EP4039843A1 - Non ferromagnetic alloy, manufacturing proccess therefore and clock movement component made of that alloy - Google Patents

Non ferromagnetic alloy, manufacturing proccess therefore and clock movement component made of that alloy Download PDF

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Publication number
EP4039843A1
EP4039843A1 EP21155159.3A EP21155159A EP4039843A1 EP 4039843 A1 EP4039843 A1 EP 4039843A1 EP 21155159 A EP21155159 A EP 21155159A EP 4039843 A1 EP4039843 A1 EP 4039843A1
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EP
European Patent Office
Prior art keywords
alloy
weight
temperature
manganese
content
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EP21155159.3A
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German (de)
French (fr)
Inventor
Sandrine GUERIN DELETANG
Charlésia BRAGUIER
Christian David GEIßLER
Frédéric DIOLOGENT
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Richemont International SA
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Richemont International SA
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Priority to EP21155159.3A priority Critical patent/EP4039843A1/en
Priority to EP22703324.8A priority patent/EP4288577A1/en
Priority to PCT/EP2022/051955 priority patent/WO2022167327A1/en
Publication of EP4039843A1 publication Critical patent/EP4039843A1/en
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B17/00—Mechanisms for stabilising frequency
    • G04B17/04—Oscillators acting by spring tension
    • G04B17/06—Oscillators with hairsprings, e.g. balance
    • G04B17/066—Manufacture of the spiral spring
    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B43/00—Protecting clockworks by shields or other means against external influences, e.g. magnetic fields
    • G04B43/007—Antimagnetic alloys
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/001—Austenite
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium

