JPH08178867A - Flat steel hot flaw-detecting device - Google Patents
Flat steel hot flaw-detecting deviceInfo
- Publication number
- JPH08178867A JPH08178867A JP33813594A JP33813594A JPH08178867A JP H08178867 A JPH08178867 A JP H08178867A JP 33813594 A JP33813594 A JP 33813594A JP 33813594 A JP33813594 A JP 33813594A JP H08178867 A JPH08178867 A JP H08178867A
- Authority
- JP
- Japan
- Prior art keywords
- flat steel
- light
- line sensor
- flaw
- flaw detector
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B38/00—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、板バネ等の材料となる
平鋼の熱間圧延時に生成される掻疵をオンラインで検出
する装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for online detection of scratches produced during hot rolling of flat steel used as a material for leaf springs and the like.
【０００２】[0002]
【従来の技術】トラック等に使用される板バネは曲げの
力を受けるため、表面に最大応力が生じる。そのため、
板バネの材料である平鋼の表面に疵が存在すると、そこ
に応力集中を生じ、板バネの疲労寿命を低減させる。2. Description of the Related Art Since a leaf spring used for a truck or the like receives a bending force, maximum stress occurs on the surface. for that reason,
When flaws are present on the surface of flat steel, which is the material of the leaf spring, stress concentration occurs there and the fatigue life of the leaf spring is reduced.
【０００３】平鋼の疵は、熱間圧延時に、何らかの原因
でガイド等に付いた疵、突起等と連続的に接触すること
により生成される掻疵が多い。このような掻疵を検出す
るため、従来は次のような方法が用いられていた。Defects of flat steel often have scratches generated by continuous contact with defects or protrusions attached to guides or the like for some reason during hot rolling. Conventionally, the following method has been used to detect such a flaw.
【０００４】（１）熱間圧延後の平鋼が冷却床で冷却さ
れた後、切断等のためにコンベア上を移動する際に目視
検査を行なう。 （２）平鋼が完全に冷却した後、渦流式の自動探傷機に
より検査を行なう。 （３）同じく完全に冷却し、所定寸法に切断された平鋼
を台上に置き、１枚づつ目視で検査を行なう。 （４）平鋼の冷却前に後端部を切り取り、強制冷却して
目視で検査する。(1) After the flat steel after hot rolling is cooled on a cooling floor, a visual inspection is performed when the flat steel is moved on a conveyor for cutting or the like. (2) After the flat steel is completely cooled, it is inspected by an eddy current type automatic flaw detector. (3) Similarly, the flat steel, which is completely cooled and cut to a predetermined size, is placed on a table and visually inspected one by one. (4) Before cooling the flat steel, the rear end is cut off, forcibly cooled and visually inspected.
【０００５】[0005]
【発明が解決しようとする課題】上記（１）〜（３）の
方法ではいずれも検査が平鋼冷却後となるため、冷却時
間分だけ掻疵の発見が遅れる。掻疵は上記原因で発生す
るため、ガイド等の疵や突起を無くさない限り平鋼には
掻疵が生成され続け、発見が遅れることにより、その時
間分だけ不良品が発生し続けるという問題がある。ま
た、（４）の方法では、製品となる平鋼の全数、全面を
検査することができない。In any of the above methods (1) to (3), the inspection is carried out after the flat steel has been cooled, so that the detection of scratches is delayed by the cooling time. Since scratches occur due to the above causes, scratches will continue to be generated on flat steel unless defects or protrusions such as guides are eliminated, and the delay in discovery causes the problem that defective products continue to occur for that amount of time. is there. Further, with the method (4), it is not possible to inspect all or all of the flat steels to be products.
【０００６】このように、従来の方法では能率の良い検
査を行なおうとすると限定された疵検出しか行なうこと
ができず、確実な検査を行なおうとしても、平鋼冷却後
では多数の不良品が発生した後になるという問題があっ
た。このような問題は、平鋼の熱間圧延の最中にオンラ
インで確実な疵の検出を行なうことができれば解決する
が、従来、熱間圧延材の表面疵検査をオンラインで行な
おうとする試みは、スラブについて行なわれたのみであ
る。しかし、スラブは製品鋼材ではなく素材鋼材である
ため、検出目的は表面疵のような小さい疵ではなく、後
の圧延工程で問題となるような割れ等の大きな欠陥であ
り、また、圧延時の鋼材の移動速度も低い（0.5ｍ／sec
程度）。これに対し、本発明が目的とする製品鋼材であ
る平鋼は仕上圧延速度が数ｍ／secと高速である上、製
品鋼材の表面がそのままバネ等の加工品の表面となるた
め、要求される疵検出のレベルも比較にならない程高
い。As described above, according to the conventional method, if an attempt is made to perform an efficient inspection, only a limited number of flaws can be detected. Even if an attempt is made to perform a reliable inspection, a large number of defects cannot be obtained after cooling the flat steel. There was a problem that it would be after a good product was generated. Such a problem will be solved if reliable flaw detection can be performed online during hot rolling of flat steel, but conventionally, it has been attempted to perform surface flaw inspection of hot rolled material online. Was only done for slabs. However, since the slab is a material steel rather than a product steel, the detection purpose is not a small flaw such as a surface flaw, but a large defect such as a crack that causes a problem in the subsequent rolling process. The moving speed of steel material is also low (0.5m / sec
degree). On the other hand, flat steel, which is a product steel product targeted by the present invention, has a high finishing rolling speed of several m / sec, and the surface of the product steel product directly becomes the surface of a processed product such as a spring. The level of flaw detection is so high that it cannot be compared.
