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EP0929883B1 - Display element for use in a magnetic anti-theft system - Google Patents

Display element for use in a magnetic anti-theft system Download PDF

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Publication number
EP0929883B1
EP0929883B1 EP98944989A EP98944989A EP0929883B1 EP 0929883 B1 EP0929883 B1 EP 0929883B1 EP 98944989 A EP98944989 A EP 98944989A EP 98944989 A EP98944989 A EP 98944989A EP 0929883 B1 EP0929883 B1 EP 0929883B1
Authority
EP
European Patent Office
Prior art keywords
weight
alloy
strip
approximately
hard 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 - Lifetime
Application number
EP98944989A
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German (de)
French (fr)
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EP0929883A1 (en
Inventor
Hartwin Weber
Gernot Hausch
Ottmar Roth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vacuumschmelze GmbH and Co KG
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Vacuumschmelze GmbH and Co KG
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Publication of EP0929883A1 publication Critical patent/EP0929883A1/en
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    • GPHYSICS
    • G08SIGNALLING
    • G08BSIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00Burglar, theft or intruder alarms
    • G08B13/22Electrical actuation
    • G08B13/24Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2405Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used
    • G08B13/2408Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used using ferromagnetic tags
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/06Ferrous alloys, e.g. steel alloys containing aluminium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/08Ferrous alloys, e.g. steel alloys containing nickel
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/12Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/14Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • GPHYSICS
    • G08SIGNALLING
    • G08BSIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00Burglar, theft or intruder alarms
    • G08B13/22Electrical actuation
    • G08B13/24Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2428Tag details
    • G08B13/2437Tag layered structure, processes for making layered tags
    • G08B13/2442Tag materials and material properties thereof, e.g. magnetic material details
    • GPHYSICS
    • G08SIGNALLING
    • G08BSIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00Burglar, theft or intruder alarms
    • G08B13/22Electrical actuation
    • G08B13/24Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2428Tag details
    • G08B13/2437Tag layered structure, processes for making layered tags
    • G08B13/2445Tag integrated into item to be protected, e.g. source tagging
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047Alloys characterised by their composition
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/147Alloys characterised by their composition
    • H01F1/14708Fe-Ni based alloys
    • H01F1/14716Fe-Ni based alloys in the form of sheets
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1216Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
    • C21D8/1222Hot rolling
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1216Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
    • C21D8/1233Cold rolling
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1244Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest
    • C21D8/1261Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest following hot rolling
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1244Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest
    • C21D8/1266Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest between cold rolling steps
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00Stock material or miscellaneous articles
    • Y10S428/90Magnetic feature
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00Stock material or miscellaneous articles
    • Y10S428/922Static electricity metal bleed-off metallic stock
    • Y10S428/9265Special properties
    • Y10S428/928Magnetic property
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/12All metal or with adjacent metals
    • Y10T428/12465All metal or with adjacent metals having magnetic properties, or preformed fiber orientation coordinate with shape
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/12All metal or with adjacent metals
    • Y10T428/12493Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12639Adjacent, identical composition, components
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/12All metal or with adjacent metals
    • Y10T428/12493Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12639Adjacent, identical composition, components
    • Y10T428/12646Group VIII or IB metal-base
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/12All metal or with adjacent metals
    • Y10T428/12493Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12639Adjacent, identical composition, components
    • Y10T428/12646Group VIII or IB metal-base
    • Y10T428/12653Fe, containing 0.01-1.7% carbon [i.e., steel]
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/12All metal or with adjacent metals
    • Y10T428/12493Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12771Transition metal-base component
    • Y10T428/12861Group VIII or IB metal-base component
    • Y10T428/12951Fe-base component
    • Y10T428/12958Next to Fe-base component
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/12All metal or with adjacent metals
    • Y10T428/12493Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12986Adjacent functionally defined components

