JP2004109068A - Movable metal material flaw type discrimination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small movable discrimination device for process control capable of executing a light emission analysis of a product flaw part/normal part to rapidly determine the flaw type from a specific constituent to the flaw type extracted by its strength rate and thereby contributing to clarification of the generation cause of the flaw without cutting the flaw part of a metal product such as a thin plate. <P>SOLUTION: This movable metal material flaw type discrimination device comprises a probe part 10 used for forming an inert atmosphere between the surface of a metal sample 1 and an electrode and for generating spark discharge to introduce an emission spectrum from the metal sample surface to an optical fiber 13 through a condenser lens 4; and a device body including a spectrograph 30 connected to the probe part 10 through the optical fiber 13 for executing a spectroscopic analysis of the emission spectrum, and a data processing part for executing arithmetic processing of information from the spectrograph 30. <P>COPYRIGHT: (C)2004,JPO

Description

【００４９】
なお表１中、記号◎および○は、
比強度＝（疵部の元素発光強度）／（正常部の元素発光強度）
とし、目安として◎：比強度＞３、○：比強度＞１．５と設定したものである。
【００５０】
本発明の検査装置は、圧延で製造され、表層に介在物、パウダー、スケール等に起因する疵が発生し易い金属薄板、金属厚板、棒鋼、線材等に対し特に有効なものであるが、基本的には電極と介在物、パウダーおよびスケールとの間に選択的放電が生じればその効果が得られるから、本発明にいう金属製品は特定の材質や組成の金属製品や特定の形態の金属製品に限定されない。
【００５１】
しかも、このように疵の原因箇所を迅速かつ的確に突き止めて不良製品の発生を最小限にすることが可能であるが、しかもその分析のために金属製品を分割したりサンプルを切り出す必要がないので、その点でも有利である。
【００５２】
【実施例】
次に本発明の実施例について説明するが、本発明は実施例で用いた諸条件に限定されるものではない。
【００５３】
以下の実施例では図１に示したような可動式スパーク発光分析装置を用いた。検出器３３としてはＣＣＤ（３０００ピクセル×１４チップ）を用いた。これを用いた分光器は、回折格子３０００／ｍｍ、波長範囲１８５〜４２０ｎｍで測定し、一次逆線分散は０．９ｎｍ／ｍｍ、分解能は０．００６ｎｍであった。これらの実施例では分光器内の空気を置換する必要はなかったが、図１の装置は空気をアルゴンガスなどに置換できる装置であり、測定対象の金属製品に応じてガスを置換できるものであった。
【００５４】
以下の実施例で用いた可動式スパーク発光分析装置は、プローブ部は長さ約３ｍの光ファイバーと放電部、光学レンズ等で構成され、所望の部分に動かし、分析することができる。また、装置本体は長さ約５００ｍｍ、奥行き約４５０ｍｍ、厚さ約２００ｍｍ、重量約２５ｋｇの分光部及び解析部とガスボンベを簡易カートに積載して構成されたもので、容易に可動できる小型装置であった。
（実施例１）
図１の装置を用い、図２の如くして、表層に介在物が存在する鋼板を用いて電圧３００Ｖ、周波数３３３Ｈｚ、スパーク放電、アルゴン雰囲気の条件で、鋼板上に存在する介在物の組成および形態、更に原因物質および発生箇所を特定した。
表１に疵の発光強度を示す。ここで、検出強度として用いる記号は、
比強度＝分析箇所元素の発光強度／基準元素の発光強度
を用い、目安として、◎：比強度＞３、○：比強度１．５と設定したものである。このとき、基準強度を測定し登録したものを用いる。
【００５５】
この実施例では、表２に示すように、特にＺｒが特異的に検出されているが、このことから疵は鋳造過程で用いるパウダーに起因するパウダー疵であると特定することができる。
【００５６】
【表２】

【００５７】
（実施例２）
図１の装置を用い、図２の如くして、表２に示した結果に基づいて原因物質および発生箇所に係る条件を調整して溶鋼を鋳造し圧延した。
【００５８】
解析結果よりこれまで使用していたパウダーＡは溶鋼に巻き込まれ易い性質のものであることが判明したので、パウダーＡを組成を変更したパウダーＢにかえて溶鋼を鋳造した。その結果を表３に示す。
【００５９】
【表３】

【００６０】
表３から、パウダーＡをパウダーＢに代えたことによりパウダー起因の疵の発生率を５．５％から３．４％に低減できたことが分かる。
