JP2531873B2 - Surface defect inspection method - Google Patents
Surface defect inspection methodInfo
- Publication number
- JP2531873B2 JP2531873B2 JP3188688A JP18868891A JP2531873B2 JP 2531873 B2 JP2531873 B2 JP 2531873B2 JP 3188688 A JP3188688 A JP 3188688A JP 18868891 A JP18868891 A JP 18868891A JP 2531873 B2 JP2531873 B2 JP 2531873B2
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- Japan
- Prior art keywords
- distance
- square steel
- defect
- probe
- ultrasonic
- 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.)
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- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
Description
【発明の詳細な説明】Detailed Description of the Invention
【０００１】[0001]
【産業上の利用分野】本発明は、表層領域内に存在する
内部欠陥の評定距離を求める超音波斜角法による表層欠
陥探傷方法の改善に係り、より詳しくは角鋼片の３〜４
ｍｍ深さまでの表層領域にある内部欠陥の位置を精度良
く評定し得るようにした超音波斜角法による表層欠陥探
傷方法に関するものである。FIELD OF THE INVENTION The present invention exists in the surface area.
It relates to improvement of surface defects inspection method by ultrasonic oblique angle method for obtaining the assessment distance internal defects, more particularly 3-4 corner steel strip
The present invention relates to a surface defect inspection method by an ultrasonic bevel method capable of accurately evaluating the position of an internal defect in a surface region up to a depth of mm .
【０００２】[0002]
【従来の技術】周知のように、角鋼片は、製品化するた
めにさらに二次加工されるが、この角鋼片の内部に微細
な介在物があると、二次加工段階において介在物の存在
に起因する加工割れや断線が発生したりすることが多々
ある。このような不具合発生防止対策として、製銑、製
鋼段階における介在物の除去及び介在物の混入防止の為
の炉外精錬技術と共に、微細な介在物の存在を検出する
検査技術の確立が必要不可欠である。2. Description of the Related Art As is well known, square steel pieces are further subjected to secondary working for commercialization. If fine inclusions are present inside the square steel pieces, the presence of inclusions in the secondary working stage. There are many cases where work cracking and disconnection due to As a countermeasure to prevent such defects, it is essential to establish an out-of-reactor refining technology to remove inclusions and prevent inclusions in the pig iron and steel making stages, as well as inspection technology to detect the presence of fine inclusions. Is.
【０００３】ところで、角鋼片等の素材に悪影響を及ぼ
す介在物はその素材段階から存在するものであるから、
二次加工前の素材の段階でこれらの介在物を検出するこ
とができれば二次加工後の製品の内部品質の保証が可能
になる。しかしながら、このような素材（以下、角鋼片
という）の内部欠陥は従来から超音波探傷によって検出
されているが、これら介在物は角鋼片の表層領域に介在
することが多いので、この表層領域内に生じるこれら介
在物に基づく内部欠陥を垂直法により確実に検出するこ
とは難しい。By the way, since the inclusions that adversely affect the material such as the square steel pieces exist from the material stage,
If these inclusions can be detected at the stage of the material before the secondary processing, the internal quality of the product after the secondary processing can be guaranteed. However, although internal defects of such a material (hereinafter referred to as square steel slab) have been conventionally detected by ultrasonic flaw detection, since these inclusions are often present in the surface layer region of the square steel slab, it is It is difficult to reliably detect the internal defect caused by these inclusions in the vertical method.
【０００４】つまり、超音波探触子（以下、探触子とい
う）を配置した面やその面と反対側の面に近接した位置
に内部欠陥があると、角鋼片の表面から反射された反射
超音波である反射エコーと、内部欠陥から反射された反
射超音波である欠陥エコーとがあるが、これらのエコー
が表面から反射されたものか、内部欠陥から反射された
ものかの判別が極めて困難であるためである。That is, if there is an internal defect near the surface on which the ultrasonic probe (hereinafter referred to as the "probe") is arranged, or at a position close to the surface opposite to the surface, the reflection reflected from the surface of the square steel piece. There are reflected echoes that are ultrasonic waves and defect echoes that are reflected ultrasonic waves that are reflected from internal defects, but it is extremely possible to distinguish whether these echoes are reflected from the surface or internal defects. Because it is difficult.
