JPH0643097A - Method for measuring alloying degree of galvanized sheet iron - Google Patents

Method for measuring alloying degree of galvanized sheet iron

Info

Publication number
JPH0643097A
JPH0643097A JP19863692A JP19863692A JPH0643097A JP H0643097 A JPH0643097 A JP H0643097A JP 19863692 A JP19863692 A JP 19863692A JP 19863692 A JP19863692 A JP 19863692A JP H0643097 A JPH0643097 A JP H0643097A
Authority
JP
Japan
Prior art keywords
light
steel sheet
alloying
level
detected
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.)
Granted
Application number
JP19863692A
Other languages
Japanese (ja)
Other versions
JP2733416B2 (en
Inventor
Kiyoshi Shimada
田 清 島
Hiroshi Taki
喜 弘 多
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Nippon Steel Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nippon Steel Corp filed Critical Nippon Steel Corp
Priority to JP19863692A priority Critical patent/JP2733416B2/en
Publication of JPH0643097A publication Critical patent/JPH0643097A/en
Application granted granted Critical
Publication of JP2733416B2 publication Critical patent/JP2733416B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Abstract

PURPOSE:To prevent that an error occurs and a measurement cannot be made by the vibration of a steel plate and the fluctuation of a pass line, and to remove the error occurring due to the radiation of a furnace wall. CONSTITUTION:A longitudinal scan mirror 6 and a lateral scan mirror 7 are provided, and a laser beam is scanned in the shape of a plane on a steel plate. The maximum value of a light-reception level detected during the plane scanning is utilized. A period of a laser beam being off is set, a background light level is detected, and a regular reflection light level is found from the maximum value-background light level. An angle divergence of the steel plate is detected from the scan position at the time when the maximum value is detected, and the angle correction is conducted. The moving average value of a plurality of plane scan times is computed, and it is prevented that the alloying unevenness, etc., exert an adverse effect on the measured result. A current corresponding to the background light level is allowed to flow to the input of an amplifier 31, and the saturation of the input level is prevented.

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、亜鉛メッキ鋼板の合金
化度計測方法に関し、例えば合金化炉内において表層部
の合金化が進行中の亜鉛メッキ鋼板の合金化度を計測す
るために利用しうる。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the degree of alloying of a galvanized steel sheet, which is used, for example, to measure the degree of alloying of a galvanized steel sheet in which the alloying of the surface layer is in progress in an alloying furnace. You can.

【0002】[0002]

【従来の技術】亜鉛メッキ鋼板は、耐食性が高く発錆性
が低いという特徴を有しており、その中でも特に合金化
亜鉛メッキ鋼板は、塗装性に優れしかもプレス加工時に
トラブルの発生が少ないので、自動車や家電製品などの
用途に広く用いられている。
2. Description of the Related Art Galvanized steel sheets are characterized by high corrosion resistance and low rust resistance. Among them, alloyed galvanized steel sheets are excellent in coatability and have few troubles during press working. Widely used in applications such as automobiles and home appliances.

【0003】合金化亜鉛メッキ鋼板を製造する場合、一
般的には、まず鋼板を所定温度(例えば460℃)の溶
融亜鉛浴中に通して表面に亜鉛メッキ層を形成し、続い
てそれを合金化炉に入れて500〜600℃程度に加熱
する。この加熱処理によって、拡散が生じ、メッキ層に
鉄と亜鉛の合金が形成される。
In the case of producing an alloyed galvanized steel sheet, generally, the steel sheet is first passed through a hot dip zinc bath at a predetermined temperature (for example, 460 ° C.) to form a galvanized layer on the surface, and then it is alloyed. Put in a chemical furnace and heat to about 500 to 600 ° C. This heat treatment causes diffusion to form an alloy of iron and zinc in the plated layer.

【0004】合金化亜鉛メッキ鋼板を製造する上で重要
なことは、メッキ層の合金化の程度を適正に維持するこ
とである。即ち、合金化不足(生焼けと呼ばれる)の場
合には塗装性が悪化し、合金化が過度に進行すると、プ
レス加工時にパウダリングが生じたり、スポット溶接の
不良が発生し易くなる。一般に、合金化亜鉛メッキ鋼板
の適正な合金化メッキ層は、該層中の鉄分が10%程度
のものと考えられている。
An important factor in producing an alloyed galvanized steel sheet is to maintain a proper degree of alloying of the plated layer. That is, in the case of insufficient alloying (referred to as "burning"), the paintability is deteriorated, and if alloying proceeds excessively, powdering may occur during press working or defective spot welding may easily occur. Generally, a proper alloyed plated layer of an alloyed galvanized steel sheet is considered to have an iron content of about 10%.

【0005】合金化亜鉛メッキ鋼板の表層部の合金化度
は、合金化炉の温度や鋼板の通板速度(即ち合金化炉内
での滞留時間)の調整によって変えることができる。し
かしながら、それらの条件を一定に制御しても、合金化
度は別の要因によって変化してしまう。即ち、亜鉛浴中
の微量元素濃度や、鋼板素材に含まれる微量化学成分に
応じて、合金化の進行度合いは変化するので、合金化炉
の温度や鋼板の通板速度を一定に維持しても、コイル毎
に鋼板表層部の合金化度は変化してしまう。従って、合
金化亜鉛メッキ鋼板の表層部の合金化度を適正に制御す
るためには、合金化度を計測する必要がある。
The degree of alloying of the surface layer portion of the galvannealed steel sheet can be changed by adjusting the temperature of the alloying furnace and the passage speed of the steel sheet (that is, the residence time in the alloying furnace). However, even if those conditions are controlled to be constant, the alloying degree changes due to another factor. That is, the degree of progress of alloying changes depending on the trace element concentration in the zinc bath and the trace chemical components contained in the steel sheet material.Therefore, the temperature of the alloying furnace and the steel sheet passing speed should be kept constant. However, the alloying degree of the surface layer of the steel sheet changes for each coil. Therefore, in order to properly control the alloying degree of the surface layer portion of the galvannealed steel sheet, it is necessary to measure the alloying degree.

【0006】合金化亜鉛メッキ鋼板の表層部の合金化度
を計測する技術としては、従来より、特開昭58−16
061号公報や、特開昭58−210550号公報に開
示されたものが公知である。前者の技術では、可視光線
を鋼板表面に照射し、鋼板からの乱反射光の強度を計測
して合金化度を検出しており、後者の技術では、鋼板に
光を照射し、正反射方向に配置した光検出器で反射光の
強度分布を測定し、光強度分布の半値幅の大きさから合
金化度を検出している。
As a technique for measuring the degree of alloying of the surface layer portion of an alloyed galvanized steel sheet, there has been conventionally used a technique disclosed in JP-A-58-16.
No. 061 and Japanese Patent Laid-Open No. 58-210550 are known. In the former technology, the surface of the steel sheet is irradiated with visible light and the intensity of diffusely reflected light from the steel sheet is measured to detect the degree of alloying.In the latter technology, the steel sheet is irradiated with light and the direction of specular reflection is detected. The intensity distribution of the reflected light is measured by the photodetector arranged, and the degree of alloying is detected from the size of the half width of the light intensity distribution.

【0007】[0007]

【発明が解決しようとする課題】溶融亜鉛浴中を通り表
面に亜鉛メッキ層が形成された鋼板については、合金化
処理が完了するまではその表面に触れることができない
ので、溶融亜鉛浴から出た鋼板は、長い距離(例えば1
00m)を全く支持されることなく、鉛直方向に搬送さ
れ、その間に合金化炉を通る。このため、合金化処理中
の鋼板に、その搬送方向,幅方向,厚み方向等に対し
て、それぞれ振動あるいはパスライン変動が生じるのは
避けられない。
With respect to a steel sheet having a galvanized layer formed on the surface through the molten zinc bath, the surface cannot be touched until the alloying treatment is completed. The steel plate has a long distance (eg 1
00m) is transported in the vertical direction without any support, and passes through an alloying furnace in the meantime. For this reason, it is inevitable that the steel sheet undergoing alloying undergoes vibrations or path line fluctuations in the carrying direction, width direction, thickness direction, and the like.