【００６１】
（実施例３）
図１の装置を用い、図２の如くして、表層に疵が存在する鋼板を用いて、電圧３００Ｖ、周波数３３３Ｈｚ、アルゴン雰囲気下でのスパーク放電の条件で検査を行い、鋼板上に存在する疵の組成および原因物質と発生箇所を特定した。
【００６２】
図３は、疵が認められない正常部のＭｇスパーク放電発光強度分析の例を示す。２０００パルス全体にわたり、Ｍｇは殆ど含有されていないことが分かる。
【００６３】
図４は、疵部のＭｇスパーク放電発光強度分析の例を示す。放電初期より非常に高いパルス状ピークが出現し、２０００パルスまでかなりの大きさでＭｇが検出されていることが示されている。
【００６４】
図５は、図３および図４で示したように正常部と疵部を個別に分析し、その２０００パルスまでの強度比（疵部／正常部）をＦｅ，Ｃ，Ｓｉ，Ｍｎ，Ｐ，Ｓ，Ｔｉ，Ａｌ，Ｍｇ，Ｃａ，Ｚｒ，Ｎ元素で円グラフとして表示した例を示す。この図より疵部は正常部と比較して、Ｍｇが約１２倍、Ａｌ，Ｃａが約５倍含まれていることが明確に判別できる。
【００６５】
表１に示すスペクトル解析元素と原因物質推定表によると、この疵部を構成している元素は耐火物の主要構成元素であるＭｇ，Ａｌを含むため、検出された疵の原因物質は耐火物であること、また発生箇所は鋳造工程であることが判明した。
【００６６】
以上の結果を得るまでに要した時間は、分析２ケ所測定で、約１分程度で終了した。従来のレーザー照射分析法などではサンプル切り出しを含めて、約半日かかるのと比較すると、大幅な時間短縮ができ、作業効率の向上、品質向上に大きく役立つことができた。
【００６７】
【発明の効果】
こうして本発明のスパーク発光分析装置によれば下記のような効果が奏される。
（１）可動化効果：金属製品の製造現場でスパーク発光分析を行うことが可能になるので、従来のサンプル切り出し、移動が不要になる。また、問題が発生した場所など必要な場所にスパーク発光分析装置に運搬移動させて、なおかつ正確な分析をすることが可能になる。固定構造物の非破壊検査装置としても利用できる。
（２）迅速化効果：従来のサンプル切り出し、移動、レーザー発光分析などでは、少なくとも数時間かかっていたのを、疵発生箇所で、即座に分析するため、数分以内にまで短縮できる。
（３）搬送費用等低減効果：従来はサンプル切り出しのため、コイル分割により複数のコイルが発生し、その梱包費用、運送費用が複数個発生していたが、本発明によればコイルを分割することなく、その場分析できるので、そのような欠点を解消できる。
（４）コスト低減効果：迅速かつ的確な疵発生原因個所を特定できるため、疵発生から対策までの時間が短縮され、その間に発生する不良品の量を最小限に食い止めることができる。
【図面の簡単な説明】
【図１】本発明のスパーク発光分析装置の模式図である。
【図２】本発明のスパーク発光分析装置を用いた金属製品の検査方法を説明する図である。
【図３】疵が認められない正常部のＭｇスパーク放電発光強度分析の例を示す。
【図４】疵部のＭｇスパーク放電発光強度分析の例を示す。
【図５】Ｆｅ，Ｃ，Ｓｉ，Ｍｎ，Ｐ，Ｓ，Ｔｉ，Ａｌ，Ｍｇ，Ｃａ，Ｚｒ，Ｎ元素について正常部と疵部を個別に分析し、その強度比（疵部／正常部）を表示した円グラフである。
【符号の説明】
１…金属試料
２…不活性ガス放出手段
３…放電用電極
４…集光レンズ
１１…電線
１２…ガス管
１３…光ファイバ
１５…ガス容器
４１…測光装置
４２…演算処理装置
１０…プローブ部
２０…発光部
２１…放電制御装置
３０…分光部
３１…回折格子
３２…分光スペクトル
３３…検出器
４０…データ処理部
５１…ローラ
５２…金属板
５３…コイラー
５４…検定台
５５…スパーク発光分析装置[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a metal material flaw type discriminating apparatus, and in particular, can perform flaw type discrimination by spark emission analysis of a metal material at a manufacturing process site of a metal material or a metal product, and further for a steel structure. The present invention relates to a movable metal material flaw type discriminating apparatus capable of performing non-destructive flaw inspection.
[0002]
[Prior art]
The flaws generated on the metal surface in a metal product manufacturing process such as a steel plate manufacturing process are often caused by adhesion of inclusions or powder used for casting, entrapment, inclusion of refractories, entrainment of scale, and the like. Therefore, after finding a product flaw, it is necessary to quickly and accurately determine the cause by investigating the form and components thereof and remove the cause of the surface flaw.