【０００５】そのため、角鋼片の表面に対して探触子を
傾斜させて配置する、いわゆる超音波斜角法が導入され
るようになってきている。超音波斜角法としては、例え
ば特開昭５６−１２９８５２号公報にて開示された探傷
技術が公知である。以下、この技術を探触子配置説明図
の図３と、その作用説明図の図４ａと、エコー状況説明
図の図４ｂとを参照しながら説明する。For this reason, a so-called ultrasonic beveling method has been introduced in which the probe is arranged to be inclined with respect to the surface of the square steel piece. As the ultrasonic bevel method, for example, the flaw detection technique disclosed in Japanese Patent Laid-Open No. 56-129852 is known. Hereinafter, this technique will be described with reference to FIG. 3 which is a diagram for explaining the arrangement of the probe, FIG. 4a which is a diagram for explaining its operation, and FIG. 4b which is a diagram for explaining an echo situation.
【０００６】上記の探傷技術は、図３に示すように、角
鋼片１の上面の外方に４個の探触子Ｓ1 ，Ｓ2 ，Ｓ3 ，
Ｓ4 をこの角鋼片１の幅方向の中心位置では垂直に、ま
たこの角鋼片１の幅方向の中心から外方にはづれた位置
になるほどその上面に対して傾斜させて配設している。
従って、これら探触子Ｓ1 ，Ｓ2 ，Ｓ3 ，Ｓ4 から角鋼
片１の底面側に向かって超音波を発信し、そして反射し
て帰ってきた反射超音波、所謂エコーを検出することに
よって内部欠陥の位置を評定する。As shown in FIG. 3, the above-described flaw detection technique uses four probes S 1 , S 2 , S 3 ,
S 4 is arranged vertically at the center position of the square steel piece 1 in the width direction, and is inclined with respect to the upper surface of the square steel piece 1 as it is positioned outward from the center of the square steel piece 1 in the width direction. .
Therefore, ultrasonic waves are transmitted from these probes S 1 , S 2 , S 3 , S 4 toward the bottom side of the square steel piece 1, and reflected ultrasonic waves that are reflected and returned, so-called echoes are detected. The position of the internal defect is evaluated by.
【０００７】検出される超音波の中には、欠陥エコーの
他に送信部から発信される送信パルス、角鋼片２の上面
から反射される上面エコーTE、底面から反射される底面
エコーとがあるので、検出された時点における時間差に
よって、何に起因して生じたエコーかを確実に判別して
内部欠陥を評定する必要がある。In addition to the defect echo, the ultrasonic waves detected include a transmission pulse transmitted from the transmission section, a top echo TE reflected from the upper surface of the square steel piece 2, and a bottom echo reflected from the bottom surface. Therefore, it is necessary to evaluate the internal defect by surely discriminating what caused the echo based on the time difference at the time of detection.
【０００８】即ち、図４ａと図４ｂとに示すように、角
鋼片１に内部欠陥Ｆ1 ，Ｆ2 があるとすると、これらの
内部欠陥Ｆ1 ，Ｆ2 により反射された欠陥エコーｆ1 、
ｆ2とが検出されることになるが、この場合に内部欠陥
Ｆ1 、Ｆ2 の位置は以下のようにして評定される。つま
り、この角鋼片１の上面から反射された表面エコーTEが
検出されてから、内部欠陥Ｆ1 ，Ｆ2 から反射された欠
陥エコーｆ1 、ｆ2 が検出されるまでの時間をｔF とす
れば、この角鋼片１の上面からこの内部欠陥までの距離
Ｌは式Ｌ＝Ｃ・（ｔF ／２）求められる。なお、上記式
中において英文字で記載したＣは角鋼片２中を伝播する
超音波の音速を示している。That is, as shown in FIGS. 4a and 4b, assuming that the square steel piece 1 has internal defects F 1 and F 2 , defect echoes f 1 reflected by these internal defects F 1 and F 2 ,
f 2 will be detected, and in this case, the positions of the internal defects F 1 and F 2 are evaluated as follows. That is, the time from the detection of the surface echo TE reflected from the upper surface of the square steel piece 1 to the detection of the defect echoes f 1 and f 2 reflected from the internal defects F 1 and F 2 is defined as t F. Then, the distance L from the upper surface of the square steel piece 1 to the internal defect is obtained by the equation L = C · (t F / 2). In the above formula, C, which is written in English letters, indicates the speed of sound of ultrasonic waves propagating in the square steel piece 2.
