EP0243564A2 - Method and device for demagnetizing steel - Google Patents

Method and device for demagnetizing steel Download PDF

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Publication number
EP0243564A2
EP0243564A2 EP86730189A EP86730189A EP0243564A2 EP 0243564 A2 EP0243564 A2 EP 0243564A2 EP 86730189 A EP86730189 A EP 86730189A EP 86730189 A EP86730189 A EP 86730189A EP 0243564 A2 EP0243564 A2 EP 0243564A2
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EP
European Patent Office
Prior art keywords
electromagnet
load
electromagnets
demagnetization
switches
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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.)
Withdrawn
Application number
EP86730189A
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German (de)
French (fr)
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EP0243564A3 (en
Inventor
Hans Ing.-Grad. Winter
Heinz-Günter Platen
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Vodafone GmbH
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Mannesmann AG
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Publication date
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Publication of EP0243564A2 publication Critical patent/EP0243564A2/en
Publication of EP0243564A3 publication Critical patent/EP0243564A3/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F13/00—Apparatus or processes for magnetising or demagnetising
    • H01F13/006—Methods and devices for demagnetising of magnetic bodies, e.g. workpieces, sheet material

Definitions

  • the invention relates to a method for demagnetizing steels, which were held by an electromagnet, and an arrangement for performing the method.
  • a demagnetization device In a demagnetization device according to DE-OS 32 38 609, the object to be demagnetized is guided in the axial direction through an inner coil passage.
  • This demagnetization process requires an additional transport device either for the coil or for the object to be demagnetized, as well as an additional work step. This process works with AC voltage.
  • the object of the invention is therefore to provide a simple method for demagnetizing steels which were held by an electromagnet excited with direct current. This object is achieved by the method steps according to the main claim.
  • the position of the electromagnet can be precisely predetermined and is not purely accidental, as is possible when the electromagnet attracts the steel. This is particularly important when clamping tools in processing machines.
  • the electromagnet is only released after the demagnetization has been completed, depending on The mass and shape of the held or lifted object is 10 to 20 seconds. This expenditure of time is very small in relation to the demagnetization process according to DE-OS 32 38 609.
  • the demagnetization takes place by decaying alternating current, the amplitude and cycle times of which can be set.
  • the setting of the amplitudes and cycle times depends on the alloy of the material as well as on the mass and shape of the workpiece. In the process, it is also immaterial whether e.g. a thin-walled tube or a solid workpiece has been lifted or clamped.
  • the first counter circuit is just as high (100% of the original) in the excitation; only then does the controlled decay of the excitation take place.
  • the counter-switching takes place in smaller stages, which are then increased (e.g. 100%, 95%, 90%, 80%, 60%, 40%, 20%); then the excitement decays, leaving residual field strengths of less than 10 Oe (Oersted).
  • a controlled, antiparallel thyristor bridge which can be released by a limit switch assigned to the electromagnet, is provided for magnetizing and demagnetizing the load, wherein the limit switch can be assigned to a suspension eye of the electromagnet.
  • the limit switch can be assigned to a suspension eye of the electromagnet.
  • the converter 1 is connected via choke coils 11 and fuses 3 to a three-phase source, not shown.
  • Lines 2 lead from the converter 1 via fuses 3 and direct current contactors 14 to electromagnets 5.
  • the direct current contactors 14 are connected to the limit switches 4, which are shown in FIGS.
  • the converter 1 is connected to its control 6 via ten parallel lines 2a, which in addition to a resistor 7 has a variable resistor 8, which enables an external controller setpoint specification.
  • To the converter 1 to the electromagnets 5 leading line 2 are connected behind the fuses 3 connecting lines 2b, which lead to double-running voltage measuring devices 10.
  • Other protective circuits for example with varistor freewheeling diodes and protective resistors, are also possible.
  • a thyristor block with a plurality of thyristors 12 with a corresponding phase angle (amplitude of the direct current) is driven.
  • the inner anti-parallel block is blocked.
  • the initially conductive outer block is blocked and the anti-parallel inner block is initially driven with the same phase angle.
  • the two thyristor blocks are now controlled alternately after the infinitely adjustable cycle times with increasing phase angle (smaller current amplitude) until the system is switched off after swinging out (see point 35 in FIG. 3).
  • a load beam 20 has a plurality of suspension eyes 21 through which bolts 22 of bearing eyes 23 of the electromagnets 5 are guided.
  • a limit switch 4 is attached to each suspension eye 21 in the lower region. After the electromagnets 5 have been placed on the object to be lifted, the load crossbeam 20 with the suspension eyes 21 and the limit switches 4 fastened thereon is further lowered, the limit switches 4 reaching the area of switching triggers 24 which are fastened to the bearing eyes 23 of the electromagnets 5 . Only when the limit switches 4 are in operative connection with the switching triggers 24 is the electromagnets and then the load can be lifted.
  • a main line 25 leads from the electromagnet 5 and a line 26 leads from each of the limit switches 4 to the converter 1 on the load beam 20.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Load-Engaging Elements For Cranes (AREA)