Definitions

  • Such magnetic anti-theft systems and indicators are well known and for example in the EP 0 121 649 B1 or described in detail in WO 90/03652.
  • magnetoelastic systems in which the activation strip for activating the alarm strip serves by magnetization
  • harmonics Systems in which the activation strip according to its Magnetization serves to deactivate the alarm strip.
  • Alloys with semi-hard magnetic properties that are used for the bias strips Co-Fe-V alloys known as VICALLOY, Co-Fe-Ni alloys, known as VACOZET, as well as Fe-Co-Cr alloys.
  • VICALLOY Co-Fe-V alloys
  • VACOZET Co-Fe-Ni alloys
  • Fe-Co-Cr alloys Fe-Co-Cr alloys.
  • These well-known semi-hard magnetic alloys contain high proportions of cobalt, some of them at least 45 wt .-% and are accordingly expensive.
  • these alloys are magnetically final annealed Condition brittle so that they do not have sufficient ductility, to meet the requirements for the display elements for Anti-theft systems adequately.
  • An important requirement is that these activation strips insensitive to bending or deformation have to be.
  • the remanence under bending or tensile load should be as possible be small. As a guideline, a change becomes smaller 20% specified.
  • the object of the present invention is therefore to begin with mentioned display elements with regard to their bias strips to develop further in that the above Requirements are met.
  • this object is achieved in that the Pre-magnetization strips made from a semi-hard magnetic alloy consist of 8 to 25 wt .-% nickel, 1.5 to 4.5 % By weight aluminum, 0.5 to 3% by weight titanium and balance iron is.
  • the alloy can also contain 0 to 5% by weight of cobalt and / or 0 up to 3% by weight of molybdenum or chromium and / or at least one of the elements Zr, Hf, V, Nb, Ta, W, Mn, Si in individual Proportions of less than 0.5% by weight of the alloy and in one Total content of less than 1% by weight of the alloy and / or at least one of the elements C, N, S, P, B, H, O in individual proportions of less than 0.2% by weight of the alloy and in a total proportion of less than 1% by weight of the Alloy included.
  • the alloy is characterized by a coercive force H c of 10 to 24 A / cm and a remanence B r of at least 1.3 T (13,000 gaus).
  • the alloys of the invention are highly ductile and excellent cold workability before starting, so that cross-sectional reductions of more than 90% are also possible are.
  • Magnetic strips can be made from such alloys are produced, in particular by cold rolling, which Have thicknesses of less than 0.05 mm. Also stand out the alloys of the invention by excellent magnetic Properties and characterized by corrosion resistance.
  • a particularly advantageous alloy is a semi-hard magnetic Iron alloy according to the present invention, the 13.0 to 17.0 wt% nickel, 1.8 to 2.8 % By weight of aluminum and 0.5 to 1.5% by weight of titanium. Reducing the aluminum content can in particular the magnetostriction can be set particularly favorably.
  • the bias strips are through Melt the alloy under vacuum and pour into one Cast block made. Then the ingot becomes one Hot rolled strip at temperatures above 800 ° C, then at annealed at a temperature above 800 ° C and then cooled down quickly. After cold working, expediently Cold rolling in accordance with a reduction in cross section 90% is followed by intermediate annealing at approx. 700 ° C. Cold forming then takes place, expediently Cold rolling, corresponding to a reduction in cross section of at least 60%, preferably 75% or higher, instead. As The last step is the cold rolled strip at temperatures tempered from approx. 400 ° C to 600 ° C. After that, the bias strips cut to length.
  • the ratio of the saturation for a given low magnetization field strength of, for example, 40 A / cm to the saturation B f for a magnetic field in the kOe range should be almost 1, which can be seen from FIG. 3.
  • the counter-field stability should be such that the remanence B S still retains at least 80% of its original value after a counter-field demagnetization of a few A / cm.
  • the remanence B r should only keep 20% of the original value.
  • the display elements must be such that they do not change their remanence B r very much in the vicinity of the coils in the detection locks as a result of a field which is elevated there and possibly oriented in the opposite direction.
  • the alloys according to the invention have such a required counter field stability.
  • the alloys of the present invention are typically by casting a melt from the alloy components in a crucible or oven under vacuum or under a protective gas atmosphere.
  • the temperatures are at about 1600 ° C.
  • the casting is typically done in a round mold.
  • the Cast ingots made from the present alloys then become typical through hot working, intermediate annealing, cold working and further intermediate annealing.
  • the intermediate glow takes place for the purpose of homogenization, grain refinement, deformation or the development of desirable mechanical properties, especially high ductility.
  • Heat treatment at preferably temperatures above 800 ° C, rapid cooling and starting.
  • Preferred tempering temperatures are around 400 ° C to 600 ° C and the starting times are typical from one minute to 24 hours.
  • Alloys are especially cold worked a reduction in cross section of at least 60% before Starting possible.
  • Example 2 An alloy with 15.0% by weight of nickel, 3.0% by weight of aluminum, 1.2% by weight of titanium and the rest of iron was processed as in Example 1, but with a final intermediate annealing at 700 ° C, one last cold deformation corresponding to a cross-sectional reduction of 70% and a final annealing at 500 ° C.
  • a coercive force H c equal to 21 A / cm and a remanence B r equal to 1.45 T were measured.
  • Example 2 An alloy with 15.0% by weight of nickel, 3.0% by weight of aluminum, 1.2% by weight of titanium and the rest of iron was produced as in Example 2. Deviating from this, the last intermediate annealing was carried out at 650 ° C, the last cold working corresponding to a cross-sectional reduction of 85% and the tempering treatment at 480 ° C. A coercive force H c equal to 20 A / cm and a remanence B r equal to 1.53 T were measured.
  • Example 2 An alloy with 15.0% by weight of nickel, 3.0% by weight of aluminum, 1.2% by weight of titanium, 2.0% by weight of molybdenum and the rest of iron was produced as in Example 2. After an annealing treatment at 480 ° C, a coercive force H c equal to 20 A / cm and a remanence B r equal to 1.56 T were measured.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electromagnetism (AREA)
  • Automation & Control Theory (AREA)
  • Computer Security & Cryptography (AREA)
  • General Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Dispersion Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Hard Magnetic Materials (AREA)
  • Manufacturing Of Steel Electrode Plates (AREA)
  • Soft Magnetic Materials (AREA)
  • Burglar Alarm Systems (AREA)

Abstract

The invention relates to a medium-hard magnetic alloy for use in magnetic anti-theft systems, containing between 8 and 25 weight % Ni, between 1.5 and 4.5 weight % Al and between 0.5 and 3 weight % Ti, the remainder being made up of Fe. The alloy differs from known, used alloys in that it has excellent magnetic properties and high corrosion resistance. The alloy provided for in the invention is also extremely well suited for cold working before tempering.

