurement principle of the method of the present invention will be described below.
As described above, the projected area of the defect portion on the inspection surface has a circle-converted diameter d (hereinafter simply referred to as “converted diameter”) and the defect eco-
The intensity e, the delay time t, and the sound velocity c in the material to be inspected have the relationship of the above equation (1). Here, the coefficient k is a constant that is determined by the type of substance in the defective portion and the instrument characteristic, but naturally, it also differs depending on the units of d, e, c, and t.
【００１９】一般に(１)式における係数ｋは、鋼の音響
インピ−ダンスと欠陥部の物質の音響インピ−ダンスと
の差にほぼ比例する。すなわち、欠陥部の物質が非金属
介在物である場合の係数ｋ1と気泡である場合の係数ｋ2
との間には、下記(２)式に示す関係がある。Generally, the coefficient k in the equation (1) is approximately proportional to the difference between the acoustic impedance of steel and the acoustic impedance of the material of the defective portion. That is, the coefficient k 1 when the substance of the defect is a non-metallic inclusion and the coefficient k 2 when it is a bubble
And, there is a relationship shown in the following equation (2).
【００２０】 ｋ1＝ａ・ｋ2 ……(２) ａ＝(Ｗ−Ｗ1）(Ｗ＋Ｗ2)／(Ｗ−Ｗ2)(Ｗ＋Ｗ1) ここで、Ｗ：鋼の音響インピ−ダンス、Ｗ1：非金属介
在物の音響インピ−ダンス、Ｗ2：気体の音響インピ−
ダンスである。K 1 = a · k 2 (2) a = (W−W 1 ) (W + W 2 ) / (W−W 2 ) (W + W 1 ), where W: acoustic impedance of steel, W 1 : Acoustic impedance of non-metallic inclusions, W 2 : Acoustic impedance of gas
It's a dance.
【００２１】Ｗ、Ｗ1、Ｗ2の値は、それぞれおおよそ４
５、１５〜４２、0.0004であるから、ａの値は０．０３
〜０．５の範囲である。ｋ1、ｋ2の値の絶対値は、計器
特性例えば反射波信号の検出感度等によって異なるか
ら、一定の測定条件の下で標準試料などを用いて定めら
れるが、一回の測定内においてはほぼ一定であり、上記
(２)式の関係が維持される。The values of W, W 1 and W 2 are approximately 4 respectively.
5,15-42, 0.0004, so the value of a is 0.03
０．５0.5. The absolute values of k 1 and k 2 differ depending on the instrument characteristics such as the detection sensitivity of the reflected wave signal, so they are determined using a standard sample under certain measurement conditions, but within one measurement Almost constant and above
The relationship of equation (2) is maintained.
【００２２】本発明の方法においては、まず、所定の走
査ピッチでＸＹ方法に探触子を走査させ、各格子点で欠
陥エコ−強度の測定を行う。所定の水準以上の欠陥エコ
−の検出される点について、（１)式及び（２）式の関
係を用いて、欠陥部の物質が非金属介在物であった場合
の換算直径ｄ1((１)式にｋ1を代入して得た値)と気泡で
あった場合の換算直径ｄ2((１)式にｋ2を代入して得た
値)の両者を計算し、メモリ−部に記憶する。In the method of the present invention, first, the probe is scanned by the XY method at a predetermined scanning pitch, and the defect echo intensity is measured at each lattice point. Regarding the point at which a defect eco level equal to or higher than a predetermined level is detected, the converted diameter d 1 (((1) and (2)) when the substance of the defect part is a non-metallic inclusion is used. Both the value obtained by substituting k 1 into the equation 1) and the reduced diameter d 2 in the case of bubbles (the value obtained by substituting k 2 in the equation (1)) are calculated, and the memory part Remember.