[0003]
As an example of a flaw inspection device for that purpose, there is a method of identifying a flaw type by using a past learning and discrimination function of a detection signal obtained from an optical surface flaw detection means as a method of discriminating a steel sheet surface flaw (Japanese Patent Laid-Open No. 8-15178). Publication). However, since the information on the flaw components is lacking, it is difficult to specify the generation process even if the form is known.
[0004]
Therefore, in order to obtain information on the flaw component, a method of cutting out a sample from the metal product having the flaw and specifying the component by X-ray fluorescence analysis, observation with an electron microscope, or the like is used, but it took time for pretreatment and the like. .
[0005]
Therefore, as a method of analyzing and determining the cause of flaws on the surface of a steel material, a method of irradiating a flaw portion with a pulse laser to generate fine particles and easily and quickly obtaining a flaw component has been disclosed (JP-A-7-159299). However, due to the size of the equipment and the difficulty of collecting the laser irradiation and emission spectrum, the metal product (coil) is inevitably divided and the sample is cut out and measured in batches. And it took a long time from sample extraction to determination.
[0006]
[Problems to be solved by the invention]
In view of the above-mentioned problems of the prior art, the present invention performs an emission analysis of a product surface flaw / normal part without cutting a flaw of a metal product such as a thin plate, and is extracted based on its intensity ratio. It is an object of the present invention to provide a small-sized movable process control / determination apparatus that determines the type of surface flaw from a specific component for each location where the surface flaw is generated and contributes to elucidation of the cause of the surface flaw.
[0007]
[Means for Solving the Problems]
The inventor of the present invention has found that when a voltage is applied to a nonconductor material such as an inclusion contained in a conductor such as a metal, polarization occurs in a boundary region between the metal and the nonconductor, and a discharge occurs selectively at that portion. (Selective discharge phenomenon to inclusions) It is disclosed in Japanese Patent Application Laid-Open Publication No. Heisei 4- (1994) that by measuring and analyzing the emission spectrum, the number, diameter, content, or average diameter of inclusions can be determined according to a predetermined formula. 238250.
[0008]
As described above, by analyzing the emission spectrum related to the selective discharge, it is possible to obtain information related to the aspect and form of the inclusion, but the present inventor has continued the selective discharge to the inclusion appearing in the metal product. Then, it was found that the inclusions diffused finely, evaporated, and finally the inclusions disappeared in the metal surface layer, so if the emission spectrum was analyzed based on this finding, it would be possible to analyze the composition of the inclusions. We arrived at the idea and investigated the relationship between the emission spectrum and the composition of inclusions.
[0009]
As a result, the present inventors have proposed a flaw inspection method and apparatus for metal products and a flaw erasing method in Japanese Patent Application No. 2002-168840.
[0010]
According to the method for inspecting flaws of a metal product, the composition of inclusions can be almost specified, and similarly, the scale that causes surface flaws and the composition of powder used in the casting process can be almost specified. Further, the flaw inspection apparatus is an apparatus for performing the flaw inspection method, and includes a discharge light emission analysis apparatus and an inert gas supply apparatus for forming an inert gas atmosphere between a metal product surface layer and an electrode. Yes, flaw inspection of metal products is performed on the production line.
[0011]
However, although the disclosure of the above application is not limited, the specific disclosed flaw inspection apparatus employs a configuration in which the spectroscope is installed integrally with the condenser lens, so there is a limit to the decomposition of the emission spectrum. Was. This is based on the premise that high resolution is not required by limiting the elements that specify the flaw-causing substances such as casting powder, inclusions, and refractories to specific metals such as Mg, Al, Ti, and Zr. Met.
[0012]
However, it may be desirable for a metal product flaw inspection device to have higher spectral resolution. Although the spectral resolution of a conventionally known spark discharge optical emission spectrometer is very high, as described above, it was necessary to cut out a sample from a metal product due to the size of the device configuration and the like.
[0013]
Therefore, the present inventor, without separating the metal product to be inspected from the base material, immediately analyzes the flaw component at the flaw occurrence site even in a place other than the production line, and automatically specifies the cause of the flaw from the result. With this in mind, a study was conducted with the aim of developing a movable spark discharge optical emission spectrometer capable of having a high spectral resolution and being movable.
[0014]
The present inventor has found that the reason why the conventional high-performance spark discharge optical emission spectrometer is of a stationary type is that, in particular, the spectroscopic section needs to be a vacuum chamber in order to prevent light absorption by oxygen in a short wavelength region, and furthermore, the spectral intensity is reduced. As a result of using a photomultiplier tube as a detector for multiplication, the size of the photomultiplier was inevitably increased, and it became a stationary type. The present inventors have succeeded in developing a small-sized emission spectrometer capable of analyzing components and automatically specifying the cause of a flaw, and completed the present invention. Thus, the present invention that achieves the above object is as follows.