【0008】振動やパスライン変動が生じている鋼板に
対して、従来技術で合金化度を測定しようとすると、正
確な測定結果が得られない。即ち、乱反射光を検出する
場合には、振動やパスライン変動によって、鋼板に対す
る光の入射角と反射角が変化すると、固定された光検出
器に入射する乱反射光の強度が変化し、検出誤差が生じ
る。また正反射光の分布を検出する場合には、振動やパ
スライン変動によって、鋼板に対する光の入射角と反射
角が変化すると、正反射光の方向が検出器位置を外れる
ので、正反射光の強度分布が検出できず、また鋼板と検
出器との距離変動に伴なって受光レンズの焦点ずれが生
じるので、測定誤差が生じる。
When the alloying degree is measured by the conventional technique with respect to a steel sheet having vibrations or fluctuations in the pass line, an accurate measurement result cannot be obtained. That is, when detecting irregularly reflected light, if the incident angle and the reflection angle of the light on the steel plate change due to vibration or path line variation, the intensity of the irregularly reflected light incident on the fixed photodetector changes, resulting in a detection error. Occurs. When detecting the distribution of specular reflection light, if the incident angle and reflection angle of light on the steel plate change due to vibration or path line fluctuation, the direction of specular reflection light deviates from the detector position. The intensity distribution cannot be detected, and the focus shift of the light-receiving lens occurs due to the distance variation between the steel plate and the detector, resulting in a measurement error.

【0009】また合金化炉においては、炉壁から発光が
生じるので、鋼板からの反射光の他に、炉壁から出た光
も光検出器に入射し、それが検出誤差の要因になる。
Further, in the alloying furnace, since light is emitted from the furnace wall, in addition to the reflected light from the steel plate, the light emitted from the furnace wall also enters the photodetector, which causes a detection error.

【0010】従って本発明は、鋼板の振動やパスライン
変動が生じている時でも、正確に合金化度を測定するこ
とを第1の課題とし、炉壁からの発光によって生じる測
定誤差をなくすることを第2の課題とする。
Therefore, the first object of the present invention is to accurately measure the alloying degree even when vibrations of the steel sheet and fluctuations of the pass line occur, and eliminate the measurement error caused by the light emission from the furnace wall. This is the second issue.

【0011】[0011]

【課題を解決するための手段】上記第1の課題を解決す
るために、第1番の発明においては、ライン上を搬送さ
れている亜鉛メッキ鋼板の合金化度を計測する方法にお
いて、亜鉛メッキ鋼板の表面に光を照射するとともに、
該照射光の位置を亜鉛メッキ鋼板の搬送方向及び幅方向
に面状に繰り返し走査し、前記照射光の正反射方向の、
亜鉛メッキ鋼板の表面からそのパスライン変動に比べて
充分に大きな距離を隔てた位置に配置した受光器によ
り、反射光の強度を実質上連続的に検出し、少なくとも
1回の面走査の中で検出された反射光強度分布の最大値
に基づいて、合金化度を求める。
In order to solve the above-mentioned first problem, in the first invention, in the method for measuring the alloying degree of a galvanized steel sheet being conveyed on a line, galvanization is performed. While irradiating the surface of the steel plate with light,
The position of the irradiation light is repeatedly scanned in a plane shape in the conveying direction and the width direction of the galvanized steel sheet, and in the regular reflection direction of the irradiation light,
The intensity of the reflected light is detected substantially continuously by a photodetector placed at a position that is sufficiently large distance from the surface of the galvanized steel plate compared to the variation of the pass line, and at least during one surface scan. The alloying degree is obtained based on the maximum value of the detected reflected light intensity distribution.

【0012】更に前記第2の課題を解決するために、第
2番の発明では、亜鉛メッキ鋼板の表面に照射する光を
一時的に遮断し、その時に前記受光器で検出された受光
強度を背景光レベルとし、少なくとも1回の面走査の中
で検出された反射光強度分布の最大値と前記背景光レベ
ルとの差分に基づいて合金化度を求める。
Further, in order to solve the second problem, in the second invention, the light irradiating the surface of the galvanized steel sheet is temporarily blocked, and at that time, the received light intensity detected by the photodetector is changed. As the background light level, the alloying degree is obtained based on the difference between the maximum value of the reflected light intensity distribution detected during at least one surface scan and the background light level.

【0013】また第3番の発明では、亜鉛メッキ鋼板の
表面に照射する光を一時的に遮断し、その時に前記受光
器で検出された受光強度を背景光レベルとし、少なくと
も1回の面走査の中で検出された反射光強度分布の中で
の最大値が現われた位置に応じて、該最大値に走査角度
の補正を施し、補正された前記最大値と前記背景光レベ
ルとの差分に基づいて合金化度を求める。
According to the third aspect of the invention, the light irradiating the surface of the galvanized steel sheet is temporarily blocked, and the received light intensity detected by the photodetector at that time is set as the background light level, and at least one surface scanning is performed. In accordance with the position where the maximum value in the reflected light intensity distribution detected in appears, the maximum value is corrected for the scanning angle, and the difference between the corrected maximum value and the background light level is calculated. The degree of alloying is calculated based on

【0014】また第4番の発明では、亜鉛メッキ鋼板の
表面に照射する光を一時的に遮断し、その時に前記受光
器で検出された受光強度を背景光レベルとし、1回の面
走査の中で検出された反射光強度分布の最大値と前記背
景光レベルとの差分を、複数回の面走査について平均化
し、その結果に基づいて合金化度を求める。
Further, in the fourth aspect of the invention, the light irradiating the surface of the galvanized steel sheet is temporarily cut off, and the received light intensity detected by the photodetector at that time is set as the background light level, and one surface scanning is performed. The difference between the maximum value of the reflected light intensity distribution detected therein and the background light level is averaged over a plurality of surface scans, and the alloying degree is obtained based on the result.

【0015】また第5番の発明では、亜鉛メッキ鋼板の
表面に照射する光を一時的に遮断し、その時に前記受光
器で検出された受光強度に対応する信号レベルを背景光
レベルとし、該背景光レベルに比例する一定の電流を前
記受光器の信号を処理する回路に注入し、該電流を少な
くとも1回の面走査時間保持する。
In the fifth aspect of the invention, the light irradiating the surface of the galvanized steel sheet is temporarily blocked, and the signal level corresponding to the received light intensity detected by the photodetector at that time is set as the background light level. A constant current proportional to the background light level is injected into the signal processing circuit of the photoreceiver and the current is held for at least one surface scan time.

【0016】[0016]

【作用】本発明においては、亜鉛メッキ鋼板の表面に光
を照射し、該鋼板からの正反射光の強度に基づいて合金
化度を求めている。前述のように、ライン上を搬送され
ている亜鉛メッキ鋼板は、振動やパスライン変動を生じ
るので、鋼板に光を照射する光源の位置が一定であって
も、正反射光の向かう方向,及び光源から受光器までの
光路長は変動する。しかし本発明では、照射光の位置を
亜鉛メッキ鋼板の搬送方向及び幅方向に面状に繰り返し
走査するので、正反射光の方向が変化しても1回の面走
査の間には、必ず受光器に正反射光が入射することにな
り、受光レベルの最大値を正反射光の強度として確実に
検出することができ、それに基づいて正確な合金化度を
求めることができる。しかも、反射光を検出する位置
は、亜鉛メッキ鋼板の表面からそのパスライン変動に比
べて充分に大きな距離を隔てた位置であるので、パスラ
インの変動による光源から受光器までの光路長の変動
は、大きな検出誤差を生じない。
In the present invention, the surface of the galvanized steel sheet is irradiated with light, and the degree of alloying is determined based on the intensity of the specularly reflected light from the steel sheet. As described above, the galvanized steel sheet conveyed on the line causes vibrations and path line fluctuations. Therefore, even if the position of the light source that irradiates the steel sheet with light is constant, the direction of the specular reflection light, and The optical path length from the light source to the light receiver varies. However, in the present invention, since the position of the irradiation light is repeatedly scanned in a plane shape in the conveying direction and the width direction of the galvanized steel sheet, even if the direction of the specular reflection light changes, the light reception is always performed during one surface scanning. Since the specularly reflected light is incident on the vessel, the maximum value of the received light level can be reliably detected as the intensity of the specularly reflected light, and the accurate degree of alloying can be obtained based on this. Moreover, since the position where the reflected light is detected is a position that is sufficiently larger than the path line variation from the surface of the galvanized steel sheet, the variation of the optical path length from the light source to the light receiver due to the variation of the path line. Does not cause a large detection error.