【０００９】ところが、例えば内部欠陥Ｆ1 ，Ｆ2 とが
探触子Ｓ4 から等距離離れた位置にある場合、探触子Ｓ
4 から発信された超音波が角鋼片１の内部に入射すると
きの屈折角をθとし、この角鋼片１の側面から超音波ビ
ーム入射位置までの距離をＤとすると、この側面からこ
れら内部欠陥Ｆ1 ，Ｆ2 までの深さｄは全て式ｄ＝Ｄ−
Ｃ・（ｔF ／２）・ｓｉｎθで表され、この側面から内
部欠陥の位置までの深さｄを判別することができないと
いう問題があった。このような問題は、実用上角鋼片２
の面当たりの探触子のチャンネル数を２〜４程度しか配
置することができず、指向角の広い超音波を使用せざる
を得ないということに起因している。However, for example, when the internal defects F 1 and F 2 are at positions equidistant from the probe S 4 , the probe S
Let θ be the refraction angle when the ultrasonic waves emitted from 4 enter the square steel piece 1, and let D be the distance from the side surface of the square steel piece 1 to the ultrasonic beam incident position. The depths d up to F 1 and F 2 are all expressed by the equation d = D-
It is represented by C · (t F / 2) · sin θ, and there is a problem that the depth d from this side surface to the position of the internal defect cannot be determined. Such a problem is caused by the square steel piece 2 in practical use.
This is because it is possible to arrange only about 2 to 4 channels of the probe per surface, and there is no choice but to use ultrasonic waves having a wide directional angle.
【００１０】そこで、本出願人は特開昭５９−１１６５
４１号公報にて、上記したような欠点を改善する為の表
層欠陥探傷技術を提案した。以下、この技術の例を、超
音波斜角法における探触子配置説明図の図５により概説
すると、角鋼片１の上面側にアレイ型の探触子Ｓ1 を傾
斜させて配置したもので、この傾斜したこの探触子Ｓ1
から超音波を発信し、反射して帰ってきたエコーによっ
て、例えば探傷領域２における欠陥の有無を評定するも
のである。Therefore, the present applicant has filed Japanese Patent Application Laid-Open No. 59-1165.
In Japanese Patent Publication No. 41, a surface layer defect flaw detection technique for improving the above-mentioned defects is proposed. Hereinafter, an example of this technique will be outlined with reference to FIG. 5 which is a diagram for explaining a probe arrangement in the ultrasonic bevel method. It is assumed that the array type probe S 1 is arranged on the upper surface side of the square steel piece 1 while being inclined. , This inclined probe S 1
For example, the presence or absence of a defect in the flaw detection area 2 is evaluated by an ultrasonic wave that is transmitted from the ultrasonic wave and is reflected and returned.
【００１１】このようにして検出されるエコーには、前
記斜角法の場合と同様に、欠陥エコーの他に送信エコ
ー、角鋼片１の上面で反射する上面エコーTEがあるが、
前記アレイ型の探触子Ｓ1 から発信される超音波ビーム
を、高速かつ任意に偏向、集束させることができるの
で、この偏向角度と集束角度とから角鋼片１の内部欠陥
の位置を容易に評定することができる。The echoes thus detected include the transmission echo and the upper surface echo TE reflected on the upper surface of the square steel piece 1 in addition to the defect echo, as in the case of the oblique angle method.
Since the ultrasonic beam emitted from the array type probe S 1 can be deflected and focused at high speed and arbitrarily, the position of the internal defect of the square steel piece 1 can be easily determined from the deflection angle and the focusing angle. Can be rated.