【０００７】本発明はこのような課題を解決するために
成されたものであり、その目的とするところは、熱間圧
延される平鋼の表面疵をオンラインで検出することがで
きる自動検査装置を提供することにある。The present invention has been made to solve such a problem, and an object thereof is to provide an automatic inspection device capable of online detecting surface defects of flat steel to be hot rolled. To provide.
【０００８】[0008]
【課題を解決するための手段、作用及び効果】上記課題
を解決するために成された本発明は、熱間で圧延された
平鋼が長手方向に移動する移動路に配置する平鋼熱間探
傷装置であって、 a)所定の入射角で平鋼の表面に光を照射する光源と、 b)所定の角度づつずらして配置され、各々が平鋼の全幅
からの光を検出することのできる少なくとも１個のライ
ンセンサと、 c)全ラインセンサからの受光信号の中で所定レベル以上
の輝度の部分を疵として検出する信号処理手段と、を備
えることを特徴とするものである。Means for Solving the Problems, Actions and Effects The present invention, which has been made to solve the above-mentioned problems, provides a flat steel hot bar which is arranged in a moving path in which a hot rolled flat steel bar moves in the longitudinal direction. A flaw detection device, comprising: a) a light source that irradiates the surface of flat steel at a predetermined incident angle, and b) staggered by a predetermined angle, each detecting light from the entire width of the flat steel. It is characterized by comprising at least one line sensor which can be provided, and c) signal processing means for detecting a portion having a luminance of a predetermined level or higher in the received light signals from all the line sensors as a flaw.
【０００９】図１１に示すように、掻疵１２の斜面９４
は平鋼１１の平面部（健全部）９５に対して傾斜してい
るため、光源に対する反射光９３の戻り角は疵部と健全
部とで異なる。このため、疵斜面９４からの反射光９３
の方向にラインセンサを配置すると、健全部９５の反射
光は入射せず、掻疵１２の斜面９４からの反射光９３の
みを検出することができる。従って、平鋼１１の全幅を
検出することのできるラインセンサを設けておくことに
より、疵斜面９４の法線９２が丁度光源とラインセンサ
とを２分する位置にある場合には、疵斜面９４により反
射された光９３がラインセンサに入射し、ラインセンサ
で検出される信号中の疵の部分で輝度のピークが現われ
る。ただ、疵斜面９４は鏡面ではないため、このような
角度関係が多少ずれても疵斜面９４により反射された光
９３はラインセンサに入射して検出される。従って、複
数のラインセンサをそのような検出許容角度づつずらし
て配置しておくことにより、疵斜面９４の角度αkがど
のような値であっても、その斜面９４で反射された光９
３はいずれかのラインセンサに入射する。従って、全ラ
インセンサから送出される検出信号の中から、信号処理
手段において所定レベル以上の輝度の部分を検出するこ
とにより、疵が検出される。As shown in FIG. 11, the slope 94 of the scratch 12 is shown.
Is inclined with respect to the flat surface portion (health portion) 95 of the flat steel 11, the return angle of the reflected light 93 with respect to the light source differs between the flaw portion and the sound portion. Therefore, the reflected light 93 from the flaw slope 94
When the line sensor is arranged in the direction of, the reflected light of the sound portion 95 does not enter, and only the reflected light 93 from the slope 94 of the scratch 12 can be detected. Therefore, by providing a line sensor capable of detecting the entire width of the flat steel plate 11, when the normal line 92 of the flaw slope 94 is located at a position that exactly bisects the light source and the line sensor, the flaw slope 94 The light 93 reflected by is incident on the line sensor, and a peak of brightness appears at a flaw portion in the signal detected by the line sensor. However, since the flaw sloped surface 94 is not a mirror surface, the light 93 reflected by the flaw sloped surface 94 enters the line sensor and is detected even if such an angular relationship is slightly shifted. Therefore, by arranging a plurality of line sensors so as to be shifted by such a detection permissible angle, the light 9 reflected by the inclined surface 94 is irrespective of the value of the angle αk of the defective inclined surface 94.
