JPS6336123B2 - - Google Patents
Info
- Publication number
- JPS6336123B2 JPS6336123B2 JP53123548A JP12354878A JPS6336123B2 JP S6336123 B2 JPS6336123 B2 JP S6336123B2 JP 53123548 A JP53123548 A JP 53123548A JP 12354878 A JP12354878 A JP 12354878A JP S6336123 B2 JPS6336123 B2 JP S6336123B2
- Authority
- JP
- Japan
- Prior art keywords
- coil
- magnetic field
- residual magnetism
- steel material
- magnetic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Description
磁性材料に存在する磁気は外部から受ける磁界
によつて、その材料内部に磁気が保持されるもの
で、これを残留磁気と称する。
磁性材料に与える外部磁界の一つに渦流探傷法
がある。渦流探傷法は、電磁誘導による渦電流の
変化によつて欠陥の検出を行うものであるが、例
えば、鋼材等の強磁性体を探傷する場合、鋼材は
冷間加工などによつて鋼材表面の透磁率が場所に
よつて著しく変化している。したがつて、このま
ま探傷すれば、不均一部によつて雑音の発生する
原因となり、探傷精度が著しく妨げられる。この
ような場合、直流飽和コイルを用い鋼材を直流磁
気飽和させ透磁率の不均一部を少なくしている。
このため、渦流探傷後の鋼材は、直流磁気飽和し
ているため強力な残留磁気が存在することにな
る。鋼材内部に残留磁気があると次のような不都
合を生ずる。
１ その材料を使用した部品は計器の動作および
精度などに影響を与える。
２ その材料の機械加工工程において切屑を吸引
し加工上の妨害となる。
３ 洗浄工程においては鉄粉を吸引し洗浄の妨害
となる。
４ その材料を使用した部品は軸受部分に鉄粉を
吸引して摩擦を生じ不当な摩擦を生じさせる。
５ 磁気探傷検査を受ける場合にその妨害とな
る。
主として上記のような不都合があるため磁性材
料の残留磁気は完全に消滅させる必要がある。
従来より磁性材料を脱磁するために、その材質
や寸法等によつてもつとも効果的な脱磁装置とし
て、例えば特公昭40−15788号、特公昭50−19357
号、特公昭53−16520号などが挙げられる。上記
の特公昭40−15788号に示される脱磁は、交流と
直流を用いて脱磁するため、鋼材の残留磁気の大
きさ及び鋼材の太さによつて、交流磁場の強さを
大きくする必要があり、このため数10KWの電力
を消費するコイルの必要も生じ、又コイルも水冷
となるため、水の消費も生じることになる等の欠
点がある。
本発明の主たる目的は、渦流探傷並びに磁気探
傷後の棒鋼材に残留する強い残留磁気を低電力で
効果的に脱磁を行うことができるようにした脱磁
装置を提供するにある。
本発明の他の目的は、消費電力の増加を無く
し、冷却も必要なく、低電力、省力省資源化で鋼
材の残留磁気を消滅させることができるようにし
た脱磁装置を提供するにある。
以下図面を参照して本発明の実施例を説明す
る。
第１図に示した本発明の脱磁装置は、三段階に
コイルが配置してある。コイルＡは、直流定電流
電源DC，STRによつて励磁されて発生する直流
磁場は、可変可能となつている。上記コイルＡの
次段に配置されたコイルＢは、交流商用周波数に
よつて励磁され、その電流値はあらかじめ決めら
れて、可変はしないようになつている。更に、上
記コイルＢの次段に配置されたコイルＣは、直流
又は交流によつて励磁されるが、いずれもコイル
Ｂによる誘起電力によつて自己励磁している直流
の場合は、回路にダイオード４を入れるが、場合
によつては、コイルＣは除くことも可能である。
上記の回路には、ダイオード４に並列にスイツチ
５が組み込んである。またこれらダイオード４及
びスイツチ５に対して直列に可変抵抗６が組み込
んである。
第２図は、本発明の装置の原理を説明するもの
であるが、磁性材料の特性は、BH曲線によつて
表わされている。
今、渦流探傷器によつて飽和磁化Hmが加えら
れると、鋼材はBm迄磁化される。この磁化され
た後に残る残留磁気は、Br′の点になり、残留磁
気の大きさを示す。残留磁気を保持しようとする
力はHcで表わされ、この値が大きい程、保持す
る力が強いことを示す。今、コイルＡによつて鋼
材には磁場iHDCが加えられ、マイナーループを経
てBr″に移る。このiHDCが強すぎると、逆転する
ので磁場を調整する必要がある。次に、コイルＢ
によつて磁場iHACを加え、Br″に減少した残留磁
気を最少になる迄減少させる。
因みに、第４図に示した従来方式の場合は、
Br′より交流磁場で減少させるため、iH″の加き
交流磁場が必要であり、このため、電力が増加す
ることになる。
次に本発明の作用を説明すると、第１図におい
て、鋼材３は渦流探傷器或いは磁気探傷器によつ
て直流飽和磁化され、磁束１となつて鋼材３の内
部に残留される。鋼材３は、矢印の方向に移動
し、コイルＡを通過する。コイルＡの磁場は、符
号２で示した磁束方向であり、上記の残留磁気１
を打消す作用を行うことになる。ただし、コイル
Ａの磁場の強さは、残留磁気１が反転しない直前
になるよう調整される。
次に、鋼材３はコイルＢに移動され、交流磁場
中を通過し、残つた残留磁気を零附近迄安定に減
少する。次にコイルＣに移動し、尚、地磁気或い
は外部磁界の影響で鋼材内部に残留する磁気を消
滅させるのであるが、その量は材質、寸法によつ
