JPS60152938A - Defect extracting method in magnetic particle inspection - Google Patents

Abstract

PURPOSE:To make it possible to perform automatic judgment of the defect in a sample body, by changing the magnetic particle pattern of the defect in the sample body by using a moving magnetic field, picking up the image of the pattern by an ITV camera, processing the output by a picture processing device, and extracting the defect. CONSTITUTION:In an MT inspection, excitation by a magnetic-particle flaw detector 6 and magnetic particle distribution 7 are performed for a sample body 1. The unnecessary magnetic particles are removed by air blowing 8. Then, the pattern of the remaining magnetic particles of a defect 3 is observed by an ITV camera 9 and lamps 10. The sample body 1 is excited by a rotary magnetic field type magnetic-particle flaw detector in three directions A(0 deg.), B(45 deg.) and C(90 deg.). Based on the position signal from a magnetic-pole movement controller 21, the pictures of the surfaces to be inspected for the directions A-C picked up by the ITV camera 9 are recorded in picture memories 19-19'' in a picture processing device 18. Operation and judgment are performed and a defect signal 22 is outputted. Thus, the defect and the harmful pseudo-defect are discriminated, and the sample body can be automatically judged.

Description

【発明の詳細な説明】 本発明は磁粉探傷検査における欠陥抽出法に関する。[Detailed description of the invention] The present invention relates to a defect extraction method in magnetic particle inspection.

例えば第１図（４）、（Ｂ）に示すように、磁粉探傷検
査（以下ＭＴ検査）における検査対象は、試験体１のよ
うな溶接部２を有するものが主流となる。このような検
査対象では、溶接部２の境界に欠陥３が発生することが
多い。一般的に溶接部２の近傍はアンダーカット４、ス
パッタ５尋が加工上桟ることが常であシ、ＭＴ検査では
欠陥３とアンダーカット４、スパッタ５等との識別がな
される必要がある。For example, as shown in FIGS. 1(4) and 1(B), the main objects to be inspected in magnetic particle inspection (hereinafter referred to as MT inspection) are those having a welded part 2, such as the test specimen 1. In such inspection objects, defects 3 often occur at the boundaries of the welded portions 2. In general, undercuts 4 and spatters 5 are often present in the vicinity of the weld 2 during processing, and in MT inspection it is necessary to distinguish between defects 3, undercuts 4, spatters 5, etc. .

第２図（４）、但）に示すように、ＭＴ検査の自動化を
図る要求から試験体１のＭＴ検査において第２図（４）
に示す如く磁粉探傷器６による励磁と同時に磁粉散布７
を行い、エアーブロア８で不要磁粉除去を行ったのち第
２図（Ｂ）に示す如く残る欠陥３の磁粉模様をＩＴＶカ
メラ９と照明１０によって観察し、自動識別の可能性が
検討されてきた。しかし、第３図（Ａ）　、　（Ｂ）に
示すように、試験体１におけるＩＴＶカメラ走査信号１
１．１２．１３の各部位ではそれぞれ１１′。As shown in Figure 2 (4), however, due to the demand for automation of MT inspection, in the MT inspection of test specimen 1, as shown in Figure 2 (4).
As shown in the figure, the magnetic particle scattering 7
After removing unnecessary magnetic particles with an air blower 8, the magnetic particle pattern of the remaining defect 3 is observed using an ITV camera 9 and an illumination 10 as shown in FIG. 2(B), and the possibility of automatic identification has been studied. However, as shown in FIGS. 3(A) and 3(B), the ITV camera scanning signal 1 on the test object 1
11' for each part of 1.12.13.

１２’、１３’の映像信号となシ、アンダーカット４、
スパッタ５等と混在した欠陥３の磁粉模様は識別困難で
あシ、自動判別化の見込みは極めて少ないとされてきた
。12', 13' video signal and undercut 4,
The magnetic particle pattern of the defect 3 mixed with the spatter 5 etc. is difficult to distinguish, and it has been said that there is very little prospect of automatic discrimination.

