JP2010117279A - Method and device for detecting surface defect of slab - Google Patents

Method and device for detecting surface defect of slab Download PDF

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JP2010117279A
JP2010117279A JP2008291549A JP2008291549A JP2010117279A JP 2010117279 A JP2010117279 A JP 2010117279A JP 2008291549 A JP2008291549 A JP 2008291549A JP 2008291549 A JP2008291549 A JP 2008291549A JP 2010117279 A JP2010117279 A JP 2010117279A
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slab
unevenness
defect
change rate
laser
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JP5320997B2 (en
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Yoshiharu Kusumoto
義治 楠本
Yasuo Tomura
寧男 戸村
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Jfe Steel Corp
Jfeスチール株式会社
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for detecting a surface defect of a slab for precisely detecting the surface defect such as slag biting produced in the slab. <P>SOLUTION: In the method for detecting the surface defect of the slab by measuring the surface unevenness state of the slab by irradiating the surface of the slab 6 with a laser beam 8, the laser beam reflected from the surface of the slab 6 is detected by a laser beam detector 9 and the sinal output from the laser beam detector 9 is supplied to a surface unevenness state measuring circuit 10. The signal output from the surface unevenness state measuring circuit 10 is supplied to an unevenness change ratio calculating circuit 11 to calculate the unevenness change ratio in the longitudinal direction of the slab and the unevenness change ratio calculated by the unevenness change ratio calculating circuit 11 is compared with a predetermined threshold value by a determination device 12 to determine the region, where the absolute value of the unevenness change ratio becomes the threshold value or above, of the slab, as the surface defect region of the slab. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、スラブの表面欠陥を検出する方法およびその装置に関し、特に、溶鋼を連続鋳造して得られたスラブに手入れを要する表面欠陥が発生しているか否かを検査するときに好適に用いられるスラブの表面欠陥検出方法およびスラブ表面欠陥検出装置に関する。   The present invention relates to a method and an apparatus for detecting a surface defect of a slab, and particularly suitable for inspecting whether or not a surface defect requiring maintenance has occurred in a slab obtained by continuously casting molten steel. The present invention relates to a surface defect detection method and a slab surface defect detection apparatus.
一般に、転炉などで精錬された溶鋼は、図4に示されるように、取鍋(レードル)1を経てダンディッシュ2からモールド(鋳型)3に鋳込まれる。そして、モールド3に鋳込まれた溶鋼はモールド3の下方に配置された多数のピンチローラ4の間を通過する間に表層部のみが凝固した連鋳材となり、さらに不図示の冷却水散水装置から散水される冷却水により冷却されて内部まで固化した後、切断装置5により所定の長さに切断されてスラブ6となる。   Generally, molten steel refined in a converter or the like is cast from a dundish 2 into a mold (mold) 3 through a ladle 1 as shown in FIG. The molten steel cast into the mold 3 becomes a continuous cast material in which only the surface layer portion is solidified while passing between a large number of pinch rollers 4 arranged below the mold 3, and a cooling water sprinkler (not shown) After being cooled by cooling water sprinkled from and solidified to the inside, it is cut into a predetermined length by a cutting device 5 to form a slab 6.
上記のようにして得られるスラブには、種々の表面欠陥が発生する。たとえば、溶鋼の鋳込み時に気泡が巻き込まれると、ブローホールと称される表面欠陥がスラブ表面に発生する。また、溶鋼の凝固時に大きな曲げ応力が加わると、割れと称される表面欠陥がスラブ表面に発生する。さらに、溶鋼の鋳込み時に連続鋳造用パウダーが塊となって巻き込まれると、ノロ噛みと称される表面欠陥がスラブ表面に発生する。これらの表面欠陥はいずれもスラブの表面品質を低下させる要因となるため、溶鋼を連続鋳造して得られたスラブに手入れを要する表面欠陥が生じているか否かを検査する必要がある。   Various surface defects occur in the slab obtained as described above. For example, when bubbles are involved during casting of molten steel, surface defects called blowholes are generated on the slab surface. Further, when a large bending stress is applied during solidification of the molten steel, surface defects called cracks are generated on the slab surface. Furthermore, if the powder for continuous casting is rolled up as a lump when casting molten steel, a surface defect called no-biting occurs on the slab surface. Since these surface defects all cause a reduction in the surface quality of the slab, it is necessary to inspect whether or not a surface defect requiring maintenance has occurred in the slab obtained by continuously casting molten steel.