【００２３】次いで、マイクロコンピュ−タ−内で、欠
陥部の拡がりに関する情報から欠陥部の大きさＤを判定
し、Ｄが前記ｄ1、ｄ2の値のいずれに近いかで、非金属
介在物であるか気泡であるかを判定する。(１)式よりｄ
1はｄ2の１．４〜５倍となるのでこの判定は比較的容易
である。Then, the size D of the defective portion is judged from the information on the spread of the defective portion in the microcomputer, and the non-metallic intervention is performed depending on whether D is close to the value of d 1 or d 2. It is determined whether it is an object or a bubble. From equation (1), d
Since 1 is 1.4 to 5 times d 2 , this determination is relatively easy.
【００２４】次に、欠陥部の拡がりの中で欠陥エコ−強
度即ち換算直径が最大の値を示す部位を選び、既に定め
た欠陥が非金属介在物であるか気泡であるかの情報と合
わせて、(１)式より欠陥部の換算直径を定める。一般に
欠陥部の周辺は散乱エコ−の影響があり、厳密な境界が
定め難いのに対して、本発明の方法では、欠陥に最も近
接する格子点での欠陥エコ−強度より直接換算直径を判
定するので、より精度の高い欠陥の大きさに関する情報
が得られる。Next, a portion showing the maximum value of the defect eco-strength, that is, the converted diameter, is selected in the spread of the defective portion and combined with the information which is already determined whether the defect is a non-metallic inclusion or a bubble. Then, the reduced diameter of the defective portion is determined from the equation (1). In general, the periphery of the defect portion is affected by the scattering echo, and it is difficult to define a strict boundary.However, in the method of the present invention, the directly converted diameter is determined from the defect eco-intensity at the lattice point closest to the defect. Therefore, more accurate information about the size of the defect can be obtained.
【００２５】当然のことながら、本発明の方法において
は、遅れ時間に関する情報から、各走査点における欠陥
の深さ方法の位置が求められる。一般には、厚み方向の
探傷範囲は、表面下０．４〜５ｍｍである。メモリ−部
に蓄えられた欠陥の種類、換算直径、深さ方向の位置等
の情報は、マイクロコンピュ−タで画像処理され、出力
装置９に表示される。検出される欠陥の最小の大きさ
は、探傷周波数に依存するが、１００ＭＨｚの場合、３
０μｍ程度の大きさの欠陥まで検出可能である。As a matter of course, in the method of the present invention, the position of the defect depth method at each scanning point is obtained from the information regarding the delay time. Generally, the flaw detection range in the thickness direction is 0.4 to 5 mm below the surface. Information such as the type of defect, the reduced diameter, and the position in the depth direction stored in the memory unit is image-processed by the microcomputer and displayed on the output device 9. The minimum size of the detected defect depends on the flaw detection frequency, but at 100 MHz, 3
It is possible to detect a defect having a size of about 0 μm.
【００２６】走査ピッチは、どの程度の大きさの欠陥ま
で検査するかに依存するが、一般には２５〜５００μｍ
程度である。なお、本発明の方法においては、全検査面
における走査ピッチは大きくし、欠陥部の周辺で散乱エ
コ−が検出された場合に、その周辺を小さな走査ピッチ
で検査するという手法をとることにより、全体の検査時
間を大巾に短縮することも可能である。The scanning pitch depends on how large a defect is inspected, but it is generally 25 to 500 μm.
It is about. In the method of the present invention, the scanning pitch on all the inspection surfaces is increased, and when a scattering echo is detected in the periphery of the defect portion, by taking a method of inspecting the periphery with a small scanning pitch, It is also possible to greatly reduce the overall inspection time.
【００２７】また、(２)式における音響インピ−ダンス
Ｗ1の値は、非金属介在物の組成によっても変化する。
例えば、Al2O3系介在物の場合はＷ1は４０程度、SiO2系
介在物の場合はＷ1は１５程度である。前者でのｋを
ｋ1、後者でのｋをｋ1′とすると、ａ′＝ｋ1／ｋ1′の
値は約０．１２となる。したがって、非金属介在物のサ
イズが比較的大きい(例えば、走査ピッチの２〜３倍以
上の)場合には、(１)式で算定される換算直径ｄと欠陥
部の拡がりから推定した欠陥部の大きさＤとを正確に比
較することにより、ある程度の精度で非金属介在物の組
成を判定することも可能である。The value of the acoustic impedance W 1 in the equation (2) also changes depending on the composition of the non-metallic inclusion.