[0015]
(1) (a) means for forming an inert gas atmosphere between the metal sample surface layer and the electrode;
(B) an electrode for generating a spark discharge between itself and the surface of the metal sample, and a condenser lens for condensing an emission spectrum from the surface of the metal sample due to the discharge, wherein the condenser lens is connected to an optical fiber. A probe unit, wherein the probe unit is a movable unit;
(C) an optical fiber connecting the probe unit and a later-described spectral unit,
(D) a discharge control unit that controls the spark discharge electrically connected to the electrode of the probe unit;
(E) a spectroscopy unit that decomposes the emission spectrum guided by the optical fiber from the probe unit via a diffraction grating and receives the spectrum with a detector;
(F) a data processing unit including a photometric device that converts an emission spectrum signal from the spectroscopic unit into an electric signal, and a spectrum analysis operation device that analyzes the signal and specifies the composition and / or form of a surface flaw. Discharge emission analysis section
A metal material flaw type discriminating apparatus characterized by comprising:
[0016]
(2) The metal material flaw type discriminating apparatus according to (1), wherein the discharge control unit, the spectroscopic unit, and the discharge light emission analyzing unit form a device main body and are movable.
[0017]
(3) The metal material flaw type discriminating apparatus according to (1) or (2), wherein the spectroscopic unit does not include a vacuum chamber.
[0018]
(4) The metal material flaw classification according to any one of (1) to (3), wherein the spectroscopic unit is configured to spectrally decompose by a diffraction grating and receive light by a detector, and is capable of replacing an atmospheric gas between the diffraction grating and the detector. Discriminator.
[0019]
(5) The metal material flaw type discriminating apparatus according to any one of (1) to (4), wherein the detector is a CCD.
[0020]
(6) The discharge control unit, the spectroscopy unit, and the discharge emission analysis unit integrally constitute a device main body, the device main body and the probe unit are connected by an optical fiber, and the device main body is also movable. The metal material flaw classification apparatus according to any one of (1) to (5).
[0021]
(7) The inert gas supply means is connected to an inert gas container installed in the apparatus main body via a gas conduit, and the gas conduit connects the optical fiber between the apparatus main body and the probe section. The metal material flaw type discriminating apparatus according to any one of (1) to (6) above.
[0022]
(8) The metal material flaw type according to any one of (1) to (7), wherein the surface flaw is caused by one or more of inclusions, powder used in a casting process, and scale. Discriminator.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
This will be described with reference to the drawings.
[0024]
Spark discharge emission spectroscopy is known (eg, Agne "Latest Steel Condition Analysis", 1979, p. 112). When a pulse voltage is applied from the electrode facing the surface of the metal sample with a spark discharge emission analyzer, a spark discharge occurs in inclusions and the like and the metal part dispersed in the metal sample, and the wavelength and intensity of the discharge emission and the intensity of the discharge. The content of inclusions and the like and the soluble substance are determined for each form from the number of times.
[0025]
In the present invention, a metal sample means a metal material to be evaluated, and is intended to analyze a metal material in a manufacturing process on site, but may be a material sampled for evaluation from the manufacturing process. . The metal material is not particularly limited, such as steel, aluminum, copper, titanium, and stainless steel.
[0026]
Inclusions and the like in a metal sample are non-metallic inclusions unintentionally and undesirably mixed in from a raw material or a manufacturing process, and non-metallic precipitates intentionally deposited for the purpose of modifying a metal material. Non-metallic inclusions include oxides formed by oxidizing metal elements (such as aluminum and titanium in steel) added in the refining process, and non-metallic precipitates include, for example, aluminum nitride in steel. , Titanium carbide and niobium carbide. In the present specification, these are collectively referred to simply as inclusions and the like, but such inclusions and the like are different from elements dissolved in a metal base material and have a size from an extremely fine to a certain size. It exists with a distribution up to the particles.
[0027]
Referring to FIG. 1, near a surface of a metal sample 1, an inert gas releasing means 2, a probe unit 10 including a discharge electrode 3 and a condenser lens 4 are present.
[0028]
The inert gas releasing means 2 (at the end of the gas pipe 12) is connected to the inert gas container 15 of the main body of the analyzer via the gas pipe 12, and makes the discharge location an inert atmosphere during discharge. The inert gas atmosphere forming device is not limited to such a configuration as long as it can supply an inert gas to a discharge location. The inert gas discharging means 2 connected to the inert gas container and forming the inert atmosphere forming means may be configured as a part of the probe unit 10 including the discharge electrode 3 and the condenser lens 4. Alternatively, it may be configured separately from the probe unit.