溶鋼を連続鋳造して得られたスラブに表面欠陥が生じているか否かを検査する方法としては、スラブ表面上の所定領域に照明光を双方向から照射する一対の照明装置と、スラブ表面で反射した照明光をスラブ表面に対しほぼ垂直方向に受光してスラブ表面を撮像する撮像装置とを用いて表面欠陥の有無を検査する方法(特許文献1参照)や、スラブの表面凹みをレーザ距離計により計測し、レーザ距離計により計測された表面凹みから割れの有無を検査する方法(特許文献2参照)などが知られている。
特開2004−219358号公報 特開平2−224851号公報
As a method for inspecting whether or not a surface defect has occurred in a slab obtained by continuously casting molten steel, a pair of illumination devices that irradiate illumination light in two directions to a predetermined area on the slab surface, and a slab surface A method of inspecting for the presence or absence of surface defects using an imaging device that receives reflected illumination light in a direction substantially perpendicular to the slab surface and images the slab surface (see Patent Document 1), and the surface dent of the slab is measured by the laser distance. A method of measuring the presence of cracks from a surface dent measured by a meter and using a laser distance meter (see Patent Document 2) is known.
JP 2004-219358 A JP-A-2-224851
しかしながら、特許文献1に開示された方法は、撮像装置で得られたスラブ表面画像の濃淡から表面欠陥の有無を検査しているため、スラブに発生した表面欠陥がブローホールや割れであるのか、それともノロ噛みであるのかを判別することができないという問題点がある。
一方、特許文献2に開示された方法は、レーザ距離計により計測された表面凹みの深さから表面欠陥の有無を検査しているため、特許文献1に開示された方法と同様に、スラブに発生した表面欠陥がブローホールや割れであるのか、それともノロ噛みであるのかを判別することができないという問題点がある。
本発明は上述した事情に鑑みてなされたもので、スラブに発生したノロ噛み等の表面欠陥を精度よく検出することのできるスラブの表面欠陥検出方法およびスラブ表面欠陥検出装置を提供することを目的とする。
However, since the method disclosed in Patent Document 1 is inspecting the presence or absence of surface defects from the density of the slab surface image obtained by the imaging device, whether the surface defects generated in the slab are blowholes or cracks, Or, there is a problem that it cannot be determined whether the bite is bitten.
On the other hand, since the method disclosed in Patent Document 2 inspects the presence or absence of surface defects from the depth of the surface dent measured by the laser distance meter, as in the method disclosed in Patent Document 1, There is a problem in that it is impossible to determine whether the generated surface defect is a blowhole or a crack or a bite.
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a slab surface defect detection method and a slab surface defect detection apparatus capable of accurately detecting surface defects such as slotting generated in a slab. And
上記目的を達成するために、請求項1の発明は、スラブの表面にレーザ光を照射してスラブ表面の凹凸状態を計測することでスラブ表面に発生した表面欠陥を検出する方法であって、前記スラブ表面の凹凸状態からスラブの長手方向における凹凸変化率を算出し、該算出した凹凸変化率の絶対値が予め定めた閾値以上となった部位を表面欠陥と判定することを特徴とするものである。   In order to achieve the above object, the invention of claim 1 is a method of detecting surface defects generated on the slab surface by irradiating the surface of the slab with laser light and measuring the uneven state of the slab surface, The unevenness change rate in the longitudinal direction of the slab is calculated from the unevenness state of the slab surface, and a portion where the absolute value of the calculated unevenness change rate is equal to or greater than a predetermined threshold is determined as a surface defect. It is.