For example, W 1 is about 40 in the case of Al 2 O 3 inclusions, in the case of SiO 2 inclusions W 1 is about 15. If the former k is k 1 and the latter k is k 1 ′, the value of a ′ = k 1 / k 1 ′ is about 0.12. Therefore, when the size of the non-metallic inclusion is relatively large (for example, 2 to 3 times the scanning pitch), the defect diameter estimated from the reduced diameter d calculated by the equation (1) and the defect extension is estimated. It is also possible to judge the composition of the non-metallic inclusions with a certain degree of accuracy by making an accurate comparison with the size D.
【００２８】なお、圧延鋼材で圧下比がある程度以上大
きい場合には、内部の気泡は圧着されていることが多
い。また、伸び易い非金属介在物は圧延方向に延伸され
た形状になっている。このような場合には、上記と異な
るデ−タの処理をすることがある。When the rolling ratio of the rolled steel material is large to some extent, the air bubbles inside are often pressed. Further, the non-metallic inclusions that are easily stretched have a shape stretched in the rolling direction. In such a case, data processing different from the above may be performed.
【００２９】[0029]
【実施例】水浸垂直超音波探傷器(自動Ｃスキャン)を用
いて、低炭アルミキルド鋼の連続鋳造鋳片よりサンプル
材を１ケ切り出して、本発明の方法による非金属介在物
及び気泡の検査を行った。サンプル材は、連連鋳継目部
のスラブ(厚み２５０mm)の巾方向中央部から採取した。
すなわち、Ｌ面(湾曲連鋳機における湾曲内側の面)側の
表面から厚み中心までの１２５mm長さで５０×５０mmサ
ンプル材を切り出した。EXAMPLE A sample material was cut out from a continuously cast slab of low carbon aluminum killed steel using a water immersion vertical ultrasonic flaw detector (automatic C-scan) to remove non-metallic inclusions and bubbles by the method of the present invention. An inspection was done. The sample material was taken from the widthwise central part of the slab (thickness 250 mm) at the continuous casting joint.
That is, a 50 × 50 mm sample material was cut out with a length of 125 mm from the surface on the L surface (the surface on the inside of the curve in a curved continuous casting machine) to the center of thickness.
【００３０】超音波探傷器の測定条件は、 探傷周波数：７５ＭＨｚ 表面からの焦点位置：１．５mm 厚み方向の探傷範囲：表面下０．５〜２．５mm 走査ピッチ：５０μｍ 走査面積：５０×２０mm である。The measurement conditions of the ultrasonic flaw detector are: flaw detection frequency: 75 MHz, focus position from the surface: 1.5 mm, flaw detection range in the thickness direction: 0.5 to 2.5 mm below the surface, scanning pitch: 50 μm, scanning area: 50 × 20 mm Is.
【００３１】本発明の検査方法と従来の光学顕微鏡によ
る検査方法（以下「従来法」という)とを比較するため
に、本発明の検査が終了したサンプル材を表面から１.
０、１．５、２．０mmの各位置で段削りし、同一検査範
囲に存在する非金属介在物及び気泡の大きさ別の個数を
光学顕微鏡で目視により計測した。In order to compare the inspection method of the present invention with the conventional inspection method using an optical microscope (hereinafter referred to as "conventional method"), the sample material on which the inspection of the present invention has been completed 1.
Stepping was performed at each position of 0, 1.5 and 2.0 mm, and the number of non-metallic inclusions and bubbles existing in the same inspection range according to size was visually measured with an optical microscope.
【００３２】本発明の検査方法については、コンピュ−
タメモリ−の情報をもとに、表面から１．０、１．５、
２．０mmの各位置を基準とし、この基準面のうえ、０〜
１００μｍの範囲からの欠陥部反射信号波のみを抽出
し、本発明の方法により判定した非金属介在物及び気泡
のそれぞれにつき、大きさ別の個数を計数した。Regarding the inspection method of the present invention, a computer
Based on the information in the memory, 1.0, 1.5,
Based on each position of 2.0 mm, 0 to 0 on this reference plane
Only the signal waves reflected by the defective portion within the range of 100 μm were extracted, and the number of each non-metallic inclusion and bubble determined by the method of the present invention was counted by size.
