JPS60147647A - Method and device for flaw detection - Google Patents

Abstract

PURPOSE:To detect flaws accurately independently of kinds of them by arranging two coils, whose axes are on the same line along the surface of a material to be examined, in parallel and forming periodically a magnetic field in the direction along the surface of the material to be examined and a magnetic field in a different direction on the surface of the material to be examined. CONSTITUTION:Exciting currents having frequencies different from each other are flowed to two coils 31a and 31b, whose axes are placed on the same line along the surface of a material 11 to be examined so that maximum values (or minimum values) of waveforms coincide with each other and the maximum value (or minimum value) of one waveform coincides with the minimum value (or maximum value) of the other. The magnetic field along the surface of the material 11 to be examined and a magnetic field orthogonal to this magnetic field are formed periodically on the surface of the material 11 to be examined which faces both coils 31a and 31b, and change of magnetic flux is detected synchronously by a magnetic field detector 32. Thus, flaw detection is performed intermittently, and flaws are accurately detected independently of their kinds.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は鋼管、スラブ等の被検査材の表面に存する割れ
疵、穴状のピット疵等の表面疵をその性状に関わりなく
正確に検出できる探傷方法及びその実施に使用する装置
を提案するものである。[Detailed Description of the Invention] [Field of Industrial Application] The present invention is capable of accurately detecting surface flaws such as cracks and pit flaws existing on the surface of inspected materials such as steel pipes and slabs, regardless of their properties. This paper proposes a possible flaw detection method and the equipment used for its implementation.

〔従来技術〕[Prior art]

金属材の表面疵の探傷方法としては種々の被破壊検査法
が実用化されており、存在が予想される欠陥に応じて一
種若しくは複数種類の方法が適用されている。Various destructive inspection methods have been put into practical use as methods for detecting surface flaws in metal materials, and one or more methods are applied depending on the defects expected to exist.

例えば予想される疵の方向がある程度定まっている割れ
疵の検出には主として被検査材の表面からの漏洩磁束を
検出する磁気探傷法が適用され、厚み方向に延びるだけ
のビット疵の検出には渦流探傷法が適用されている。For example, magnetic flaw detection, which detects leakage magnetic flux from the surface of the inspected material, is mainly applied to detect cracks whose predicted direction is fixed to some extent, and to detect bit flaws that only extend in the thickness direction. Eddy current flaw detection method is applied.

前者の磁気探傷法は■鉄鋼材料等の＋１！磁性体の表面
欠陥の検出に優れている。■割れが開ｌＺ１シていない
地きずのような欠陥でも検出できる。■欠陥の位置１表
面上の長さの検出が可能であるという長所を有している
。The former magnetic flaw detection method is +1 for steel materials, etc.! Excellent in detecting surface defects in magnetic materials. ■It is possible to detect defects such as ground scratches where the cracks have not opened. (1) Defect position 1 It has the advantage of being able to detect the length on the surface.

また、後者の渦流探傷法は■探傷結果が直接的に電気的
出力として得られる。■非接触であるので試験速度が速
い。０表面欠陥の検出に適している。■欠陥、材質２寸
法変化等に対しても追従でき通用範囲が広い。■信号と
欠陥体積とが略比例関係になる、等の長所を有している
。In addition, in the latter eddy current flaw detection method, (1) the flaw detection results are directly obtained as electrical output. ■Testing speed is fast because it is non-contact. Suitable for detecting zero surface defects. ■It can track defects, material 2-dimensional changes, etc., and has a wide range of applications. (2) It has advantages such as a substantially proportional relationship between the signal and the defect volume.

また、上記磁気探傷法では、疵と直角な方向に磁化した
場合には有効であるが、疵と同方向に磁化した場合には
、疵部分には磁極が生じないので被検査材表面からの漏
洩磁束が微少であり、探傷が不可能であった。しかし現
在では下記に示す様に、複数の磁場を利用する方法で疵
の方向に関係なく探傷できるようになってきた。In addition, the magnetic flaw detection method described above is effective when magnetized in the direction perpendicular to the flaw, but if it is magnetized in the same direction as the flaw, no magnetic pole is generated at the flaw, so there is no magnetic pole from the surface of the material to be inspected. The leakage magnetic flux was so small that flaw detection was impossible. However, as shown below, it has now become possible to detect flaws regardless of their direction by using a method that uses multiple magnetic fields.

例えば第１図に示す様に丸棒鋼１に直接軸方向の通電を
行って円周方向に磁化し、また、丸棒鋼１を囲繞するコ
イルに通電して軸方向に磁化し、前者にて周方向の表面
疵１ａを、後者にて軸方向の表面疵１ｂを各検出する方
法が知られている。For example, as shown in Fig. 1, a round steel bar 1 is directly energized in the axial direction to magnetize it in the circumferential direction, and a coil surrounding the round bar 1 is energized to be magnetized in the axial direction, and the former magnetizes the circumferential direction. A method is known in which surface flaws 1a in the axial direction are detected, and surface flaws 1b in the axial direction are detected using the latter method.

また、第２図に示す様に管材１′を囲繞する１対のコイ
ル２，２と、管材１′の直径方向両側に磁極を対向させ
た磁石３とをタンデムに配し、前者にて管材１′の軸方
向に磁化し、その磁場にて円周方向の表面疵１’ｂを磁
場検出器２ａにて検出し、後者にて管材１′の周方向に
磁化し、その磁場にて軸方向の表面疵１’ａを磁場検出
器３ａにて検出する方法も知られている。In addition, as shown in FIG. 2, a pair of coils 2, 2 surrounding the tube 1' and magnets 3 with opposing magnetic poles on both sides of the tube 1' in the diametrical direction are arranged in tandem, and the former The magnetic field detector 2a detects surface flaws 1'b in the circumferential direction using the magnetic field. A method of detecting surface flaws 1'a in the direction using a magnetic field detector 3a is also known.

しかしながら、金属材の表面に発生する疵は割れ疵以外
にビット疵と呼ばれるものもあり、上記した磁気探傷で
はピント疵を検出し難い。従ってピント疵の検出が必要
な場合は渦流探傷法に依る必要がある。このために被検
査材、その疵性状によっては複数の探傷法に依らざるを
得ないという煩わしさがあった。However, in addition to cracking defects, there are also defects called bit defects that occur on the surface of metal materials, and it is difficult to detect focus defects using the magnetic flaw detection described above. Therefore, if it is necessary to detect focus flaws, it is necessary to rely on the eddy current flaw detection method. Therefore, depending on the material to be inspected and the nature of the flaw, it is necessary to use a plurality of flaw detection methods, which is troublesome.