【0017】また第2番の発明では、炉壁からの発光に
よって生じる測定誤差をなくすることができる。即ち、
亜鉛メッキ鋼板の表面に照射する光を一時的に遮断する
ことによって、炉壁からの発光などによる外来光の強度
(背景光レベル)のみを受光器で検出することができ、
反射光強度分布の最大値と背景光レベルとの差分をとる
ことによって、外来光成分を除外した正反射光のみのレ
ベルを正確に求めることができる。
Further, in the second aspect of the invention, it is possible to eliminate the measurement error caused by the light emission from the furnace wall. That is,
By temporarily shutting off the light that illuminates the surface of the galvanized steel sheet, it is possible to detect only the intensity of external light (background light level) due to light emission from the furnace wall (background light level),
By taking the difference between the maximum value of the reflected light intensity distribution and the background light level, it is possible to accurately obtain the level of only regular reflection light excluding the extraneous light component.

【0018】また第3番の発明では、更に鋼板の振動
(角度)によって生じる誤差を低減しうる。光が照射さ
れる鋼板面の角度に応じて、正反射光が受光器に入射す
る時の、受光器検出面での入射角、ならびに鋼板表面で
の入射角及び反射角が変化するので、1回の走査の間に
受光器で検出される最大値の大きさも、鋼板面の角度の
影響を受けて変動する。鋼板面の角度が変化すると、1
回の走査の間の最大受光レベルが現われる位置(タイミ
ング)が変化するので、この発明では最大受光レベルが
検出された位置によって鋼板の角度を検出し、検出した
角度に応じて生じうる最大受光レベルの誤差を補正して
いる。
Further, in the third aspect of the invention, the error caused by the vibration (angle) of the steel sheet can be further reduced. Depending on the angle of the steel plate surface to which the light is irradiated, the incident angle on the detector surface when the specularly reflected light enters the light receiver, and the incident angle and the reflection angle on the steel plate surface change. The magnitude of the maximum value detected by the light receiver during one scanning also changes due to the influence of the angle of the steel plate surface. When the angle of the steel plate surface changes, 1
Since the position (timing) at which the maximum light receiving level appears during one scanning changes, the present invention detects the angle of the steel sheet according to the position where the maximum light receiving level is detected, and the maximum light receiving level that can occur according to the detected angle. The error of is corrected.

【0019】また第4番の発明では、亜鉛メッキ鋼板表
面に合金化むら等がある場合でも、異常な合金化度が検
出されるのを防止しうる。即ち、亜鉛メッキ鋼板表面に
は、局部的に、合金化むらが生じたり、粒子状の亜鉛が
付着した部分が生じる場合があるので、その部分からの
反射光レベルを含む1回の面走査のみの反射光強度分布
の最大値を使用すると、異常な合金化度が一時的に検出
される。しかしこの発明では、複数回の面走査で得られ
た検出値を平均化し、その結果に基づいて合金化度を求
めるので、実際に鋼板の合金化度が異常でない限り、異
常な合金化度が検出されることはない。
Further, according to the fourth aspect of the present invention, it is possible to prevent the abnormal degree of alloying from being detected even when there is uneven alloying on the surface of the galvanized steel sheet. That is, the galvanized steel sheet surface may locally have uneven alloying or a portion where particulate zinc is adhered. Therefore, only one surface scanning including the reflected light level from the portion may occur. When the maximum value of the reflected light intensity distribution of is used, an abnormal alloying degree is temporarily detected. However, in the present invention, the detected values obtained by a plurality of surface scans are averaged, and the alloying degree is obtained based on the result, so unless the alloying degree of the steel sheet is actually abnormal, the abnormal alloying degree is It will never be detected.

【0020】また第5番の発明では、背景光レベルの変
化によって、信号処理回路のレベルが飽和するのを防止
しうる。受光器には、鋼板からの反射光と炉壁の発光な
どによる背景光が入射するが、背景光のレベルは炉温変
化等に応じて大きく変化する。背景光レベルが変化する
と、受光器の出力レベルが変動するので、受光器の信号
を処理する回路で入力レベルの飽和等が生じ、最大値が
正確に検出できない場合が生じる。しかしこの発明で
は、亜鉛メッキ鋼板の表面に照射する光を遮断した時に
受光器で検出された受光強度に対応する信号レベルを、
背景光レベルとし、背景光レベルに比例する一定の電流
を、受光器の信号を処理する回路に注入し、該電流を少
なくとも1回の面走査時間保持するので、注入する電流
によって背景光レベルを打ち消し、反射光を受光しない
時の信号処理回路の入力レベルを実質上零にすることが
でき、それによって信号レベルの飽和が防止される。
In the fifth aspect of the invention, it is possible to prevent the level of the signal processing circuit from being saturated due to the change of the background light level. Reflected light from the steel plate and background light due to light emission from the furnace wall are incident on the light receiver, but the level of the background light greatly changes according to the change in the furnace temperature and the like. When the background light level changes, the output level of the photodetector fluctuates, so that the circuit that processes the signal of the photodetector causes saturation of the input level and the like, and the maximum value may not be accurately detected. However, in the present invention, the signal level corresponding to the received light intensity detected by the photodetector when the light irradiating the surface of the galvanized steel sheet is blocked,
The background light level is set, and a constant current proportional to the background light level is injected into the signal processing circuit of the photodetector, and the current is held for at least one surface scanning time. The input level of the signal processing circuit when canceling and not receiving the reflected light can be made substantially zero, thereby preventing saturation of the signal level.

【0021】[0021]

【実施例】本発明を実施する製造ラインの一部分を図3
に示す。図3を参照すると、この工程に入る鋼板は、ま
ず亜鉛ポット内の460℃の溶融亜鉛浴に浸漬され、そ
の表面に亜鉛メッキが付着する。亜鉛メッキ層が形成さ
れた鋼板は、亜鉛ポットから鉛直方向に搬送され、保熱
炉に向かう。500〜600℃の温度に制御された保熱
炉の内部を通る時に、拡散によって、鋼板表面に亜鉛と
鉄の合金が形成される。温度が高ければ高いほど、また
鋼板の炉内滞留時間が長ければ長いほど、合金化が進行
する。
FIG. 3 shows a part of a production line for carrying out the present invention.
Shown in. Referring to FIG. 3, the steel sheet that enters this process is first immersed in a molten zinc bath at 460 ° C. in a zinc pot, and zinc plating adheres to its surface. The steel sheet on which the galvanized layer is formed is conveyed vertically from the zinc pot and heads for the heat retention furnace. An alloy of zinc and iron is formed on the surface of the steel sheet by diffusion when passing through the inside of the heat-retaining furnace controlled at a temperature of 500 to 600 ° C. The higher the temperature and the longer the residence time of the steel sheet in the furnace, the more alloying proceeds.