3 is incident on any of the line sensors. Therefore, the flaw is detected by detecting the portion having the brightness equal to or higher than the predetermined level in the signal processing means from the detection signals transmitted from all the line sensors.
【００１０】なお、ラインセンサは、平鋼１１の長手方
向中心線から表面９５に垂直に立てた面に関して光源と
同じ側に配置することが望ましい。これにより、平鋼１
１の表面９５からの反射光がラインセンサに入射するこ
とを完全に防止することができるためである。It is desirable that the line sensor is arranged on the same side as the light source with respect to a plane which stands perpendicular to the surface 95 from the longitudinal center line of the flat steel 11. As a result, flat steel 1
This is because it is possible to completely prevent reflected light from the first surface 95 from entering the line sensor.
【００１１】また、各ラインセンサの前には赤外線カッ
トフィルタを設けることが望ましい。Further, it is desirable to provide an infrared cut filter in front of each line sensor.
【００１２】これは、本探傷装置が、熱間圧延された直
後の平鋼を扱うものであるため平鋼から強い赤外線が放
出されており、これがラインセンサの正常な光検出動作
を妨げる可能性があるためである。This is because the flaw detection device handles flat steel immediately after hot rolling, and strong infrared rays are emitted from the flat steel, which may hinder the normal light detection operation of the line sensor. Because there is.
【００１３】なお、赤外線カットフィルタを使用する代
わりに、光源として７００ｎｍ以下の波長の光を放出す
るレーザを使用し、各ラインセンサの前に該波長に透過
ウィンドウを有する干渉フィルタを設けるようにしても
よい。Instead of using the infrared cut filter, a laser emitting a light having a wavelength of 700 nm or less is used as a light source, and an interference filter having a transmission window at the wavelength is provided in front of each line sensor. Good.
【００１４】本探傷装置により検査が行なわれる平鋼の
温度は最高でも９００℃程度であるため、その放射光の
強度は７００ｎｍよりも短波長側では充分低い。従っ
て、その領域の光を照射し、その波長に透過ウィンドウ
を有する干渉フィルタを用いることにより、平鋼の放射
光に妨げられない正確な疵検出を行なうことができるよ
うになる。Since the temperature of the flat steel to be inspected by this flaw detector is about 900 ° C. at the maximum, the intensity of the emitted light is sufficiently low on the short wavelength side of 700 nm. Therefore, by irradiating the light in that region and using an interference filter having a transmission window at that wavelength, it becomes possible to perform accurate flaw detection that is not obstructed by the radiation of flat steel.
【００１５】次に、各ラインセンサの前に、ラインセン
サの１露光時間よりも短い時間のみ光を透過させる露光
時間制限手段を設けることが望ましい。Next, in front of each line sensor, it is desirable to provide an exposure time limiting means for transmitting light for a time shorter than one exposure time of the line sensor.
【００１６】上述の通り、平鋼の圧延ラインにおける移
動速度は数ｍ／secと非常に速く、また、同程度の速度
で横ブレも生じている。一方、ラインセンサは所定の露
光時間だけ受光して光電変換により電荷を溜め、その
後、溜まった電荷を信号として取り出すものであるが、
この１露光時間は通常のラインセンサの場合、数msec程
度である。平鋼が上記のように数ｍ／secで移動する
と、１露光時間内でも平鋼は数mm移動する。１露光時間
内にこのような大きな横ブレが生じると、疵の斜面から
の反射による輝度のピークが低くなり、疵を検出できな
くなる虞がある。そこで、露光時間制限手段を設けて１
露光時間を短くすることによりブレを小さくし、ピーク
を鋭くすることにより疵検出を可能にする。As described above, the moving speed of the flat steel rolling line is very fast at several m / sec, and lateral blurring occurs at the same speed. On the other hand, the line sensor receives light for a predetermined exposure time, accumulates charges by photoelectric conversion, and then takes out the accumulated charges as a signal.
This one exposure time is about several msec in the case of a normal line sensor. When the flat steel moves at several m / sec as described above, the flat steel moves by several mm even within one exposure time. If such a large lateral blur occurs within one exposure time, the peak of the luminance due to the reflection from the slope of the flaw becomes low, and the flaw may not be detected. Therefore, the exposure time limiting means is provided to
Blurring is reduced by shortening the exposure time, and flaws can be detected by sharpening the peaks.
【００１７】なお、上記光源及び複数のラインセンサは
上記移動路の上下に設けることが望ましい。The light source and the plurality of line sensors are preferably provided above and below the moving path.