そして、複数の探傷法を適用する場合には、被検査材の
パスラインに割れ疵、ピント疵夫々専用の探傷装置を設
置する必要があり、このため設備が大型化しそのコスト
が高くなり、また、各探傷装置にて独立的に検査を行う
ものであるので検査コストが高くなるという難点があっ
た。また、上記の如〈従来の磁気探傷法においては被検
査材の磁化手段が大型のものとなり、その検出部の被検
査材への追随性が悪く精度の良い検出が行えないという
難点もあった。When multiple flaw detection methods are applied, it is necessary to install dedicated flaw detection equipment for cracks and focus flaws in the pass line of the inspected material, which increases the size of the equipment and increases the cost. However, since each flaw detection device performs the inspection independently, there is a problem in that the inspection cost is high. In addition, as mentioned above, in the conventional magnetic flaw detection method, the means for magnetizing the material to be inspected is large, and the detection part has a poor ability to follow the material to be inspected, making it difficult to perform accurate detection. .

〔目　的〕〔the purpose〕

本発明は斯かる事情に鑑みてなされたものであり、被検
査材の表面に沿う方向の同一線上に軸心を位置せしめた
２つのコイルに、それらの波形の極大値（又は極小値）
同士が一致するように、また、一方の極大値（又は極小
値）と他方の極小値（又は極大値）とが一致するように
相異なる周波数の励磁電流を通電することにより、両コ
イルと対向する被検査材の表面部分に、これに沿う向き
となる磁場及びこれに直交する向きとなる磁場を周期的
に形成せしめ、これらの磁場の磁束変化を両コイル間に
設けた磁場検出器にて同期的に検出することとして、磁
気探傷、渦流探傷を間欠的に行わしめる如くになし、割
れ疵、ピット疵等の疵の種類に関係なく正確な検出が行
える探傷方法及びその実施に使用する装置を提供するこ
とを目的とする。The present invention has been made in view of the above circumstances, and uses two coils whose axes are located on the same line along the surface of the material to be inspected to determine the maximum value (or minimum value) of their waveforms.
By applying excitation currents of different frequencies so that the two coils match each other, and the local maximum value (or minimum value) of one side matches the local minimum value (or maximum value) of the other side, A magnetic field oriented along and perpendicular to this is periodically formed on the surface of the material to be inspected, and changes in the magnetic flux of these magnetic fields are detected by a magnetic field detector installed between both coils. A flaw detection method in which magnetic flaw detection and eddy current flaw detection are performed intermittently as synchronous detection, and which enables accurate detection regardless of the type of flaw such as cracks and pit flaws, and the equipment used to implement the flaw detection method. The purpose is to provide

〔発明の構成〕[Structure of the invention]

本発明に係る探傷方法は、夫々の軸心が被検査材の表面
に沿う同一線上にあるように並設した２つのコイルの一
方に適宜の周波数の、他のコイルに前記周波数の整数倍
の励磁電流を、一方の励磁電流の波形の極大値（又は極
小値）が他方の励磁電流の波形の極大値及び極小値と実
質的に一致する期間が在るように位相調節して通電し、
前記被検査材の表面の両コイルと対向する部分に、これ
に沿う向きとなる磁場及びこれに直交する向きとなる磁
場を夫々周期的に形成せしめ、この部分に設けた磁場検
出器にて各磁場形成時の磁束変化を検出することを特徴
とする。In the flaw detection method according to the present invention, two coils are arranged in parallel so that their axes are on the same line along the surface of the material to be inspected, one of the coils is set at an appropriate frequency, and the other coil is set at an integral multiple of the frequency. The excitation current is energized with the phase adjusted so that there is a period in which the maximum value (or minimum value) of the waveform of one excitation current substantially matches the maximum value and minimum value of the waveform of the other excitation current,
A magnetic field oriented along the surface of the material to be inspected facing both coils and a magnetic field oriented perpendicular thereto are periodically formed, respectively, and a magnetic field detector provided at this portion is used to detect each of the coils. It is characterized by detecting changes in magnetic flux when a magnetic field is formed.

〔原　理〕[Hara Osamu]

先ず本発明の原理について説明する。第３図に示す様に
軸長方向に移送される被検査材たる鋼管１１の中心の真
上から左右方向に同一距離離隔した位置には、夫々励磁
コイル３］ａ、３１ｂを配置しである。両励磁コイル３
１ａ、３１ｂの軸心は鋼管１１の接線方向を向き、同一
の軸心を共有している。両励磁コイル３１ａ、３１ｂ配
置位置の中央であって、鋼管１１の最上側面から僅かに
上方に離隔した位置には感磁ダイオードからなる磁場検
出器３２を設けである。First, the principle of the present invention will be explained. As shown in FIG. 3, excitation coils 3]a and 31b are respectively arranged at positions spaced apart from each other by the same distance in the left and right direction from directly above the center of the steel pipe 11, which is the material to be inspected, being transferred in the axial direction. . Both excitation coils 3
The axes of 1a and 31b face the tangential direction of the steel pipe 11, and share the same axis. A magnetic field detector 32 made of a magnetism-sensitive diode is provided at the center of the excitation coils 31a, 31b at a position slightly upwardly separated from the uppermost side surface of the steel pipe 11.