Description

Die Erfindung betrifft ein Anzeigeelement für die Verwendung in einem magnetischen Diebstahlsicherungssystem bestehend aus:

  • 1. Einem länglichen, aus einer amorphen ferromagnetischen Legierung bestehenden Alarmstreifen und zumindest
  • 2. einem aus einer halbhartmagnetischen Legierung bestehenden Aktivierungsstreifen.
  • The invention relates to a display element for use in a magnetic anti-theft system consisting of:
  • 1. An elongated alarm strip made of an amorphous ferromagnetic alloy and at least
  • 2. an activation strip consisting of a semi-hard magnetic alloy.
  • Solche magnetischen Diebstahlsicherungssysteme und Anzeigeelemente sind hinlänglich bekannt und beispielsweise in der EP 0 121 649 B1 bzw. in der WO 90/03652 eingehend beschrieben. Zum einen gibt es magnetoelastische Systeme, bei denen der Aktivierungsstreifen zur Aktivierung des Alarmstreifens durch Aufmagnetisierung dient, zum anderen gibt es harmonische Systeme, bei denen der Aktivierungsstreifen nach seiner Aufmagnetisierung zur Deaktivierung des Alarmstreifens dient.Such magnetic anti-theft systems and indicators are well known and for example in the EP 0 121 649 B1 or described in detail in WO 90/03652. On the one hand there are magnetoelastic systems in which the activation strip for activating the alarm strip serves by magnetization, on the other hand there are harmonics Systems in which the activation strip according to its Magnetization serves to deactivate the alarm strip.

    Zu den Legierungen mit halbhartmagnetischen Eigenschaften, die für die Vormagnetisierungsstreifen verwendet werden, gehören Co-Fe-V-Legierungen, die als VICALLOY bekannt sind, Co-Fe-Ni-Legierungen, die als VACOZET bekannt sind, sowie Fe-Co-Cr-Legierungen. Diese bekannten halbhartmagnetischen Legierungen enthalten hohe Kobaltanteile zum Teil von mindestens 45 Gew.-% und sind dementsprechend teuer.Alloys with semi-hard magnetic properties, that are used for the bias strips Co-Fe-V alloys known as VICALLOY, Co-Fe-Ni alloys, known as VACOZET, as well as Fe-Co-Cr alloys. These well-known semi-hard magnetic alloys contain high proportions of cobalt, some of them at least 45 wt .-% and are accordingly expensive.

    Ferner sind diese Legierungen im magnetisch schlußgeglühten Zustand spröde, so daß sie keine ausreichende Duktilität aufweisen, um den Anforderungen bei den Anzeigeelementen für Diebstahlsicherungssystemen ausreichend gerecht zu werden. Eine wichtige Anforderung ist nämlich, daß diese Aktivierungsstreifen gegenüber Verbiegungen bzw. Verformungen unempfindlich sein müssen. Furthermore, these alloys are magnetically final annealed Condition brittle so that they do not have sufficient ductility, to meet the requirements for the display elements for Anti-theft systems adequately. An important requirement is that these activation strips insensitive to bending or deformation have to be.

    Ferner geht man mittlerweile dazu über, die Anzeigeelemente bei Diebstahlsicherungssystemen direkt in das zu sicherende Produkt einzubringen (Source-Tagging). Dadurch ergibt sich zusätzlich die Anforderung, daß die halbhartmagnetischen Legierungen auch aus größerer Entfernung bzw. mit kleineren Feldern aufmagnetisiert werden können. Es hat sich gezeigt, daß die Koerzitivkraft Hc auf Werte von höchstens 24 A/cm eingeschränkt werden muß.Furthermore, there is now a move to incorporate the display elements in theft protection systems directly into the product to be secured (source tagging). This also results in the requirement that the semi-hard magnetic alloys can also be magnetized from a greater distance or with smaller fields. It has been shown that the coercive force H c must be restricted to values of at most 24 A / cm.

    Andererseits wird aber auch eine ausreichende Gegenfeldstabilität gefordert, wodurch der untere Grenzwert der Koerzitivkraft festgelegt wird. Hierbei sind nur Koerzitivkräfte von mindestens 10 A/cm geeignet.On the other hand, there is also sufficient stability in the opposite field required, causing the lower limit of the coercive force is set. Here are only coercive forces from suitable at least 10 A / cm.

    Ferner soll die Remanenz unter Biege- bzw. Zugbelastung möglichst gering sein. Als Richtwert wird eine Änderung kleiner 20 % vorgegeben.Furthermore, the remanence under bending or tensile load should be as possible be small. As a guideline, a change becomes smaller 20% specified.

    Aufgabe der vorliegenden Erfindung ist es daher, die eingangs genannten Anzeigeelemente bezüglich ihrer Vormagnetisierungsstreifen dahingehend weiter zu entwickeln, daß die oben genannten Anforderungen erfüllt werden.The object of the present invention is therefore to begin with mentioned display elements with regard to their bias strips to develop further in that the above Requirements are met.

    Erfindungsgemäß wird diese Aufgabe dadurch gelöst, daß die Vormagnetisierungsstreifen aus einer halbhartmagnetischen Legierung bestehen, die aus 8 bis 25 Gew.-% Nickel, 1,5 bis 4,5 Gew.-% Aluminium, 0,5 bis 3 Gew.-% Titan und Rest Eisen zusammengesetzt ist.According to the invention this object is achieved in that the Pre-magnetization strips made from a semi-hard magnetic alloy consist of 8 to 25 wt .-% nickel, 1.5 to 4.5 % By weight aluminum, 0.5 to 3% by weight titanium and balance iron is.