Abstract

A load transversal (20) has a plurality of suspension lugs (21) through which are guided bolts (22) of supporting eyes (23) of the electromagnets (5). A limit switch (4) is mounted in the lower region on each suspension lug (21). After the electromagnets (5) are placed on the object to be lifted, the load transversal (20) with the suspension lugs (21) and the limit switches (4) mounted thereon are further lowered, the limit switches (4) passing into the region of trip switches (24) which are mounted on the supporting eyes (23) of the electromagnets (5). Once the limit switches (4) are effectively connected to the trip switches (24), it is possible to switch on the electromagnets and thereafter to lift the load. It is not possible to switch off the electromagnets until the load is put down, when the limit switches (4) once again coincide with their relatively high trip switches (24). A main lead (25) leads from the electromagnet (5), and a lead (26) from each of the limit switches (4) to the rectifier (1) on the load transversal (20). <IMAGE>

Description

Die Erfindung betrifft ein Verfahren zum Entmagnetisieren von Stäh­len, die von einem Elektromagneten gehalten wurden, sowie eine An­ordnung zur Durchführung des Verfahrens.The invention relates to a method for demagnetizing steels, which were held by an electromagnet, and an arrangement for performing the method.

Bei einer Entmagnetisierungseinrichtung nach der DE-OS 32 38 609 wird der zu entmagnetisierende Gegenstand in axialer Richtung durch einen inneren Spulendurchlaß geführt. Für diesen Entmagnetisierungsvorgang ist eine zusätzliche Transportvorrichtung entweder für die Spule oder für den zu entmagnetisierenden Gegenstand sowie ein zusätzlicher Ar­beitsschritt erforderlich. Dieses Verfahren arbeitet mit Wechsel­spannung.In a demagnetization device according to DE-OS 32 38 609, the object to be demagnetized is guided in the axial direction through an inner coil passage. This demagnetization process requires an additional transport device either for the coil or for the object to be demagnetized, as well as an additional work step. This process works with AC voltage.

Bei einem Entmagnetisierungsverfahren nach der DE-OS 30 05 927 sind teure Kondensatoren für den Abbau der Wechselspannung erforderlich. Dieses Verfahren arbeitet mit abklingender Wechselspannung.In a demagnetization process according to DE-OS 30 05 927, expensive capacitors are required to reduce the AC voltage. This process works with decaying AC voltage.

Aufgabe der Erfindung ist es daher, ein einfaches Verfahren zum Ent­magnetisieren von Stählen zu schaffen, die von einem mit Gleichstrom erregten Elektromagneten gehalten wurden. Diese Aufgabe wird durch die Verfahrensschritte nach dem Hauptanspruch gelöst. Durch das Ein­schalten des Elektromagneten erst nach dem Anliegen an dem Stahl, kann die Position des Elektromagneten genau vorbestimmt werden und erfolgt nicht rein zufällig, wie es möglich ist, wenn der Elektromag­net den Stahl anzieht. Dies ist vor allem beim Spannen von Werkzeugen in Bearbeitungsmaschinen wichtig. Das Lösen des Elektromagneten er­folgt zwar erst nach dem Abschluß der Entmagnetisierung, die je nach Masse und Form des gehaltenen bzw. gehobenen Gegenstandes 10 bis 20 Sekunden beträgt. Dieser Zeitaufwand ist sehr gering im Verhältnis zum Entmagnetisierungsvorgang nach der DE-OS 32 38 609.The object of the invention is therefore to provide a simple method for demagnetizing steels which were held by an electromagnet excited with direct current. This object is achieved by the method steps according to the main claim. By switching on the electromagnet only after it has come into contact with the steel, the position of the electromagnet can be precisely predetermined and is not purely accidental, as is possible when the electromagnet attracts the steel. This is particularly important when clamping tools in processing machines. The electromagnet is only released after the demagnetization has been completed, depending on The mass and shape of the held or lifted object is 10 to 20 seconds. This expenditure of time is very small in relation to the demagnetization process according to DE-OS 32 38 609.