図ｔａ＋に示す如き周波数ｆなる励磁電流を第１発振器
４１ａから通電する。また、コイル３１ｂには一例とし
て第２発振器４１ｂから第４図（ｂｌに示す如き倍周波
数２ｆの励磁電流を、その電流波形の極大値（又は極小
値）の位相が周波数ｆの励磁電流の波形の極大値（又は
極小値）の位相と一致し、また、その極大値（又は極小
値）の位相が周波数ｆの励磁電流の極小値（又は極大値
）の位相と一致する期間が在るように通電する。即ち第
４図に示す様に励磁コイル３１ｂに通電される周波数２
ｆの励磁電流の位相が励磁コイル３１ａに通電される周
波数ｆの励磁電流の位相よりも４５°だけ遅れる（又は
１３５°だけ遅れる）ように通電するのである。コイル
３１ａ、　３１ｂの巻回方向が同一であるとすると、両
電流の極大値（又は極小値）が一致する期間では鋼管１
１の表面における両電流による磁場の方向は同一になる
。この場合に両励磁コイル３１ａ、３１ｂの下方に位置
する鋼管１１の表層部には第５図ｒａｔに示す如（鋼管
１１の表面に沿う磁場（以下同方向磁場という）が形成
される。一方、周波数［の電流゛の極小値（又は極大値
）と周波数２ｆの電流の極大値（又は極小値）とが一致
する期間では鋼管１．１の表面における両電流による磁
場の方向は逆になる。An excitation current having a frequency f as shown in FIG. ta+ is applied from the first oscillator 41a. In addition, the coil 31b receives, for example, an excitation current from a second oscillator 41b with a double frequency of 2f as shown in FIG. There is a period in which the phase of the maximum value (or minimum value) matches the phase of the maximum value (or minimum value) of the excitation current, and the phase of the maximum value (or minimum value) matches the phase of the minimum value (or maximum value) of the exciting current of frequency f In other words, as shown in FIG. 4, frequency 2 is applied to the excitation coil 31b.
The current is applied so that the phase of the excitation current f is delayed by 45 degrees (or delayed by 135 degrees) from the phase of the excitation current of frequency f applied to the excitation coil 31a. Assuming that the winding directions of the coils 31a and 31b are the same, the steel pipe 1
The direction of the magnetic field due to both currents on the surface of 1 becomes the same. In this case, a magnetic field along the surface of the steel pipe 11 (hereinafter referred to as a co-directional magnetic field) is formed in the surface layer of the steel pipe 11 located below both excitation coils 31a and 31b, as shown in FIG. During the period in which the minimum value (or maximum value) of the current at frequency 2f and the maximum value (or minimum value) of the current at frequency 2f coincide, the directions of the magnetic fields due to both currents on the surface of the steel pipe 1.1 are reversed.

従って、この場合に側励磁コイル３１ａ、３１ｂ間Ｇ二
番よ第５図（ｂｌに示す如く鋼管１１の表面に対して垂
直となる磁場（以下異方向磁場という）が形成され、こ
の異方向磁場より両励磁コイル３１ａ、３１ｂの下方に
位置する鋼管１１の表面には該磁場を中心とする渦電流
が発生せしめられることになる。このような同方向磁場
及び異方向磁場は第４図るこ示す如（周波数ｆの励磁電
流の波形に応して周期的に現れる。Therefore, in this case, a magnetic field perpendicular to the surface of the steel pipe 11 (hereinafter referred to as a different direction magnetic field) is formed between the side excitation coils 31a and 31b as shown in FIG. Therefore, an eddy current centered on the magnetic field is generated on the surface of the steel pipe 11 located below both excitation coils 31a and 31b.Such a magnetic field in the same direction and a magnetic field in different directions are shown in FIG. (Appears periodically according to the waveform of the excitation current with frequency f.

而して、同方向磁場形成時に鋼管１１の表面Ｇこ割れ疵
Ｃ〔第５図（ａｌ参照）が存在する場合は当該割れ底部
にて同方向磁場から磁束が第５図（Ｊｌ）に示す如く漏
洩する。この漏洩磁束は鋼管１１の表面に垂直な方向の
磁界を検出する磁場検出器３２にて検出されることにな
る。Therefore, when a co-directional magnetic field is formed, if a crack C [see Fig. 5 (al)] exists on the surface of the steel pipe 11, the magnetic flux from the co-directional magnetic field is generated at the bottom of the crack as shown in Fig. 5 (Jl). It leaks like that. This leakage magnetic flux is detected by a magnetic field detector 32 that detects a magnetic field in a direction perpendicular to the surface of the steel pipe 11.

一方、異方向磁場形成時に鋼管１１の表面にピット疵Ｐ
〔第５図（ｂｌ参照〕が存在する場合は当該ピット底部
にて渦電流の向きが乱れ、それに伴ない渦電流による磁
場が乱れ、これが磁場検出器３２にて検出される。そし
て、これら磁場検出器３２の同方向磁場形成時及び異方
向磁場形成時の出力は該磁場検出器３２に接続された同
期検波回路４３ａ及び４３ｂにて夫々同期検波される。On the other hand, pit flaws P appear on the surface of the steel pipe 11 when a magnetic field is formed in a different direction.
[Fig. 5 (see BL]) exists, the direction of the eddy current is disturbed at the bottom of the pit, and the magnetic field due to the eddy current is accordingly disturbed, which is detected by the magnetic field detector 32. Then, these magnetic fields The outputs of the detector 32 when forming a magnetic field in the same direction and when forming a magnetic field in a different direction are synchronously detected by synchronous detection circuits 43a and 43b connected to the magnetic field detector 32, respectively.

これにより割れ疵Ｃ及びビット疵Ｐの検出及び弁別が可
能となるのである。なお、側励磁電流の極大値（又は極
小値）同士又は一方の極大値（又は極小値）と他方の極
小値（又は極大値）の位相を完全に一致せしめる必要は
なく、同方向磁場及び異方向磁場を形成することができ
るだけの範囲内にあればよい。This makes it possible to detect and differentiate cracks C and bit defects P. Note that it is not necessary to completely match the phases of the maximum values (or minimum values) of the side excitation currents or the phases of one maximum value (or minimum value) and the other minimum value (or maximum value); It suffices if it is within a range that can form a directional magnetic field.

〔実施例〕〔Example〕

以下本発明をその実施例を示す図面に基づいて詳述する
。第６図は本発明に係る探傷方法の実施に使用する装置
の検出部周りの構造を示す模式的正面図、第７図はその
左側面図、第８図は検出部の検出器ホルダ周りを拡大し
て示す正面断面図、第９図はその左側半断面図である。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof. Fig. 6 is a schematic front view showing the structure around the detection part of the device used to implement the flaw detection method according to the present invention, Fig. 7 is a left side view thereof, and Fig. 8 is a schematic front view showing the structure around the detector holder of the detection part. FIG. 9 is an enlarged front sectional view, and FIG. 9 is a left half sectional view thereof.