Definitions

  • the present invention relates to an antiferromagnetic alloy based on iron, manganese, chromium and vanadium as well as its preparation process (alloying and transformation).
  • the invention also relates to mechanical parts composed at least in part of this antiferromagnetic alloy.
  • the field of use of the present invention relates to watchmaking, in particular resonators for timepieces.
  • a resonator for a timepiece has the primary function of resonating invariably regardless of the environment in which it is located. This is the reason why a resonator is preferably made of an Elinvar material (consisting for example of 59% iron, 36% nickel, and 5% chromium), that is to say that its modulus d 'Young (or elasticity) remains insensitive to temperature variations (Charles-Edouard Council, 1920 Nobel Prize in Physics).
  • the documents EP 1 422 436 and EP 0 886 195 propose solutions making it possible to have materials which are, in addition, insensitive to magnetic fields. Generally, a resonator is made from complex and expensive alloys.
  • the alloys of which the resonators for timepieces are made generally include, in addition to iron and nickel, several additives such as chromium, silicon, titanium, manganese and beryllium.
  • This alloy known as the Nivarox alloy, is an Elinvar alloy exhibiting a Young's modulus insensitive to temperature changes. In addition, its Young's modulus varies very slightly in the temperatures considered (-15 to -50°C in general) but much less than most alloys ( figure 1 ).
  • the document GB 1284066 describes an alloy comprising 0.5-1.5% vanadium and at least 1% molybdenum.
  • the document JP 0941087 describes an alloy comprising 0.03-0.10% carbon, 0.05-0.50% silicon and 0.5-7% molybdenum.
  • the document US 3,735,971 describes an alloy comprising 0.03-1% carbon or a mixture of carbon and nitrogen.
  • GB 2128633 describes an alloy comprising silicon and cobalt.
  • the antiferromagnetic alloy according to the invention mainly consists of iron, manganese, chromium and vanadium. With regard to its composition and its method of preparation, it provides an inexpensive alternative that can be easily implemented compared to the materials of the prior art.
  • This alloy has a hardness advantageously between 250 HV and 600 HV, for example between 300 HV and 550 HV, even more preferably between 400 HV and 550 HV, which is suitable for use in the field of watchmaking. Hardness values are measured with an accuracy of ⁇ 30 HV.
  • This alloy has a Young's modulus advantageously between 140 GPa and 240 GPa, preferentially between 150 GPa and 200 GPa, which is suitable for use in the field of watchmaking.
  • the Young's modulus of this alloy only varies very slightly (+/- 1 GPa) as a function of temperature, notably between 5°C and 40°C.
  • the invention also relates to a process for manufacturing this antiferromagnetic alloy and its use in the field of watchmaking, for example for manufacturing a resonator for a timepiece.
  • the antiferromagnetic alloy according to the invention is free of cobalt, beryllium and nickel.
  • the percentages are expressed by weight relative to the weight of the antiferromagnetic alloy. Value ranges include upper and lower bounds. For example, the value ranges " 15.0 to 35.0 %" and " between 15.0 and 35.0 %” include the values 15.0 and 35.0%.
  • This alloy consists of the above elements. In other words, it does not include other elements. Thus, this alloy is devoid of cobalt, beryllium, molybdenum and/or nickel.
  • the alloy is advantageously free of residual impurities.
  • it advantageously comprises a total of less than 6000 ppm of residual impurities (metallic and non-metallic), relative to its weight, more advantageously less than 3000 ppm, even more advantageously less than 1500 ppm, and even more advantageously less than 600 ppm.
  • Any residual metallic impurities may include in particular the elements Co, Be, Mo, Zn or Ni.
  • the ppm are expressed by weight relative to the weight of the antiferromagnetic alloy (Fe+Mn+Cr+V+C+Si+Al).
  • Residual non-metallic impurities may correspond to at least one of the following elements: selenium, sulphur, oxygen and nitrogen.
  • the oxygen or sulfur concentration is less than 500 ppm, advantageously less than 300 ppm, even more advantageously less than 100 ppm.
  • the nitrogen concentration is advantageously less than 100 ppm, advantageously less than 20 ppm.
  • the manganese content is between 15.0% and 35.0% by weight, preferably between 20.0% and 35.0% by weight, more preferably between 22.0 and 32.0% by weight.
  • Such manganese contents are important because iron alloys with such manganese contents become austenitic and antiferromagnetic. So enough is needed for the iron to no longer be ferromagnetic. On the other hand, it is useless to exceed the optimum manganese concentration.
  • the chromium content is between 4.0% and 15.0% by weight, preferably between 5.0% and 12.0% by weight, more preferably between 6.0 and 10.0% by weight. Chromium forms a protective oxide layer in contact with air (also called passivation layer) which improves the corrosion resistance of the material.
  • the vanadium content is between 1.0% and 5.0% by weight, advantageously between 1.6% and 3.5% by weight.
  • Vanadium allows the formation of stable and hard carbides, while guaranteeing, by synergy effect with chromium, a significant increase in hardness.
  • the addition of vanadium improves the mechanical characteristics of the alloy, thanks to a refining of the grain of the alloy induced by the precipitates of vanadium carbides.
  • the formation of stable and hard carbides within the alloy allows the shape to be fixed, in particular when the alloy is used to shape a watch movement, for example a resonator in the form of a spiral spring.
  • the carbon content is between 0.1% and 2.0% by weight, preferably between 0.1% and 1.0%, more preferably between 0.3% and 1.0% by weight.
  • the silicon content is between 0.1% and 1.0% by weight, advantageously between 0.1% and 0.5% by weight.
  • the alloy may comprise aluminum.
  • the aluminum content is between 0% and 2.0% by weight, advantageously between 0.5% and 2.0% by weight, and even more advantageously between 0.5% and 1.5% by weight.
  • the characteristics of invariable elasticity (Elinvar) and very low thermal expansion (Invar) are obtained simultaneously in a wide range of lower temperatures.
  • the Néel temperature (T N ) being defined as the magnetic phase transition temperature above which a material antiferromagnetic becomes paramagnetic. In other words, at temperature T N , the thermal energy is sufficient to break the microscopic magnetic order.
  • the amount of iron is adjusted according to the embodiments and corresponds to the amount necessary to reach 100% by weight. It is between 40.0 and 79.8%. As already indicated, the quantity of residual impurities is advantageously less than 6000 ppm.
  • the antiferromagnetic alloy according to the invention is used in the field of watchmaking, in particular for the manufacture of a watch movement component.
  • the present invention also relates to a watch movement component at least partly made of this antiferromagnetic alloy. It is advantageously made entirely of this alloy.
  • the watch movement component is a resonator, at least partly made of this antiferromagnetic alloy.
  • the resonator consists entirely of the antiferromagnetic alloy.
  • the resonator is in the form of a spiral spring, but it can also be a resonator with flexible blades, such as a tuning fork, or even a resonator of the virtual pivot type, using to the principle of flexible guidance.
  • the invention also relates to a watch movement comprising at least one component consisting at least in part of this antiferromagnetic alloy.
  • the invention also relates to a watch comprising a watch movement of which at least one of the components comprises this antiferromagnetic alloy.
  • This watch comprises at least one component at least partly consisting of the antiferromagnetic alloy.
  • the component is a resonator and more preferably, the component is a spiral spring entirely made of the alloy according to the invention.
  • the process for manufacturing the antiferromagnetic alloy according to the invention comprises at least one melting and one purification step.
  • the cast iron makes it possible to form the alloy with the desired metals.
  • the second casting purifies the alloy by removing as many impurities as possible.
  • Particular attention is paid to manganese whose partial pressure of its gas is relatively high at the melting temperatures of the alloy.
  • the method according to the invention makes it possible to retain the same quantity of manganese before and after melting and a purification step.
  • the alloy has a total content of impurities less than or equal to 6000 ppm, advantageously less than 3000 ppm, more advantageously less than 1500 ppm, and even more advantageously less than 600 ppm.
  • the impurities are those mentioned above.
  • the purification step at pressure P is carried out in such a way as to limit the evaporation of manganese.
  • the variation in the manganese content resulting from the purification step carried out at pure temperature T and under pressure P does not exceed 5.0%.
  • the purification step results in a manganese variation advantageously less than or equal to 5.0% by weight, relative to the amount of manganese resulting from the melting step.
  • the pure temperature T is between 1250 and 1700°C, advantageously between 1350 and 1500°C.
  • the temperature of the step of melting the constituents of the alloy is between 1250°C and 1700°C, advantageously between 1350°C and 1500°C.
  • manganese tends to evaporate quite quickly above a certain temperature.
  • the manganese content of the final alloy being very important for obtaining certain properties of the material, it is important to resort to a process limiting its evaporation. While evaporation depends, above a certain temperature, on the pressure of exposure of the material to the process, a step carried out under pressure substantially reduces the variation in manganese concentration.
  • the purification step carried out at a temperature T according to the range stated above is carried out at a pressure P greater than 10 bar, advantageously greater than 20 bar, and even more advantageously greater than 40 bar.
  • the pressure P is less than or equal to 50 bar.
  • the melting step is not necessarily carried out at a pressure greater than atmospheric pressure. It can in particular be carried out under vacuum, for example in a vacuum induction furnace.
  • this alloy In order to use this alloy in the field of watchmaking, it is shaped using conventional techniques.
  • an ingot of the antiferromagnetic alloy is hot forged.
  • the forging of the ingot is carried out at a temperature below the melting temperature of the alloy, preferably less than or equal to 1100°C.
  • the forging temperature is advantageously above 800°C.
  • Forging makes it possible to obtain bars whose diameter is preferably between 10 mm and 40 mm, more preferably between 15 mm and 25 mm.
  • the bars obtained by hot forging are then hot and then cold rolled to a diameter of 5 mm.
  • the rolling is carried out after a heat treatment at a temperature preferably between 800° C. and 1200° C., more preferably between 900° C. and 1100° C. to lower its hardness.
  • the bars with a diameter of 5 mm are then cold drawn to the desired diameter, advantageously of the order of 0.5 mm.
  • one or more heat treatments can be implemented. These heat treatments are carried out at a temperature advantageously between 800°C and 1200°C, more advantageously between 900°C and 1100°C.
  • the alloy can then be drawn to a final diameter advantageously less than 100 ⁇ m then rolled, rolled up and fixed to form a spiral spring.
  • Table 2 conditions for preparing the alloys according to the invention INV-1 and INV-2. Terms INV-1 ( figure 2 ) INV-2 ( figure 3 ) Time 90 mins 90 mins Fixing temperature 610°C 600°C
  • the two alloys INV-1 and INV-2 have a Vickers hardness of 520 HV and 460 HV respectively +/- 30 HV.