【００１８】これにより、平鋼の両面を同時に検査する
ことができる。もちろん、平鋼を移動の途中で裏返し、
同じ移動路を再度通過させることにより、１セットのみ
で両面の検査を行なうことも可能である。Thus, both sides of the flat steel can be inspected at the same time. Of course, turning the flat steel inside out while moving,
It is also possible to inspect both surfaces with only one set by passing the same moving path again.
【００１９】[0019]
【実施例】本発明の一実施例である平鋼熱間探傷装置を
説明する。本実施例の平鋼熱間探傷装置は図２に示すよ
うに、熱間圧延直後の平鋼が走行する移動路２１の上方
に配置された１台の光源２２及び３台のラインセンサ２
３ａ、２３ｂ、２３ｃと疵判定回路２５から成る。光源
２２及び３台のラインセンサ２３ａ、２３ｂ、２３ｃ
は、移動路２１の中心に立てた垂直面１９に関して同一
の側（図２では右側）に配置され、本実施例の場合、そ
れらの水平面からの角度は、光源２２が８０°、３台の
ラインセンサ２３ａ、２３ｂ、２３ｃがそれぞれ７０
°、５０°、３０°となっている。これらの角度が選ば
れた理由については後述する。各ラインセンサ２３ａ、
２３ｂ、２３ｃからの信号は、疵判定回路２５に送られ
る。疵判定回路２５は各ラインセンサ２３ａ、２３ｂ、
２３ｃからの信号に基づき、後述の画像処理を行なって
疵を検出する。EXAMPLE A flat steel hot flaw detector, which is an example of the present invention, will be described. As shown in FIG. 2, the flat steel hot flaw detector according to the present embodiment has one light source 22 and three line sensors 2 arranged above a moving path 21 on which flat steel immediately after hot rolling travels.
It comprises 3a, 23b and 23c and a defect determination circuit 25. Light source 22 and three line sensors 23a, 23b, 23c
Are arranged on the same side (the right side in FIG. 2) with respect to the vertical plane 19 standing upright in the center of the moving path 21, and in the case of the present embodiment, the angles from the horizontal plane are 80 ° for the light sources 22 and 3 units for the three units. The line sensors 23a, 23b, 23c are each 70
The angles are 50, 30 and 30 degrees. The reason why these angles are selected will be described later. Each line sensor 23a,
The signals from 23b and 23c are sent to the flaw determination circuit 25. The defect determination circuit 25 includes line sensors 23a, 23b,
Based on the signal from 23c, the image processing described later is performed to detect the flaw.
【００２０】検査対象である平鋼１１は図１に示すよう
に、上下に平面部、両端に円弧部を有する長尺鋼であ
り、本実施例の探傷装置が検出しようとする疵は平面部
において長手方向に延びる掻疵１２である。一般的に、
掻疵１２は図１（ｂ）に示すように傾斜した左右斜面を
有する。このような掻疵１２を有する多数の平鋼につい
て、疵部分の断面を顕微鏡で観察した結果によると、こ
の疵の斜面の角度（図１１のαk）はほぼ１０〜４０°
の範囲内にあることが判明した。As shown in FIG. 1, the flat steel 11 to be inspected is a long steel having a flat portion on the upper and lower sides and arc portions on both ends, and the flaw to be detected by the flaw detection apparatus of this embodiment is the flat portion. Is a scratch 12 extending in the longitudinal direction. Typically,
The scratch 12 has an inclined right and left slope as shown in FIG. According to the result of observing the cross section of the flaw portion with a microscope for a large number of flat steels having such flaws 12, the angle of the slope of this flaw (αk in FIG. 11) is approximately 10 to 40 °.
It was found to be within the range.
【００２１】しかし、この斜面の表面が光を鏡面反射す
るものであれば、入射光の入射角（光源と疵斜面の垂線
との間の角度）と反射光の出射角（疵斜面の垂線とライ
ンセンサとの間の角度）とが同じでないと、ラインセン
サは疵斜面での反射光を受けることはできない。しか
し、鋼材の表面はそのような鏡面ではないため、入射光
は平鋼の表面（疵斜面は平鋼の表面と同程度の反射特性
を有するものと考えられる）で乱反射をし、主反射角を
中心に或る程度の角度は広がるため、その広がりの範囲
内にラインセンサを配置すれば、疵斜面による反射光を
検出することができる。この平鋼表面での反射による反
射光の広がりの程度を調べるため、次のような実験を行
なった。However, if the surface of the sloped surface reflects light specularly, the incident angle of the incident light (the angle between the light source and the normal of the defective slope) and the outgoing angle of the reflected light (the perpendicular of the defective slope) The angle between the line sensor and the line sensor is not the same, and the line sensor cannot receive the reflected light on the flaw slope. However, since the surface of the steel material is not such a mirror surface, the incident light is diffusely reflected on the surface of the flat steel (the defective slope is considered to have the same reflective characteristics as the surface of the flat steel), and the main reflection angle Since a certain angle spreads around the center, if the line sensor is arranged within the range of the spread, it is possible to detect the light reflected by the flaw slope. The following experiment was conducted to examine the extent of the spread of the reflected light due to the reflection on the flat steel surface.