請求項2の発明は、スラブの表面にレーザ光を照射してスラブ表面の凹凸状態を計測することでスラブ表面に発生した表面欠陥を検出するスラブ表面欠陥検出装置であって、前記スラブ表面で反射したレーザ光を受光するレーザ光受光手段と、該レーザ光受光手段で受光したレーザ光を基に前記スラブ表面の凹凸状態を計測する表面凹凸状態計測手段と、該表面凹凸状態計測手段で計測されたスラブ表面の凹凸状態から前記スラブの長手方向における凹凸変化率を算出する凹凸変化率算出手段と、該凹凸変化率算出手段で得られた凹凸変化率の値を予め定めた閾値と比較し、凹凸変化率の絶対値が閾値以上となった場合に表面欠陥と判定する表面欠陥判定手段とを備えたことを特徴とするものである。   The invention of claim 2 is a slab surface defect detection device for detecting surface defects generated on the slab surface by irradiating the surface of the slab with laser light and measuring the uneven state of the slab surface, Laser light receiving means for receiving the reflected laser light, surface uneven state measuring means for measuring the uneven state of the slab surface based on the laser light received by the laser light receiving means, and measurement by the surface uneven state measuring means The unevenness change rate calculating means for calculating the unevenness change rate in the longitudinal direction of the slab from the uneven state of the surface of the slab, and the unevenness change rate value obtained by the unevenness change rate calculating means is compared with a predetermined threshold value. And a surface defect determining means for determining a surface defect when the absolute value of the unevenness change rate is equal to or greater than a threshold value.
請求項1及び請求項2の発明によると、スラブ表面の凹凸状態からスラブの長手方向における凹凸変化率を算出し、算出された凹凸変化率を予め定めた閾値と比較し、凹凸変化率の絶対値が閾値以上となった部位を表面欠陥と判定するため、スラブに発生したノロ噛み等の表面欠陥を精度よく検出することができる。   According to the invention of claim 1 and claim 2, the unevenness change rate in the longitudinal direction of the slab is calculated from the uneven state of the slab surface, the calculated unevenness change rate is compared with a predetermined threshold value, and the absolute unevenness change rate is calculated. Since the part where the value is equal to or greater than the threshold is determined as a surface defect, it is possible to accurately detect a surface defect such as a bite generated in the slab.
以下、図1〜図3を参照して、本発明に係るスラブの表面欠陥検出方法およびスラブ表面欠陥検出装置について説明する。
図1は本発明の一実施形態に係るスラブ表面欠陥検出装置の概略構成を示す図であり、図1に示されるように、本発明の一実施形態に係るスラブ表面欠陥検出装置は、レーザ投光器7a,7b、レーザ光受光手段としてのレーザ受光器9、表面凹凸状態計測手段としての表面凹凸状態計測回路10、凹凸変化率算出手段としての凹凸変化率算出回路11、および表面欠陥判定手段としての判定装置12を備えている。
Hereinafter, a slab surface defect detection method and a slab surface defect detection apparatus according to the present invention will be described with reference to FIGS.
FIG. 1 is a diagram showing a schematic configuration of a slab surface defect detection apparatus according to an embodiment of the present invention. As shown in FIG. 1, the slab surface defect detection apparatus according to an embodiment of the present invention is a laser projector. 7a and 7b, a laser receiver 9 as a laser beam receiving unit, a surface uneven state measuring circuit 10 as a surface uneven state measuring unit, an uneven change rate calculating circuit 11 as an uneven change rate calculating unit, and a surface defect determining unit A determination device 12 is provided.
レーザ投光器7a,7bは検査対象物であるスラブ6の表面に例えば0.1〜0.2mmのビーム幅を有するスリット状のレーザ光8を投光するものであり、スラブ6の幅方向に一定間隔で配列されている。また、レーザ投光器7a,7bはスラブ6からの輻射熱が届かない位置(例えば、スラブ表面から上方に2500mm以上離れた位置)に配置されており、従って、スラブ6の表面にはレーザ投光器7a,7bからのレーザ光8がほぼ真上から投光されるようになっている。なお、レーザ投光器7a,7bからスラブ6の表面に投光されたレーザ光はスラブ6の表面で反射した後、レーザ受光器9に入射するようになっている。   The laser projectors 7 a and 7 b project a slit-shaped laser beam 8 having a beam width of, for example, 0.1 to 0.2 mm onto the surface of the slab 6 that is an inspection object, and are constant in the width direction of the slab 6. Arranged at intervals. The laser projectors 7a and 7b are disposed at a position where the radiant heat from the slab 6 does not reach (for example, a position spaced 2500 mm or more upward from the surface of the slab). The laser beam 8 is projected from almost right above. The laser light projected on the surface of the slab 6 from the laser projectors 7 a and 7 b is reflected on the surface of the slab 6 and then enters the laser receiver 9.