In weiterer Ausgestaltung des erfindungsgemäßen Verfahrens erfolgt das Entmagnetisieren durch abklingenden alternierenden Strom, dessen Amplitude und Taktzeiten einstellbar sind. Das Einstellen der Ampli­tuden und der Taktzeiten ist abhängig von der Legierung des Werk­stoffes sowie von der Masse und der Form des Werkstückes. Bei dem Verfahren ist es auch unwesentlich, ob z.B. ein dünnwandiges Rohr oder ein massives Werkstück gehoben bzw. gespannt wurde. Beim Entmag­netisieren ist jedoch wichtig, daß die erste Gegenschaltung genau so hoch (100 % der ursprünglichen) in der Erregung ist; erst dann erfolgt das gesteuerte Abklingen der Erregung. Zu Beginn des Entmagnetisierens erfolgt die Gegenschaltung in kleineren Stufen, die dann vergrößert werden (z.B. 100 %, 95 %, 90 %, 80 %, 60 %, 40 %, 20 %); dann erfolgt das Ausschwingen der Erregung, wobei Restfeldstärken von weniger als 10 Oe (Oersted) verbleiben.In a further embodiment of the method according to the invention, the demagnetization takes place by decaying alternating current, the amplitude and cycle times of which can be set. The setting of the amplitudes and cycle times depends on the alloy of the material as well as on the mass and shape of the workpiece. In the process, it is also immaterial whether e.g. a thin-walled tube or a solid workpiece has been lifted or clamped. When demagnetizing, however, it is important that the first counter circuit is just as high (100% of the original) in the excitation; only then does the controlled decay of the excitation take place. At the beginning of the demagnetization, the counter-switching takes place in smaller stages, which are then increased (e.g. 100%, 95%, 90%, 80%, 60%, 40%, 20%); then the excitement decays, leaving residual field strengths of less than 10 Oe (Oersted).

Bei einer Anordnung zur Durchführung des Verfahrens ist für das Mag­netisieren und Entmagnetisieren der Last eine von einem dem Elektro­magneten zugordneten Endschalter freigebbare gesteuerte, antipa­rallele Thyristorbrücke vorhanden, wobei der Endschalter einer Auf­hängeöse des Elektromagneten zugeordnet sein kann. Zum Heben langer Teile, z.B. von Rohren und Stäben, können mehrere Elektromagnete an einer Lasttraverse angeordnet sein, wobei dann jeder Elektromagnet einen eigenen Endschalter hat.In an arrangement for carrying out the method, a controlled, antiparallel thyristor bridge, which can be released by a limit switch assigned to the electromagnet, is provided for magnetizing and demagnetizing the load, wherein the limit switch can be assigned to a suspension eye of the electromagnet. For lifting long parts, e.g. of pipes and rods, several electromagnets can be arranged on a load beam, each electromagnet then having its own limit switch.

Das vollständige Entmagnetisieren der Werkstücke ist während deren Bearbeitung wichtig, damit die Werkstücke keine Späne anziehen, die beim erneuten Spannen der Werkstücke zwangsläufig zu einer ungenauen Positionierung führen. Auch führt ein Restmagnetismus in Nähe der Werkstücke zu ungenauen Anzeigeergebnissen von Meßgeräten und somit zum ungenauen Vermessen, was z.B. beim Arbeiten in Ölfeldanlagen schwerwiegende Folgen haben kann.The complete demagnetization of the workpieces is important during their processing so that the workpieces do not attract chips that when clamping the workpieces inevitably lead to inaccurate positioning. Residual magnetism in the vicinity of the workpieces also leads to inaccurate display results from measuring devices and thus to inaccurate measurement, which can have serious consequences, for example, when working in oilfield systems.

Ein Ausführungsbeispiel der Erfindung ist in den Zeichnungen darge­gestellt und im folgenden erläutert. Es zeigen:

  • Fig. 1 einen vereinfachten Schaltplan,
  • Fig. 2 einen Stromrichter aus Fig. 1, in größerem Maßstab,
  • Fig. 3 die Hüllkurven vom Abklingen der Erregung,
  • Fig. 4 die Taktzeiten zum Abklingen der Erregung,
  • Fig. 5 eine Aufhängung eines Lasthebemagneten in der Seitenan­sicht,
  • Fig. 6 die Aufhängung aus Fig. 5 in Richtung X.
An embodiment of the invention is shown in the drawings and explained below. Show it:
  • 1 is a simplified circuit diagram,
  • 2 shows a converter from FIG. 1, on a larger scale,
  • 3 shows the envelopes from the decay of the excitation,
  • 4 shows the cycle times for the decay of the excitation,
  • 5 is a suspension of a lifting magnet in side view,
  • 6 shows the suspension from FIG. 5 in the direction X.