【００２２】図９に示すように、光源８１を平鋼１１の
表面に対して９０°、１２０°、１３５°、１５０°の
４種の角度の位置に置き、光源８１のこれら各位置にお
いて、ラインセンサ８２を主反射角を中心に左右４０°
づつ移動させ、検出強度を測定した。その結果は図１０
に示す通りであり、主反射角を中心に±１０°の範囲内
では充分な強度の反射光を検出できることが分かった。As shown in FIG. 9, the light source 81 is placed at positions of four angles of 90 °, 120 °, 135 °, and 150 ° with respect to the surface of the flat steel 11, and at each of these positions of the light source 81, The line sensor 82 is 40 ° left and right around the main reflection angle.
It was moved one by one and the detection intensity was measured. The result is shown in Figure 10.
It was found that reflected light with sufficient intensity can be detected within a range of ± 10 ° around the main reflection angle.
【００２３】この実験の結果より、複数個のラインセン
サを２０°づつずらして配置することにより、反射光を
漏れなく検出することができることがわかる。上述の通
り、疵斜面の傾斜角は平鋼表面に対して１０〜４０°の
範囲内にあることから、これらの斜面傾斜角を有する疵
を漏れなくラインセンサで検出するためには、図１２に
示す通り、ラインセンサを３個設ければ十分である。な
お、光源の位置を固定した場合、斜面の角度がθだけ変
化すると、平面から測定した反射角は２×θだけ変化す
ることに注意されたい。図２の配置はこの結果に基づき
決定されたものである。なお、光学的には光源とライン
センサを入れ替えても同じであるため、図８に示すよう
に３台の光源２８ａ、２８ｂ、２８ｃと１台のラインセ
ンサ２７で探傷装置を構成することもできる。なお、光
源とラインセンサを入れ替えて使用する場合は、掻疵が
ない所の散乱光が光源の数の分だけ増加するので、疵判
定回路２５における画像処理の際に注意が必要である。From the results of this experiment, it is understood that the reflected light can be detected without leakage by arranging the plurality of line sensors while shifting them by 20 °. As described above, since the inclination angle of the flaw slope is within the range of 10 to 40 ° with respect to the flat steel surface, in order to detect flaws having these slope inclination angles with the line sensor without leakage, FIG. It is enough to provide three line sensors as shown in FIG. Note that if the position of the light source is fixed and the angle of the slope changes by θ, the reflection angle measured from the plane changes by 2 × θ. The arrangement of FIG. 2 is determined based on this result. Note that the optical source and the line sensor are optically the same, and therefore, as shown in FIG. 8, the three light sources 28a, 28b, and 28c and the one line sensor 27 may constitute a flaw detector. . Note that when the light source and the line sensor are used interchangeably, the scattered light in a place where there is no scratch increases by the number of light sources, and therefore care must be taken in the image processing in the flaw determination circuit 25.
【００２４】次に、平鋼からの放射赤外線対策について
説明する。平鋼からの強力な赤外線をカットする第１の
方法は、ラインセンサ２３ａ、２３ｂ、２３ｃ（又は２
７）に赤外線カットフィルタを設けることである。この
場合に使用する赤外線カットフィルタの必要特性は次の
通りである。通常、平鋼の圧延終了温度は９００℃程度
であるが、図５（ａ）に示すように、９００℃の黒体の
放射エネルギは、約７００nmを境に、それよりも長波長
側で非常に強い。従って、本実施例の探傷装置で用いる
赤外線カットフィルタとしては、約７００ｎｍ以上の波
長の可視・赤外線を有効に遮断する、図５（ａ）に示す
ような透過特性を有するものを使用することが望まし
い。これにより、例えば光源としてハロゲンランプを用
いた場合でも、平鋼からの赤外線に妨害されることな
く、掻疵からの反射光を確実に検出することができる。Next, a measure for radiating infrared rays from flat steel will be described. The first method for cutting the strong infrared rays from the flat steel is the line sensors 23a, 23b, 23c (or 2).
7) is to provide an infrared cut filter. The necessary characteristics of the infrared cut filter used in this case are as follows. Normally, the rolling end temperature of flat steel is about 900 ° C, but as shown in Fig. 5 (a), the radiant energy of a blackbody at 900 ° C is extremely high on the wavelength side longer than about 700 nm. Strong against. Therefore, as the infrared cut filter used in the flaw detection apparatus of the present embodiment, it is possible to use an infrared cut filter having a transmission characteristic as shown in FIG. 5A, which effectively blocks visible / infrared rays having a wavelength of about 700 nm or more. desirable. Accordingly, even when a halogen lamp is used as a light source, for example, the reflected light from the scratch can be reliably detected without being blocked by the infrared rays from the flat steel.