レーザ受光器9はスラブ6の表面で反射したレーザ光を受光するものであり、このレーザ受光器9から出力された信号は、スラブ表面の凹凸変化情報として凹凸状態計測回路10に供給されるようになっている。
表面凹凸状態計測回路10はレーザ受光器9から出力された信号を基にスラブ6の幅方向におけるスラブ表面の凹凸状態をスラブ6の進行方向である長手方向に連続的に計測してスラブ表面全体の凹凸データを取得するものであり、この表面凹凸状態計測回路10から出力された信号は凹凸変化率算出回路11に供給されるようになっている。
The laser receiver 9 receives the laser beam reflected by the surface of the slab 6, and the signal output from the laser receiver 9 is supplied to the unevenness state measuring circuit 10 as unevenness change information on the surface of the slab. It has become.
The surface unevenness state measurement circuit 10 continuously measures the unevenness state of the slab surface in the width direction of the slab 6 in the longitudinal direction that is the traveling direction of the slab 6 based on the signal output from the laser receiver 9 to measure the entire surface of the slab. The data output from the surface unevenness state measurement circuit 10 is supplied to the unevenness change rate calculation circuit 11.
凹凸変化率算出回路11は表面凹凸状態計測回路10により計測した表面凹凸状態のデータを処理してスラブ6の長手方向におけるスラブ表面の凹凸変化率を算出するものであり、この凹凸変化率算出回路11から出力された信号は、スラブ6の表面に発生する表面欠陥情報として判定装置12に供給されるようになっている。
判定装置12は凹凸変化率算出回路11で算出されたスラブ表面の凹凸変化率と予め定めた閾値とを比較して表面欠陥の有無等を判定するものであり、スラブの内部側に凹となる方向の凹凸変化率の絶対値(以下、単に「凹凸変化率の絶対値」と記す。)が閾値以上の場合には「スラブ6の表面にノロ噛みが発生した。」と判定し、凹凸変化率の絶対値が閾値より小さい場合には「スラブ6の表面にノロ噛みが発生していない。」と判定するように構成されている。
The unevenness change rate calculation circuit 11 processes the surface unevenness data measured by the surface unevenness state measurement circuit 10 and calculates the unevenness change rate of the slab surface in the longitudinal direction of the slab 6. This unevenness change rate calculation circuit The signal output from 11 is supplied to the determination device 12 as surface defect information generated on the surface of the slab 6.
The determination device 12 compares the unevenness change rate of the slab surface calculated by the unevenness change rate calculation circuit 11 with a predetermined threshold value to determine the presence or absence of surface defects and the like, and is concave on the inner side of the slab. When the absolute value of the direction unevenness change rate (hereinafter simply referred to as “absolute value of unevenness change rate”) is equal to or greater than the threshold value, it is determined that “no bite has occurred on the surface of the slab 6”, and the unevenness change. When the absolute value of the rate is smaller than the threshold value, it is determined that “no biting has occurred on the surface of the slab 6”.
スラブ6の表面にノロ噛みと称される表面欠陥が発生したときのスラブ表層部の断面を図2に示す。図2に示されるように、ノロ噛みと称される表面欠陥がスラブ6に発生すると、スラブ6の表面凹凸がノロ噛み13の先端部分で急峻に変化することがわかる。
スラブ6の表面にノロ噛みが発生したときの凹凸変化率算出回路11の出力信号波形の一例を図3に示す。図3に示されるように、スラブ6の表面にノロ噛みが発生すると、凹凸変化率算出回路11で算出されるスラブ長手方向の凹凸変化率が大きく変化することがわかる。
FIG. 2 shows a cross section of the surface portion of the slab when a surface defect called no-biting occurs on the surface of the slab 6. As shown in FIG. 2, it can be seen that when a surface defect called no-biting occurs in the slab 6, the surface unevenness of the slab 6 changes sharply at the tip of the no-biting 13.