    Die Legierung kann ferner 0 bis 5 Gew.-% Kobalt und/oder 0 bis 3 Gew.-% Molybdän oder Chrom und/oder wenigstens eines der Elemente Zr, Hf, V, Nb, Ta, W, Mn, Si in individuellen Anteilen von weniger als 0,5 Gew.-% der Legierung und in einem Gesamtanteil von weniger als 1 Gew.-% der Legierung und/oder wenigstens eines der Elemente C, N, S, P, B, H, O in individuellen Anteilen von weniger als 0,2 Gew.-% der Legierung und in einem Gesamtanteil von weniger als 1 Gew.-% der Legierung enthalten.The alloy can also contain 0 to 5% by weight of cobalt and / or 0 up to 3% by weight of molybdenum or chromium and / or at least one of the elements Zr, Hf, V, Nb, Ta, W, Mn, Si in individual Proportions of less than 0.5% by weight of the alloy and in one Total content of less than 1% by weight of the alloy and / or at least one of the elements C, N, S, P, B, H, O in individual proportions of less than 0.2% by weight of the alloy and in a total proportion of less than 1% by weight of the Alloy included.

    Die Legierung ist durch eine Koerzitivkraft Hc von 10 bis 24 A/cm und eine Remanenz Br von mindestens 1,3 T (13.000 Gaus) gekennzeichnet.The alloy is characterized by a coercive force H c of 10 to 24 A / cm and a remanence B r of at least 1.3 T (13,000 gaus).

    Die erfindungsgemaßen Legierungen sind in hohem Maße duktil und hervorragend vor dem Anlassen kalt verformbar, so daß auch Querschnittsverringerungen von mehr als 90 % möglich sind. Aus solchen Legierungen können Vormagnetisierungsstreifen hergestellt werden, insbesondere durch Kaltwalzen, die Dicken von kleiner 0,05 mm aufweisen. Ferner zeichnen sich die erfindungsgemäßen Legierungen durch exzellente magnetische Eigenschaften und durch Korrosionsbeständigkeit aus.The alloys of the invention are highly ductile and excellent cold workability before starting, so that cross-sectional reductions of more than 90% are also possible are. Magnetic strips can be made from such alloys are produced, in particular by cold rolling, which Have thicknesses of less than 0.05 mm. Also stand out the alloys of the invention by excellent magnetic Properties and characterized by corrosion resistance.

    Eine ganz besonders vorteilhafte Legierung ist eine halbhartmagnetische Eisenlegierung gemäß der vorliegenden Erfindung, die 13,0 bis 17,0 Gew.-% Nickel, 1,8 bis 2,8 Gew.-% Aluminium sowie 0,5 bis 1,5 Gew.-% Titan enthält. Durch die Verringerung des Aluminiumgehalts kann insbesondere die Magnetostriktion besonders günstig eingestellt werden.A particularly advantageous alloy is a semi-hard magnetic Iron alloy according to the present invention, the 13.0 to 17.0 wt% nickel, 1.8 to 2.8 % By weight of aluminum and 0.5 to 1.5% by weight of titanium. Reducing the aluminum content can in particular the magnetostriction can be set particularly favorably.

    Typischerweise werden die Vormagnetisierungsstreifen durch Erschmelzen der Legierung unter Vacuum und Gießen zu einem Gußblock hergestellt. Anschließend wird der Gußblock zu einem Band bei Temperaturen oberhalb 800°C warmgewalzt, danach bei einer Temperatur von oberhalb 800°C zwischengeglüht und danach schnell abgekühlt. Nach einer Kaltverformung, zweckmäßigerweise Kaltwalzen entsprechend einer Querschnittsverringerung von ca. 90 % folgt eine Zwischenglühung bei ca. 700°C. Anschließend findet eine Kaltverformung, zweckmäßigerweise Kaltwalzen, entsprechend einer Querschnittsverringerung von mindestens 60 % vorzugsweise 75 % oder höher, statt. Als letzter Schritt wird das kaltgewalzte Band bei Temperaturen von ca. 400°C bis 600°C angelassen. Danach werden die Vormagnetisierungsstreifen abgelängt. Typically, the bias strips are through Melt the alloy under vacuum and pour into one Cast block made. Then the ingot becomes one Hot rolled strip at temperatures above 800 ° C, then at annealed at a temperature above 800 ° C and then cooled down quickly. After cold working, expediently Cold rolling in accordance with a reduction in cross section 90% is followed by intermediate annealing at approx. 700 ° C. Cold forming then takes place, expediently Cold rolling, corresponding to a reduction in cross section of at least 60%, preferably 75% or higher, instead. As The last step is the cold rolled strip at temperatures tempered from approx. 400 ° C to 600 ° C. After that, the bias strips cut to length.