本発明は上記の事情に鑑みて提案されたもので、その目
的とするところは、欠陥と有害な擬似欠陥とを識別する
ことができ、熟練検査員による肉眼目視検査の領域を低
減し目視検査の自勧化を図シ得るＭＴ検査における欠陥
抽出法を提供するにある。The present invention was proposed in view of the above circumstances, and its purpose is to be able to distinguish between defects and harmful pseudo-defects, to reduce the area of visual inspection by skilled inspectors, and to reduce the area of visual inspection by skilled inspectors. An object of the present invention is to provide a defect extraction method in MT inspection that facilitates self-improvement.

本発明によ２ＭＴ検査における欠陥抽出法は、ＭＴ検査
において、移動磁界を用いて試験体の欠陥の磁粉模様を
変化させ、これをＩＴＶカメラによって撮像し、その出
力を画像処理装置によシ画像処理して前記磁粉模様の変
化を検出して前記試験体の欠陥を抽出することを特徴と
し、擬似欠陥であるアンダーカット、スパッタ等は、有
害な欠陥を内在しないかぎシ励磁による磁粉模様が発生
しないが、欠陥と有害な擬似欠陥とは励磁方向によって
磁粉模様の発生形態（残留磁粉量）が異なることを利用
し、この磁粉模様の変化をとらえることにより欠陥の識
別を行なうものであシ、そのため磁極移動によって励磁
方向を変化させ、その変化によって変わる磁粉模様をＩ
ＴＶカメラによシ撮像し、これを画像処理して任意励磁
方向毎に比較演算することによυ、試験体の目視検査を
自動化できるようにしたものである。The defect extraction method in 2MT inspection according to the present invention is such that in MT inspection, a moving magnetic field is used to change the magnetic particle pattern of defects on a test object, this is imaged by an ITV camera, and the output is converted into an image by an image processing device. The method is characterized in that defects in the test specimen are extracted by processing and detecting changes in the magnetic particle pattern, and false defects such as undercuts and spatters are caused by magnetic particle patterns caused by hook excitation that do not contain any harmful defects. However, defects and harmful pseudo-defects are distinguished by taking advantage of the fact that the generation form of magnetic particle patterns (residual magnetic particle amount) differs depending on the excitation direction, and by capturing changes in this magnetic particle pattern. Therefore, by changing the excitation direction by moving the magnetic pole, the magnetic particle pattern that changes depending on the change is
By capturing images with a TV camera, processing the images, and performing comparison calculations for each arbitrary excitation direction, visual inspection of the test specimen can be automated.

本発明の一実施例を添付図面を参照して詳細に説明する
。An embodiment of the present invention will be described in detail with reference to the accompanying drawings.

第４図は本発明方法を実施するために用いられる装置の
一実施例を示す図、第５図は第４図に示す一実施例の励
磁方向と欠陥の関係を示す図、第６図は第４図における
ゲ陥抽出法を説明するだめの図である。FIG. 4 is a diagram showing an embodiment of the apparatus used to carry out the method of the present invention, FIG. 5 is a diagram showing the relationship between the excitation direction and defects in the embodiment shown in FIG. 4, and FIG. 5 is a diagram for explaining the defect extraction method in FIG. 4. FIG.

第４図において、１は試験体、９はＩＴＶカメラ、１７
はカメラコントロールユニット、１８は画像処理装置、
１９．１９’、１９″は各画像メモリ、２０は演算部、
２１は磁極移動制御器、２２は欠陥信号である。In Fig. 4, 1 is the test object, 9 is the ITV camera, 17
is a camera control unit, 18 is an image processing device,
19. 19', 19'' are each image memory, 20 is a calculation unit,
21 is a magnetic pole movement controller, and 22 is a defect signal.