Abstract

La présente invention concerne un alliage antiferromagnétique constitué de :• 15,0 % à 35,0 % en poids de manganèse,• 4,0 % à 15,0 % en poids de chrome,• 1,0 % à 5,0 % en poids de vanadium,• 0,1 % à 2,0 % en poids de carbone,• 0,1 % à 1,0 % en poids de silicium,• 0 % à 2,0 % en poids d'aluminium,• le reste étant du fer et des impuretés résiduelles.Cet alliage peut être utilisé dans le domaine de l'horlogerie, notamment pour la fabrication d'un composant de mouvement horloger.The present invention relates to an antiferromagnetic alloy consisting of:• 15.0% to 35.0% by weight manganese,• 4.0% to 15.0% by weight chromium,• 1.0% to 5.0% by weight vanadium,• 0.1% to 2.0% by weight carbon,• 0.1% to 1.0% by weight silicon,• 0% to 2.0% by weight aluminum,• the remainder being iron and residual impurities. This alloy can be used in the field of watchmaking, in particular for the manufacture of a watch movement component.

Description

DOMAINE DE L'INVENTIONFIELD OF THE INVENTION

La présente invention concerne un alliage antiferromagnétique à base de fer, de manganèse, de chrome et de vanadium ainsi que son procédé de préparation (mise en alliage et transformation). L'invention concerne également des pièces mécaniques composées au moins en partie de cet alliage antiferromagnétique.The present invention relates to an antiferromagnetic alloy based on iron, manganese, chromium and vanadium as well as its preparation process (alloying and transformation). The invention also relates to mechanical parts composed at least in part of this antiferromagnetic alloy.

Le domaine d'utilisation de la présente invention concerne l'horlogerie, en particulier les résonateurs pour pièce d'horlogerie.The field of use of the present invention relates to watchmaking, in particular resonators for timepieces.

ETAT ANTERIEUR DE LA TECHNIQUEPRIOR STATE OF THE TECHNIQUE

Un résonateur pour pièce d'horlogerie a pour fonction première de résonner de manière invariable quel que soit l'environnement dans lequel il se trouve. C'est la raison pour laquelle un résonateur est préférentiellement constitué d'un matériau Élinvar (constitué par exemple de 59 % de fer, 36 % de nickel, et 5 % de chrome), c'est-à-dire que son module d'Young (ou d'élasticité) reste insensible aux variations de températures (Charles-Edouard Guillaume, prix Nobel de physique de 1920). Les documents EP 1 422 436 et EP 0 886 195 proposent des solutions permettant d'avoir des matériaux qui sont, en plus, insensibles aux champs magnétiques. De manière générale, un résonateur est fabriqué à partir d'alliages complexes et coûteux.A resonator for a timepiece has the primary function of resonating invariably regardless of the environment in which it is located. This is the reason why a resonator is preferably made of an Elinvar material (consisting for example of 59% iron, 36% nickel, and 5% chromium), that is to say that its modulus d 'Young (or elasticity) remains insensitive to temperature variations (Charles-Edouard Guillaume, 1920 Nobel Prize in Physics). The documents EP 1 422 436 and EP 0 886 195 propose solutions making it possible to have materials which are, in addition, insensitive to magnetic fields. Generally, a resonator is made from complex and expensive alloys.

Historiquement, l'alliage le plus utilisé est une base fer-nickel. Plusieurs additifs ont été incorporés à cet alliage de base pour conférer les propriétés requises de résistance mécanique, de résistance à la corrosion, ou encore de résistance aux variations de température ou de pression. Ainsi, les alliages dont les résonateurs pour pièce d'horlogerie sont constitués comprennent généralement, en plus du fer et du nickel, plusieurs additifs tels que le chrome, le silicium, le titane, le manganèse et le béryllium. Cet alliage, connu comme l'alliage Nivarox, est un alliage Élinvar présentant un module d'Young insensible aux changements de température. En outre, son module d'Young varie très légèrement dans les températures considérées (-15 à -50 °C en général) mais beaucoup moins que la plupart des alliages (figure 1).Historically, the most widely used alloy is an iron-nickel base. Several additives have been incorporated into this base alloy to provide the required properties of mechanical strength, corrosion resistance, or even resistance to temperature or pressure variations. Thus, the alloys of which the resonators for timepieces are made generally include, in addition to iron and nickel, several additives such as chromium, silicon, titanium, manganese and beryllium. This alloy, known as the Nivarox alloy, is an Elinvar alloy exhibiting a Young's modulus insensitive to temperature changes. In addition, its Young's modulus varies very slightly in the temperatures considered (-15 to -50°C in general) but much less than most alloys ( figure 1 ).

Cependant, les procédés de fabrication de ces alliages sont complexes et la reproductibilité de ceux-ci est limitée, ce qui peut entrainer des modifications des propriétés mécaniques intrinsèques des alliages. Le principal problème de cet alliage est qu'il est sensible aux champs magnétiques. Or, ces dernières années, l'environnement magnétique des montres à bien changé avec les nouvelles technologies telles que les téléphones portables, les bracelets connectés et les ordinateurs portables ou l'augmentation de la puissance et du nombre d'aimants dans la vie quotidienne (fermoir de sac à mains, fermeture de portes ou encore détecteurs de métaux).However, the manufacturing processes of these alloys are complex and their reproducibility is limited, which can lead to modifications of the intrinsic mechanical properties of the alloys. The main problem with this alloy is that it is sensitive to magnetic fields. However, in recent years, the magnetic environment of watches has changed considerably with new technologies such as mobile phones, connected bracelets and laptop computers or the increase in the power and number of magnets in daily life ( handbag clasps, door closures or even metal detectors).