【００２５】平鋼からの赤外線による妨害を防止するも
う一つの方法は、光源として７００ｎｍ以下の波長を有
するレーザを使用し、ラインセンサの前にその波長に透
過ウィンドウを有する干渉フィルタを使用することであ
る。そのような光源の一例としては、Ｈｅ−Ｎｅ（ヘリ
ウム−ネオン）レーザを挙げることができ、この場合、
図５（ｂ）に示すように、光源の波長は６３３ｎｍとな
り、平鋼の温度が９００℃以下の場合には、平鋼からの
赤外線に埋没することなく、疵からの反射信号を確実に
検出することができる。Another way to prevent infrared interference from flat steel is to use a laser with a wavelength below 700 nm as the light source and an interference filter with a transmission window at that wavelength in front of the line sensor. Is. An example of such a light source is a He-Ne (helium-neon) laser, in which case
As shown in FIG. 5B, the wavelength of the light source is 633 nm, and when the flat steel temperature is 900 ° C. or less, the reflected signal from the flaw is reliably detected without being buried in the infrared light from the flat steel. can do.
【００２６】次に、ブレ対策について説明する。通常の
ラインセンサ２３（又は２７）の露光時間（すなわち、
ラインセンサを構成する各光電変換素子が電荷を蓄積す
る時間）ｔ1は約２msec程度である（図４）。しかし、
このように長い露光時間では、高速で走行し、しかも横
ブレする平鋼は数mmも移動し、疵斜面による反射光のピ
ークが低くなって疵検出が困難となる。そこで、本実施
例の探傷装置では図３に示すような回転スリット板３１
をラインセンサ２３の前に設け、ラインセンサ２３の露
光タイミングと同期してモータ３５を高速で回転させる
ことにより、図４に示すように、１露光時間ｔ1内でも
更に短い時間ｔ2の間のみ光がスリット３２を通過し、
ラインセンサ２３に入射するようにした。なお、図３に
おいて３３及び３４は同期をとるためのタイミングノッ
チ及びセンサである。Next, a countermeasure against blurring will be described. The exposure time of the normal line sensor 23 (or 27) (that is,
The time t1 during which each photoelectric conversion element forming the line sensor accumulates charges is about 2 msec (FIG. 4). But,
In such a long exposure time, the flat steel that travels at high speed and moves laterally moves several mm, and the peak of the reflected light due to the flaw slope becomes low, which makes it difficult to detect flaws. Therefore, in the flaw detector of the present embodiment, the rotary slit plate 31 as shown in FIG.
Is provided in front of the line sensor 23, and the motor 35 is rotated at a high speed in synchronization with the exposure timing of the line sensor 23, so that the light is emitted only during a shorter exposure time t2 within one exposure time t1, as shown in FIG. Passes through the slit 32,
The light was made incident on the line sensor 23. In FIG. 3, reference numerals 33 and 34 are timing notches and sensors for achieving synchronization.
【００２７】次に、平鋼１１のコバ１３からの反射光に
対する対策について説明する。図１（ａ）に示すよう
に、平鋼１１の平面から円弧状の斜面に移行する部分
（これをコバ１３と呼ぶ）では表面の角度は０°から９
０°まで連続的に移行する。従って、全てのラインセン
サ２３ａ、２３ｂ、２３ｃにおいてコバ１３による反射
光のピークが現われ、何等の対策をとらないと、疵判定
回路２５においてこの反射光ピークが疵斜面からの反射
光ピークと誤認されてしまう。そこで本実施例の探傷装
置では、検出信号中でピークが所定の閾値以上である箇
所を単純に疵と判定する疵判定回路２５の前に、図６に
示すようなコバ反射ピーク除去回路４１を設け、ライン
センサ２３の信号からコバ１３反射光によるピークを除
外するようにしている。この回路４１の動作は次の通り
である。ラインセンサ２３からの検出信号（図７）は
まずコンパレータ４３に入力され、ここで基準電圧発生
器４２から入力される基準電圧の値と比較される。基準
電圧発生器４２が生成する基準電圧は、平鋼部分をそれ
以外の背景部分と区別する程度の電圧としておく。これ
により、コンパレータ４３の出力電圧は図７に示すよ
うに平鋼の部分でＨigh、背景の部分でＬowとなる２値
信号となる。コンパレータ４３の出力信号はワンショ
ットパルス発生器４４に入力される。ワンショットパル
ス発生器４４は、入力信号の立ち上がりにおいてのみ
短いパルスを生成する回路である。なお、コバ１３によ
る反射光のピークの位置は平鋼１１の板厚によって変化
するため、ワンショットパルス発生器４４により発生さ
せるパルスの幅は、平鋼１１の厚さに応じた適切な値と
なるようにする。ワンショットパルス発生器４４の出力
信号はＮＯＴゲート４６により反転され、反転ワンシ
ョットパルス信号がアナログスイッチ４５に送られ
る。アナログスイッチ４５にはラインセンサ２３からの
信号も入力され、ここにおいて反転ワンショットパル
ス信号により、コバ１３からのピーク（ラインセンサ
２３の走査方向に応じて、このピークは必ず平鋼部分の
最初又は最後に現われる）が除去される。こうして、疵
判定回路２５へはコバ１３による反射光ピークが除去さ
れた検出信号が送られるため、疵判定回路２５では正
しい疵判定が行なわれる。Next, a countermeasure against the reflected light from the edge 13 of the flat steel 11 will be described. As shown in FIG. 1 (a), the angle of the surface is 0 ° to 9 ° in the portion (this is called edge 13) that transitions from the flat surface of the flat steel 11 to the arc-shaped slope.