上記本発明の一実施例の作用について説明するＯ 第４図において、試験体１に対してＡ方向（０°）、Ｂ
方向（４５°）、Ｃ方向（９０°）の励磁を行う移動磁
界例えば回転磁界形磁粉探傷器を使用し、磁極移動制御
器２１の位置信号をもとにＩＴＶカメラ９に撮像される
Ａ−Ｃ方向毎の被検面画像をカメラコントロールユニッ
ト１７を介して画像処理装置１８内の各画像メモリ１９
〜１９″に記録してゆくｏ演算部２０は画像演算ならび
に論理判定を行うユニットで欠陥を識別して欠陥信号２
２を出力するものである。ここでＭＴ検査は、前記第２
図に示した要領で行える構成が必要であり、それらに、
第４図に示すものが加えられることによシ欠陥の自動判
定が可能となるものであるＯＭＴ検査において励磁方向
と欠陥の関係を示すメ第５図において、１４は溶接部２
に対して直交した欠陥を有する場合のもので、１５は平
行した欠陥を有する場合、１６は溶接境界等に発生した
欠陥を有する場合を示している。Ａ、Ｂ、Ｃに示す各励
磁方向毎の磁粉模様の発生時の残留磁粉量唸第５図中に
示す通りである。即ち、第６図に示すように、１４の試
験体例の場合（：は、１４′の入方向（０°）では、欠
陥部磁粉模様の発生はなく、１４”のＢ方向（４５°　
）では、中程度の磁粉残留が発生する。Ｊ２！ｌ二１４
“′のＣ方向（９０’）では、磁粉残留が著しく多い。The operation of the embodiment of the present invention will be explained. In FIG. 4, the direction A (0°) and the direction B
A- is imaged by the ITV camera 9 based on the position signal of the magnetic pole movement controller 21 using a moving magnetic field for excitation in the C direction (45°) and the C direction (90°), for example, using a rotating magnetic field type magnetic particle flaw detector. Images of the inspection surface for each C direction are sent to each image memory 19 in the image processing device 18 via the camera control unit 17.
~19'' The arithmetic unit 20 is a unit that performs image calculations and logical judgments, and identifies defects and generates a defect signal 2.
2. Here, the MT test includes the second
A configuration that can be performed in the manner shown in the figure is required, and
By adding the elements shown in Fig. 4, it becomes possible to automatically judge defects.
15 is a case in which a defect is perpendicular to the surface, 15 is a case in which a defect is parallel to the defect, and 16 is a case in which a defect occurs at a welding boundary or the like. The amount of residual magnetic particles when the magnetic particle patterns are generated in each excitation direction shown in A, B, and C is as shown in FIG. That is, as shown in Fig. 6, in the case of 14 test specimens (: means 14' in the direction of entry (0°), there is no defective magnetic particle pattern, and in the B direction of 14'' (45°)
), a moderate amount of residual magnetic particles will occur. J2! l214
In the C direction (90') of "', there are significantly more magnetic particles remaining.

従つ”’Ｃ仮１−ＩＡ−Ｂｌ＝Ｘ、ＩＢ−Ｃｌ＝Ｙ、Ｉ
ｃ−ＡＩ＝Ｚとすれば、Ｘ≧ｙ　、ｙ＜ｚ　、ｘ＜ｚｏ
量関係生じる。この関係は、欠陥の亀裂方向に依存する
ものの欠陥の特徴として変化をとらえれば、励磁方向に
よる出力変化の有無のみで欠陥と判定できる。具体的に
は、ｘ、ｙ、ｚのいずれか１つに或は、ｘ、ｙ、ｚの論
理和として判定すればよい０又、１５．１６の試験体の
場合でも、第５図の関係より同様にして検出が可能とな
る。According to "'C tentative 1-IA-Bl=X, IB-Cl=Y, I
If c-AI=Z, then X≧y, y<z, x<zo
A quantity relationship arises. Although this relationship depends on the crack direction of the defect, if the change is considered as a characteristic of the defect, it can be determined that it is a defect only by the presence or absence of an output change depending on the excitation direction. Specifically, even in the case of a test specimen of 0 or 15.16, which can be determined by any one of x, y, and z or by the logical sum of x, y, and z, the relationship shown in Figure 5 is satisfied. Detection becomes possible in a more similar manner.