【００１２】しかしながら、角鋼片それ自体は中間製品
で二次加工製品でないので、このような角鋼片の表面形
状精度が二次加工後の棒鋼、線材あるいは板材等の製品
のそれと比較して良くないため、このような斜角法では
中間製品の表面形状精度に起因して数ｍｍ程度の誤差が
生じてしまうという課題が生じていた。つまり、角鋼片
から圧延されて製品となった線材、棒鋼等が、例えば二
次加工メーカで冷間或いは熱間で鍛造されるときに、最
も問題になるのは加工度が高い表面から３〜４ｍｍ深さ
までの表層領域であり、この表層領域内の欠陥の位置を
精度良く評定する必要がある為に他ならない。However, since the square steel piece itself is an intermediate product and not a secondary processed product, the surface shape accuracy of such a square steel piece is not good as compared with that of a product such as a steel bar, wire rod or plate material after secondary processing. Therefore, such an oblique angle method has a problem that an error of about several mm occurs due to the surface shape accuracy of the intermediate product. That is, when a wire rod, a steel bar, or the like, which is rolled into a product from a square steel piece, is forged cold or hot by, for example, a secondary processing maker, the most problematic problem is 3 to 3 It is a surface layer area up to a depth of 4 mm, and the position of the defect in this surface layer area must be evaluated with high precision, and this is nothing more than this.
【００１３】そこで、本出願人はさらに特願平１−３２
１９９号にて３〜４ｍｍ深さまでの表層領域における内
部欠陥を効果的に評定し得る表層欠陥探傷方法を提案し
た。以下、その概要を図６ａと図６ｂとを参照しながら
説明すると、その概要説明図の図６ａにおいて、内部欠
陥Ｆを検出すべき表層領域２側の垂直側面から所定距離
離れた角鋼片１の上面に斜角探触子Ｓを配設し、この斜
角探触子Ｓから屈折角θで超音波を発信すると、エコー
状況説明図の図６ｂに示すように、表面エコー（Ｓエコ
ー）と欠陥エコー（Ｆエコー）とコーナーエコーとが検
出される。Therefore, the present applicant has further filed Japanese Patent Application No. 1-32.
No. 199 proposed a surface defect inspection method capable of effectively evaluating internal defects in the surface region up to a depth of 3 to 4 mm. Hereinafter, the outline thereof will be described with reference to FIGS. 6a and 6b. In FIG. 6a of the outline explanatory diagram, the square steel piece 1 separated from the vertical side surface on the surface layer region 2 side where the internal defect F is to be detected by a predetermined distance is shown. When a bevel probe S is arranged on the upper surface and ultrasonic waves are transmitted from the bevel probe S at a refraction angle θ, a surface echo (S echo) is generated as shown in FIG. A defect echo (F echo) and a corner echo are detected.
【００１４】そして、内部欠陥Ｆまでの垂直方向距離Ｘ
w ，つまり評定距離Ｘw を、Ｘw ＝Ｃ・（ｔF ／２）ｃ
ｏｓθの計算式で求めるようにしている。但し、Ｃは鋼
中を伝播する超音波の音速であり、またｔF は上記と同
様に音速Ｃの超音波が角鋼片の表面から内部欠陥まで到
達するのに要する所要時間である。Then, the distance X in the vertical direction to the internal defect F
w , that is, the rating distance X w , X w = C · (t F / 2) c
The calculation formula for osθ is used. However, C is the sound velocity of the ultrasonic wave propagating in the steel, and t F is the time required for the ultrasonic wave of the sound velocity C to reach the internal defect from the surface of the square steel piece, as described above.
【００１５】[0015]
【発明が解決しようとする課題】ところが、図６ａから
良く理解されるように、斜角探触子Ｓを配設した位置か
ら内部欠陥Ｆまでの評定距離Ｘw は、同図中にＡＯＢで
示される円弧上に内部欠陥Ｆがあれば全て同じと評定さ
れてしまうので、計算で求められる評定距離Ｘw の誤差
が大きいという解決すべき課題が生じてきた。However, as is well understood from FIG. 6A, the evaluation distance X w from the position where the bevel probe S is arranged to the internal defect F is AOB in the figure. If there is an internal defect F on the arc shown, all of them will be evaluated as the same. Therefore, there has been a problem to be solved that the error of the evaluation distance X w calculated is large.