【００３３】図３に本発明の方法と従来法での非金属介
在物の大きさ別の個数の測定結果の比較を示す。また、
図４に気泡の大きさ別の個数の測定結果の比較を示す。
図３、図４における１ケのプロットは、所定の深さ方向
位置、所定の面積内で検出された非金属介在物又は気泡
の大きさ別の個数の総数で、被検査部分の鋼材重量１kg
当りに換算して表示した。FIG. 3 shows a comparison of the measurement results of the number of non-metallic inclusions by size according to the method of the present invention and the conventional method. Also,
FIG. 4 shows a comparison of measurement results of the number of bubbles according to size.
One plot in FIGS. 3 and 4 is the total number of non-metallic inclusions or bubbles detected within a predetermined area in a predetermined depth direction within a predetermined area, and the weight of the steel material in the inspected portion is 1 kg.
It was converted and displayed.
【００３４】図３、図４に見られるように、非金属介在
物及び気泡共に、大きさ別の個数は両測定方法で概ね対
応しており、この結果から、本発明の検査方法が十分実
用性があることが裏付けられた。As can be seen in FIGS. 3 and 4, the number of non-metallic inclusions and bubbles according to size generally correspond to each other by both measuring methods. From these results, the inspection method of the present invention is sufficiently practical. It was proved that there is a nature.
【００３５】[0035]
【発明の効果】本発明により、鋳片又は圧延された鋼材
の内部に存在する２５〜５０μｍ以上の大きさの非金属
介在物及び気泡の種別、大きさ、位置の判定が可能にな
り、非破壊で迅速な微小内部欠陥の検査が可能になっ
た。Industrial Applicability According to the present invention, it is possible to determine the type, size and position of non-metallic inclusions and bubbles having a size of 25 to 50 μm or more present inside cast slabs or rolled steel products. Destruction made it possible to quickly inspect small internal defects.
【図１】本発明を実施するための垂直超音波探傷装置の
例を示す図である。FIG. 1 is a diagram showing an example of a vertical ultrasonic flaw detector for implementing the present invention.
【図２】垂直超音波探傷法における信号波形の概念図で
ある。FIG. 2 is a conceptual diagram of a signal waveform in a vertical ultrasonic flaw detection method.
【図３】本発明の方法と従来法での、非金属介在物の大
きさ別の個数の測定結果の比較を示す図である。FIG. 3 is a diagram showing a comparison of measurement results of the number of non-metallic inclusions according to size according to the method of the present invention and the conventional method.
【図４】本発明の方法と従来法での、気泡の大きさ別の
個数の測定結果の比較を示す図である。FIG. 4 is a diagram showing a comparison of the measurement results of the number of bubbles by size according to the method of the present invention and the conventional method.