FIG. 3 shows an example of an output signal waveform of the unevenness change rate calculation circuit 11 when the bite is generated on the surface of the slab 6. As shown in FIG. 3, it can be seen that when the bite occurs on the surface of the slab 6, the unevenness change rate in the longitudinal direction of the slab calculated by the unevenness change rate calculation circuit 11 changes greatly.
したがって、凹凸変化率算出回路11で算出された凹凸変化率の絶対値を予め定めた閾値と比較することで、スラブ6にノロ噛みが発生している場合には凹凸変化率の絶対値が閾値以上となるので、スラブ6に発生した表面欠陥がノロ噛みであるか否かを精度よく検出することができる。
上述した本発明の一実施形態では、レーザ投光器からのレーザ光をスラブの表面にほぼ真上から投光するようにしたが、これに限られるものではなく、レーザ投光器からのレーザ光をスラブの表面に斜め上方から投光するようにしてもよい。ただし、より高い精度で表面欠陥を検出するためには、レーザ投光器からのレーザ光をスラブの表面にほぼ真上から投光することが好ましい。
Therefore, by comparing the absolute value of the unevenness change rate calculated by the unevenness change rate calculating circuit 11 with a predetermined threshold value, the absolute value of the unevenness change rate is the threshold value when the bite is generated in the slab 6. Therefore, it is possible to accurately detect whether or not the surface defect generated in the slab 6 is a bite.
In the above-described embodiment of the present invention, the laser light from the laser projector is projected onto the surface of the slab from directly above, but the present invention is not limited to this, and the laser light from the laser projector is transmitted to the slab. You may make it light-project on the surface from diagonally upward. However, in order to detect a surface defect with higher accuracy, it is preferable to project the laser beam from the laser projector onto the surface of the slab from directly above.
また、上述した本発明の一実施形態では、スラブの幅方向に配列された二つのレーザ投光器からスラブの表面にレーザ光を投光するようにしたが、これに限られるものではなく、スラブの幅寸法に応じてレーザ投光器の個数を適宜設定すればよい。
また、上述した本発明の一実施形態では、スラブの表面で反射したレーザ光を1個のレーザ受光器で受光するようにしたが、これに限られるものではなく、レーザ光受光手段としてのレーザ受光器の個数は複数個であってもよい。
Further, in the above-described embodiment of the present invention, laser light is projected onto the surface of the slab from the two laser projectors arranged in the width direction of the slab. However, the present invention is not limited to this. What is necessary is just to set the number of laser projectors suitably according to a width dimension.
In the above-described embodiment of the present invention, the laser beam reflected by the surface of the slab is received by one laser receiver. However, the present invention is not limited to this. A plurality of light receivers may be provided.
また、スラブの長手方向における凹凸変化率を求める方法としては、上述した本発明の一実施形態のように、スラブの幅方向に長いスリット状のレーザ光をスラブの表面に照射しながらスラブをその長手方向に移動させてスラブの長手方向における凹凸変化率を求めてもよいし、スラブの表面に照射されたスリット状あるいはスポット状のレーザ光をスラブの幅方向や長手方向に走査してスラブの長手方向における凹凸変化率を求めてもよい。   In addition, as a method of obtaining the unevenness change rate in the longitudinal direction of the slab, as in the embodiment of the present invention described above, the slab is irradiated while irradiating the surface of the slab with a slit-like laser beam that is long in the width direction of the slab. It may be moved in the longitudinal direction to obtain the unevenness change rate in the longitudinal direction of the slab, or a slit-like or spot-like laser beam irradiated on the surface of the slab is scanned in the width direction or longitudinal direction of the slab. The unevenness change rate in the longitudinal direction may be obtained.
また、上述した本発明の一実施形態では、レーザ受光器から出力された信号を微分処理してスラブの長手方向における凹凸変化率を取得するようにしたが、これに限られるものではなく、例えば、表面凹凸状態計測回路により計測された二つの計測点の間の傾きからスラブの長手方向における凹凸変化率を取得するようにしてもよい。
上述した本発明の一実施形態では、スラブの上面側における表面欠陥の検出について記載したが、本発明はスラブの下面側における表面欠陥の検出についても同様に適用することができる。さらに、本発明の構成を、スラブの上面側及び下面側に設けることで、スラブの上下面の欠陥の検出が同時に可能となる。
Further, in the above-described embodiment of the present invention, the signal output from the laser receiver is differentiated to obtain the unevenness change rate in the longitudinal direction of the slab. However, the present invention is not limited to this. For example, The unevenness change rate in the longitudinal direction of the slab may be acquired from the inclination between the two measurement points measured by the surface unevenness state measurement circuit.