【００１６】従って、本発明の目的とするところは、よ
り高精度で角鋼片の表層領域における内部欠陥を評定す
ることを可能ならしめる超音波斜角法による表層欠陥探
傷方法の提供にある。Therefore, an object of the present invention is to provide a surface defect inspection method by the ultrasonic bevel method which makes it possible to evaluate internal defects in the surface region of a square steel piece with higher accuracy.
【００１７】[0017]
【課題を解決するための手段】本発明は上記課題に鑑み
てなされたものであって、従って本発明に係る超音波斜
角法による表層欠陥探傷方法の要旨は、角鋼片の所定深
さ範囲の表層領域側の垂直面から所定距離離れた角鋼片
の上面に探触子を配設し、この探触子から超音波を発信
して角鋼片の表層領域内の内部欠陥までの距離を求める
と共に、この表層領域側の垂直面に沿う方向の上面から
内部欠陥の位置までの垂直距離である評定距離を求める
超音波斜角法による表層欠陥探傷方法において、前記表
層領域の層厚を２ｂとし、角鋼片の表層領域側の垂直面
から探触子までの距離をａとし、伝播速度Ｃの超音波が
入射されて表層領域内の内部欠陥により反射して検出さ
れるまでの時間をｔF としたとき、｛（Ｃ・ｔF ／２)2
−（ａ−ｂ）2 ｝1/2 の計算式で前記評定距離を求める
ことを特徴とする。SUMMARY OF THE INVENTION The present invention was made in view of the above problems, therefore the gist of the surface layer defects testing method by ultrasonic oblique angle method according to the present invention, at Teifuka the angular steel strip Square steel slabs separated by a specified distance from the vertical surface on the surface layer area side of the range
A probe is placed on the upper surface of the and the ultrasonic wave is transmitted from this probe.
The distance to the internal defect in the surface area of the square billet
Along with the upper surface in the direction along the vertical surface on the surface layer area side
Obtaining a rating distance, which is the vertical distance to the position of the internal defect. <br /> In the surface defect inspection method by the ultrasonic bevel method, the layer thickness of the surface region is set to 2b, and the vertical surface of the square steel piece on the surface region side When the distance to the probe is a and the time until an ultrasonic wave having a propagation velocity C is incident and reflected by an internal defect in the surface layer region and detected is t F , {(C · t F / 2) 2
It is characterized in that the rating distance is obtained by a calculation formula of − (ab) 2 } 1/2 .
【００１８】[0018]
【作用】本発明に係る超音波斜角法による表層欠陥探傷
方法によれば、表層領域側の側面と平行な内部欠陥の位
置までの距離である評定距離Ｘw ＝｛（ｔF ・Ｃ／２)2
−（ａ−ｂ）2 ｝1/2 は簡単なピタゴラスの定理により
求められるが、この計算式によれば、表層領域の幅２ｂ
の１／２のｂが用いられるので、図６ａで説明した円弧
距離ＡＯＢを短くすることができる。According to the surface defect inspection method by the ultrasonic bevel method according to the present invention, the evaluation distance X w = {(t F · C / which is the distance to the position of the internal defect parallel to the side surface on the surface region side. 2) 2
-(Ab) 2 } 1/2 can be obtained by a simple Pythagorean theorem, and according to this calculation formula, the width 2b of the surface layer region is
Since half of b is used, the arc distance AOB described in FIG. 6a can be shortened.
【００１９】[0019]
【実施例】以下、本発明に係る実施例を、斜角探触子配
置説明図の図１と、内部欠陥位置の評定距離Ｘw の長さ
に対する評定距離Ｘw と実際の内部欠陥位置との評定距
離誤差説明図の図２（縦軸に誤差を、横軸に評定距離Ｘ
w をとって示している）を参照しながら説明する。EXAMPLE An example according to the present invention will now be described with reference to FIG. 1 which is an oblique probe arrangement explanatory diagram, and the evaluation distance X w with respect to the length of the evaluation distance X w of the internal defect position and the actual internal defect position. Fig. 2 of the rating distance error diagram (the vertical axis shows the error and the horizontal axis shows the rating distance X
w is shown).