図中１１は鋼管であって、図示しない搬送装置により軸
心回転されつつ軸長方向に移送される。鋼管１１の移送
域の上方には鋼管１１の移送方向に適長離隔した１対の
アーム１２．１２が図示しない駆動手段により鉛直面内
での回動自在に枢支されている。In the figure, reference numeral 11 denotes a steel pipe, which is rotated about its axis and transported in the axial direction by a transport device (not shown). Above the transfer area of the steel pipe 11, a pair of arms 12.12 are supported by a drive means (not shown), which are spaced apart by an appropriate length in the direction of transfer of the steel pipe 11, so as to be rotatable in a vertical plane.

アーム１２．１２の先端部には本発明装置の検出部Ａが
鉛直面内での回動自在に枢支されている。検出部Ａば鋼
管１１がその下方に移送されて来て、その先端部が通過
した時点でアーム１２．１２の下方への回動により下降
せしめられ鋼管１１の上側面に当接せしめられ本発明の
探傷が行われる。鋼管１１が検出部Ａの下方にない場合
はアーム１２．１２の上方への回動により所定の退避位
置迄上昇せしめられる。At the tip of the arm 12.12, the detection section A of the device of the present invention is pivotally supported in a vertical plane. In the detection part A, the steel pipe 11 is transferred downward, and when the tip thereof passes, it is lowered by the downward rotation of the arm 12.12 and brought into contact with the upper surface of the steel pipe 11. flaw detection is carried out. If the steel pipe 11 is not below the detection part A, it is raised to a predetermined retracted position by upward rotation of the arm 12.12.

なお、アーム１２．１２の鉛直方向への回動は鋼管１１
の移送域に設置された図示しないフ第１〜センサの管端
検知信号により行われる。In addition, the rotation of the arm 12.12 in the vertical direction is caused by the steel pipe 11.
This is performed using a tube end detection signal from a sensor (not shown) installed in the transfer area.

次に検出部Ａについて説明する。アーム１２．１２の先
端部には矩形状の検出部取付板１３が水平連結ビン１４
．１４により左右方向への揺動可能に枢支連結されてい
る。取付板１３の下面の左側には円筒状の追従ローラ支
持部材１５．１５が垂設されており、その先端に側面視
倒立Ｕ字状の追従ローラ支承部材１５ａ、１５ａを備え
ている。取付板１３下方の右側には該取付板１３の下面
に垂設された支持部材１３ａを介して同様の追従ローラ
支持部材１６　（図面では手前側のみ現われている）が
その長手方向を水平方向として取付けられている。その
先端には追従ローラ支承部材１５ａと同様の追従ローラ
支承部材１６ａを左方に向けて備えている。各支承部材
１５ａ、１５ａ。Next, the detection section A will be explained. At the tip of the arm 12.12, a rectangular detection unit mounting plate 13 is attached to a horizontal connecting bin 14.
．． 14, which is pivotally connected so as to be swingable in the left and right direction. A cylindrical follow-up roller support member 15.15 is vertically provided on the left side of the lower surface of the mounting plate 13, and has follow-up roller support members 15a, 15a each having an inverted U-shape in side view at its tip. On the lower right side of the mounting plate 13, a similar follow-up roller support member 16 (only the front side is visible in the drawing) is connected via a support member 13a vertically installed on the lower surface of the mounting plate 13, with its longitudinal direction being the horizontal direction. installed. A follow-up roller support member 16a similar to the follow-up roller support member 15a is provided at its tip facing leftward. Each support member 15a, 15a.

１６ａには追従ローラ１７．１７・・・を鋼管１１の軸
心と平行な軸心回りの回転自在に軸支してあり、追従ロ
ーラ１７，１７・・・の鋼管１１の外周面転接位置は鋼
管１１の中心を通る鉛直面に関して左右対称となってい
る。各追従ローラ１７，１７・・・は軸心回転する鋼管
１１の上側面上に転接し、検出部Ａの鋼管ＩＩに対する
追随を可能ならしめている。Follower rollers 17, 17... are rotatably supported on 16a so as to be rotatable about an axis parallel to the axis of the steel pipe 11, and the positions of the follower rollers 17, 17... in contact with the outer peripheral surface of the steel pipe 11 are fixed. are symmetrical with respect to a vertical plane passing through the center of the steel pipe 11. Each of the following rollers 17, 17, . . . is in rolling contact with the upper surface of the steel pipe 11 rotating on its axis, allowing the detection section A to follow the steel pipe II.

取付板１３の下面中央には側面視Ｕ字状の支持部材１８
が取付けられている。支持部材１８の底面中央には筒状
のベアリングハウジング１９がその長手方向を上下方向
として嵌着されており、該ベアリングハウジング１９に
はスラストヘアリング２０を同心的に嵌合しである。ス
ラストベアリング２０には摺動軸２１を内嵌してあり、
その上端には円板状のストッパ２２を固着してあり、摺
動軸２１のスラストベアリング２０からの抜けを防止し
ている。摺動軸２１の下端部は少し大径の鍔部２１ａと
してあり、この鍔部２１ａとベアリングハウジング１９
との間に摺動軸２１を下方へ付勢すべく摺動軸２１に囲
繞させてコイルバネ２８を介装しである。該鍔部２１ａ
の下端には長方形状のスプリング受板２３が固着されて
おり、該スプリング受板２３の下面には正面視門形のボ
ルダ支承部材２４が固着されている。支承部材２４の両
側壁には夫々ベアリング２５．２’５を軸心方向を左右
方向として嵌合しである。支承部材２４間には、支承部
材２４よりも左右方向長さが少争短かく前後方向長さが
長い、下面が開口した直方体状のボルタカバー２６が遊
嵌されており、その左右側壁中央部に設けた軸部２６ａ
　、　２６ａをベアリング２５．２５の内輪に嵌着しで
ある。これによりホルダカバー２６はヘアリング２５．
２５の軸心回りの回動が自在となっている。スプリング
受板２３〜ボルダ力バー２６間の所定の位置にはスプリ
ング２７　、２７を係着して、ボルダカバー２６を下方
に向けて付勢している。スプリング２７，２７　、コイ
ルハネ２８は鋼管１１に曲り、変形等が存在する場合の
検出部へのヘアリング２５．２５の軸心回り及び上下方
向への振動を吸収するだめのものであり、これにより検
出部への鋼管１１に対する追随性の向上を図っている。At the center of the lower surface of the mounting plate 13 is a support member 18 that is U-shaped in side view.
is installed. A cylindrical bearing housing 19 is fitted into the center of the bottom surface of the support member 18 with its longitudinal direction facing up and down, and a thrust hair ring 20 is fitted concentrically into the bearing housing 19. A sliding shaft 21 is fitted inside the thrust bearing 20.
A disk-shaped stopper 22 is fixed to its upper end to prevent the sliding shaft 21 from coming off the thrust bearing 20. The lower end of the sliding shaft 21 has a slightly larger diameter flange 21a, and this flange 21a and the bearing housing 19
A coil spring 28 is interposed between the sliding shaft 21 and the sliding shaft 21 to urge the sliding shaft 21 downward. The flange 21a
A rectangular spring receiving plate 23 is fixed to the lower end of the spring receiving plate 23, and a boulder support member 24 having a gate shape in front view is fixed to the lower surface of the spring receiving plate 23. Bearings 25.2'5 are fitted into both side walls of the support member 24, respectively, with the axial direction being the left and right directions. A rectangular parallelepiped-shaped bolt cover 26 with an open lower surface is loosely fitted between the support members 24 and has a slightly shorter length in the left-right direction and a longer length in the front-rear direction than the support members 24. The shaft portion 26a provided in
, 26a is fitted onto the inner ring of the bearing 25.25. As a result, the holder cover 26 is attached to the hair ring 25.
It can freely rotate around the axis of 25. Springs 27 are engaged at predetermined positions between the spring receiving plate 23 and the boulder force bar 26 to urge the boulder cover 26 downward. The springs 27, 27 and the coil spring 28 are used to absorb vibrations around the axis of the hair ring 25, 25 to the detection unit and in the vertical direction when the steel pipe 11 is bent or deformed. This is intended to improve the ability to follow the steel pipe 11 to the detection section.