    Im folgenden ist die Erfindung anhand der Zeichnung im einzelnen beschrieben. Dabei zeigen:

    Figur 1
    das Entmagnetisierungsverhalten von Fe-Ni-Al-Ti-Legierungen nach einer Wechselfeldentmagnetisierung bei 4 A/cm in Abhängigkeit von der Koerzitivkraft,
    Figur 2
    das Entmagnetisierungsverhalten von Fe-Ni-Al-Ti-Legierungen nach einer Wechselfeldentmagnetisierung bei 20 A/cm in Abhängigkeit von der Koerzitivkraft,
    Figur 3
    die Änderung der Remanenz unter Zugspannung im Vergleich zu einer Legierung nach dem Stand der Technik und
    Figur 4
    die relative Änderung des magnetischen Flusses in % % bei verschiedenen Koerzitivfeldstärken nach mechanischer Verformung im Vergleich zu einer Legierung nach dem Stand der Technik.
    The invention is described in detail below with reference to the drawing. Show:
    Figure 1
    the demagnetization behavior of Fe-Ni-Al-Ti alloys after an alternating field demagnetization at 4 A / cm depending on the coercive force,
    Figure 2
    the demagnetization behavior of Fe-Ni-Al-Ti alloys after an alternating field demagnetization at 20 A / cm depending on the coercive force,
    Figure 3
    the change in the remanence under tension compared to an alloy according to the prior art and
    Figure 4
    the relative change in the magnetic flux in%% at different coercive field strengths after mechanical deformation in comparison to an alloy according to the prior art.

    Für die Tauglichkeit einer Legierung für einen Aktivierungsstreifen in einem Diebstahlsicherungssystem, insbesondere für sogenannte "Source-Tagging", ergeben sich folgende Forderungen:For the suitability of an alloy for an activation strip in an anti-theft system, especially for So-called "source tagging", the following requirements result:

    Die Änderung der Remanenz unter Biege- bzw. Zugbelastung soll möglichst gering sein. Als Richtwert wird eine Änderung kleiner 20 % vorgegeben. Wie aus der Figur 3 zu ersehen ist, werden mit den Legierungen nach der vorliegenden Erfindung Werte ≤ 10 % erreicht.The change in remanence under bending or tensile load should be as low as possible. As a guideline, a change becomes smaller 20% specified. As can be seen from Figure 3, values with the alloys of the present invention ≤ 10% reached.

    Aus der Figur 4 ergibt sich, daß neben der Legierung auch die Koerzitivfeldstärke und der Biegeradius die Änderung des Flusses bestimmen. Die Legierungen gemäß der vorliegenden Erfindung erreichen bei entsprechenden Koerzitivfeldstärken bei Biegeradien ≥ 12 mm Werte < 5 % bzw. bei Biegeradien ≥ 4 mm Werte < 10 % und Dicken von ca. 50 µm.From Figure 4 it follows that in addition to the alloy Coercivity and the bending radius change the Determine the river. The alloys according to the present invention achieve with corresponding coercive field strengths Bending radii ≥ 12 mm values <5% or with bending radii ≥ 4 mm Values <10% and thicknesses of approx. 50 µm.

    Das Verhältnis der Sättigung bei gegebener geringer Aufmagnetisierungsfeldstärke von z.B. 40 A/cm zur Sättigung Bf bei einem Magnetfeld im kOe-Bereich soll nahezu 1 sein, was aus der Figur 3 zu ersehen ist.The ratio of the saturation for a given low magnetization field strength of, for example, 40 A / cm to the saturation B f for a magnetic field in the kOe range should be almost 1, which can be seen from FIG. 3.

    Die Gegenfeldstabilität soll derart beschaffen sein, daß die Remanenz BS nach einer Gegenfeldentmagnetisierung von wenigen A/cm immer noch mindestens 80 % ihres ursprünglichen Wertes beibehält.The counter-field stability should be such that the remanence B S still retains at least 80% of its original value after a counter-field demagnetization of a few A / cm.

    Schließlich soll die Remanenz Br nach einem Entmagnetisierungszyklus mit einem vorgegebenen Magnetfeld lediglich 20 % vom ursprünglichen Wert behalten.Finally, after a demagnetization cycle with a given magnetic field, the remanence B r should only keep 20% of the original value.

    Im einzelnen bedeutet das, daß eine Aufmagnetisierung des Aktivierungsstreifens, d. h. eine Aktivierung/Deaktivierung des Anzeigeelementes, auch vor Ort erfolgen kann. Dort stehen aber in der Regel nur sehr kleine Felder zur Verfügung. Die erreichte Sättigung soll sich nur wenig von dem Wert bei hohen Aufmagnetisierungsfeldern unterscheiden, um gleiches Verhalten der Anzeigeelemente zu garantieren.Specifically, this means that magnetization of the activation strip d. H. an activation / deactivation of the Display element, can also be done on site. Stand there but usually only very small fields are available. The Saturation achieved is said to differ only slightly from the value at high Magnetizing fields differ in order to have the same behavior guarantee the display elements.

    Die Anzeigeelemente müssen so beschaffen sein, daß sie in der Nähe der Spulen in den Detektionsschleusen in Folge eines dort erhöhten und eventuellen in Gegenrichtung orientierten Feldes nur wenig ihre Remanenz Br ändern. Wie aus der Figur 1 zu sehen ist, weisen die erfindungsgemäßen Legierungen eine solche geforderte Gegenfeldstabilität auf.The display elements must be such that they do not change their remanence B r very much in the vicinity of the coils in the detection locks as a result of a field which is elevated there and possibly oriented in the opposite direction. As can be seen from FIG. 1, the alloys according to the invention have such a required counter field stability.