Par ailleurs, l'évolution des réglementations sur les produits chimiques étant constante, la plupart des alliages connus ne peuvent ou ne pourront plus nécessairement être produits dans le futur. En effet, bon nombre d'entre eux contiennent des éléments potentiellement dangereux pour la santé comme des allergènes, des cancérigènes, des mutagènes ou des reprotoxiques. Ainsi, il serait très avantageux de développer un nouvel alliage ayant toutes les propriétés mécaniques, magnétiques, de résistance à la corrosion, Élinvar (module d'Young insensible aux changements de température) et étant inoffensifs pour la santé pour servir de matériau de base d'un résonateur pour pièce d'horlogerie.Moreover, the evolution of the regulations on the chemical products being constant, the majority of the known alloys cannot or will not necessarily be able to be produced in the future. Indeed, many of them contain elements potentially dangerous to health such as allergens, carcinogens, mutagens or reprotoxins. Thus, it would be very advantageous to develop a new alloy having all the mechanical, magnetic, corrosion resistance properties, Elinvar (Young's modulus insensitive to temperature changes) and being harmless to health to serve as a base material for a resonator for a timepiece.

Une alternative aux alliages métalliques a été développée. Cette alternative consiste à graver des galettes de silicium ce qui rend entre-autres le procédé de fabrication reproductible. Cependant, notamment dans le cas d'une utilisation en tant que ressort spiral, le comportement mécanique n'est pas homogène en fonction de l'axe du mouvement ( EP 1 422 436 ). D'autre part, les procédés de fabrication actuels limitent les géométries du résonateur ainsi que les opérations de correction par déformation plastique par exemple, comme la réalisation d'une courbe terminale Phillips ou Breguet.An alternative to metal alloys has been developed. This alternative consists of etching silicon wafers which, among other things, makes the manufacturing process reproducible. However, especially in the case of use as a spiral spring, the mechanical behavior is not homogeneous depending on the axis of the movement ( EP 1 422 436 ). On the other hand, the current manufacturing methods limit the geometries of the resonator as well as the operations of correction by plastic deformation for example, such as the production of a terminal Phillips or Breguet curve.

Le document GB 1284066 décrit un alliage comprenant 0,5-1,5 % de vanadium et au moins 1 % de molybdène. Le document JP 0941087 décrit un alliage comprenant 0,03-0,10 % de carbone, 0,05-0,50 % de silicium et 0,5-7 % de molybdène. Le document US 3,735,971 décrit un alliage comprenant 0,03-1 % de carbone ou d'un mélange de carbone et d'azote. GB 2128633 décrit un alliage comprenant du silicium et du cobalt.The document GB 1284066 describes an alloy comprising 0.5-1.5% vanadium and at least 1% molybdenum. The document JP 0941087 describes an alloy comprising 0.03-0.10% carbon, 0.05-0.50% silicon and 0.5-7% molybdenum. The document US 3,735,971 describes an alloy comprising 0.03-1% carbon or a mixture of carbon and nitrogen. GB 2128633 describes an alloy comprising silicon and cobalt.

Une autre alternative a été développée pour un alliage antiferromagnétique à base de fer, de manganèse, de chrome et de nickel. Cet alliage est décrit dans WO 2018/083311 . Cet alliage peut servir de matériau pour la fabrication d'un résonateur pour pièce d'horlogerie. En effet, cet alliage présente les propriétés mécaniques requises pour pouvoir être mis en forme pour former un ressort spiral par exemple, ce qui n'est pas le cas de tous les alliages antiferromagnétiques. Pour cela, l'alliage doit pouvoir être tréfilé, laminé, enroulé et présenter des propriétés élastiques adéquates.Another alternative has been developed for an antiferromagnetic alloy based on iron, manganese, chromium and nickel. This alloy is described in WO 2018/083311 . This alloy can be used as a material for the manufacture of a resonator for a timepiece. Indeed, this alloy has the mechanical properties required to be able to be shaped to form a spiral spring for example, which is not the case for all antiferromagnetic alloys. For this, the alloy must be able to be drawn, rolled, wound and have adequate elastic properties.

Il existe cependant un besoin pour des alternatives à ce dernier alliage, en particulier pour des alliages dépourvus de nickel.However, there is a need for alternatives to this latter alloy, in particular for alloys free of nickel.

EXPOSÉ DE L'INVENTIONDISCLOSURE OF THE INVENTION

L'alliage antiferromagnétique selon l'invention est principalement constitué de fer, de manganèse, de chrome et de vanadium. Eu égard à sa composition et à son procédé de préparation, il procure une alternative peu onéreuse et pouvant être aisément mise en œuvre par rapport aux matériaux de l'art antérieur.The antiferromagnetic alloy according to the invention mainly consists of iron, manganese, chromium and vanadium. With regard to its composition and its method of preparation, it provides an inexpensive alternative that can be easily implemented compared to the materials of the prior art.

Cet alliage présente une dureté avantageusement comprise entre 250 HV et 600 HV, par exemple entre 300 HV et 550 HV, encore plus préférentiellement entre 400 HV et 550 HV, ce qui est adapté pour une utilisation dans le domaine de l'horlogerie. Les valeurs de dureté sont mesurées avec une précision de ± 30 HV.This alloy has a hardness advantageously between 250 HV and 600 HV, for example between 300 HV and 550 HV, even more preferably between 400 HV and 550 HV, which is suitable for use in the field of watchmaking. Hardness values are measured with an accuracy of ± 30 HV.

Cet alliage présente un module d'Young avantageusement compris entre 140 GPa et 240 GPa, préférentiellement entre 150 GPa et 200 GPa, ce qui est adapté pour une utilisation dans le domaine de l'horlogerie. Le module d'Young de cet alliage ne varie que très faiblement (+/- 1 GPa) en fonction de la température, notamment entre 5 °C et 40 °C.This alloy has a Young's modulus advantageously between 140 GPa and 240 GPa, preferentially between 150 GPa and 200 GPa, which is suitable for use in the field of watchmaking. The Young's modulus of this alloy only varies very slightly (+/- 1 GPa) as a function of temperature, notably between 5°C and 40°C.