以上の如く本発明方法によれば移動磁界と画像処理装置
とを組み合わせることにより、欠陥のもつ特徴をとらえ
ることができるので、欠陥と有害な擬似欠陥とを識別す
ることができ、これによｆｉＭＴ検査において、欠陥や
有害な擬似欠陥等の影響を除去することができ、試験体
の自動判別化が可能となる等の優れた効果が奏せられる
ものである０As described above, according to the method of the present invention, by combining a moving magnetic field and an image processing device, it is possible to capture the characteristics of defects, so defects and harmful pseudo-defects can be distinguished. In inspection, it is possible to eliminate the influence of defects and harmful pseudo-defects, etc., and it has excellent effects such as automatic discrimination of test specimens.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図（４）、（功、第２図（Ａ）　、　（Ｂ）および
第３図（５）。 ５３）はそれぞれ従来例を説明するための図、第４図は
本発明方法を実施するために用いられる装置の一実施例
を示す図、第５図は第４図に示す一実施例の励磁方向と
欠陥の関係を示す図、第６図は第４図における欠陥抽出
法を説明するための図である。 １・・・試験体、９・・・ＩＴＶカメラ、１１・・・カ
メラコントロールユニット、１Ｂ・・・画像処理装置、
ｘ９，１９’　、１９“・・・画像メモリ、２０・・・
演算部、２ノ・・・磁極移動制御器。 出願人復代理人　弁理士　鈴　江　武　彦１へ２図 第３図 第　１図 （Ｂ） 分 ＩＴＶ７＞メラ吠イ亀イ占５ 第５図 第６図 ０＠４５” ＩＡ−８１冨　Ｘ １ｓ−ｃｌ＝ｖ Ｉｃ−ＡＩ　＝　Ｚ ０　石痣謬オグｊｉ、’、ｙｌ　り； Δ　排衿９久７（甲 ×　菰紛残′留すし ９０″Figure 1 (4), Figure 2 (A), (B) and Figure 3 (5). Fig. 5 is a diagram showing the relationship between the excitation direction and defects in the embodiment shown in Fig. 4, and Fig. 6 explains the defect extraction method in Fig. 4. This is a diagram for DESCRIPTION OF SYMBOLS 1... Test object, 9... ITV camera, 11... Camera control unit, 1B... Image processing device,
x9, 19', 19"...image memory, 20...
Arithmetic unit, No. 2...Magnetic pole movement controller. Applicant Sub-Agent Patent Attorney Takehiko Suzue 1 to 2 Figure 3 Figure 1 (B) Min ITV7 > Meraboi Kamei Sen 5 Figure 5 Figure 6 0 @ 45” IA-81 Tomi X 1s -cl=v Ic-AI=Z 0 stone bruise ogji,', yl ri;

Claims (1)

【特許請求の範囲】[Claims] 磁粉探傷検査において、移動磁界を用いて試験体の欠陥
の磁粉模様を変化させ、これをＩＴＶカメラによって撮
像し、その出力を画像処理装置により画像処理して前記
磁粉模様の変化を検出して前記試験体の欠陥を抽出する
ことを特徴とする磁粉探傷検査における欠陥抽出法。In magnetic particle flaw detection, a moving magnetic field is used to change the magnetic particle pattern of a defect on a test piece, this is imaged by an ITV camera, and the output is image-processed by an image processing device to detect changes in the magnetic particle pattern. A defect extraction method in magnetic particle inspection, which is characterized by extracting defects in a specimen.