[0029]
The probe unit 10 includes at least the discharge electrode 3 and the condenser lens 4. The discharge electrode 3 is electrically connected to a discharge control device 21 provided in the light emitting section 20 of the analyzer main body. The condenser lens 4 is connected to the spectroscope 31 of the spectroscopy unit 30 via the optical fiber 13. Although the gas pipe 12 and the optical fiber 13 are illustrated separately in FIG. 1, it is preferable in terms of handling that, in practice, they be integrated into a single unit including the electric wiring (broken line 11) from the discharge control device 21.
[0030]
In a conventional spark emission analyzer, spark emission generated by discharge is analyzed by a spectroscope including a photomultiplier tube connected to a vacuum chamber. In the present invention, the probe unit 10 is provided, where spark light is emitted, collected by the condenser lens 4, and the light is guided by the optical fiber 13 and sent to the spectroscopic unit 30 of the analyzer main body. Is designed to reduce the size of the detector 33 using a CCD or the like, and then to perform a spectral analysis of spark emission. In order to make the metal material flaw type discriminating device mobile (movable) while maintaining high sensitivity, it is necessary to separate the spectroscopic device main body and the light collecting portion (probe portion) using the optical fiber 13. . Accordingly, in the present invention, it is only necessary to dispose the probe section 10 including an inert gas supply unit, a discharge electrode, a lens for condensing spark emission, and other optical systems in the vicinity of the sample of the metal product. Such a probe portion is lightweight and movable, and can be adapted to directly inspect metal products in the manufacturing process.
[0031]
Further, conventionally, in order to analyze light elements such as C, P, and S with high sensitivity, the spark emission analyzer conventionally evacuates the spectroscopic section 30 to prevent absorption by oxygen and efficiently multiplies the spectral sensitivity. Since a photomultiplier tube (phototube; photomultiplier) is used for the detector 33, the apparatus is inevitably increased in size and is of a stationary type. The present invention aims at inspecting a metal product in a manufacturing process of the metal product on site, so that the size is reduced by eliminating the evacuation that causes the device to become large. Even if the evacuation is eliminated, if necessary, the atmosphere in the spectroscopic section (between the spectroscopic means 31 and the light receiving detector 33) can be replaced with another element (nitrogen, argon, etc.) to prevent oxygen absorption. Accordingly, the sensitivity to the target element can be increased accordingly. Further, desirably, in the spectroscopic unit 30, the spectrum 32 obtained by spectral decomposition from the spectroscope 31 is received by a small detector 33 such as a CCD (charge coupled device). A major reason why the metal material flaw classification device of the present invention can be made mobile (movable) is the elimination of evacuation. In particular, the reason why the apparatus main body can be made movable is to eliminate the evacuation.
[0032]
Note that the discharge electrode 3 and the discharge control device 21 may have known configurations. It is easy to use a metal sample as the other electrode.
[0033]
The light condensed by the condensing lens 4 may be directly guided by the optical fiber 13 to a spectroscopic unit 31 such as a diffraction grating of the spectroscopic unit 30. The spark emission guided by the optical fiber 13 to the spectral unit 30 is decomposed into a spectral spectrum 32 by a diffraction grating 31 and then detected by a detector 33. As the detector 33 of the spectrum 32, a photomultiplier tube can be used as in the related art, but in a preferred embodiment of the present invention, a CCD or the like is used as the detector. The photomultiplier tube has a disadvantage that it is weak in vibration, but the CCD is strong in vibration, so that it can be stably measured even in the field. Further, by using a CCD, the spectrometer can be downsized. In addition, since the CCD can simultaneously measure not only the target spectrum but also the wavelength in the vicinity thereof, it has a feature that the wavelength can be easily calibrated based on the reference spectral line of the iron matrix even when measuring at a site where the temperature changes rapidly. The miniaturization of the spectroscopic device and the response to vibration have the effect of reducing the size of the entire device of the present invention in addition to the elimination of the vacuum chamber. Not only the above-described probe unit, but also the light emitting unit 20, the spectroscopic unit 30, and the data processing unit 40 It is possible to make the spark emission analyzer main body including the above movable. If the CCD is used as a detector, it is easy to determine the cause of the flaw of the metal material from the result of spark emission analysis in the data processing unit 40 using the electric signal. One major factor in making the metal material flaw type discriminating apparatus compact and movable while maintaining high sensitivity is the use of a detector such as a CCD.
[0034]
As the CCD used in the present invention, for example, a CCD having a chip of 120 to 3000 pixels to 1 to several tens of chips and capable of measuring ultraviolet, visible, and infrared light regions is used.
[0035]
The data processing unit 40 includes a photometric device 41 for measuring information from the detector 33 and an arithmetic processing device 42 for calculating data obtained therefrom. In addition, although the spark emission analysis technology itself of the metal material is known and does not require explanation, in the present invention, the spark emission analysis device is made mobile to perform a quick and accurate inspection of flaws at the site of a metal product, A technique for locating the cause of the flaw is provided, and the data processing unit 40 is used for that purpose. This will be described later.