【００２０】図１において示す符号Ｓは、角鋼片１の層
厚２ｄの限定した表層領域２における内部欠陥Ｆの探傷
を目的として、表層領域２側の側面から距離ａ離れた位
置の上面に配設した屈折角θが２０°、６ｄＢの指向角
ψが１２°の斜角探触子であって、所謂超音波斜角法に
よって角鋼片１の表層領域２に存在する内部欠陥Ｆを検
出するものである。そして、斜角探触子Ｓから伝播速度
Ｃの超音波が入射されて、表層領域２内の内部欠陥Ｆに
より反射して検出されるまでの時間をｔF としたとき
に、この表層領域２側の側面に沿う方向の内部欠陥Ｆの
位置までの距離、即ち評定距離Ｘw を｛（Ｃ・ｔF ／
２)2−（ａ−ｂ）2 ｝1/2 の計算式で求めることとし
た。Reference symbol S shown in FIG. 1 is arranged on the upper surface at a position away from the side surface on the side of the surface layer region 2 for the purpose of flaw detection of the internal defect F in the surface layer region 2 having a limited layer thickness 2d of the square steel piece 1. It is an oblique probe having a refraction angle θ of 20 ° and a directivity angle ψ of 6 dB of 12 °, and detects an internal defect F existing in a surface layer region 2 of a square steel piece 1 by a so-called ultrasonic oblique angle method. It is a thing. Then, when the time until the ultrasonic wave of the propagation velocity C is incident from the bevel probe S and reflected by the internal defect F in the surface layer region 2 to be detected is t F , this surface layer region 2 The distance to the position of the internal defect F in the direction along the side surface on the side, that is, the evaluation distance X w is {(C · t F /
2) 2- (a-b) 2 } 1/2 was calculated.
【００２１】つまり、発明者等は特願平１−３２１９９
号にて提案した如く、表層部のみの欠陥を抽出している
にも係わらず、評定距離Ｘw ＝Ｃ・（ｔF ／２）ｃｏｓ
θで計算すると誤差が大きいので、位置評定においては
欠陥の存在深さを限定表層厚さ２ｂの中央ｂと仮定して
計算することにより精度向上を図ったものである。That is, the inventors of the present invention have filed Japanese Patent Application No. 1-32199.
As proposed in No. 5, the evaluation distance X w = C · (t F / 2) cos, even though the defects of only the surface layer are extracted.
Since the error is large when calculated by θ, in the position evaluation, the accuracy is improved by assuming that the existence depth of the defect is the center b of the limited surface layer thickness 2b.
【００２２】いま、角鋼片１の一辺の寸法を１６０ｍｍ
とし、上記距離ａを４０ｍｍとし、また限定した表層領
域２の層厚２ｄを４ｍｍとし、そして表層領域２側の側
面表皮下０ｍｍの欠陥と、表皮下４ｍｍの欠陥の評定距
離の誤差を求めると共に、従来法（Ｘw ＝（Ｃ・ｔF ／
２）ｃｏｓθ）によっても評定距離Ｘw を求めて、両者
の評定距離の誤差Δｘを比較した。Now, the size of one side of the square steel piece 1 is 160 mm.
The distance a is set to 40 mm, the layer thickness 2d of the limited surface layer region 2 is set to 4 mm, and the error of the evaluation distance between the defect of 0 mm on the side surface epidermis on the surface layer region 2 side and the defect of 4 mm on the subdermal surface is calculated. , The conventional method (X w = (C · t F /
2) The evaluation distance X w was also obtained by cos θ), and the error Δx between the evaluation distances of both was compared.