【0022】鋼板の合金化度を測定するために、保熱炉
の壁面には3個の合金化センサが互いに異なる位置に設
置されている。3個の合金化センサが出力する電気信号
は、演算盤に入力される。各々の合金化センサは、ステ
ンレス製の円柱形状の容器に収めてあり、その全周囲が
水冷されている。容器の形状を円柱状にしたのは、水圧
が周囲に均等にかかるように配慮したものである。合金
化センサの検出面は、石英ガラスを介して、壁面の開口
部と対向している。炉内から飛散してくる亜鉛ヒュ−ム
が石英ガラスに付着すると、測定に悪影響を及ぼすの
で、石英ガラスの周囲から炉内に向かって窒素ガスを噴
射(窒素パ−ジ)している。水冷のための水及び窒素パ
−ジのためのガスは、各合金化センサの近傍に配置した
バルブスタンドを介して供給される。
In order to measure the alloying degree of the steel sheet, three alloying sensors are installed at different positions on the wall surface of the heat insulation furnace. The electric signals output from the three alloying sensors are input to the arithmetic board. Each alloyed sensor is housed in a stainless steel cylindrical container, and the entire circumference thereof is water-cooled. The cylindrical shape of the container is designed so that the water pressure is evenly applied to the surroundings. The detection surface of the alloying sensor faces the opening of the wall surface with the quartz glass in between. If zinc fume scattered from the inside of the furnace adheres to the quartz glass, it adversely affects the measurement. Therefore, nitrogen gas is sprayed from the periphery of the quartz glass into the furnace (nitrogen purge). Water for water cooling and gas for nitrogen purging are supplied through a valve stand located near each alloying sensor.

【0023】保熱炉及び1つの合金化センサの横断面を
図1に拡大して示す。図1を参照して説明する。保熱炉
の壁1には測定のために開口1aが形成されている。こ
の開口1aと対向して、合金化センサが設置されてい
る。合金化センサのケ−シング2は、ヒンジ4によって
壁1に取付けてある。ケ−シング2は、前述のように円
柱形状になっており、検出面の開口部には、石英ガラス
3が装着されている。
A cross-section of the furnace and one alloyed sensor is shown enlarged in FIG. This will be described with reference to FIG. An opening 1a is formed in the wall 1 of the heat retention furnace for measurement. An alloying sensor is installed so as to face the opening 1a. The alloying sensor casing 2 is attached to the wall 1 by a hinge 4. The casing 2 has a cylindrical shape as described above, and the quartz glass 3 is attached to the opening of the detection surface.

【0024】ケ−シング2の内部には、レ−ザ光源5,
縦走査ミラ−6,横走査ミラ−7,受光ユニット8及び
処理ユニット10が設置されている。図示しないが、縦
走査ミラ−6及び横走査ミラ−7にはそれぞれ走査機構
が備わっており、前者はミラ−の中央部を中心として上
下方向(鋼板の長さ方向)に反射方向が変わるように揺
動し、後者はミラ−の中央部を中心として左右(鋼板の
幅方向)に反射方向が変わるように揺動する。縦走査ミ
ラ−6は揺動周波数が350Hz、揺動角度が±7.5
度であり、横走査ミラ−7は揺動周波数が20Hz、揺
動角度が±10度になっている。
Inside the casing 2, a laser light source 5,
A vertical scanning mirror 6, a horizontal scanning mirror 7, a light receiving unit 8 and a processing unit 10 are installed. Although not shown, each of the vertical scanning mirror 6 and the horizontal scanning mirror 7 has a scanning mechanism. In the former, the reflection direction is changed in the vertical direction (the length direction of the steel plate) about the center of the mirror. The latter oscillates so that the reflection direction changes left and right (the width direction of the steel plate) about the center of the mirror. The vertical scanning mirror-6 has a swing frequency of 350 Hz and a swing angle of ± 7.5.
The horizontal scanning mirror 7 has a swing frequency of 20 Hz and a swing angle of ± 10 degrees.

【0025】レ−ザ光源5は、半導体レ−ザ発振器であ
り、出力レベルを一定に維持する自動調整機構を内蔵し
ている。レ−ザ光源5から出たレ−ザ光は、まず縦走査
ミラ−6に向かい、縦走査ミラ−6及び横走査ミラ−7
の各面で反射して鋼板の表面に照射される。縦走査ミラ
−6及び横走査ミラ−7は常時揺動しているので、鋼板
の表面に照射されるレ−ザ光の位置は、鋼板の表面上を
縦方向及び横方向に所定範囲で繰り返し走査され、面走
査される。鋼板表面に入射したレ−ザ光の正反射光は、
鋼板表面に対する入射角と一致する反射角の方向に現わ
れ、その強度は鋼板表面の光反射率によって定まる。鋼
板表面の光反射率は、後述するように合金化度によって
変化するので、正反射光の強度に基づいて、合金化度を
測定することができる。
The laser light source 5 is a semiconductor laser oscillator and has a built-in automatic adjusting mechanism for maintaining a constant output level. The laser light emitted from the laser light source 5 first goes to the vertical scanning mirror 6 and then the vertical scanning mirror 6 and the horizontal scanning mirror 7.
Is reflected on each surface of the steel sheet and irradiated on the surface of the steel sheet. Since the vertical scanning mirror 6 and the horizontal scanning mirror 7 are constantly oscillating, the position of the laser light irradiated on the surface of the steel sheet is repeated on the surface of the steel sheet in a predetermined range in the vertical and horizontal directions. Scanned and surface scanned. The specular reflection light of the laser light incident on the steel plate surface is
It appears in the direction of the reflection angle that coincides with the incident angle to the steel plate surface, and its intensity is determined by the light reflectance of the steel plate surface. Since the light reflectance of the steel plate surface changes depending on the alloying degree as described later, the alloying degree can be measured based on the intensity of specularly reflected light.

【0026】この正反射光が届く位置に、受光ユニット
8が配置されている。受光ユニットの受光面には、凸レ
ンズが装着されており、入射した光を収束させて、面形
受光素子であるフォトダイオ−ド9の面に導く。鋼板
は、炉の近傍で全く支持されていないので、様々な方向
に対して振動やパスラインの変動が生じる。振動によっ
て鋼板表面の角度が変化すると、レ−ザ光の入射角及び
反射角が変化し、正反射光の届く位置が変化することに
なるが、この実施例ではレ−ザ光を振動周波数(数H
z)に比べて高い周波数で面走査しているので、1回の
面走査をする間には、短時間ではあるが確実に正反射光
が受光ユニット8に入射する。また、パスラインの変
動、即ち鋼板に生じうる位置ずれは±50mm程度であ
るが、ミラ−7と鋼板との距離、及び鋼板と受光ユニッ
ト8との距離をそれに比べて充分に大きく(800m
m)してあるので、パスラインの変動による光源から受
光器までの光路長の変化は小さく、それに伴なう受光ユ
ニット8での入射光の強度変動は小さい。
The light receiving unit 8 is arranged at a position where the regular reflection light reaches. A convex lens is attached to the light receiving surface of the light receiving unit to converge the incident light and guide it to the surface of the photodiode 9 which is a planar light receiving element. Since the steel plate is not supported near the furnace at all, vibration and fluctuation of the pass line occur in various directions. When the angle of the steel plate surface changes due to vibration, the incident angle and the reflection angle of the laser light change, and the position where the specular reflection light reaches changes, but in this embodiment, the laser light is changed to the vibration frequency ( Number H
Since surface scanning is performed at a frequency higher than that of z), specular reflection light surely enters the light receiving unit 8 for a short time during one surface scanning. Further, the variation of the pass line, that is, the positional deviation that can occur in the steel sheet is about ± 50 mm, but the distance between the mirror 7 and the steel sheet and the distance between the steel sheet and the light receiving unit 8 are sufficiently large (800 m).
m), the change in the optical path length from the light source to the light receiver due to the change in the pass line is small, and the accompanying change in the intensity of the incident light in the light receiving unit 8 is small.