ホルダカバー２６の下縁には平面視寸法がホルダカバー
２６と同様の検出器ホルダ２９が着脱自在に取付けられ
ている。検出器ホルダ２９の左右対称の位置には前後方
向に長い側面視額縁状のコイルボヒン３０ａ　、　３０
ａを配設しである。コイルホヒン３０ａ　、　３０ａは
その軸心方向が左右方向となる様にしてあり、その周縁
の溝に励磁コイル３１ａ、３１ｂを巻回しである。励磁
コイル３１ａ、、３１ｂの前後方向長さは次に述べる磁
場検出器、３２．３２・・・の個数又は鋼管１１の送り
速度により定まる探傷域を考慮して適宜の長さに選定さ
れている。A detector holder 29, which has the same dimensions as the holder cover 26 in plan view, is detachably attached to the lower edge of the holder cover 26. At symmetrical positions on the detector holder 29 are coil bohins 30a, 30 which are long in the front and back direction and have a frame shape when viewed from the side.
A is arranged. The coil hoins 30a, 30a are arranged so that their axial center directions are in the left-right direction, and excitation coils 31a, 31b are wound around grooves on their peripheries. The length of the excitation coils 31a, 31b in the longitudinal direction is selected to be an appropriate length in consideration of the flaw detection area determined by the number of magnetic field detectors, 32, 32, etc. described below or the feed rate of the steel pipe 11. .

励磁コイル３１ａ、３１ｂ間中央には８個（図面でば４
個のみ現われている）の磁場検出器３２．３２・・・を
コイル３１ａ、３１ｂの前後方向長さに応して一連装置
してあり、探傷域の拡大を図っている。磁場検出器３２
．３２・・・は検出素子として感磁ダイオ−１：を用い
ており、励磁コイル３１ａ、　３１ｂにより鋼管１１の
表面に周期的に形成される既述した如き同方向磁場及び
異方向磁場の磁束変化を検出し、各磁場検出器３２．３
２・・・に接続されたコネクタ３３．３３・・・を介し
て所定の電気信号を後述する信号処理回路Ｂ（第１０図
参照）に入力する。検出器ホルダ２９の下面には正面視
で上部が開口されたコの字状のガイドシュー３４が取付
けられている。ガイドシュー３４は耐摩耗性に冨む材料
、例えばセラミックスからなるものであって検出器ホル
ダ２９の摩耗を防１トするためのものである。There are 8 coils (4 in the drawing) in the center between the excitation coils 31a and 31b.
A series of magnetic field detectors 32, 32, . Magnetic field detector 32
．． 32... uses a magnetosensitive diode 1 as a detection element, and detects magnetic flux changes of the same direction magnetic field and different direction magnetic field as described above, which are periodically formed on the surface of the steel pipe 11 by the excitation coils 31a and 31b. each magnetic field detector 32.3
A predetermined electrical signal is inputted to a signal processing circuit B (see FIG. 10), which will be described later, through connectors 33, 33, . . . connected to 2, . A U-shaped guide shoe 34 whose top is open when viewed from the front is attached to the lower surface of the detector holder 29 . The guide shoe 34 is made of a highly wear-resistant material, such as ceramics, and is used to prevent the detector holder 29 from being worn.

次に信号処理回路Ｂについて第１Ｏ図に基づき説明する
。第１０図は信号処理回路Ｂのブロック図である。コイ
ル３１ａには第１発振器４１ａから第１１図（ａｌに示
す如き周波数２．５　ｋＨｚの高周波電流が通電され、
また、コイル３１ｂには第２発振器４１１）から前記周
波数の倍周波数の第１１図（ｂｌに示す如き５　ｋＨｚ
の高周波電流が通電される。なお、コイル３１ｂに通電
される高周波電流の周波数はコイル３１ａに通電される
周波数の倍周波数のものに限るものではなく、既述した
如く極大値（又は極小値）同士又は一方の極大値（又は
極小値）と他方の極小値（又は極大値）とが一致する期
間が周期的に現れる条件を満たず、整数倍の周波数のも
のであれはよい。Next, the signal processing circuit B will be explained based on FIG. 1O. FIG. 10 is a block diagram of the signal processing circuit B. A high frequency current with a frequency of 2.5 kHz as shown in FIG. 11 (al) is applied to the coil 31a from the first oscillator 41a.
Further, the coil 31b receives a 5 kHz signal from a second oscillator 411), which is a double frequency of the above frequency, as shown in FIG. 11 (bl).
A high frequency current is applied. Note that the frequency of the high-frequency current applied to the coil 31b is not limited to a frequency that is double the frequency applied to the coil 31a, and as described above, the frequency of the high-frequency current applied to the coil 31b is not limited to the frequency that is twice the frequency applied to the coil 31a, and as described above, the maximum value (or minimum value) may be connected to each other, or the maximum value (or It is acceptable if the frequency is an integer multiple and does not satisfy the condition that a period in which one local minimum value (or local maximum value) coincides with the other minimum value (or maximum value) appears periodically.