【００２３】その結果は、図２（本法による場合を実線
で、また従来法による場合を破線でそれぞれ示してい
る）に示すとおりであって、本法では評定距離Ｘw が短
くなるにつれて若干誤差範囲が大きくなる傾向があるも
のの、評定距離Ｘw の誤差Δｘは高々±１．５ｍｍ以内
であった。即ち、従来法では一辺の長さが１６０ｍｍの
角鋼片１の場合、評定距離Ｘw が短い６０ｍｍで誤差Δ
ｘ＝＋７．２〜＋１０．２ｍｍ、評定距離が長い１５０
ｍｍで誤差Δｘ＝−５．５〜−４．５ｍｍと誤差が大き
く、評定距離により誤差が大きく変化することが判る。
それに対して、本法では評定距離に係わらず誤差は±
１．５ｍｍと安定している。The results are shown in FIG. 2 (the case of the present method is shown by a solid line and the case of the conventional method is shown by a broken line). In the present method, the evaluation distance X w becomes slightly smaller as the evaluation distance X w becomes shorter. Although the error range tends to be large, the error Δx of the evaluation distance X w was within ± 1.5 mm at most. That is, in the conventional method, in the case of the square steel piece 1 having a side length of 160 mm, the evaluation distance X w is 60 mm and the error Δ is small.
x = + 7.2 to + 10.2mm, long rating distance 150
It can be seen that there is a large error Δx = −5.5 to −4.5 mm in mm, and the error greatly changes depending on the rating distance.
On the other hand, in this method, the error is ± regardless of the rating distance.
It is stable at 1.5 mm.
【００２４】このように、本発明によれば限定された表
層領域２における内部欠陥Ｆの位置をより高精度で評定
し得るので、表層欠陥探傷検査技術レベルの向上が可能
になると共に、表層欠陥の位置評定精度が優れていて同
欠陥をグラインダ等で除去しようとする場合範囲を狭く
限定できるので、内部欠陥除去作業の所要時間を大幅に
短縮することが可能になる。As described above, according to the present invention, the position of the internal defect F in the limited surface layer region 2 can be evaluated with higher accuracy, so that the level of surface defect inspection technology can be improved and the surface layer defect can be improved. Since the position evaluation accuracy is excellent and the defect can be removed with a grinder or the like, the range can be narrowed, so that the time required for the internal defect removal work can be significantly shortened.
【００２５】[0025]
【発明の効果】以上詳述したように、本発明になる斜角
法による表層欠陥探傷方法による内部欠陥の位置までの
評定距離Ｘw ＝｛（ｔF ・Ｃ／２)2−（ａ−ｂ）2 ｝
1/2 の計算式によれば、表層領域の幅２ｂの１／２のｂ
を用いることによって、図６ｂで説明したＡＯＢの円弧
距離に相当する距離が短くなる結果、Ｘw の誤差を少な
くすることができるので、表層欠陥探傷精度の向上と二
次製品の不良防止とに対して極めて多大な効果を期待す
ることができる。As described in detail above, the evaluation distance X w = {(t F · C / 2) 2 − (a− to the position of the internal defect by the surface defect inspection method by the oblique angle method according to the present invention. b) 2 }
According to half of the equation, 1/2 of the b width 2b of the surface layer region
As a result of shortening the distance corresponding to the arc distance of AOB described in FIG. 6B, it is possible to reduce the error of X w , so that it is possible to improve the accuracy of surface defect inspection and prevent the defect of the secondary product. On the other hand, an extremely great effect can be expected.
【図１】本発明の実施例に係る超音波斜角法における斜
角探触子配置説明図である。FIG. 1 is an explanatory view of a bevel probe arrangement in an ultrasonic bevel method according to an embodiment of the present invention.
【図２】本発明の実施例に係る超音波斜角法における評
定距離誤差説明図である。FIG. 2 is an explanatory diagram of a rating distance error in the ultrasonic bevel method according to the embodiment of the present invention.
【図３】従来例１に係る探傷技術の探触子配置説明図で
ある。FIG. 3 is an explanatory diagram of probe arrangement of a flaw detection technique according to Conventional Example 1.
【図４】図ａは従来例１に係る探傷技術の作用説明図で
あり、また図ｂはエコー状況説明図である。FIG. 4A is an operation explanatory view of the flaw detection technique according to Conventional Example 1, and FIG. 4B is an echo situation explanatory view.