【0027】合金化センサと炉の壁面との間には、開口
部1aを閉塞しうるシャッタ板11が配置されており、
該シャッタ板11の合金化センサ側の面には、光反射率
が一定の校正板12が装着されている。測定時にはシャ
ッタ板11は図1のように開かれているが、これを動か
して開口部1aを閉塞することにより、ミラ−7から出
たレ−ザ光が校正板12の表面で、所定の反射率で反射
して受光ユニット8に入射するので、この時の受光レベ
ルに基づいて、合金化センサの特性を校正することがで
きる。
A shutter plate 11 capable of closing the opening 1a is arranged between the alloying sensor and the wall surface of the furnace.
A calibration plate 12 having a constant light reflectance is mounted on the surface of the shutter plate 11 on the alloyed sensor side. At the time of measurement, the shutter plate 11 is opened as shown in FIG. 1. By moving the shutter plate 11 to close the opening 1a, the laser light emitted from the mirror 7 is moved to a predetermined level on the surface of the calibration plate 12. Since the light is reflected at the reflectance and enters the light receiving unit 8, the characteristics of the alloying sensor can be calibrated based on the light receiving level at this time.

【0028】1つの合金化センサの電気回路構成を、図
2に示す。図2を参照すると、図1には示されていない
角度センサ21,22及びフォトダイオ−ド23が備わ
っている。角度センサ21及び22は、それぞれ、縦走
査ミラ−6及び横走査ミラ−7の角度(揺動位置)を検
出する。フォトダイオ−ド23は、レ−ザ光源5から出
るレ−ザ光の出力をモニタするために利用される。
The electrical circuit configuration of one alloyed sensor is shown in FIG. Referring to FIG. 2, angle sensors 21 and 22 and a photodiode 23, which are not shown in FIG. 1, are provided. The angle sensors 21 and 22 detect the angles (swing position) of the vertical scanning mirror 6 and the horizontal scanning mirror 7, respectively. The photodiode 23 is used to monitor the output of the laser light emitted from the laser light source 5.

【0029】フォトダイオ−ド9は、受光強度に比例し
た電流信号を出力する。この信号は、プリアンプ31に
よって増幅され、その出力レベルがA/D変換器32に
よってデジタル量に変換される。制御ユニット35は、
図示しないミラ−揺動機構を付勢するミラ−ドライバ
や、走査角度信号に基づいて様々なタイミング信号を生
成する回路を含んでいる。レ−ザドライバ37は、制御
ユニット35が出力するオン/オフ信号に従って、レ−
ザ発振器5の付勢/消勢を制御する。
The photodiode 9 outputs a current signal proportional to the intensity of the received light. This signal is amplified by the preamplifier 31, and its output level is converted into a digital amount by the A / D converter 32. The control unit 35
It includes a mirror driver for energizing a mirror swing mechanism (not shown) and a circuit for generating various timing signals based on the scanning angle signal. The laser driver 37 is responsive to the on / off signal output from the control unit 35 to generate a laser beam.
The energization / de-energization of the oscillator 5 is controlled.

【0030】A/D変換器32から出力される受光レベ
ルの情報は、ピ−ク値検出回路33と背景値検出回路3
6に入力され、ピ−ク値検出回路33が出力するピ−ク
値は角度補正演算回路34に入力される。そして、角度
補正演算回路34の出力レベルから背景値検出回路36
の出力レベルを減算した値が、移動平均演算回路40に
入力される。移動平均演算回路40が出力する値は、D
/A変換器41によってアナログ電圧信号に変換され、
更にV/I変換器42によって電流信号に変換され、測
定結果として出力される。
The information on the received light level output from the A / D converter 32 is the peak value detection circuit 33 and the background value detection circuit 3.
The peak value input to 6 and output from the peak value detection circuit 33 is input to the angle correction calculation circuit 34. Then, from the output level of the angle correction calculation circuit 34, the background value detection circuit 36
The value obtained by subtracting the output level of is input to the moving average calculation circuit 40. The value output by the moving average calculation circuit 40 is D
Is converted into an analog voltage signal by the / A converter 41,
Further, it is converted into a current signal by the V / I converter 42 and output as a measurement result.

【0031】図4は、受光ユニット8で検出される受光
レベルの、面走査の2回分の変化を、3種類のそれぞれ
について示している。最上部に示すのは、鋼板が標準的
な状態(角度)にある時のものであり、中央に示すの
は、鋼板の縦方向の振動によって鋼板の角度が標準状態
に比べて縦方向にずれた時のものであり、下に示すの
は、鋼板の横方向の振動によって鋼板の角度が標準状態
に比べて横方向にずれた時のものである。
FIG. 4 shows changes in the light-receiving level detected by the light-receiving unit 8 for two surface scans for each of the three types. The top part is when the steel plate is in the standard state (angle), and the center part is that the steel plate angle is shifted in the vertical direction compared to the standard state due to the vertical vibration of the steel plate. What is shown below is when the angle of the steel sheet is laterally displaced from the standard state due to the lateral vibration of the steel sheet.

【0032】図4を参照すると、受光レベルは縦走査及
び横走査に伴なって振動的に変化しているが、1回の面
走査の中での最大値が現われる時が、正反射光が受光ユ
ニット8に入射した時であると考えられる。この面走査
毎の最大値の大きさが、図2のピ−ク値検出回路33に
よって検出され、角度補正演算回路に出力される。
Referring to FIG. 4, the received light level changes oscillatingly in accordance with the vertical scanning and the horizontal scanning, but when the maximum value appears in one surface scanning, the specularly reflected light is emitted. It is considered that it is when the light enters the light receiving unit 8. The magnitude of the maximum value for each surface scan is detected by the peak value detection circuit 33 in FIG. 2 and output to the angle correction calculation circuit.

【0033】但し、ピ−ク値検出回路33で検出される
最大値は、正反射光の他に、炉壁の発光によって生じた
外来光の成分も含んでいる。そこでこの実施例では、背
景値検出回路36によって、外来光レベルを検出してい
る。即ち、各面走査と面走査との間に、約1msec のレ
−ザ休止期間を設け、その時にレ−ザ発振器5を消勢
し、これに同期して、A/D変換器32が出力する受光
レベル、即ち外来光レベルを背景値検出回路36が保持
するように制御している。この外来光レベルを検出され
た最大値から減算することによって、外来光の影響を除
外した受光レベル、即ち鋼板の光反射率に応じた信号レ
ベルが得られる。
However, the maximum value detected by the peak value detection circuit 33 includes, in addition to the specular reflection light, the component of the external light generated by the light emission of the furnace wall. Therefore, in this embodiment, the background light detection circuit 36 detects the external light level. That is, a laser pause period of about 1 msec is provided between each surface scan, the laser oscillator 5 is deactivated at that time, and the A / D converter 32 outputs in synchronization with this. The background value detection circuit 36 is controlled to hold the received light level, that is, the external light level. By subtracting this external light level from the detected maximum value, the received light level excluding the influence of the external light, that is, the signal level according to the light reflectance of the steel plate can be obtained.

【0034】実際には、鋼板の振動によって鋼板の角度
が変化すると、図5に示すように受光レベルが変動し、
標準状態の鋼板角度からのずれが大きくなるに従って、
受光レベルは低下する。このような角度の影響を除外す
るために、図2の角度補正演算回路34では、補正処理
を実施している。角度のずれ量と受光レベルの低下量と
の関係は、図5から分かるようにほぼ一定である。そこ
で、この実施例では、各々の角度ずれ量に対応する定数
を配置したメモリテ−ブルが、角度補正演算回路34内
に備わっている。そして、検出した角度ずれ量から、前
記メモリテ−ブルを検索して必要な定数を入力し、それ
を前記最大値に掛けて、補正後の最大値を求めている。
Actually, when the angle of the steel plate changes due to the vibration of the steel plate, the received light level changes as shown in FIG.
As the deviation from the steel plate angle in the standard state increases,
The received light level decreases. In order to exclude the influence of such an angle, the angle correction calculation circuit 34 of FIG. 2 performs a correction process. As can be seen from FIG. 5, the relationship between the angle shift amount and the light reception level reduction amount is substantially constant. Therefore, in this embodiment, a memory table in which constants corresponding to the respective angular deviations are arranged is provided in the angle correction arithmetic circuit 34. Then, the memory table is searched from the detected amount of angular deviation, a necessary constant is input, and the maximum value is multiplied to obtain the corrected maximum value.