[0036]
In a typical example, a conventional spark emission analyzer using an electron multiplier (phototube) has a size of about 1500 mm, a depth of about 1000 mm, a height of 1500 mm, and a weight of about 500 kg. According to the invention, by adopting a spectroscopic method using a CCD excluding a vacuum chamber, even if the spectroscopic unit and the analyzing unit are included, for example, the length is about 500 mm, the depth is about 450 mm, the thickness is about 200 mm, and the weight is 25 kg. And can be easily moved with a simple cart.
[0037]
A power source can be incorporated in the main body of the apparatus as needed, thereby improving mobility (movability).
[0038]
As described above, in the spark emission analysis apparatus of the present invention, only the probe section 10 including the inert gas supply means 2, the discharge electrode 3, and the condenser lens 4 needs to be close to the metal product as the test sample. It has a feature that a metal product can be directly subjected to spark emission spectrometry inspection at the site of a metal product manufacturing process without having to cut a sample from the metal product in the metal product manufacturing process. Therefore, for example, since it is not necessary to divide the coil and take a sample in order to perform an inspection in the manufacture of a steel sheet coil, the coil unit can have a desired size. In addition, there is an advantage that it is possible to suppress an increase in the cost of packing and transporting the coil due to the multiple division.
[0039]
In addition, the spark emission analyzer of the present invention reduces the size of the spectroscopic unit by eliminating not only the probe unit 10 but also a vacuum chamber from the spectroscopic unit, so that the light emitting unit 20, the spectroscopic unit 30, and the data processing unit 40 Since the spark emission analyzer main body including the above is also made movable, it can be moved to a target inspection location and used. For example, it is also possible to perform a nondestructive flaw inspection on a steel structure. Moreover, the movable spark emission analyzer of the present invention is miniaturized and movable by connecting the optical fiber 13 between the probe unit 10 including the light emitting unit and the device main unit including the spectroscopic unit 30 and separating the light by the device main unit. However, it has the feature that it is possible to achieve high-sensitivity spectral analysis in the main body of the apparatus.
[0040]
FIG. 2 shows a state of inspection of a metal plate using the spark emission analyzer of the present invention. The metal plate 52 conveyed via the various rollers 51 is finally formed into a coil by a coiler 53, and is used on the way when passing over a test stand 54 using a spark emission analyzer 55 of the present invention. Emission analysis is performed. The metal plate 52 can be electrically connected or contacted via a test stand 54 or another member connected to the discharge control device 21 to constitute another discharge electrode.
[0041]
The spark emission spectrometer of the present invention has been developed mainly for the purpose of inspecting a steel sheet in a steel sheet manufacturing process. The reason why a surface flaw occurrence position can be specified based on the composition and / or form of the surface flaw is described. Will be described.
[0042]
The surface flaw is generated, for example, in a casting process by a refractory mixed in molten steel, inclusions floating on the surface of molten steel, or casting powder adhered to the surface of the slab or caught in the slab.
[0043]
Since the refractory is mainly composed of MgO, if the spectrum analysis reveals that the main component of the surface flaws remaining on the metal surface layer is Mg, the surface flaw is caused by the refractory. Therefore, the location where the surface flaw is generated can be specified to be in the process of casting molten steel, and the cause of the inclusion of the refractory itself can be presumed to be a process before casting.
[0044]
Further, since the inclusions floating on the surface of the molten steel are composed of oxides of Al, Ti and / or Si, if these elements are detected by the spectrum analysis, the inclusions remaining on the metal surface layer will be of the molten steel. It can be elucidated that it occurred during the casting process.
[0045]
If a trace amount of a specific element (for example, Zr) is mixed into the powder used in the casting process as a tracer, whether the surface flaw is caused by the powder or not, that is, whether the surface flaw is generated in the process of casting the molten steel or not. Can be determined.
[0046]
If the surface flaws penetrate into the metal surface layer without exfoliating the scale in the processing step after casting, by detecting the spectrum derived from FeO, which is the main component of the scale, the step of generating the surface flaws is performed in the hot working step. I can figure out something.
[0047]
Table 1 shows a typical relationship between the process of generating surface flaws and main component elements. Of course, a plurality of elements may be detected. In such a case, the causative substance can be specified by referring to the intensity ratio of the spectrum.
[0048]
[Table 1]

[0049]
In Table 1, symbols ◎ and ○ indicate
Specific intensity = (element emission intensity of flaw) / (element emission intensity of normal part)
And 目: specific intensity> 3, and ：: specific intensity> 1.5.