て10〜70ガウス程度であるためコイルＢよりの漏
洩磁場によつてコイルＣに発生する自己誘導起電
力を利用し直流の場合は、スイツチ５をOFFに
しダイオード４によつて整流し直流磁場を発生す
る。交流の場合は、スイツチ５はONとし交流磁
場を得る。いずれも10〜70ガウスの磁場があれば
よく、地磁気或いは外部磁界の影響を受けてない
場合はコイルＣは必要としない。スイツチ５を
ON・OFFにして交流磁場にするか直流磁場にす
るかは実際に行なつて比較し、より効果的である
方法をとればよい。このように、鋼材３はコイル
Ａ、コイルＢ、コイルＣを通過させ、本脱磁装置
より遠ざけることによつて残留磁気を消滅させる
ものである。
なお、コイルＡ、コイルＣの磁場調整は、一本
各に行う必要はなく或るロツドごとに調整するこ
とで足りる。
前記におけるコイルＡの電流調整は、第３図に
示されるとおりである。鋼材の太さが太くなる
程、コイルＡに流す電流範囲は狭い、これは鋼材
が太いものほどコイルＡの効果があらわれている
ことになる。又、鋼材が細くなる程、コイルＡに
流す電流範囲は広くてもよくなる。
本発明の装置により、それぞれ鋼材の太さによ
つて行つた脱磁効果の実験結果は第１表ないし第
５表の通りであつた。
表中の記号の説明
ON…スイツチ５をONにした状態
CFF…スイツチ５をOFFにした状態
min…可変抵抗６の抵抗を最小にした状態
max…可変抵抗６の抵抗を最大にした状態
The magnetism present in a magnetic material is retained within the material by a magnetic field received from the outside, and this is called residual magnetism. Eddy current testing is one of the external magnetic fields applied to magnetic materials. Eddy current testing detects defects using changes in eddy currents caused by electromagnetic induction. For example, when testing ferromagnetic materials such as steel, the surface of the steel material is Magnetic permeability varies significantly depending on location. Therefore, if flaw detection is performed as is, the non-uniform portions will cause noise, which will significantly impede flaw detection accuracy. In such cases, a DC saturation coil is used to apply DC magnetic saturation to the steel material to reduce non-uniform areas of magnetic permeability.
For this reason, the steel material after eddy current flaw detection is saturated with DC magnetism, and therefore strong residual magnetism exists. If there is residual magnetism inside the steel material, the following problems will occur. 1. Parts using the material affect the operation and accuracy of the instrument. 2. In the machining process of the material, chips are sucked in and become a hindrance to the machining process. 3. During the cleaning process, iron powder is sucked in and interferes with cleaning. 4. Parts using this material attract iron powder to the bearing area, causing friction and causing undue friction. 5. It will interfere with the magnetic flaw detection inspection. Mainly because of the above-mentioned disadvantages, it is necessary to completely eliminate the residual magnetism of the magnetic material. To demagnetize magnetic materials, for example, Japanese Patent Publication No. 40-15788, Japanese Patent Publication No. 50-19357 have been used as effective demagnetizing devices depending on the material, size, etc.