【0035】角度ずれ量は、図4から分かるように、最
大値が検出される走査位置から求めることができる。即
ち、縦方向の角度ずれ量は、縦走査周期内の最大値が検
出される位置(位相)の変化として検出でき、横方向の
角度ずれ量は、横走査周期内の最大値が検出される位置
(位相)の変化として検出できる。つまりこれらは、走
査の基準タイミングから、最大値が検出される時までの
経過時間の変化として検出される。
As can be seen from FIG. 4, the amount of angular deviation can be obtained from the scanning position where the maximum value is detected. That is, the amount of angular deviation in the vertical direction can be detected as a change in the position (phase) at which the maximum value in the vertical scanning cycle is detected, and the amount of angular deviation in the horizontal direction can be detected as the maximum value in the horizontal scanning cycle. It can be detected as a change in position (phase). That is, these are detected as changes in the elapsed time from the scanning reference timing to the time when the maximum value is detected.

【0036】図2の装置においては、ピ−ク値検出回路
33が最大値を検出した時に出力する信号に同期して、
走査角度保持回路39が、制御ユニット35の出力する
縦走査角及び横走査角の情報をそれぞれ保持するので、
角度補正演算回路34は、走査角度保持回路39が保持
した縦走査角及び横走査角の情報を入力し、それに基づ
いて補正演算を実施している。
In the apparatus of FIG. 2, in synchronization with the signal output when the peak value detection circuit 33 detects the maximum value,
Since the scanning angle holding circuit 39 holds the information of the vertical scanning angle and the horizontal scanning angle output from the control unit 35,
The angle correction calculation circuit 34 inputs the information of the vertical scanning angle and the horizontal scanning angle held by the scanning angle holding circuit 39, and performs the correction calculation based on the information.

【0037】ところで、鋼板表面には、合金化むらなど
が生じる場合があるので、検出される受光レベルの最大
値が異常に大きくなったり小さくなったりする場合があ
り、1回の面走査の結果だけを利用すると、測定誤差が
生じ易い。そこでこの実施例では、移動平均演算回路4
0において、それまでの過去40回の面走査で得られた
値から、移動平均値を求め、その計算結果を出力するよ
うに構成してある。
By the way, since uneven alloying or the like may occur on the surface of the steel sheet, the maximum value of the received light level detected may become abnormally large or small. As a result of one surface scanning. If only the above is used, a measurement error is likely to occur. Therefore, in this embodiment, the moving average calculation circuit 4
At 0, the moving average value is obtained from the values obtained in the past 40 surface scans, and the calculation result is output.

【0038】以上のように、各々の合金化センサは、鋼
板表面の光反射率に応じた電気信号を出力する。鋼板の
合金化の進行に伴なう光反射率の変化を図6に示す。反
射率の0.2〜0.3程度の範囲が適正合金化範囲であ
るが、合金化が進行するに従って、光反射率が低下し、
ある程度、合金化が進むと、適正合金化範囲に入る。こ
の実施例では、図3に示すように3個の合金化センサが
互いに異なる位置に配置されているので、演算盤は、3
個の合金化センサの出力値を参照することによって、ど
の位置で鋼板が適正合金化範囲に入ったかを調べること
ができる。その結果を利用して、保熱炉の温度を調整し
たり、保熱炉における鋼板の滞留時間を調整することに
よって、消費エネルギ−量を最小にし、また鋼板の合金
化度を適正に維持することが可能になる。
As described above, each alloying sensor outputs an electric signal corresponding to the light reflectance of the steel plate surface. FIG. 6 shows changes in the light reflectance with the progress of alloying of the steel sheet. A range of about 0.2 to 0.3 of reflectance is a proper alloying range, but as the alloying progresses, the light reflectance decreases,
When alloying progresses to some extent, it enters the proper alloying range. In this embodiment, the three alloying sensors are arranged at different positions as shown in FIG.
By referring to the output values of the individual alloying sensors, it is possible to check at which position the steel sheet is within the proper alloying range. By utilizing the result, the energy consumption is minimized and the alloying degree of the steel sheet is appropriately maintained by adjusting the temperature of the heat retaining furnace or adjusting the residence time of the steel sheet in the heat retaining furnace. It will be possible.

【0039】再び図2を参照すると、プリアンプ31が
出力する信号は、サンプルホ−ルド回路38にも入力さ
れる。また、サンプルホ−ルド回路38の制御入力端子
には、制御ユニット35が出力するレ−ザ付勢信号が印
加されている。このため、サンプルホ−ルド回路38
は、レ−ザ発振器5が消勢されている時に、プリアンプ
31が出力する信号のレベルをサンプリングし、そのレ
ベルを保持するとともに、そのレベルに応じた電流をプ
リアンプ31の入力端子に注入し、該電流を少なくとも
1回の面走査時間保持する。この時の電流値は、フォト
ダイオ−ド9が出力している電流と一致するように予め
調整されている。レ−ザ発振器5が付勢されている時に
は、サンプルホ−ルド回路38が保持するレベルは変化
せず、それがプリアンプ31に注入する電流値も変化し
ない。従って、レ−ザ発振器5を消勢した時、即ち反射
光が全くない時にフォトダイオ−ド9が出力する電流分
を打ち消すように、それと同一レベルの補償電流が逆方
向に注入される。このため、炉壁からの発光による外来
光の強度が大きくなった場合でも、プリアンプ31の入
力レベルが飽和する恐れはなく、正反射光の正しい受光
レベルが検出される。
Referring again to FIG. 2, the signal output from the preamplifier 31 is also input to the sample hold circuit 38. A laser energizing signal output from the control unit 35 is applied to the control input terminal of the sample hold circuit 38. Therefore, the sample hold circuit 38
Is to sample the level of the signal output from the preamplifier 31 when the laser oscillator 5 is deactivated, hold the level, and inject a current corresponding to the level into the input terminal of the preamplifier 31, The current is held for at least one surface scanning time. The current value at this time is adjusted in advance so as to match the current output by the photodiode 9. When the laser oscillator 5 is energized, the level held by the sample hold circuit 38 does not change, and the current value it injects into the preamplifier 31 does not change, either. Therefore, when the laser oscillator 5 is deenergized, that is, when there is no reflected light, the compensation current of the same level is injected in the opposite direction so as to cancel the current output by the photodiode 9. Therefore, even when the intensity of the external light due to the light emitted from the furnace wall is increased, the input level of the preamplifier 31 is not likely to be saturated, and the correct reception level of the specular reflection light is detected.

【0040】[0040]

【発明の効果】以上のとおり本発明によれば、照射光の
位置を亜鉛メッキ鋼板の搬送方向及び幅方向に面状に繰
り返し走査するので、正反射光の方向が変化しても1回
の面走査の間には、必ず受光器に正反射光が入射するこ
とになり、受光レベルの最大値を正反射光の強度として
確実に検出することができ、それに基づいて正確な合金
化度を求めることができる。しかも、反射光を検出する
位置は、亜鉛メッキ鋼板の表面からそのパスライン変動
に比べて充分に大きな距離を隔てた位置であるので、パ
スラインの変動による光源から受光器までの光路長の変
動によって、大きな検出誤差は生じない。
As described above, according to the present invention, the position of the irradiation light is repeatedly scanned in the plane direction in the conveying direction and the width direction of the galvanized steel sheet, so that even if the direction of the specular reflection light is changed, During surface scanning, specularly reflected light always enters the light receiver, and the maximum value of the received light level can be reliably detected as the intensity of specularly reflected light. You can ask. Moreover, since the position where the reflected light is detected is a position that is sufficiently larger than the path line variation from the surface of the galvanized steel sheet, the variation of the optical path length from the light source to the light receiver due to the variation of the path line. Does not cause a large detection error.