４２は移相器であって、第１発振器４１ａ出力を利用し
て第２発振器４１　ｂ出力の位相調節を行うために使用
される。即ち、第１１図（ａ）に示す電流波形の極大値
（又は極小値）の位相と第１０図参照）に示す電流波形
の極大値（又は極小値）の位相とが一致する期間が在る
ように、また、第１１図（ａ）の電流波形の極小値（又
は極大値）の位相と第１１図（ｂｌの電流波形の極大値
（又は極小値）の位相とが一致する期間が在るように位
相調節するものであり、このように倍周波を用い極大値
（又は極小値）同士又は一方の極大値（又は極小値）と
他方の極小値（又は極大値）を一致させるには、第２発
振器４１ｂ出力を第１発振器４１ａ出力に対して４５°
遅らせる。A phase shifter 42 is used to adjust the phase of the output of the second oscillator 41b using the output of the first oscillator 41a. That is, there is a period in which the phase of the maximum value (or minimum value) of the current waveform shown in FIG. 11(a) matches the phase of the maximum value (or minimum value) of the current waveform shown in FIG. 10). As shown, there is also a period in which the phase of the minimum value (or maximum value) of the current waveform in FIG. In this way, the phase is adjusted so that the maximum value (or minimum value) matches each other, or one maximum value (or minimum value) matches the other minimum value (or maximum value) using double frequency waves. , the output of the second oscillator 41b is set at 45° with respect to the output of the first oscillator 41a.
delay.

これにより、第１１図（ａｌ、　（ｂｌの電流波形の極
大値（又は極小値）の位相が一致する期間では鋼管１１
の表面に同方向磁場が形成され、また、第１１図（ａ）
。As a result, during the period when the phases of the maximum values (or minimum values) of the current waveforms in FIG.
A codirectional magnetic field is formed on the surface of the
.

（ｂ）の電流波形の極小値（又は極大値）と極大値（又
は極小値）の位相とが一致する期間では異方向磁場が形
成されることになる。各磁場検出器３２゜３２・・・は
これらの磁場の磁束変化を検出し、この磁束変化に応じ
た電気信号を同期検波回路４３ａ及び４３ｂに夫々出力
する。同期検波回路４３ａには第１発振器４１ａから第
１１図ｆｃｌに示す如く第１０図参照）、　ｆｂ）の電
流波形の極大値が一致する期間に現れる道幅の同期パル
スが入力されるようになっており、該同期パルスが入力
される都度磁場検出器３２　、３２・・・からの入力信
号を同期検波し、同方向磁場の磁束変化を検出する。こ
の検波結果は第１２図（ａｌに示す様な極大値及び極小
値を有する磁気探傷型の信号波形として得られる。この
検波結果はレコーダ４４ａにて記録され、また、比較器
４５ａに入力される。Different direction magnetic fields are formed in the period in which the phases of the minimum value (or maximum value) and the maximum value (or minimum value) of the current waveform shown in (b) match. Each magnetic field detector 32, 32, . The synchronous detection circuit 43a receives from the first oscillator 41a, as shown in FIG. Each time the synchronization pulse is input, input signals from the magnetic field detectors 32, 32, . This detection result is obtained as a magnetic flaw detection type signal waveform having maximum and minimum values as shown in FIG. .

比較器４５ａには第１２図（ａ）に二点鎖線で示す如く
割れ疵Ｃの有害、無害の判断基準となる闇値が設定され
ており、同期検波回路４３ａからの入力信号の極大値が
該闇値よりも大なる場合は有害疵検出信号として図示し
ないマーキング装置に入力させる。The comparator 45a is set with a dark value, which is a criterion for determining whether the crack C is harmful or harmless, as shown by the two-dot chain line in FIG. If it is larger than the darkness value, it is input to a marking device (not shown) as a harmful flaw detection signal.

これにより鋼管Ｉ】にはマーキングが施される。As a result, the steel pipe I] is marked.

一方、同期検波回路４３ｂには第２発振器４１ｂから第
１１図（ｃｌ）に示す如く第１１図ｆａｌの電流波形の
極小値と第１１図ｆｂｌの電流波形の極大値とが一致す
る期間に現れる通電の同期パルスが入力されるようにな
っており、該同期パルスが入力される都度磁場検出器３
２．３２・・・からの入力信号を同期検波し、異方向磁
場の磁束変化を検出する。この検波結果は第１２図（ｂ
ｌに示す様な極小値のみを有する渦流探傷型の信号波形
として得られる。この検波結果はレコーダ４４ｂにて記
録され、また、比較器４５ｂに入力される。比較器４５
ｂには第１２図（ｂ）に二点鎖線で示す如きピッ＋−ｉ
Ｐの有害、無害の判Ｗ１基準となる闇値が設定されてお
り、同期検波４３ｂからの入力信号の極小値が該闇値よ
りも小なる場合は有害疵検小信号をマーキング装置に入
力させる。これにより鋼管１１にはマーキングが施され
る。On the other hand, the second oscillator 41b appears in the synchronous detection circuit 43b during the period when the minimum value of the current waveform of fal in FIG. 11 and the maximum value of the current waveform of fbl in FIG. 11 match, as shown in FIG. A synchronous pulse of energization is input, and each time the synchronous pulse is input, the magnetic field detector 3
2. Perform synchronous detection of input signals from 32... and detect changes in magnetic flux of magnetic fields in different directions. This detection result is shown in Figure 12 (b
It is obtained as an eddy current flaw detection type signal waveform having only the minimum value as shown in l. This detection result is recorded by the recorder 44b and is also input to the comparator 45b. Comparator 45
b has a pitch +-i as shown by the two-dot chain line in Fig. 12(b).
A dark value is set as a reference W1 for determining whether P is harmful or harmless, and if the minimum value of the input signal from the synchronous detection 43b is smaller than the dark value, a harmful defect detection small signal is input to the marking device. . As a result, the steel pipe 11 is marked.