Transition to 0 ° continuously. Therefore, the peak of the reflected light by the edge 13 appears in all the line sensors 23a, 23b, and 23c, and if no measures are taken, the flaw determination circuit 25 erroneously recognizes this reflected light peak as the reflected light peak from the flaw slope. Will end up. Therefore, in the flaw detection apparatus of the present embodiment, an edge reflection peak removal circuit 41 as shown in FIG. 6 is provided before the flaw determination circuit 25 that simply determines a portion where the peak is equal to or higher than a predetermined threshold in the detection signal as a flaw. The peak due to the reflected light from the edge 13 is excluded from the signal of the line sensor 23. The operation of this circuit 41 is as follows. The detection signal (FIG. 7) from the line sensor 23 is first input to the comparator 43, where it is compared with the value of the reference voltage input from the reference voltage generator 42. The reference voltage generated by the reference voltage generator 42 is set to a voltage that distinguishes the flat steel portion from the other background portions. As a result, the output voltage of the comparator 43 becomes a binary signal which becomes High in the flat steel portion and Low in the background portion as shown in FIG. The output signal of the comparator 43 is input to the one-shot pulse generator 44. The one-shot pulse generator 44 is a circuit that generates a short pulse only at the rising edge of the input signal. Since the position of the peak of the reflected light by the edge 13 changes depending on the plate thickness of the flat steel 11, the width of the pulse generated by the one-shot pulse generator 44 is an appropriate value according to the thickness of the flat steel 11. To be The output signal of the one-shot pulse generator 44 is inverted by the NOT gate 46, and the inverted one-shot pulse signal is sent to the analog switch 45. A signal from the line sensor 23 is also input to the analog switch 45. Here, the inverted one-shot pulse signal causes a peak from the edge 13 (this peak is always the beginning or the flat steel portion depending on the scanning direction of the line sensor 23). Which appears last) is removed. In this way, since the detection signal from which the reflected light peak due to the edge 13 is removed is sent to the defect determination circuit 25, the defect determination circuit 25 makes a correct defect determination.
【図１】 本発明の疵検出対象である平鋼の斜視図
（ａ）と掻疵の拡大断面図（ｂ）。FIG. 1 is a perspective view (a) of a flat steel which is an object of flaw detection according to the present invention and an enlarged sectional view (b) of a flaw.
【図２】 本発明の一実施例である平鋼熱間探傷装置の
概略構成図。FIG. 2 is a schematic configuration diagram of a flat steel hot flaw detector that is an embodiment of the present invention.
【図３】 ラインセンサの前に配置する露光時間制限手
段である回転スリット機構の斜視図。FIG. 3 is a perspective view of a rotary slit mechanism that is an exposure time limiting unit arranged in front of a line sensor.
【図４】 回転スリット機構の露光時間制限動作を示す
タイミングチャート。FIG. 4 is a timing chart showing an exposure time limiting operation of the rotary slit mechanism.
【図５】 赤外線カットフィルタの作用を説明するグラ
フ（ａ）及びＨｅ−Ｎｅレーザ及び干渉フィルタの作用
を説明するグラフ（ｂ）。FIG. 5 is a graph (a) explaining the operation of the infrared cut filter and a graph (b) explaining the operation of the He—Ne laser and the interference filter.
【図６】 コバ反射ピーク除去回路の構成を示すブロッ
ク図。FIG. 6 is a block diagram showing the configuration of an edge reflection peak removal circuit.
【図７】 図６の回路の動作を説明するための信号変化
図。FIG. 7 is a signal change diagram for explaining the operation of the circuit of FIG.
【図８】 本発明の別の実施例を示す概略構成図。FIG. 8 is a schematic configuration diagram showing another embodiment of the present invention.