【図５】従来例２に係る探傷技術の探触子配置説明図で
ある。FIG. 5 is an explanatory diagram of probe arrangement of a flaw detection technique according to Conventional Example 2.
【図６】図ａは従来例３に係る探傷技術の概要説明図で
あり、また図ｂはエコー状況説明図である。6A is a schematic explanatory diagram of a flaw detection technique according to Conventional Example 3, and FIG. 6B is an explanatory diagram of an echo situation.
１…角鋼片 ２…層厚が限定された表層領域 Ｃ…鋼中を伝播する超音波の音速 Ｆ…内部欠陥 Ｓ…斜角探触子 Ｘw …評定距離1 ... ultrasonic sound velocity F 2 ... layer thickness steel strip corners propagate surface layer region C ... in steel a limited ... internal defects S ... angle probe X w ... assessment distance
Claims (1)
直面から所定距離離れた角鋼片の上面に探触子を配設
し、この探触子から超音波を発信して角鋼片の表層領域
内の内部欠陥までの距離を求めると共に、この表層領域
側の垂直面に沿う方向の上面から内部欠陥の位置までの
垂直距離である評定距離を求める超音波斜角法による表
層欠陥探傷方法において、前記表層領域の層厚を２ｂと
し、角鋼片の表層領域側の垂直面から探触子までの距離
をａとし、伝播速度Ｃの超音波が入射されて表層領域内
の内部欠陥により反射して検出されるまでの時間をｔF
としたとき、｛（Ｃ・ｔF ／２)2−（ａ−ｂ）2 ｝1/2
の計算式で前記評定距離を求めることを特徴とする超音
波斜角法による表層欠陥探傷方法。1. A vertical surface layer region side of the Teifuka range at the corners billet
A probe is placed on the upper surface of a square steel piece that is a certain distance from the face
Then, ultrasonic waves are transmitted from this probe and the surface layer area of the square steel piece is
The distance to the internal defect in the
From the top surface in the direction along the vertical surface of the side to the position of the internal defect
In the surface defect inspection method by the ultrasonic bevel method for obtaining the evaluation distance which is the vertical distance, the layer thickness of the surface region is 2b, and the distance from the vertical surface of the square steel piece on the surface region side to the probe is a, The time taken for an ultrasonic wave of propagation velocity C to be incident and reflected by an internal defect in the surface layer region to be detected is t F
Then, {(C · t F / 2) 2 − (a−b) 2 } 1/2
Surface defect inspection method by ultrasonic oblique angle method and obtaining the assessment distance formula.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3188688A JP2531873B2 (en) | 1991-07-29 | 1991-07-29 | Surface defect inspection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3188688A JP2531873B2 (en) | 1991-07-29 | 1991-07-29 | Surface defect inspection method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0534320A JPH0534320A (en) | 1993-02-09 |
| JP2531873B2 true JP2531873B2 (en) | 1996-09-04 |
Family
ID=16228097
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3188688A Expired - Lifetime JP2531873B2 (en) | 1991-07-29 | 1991-07-29 | Surface defect inspection method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2531873B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001153846A (en) * | 1999-11-29 | 2001-06-08 | Tokimec Inc | Flaw determination method and device for body to be inspected |
| JP2001153850A (en) * | 1999-11-29 | 2001-06-08 | Tokimec Inc | Image display method and device for ultrasonic flaw detection |
-
1991
- 1991-07-29 JP JP3188688A patent/JP2531873B2/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001153846A (en) * | 1999-11-29 | 2001-06-08 | Tokimec Inc | Flaw determination method and device for body to be inspected |
| JP2001153850A (en) * | 1999-11-29 | 2001-06-08 | Tokimec Inc | Image display method and device for ultrasonic flaw detection |
| JP4500391B2 (en) * | 1999-11-29 | 2010-07-14 | 東京計器株式会社 | Ultrasonic flaw detection image display method and ultrasonic flaw detection image display device |
| JP4500390B2 (en) * | 1999-11-29 | 2010-07-14 | 東京計器株式会社 | Inspection object wound determination method and inspection object damage determination apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0534320A (en) | 1993-02-09 |
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