Ainsi, l'invention concerne également un procédé de fabrication de cet alliage antiferromagnétique et son utilisation dans le domaine de l'horlogerie, par exemple pour fabriquer un résonateur pour pièce d'horlogerie.Thus, the invention also relates to a process for manufacturing this antiferromagnetic alloy and its use in the field of watchmaking, for example for manufacturing a resonator for a timepiece.

AlliageAlloy

Selon un premier mode de réalisation de l'invention, l'alliage antiferromagnétique ayant une composition constituée de :

  • 15,0 % à 35,0 % en poids de manganèse,
  • 4,0 % à 15,0 % en poids de chrome,
  • 1,0 % à 5,0 % en poids de vanadium,
  • 0,1 % à 2,0 % en poids de carbone,
  • 0,1 % à 1,0 % en poids de silicium,
  • 0 % à 2,0 % en poids d'aluminium,
  • le reste étant du fer et des impuretés résiduelles.
According to a first embodiment of the invention, the antiferromagnetic alloy having a composition consisting of:
  • 15.0% to 35.0% by weight manganese,
  • 4.0% to 15.0% by weight of chromium,
  • 1.0% to 5.0% by weight vanadium,
  • 0.1% to 2.0% by weight carbon,
  • 0.1% to 1.0% by weight silicon,
  • 0% to 2.0% by weight aluminum,
  • the remainder being iron and residual impurities.

Ainsi, l'alliage antiferromagnétique selon l'invention est exempt de cobalt, de béryllium et de nickel.Thus, the antiferromagnetic alloy according to the invention is free of cobalt, beryllium and nickel.

Les pourcentages sont exprimés en poids par rapport au poids de l'alliage antiferromagnétique. Les plages de valeurs incluent les bornes supérieures et inférieures. Par exemple, les plages de valeurs « 15,0 à 35,0 % » et « entre 15,0 et 35,0 % » incluent les valeurs 15,0 et 35,0 %.The percentages are expressed by weight relative to the weight of the antiferromagnetic alloy. Value ranges include upper and lower bounds. For example, the value ranges " 15.0 to 35.0 %" and " between 15.0 and 35.0 %" include the values 15.0 and 35.0%.

Cet alliage est constitué des éléments ci-dessus. En d'autres termes, il ne comprend pas d'autres éléments. Ainsi, cet alliage est dépourvu de cobalt, de béryllium, de molybdène et/ou de nickel.This alloy consists of the above elements. In other words, it does not include other elements. Thus, this alloy is devoid of cobalt, beryllium, molybdenum and/or nickel.

L'alliage est avantageusement dépourvu d'impuretés résiduelles. Ainsi, il comprend avantageusement un total de moins de 6000 ppm d'impuretés résiduelles (métalliques et non métalliques), par rapport à son poids, plus avantageusement moins de 3000 ppm, encore plus avantageusement moins de 1500 ppm, et encore plus avantageusement moins de 600 ppm.The alloy is advantageously free of residual impurities. Thus, it advantageously comprises a total of less than 6000 ppm of residual impurities (metallic and non-metallic), relative to its weight, more advantageously less than 3000 ppm, even more advantageously less than 1500 ppm, and even more advantageously less than 600 ppm.

Les éventuelles impuretés résiduelles métalliques peuvent inclure notamment les éléments Co, Be, Mo, Zn ou Ni.Any residual metallic impurities may include in particular the elements Co, Be, Mo, Zn or Ni.

Les ppm sont exprimées en poids par rapport au poids de l'alliage antiferromagnétique (Fe+Mn+Cr+V+C+Si+Al).The ppm are expressed by weight relative to the weight of the antiferromagnetic alloy (Fe+Mn+Cr+V+C+Si+Al).

Les bénéfices liés à la présence des éléments de l'alliage sont supérieurs à tout effet négatif qui pourrait résulter de la présence d'impuretés résiduelles, même lorsque la quantité d'impuretés dépasse celle de ces éléments (carbone, silicium ou aluminium).The benefits linked to the presence of the elements of the alloy are superior to any negative effect which could result from the presence of residual impurities, even when the quantity of impurities exceeds that of these elements (carbon, silicon or aluminium).

Les impuretés résiduelles non métalliques peuvent correspondre à au moins un des éléments suivants : sélénium, soufre, oxygène et azote. De préférence, dans cet alliage, la concentration en oxygène ou en soufre est inférieure à 500 ppm, avantageusement inférieure à 300 ppm, encore plus avantageusement inférieure à 100 ppm. Finalement, la concentration en azote est avantageusement inférieure à 100 ppm, avantageusement inférieure à 20 ppm.Residual non-metallic impurities may correspond to at least one of the following elements: selenium, sulphur, oxygen and nitrogen. Preferably, in this alloy, the oxygen or sulfur concentration is less than 500 ppm, advantageously less than 300 ppm, even more advantageously less than 100 ppm. Finally, the nitrogen concentration is advantageously less than 100 ppm, advantageously less than 20 ppm.

La teneur en manganèse est comprise entre 15,0 % et 35,0 % en poids, avantageusement entre 20,0 % et 35,0 % en poids, plus avantageusement entre 22,0 et 32,0 % en poids. De telles teneurs en manganèse sont importantes, car les alliages de fer présentant ces teneurs en manganèse deviennent austénitiques et antiferromagnétiques. Il en faut donc suffisamment pour que le fer ne soit plus ferromagnétique. En revanche, il est inutile de dépasser la concentration optimum en manganèse.The manganese content is between 15.0% and 35.0% by weight, preferably between 20.0% and 35.0% by weight, more preferably between 22.0 and 32.0% by weight. Such manganese contents are important because iron alloys with such manganese contents become austenitic and antiferromagnetic. So enough is needed for the iron to no longer be ferromagnetic. On the other hand, it is useless to exceed the optimum manganese concentration.