No. 53-16520. The demagnetization method shown in the above-mentioned Japanese Patent Publication No. 15788 uses alternating current and direct current, so the strength of the alternating current magnetic field is increased depending on the residual magnetism of the steel material and the thickness of the steel material. Therefore, there is a need for a coil that consumes several tens of kilowatts of power, and since the coil is also water-cooled, there are drawbacks such as water consumption. The main object of the present invention is to provide a demagnetizing device that can effectively demagnetize strong residual magnetism remaining in a steel bar after eddy current flaw detection and magnetic flaw detection with low power. Another object of the present invention is to provide a demagnetizing device that eliminates the increase in power consumption, does not require cooling, and can eliminate residual magnetism in steel with low power consumption, labor and resource savings. Embodiments of the present invention will be described below with reference to the drawings. The demagnetizing device of the present invention shown in FIG. 1 has coils arranged in three stages. The coil A is excited by constant current power supplies DC and STR, and the generated DC magnetic field is variable. Coil B, which is placed next to coil A, is excited by AC commercial frequency, and its current value is determined in advance and is not variable. Furthermore, the coil C placed next to the coil B is excited by direct current or alternating current, but in the case of direct current, which is self-excited by the electromotive force generated by coil B, a diode is installed in the circuit. 4, but depending on the case, coil C may be omitted.
A switch 5 is incorporated in the above circuit in parallel with the diode 4. Further, a variable resistor 6 is installed in series with the diode 4 and switch 5. FIG. 2 explains the principle of the device of the present invention, and the characteristics of the magnetic material are represented by a BH curve. Now, when saturation magnetization Hm is applied by an eddy current flaw detector, the steel material is magnetized to Bm. The residual magnetism that remains after magnetization becomes a point Br', which indicates the magnitude of the residual magnetism. The force that tries to hold residual magnetism is expressed as Hc, and the larger this value, the stronger the holding force. Now, a magnetic field iH DC is applied to the steel by coil A, which moves through a minor loop to Br''. If this iH DC is too strong, it will reverse, so it is necessary to adjust the magnetic field. Next, coil B
By applying a magnetic field iH AC , the residual magnetism reduced to Br'' is reduced to the minimum. Incidentally, in the case of the conventional method shown in Fig. 4,
In order to reduce Br′ with an alternating magnetic field, an additional alternating magnetic field with iH″ is required, which results in an increase in power. Next, to explain the operation of the present invention, in FIG. is DC saturated magnetized by an eddy current flaw detector or a magnetic flaw detector, and becomes a magnetic flux 1 that remains inside the steel material 3.The steel material 3 moves in the direction of the arrow and passes through the coil A. The magnetic field is in the direction of magnetic flux indicated by code 2, and the remanence 1 described above is
This will have the effect of canceling out the However, the strength of the magnetic field of the coil A is adjusted so that the residual magnetism 1 is just before reversal. Next, the steel material 3 is moved to the coil B and passes through an alternating current magnetic field to stably reduce the remaining residual magnetism to near zero. Next, it moves to coil C, which eliminates the residual magnetism inside the steel material due to the influence of earth's magnetism or external magnetic field, but since the amount is about 10 to 70 gauss depending on the material and dimensions, it is In the case of direct current, the switch 5 is turned OFF and rectified by the diode 4 to generate a direct current magnetic field using the self-induced electromotive force generated in the coil C by the leakage magnetic field. In the case of alternating current, switch 5 is turned on to obtain an alternating magnetic field. In either case, a magnetic field of 10 to 70 Gauss is sufficient, and if the magnetic field is not affected by earth's magnetism or an external magnetic field, the coil C is not required. switch 5
You should actually try it out and compare whether to turn it ON/OFF to use an AC magnetic field or a DC magnetic field, and choose the method that is more effective. In this way, the steel material 3 allows the coils A, B, and C to pass through and is kept away from the present demagnetizing device to eliminate residual magnetism. Note that it is not necessary to adjust the magnetic fields of the coils A and C for each rod, and it is sufficient to adjust the magnetic fields for each rod. The current adjustment of the coil A in the above is as shown in FIG. The thicker the steel, the narrower the range of current flowing through the coil A. This means that the thicker the steel, the more effective the coil A becomes. Furthermore, the thinner the steel material is, the wider the range of current flowing through the coil A may be. Tables 1 to 5 show the experimental results of the demagnetizing effect conducted using the apparatus of the present invention, depending on the thickness of the steel material. Explanation of symbols in the table ON...Switch 5 is turned on CFF...Switch 5 is turned off min...The resistance of variable resistor 6 is minimized max...The resistance of variable resistor 6 is maximized
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】
以上説明したように本発明の装置によれば、小
さな電力で極めて効果的な脱磁が実現される。[Table] As explained above, according to the apparatus of the present invention, extremely effective demagnetization can be achieved with small electric power.