１ 探触子 ２ 水 ３ 超音波ビ−ム ４ 被検査材 ５ 超音波探傷器 ６ マイクロコンピュ−タ ７ 走査駆動部 ８ メモリ−部 ９ 出力装置 １０ 信号演算処理部 1 Probe 2 Water 3 Ultrasonic Beam 4 Inspected Material 5 Ultrasonic Flaw Detector 6 Micro Computer 7 Scanning Drive Section 8 Memory Section 9 Output Device 10 Signal Processing Section
Claims (1)
非金属介在物及び気泡を垂直超音波探傷法を用いて検査
するに際して、被検査材の表面上を所定の走査ピッチで
探触子を走査して非金属介在物又は気泡からの欠陥部反
射波の強度を測定し、下記(1)式の関係を用いて、該欠
陥部に存在する非金属介在物又は気泡の判別を行うと共
に該欠陥部の検査面への投影面積の円換算直径を判定す
ることを特徴とする鋳片又は圧延された鋼材の超音波検
査法。 【数１】 ｄ：欠陥部の検査面への投影面積の円換算直径 ｅ：欠陥部反射波の強度 ｃ：被検査材内の音速 ｔ：表面反射波と欠陥部反射波との遅れ時間 ｋ：欠陥部の物質の種類と計器特性によって定まる定数1. When inspecting non-metallic inclusions and bubbles present inside a cast slab or a rolled steel material by a vertical ultrasonic flaw detection method, the surface of the material to be inspected is probed at a predetermined scanning pitch. The intensity of the reflected wave from the non-metallic inclusion or bubble is measured by scanning the child, and the non-metallic inclusion or bubble present in the defective part is determined using the relationship of the following equation (1). At the same time, an ultrasonic inspection method of a cast or rolled steel material is characterized by determining a circle-converted diameter of a projected area of the defective portion on an inspection surface. (Equation 1) d: circle-converted diameter of the projected area of the defect on the inspection surface e: intensity of the reflected wave of the defect c: sound velocity in the material to be inspected t: delay time between the surface reflected wave and the reflected wave of the defect k: defect Constant determined by substance type and instrument characteristics
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7296561A JPH09138222A (en) | 1995-11-15 | 1995-11-15 | Ultrasonic inspection method for cast piece or rolled steel material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7296561A JPH09138222A (en) | 1995-11-15 | 1995-11-15 | Ultrasonic inspection method for cast piece or rolled steel material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09138222A true JPH09138222A (en) | 1997-05-27 |
Family
ID=17835145
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7296561A Withdrawn JPH09138222A (en) | 1995-11-15 | 1995-11-15 | Ultrasonic inspection method for cast piece or rolled steel material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09138222A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006284428A (en) * | 2005-04-01 | 2006-10-19 | Nippon Steel Corp | Method and device for detecting inclusion with nonlinear ultrasonic wave |
| DE19928547B4 (en) * | 1998-06-26 | 2007-12-27 | Denso Corp., Kariya | Method for producing a pressure sensor |
| JP2010066022A (en) * | 2008-09-08 | 2010-03-25 | Morinaga Milk Ind Co Ltd | Method of detecting sterilization start position in steam direct heating |
| KR101224964B1 (en) * | 2011-01-28 | 2013-01-22 | 현대제철 주식회사 | Apparatus for analysis pin hole distribution in slab and method therefor |
| WO2013183759A1 (en) * | 2012-06-08 | 2013-12-12 | 原子燃料工業株式会社 | Material diagnostic method |
| EP4043876A4 (en) * | 2019-10-09 | 2022-10-19 | NSK Ltd. | Method for evaluating purity of steel material |
-
1995
- 1995-11-15 JP JP7296561A patent/JPH09138222A/en not_active Withdrawn
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19928547B4 (en) * | 1998-06-26 | 2007-12-27 | Denso Corp., Kariya | Method for producing a pressure sensor |
| JP2006284428A (en) * | 2005-04-01 | 2006-10-19 | Nippon Steel Corp | Method and device for detecting inclusion with nonlinear ultrasonic wave |
| JP4610398B2 (en) * | 2005-04-01 | 2011-01-12 | 新日本製鐵株式会社 | Inclusion detection method and apparatus using nonlinear ultrasonic waves |
| JP2010066022A (en) * | 2008-09-08 | 2010-03-25 | Morinaga Milk Ind Co Ltd | Method of detecting sterilization start position in steam direct heating |
| KR101224964B1 (en) * | 2011-01-28 | 2013-01-22 | 현대제철 주식회사 | Apparatus for analysis pin hole distribution in slab and method therefor |
| WO2013183759A1 (en) * | 2012-06-08 | 2013-12-12 | 原子燃料工業株式会社 | Material diagnostic method |
| JP2013253914A (en) * | 2012-06-08 | 2013-12-19 | Nuclear Fuel Ind Ltd | Material diagnosis method |
| US10345274B2 (en) | 2012-06-08 | 2019-07-09 | Nuclear Fuel Industries, Limited | Material diagnostic method |
| EP4043876A4 (en) * | 2019-10-09 | 2022-10-19 | NSK Ltd. | Method for evaluating purity of steel material |
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