【0041】また第2番の発明では、炉壁からの発光に
よって生じる測定誤差をなくすることができる。即ち、
亜鉛メッキ鋼板の表面に照射する光を一時的に遮断する
ことによって、炉壁からの発光などによる外来光の強度
(背景光レベル)のみを受光器で検出することができ、
反射光強度分布の最大値と背景光レベルとの差分をとる
ことによって、外来光成分を除外した正反射光のみのレ
ベルを正確に求めることができる。
In the second aspect of the invention, it is possible to eliminate the measurement error caused by the light emission from the furnace wall. That is,
By temporarily shutting off the light that illuminates the surface of the galvanized steel sheet, it is possible to detect only the intensity of external light (background light level) due to light emission from the furnace wall (background light level),
By taking the difference between the maximum value of the reflected light intensity distribution and the background light level, it is possible to accurately obtain the level of only regular reflection light excluding the extraneous light component.

【0042】また第3番の発明では、更に鋼板の振動
(角度)によって生じる誤差を低減しうる。即ち、光が
照射される鋼板面の角度に応じて、正反射光が受光器に
入射する時の、受光器検出面での入射角、ならびに鋼板
表面での入射角及び反射角が変化し、1回の走査の間に
受光器で検出される最大値の大きさも、鋼板面の角度の
影響を受けて変動するので、最大受光レベルが検出され
た位置から鋼板の角度を検出し、検出した角度に応じて
生じうる最大受光レベルの誤差を補正しうる。
Further, in the third aspect of the invention, the error caused by the vibration (angle) of the steel plate can be further reduced. That is, depending on the angle of the steel plate surface irradiated with light, when the specularly reflected light is incident on the light receiver, the incident angle at the photodetector detection surface, and the incident angle and the reflection angle at the steel plate surface change, The magnitude of the maximum value detected by the light receiver during one scanning also changes due to the influence of the angle of the steel plate surface, so the angle of the steel plate was detected from the position where the maximum light receiving level was detected, and was detected. It is possible to correct the error of the maximum light receiving level that may occur depending on the angle.

【0043】また第4番の発明では、亜鉛メッキ鋼板表
面に合金化むら等がある場合でも、異常な合金化度が検
出されるのを防止しうる。即ち、亜鉛メッキ鋼板表面に
は、局部的に、合金化むらが生じたり、粒子状の亜鉛が
付着した部分が生じる場合があるので、その部分からの
反射光レベルを含む1回の面走査のみの反射光強度分布
の最大値を使用すると、異常な合金化度が一時的に検出
される場合が生じるが、複数回の面走査で得られた検出
値を平均化し、その結果に基づいて合金化度を求めるこ
とによって、平均化された、つまり正しい合金化度が検
出される。
Further, in the fourth aspect of the present invention, it is possible to prevent the abnormal degree of alloying from being detected even when there is uneven alloying or the like on the surface of the galvanized steel sheet. That is, the galvanized steel sheet surface may locally have uneven alloying or a portion where particulate zinc is adhered. Therefore, only one surface scanning including the reflected light level from the portion may occur. When the maximum value of the reflected light intensity distribution of is used, an abnormal alloying degree may be detected temporarily, but the detected values obtained by multiple surface scans are averaged, and based on the result, By determining the degree of alloying, the averaged or correct degree of alloying is detected.

【0044】また第5番の発明では、背景光レベルの変
化によって、信号処理回路のレベルが飽和するのを防止
しうる。受光器には、鋼板からの反射光と炉壁の発光な
どによる背景光が入射するが、背景光のレベルは炉温変
化等に応じて大きく変化する。背景光レベルが変化する
と、受光器の出力レベルが変動するので、受光器の信号
を処理する回路(図2のプリアンプ31)で入力レベル
の飽和等が生じ、最大値が正確に検出できない場合が生
じる。しかしこの発明では、亜鉛メッキ鋼板の表面に照
射する光を遮断した時に受光器で検出された受光強度に
対応する信号レベルを、背景光レベルとして保持し、背
景光レベルに比例する一定の電流を、受光器の信号を処
理する回路に注入するので、注入する電流によって背景
光レベルを打ち消し、反射光を受光しない時の信号処理
回路の入力レベルを実質上零に近づけることができ、炉
壁からの発光強度が強くなった場合でも、信号レベルの
飽和が防止され、正反射光の正しい受光レベルが検出さ
れる。
In the fifth invention, it is possible to prevent the level of the signal processing circuit from being saturated due to the change of the background light level. Reflected light from the steel plate and background light due to light emission from the furnace wall are incident on the light receiver, but the level of the background light greatly changes according to the change in the furnace temperature and the like. When the background light level changes, the output level of the light receiver fluctuates, so that the input signal may be saturated in the circuit (preamplifier 31 in FIG. 2) that processes the signal of the light receiver, and the maximum value may not be accurately detected. Occurs. However, in the present invention, the signal level corresponding to the received light intensity detected by the light receiver when the light irradiating the surface of the galvanized steel sheet is blocked is held as the background light level, and a constant current proportional to the background light level is maintained. , Since it is injected into the circuit that processes the signal of the photodetector, the background light level is canceled by the injected current, and the input level of the signal processing circuit when the reflected light is not received can be made to approach substantially zero. Even when the emission intensity of the signal becomes strong, the signal level is prevented from being saturated, and the correct light reception level of the specular reflection light is detected.

【図面の簡単な説明】[Brief description of drawings]

【図1】 図3の1つの合金化センサを示す拡大横断面
図である。
FIG. 1 is an enlarged cross-sectional view showing one alloyed sensor of FIG.

【図2】 合金化センサの信号処理回路を示すブロック
図である。
FIG. 2 is a block diagram showing a signal processing circuit of the alloying sensor.

【図3】 本発明を実施する製造ラインの一部分を示す
斜視図である。
FIG. 3 is a perspective view showing a part of a production line for carrying out the present invention.

【図4】 受光レベルの変化の3例を示す波形図であ
る。
FIG. 4 is a waveform diagram showing three examples of changes in light reception level.

【図5】 鋼板角度に応じた受光感度の変化を示すグラ
フである。
FIG. 5 is a graph showing a change in light receiving sensitivity according to a steel plate angle.

【図6】 光反射率の時間変化と適正合金化度の関係を
示すグラフである。
FIG. 6 is a graph showing the relationship between the temporal change in light reflectance and the appropriate degree of alloying.