〔効　果〕〔effect〕

次に本発明の効果を実施例に基づき明らかにする。第１
３図は割れ疵Ｃ，ピント疵Ｐに相応する人工欠陥を本発
明により検出した場合の検出結果を示すクラブである。Next, the effects of the present invention will be explained based on examples. 1st
FIG. 3 shows a club showing the detection results when artificial defects corresponding to cracks C and focus defects P are detected by the present invention.

第１３図＋ａ）は割れ疵Ｃに相応する人工欠陥を検出し
た場合の磁場検出器の同方向磁場、異方向磁場における
磁束変化の検出に係る出力レベルを縦軸に、また、割れ
ｉ＋ｔ　ｃの深さを横軸にとって示すグラフである。ク
ラブから明らかな様に割れ疵Ｃにあっては、磁場検出器
の出力レベルは同方向磁場の検出レベルが異方向磁場の
それよりも十分大きく現れるので両者の弁別が明瞭に行
なえる。Figure 13+a) shows the output level of the magnetic field detector for detecting changes in magnetic flux in the same direction magnetic field and the different direction magnetic field when an artificial defect corresponding to crack C is detected, and also shows the output level of the magnetic field detector for detecting magnetic flux changes in the same direction magnetic field and different direction magnetic field when an artificial defect corresponding to crack C is detected. It is a graph showing depth on the horizontal axis. As can be seen from the club, in the case of crack C, the output level of the magnetic field detector for the magnetic field in the same direction appears to be sufficiently higher than that for the magnetic field in the different direction, so that the two can be clearly distinguished.

第１３図ｆｂ）ばピット疵Ｐに相応する人工欠陥を検出
しノこ場合の磁場検出器の同方向磁場、異方向磁場にお
ける磁束変化の検出に係る出力レベルを縦軸に、また、
ビット疵Ｐの深さを横軸にとって示すグラフである。グ
ラフから明らかなようにピッ１−疵Ｐにあっては、異方
向磁場の検出レベルが同方向磁場のそれよりも十分大き
く現れるので両者の弁別が明瞭に行なえる。Fig. 13 fb) In this case, the output level of the magnetic field detector for detecting changes in magnetic flux in the same direction magnetic field and different direction magnetic field is plotted on the vertical axis, when an artificial defect corresponding to a pit flaw P is detected.
It is a graph showing the depth of a bit flaw P on the horizontal axis. As is clear from the graph, in the case of P1-Flaw P, the detection level of the magnetic field in the different direction appears to be sufficiently higher than that of the magnetic field in the same direction, so that the two can be clearly distinguished.

第１４図は本発明により深さの異なる割れ疵、ピット疵
を探傷した結果を示ずチャー１−である。第１４図（ａ
ｌは同方向磁場、（ｂ）は異方向磁場の磁束変化を示す
ものであり、縦軸は夫々の検出レベルを示している。グ
ラフから明らかな様に両者の弁別か可能である。また、
疵深さと検出レベルが比例関係にあるので疵深さが定量
的にまる。FIG. 14 does not show the results of detecting cracks and pit defects of different depths according to the present invention; it is Char 1-. Figure 14 (a
1 shows the magnetic flux change in the same direction magnetic field, and (b) shows the magnetic flux change in the different direction magnetic field, and the vertical axis shows the detection level of each. As is clear from the graph, it is possible to distinguish between the two. Also,
Since the flaw depth and the detection level are in a proportional relationship, the flaw depth can be determined quantitatively.

なお、上述の実施例では本発明を鋼管に適用する場合に
ついて述へたか、スラフ等の鋼材についても適用でき、
更には鋼材以外の他の金属材についても通用できること
は勿論である。In addition, in the above embodiments, the present invention is applied to steel pipes, but it can also be applied to steel materials such as slough.
Furthermore, it goes without saying that it can also be applied to metal materials other than steel.

以上詳述した如く本発明による場合は、被検査材の表面
に同方向磁場及び異方向磁場を周期的に形成−已しめ、
疵が存する場合の同方向磁場及び異方向磁場の磁束の変
化を磁場検出器にて検出するものであるので、疵の性状
に関係なく、即ち割れ疵、ピット疵等の疵の種類に関係
なく正確な検出が行え、従来方法の如く疵の種類に応し
て複数の探傷法を適用する必要がなく、設備シスト１検
査コストの低減が図れる。更には検出部を小型軽量化で
きるので被検査材表面への追随性の向」二が図れ、精度
の良い検出が可能となる等、本発明は優れた効果を奏す
る。As detailed above, according to the present invention, a magnetic field in the same direction and a magnetic field in different directions are periodically formed on the surface of the material to be inspected,
Since the magnetic field detector detects changes in the magnetic flux of the same direction magnetic field and the different direction magnetic field when a flaw exists, it is possible to detect the change regardless of the nature of the flaw, i.e. regardless of the type of flaw such as a crack or a pit flaw. Accurate detection can be performed, there is no need to apply multiple flaw detection methods depending on the type of flaw as in conventional methods, and the cost of inspecting the equipment system 1 can be reduced. Furthermore, since the detection section can be made smaller and lighter, it is possible to improve the ability to follow the surface of the material to be inspected, thereby enabling highly accurate detection, and other excellent effects of the present invention.