Der Stromrichter 1 ist über Drosselspulen 11 und Sicherungen 3 an eine nicht gezeichnete Drehstromquelle angeschlossen. Vom Strom­richter 1 führen Leitungen 2 über Sicherungen 3 und Gleichstrom­schütze 14 zu Elektromagneten 5. Die Gleichstromschütze 14 sind über nicht gezeichnete Leitungen mit den Endschaltern 4 verbunden, die in Fig. 5 und 6 gezeichnet sind. Der Stromrichter 1 ist über zehn pa­rallele Leitungen 2a mit seiner Ansteuerung 6 verbunden, die außer einem Widerstand 7 einen veränderbaren Widerstand 8 hat, der eine externe Reglersollwertvorgabe ermöglicht. An die vom Stromrichter 1 zu den Elektromagneten 5 führenden Leitung 2 sind hinter den Sicherungen 3 Anschlußleitungen 2b angeschlossen, die zu doppelt ausgeführten Spannungsmeßgeräten 10 führen. In eine der Leitungen 2b ist ein Widerstand 7a und eine Sicherung 3a sowie ein kapazitiver Widerstand 9 angeordnet, der von einem Widerstand 7b überbrückbar ist. Andere Schutzbeschaltungen, z.B. mit Varistor-Freilaufdioden und Schutzwiderstände sind ebenfalls möglich.The converter 1 is connected via choke coils 11 and fuses 3 to a three-phase source, not shown. Lines 2 lead from the converter 1 via fuses 3 and direct current contactors 14 to electromagnets 5. The direct current contactors 14 are connected to the limit switches 4, which are shown in FIGS. The converter 1 is connected to its control 6 via ten parallel lines 2a, which in addition to a resistor 7 has a variable resistor 8, which enables an external controller setpoint specification. To the converter 1 to the electromagnets 5 leading line 2 are connected behind the fuses 3 connecting lines 2b, which lead to double-running voltage measuring devices 10. A resistor 7a and a fuse 3a as well as a capacitive resistor 9, which can be bridged by a resistor 7b, are arranged in one of the lines 2b. Other protective circuits, for example with varistor freewheeling diodes and protective resistors, are also possible.

Funktion der antiparallelen Thyrostorbrücke nach Fig. 2:Function of the anti-parallel Thyrostor bridge according to Fig. 2:

Beim Einschalten der Magnete wird ein Thyristorblock mit mehreren Thyristoren 12 mit entsprechendem Phasenwinkel (Amplitude des Gleichstroms) angesteuert. Der innere antiparallele Block ist ge­sperrt. Beim Ausschalten mit Entmagnetisieren wird der zunächst lei­tende äußere Block gesperrt, und der antiparallele innere Block wird mit zunächst dem gleichen Phasenwinkel angesteuert. Die beiden Thyristorblöcke werden nun abwechselnd nach den stufenlos einstell­baren Taktzeiten mit größer werdendem Phasenwinkel (kleinere Strom­amplitude) angesteuert, bis nach einem Ausschwingen (s. Punkt 35 in Fig. 3) die Anlage ausgeschaltet wird.When the magnets are switched on, a thyristor block with a plurality of thyristors 12 with a corresponding phase angle (amplitude of the direct current) is driven. The inner anti-parallel block is blocked. When switching off with demagnetization, the initially conductive outer block is blocked and the anti-parallel inner block is initially driven with the same phase angle. The two thyristor blocks are now controlled alternately after the infinitely adjustable cycle times with increasing phase angle (smaller current amplitude) until the system is switched off after swinging out (see point 35 in FIG. 3).