La teneur en chrome est comprise entre 4,0 % et 15,0 % en poids, avantageusement entre 5,0 % et 12,0 % en poids, plus avantageusement entre 6,0 et 10,0 % en poids. Le chrome forme une couche d'oxyde protectrice au contact de l'air (aussi appelée couche de passivation) qui améliore la résistance à la corrosion du matériau.The chromium content is between 4.0% and 15.0% by weight, preferably between 5.0% and 12.0% by weight, more preferably between 6.0 and 10.0% by weight. Chromium forms a protective oxide layer in contact with air (also called passivation layer) which improves the corrosion resistance of the material.

La teneur en vanadium est comprise entre 1,0 % et 5,0 % en poids, avantageusement entre 1,6 % et 3,5 % en poids. Le vanadium permet la formation de carbures stables et durs, tout en garantissant, par effet de synergie avec le chrome, une augmentation significative de la dureté. L'ajout de vanadium améliore les caractéristiques mécaniques de l'alliage, grâce à un affinage du grain de l'alliage induit par les précipités de carbures de vanadium. En outre, la formation de carbures stables et durs au sein de l'alliage permet le fixage de la forme, notamment lorsque l'alliage est utilisé pour façonner un mouvement horloger, par exemple un résonateur sous forme de ressort spiral.The vanadium content is between 1.0% and 5.0% by weight, advantageously between 1.6% and 3.5% by weight. Vanadium allows the formation of stable and hard carbides, while guaranteeing, by synergy effect with chromium, a significant increase in hardness. The addition of vanadium improves the mechanical characteristics of the alloy, thanks to a refining of the grain of the alloy induced by the precipitates of vanadium carbides. In addition, the formation of stable and hard carbides within the alloy allows the shape to be fixed, in particular when the alloy is used to shape a watch movement, for example a resonator in the form of a spiral spring.

La teneur en carbone est comprise entre 0,1 % et 2,0 % en poids, avantageusement entre 0,1 % et 1,0 %, plus avantageusement entre 0,3 % et 1,0 % en poids.The carbon content is between 0.1% and 2.0% by weight, preferably between 0.1% and 1.0%, more preferably between 0.3% and 1.0% by weight.

La teneur en silicium est comprise entre 0,1 % et 1,0 % en poids, avantageusement entre 0,1 % et 0,5 % en poids.The silicon content is between 0.1% and 1.0% by weight, advantageously between 0.1% and 0.5% by weight.

Selon un autre mode de réalisation, l'alliage peut comprendre de l'aluminium. La teneur en aluminium est comprise entre 0 % et 2,0 % en poids, avantageusement entre 0,5 % et 2,0 % en poids, et encore plus avantageusement entre 0,5 % et 1,5 % en poids.According to another embodiment, the alloy may comprise aluminum. The aluminum content is between 0% and 2.0% by weight, advantageously between 0.5% and 2.0% by weight, and even more advantageously between 0.5% and 1.5% by weight.

Lorsque de l'aluminium est utilisé comme élément d'addition à l'alliage fer-manganèse de base, les caractéristiques d'élasticité invariable (Élinvar) et de très faible dilatation thermique (Invar) sont obtenues simultanément dans une large gamme de températures inférieures à la température de Néel. La température de Néel (TN) étant définie comme la température de transition de phase magnétique au-dessus de laquelle un matériau antiferromagnétique devient paramagnétique. En d'autres termes, à la température TN, l'énergie thermique est suffisante pour rompre l'ordre magnétique microscopique.When aluminum is used as an addition element to the basic iron-manganese alloy, the characteristics of invariable elasticity (Elinvar) and very low thermal expansion (Invar) are obtained simultaneously in a wide range of lower temperatures. at Néel temperature. The Néel temperature (T N ) being defined as the magnetic phase transition temperature above which a material antiferromagnetic becomes paramagnetic. In other words, at temperature T N , the thermal energy is sufficient to break the microscopic magnetic order.

Selon un mode de réalisation particulier, l'alliage antiferromagnétique est constitué de :

  • 20,0 % à 35,0 % en poids de manganèse, avantageusement 22,0 % à 32,0 %,
  • 5,0 % à 12,0 % en poids de chrome, avantageusement 6,0 % à 10,0 %,
  • 1,6 % à 3,5 % en poids de vanadium,
  • 0,1 % à 1,0 % en poids de carbone, avantageusement 0,3 % à 1,0 %,
  • 0,1 % à 0,5 % en poids de silicium,
  • 0 % à 2,0 % en poids d'aluminium, avantageusement 0,5 % à 2,0 %, plus avantageusement 0,5 % à 1,5 %,
  • le reste étant du fer et des impuretés résiduelles.
According to a particular embodiment, the antiferromagnetic alloy consists of:
  • 20.0% to 35.0% by weight of manganese, advantageously 22.0% to 32.0%,
  • 5.0% to 12.0% by weight of chromium, advantageously 6.0% to 10.0%,
  • 1.6% to 3.5% by weight of vanadium,
  • 0.1% to 1.0% by weight of carbon, advantageously 0.3% to 1.0%,
  • 0.1% to 0.5% by weight of silicon,
  • 0% to 2.0% by weight aluminum, preferably 0.5% to 2.0%, more preferably 0.5% to 1.5%,
  • the remainder being iron and residual impurities.

La quantité de fer est ajustée en fonction des modes de réalisation et correspond à la quantité nécessaire pour atteindre 100 % en poids. Elle est comprise entre 40,0 et 79,8 %. Comme déjà indiqué, la quantité d'impuretés résiduelles est avantageusement inférieure à 6000 ppm.The amount of iron is adjusted according to the embodiments and corresponds to the amount necessary to reach 100% by weight. It is between 40.0 and 79.8%. As already indicated, the quantity of residual impurities is advantageously less than 6000 ppm.