    Schließlich müssen die Anzeigeelemente sich mit relativ kleinen Feldern entmagnetisieren lassen, d.h. bei magnetoelastischen Anzeigeelementen deaktivieren bzw. bei harmonischen Anzeigeelementen aktivieren, lassen. Die Figur 2 veranschaulicht diese Zusammenhänge bei den erfindungsgemäßen Legierungen.Finally, the display elements need to be relatively small Allow fields to demagnetize, i.e. with magnetoelastic Deactivate display elements or for harmonic display elements activate, leave. Figure 2 illustrates these relationships in the alloys according to the invention.

    Die gleichzeitige Erfüllung der zuletzt genannten drei Forderungen ergibt für die zugänglichen Bereiche der Koerzitivkräfte Hc sehr starke Einschränkungen, da die drei Forderungen gegenläufig sind.The simultaneous fulfillment of the last three requirements mentioned results in very strong restrictions for the accessible areas of the coercive forces H c , since the three requirements are opposed.

    Die Legierungen nach der vorliegenden Erfindung werden typischerweise durch Gießen einer Schmelze aus den Legierungsbestandteilen in einem Tiegel oder Ofen unter Vacuum oder unter einer Schutzgasatmosphäre hergestellt. Die Temperaturen liegen dabei bei ca. 1600°C.The alloys of the present invention are typically by casting a melt from the alloy components in a crucible or oven under vacuum or under a protective gas atmosphere. The temperatures are at about 1600 ° C.

    Der Abguß erfolgt typischerweise in eine Rundkokille. Die Gußbarren aus den vorliegenden Legierungen werden dann typischerweise durch Warmverformung, Zwischenglühen, Kaltverformung und weiteren Zwischenglühen bearbeitet. Das Zwischenglühen erfolgt zwecks Homogenisierung, Kornverfeinerung, Verformung oder der Ausbildung wünschenswerter mechanischer Eigenschaften, insbesondere einer hohen Duktilität.The casting is typically done in a round mold. The Cast ingots made from the present alloys then become typical through hot working, intermediate annealing, cold working and further intermediate annealing. The intermediate glow takes place for the purpose of homogenization, grain refinement, deformation or the development of desirable mechanical properties, especially high ductility.

    Eine hervorragende Struktur wird beispielsweise durch folgende Bearbeitung erreicht:An excellent structure is, for example, by the following Processing reached:

    Warmbehandlung bei vorzugsweise Temperaturen oberhalb 800°C, schnelles Abkühlen und Anlassen. Bevorzugte Anlaßtemperaturen liegen bei 400°C bis 600°C und die Anlaßzeiten typischerweise bei einer Minute bis 24 Stunden. Mit den erfindungsgemäßen Legierungen ist insbesondere eine Kaltverformung entsprechend einer Querschnittsverringerung von mindestens 60 % vor dem Anlassen möglich.Heat treatment at preferably temperatures above 800 ° C, rapid cooling and starting. Preferred tempering temperatures are around 400 ° C to 600 ° C and the starting times are typical from one minute to 24 hours. With the invention Alloys are especially cold worked a reduction in cross section of at least 60% before Starting possible.

    Durch den Schritt des Anlassens wird die Koerzitivkraft und die Rechteckigkeit der magnetischen B-H-Schleife erhöht, was für die Anforderungen an Vormagnetisierungsstreifen wesentlich ist. Through the step of tempering, the coercive force and the squareness of the magnetic B-H loop increases what essential for the requirements for bias strips is.

    Das Herstellverfahren für besonders gute Vormagnetisierungsstreifen umfaßt folgende Schritte:

  • 1. Gießen bei 1600°C
  • 2. Warmwalzen des Gußblocks bei Temperatur oberhalb 800°C
  • 3. Mehrstündiges Zwischenglühen bei größer 800°C mit Abschreckung in Wasser
  • 4. Kaltwalzen entsprechend einer Querschnittsverringerung von ca. 90 %
  • 5. Kaltverformen entsprechend einer Querschnittsverringerung von ca. 90 %
  • 6. Zwischenglühen bei ca. 700°C
  • 7. Mehrstündiges Zwischenglühen bei ca. 700°C
  • 8. Kaltverformen entsprechend einer Querschnittsverringerung von ca. 70 %
  • 9. Mehrstündiges Anlassen bei ca. 480°C
  • 10. Schneiden und Ablängen der Aktivierungsstreifen.
  • The manufacturing process for particularly good bias strips comprises the following steps:
  • 1. Pour at 1600 ° C
  • 2. Hot rolling the ingot at a temperature above 800 ° C
  • 3. Intermediate annealing at 800 ° C for several hours with quenching in water
  • 4. Cold rolling corresponding to a cross-sectional reduction of approx. 90%
  • 5. Cold forming corresponding to a reduction in cross section of approx. 90%
  • 6. Intermediate annealing at approx. 700 ° C
  • 7. Intermediate annealing at approx. 700 ° C for several hours
  • 8. Cold forming corresponding to a reduction in cross section of approx. 70%
  • 9. Tempering for several hours at approx. 480 ° C
  • 10. Cutting and cutting the activation strips.
  • Mit diesen Verfahren wurden Aktivierungsstreifen hergestellt, die eine ausgezeichnete Koerzitivkraft Hc und eine sehr gute Remanenz Br aufwiesen. Die Magnetisierungseigenschaften und die Gegenfeldstabilität waren hervorragend.With these methods, activation strips were produced which had an excellent coercive force H c and a very good remanence B r . The magnetization properties and the counter field stability were excellent.