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

第１．２図は従来方法の実施状態を示す模式図、第３〜
５図は本発明の原理説明図、第６図は本発明装置の検出
部周りの構造を示す模式的正面図、第７図はその左側面
図、第８図は検出器ホルダ周りを拡大して示す正面断面
図、第９図はその左側半断面図、第１０図は信号処理回
路のブロック図、第１１図はその動作説明のための信号
波形図、第１２図は同期検波回路の検出結果を示すグラ
フ、第１３図は本発明により割れ疵、ビット疵に相応す
る人工欠陥を検出した場合の結果を示すクラブ、第１４
図は本発明により深さの異なる割れ疵、ピット疵を探傷
した結果を示すチャートである。 １１・・・鋼管　３１ａ、３１ｂ・・・励磁コイル　３
２．３２・・・磁場検出Ｂ４１ａ・・・第１発振器　４
１ｂ・・・第２発振器４２・・・移相器　４３ａ、４３
ｂ・・・同期検波回路　Ａ・・・検出部　Ｂ・・・信号
処理回路 特　許　出願人　住友金属工業株式会社代理人　弁理士
　河　野　登　夫 笛　３　図 第什図 ０．５　１．（１１，５ ，Ｗコ　（ｌ＋１η） 第　１２　図 ０．５　＋、８　１．５ 深さく１１１？Ｔｌ＋ ン呆１１５．市 第 １４　聞 手続補正寮（自発） 昭和５９年６月８日 ノ０発明の名称　探傷方法及び装置 ３、補正をする者 事件との関係　特許出願人 ダ１代理人 ｊ、補正の対象 明細書の「発明の詳細な説明」の梱及び図面２、補正の
内容 ６−１　「発明の詳細な説りＩ」の楠 ｉｌｌ　＃Ａ細書の第１４頁１２行目乃至１４行目に［
コイルボビン３０ａ、３０ａｔ配設しである。コイルボ
ビン３０ａ、３０ａは］とあるを、［コイへ３０ａ、３
０ｂｆｆ配設しである。コイルボビン３０ａ。 ３０ｂは」と訂正する。 ６−２図曲 第９図を別紙のとお９訂正する。 ２　添付書類の目録 ＋１１訂正図面　１通Figure 1.2 is a schematic diagram showing the implementation state of the conventional method, and Figures 3-
Figure 5 is a diagram explaining the principle of the present invention, Figure 6 is a schematic front view showing the structure around the detection section of the device of the present invention, Figure 7 is a left side view thereof, and Figure 8 is an enlarged view of the area around the detector holder. 9 is a left half sectional view, FIG. 10 is a block diagram of the signal processing circuit, FIG. 11 is a signal waveform diagram for explaining its operation, and FIG. 12 is a detection diagram of the synchronous detection circuit. A graph showing the results, FIG. 13 is a club showing the results when artificial defects corresponding to cracks and bit defects are detected according to the present invention.
The figure is a chart showing the results of testing cracks and pits of different depths according to the present invention. 11... Steel pipe 31a, 31b... Excitation coil 3
2.32...Magnetic field detection B41a...First oscillator 4
1b...Second oscillator 42...Phase shifter 43a, 43
b...Synchronous detection circuit A...Detection section B...Signal processing circuit patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono 3 Figure 0.5 1. (11,5,Wco (l+1η)) No. 12 Fig. 0.5 +, 8 1.5 Depth 111? Title of the invention Flaw detection method and device 3, Relationship with the case of the person making the amendment Patent applicant D1 Attorney J, Packaging and drawings of the "detailed description of the invention" of the specification subject to the amendment 2, Contents of the amendment 6- 1 In "Detailed Explanation of the Invention I" Kusunoki ill #A, page 14, lines 12 to 14 [
Coil bobbins 30a and 30at are provided. Coil bobbins 30a, 30a are], [coil bobbins 30a, 3
0bff is installed. Coil bobbin 30a. 30b,” he corrected. 6-2 Figure 9 is corrected as shown in the attached sheet. 2 List of attached documents + 1 copy of 11 corrected drawings

Claims (1)

【特許請求の範囲】 １、夫々の軸心が被検査材の表面に沿う同一線上にある
ように並設した２つのコイルの一方に適宜の周波数の、
他方のコイルに前記周波数の整数倍の励磁電流を、一方
の励磁電流の波形の極大値（又は極小値）が他方の励磁
電流の波形の極大値及び極小値と実質的に一致する期間
が在るように位相調節して通電し、前記被検査材の表面
の両コイルと対向する部分に、これに沿う向きとなる磁
場及びこれに直交する向きとなる磁場を夫々周期的に形
成せしめ、この部分に臨ませた磁場検出器にで各磁場形
成時の磁束変化を検出することを特徴とする探傷方法。 ２、夫々の軸心が被検査材の表面に沿う同一線上にある
ように並設した第１．第２コイルと、該第１コイルに適
宜の周波数の第１励磁電流を通電する第１発振器と、 前記第２コイルに前記周波数の整数倍の周波数の第２励
磁電流を、その波形の極大値（又は極小値）の位相が前
記第１励磁電流の波形の極大値及び極小値の位相と実質
的に一致する期間が在るように通電する第２発振器と、 前記第１．第２コイル間に設けて、被検査材の表面に臨
ませる磁場検出器と、 第１．第２励磁電流の波形の極大値又は極小値の位相が
実質的に一致する期間の磁場検出器の出力を同期検出す
る第１検出回路と、第１励磁電流の波形の極大値（又は
極小値）の位相が第２励磁電流の波形の極小値（又は極
大値）の位相と実質的に一致する期間の磁場検出器の出
力を同期検出する第２検出回路とを具備することを特徴
とする探傷装置。[Claims] 1. At an appropriate frequency, one of the two coils is installed in parallel so that the axis of each coil is on the same line along the surface of the material to be inspected.
An excitation current having an integral multiple of the frequency is applied to the other coil, and there is a period in which the maximum value (or minimum value) of the waveform of one excitation current substantially matches the maximum value and minimum value of the waveform of the other excitation current. Electricity is supplied with the phase adjusted so that the surface of the material to be inspected is opposed to both coils, and a magnetic field oriented along the same and a magnetic field oriented perpendicular to the coils are periodically formed, respectively. A flaw detection method characterized by detecting changes in magnetic flux when each magnetic field is formed using a magnetic field detector facing the part. 2. The first. a second coil; a first oscillator that supplies a first excitation current with an appropriate frequency to the first coil; and a second excitation current with a frequency that is an integral multiple of the frequency to the second coil, and a maximum value of the waveform thereof. a second oscillator that is energized so that there is a period in which the phase of the first excitation current (or the minimum value) substantially matches the phase of the maximum value and the minimum value of the waveform of the first excitation current; a magnetic field detector provided between the second coils and facing the surface of the material to be inspected; 1. A first detection circuit that synchronously detects the output of the magnetic field detector during a period in which the phases of the maximum value or minimum value of the waveform of the second excitation current substantially match; ) is characterized by comprising a second detection circuit that synchronously detects the output of the magnetic field detector during a period in which the phase of the second excitation current substantially coincides with the phase of the minimum value (or maximum value) of the waveform of the second excitation current. Flaw detection equipment.