【図９】 平鋼表面の反射状況を調査するための実験の
方法を示す概略構成図。FIG. 9 is a schematic configuration diagram showing an experimental method for investigating the reflection state of the flat steel surface.
【図１０】 上記実験の結果を示すグラフ。FIG. 10 is a graph showing the results of the above experiment.
【図１１】 疵斜面における反射の様子を示す説明図。FIG. 11 is an explanatory diagram showing a state of reflection on a flaw slope.
【図１２】 いずれかのラインセンサで１０°〜４０°
の角度を持つ疵斜面からの反射光を検出するためのライ
ンセンサの配置表。FIG. 12: 10 ° to 40 ° with either line sensor
Arrangement table of the line sensor for detecting the reflected light from the flaw slope with the angle of.
１１…平鋼 １２…掻疵 １３…コバ ２１…移動路 ２２…光源 ２３…ラインセンサ ３１…回転スリット板 ４１…コバ反射ピーク除去回路 ４２…基準電圧発生器 ４３…コンパレータ ４４…ワンショットパルス発生器 ４５…アナログスイッチ ４６…ＮＯＴゲート ８１…光源 ８２…ラインセンサ ９１…入射光 ９２…疵斜面の法線 ９３…反射光 ９４…疵斜面 11 ... Flat steel 12 ... Scratch 13 ... Edge 21 ... Moving path 22 ... Light source 23 ... Line sensor 31 ... Rotating slit plate 41 ... Edge reflection peak removal circuit 42 ... Reference voltage generator 43 ... Comparator 44 ... One shot pulse generator 45 ... Analog switch 46 ... NOT gate 81 ... Light source 82 ... Line sensor 91 ... Incident light 92 ... Defect slope normal 93 ... Reflected light 94 ... Defect slope
Claims (5)
する移動路に配置する平鋼熱間探傷装置であって、 a)所定の入射角で平鋼の表面に光を照射する光源と、 b)所定の角度づつずらして配置され、各々が平鋼の全幅
からの光を検出することのできる少なくとも１個のライ
ンセンサと、 c)全ラインセンサからの受光信号の中で所定レベル以上
の輝度の部分を疵として検出する信号処理手段と、 を備えることを特徴とする平鋼熱間探傷装置。1. A flat steel hot flaw detector, which is arranged in a moving path in which a hot rolled flat steel moves in a longitudinal direction, comprising: a) irradiating light on the surface of the flat steel at a predetermined incident angle. A light source, b) at least one line sensor that is arranged at a predetermined angle, each of which is capable of detecting light from the entire width of the flat steel, and c) a predetermined light receiving signal from all line sensors. A flat steel hot flaw detector, comprising: a signal processing unit that detects a portion having a luminance equal to or higher than a level as a flaw.
ルタを設けたことを特徴とする請求項１記載の平鋼熱間
探傷装置。2. The flat steel hot flaw detector according to claim 1, wherein an infrared cut filter is provided in front of each line sensor.
放出するレーザを使用し、各ラインセンサの前に該波長
に透過ウィンドウを有する干渉フィルタを設けたことを
特徴とする請求項１記載の平鋼熱間探傷装置。3. The flat panel display according to claim 1, wherein a laser emitting a light having a wavelength of 700 nm or less is used as a light source, and an interference filter having a transmission window at the wavelength is provided in front of each line sensor. Steel hot flaw detector.
１露光時間よりも短い時間のみ光を透過させる露光時間
制限手段を設けたことを特徴とする請求項１〜３のいず
れかに記載の平鋼熱間探傷装置。4. An exposure time limiting means for transmitting light only for a time shorter than one exposure time of the line sensor is provided in front of each line sensor. Flat steel hot flaw detector.
移動路の上下に設けたことを特徴とする請求項１〜４の
いずれかに記載の平鋼熱間探傷装置。5. The flat steel hot flaw detector according to claim 1, wherein the light source and the plurality of line sensors are provided above and below the moving path.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33813594A JPH08178867A (en) | 1994-12-26 | 1994-12-26 | Flat steel hot flaw-detecting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33813594A JPH08178867A (en) | 1994-12-26 | 1994-12-26 | Flat steel hot flaw-detecting device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08178867A true JPH08178867A (en) | 1996-07-12 |
Family
ID=18315246
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33813594A Pending JPH08178867A (en) | 1994-12-26 | 1994-12-26 | Flat steel hot flaw-detecting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08178867A (en) |
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| JP2006329921A (en) * | 2005-05-30 | 2006-12-07 | Kuraray Co Ltd | Method for inspecting optical sheet |
| US7248366B2 (en) | 1999-03-18 | 2007-07-24 | Nkk Corporation | Method for marking defect and device therefor |
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| US7423744B2 (en) | 1999-03-18 | 2008-09-09 | Nkk Corporation | Method for marking defect and device therefor |
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