Utilisation de l'alliageUse of the alloy

De manière avantageuse, l'alliage antiferromagnétique selon l'invention est utilisé dans le domaine de l'horlogerie, notamment pour la fabrication d'un composant de mouvement horloger.Advantageously, the antiferromagnetic alloy according to the invention is used in the field of watchmaking, in particular for the manufacture of a watch movement component.

Aussi, la présente invention concerne également un composant de mouvement horloger au moins en partie constitué de cet alliage antiferromagnétique. Il est avantageusement intégralement constitué de cet alliage.Also, the present invention also relates to a watch movement component at least partly made of this antiferromagnetic alloy. It is advantageously made entirely of this alloy.

Selon un autre mode de réalisation particulier, le composant de mouvement horloger est un résonateur, au moins en partie constitué de cet alliage antiferromagnétique. De manière avantageuse, le résonateur est entièrement constitué de l'alliage antiferromagnétique.According to another particular embodiment, the watch movement component is a resonator, at least partly made of this antiferromagnetic alloy. Advantageously, the resonator consists entirely of the antiferromagnetic alloy.

Selon un autre mode de réalisation particulier, le résonateur est sous forme de ressort spiral, mais il peut aussi s'agir d'un résonateur à lames flexibles, comme un diapason, ou encore d'un résonateur de type à pivot virtuel, faisant appel au principe de guidage flexible.According to another particular embodiment, the resonator is in the form of a spiral spring, but it can also be a resonator with flexible blades, such as a tuning fork, or even a resonator of the virtual pivot type, using to the principle of flexible guidance.

L'invention concerne également un mouvement horloger comprenant au moins un composant constitué au moins en partie de cet alliage antiferromagnétique.The invention also relates to a watch movement comprising at least one component consisting at least in part of this antiferromagnetic alloy.

L'invention concerne également une montre comprenant un mouvement horloger dont au moins un des composants comprend cet alliage antiferromagnétique.The invention also relates to a watch comprising a watch movement of which at least one of the components comprises this antiferromagnetic alloy.

Cette montre comprend au moins un composant au moins en partie constitué de l'alliage antiferromagnétique. De manière préférée, le composant est un résonateur et de manière plus préférée, le composant est un ressort spiral intégralement constitué de l'alliage selon l'invention.This watch comprises at least one component at least partly consisting of the antiferromagnetic alloy. Preferably, the component is a resonator and more preferably, the component is a spiral spring entirely made of the alloy according to the invention.

Procédé de fabrication et façonnage de l'alliage antiferromagnétiqueManufacturing process and shaping of the antiferromagnetic alloy

Le procédé de fabrication de l'alliage antiferromagnétique selon l'invention comporte au moins une fonte et une étape de purification. La fonte permet de former l'alliage avec les métaux désirés. La deuxième fonte permet de purifier l'alliage par le retrait d'un maximum d'impuretés. Une attention particulière est portée sur le manganèse dont la pression partielle de son gaz est relativement élevée aux températures de fusion de l'alliage. De manière avantageuse, le procédé selon l'invention permet de conserver la même quantité de manganèse avant et après une fonte et une étape de purification.The process for manufacturing the antiferromagnetic alloy according to the invention comprises at least one melting and one purification step. The cast iron makes it possible to form the alloy with the desired metals. The second casting purifies the alloy by removing as many impurities as possible. Particular attention is paid to manganese whose partial pressure of its gas is relatively high at the melting temperatures of the alloy. Advantageously, the method according to the invention makes it possible to retain the same quantity of manganese before and after melting and a purification step.

Ce procédé pour réaliser un alliage comprenant du fer et du manganèse, et plus particulièrement d'un alliage selon l'invention. Ce procédé comporte notamment les étapes successives suivantes :

  • une étape de fonte des constituants de l'alliage, réalisée en une ou plusieurs phases, permettant de former l'alliage contenant les métaux désirés, et opérée à une température Tfon égale ou supérieure à la température de fonte des constituants de l'alliage,
    les constituants de l'alliage étant au moins à base de fer et à base de manganèse,
  • une étape de purification, réalisée en une ou plusieurs phases, permettant d'enlever les impuretés des constituants de l'alliage tout en limitant l'évaporation de manganèse, et opérée à une température Tpur et à une pression P supérieure à la pression atmosphérique.
This process for producing an alloy comprising iron and manganese, and more particularly an alloy according to the invention. This method comprises in particular the following successive steps:
  • a step of melting the constituents of the alloy, carried out in one or more phases, making it possible to form the alloy containing the desired metals, and operated at a temperature T fon equal to or greater than the melting temperature of the constituents of the alloy ,
    the constituents of the alloy being at least iron-based and manganese-based,
  • a purification step, carried out in one or more phases, allowing the impurities of the constituents of the alloy to be removed while limiting the evaporation of manganese, and carried out at a pure temperature T and at a pressure P greater than atmospheric pressure .

De manière avantageuse, à l'issue de l'étape de purification, l'alliage présente une teneur totale en impuretés inférieure ou égale à 6000 ppm, avantageusement inférieure à 3000 ppm, plus avantageusement inférieure à 1500 ppm, et encore plus avantageusement inférieure à 600 ppm. Les impuretés sont celles mentionnées ci-dessus.Advantageously, at the end of the purification step, the alloy has a total content of impurities less than or equal to 6000 ppm, advantageously less than 3000 ppm, more advantageously less than 1500 ppm, and even more advantageously less than 600 ppm. The impurities are those mentioned above.

L'étape de purification à la pression P est réalisée de manière à limiter l'évaporation du manganèse. Ainsi, de manière avantageuse, la variation de la teneur en manganèse résultant de l'étape de purification opérée à la température Tpur et sous pression P ne dépasse pas 5,0 %. En d'autres termes, il résulte de l'étape de purification une variation en manganèse avantageusement inférieure ou égale à 5,0 % en poids, par rapport à la quantité de manganèse résultant de l'étape de fonte.The purification step at pressure P is carried out in such a way as to limit the evaporation of manganese. Thus, advantageously, the variation in the manganese content resulting from the purification step carried out at pure temperature T and under pressure P does not exceed 5.0%. In other words, the purification step results in a manganese variation advantageously less than or equal to 5.0% by weight, relative to the amount of manganese resulting from the melting step.