[0050]
The inspection device of the present invention is manufactured by rolling, and is particularly effective for thin metal sheets, metal thick plates, steel bars, wire rods, and the like, in which the surface layer is susceptible to flaws caused by inclusions, powder, scale, and the like, Basically, the effect can be obtained if a selective discharge occurs between the electrode and the inclusion, the powder and the scale, so that the metal product according to the present invention is a metal product of a specific material or composition or a specific form of the metal product. It is not limited to metal products.
[0051]
In addition, it is possible to quickly and accurately determine the location of the flaw to minimize the occurrence of defective products, but it is not necessary to divide metal products or cut out samples for the analysis. Therefore, it is also advantageous in that respect.
[0052]
【Example】
Next, examples of the present invention will be described, but the present invention is not limited to the conditions used in the examples.
[0053]
In the following examples, a movable spark emission analyzer as shown in FIG. 1 was used. As the detector 33, a CCD (3000 pixels × 14 chips) was used. The spectrometer using this was measured at a diffraction grating of 3000 / mm in a wavelength range of 185 to 420 nm, the primary inverse linear dispersion was 0.9 nm / mm, and the resolution was 0.006 nm. Although it was not necessary to replace the air in the spectrometer in these examples, the apparatus of FIG. 1 is an apparatus that can replace air with argon gas or the like, and can replace the gas according to the metal product to be measured. there were.
[0054]
In the movable spark emission analyzer used in the following examples, the probe unit is composed of an optical fiber having a length of about 3 m, a discharge unit, an optical lens, and the like, and can be moved to a desired portion for analysis. The main body is about 500mm in length, about 450mm in depth, about 200mm in thickness, and about 25kg in weight. there were.
(Example 1)
Using the apparatus of FIG. 1, as shown in FIG. 2, using a steel sheet having inclusions in the surface layer, under the conditions of a voltage of 300 V, a frequency of 333 Hz, a spark discharge, and an argon atmosphere, the composition of the inclusions existing on the steel sheet and The morphology, the causative substance and the place of occurrence were identified.
Table 1 shows the light emission intensity of the flaw. Here, the symbol used as the detection intensity is
Specific intensity = luminescence intensity of analysis element / luminescence intensity of reference element
And ：: specific intensity> 3, and ：: specific intensity 1.5 as a guide. At this time, the reference intensity measured and registered is used.
[0055]
In this example, as shown in Table 2, particularly Zr was specifically detected. From this, the flaw can be identified as a powder flaw caused by the powder used in the casting process.
[0056]
[Table 2]

[0057]
(Example 2)
As shown in FIG. 2, molten steel was cast and rolled using the apparatus shown in FIG. 1 while adjusting the conditions relating to the causative substance and the location of occurrence based on the results shown in Table 2.
[0058]
From the analysis results, it has been found that the powder A used so far has a property of being easily entangled in the molten steel. Therefore, the molten steel was cast by replacing the powder A with the powder B having a changed composition. Table 3 shows the results.
[0059]
[Table 3]

[0060]
From Table 3, it can be seen that the occurrence rate of powder-induced flaws was reduced from 5.5% to 3.4% by replacing Powder A with Powder B.
[0061]
(Example 3)
Using the apparatus shown in FIG. 1 and using a steel sheet having a flaw on the surface layer as shown in FIG. 2, an inspection is performed under the conditions of a voltage of 300 V, a frequency of 333 Hz, and a spark discharge in an argon atmosphere. The composition of the flaw, the causative substance and the place of occurrence were identified.
[0062]
FIG. 3 shows an example of Mg spark discharge emission intensity analysis of a normal part where no flaw is observed. It can be seen that almost no Mg is contained over 2000 pulses.
[0063]
FIG. 4 shows an example of Mg spark discharge emission intensity analysis of a flaw. A very high pulse-like peak appears from the beginning of the discharge, indicating that Mg is detected in a considerable size up to 2000 pulses.
[0064]
FIG. 5 shows that the normal part and the flaw part were separately analyzed as shown in FIGS. 3 and 4, and the intensity ratio (flaw part / normal part) up to 2000 pulses was Fe, C, Si, Mn, P, An example in which the elements S, Ti, Al, Mg, Ca, Zr, and N are displayed as a pie chart is shown. From this figure, it can be clearly determined that the flaw contains about 12 times Mg and about 5 times Al and Ca as compared with the normal part.
[0065]
According to the spectrum analysis elements and causative substance estimation table shown in Table 1, the elements constituting the flaw include Mg and Al, which are the main constituent elements of the refractory, so that the causative substance of the detected flaw is refractory. And the location of occurrence was found to be a casting process.