Die räumliche Anordnung der in Fig. 1 genannten Teile ist zum Teil in den Fig. 5 und 6 erkennbar. Eine Lasttraverse 20 hat mehrere Aufhän­geösen 21, durch die Bolzen 22 von Lageraugen 23 der Elektromagnete 5 geführt sind. An jeder Aufhängeöse 21 ist im unteren Bereich ein Endschalter 4 befestigt. Nach dem Aufsetzen der Elektromagnete 5 auf den zu hebenden Gegenstand wird die Lasttraverse 20 mit den Aufhän­geösen 21 und den daran befestigten Endschaltern 4 weiterhin abge­senkt, wobei die Endschalter 4 in den Bereich von Schaltauslösern 24 gelangen, die an den Lageraugen 23 der Elektromagnete 5 befestigt sind. Erst wenn die Endschalter 4 mit den Schaltauslösern 24 in Wirkverbindung stehen, ist das Einschalten der Elektromagnete und danach das Heben der Last möglich. Das Ausschalten der Elektromagnete ist ebenfalls erst nach dem Absetzen der Last möglich, wenn die End­schalter 4 wieder mit ihren relativ hohen Schaltauslösern 24 über­einstimmen. Vom Elektromagneten 5 führt eine Hauptleitung 25 und von jedem der Endschalter 4 eine Leitung 26 zum Stromrichter 1 auf der Lasttraverse 20.The spatial arrangement of the parts mentioned in FIG. 1 can be seen in part in FIGS. 5 and 6. A load beam 20 has a plurality of suspension eyes 21 through which bolts 22 of bearing eyes 23 of the electromagnets 5 are guided. A limit switch 4 is attached to each suspension eye 21 in the lower region. After the electromagnets 5 have been placed on the object to be lifted, the load crossbeam 20 with the suspension eyes 21 and the limit switches 4 fastened thereon is further lowered, the limit switches 4 reaching the area of switching triggers 24 which are fastened to the bearing eyes 23 of the electromagnets 5 . Only when the limit switches 4 are in operative connection with the switching triggers 24 is the electromagnets and then the load can be lifted. Switching off the electromagnets is also only possible after the load has been set off, when the limit switches 4 again match their relatively high switching triggers 24. A main line 25 leads from the electromagnet 5 and a line 26 leads from each of the limit switches 4 to the converter 1 on the load beam 20.

Die Fig. 3 und 4 zeigen den Verlauf der Hüllkurven 33 über die Spit­zen der Abklingkurven 34 während der Abklingzeit t. Er erreicht nach etwa 15 Sekunden die Null-Linie. Vom Aufsetzzeitpunkt 30 bis zum Einschaltzeitpunkt 31 ist die Erregung des Werkstückes nicht vorhan­den und liegt in der Null-Linie. Vom Einschaltzeitpunkt 31 bis zum Abschaltpunkt 32 hat die Erregung X des Werkstückes den höchsten Wert und klingt vom Abschaltzeitpunkt 32 nach dem Verlauf der Hüllkurven 33 ab. Die unterschiedliche, jeweils entgegengerichtete Einschalt­dauer ist in Fig. 4 erkennbar.3 and 4 show the course of the envelopes 33 over the peaks of the decay curves 34 during the decay time t. It reaches the zero line after about 15 seconds. From the point of attachment 30 to the point of switch-on 31, the excitation of the workpiece is absent and lies in the zero line. From the switch-on time 31 to the switch-off point 32, the excitation X of the workpiece has the highest value and decays from the switch-off time 32 according to the course of the envelopes 33. The different, opposing duty cycle can be seen in Fig. 4.

Claims (7)