【符号の説明】[Explanation of symbols]

1:炉壁 1a:開口部 2:ケ−シング 3:石英ガラス 5:レ−ザ光源 6:縦走査ミラ− 7:横走査ミラ− 8:受光ユニット 9:フォトダイオ−ド 10:処理ユニット 21,22:角度センサ 23:フォトダイオ
−ド 31:プリアンプ 32:A/D変換器 33:ピ−ク値検出回路 34:角度補正演算
回路 35:制御ユニット 36:背景値検出回
路 37:レ−ザドライバ 38:サンプルホ−
ルド回路 39:走査角度保持回路 40:移動平均演算
回路 41:D/A変換器 42:V/I変換器
1: Furnace wall 1a: Opening 2: Casing 3: Quartz glass 5: Laser light source 6: Vertical scanning mirror 7: Horizontal scanning mirror 8: Light receiving unit 9: Photodiode 10: Processing unit 21 , 22: angle sensor 23: photo diode 31: preamplifier 32: A / D converter 33: peak value detection circuit 34: angle correction calculation circuit 35: control unit 36: background value detection circuit 37: laser Driver 38: Sample Ho
Field circuit 39: scanning angle holding circuit 40: moving average calculation circuit 41: D / A converter 42: V / I converter

Claims (5)

【特許請求の範囲】[Claims] 【請求項1】 ライン上を搬送されている亜鉛メッキ鋼
板の合金化度を計測する方法において、亜鉛メッキ鋼板
の表面に光を照射するとともに、該照射光の位置を亜鉛
メッキ鋼板の搬送方向及び幅方向に面状に繰り返し走査
し、前記照射光の正反射方向の、亜鉛メッキ鋼板の表面
からそのパスライン変動に比べて充分に大きな距離を隔
てた位置に配置した受光器により、反射光の強度を実質
上連続的に検出し、少なくとも1回の面走査の中で検出
された反射光強度分布の最大値に基づいて、合金化度を
求めることを特徴とする、亜鉛メッキ鋼板の合金化度計
測方法。
1. A method for measuring the degree of alloying of a galvanized steel sheet conveyed on a line, wherein the surface of the galvanized steel sheet is irradiated with light, and the position of the irradiation light is set in the conveying direction of the galvanized steel sheet. Repeatedly scanning the surface in the width direction, in the direction of specular reflection of the irradiation light, by a light receiver arranged at a position sufficiently large distance from the surface of the galvanized steel sheet compared to the path line fluctuation, Alloying of galvanized steel sheet, characterized in that the intensity is detected substantially continuously and the degree of alloying is determined based on the maximum value of the reflected light intensity distribution detected in at least one surface scan. Degree measuring method.
【請求項2】 亜鉛メッキ鋼板の表面に照射する光を一
時的に遮断し、その時に前記受光器で検出された受光強
度を背景光レベルとし、少なくとも1回の面走査の中で
検出された反射光強度分布の最大値と前記背景光レベル
との差分に基づいて合金化度を求める、前記請求項1記
載の亜鉛メッキ鋼板の合金化度計測方法。
2. The light irradiated onto the surface of the galvanized steel sheet is temporarily blocked, and the received light intensity detected by the photodetector at that time is taken as the background light level, and the light is detected during at least one surface scan. The method for measuring the degree of alloying of a galvanized steel sheet according to claim 1, wherein the degree of alloying is obtained based on the difference between the maximum value of the reflected light intensity distribution and the background light level.
【請求項3】 亜鉛メッキ鋼板の表面に照射する光を一
時的に遮断し、その時に前記受光器で検出された受光強
度を背景光レベルとし、少なくとも1回の面走査の中で
検出された反射光強度分布の中での最大値が現われた位
置に応じて、該最大値に走査角度の補正を施し、補正さ
れた前記最大値と前記背景光レベルとの差分に基づいて
合金化度を求める、前記請求項1記載の亜鉛メッキ鋼板
の合金化度計測方法。
3. The light irradiated to the surface of the galvanized steel sheet is temporarily blocked, and the received light intensity detected by the photodetector at that time is used as the background light level, and the light is detected during at least one surface scan. Depending on the position where the maximum value appears in the reflected light intensity distribution, the scanning angle is corrected to the maximum value, and the alloying degree is determined based on the difference between the corrected maximum value and the background light level. The method for measuring the degree of alloying of a galvanized steel sheet according to claim 1, which is obtained.
【請求項4】 亜鉛メッキ鋼板の表面に照射する光を一
時的に遮断し、その時に前記受光器で検出された受光強
度を背景光レベルとし、1回の面走査の中で検出された
反射光強度分布の最大値と前記背景光レベルとの差分
を、複数回の面走査について平均化し、その結果に基づ
いて合金化度を求める、前記請求項1記載の亜鉛メッキ
鋼板の合金化度計測方法。
4. The reflection that is detected during one surface scan by temporarily blocking the light irradiating the surface of the galvanized steel sheet and setting the received light intensity detected by the photodetector at that time as the background light level. The alloying degree measurement of the galvanized steel sheet according to claim 1, wherein the difference between the maximum value of the light intensity distribution and the background light level is averaged over a plurality of surface scans, and the alloying degree is obtained based on the result. Method.
【請求項5】 亜鉛メッキ鋼板の表面に照射する光を一
時的に遮断し、その時に前記受光器で検出された受光強
度に対応する信号レベルを背景光レベルとし、該背景光
レベルに比例する一定の電流を前記受光器の信号を処理
する回路に注入し、該電流を少なくとも1回の面走査時
間保持する、前記請求項1記載の亜鉛メッキ鋼板の合金
化度計測方法。
5. The light irradiating the surface of the galvanized steel sheet is temporarily blocked, and the signal level corresponding to the received light intensity detected by the photodetector at that time is set as the background light level, and is proportional to the background light level. The method for measuring the degree of alloying of a galvanized steel sheet according to claim 1, wherein a constant current is injected into a circuit for processing a signal of the light receiver, and the current is held for at least one surface scanning time.
JP19863692A 1992-07-24 1992-07-24 Method of measuring alloying degree of galvanized steel sheet Expired - Lifetime JP2733416B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP19863692A JP2733416B2 (en) 1992-07-24 1992-07-24 Method of measuring alloying degree of galvanized steel sheet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP19863692A JP2733416B2 (en) 1992-07-24 1992-07-24 Method of measuring alloying degree of galvanized steel sheet

Publications (2)

Publication Number Publication Date
JPH0643097A true JPH0643097A (en) 1994-02-18
JP2733416B2 JP2733416B2 (en) 1998-03-30

Family

ID=16394506

Family Applications (1)

Application Number Title Priority Date Filing Date
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Country Status (1)

Country Link
JP (1) JP2733416B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10325755A (en) * 1997-01-22 1998-12-08 Nippon Steel Corp Spectroscopic analyzer and analytic method

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50120692A (en) * 1974-03-08 1975-09-22
JPS54103370A (en) * 1978-01-31 1979-08-14 Mitsubishi Electric Corp Dimension measuring apparatus
JPS5818103A (en) * 1981-07-27 1983-02-02 Kawasaki Steel Corp Shape measuring method for plane to be measured under environment with scattered substance
JPS58210550A (en) * 1982-06-01 1983-12-07 Nippon Steel Corp Deciding method of alloying degree of galvanized steel plate
JPS61105415A (en) * 1984-10-29 1986-05-23 Mitsubishi Electric Corp Distance measuring instrument
JPH03175342A (en) * 1989-12-04 1991-07-30 Sumitomo Metal Ind Ltd Method for measuring alloying degree of alloyed hot dip zinc plated steel plate
JPH03272885A (en) * 1990-03-22 1991-12-04 Hitachi Ltd Speck evaluation device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50120692A (en) * 1974-03-08 1975-09-22
JPS54103370A (en) * 1978-01-31 1979-08-14 Mitsubishi Electric Corp Dimension measuring apparatus
JPS5818103A (en) * 1981-07-27 1983-02-02 Kawasaki Steel Corp Shape measuring method for plane to be measured under environment with scattered substance
JPS58210550A (en) * 1982-06-01 1983-12-07 Nippon Steel Corp Deciding method of alloying degree of galvanized steel plate
JPS61105415A (en) * 1984-10-29 1986-05-23 Mitsubishi Electric Corp Distance measuring instrument
JPH03175342A (en) * 1989-12-04 1991-07-30 Sumitomo Metal Ind Ltd Method for measuring alloying degree of alloyed hot dip zinc plated steel plate
JPH03272885A (en) * 1990-03-22 1991-12-04 Hitachi Ltd Speck evaluation device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10325755A (en) * 1997-01-22 1998-12-08 Nippon Steel Corp Spectroscopic analyzer and analytic method

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