In the above-described embodiment of the present invention, detection of surface defects on the upper surface side of the slab has been described, but the present invention can be similarly applied to detection of surface defects on the lower surface side of the slab. Furthermore, by providing the configuration of the present invention on the upper surface side and the lower surface side of the slab, it becomes possible to simultaneously detect defects on the upper and lower surfaces of the slab.
本発明の一実施形態に係るスラブ表面欠陥検出装置の概略構成を示す図である。It is a figure which shows schematic structure of the slab surface defect detection apparatus which concerns on one Embodiment of this invention. スラブの表面にノロ噛みと称される表面欠陥が発生したときのスラブ表層部の断面を示す図である。It is a figure which shows the cross section of the slab surface layer part when the surface defect called the biting in the surface of the slab generate | occur | produced. スラブの表面にノロ噛みが発生したときの凹凸変化率算出回路の出力信号波形の一例を示す図である。It is a figure which shows an example of the output signal waveform of the uneven | corrugated change rate calculation circuit when the biting has occurred on the surface of the slab. 溶鋼の連続鋳造設備の一例を模式的に示す図である。It is a figure which shows typically an example of the continuous casting equipment of molten steel.
符号の説明Explanation of symbols
1 取鍋
2 ダンディッシュ
3 モールド(鋳型)
4 ピンチローラ
5 切断装置
6 スラブ
7a,7b レーザ投光器
8 レーザ光
9 レーザ受光器(レーザ光受光手段)
10 表面凹凸状態計測回路(表面凹凸状態計測手段)
11 凹凸変化率算出回路(凹凸変化率算出手段)
12 判定装置(表面欠陥判定手段)
13 ノロ噛み
1 Ladle 2 Dundish 3 Mold
4 Pinch roller 5 Cutting device 6 Slab 7a, 7b Laser projector 8 Laser light 9 Laser receiver (laser light receiving means)
10 Surface unevenness measurement circuit (surface unevenness measurement means)
11 Unevenness change rate calculation circuit (unevenness change rate calculation means)
12 Judgment device (surface defect judgment means)
13 Noro biting

Claims (2)

  1. スラブの表面にレーザ光を照射してスラブ表面の凹凸状態を計測することでスラブ表面に発生した表面欠陥を検出する方法であって、
    前記スラブ表面の凹凸状態からスラブの長手方向における凹凸変化率を算出し、該算出した凹凸変化率の絶対値が予め定めた閾値以上となった部位を表面欠陥と判定することを特徴とするスラブの表面欠陥検出方法。
    A method for detecting surface defects generated on the surface of the slab by irradiating the surface of the slab with laser light and measuring the uneven state of the surface of the slab,
    A slab characterized by calculating a concavo-convex change rate in the longitudinal direction of the slab from the concavo-convex state of the slab surface, and determining a portion where the absolute value of the calculated concavo-convex change rate is equal to or greater than a predetermined threshold as a surface defect. Surface defect detection method.