[0066]
The time required to obtain the above results was about one minute in two analysis measurements. Compared to the conventional laser irradiation analysis method, which takes about half a day including sample cutting, it can save a lot of time, greatly improving work efficiency and quality.
[0067]
【The invention's effect】
Thus, according to the spark emission analyzer of the present invention, the following effects can be obtained.
(1) Mobilizing effect: Spark emission analysis can be performed at a metal product manufacturing site, so that conventional sample cutting and moving are not required. In addition, it is possible to carry and move the spark emission analyzer to a necessary place such as a place where a problem occurs, and to perform accurate analysis. It can also be used as a non-destructive inspection device for fixed structures.
(2) Speeding-up effect: In the conventional sample cutting, moving, laser emission analysis, etc., it took at least several hours, but since it is immediately analyzed at the spot where the flaw occurs, it can be reduced to within several minutes.
(3) Reduction effect of transportation cost, etc .: Conventionally, a plurality of coils are generated by coil division for sample cutting, and a plurality of packing costs and transportation costs are generated. According to the present invention, the coil is divided. Since such analysis can be performed on the spot without any problem, such disadvantages can be solved.
(4) Cost reduction effect: Since the cause of the flaw occurrence can be specified quickly and accurately, the time from the occurrence of the flaw to the countermeasure can be shortened, and the amount of defective products generated during that time can be minimized.
[Brief description of the drawings]
FIG. 1 is a schematic view of a spark emission analyzer of the present invention.
FIG. 2 is a diagram illustrating a method for inspecting a metal product using the spark emission analyzer of the present invention.
FIG. 3 shows an example of Mg spark discharge emission intensity analysis of a normal part where no flaw is observed.
FIG. 4 shows an example of Mg spark discharge emission intensity analysis of a flaw.
FIG. 5: Normal parts and flaw parts are separately analyzed for Fe, C, Si, Mn, P, S, Ti, Al, Mg, Ca, Zr and N elements, and the intensity ratio (flaw part / normal part) Is a pie chart displaying.
[Explanation of symbols]
1: Metal sample
2. Inert gas release means
3. Discharge electrode
4: Condensing lens
11 ... electric wire
12 ... Gas pipe
13 ... Optical fiber
15 ... Gas container
41 Photometric device
42 ... arithmetic processing unit
10. Probe section
20 ... Light emitting unit
21 ... Discharge control device
30 ... Spectroscopy unit
31 ... Diffraction grating
32 ... Spectral spectrum
33 Detector
40 ... Data processing unit
51 ... roller
52 metal plate
53 ... Coiler
54 ... Test stand
55 ... Spark emission spectrometer

Claims (8)

(A) means for forming an inert gas atmosphere between the metal sample surface layer and the electrode;
(B) an electrode for generating a spark discharge between the surface of the metal sample and a condenser lens for condensing an emission spectrum from the surface of the metal sample due to the discharge, wherein the condenser lens is connected to an optical fiber; A probe part, wherein the probe part is a movable part,
(C) an optical fiber connecting the probe unit and a later-described spectral unit,
(D) a discharge control unit that controls the spark discharge electrically connected to the electrode of the probe unit;
(E) spectrally decomposing the emission spectrum guided by the optical fiber from the probe section via a diffraction grating, and receiving the light by a detector; and (f) converting the emission spectrum signal from the spectrum section into an electric signal. A metal material, comprising: a photometric device that converts the data into a laser beam; and a discharge light emission analysis unit that includes a data processing unit that includes a spectrum analysis operation device that analyzes the signal to specify the composition and / or morphology of the surface flaw. Defect type discrimination device. The metal material flaw classification apparatus according to claim 1, wherein the discharge control unit, the spectroscopic unit, and the discharge light emission analysis unit form a device main body and are movable. The apparatus according to claim 1, wherein the spectroscopic unit does not include a vacuum chamber. 4. The metal material defect type discriminating apparatus according to claim 1, wherein the spectroscopic unit is configured to decompose a spectrum by a diffraction grating and receive light by a detector, and to replace an atmosphere gas between the diffraction grating and the detector. The metal material flaw classification apparatus according to any one of claims 1 to 4, wherein the detector is a CCD. The said discharge control part, the said spectroscopy part, and the said discharge light emission analysis part integrally comprise an apparatus main body, The said apparatus main body and the said probe part are connected with an optical fiber, The said apparatus main body is also a movable type. The metal material flaw classification device according to any one of the above. The inert gas supply means is connected to an inert gas container installed in the apparatus main body via a gas conduit, and the gas conduit is provided between the apparatus main body and the probe section along with the optical fiber. The metal material flaw classification device according to any one of claims 1 to 6. The metal material flaw classification according to any one of claims 1 to 7, wherein the surface flaw is caused by one or more of inclusions, powder used in a casting process, and scale. apparatus.

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