    Die Herstellung von Fe-Ni-Al-Ti-Aktivierungsstreifen der in Rede stehenden Art ist nun anhand der folgenden Beispiele eingehend beschrieben:The production of Fe-Ni-Al-Ti activation strips of the in The type in question is now based on the following examples described in detail:

    Beispiel 1:Example 1:

    Eine Legierung mit 18,0 Gew.-% Nickel, 3,8 Gew.-% Aluminium, 1,0 Gew.-% Titan und Rest Eisen wurden unter Vacuum erschmolzen. Der resultierende Gußbarren wurde bei ca. 1000°C warmgewalzt, bei 1100°C für eine Stunde zwischengeglüht und in Wasser schnell abgekühlt. Nach einem anschließenden Kaltwalzen mit einer Querschnittsverringerung von 80 % wurde das resultierende Band nochmals bei 1100°C für eine Stunde zwischengeglüht und in Wasser schnell abgekühlt. Nach einem weiteren Kaltverformen mit einer Querschnittsverringerung von 50 % wurde das Band bei 650°C für vier Stunden zwischengeglüht. Entsprechend einer Querschnittsverringerung von 90 % wurde das Band danach kaltgewalzt und für drei Stunden bei 520°C angelassen und an Luft gekühlt. Es wurde eine Koerzitivkraft Hc gleich 23 A/cm sowie eine Remanenz Br gleich 1,48 T gemessen.An alloy with 18.0% by weight of nickel, 3.8% by weight of aluminum, 1.0% by weight of titanium and the rest of iron were melted under vacuum. The resulting cast ingot was hot rolled at about 1000 ° C, annealed at 1100 ° C for one hour and quickly cooled in water. After a subsequent cold rolling with a cross-sectional reduction of 80%, the resulting strip was again annealed at 1100 ° C for one hour and quickly cooled in water. After a further cold working with a cross-section reduction of 50%, the strip was annealed at 650 ° C for four hours. In accordance with a reduction in cross-section of 90%, the strip was then cold rolled and tempered for three hours at 520 ° C. and cooled in air. A coercive force H c equal to 23 A / cm and a remanence B r equal to 1.48 T were measured.

    Beispiel 2:Example 2:

    Eine Legierung mit 15,0 Gew.-% Nickel, 3,0 Gew.-% Aluminium, 1,2 Gew.-% Titan und Rest Eisen wurden wie nach Beispiel 1 bearbeitet, jedoch mit einer letzten Zwischenglühung bei 700°C, einer letzten Kaltverformung entsprechend einer Querschnittsverringerung von 70 % sowie einer Schlußglühung bei 500°C. Es wurde eine Koerzitivkraft Hc gleich 21 A/cm und eine Remanenz Br gleich 1,45 T gemessen.An alloy with 15.0% by weight of nickel, 3.0% by weight of aluminum, 1.2% by weight of titanium and the rest of iron was processed as in Example 1, but with a final intermediate annealing at 700 ° C, one last cold deformation corresponding to a cross-sectional reduction of 70% and a final annealing at 500 ° C. A coercive force H c equal to 21 A / cm and a remanence B r equal to 1.45 T were measured.

    Beispiel 3:Example 3:

    Es wurde eine Legierung mit 15,0 Gew.-% Nickel, 3,0 Gew.-% Aluminium, 1,2 Gew.-% Titan und Rest Eisen wie in Beispiel 2 hergestellt. Abweichend davon erfolgte die letzte Zwischenglühung bei 650°C, die letzte Kaltverformung entsprechend einer Querschnittsverringerung von 85 % und die Anlaßbehandlung bei 480°C. Es wurde eine Koerzitivkraft Hc gleich 20 A/cm und eine Remanenz Br gleich 1,53 T gemessen.An alloy with 15.0% by weight of nickel, 3.0% by weight of aluminum, 1.2% by weight of titanium and the rest of iron was produced as in Example 2. Deviating from this, the last intermediate annealing was carried out at 650 ° C, the last cold working corresponding to a cross-sectional reduction of 85% and the tempering treatment at 480 ° C. A coercive force H c equal to 20 A / cm and a remanence B r equal to 1.53 T were measured.

    Beispiel 4:Example 4:

    Es wurde eine Legierung mit 15,0 Gew.-% Nickel, 3,0 Gew.-% Aluminium, 1,2 Gew.-% Titan, 2,0 Gew.-% Molybdän und Rest Eisen wie in Beispiel 2 hergestellt. Nach einer Anlaßbehandlung bei 480°C wurde eine Koerzitivkraft Hc gleich 20 A/cm und eine Remanenz Br gleich 1,56 T gemessen. An alloy with 15.0% by weight of nickel, 3.0% by weight of aluminum, 1.2% by weight of titanium, 2.0% by weight of molybdenum and the rest of iron was produced as in Example 2. After an annealing treatment at 480 ° C, a coercive force H c equal to 20 A / cm and a remanence B r equal to 1.56 T were measured.