第１図は本発明の脱磁装置の構成および結線、
発生磁界などを示す縦断面図、第２図は原理説明
図、第３図はコイルの電流調整の説明図、第４図
は従来方式による構成および結線発生磁界を示
す。
符号の説明、Ａは直流定電流電源により励磁さ
れるコイル、Ｂは交流商用周波数によつて励磁さ
れるコイル、Ｃは直流又は交流によつて励磁され
るコイル、３は被脱磁材である。
FIG. 1 shows the configuration and wiring of the demagnetizing device of the present invention,
FIG. 2 is a diagram for explaining the principle, FIG. 3 is a diagram for explaining coil current adjustment, and FIG. 4 is a diagram showing a conventional configuration and the magnetic field generated by wire connection. Explanation of the symbols: A is a coil excited by a DC constant current power supply, B is a coil excited by an AC commercial frequency, C is a coil excited by DC or AC, and 3 is the material to be demagnetized. .
Claims (1)
直流磁場は可変可能で、かつ脱磁すべき鋼材の残
留磁気のＮ、Ｓ極が反転直前になるように磁界を
加えて残留磁気をマイナーループを経てBH曲線
上のBr′からBr″に移すコイルＡと、該コイルの
次段に配置され、交流商用周波数によつて励磁さ
れ。その電流値は決められて可変しないコイルＢ
とよりなり、これらコイルＡ及びＢ内に脱磁すべ
き鋼材を連続通過させるように構成してなる脱磁
装置。1 Excited by a DC constant current power supply, the generated DC magnetic field is variable, and a magnetic field is applied so that the N and S poles of the residual magnetism of the steel material to be demagnetized are just before reversal, and the residual magnetism is put into a minor loop. Coil A, which moves from Br' to Br'' on the BH curve, and Coil B, which is placed next to this coil and is excited by AC commercial frequency.The current value is fixed and does not change.
The demagnetizing device is constructed so that the steel material to be demagnetized continuously passes through these coils A and B.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12354878A JPS5550609A (en) | 1978-10-09 | 1978-10-09 | Demagnetizer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12354878A JPS5550609A (en) | 1978-10-09 | 1978-10-09 | Demagnetizer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5550609A JPS5550609A (en) | 1980-04-12 |
| JPS6336123B2 true JPS6336123B2 (en) | 1988-07-19 |
Family
ID=14863318
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12354878A Granted JPS5550609A (en) | 1978-10-09 | 1978-10-09 | Demagnetizer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5550609A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6126905A (en) * | 1984-07-16 | 1986-02-06 | Fuji Photo Film Co Ltd | Method and device for degaussing magnetic recording medium |
| DE3500011C2 (en) * | 1985-01-02 | 1986-04-17 | Axel R. Dr.-Ing. 5900 Siegen Hidde | Process for the controlled demagnetization of rod-shaped, ferromagnetic and tempered semi-finished or finished products in the ongoing production process |
| CN120977718B (en) * | 2025-10-22 | 2026-01-30 | 杭州极弱磁场国家重大科技基础设施研究院 | Self-adaptive active-adjustment type demagnetizing circuit and device of magnetic shielding device |
-
1978
- 1978-10-09 JP JP12354878A patent/JPS5550609A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5550609A (en) | 1980-04-12 |
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