  2. スラブの表面にレーザ光を照射してスラブ表面の凹凸状態を計測することでスラブ表面に発生した表面欠陥を検出するスラブ表面欠陥検出装置であって、
    前記スラブ表面で反射したレーザ光を受光するレーザ光受光手段と、
    該レーザ光受光手段で受光したレーザ光を基に前記スラブ表面の凹凸状態を計測する表面凹凸状態計測手段と、
    該表面凹凸状態計測手段で計測されたスラブ表面の凹凸状態から前記スラブの長手方向における凹凸変化率を算出する凹凸変化率算出手段と、
    該凹凸変化率算出手段で得られた凹凸変化率の値を予め定めた閾値と比較し、凹凸変化率の絶対値が閾値以上となった場合に表面欠陥と判定する表面欠陥判定手段とを備えたことを特徴とするスラブ表面欠陥検出装置。
    A slab surface defect detection device that detects surface defects generated on the slab surface by irradiating the surface of the slab with laser light and measuring the uneven state of the slab surface,
    Laser light receiving means for receiving the laser light reflected by the slab surface;
    Surface unevenness state measuring means for measuring the unevenness state of the slab surface based on the laser beam received by the laser light receiving means;
    An unevenness change rate calculating means for calculating an unevenness change rate in the longitudinal direction of the slab from the uneven state of the slab surface measured by the surface unevenness state measuring means;
    Comparing the value of the unevenness change rate obtained by the unevenness change rate calculating means with a predetermined threshold value, and comprising surface defect determining means for determining a surface defect when the absolute value of the unevenness change rate is equal to or greater than the threshold value. A slab surface defect detection device characterized by that.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103185720A (en) * 2011-12-29 2013-07-03 宝山钢铁股份有限公司 Casting blank lower surface image detection device and detection method

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59107758A (en) * 1982-12-10 1984-06-22 Kobe Steel Ltd Method and device for detecting slag inclusion in hot flaw detection on surface of continuous casting material
JPS6347642A (en) * 1986-08-14 1988-02-29 Kawasaki Steel Corp Method for discriminating kind of flaw in surface flaw detection
JPH02224851A (en) * 1989-02-25 1990-09-06 Nippon Steel Corp Method for deciding crack in cast strip
JPH03140847A (en) * 1989-10-27 1991-06-14 Kubota Corp Method for detecting shape of flaw part
JPH04148817A (en) * 1990-10-11 1992-05-21 Mitsubishi Kasei Corp Surface inspecting apparatus
JPH0543242B2 (en) * 1986-09-26 1993-07-01 Toyo Tire & Rubber Co
JPH0921761A (en) * 1993-07-14 1997-01-21 Toshiba Corp Surface fault inspecting apparatus
JP2955686B2 (en) * 1990-11-30 1999-10-04 マツダ株式会社 Surface defect inspection equipment
JP2003094156A (en) * 2001-09-20 2003-04-02 Nippon Steel Engineering Osaka Co Ltd System and method for detecting biting of base metal
JP2004130328A (en) * 2002-10-09 2004-04-30 Nippon Steel Corp Detecting and removing method for surface flaw of slab, apparatus therefor, and detecting and removing equipment line
JP2004219358A (en) * 2003-01-17 2004-08-05 Nippon Steel Corp Apparatus for detecting surface flaw in billet

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59107758A (en) * 1982-12-10 1984-06-22 Kobe Steel Ltd Method and device for detecting slag inclusion in hot flaw detection on surface of continuous casting material
JPS6347642A (en) * 1986-08-14 1988-02-29 Kawasaki Steel Corp Method for discriminating kind of flaw in surface flaw detection
JPH0543242B2 (en) * 1986-09-26 1993-07-01 Toyo Tire & Rubber Co
JPH02224851A (en) * 1989-02-25 1990-09-06 Nippon Steel Corp Method for deciding crack in cast strip
JPH03140847A (en) * 1989-10-27 1991-06-14 Kubota Corp Method for detecting shape of flaw part
JPH04148817A (en) * 1990-10-11 1992-05-21 Mitsubishi Kasei Corp Surface inspecting apparatus
JP2955686B2 (en) * 1990-11-30 1999-10-04 マツダ株式会社 Surface defect inspection equipment
JPH0921761A (en) * 1993-07-14 1997-01-21 Toshiba Corp Surface fault inspecting apparatus
JP2003094156A (en) * 2001-09-20 2003-04-02 Nippon Steel Engineering Osaka Co Ltd System and method for detecting biting of base metal
JP2004130328A (en) * 2002-10-09 2004-04-30 Nippon Steel Corp Detecting and removing method for surface flaw of slab, apparatus therefor, and detecting and removing equipment line
JP2004219358A (en) * 2003-01-17 2004-08-05 Nippon Steel Corp Apparatus for detecting surface flaw in billet

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103185720A (en) * 2011-12-29 2013-07-03 宝山钢铁股份有限公司 Casting blank lower surface image detection device and detection method

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