    Beispiel 5:Example 5:

    Es wurde eine Legierung mit 15,0 Gew.-% Nickel, 2,0 Gew.-% Aluminium, 0,8 Gew.-% Titan und Rest Eisen unter Vacuum erschmolzen. Der resultierende Gußbarren wurde bei ca. 1000°C warmgewalzt, bei 900°C für eine Stunde zwischengeglüht und in Wasser schnell abgekühlt. Nach einem anschließenden Kaltwalzen mit einer Querschnittsverringerung von 90 % wurde das resultierende Band bei 650°C für vier Stunden zwischengeglüht. Entsprechend einer Querschnittsverringerung von 95 % wurde das Band danach kaltgewalzt und für drei Stunden bei 460°C angelassen und luftgekühlt. Es wurde eine Koerzitivkraft Hc gleich 14 A/cm und eine Remanenz Br gleich 1,46 T gemessen.An alloy with 15.0% by weight of nickel, 2.0% by weight of aluminum, 0.8% by weight of titanium and the rest of iron was melted under vacuum. The resulting cast ingot was hot rolled at about 1000 ° C, annealed at 900 ° C for one hour and quickly cooled in water. After a subsequent cold rolling with a cross-section reduction of 90%, the resulting strip was annealed at 650 ° C for four hours. After a reduction in cross section of 95%, the strip was then cold rolled and tempered for three hours at 460 ° C. and air-cooled. A coercive force H c equal to 14 A / cm and a remanence B r equal to 1.46 T were measured.

    Beispiel 6:Example 6:

    Es wurde eine Legierung mit 15,0 Gew.-% Nickel, 2,5 Gew.-% Aluminium, 1,2 Gew.-% Titan und Rest Eisen wie im Beispiel 5 hergestellt, jedoch mit einer Querschnittsverringerung von 83 % und einer Anlaßbehandlung bei 420°C. Es wurde eine Koerzitivkraft Hc gleich 17 A/cm und eine Remanenz Br gleich 1,44 T gemessen.An alloy with 15.0% by weight of nickel, 2.5% by weight of aluminum, 1.2% by weight of titanium and the rest of iron was produced as in Example 5, but with a cross-sectional reduction of 83% and an annealing treatment at 420 ° C. A coercive force H c equal to 17 A / cm and a remanence B r equal to 1.44 T were measured.

    Bei allen Ausführungsbeispielen ergab sich ein befriedigendes Magnetisierungsverhalten und eine brauchbare Gegenfeldstabilität.A satisfactory result was found in all of the exemplary embodiments Magnetization behavior and a useful counter field stability.

    Claims (3)

    1. Display element for use in a magnetic anti-theft system consisting of:
      1. an elongated alarm strip consisting of an amorphous ferromagnetic alloy and at least
      2. one activation strip consisting of a medium-hard magnetic alloy,
      characterised in that
      a) the medium-hard magnetic alloy consists of
      8 to 25 % by weight Ni   0.5 to 3 % by weight Ti
      1.5 to 4.5 % by weight Al   with the remainder Fe
      and
      b) the alloy may furthermore contain
      0 to 5 % by weight Co and/or 0 to 3 % by weight Mo or Cr and/or
      at least one of the elements Zr, Hf, V, Nb, Ta, W, Mn and Si with an individual content of less than 0.5 % by weight of the alloys and a total content of less than 1 % by weight of the alloy and/or
      at least one of the elements C, N, S, P, B, H and 0 with an individual content of less than 0.2 % by weight of the alloy and a total content of less than 1 % by weight of the alloy, and
      c) the medium-hard magnetic alloy displays a coercive force Hc of 10 to 24 A/cm and remanence Br of at least 1.3 T (13 000 gauss).
    2. Display element according to claim 1, characterised in that the medium-hard magnetic alloy consists of
      13 to 17 % by weight Ni   0.5 to 1.5 % by weight Ti
      1.8 to 2.8 % by weight Al   with the remainder Fe.
    3. Process for the production of an activation strip according to claim 1 or claim 2, characterised by the following steps:
      1. melting the alloy in vacuo or in an inert-gas atmosphere and then casting it to form an ingot;
      2. hot working the ingot to form a strip at temperatures in excess of approximately 800°C;
      3. interannealing the strip at a temperature in excess of approximately 800°C;
      4. rapid cooling;
      5. cold working corresponding to a cross-sectional reduction of approximately 90%;
      6. interannealing at approximately 700°C;
      7. cold working corresponding to a cross-sectional reduction of at least 85 %;
      8. tempering at a temperature of approximately 480°C, and
      9. cutting the activation strips to length.
    EP98944989A 1997-07-30 1998-07-15 Display element for use in a magnetic anti-theft system Expired - Lifetime EP0929883B1 (en)

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    DE19732872A DE19732872C2 (en) 1997-07-30 1997-07-30 Display element for use in a magnetic anti-theft system
    DE19732872 1997-07-30
    PCT/DE1998/001984 WO1999006977A1 (en) 1997-07-30 1998-07-15 Display element for use in a magnetic anti-theft system

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    EP0929883B1 true EP0929883B1 (en) 2003-09-24

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    JP (1) JP3288725B2 (en)
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    EP0929883A1 (en) 1999-07-21
    WO1999006977A1 (en) 1999-02-11
    US20030129445A1 (en) 2003-07-10
    US6663981B1 (en) 2003-12-16
    DE19732872C2 (en) 2002-04-18
    JP2001502759A (en) 2001-02-27
    JP3288725B2 (en) 2002-06-04
    ES2209204T3 (en) 2004-06-16
    DE19732872A1 (en) 1999-02-04
    US6689490B2 (en) 2004-02-10

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