1. Verfahren zum Entmagnetisieren von Stählen, die von einem Elek­tromagneten gehalten werden,
gekennzeichnet durch die folgenden Verfahrensschritte: a) das Einschalten des Elektromagneten erfolgt erst nach dem Anliegen an dem Stahl, b) Stahl Halten bzw. Heben, c) Last absetzen, d) Ausschalten des Elektromagneten mit Einleiten des Entmagne­tisierungsvorganges, e) Lösen des Elektromagneten nach Abschluß der Entmagnetisie­rung. 1. Method for demagnetizing steels held by an electromagnet
characterized by the following process steps: a) the electromagnet is only switched on after it has come into contact with the steel, b) holding or lifting steel, c) put down the load, d) switching off the electromagnet upon initiation of the demagnetization process, e) Loosen the electromagnet after demagnetization has been completed. 2. Verfahren nach Anspruch 1,
dadurch gekennzeichnet,
daß das Entmagnetisieren durch abklingenden alternierenden Strom erfolgt.2. The method according to claim 1,
characterized,
that the demagnetization takes place by decaying alternating current. 3. Verfahren nach Anspruch 2,
dadurch gekennzeichnet,
daß die Amplitude und die Taktzeiten stufenlos einstellbar sind.3. The method according to claim 2,
characterized,
that the amplitude and the cycle times are continuously adjustable. 4. Verfahren nach Anspruch 1,
dadurch gekennzeichnet,
daß der Entmagnetisierungsvorgang automatisch abläuft.4. The method according to claim 1,
characterized,
that the demagnetization process runs automatically. 5. Schaltungsanordnung zur Durchführung des Verfahrens nach einem oder mehreren der vorgenannten Ansprüche,
dadurch gekennzeichnet,
daß für das Magnetisieren und Entmagnetisieren der Last eine von einem dem Elektromagneten (5) zugeordneten Endschalter (4) freigebbare und gesteuerte antiparallele Thyristorbrücke (12) vorhanden ist.5. Circuit arrangement for performing the method according to one or more of the preceding claims,
characterized,
that for the magnetization and demagnetization of the load there is an antiparallel thyristor bridge (12) that can be released and controlled by a limit switch (4) assigned to the electromagnet (5). 6. Anordnung nach Anspruch 5,
dadurch gekennzeichnet,
daß der Endschalter (4) einer Aufhängung (21) (Lasche oder Kette) des Elektromagneten (5) zugeordnet ist.6. Arrangement according to claim 5,
characterized,
that the limit switch (4) of a suspension (21) (link or chain) of the electromagnet (5) is assigned. 7. Anordnung nach Anspruch 5 oder 6,
dadurch gekennzeichnet,
daß mehrere Elektromagnete (5) an einer Lasttraverse (20) ange­ordnet sind.7. Arrangement according to claim 5 or 6,
characterized,
that several electromagnets (5) are arranged on a load beam (20).
EP86730189A 1986-04-21 1986-11-11 Method and device for demagnetizing steel Withdrawn EP0243564A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3613714 1986-04-21
DE19863613714 DE3613714A1 (en) 1986-04-21 1986-04-21 METHOD AND DEVICE FOR THE DEMAGNETIZING OF STEELS

Publications (2)

Publication Number Publication Date
EP0243564A2 true EP0243564A2 (en) 1987-11-04
EP0243564A3 EP0243564A3 (en) 1988-01-07

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EP86730189A Withdrawn EP0243564A3 (en) 1986-04-21 1986-11-11 Method and device for demagnetizing steel

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DE (1) DE3613714A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0686984A1 (en) * 1994-06-09 1995-12-13 The Welding Institute Demagnetisation of materials

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DE102007009361B4 (en) * 2007-02-23 2012-02-16 Bundesrepublik Deutschland, vertr. d. d. Bundesministerium für Wirtschaft und Technologie, dieses vertr. d. d. Präsidenten der Physikalisch-Technischen Bundesanstalt Method and device for demagnetizing an object made of at least partially ferromagnetic material

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DE3005927A1 (en) * 1980-02-16 1981-09-03 Erich Dr.-Ing. 5300 Bonn Steingroever DEMAGNETIZING PROCEDURE
DD208263A1 (en) * 1981-10-29 1984-03-28 Klaus Liedloff ELECTRICAL CIRCUIT ARRANGEMENT FOR MAGNETIZING AND DETERMINING FERROMAGNETIC MATERIALS
DE3238609A1 (en) * 1982-10-19 1984-04-19 Eckart Dr.Rer.Nat. 2300 Kiel Hiss Demagnetisation device
DE3500011A1 (en) * 1985-01-02 1985-06-13 Axel R. Dr.-Ing. 5900 Siegen Hidde Method and arrangement for the regulated demagnetisation of rod-shaped, ferromagnetic and heat-treated semi-finished goods or finished goods in a continuous production process

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Publication number Priority date Publication date Assignee Title
DE3005927A1 (en) * 1980-02-16 1981-09-03 Erich Dr.-Ing. 5300 Bonn Steingroever DEMAGNETIZING PROCEDURE
DD208263A1 (en) * 1981-10-29 1984-03-28 Klaus Liedloff ELECTRICAL CIRCUIT ARRANGEMENT FOR MAGNETIZING AND DETERMINING FERROMAGNETIC MATERIALS
DE3238609A1 (en) * 1982-10-19 1984-04-19 Eckart Dr.Rer.Nat. 2300 Kiel Hiss Demagnetisation device
DE3500011A1 (en) * 1985-01-02 1985-06-13 Axel R. Dr.-Ing. 5900 Siegen Hidde Method and arrangement for the regulated demagnetisation of rod-shaped, ferromagnetic and heat-treated semi-finished goods or finished goods in a continuous production process

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0686984A1 (en) * 1994-06-09 1995-12-13 The Welding Institute Demagnetisation of materials

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EP0243564A3 (en) 1988-01-07
DE3613714A1 (en) 1987-10-22

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