Ainsi, le procédé de fabrication de l'alliage antiferromagnétique selon l'invention comporte au moins les étapes successives suivantes :

  1. a) une étape de fonte des constituants de l'alliage permettant de former l'alliage avec les métaux désirés ; cette étape peut par exemple être réalisée dans un four à arc (notamment un four à arc électrique) ou un four à induction sous vide (VIM : vacuum induction melting),
  2. b) une fonte de l'alliage obtenu à l'étape a) permettant de purifier l'alliage tout en limitant la variation de la teneur en manganèse, notamment en limitant son évaporation en réalisant cette étape à une pression supérieure à la pression atmosphérique. Sans se limiter à cette technique, cette étape peut par exemple être réalisée par une technique de refusion sous laitier électro-conducteur sous pression (PESR : pressure electro slag remelting) pour permettre la dissolution des impuretés et des inclusions. L'étape de purification est ainsi réalisée par un procédé impliquant une refusion à une pression supérieure à la pression atmosphérique, avantageusement un procédé de refusion sous laitier électro-conducteur à une pression supérieure à la pression atmosphérique.
Thus, the process for manufacturing the antiferromagnetic alloy according to the invention comprises at least the following successive steps:
  1. a) a step of melting the constituents of the alloy making it possible to form the alloy with the desired metals; this step can for example be carried out in an arc furnace (in particular an electric arc furnace) or a vacuum induction furnace (VIM: vacuum induction melting),
  2. b) a melting of the alloy obtained in step a) making it possible to purify the alloy while limiting the variation in the manganese content, in particular by limiting its evaporation by carrying out this step at a pressure greater than atmospheric pressure. Without being limited to this technique, this step can for example be carried out by a technique of remelting under electroconductive slag under pressure (PESR: pressure electro slag remelting) to allow the dissolution of impurities and inclusions. The purification step is thus carried out by a process involving remelting at a pressure greater than atmospheric pressure, advantageously a process of remelting under electroslag at a pressure greater than atmospheric pressure.

La température Tpur est comprise entre 1250 et 1700 °C, avantageusement entre 1350 et 1500 °C.The pure temperature T is between 1250 and 1700°C, advantageously between 1350 and 1500°C.

En outre, la température de l'étape de fonte des constituants de l'alliage est comprise entre 1250 °C et 1700 °C, avantageusement entre 1350 °C et 1500 °C.Furthermore, the temperature of the step of melting the constituents of the alloy is between 1250°C and 1700°C, advantageously between 1350°C and 1500°C.

Pour l'étape de purification, il est important de noter que le manganèse tend à s'évaporer assez rapidement au-delà d'une certaine température. Or, la teneur de l'alliage final en manganèse étant très importante à l'obtention de certaines propriétés du matériau, il est important de recourir à un procédé limitant son évaporation. Alors que l'évaporation dépend, au-delà d'une certaine température, de la pression d'exposition de la matière au procédé, une étape réalisée sous pression réduit sensiblement la variation de la concentration en manganèse.For the purification step, it is important to note that manganese tends to evaporate quite quickly above a certain temperature. However, the manganese content of the final alloy being very important for obtaining certain properties of the material, it is important to resort to a process limiting its evaporation. While evaporation depends, above a certain temperature, on the pressure of exposure of the material to the process, a step carried out under pressure substantially reduces the variation in manganese concentration.

L'étape de purification opérée à une température T selon la plage énoncée précédemment est réalisée à une pression P supérieure à 10 bar, avantageusement supérieure à 20 bar, et encore plus avantageusement supérieure à 40 bar. La pression P est inférieure ou égale à 50 bar.The purification step carried out at a temperature T according to the range stated above is carried out at a pressure P greater than 10 bar, advantageously greater than 20 bar, and even more advantageously greater than 40 bar. The pressure P is less than or equal to 50 bar.

En revanche, l'étape de fonte n'est pas nécessairement réalisée à une pression supérieure à la pression atmosphérique. Elle peut notamment être réalisée sous vide par exemple dans un four à induction sous vide.On the other hand, the melting step is not necessarily carried out at a pressure greater than atmospheric pressure. It can in particular be carried out under vacuum, for example in a vacuum induction furnace.

Afin d'utiliser cet alliage dans le domaine de l'horlogerie, il est façonné selon les techniques conventionnelles.In order to use this alloy in the field of watchmaking, it is shaped using conventional techniques.

Ainsi, de manière générale, pour former un ressort spiral, un lingot de l'alliage antiferromagnétique est forgé à chaud. Le forgeage du lingot est réalisé à une température inférieure à la température de fusion de l'alliage, préférentiellement inférieure ou égale à 1100 °C. Cependant, la température de forgeage est avantageusement supérieure à 800 °C. Le forgeage permet d'obtenir des barres dont le diamètre est préférentiellement compris entre 10 mm et 40 mm, plus préférentiellement entre 15 mm et 25 mm.Thus, in general, to form a spiral spring, an ingot of the antiferromagnetic alloy is hot forged. The forging of the ingot is carried out at a temperature below the melting temperature of the alloy, preferably less than or equal to 1100°C. However, the forging temperature is advantageously above 800°C. Forging makes it possible to obtain bars whose diameter is preferably between 10 mm and 40 mm, more preferably between 15 mm and 25 mm.

Les barres obtenues par forgeage à chaud sont ensuite laminées à chaud puis à froid jusqu'à un diamètre de 5 mm.The bars obtained by hot forging are then hot and then cold rolled to a diameter of 5 mm.

De manière avantageuse, le laminage est effectué après un traitement thermique à une température préférentiellement comprise entre 800 °C et 1200 °C, plus préférentiellement entre 900 °C et 1100 °C pour abaisser sa dureté.Advantageously, the rolling is carried out after a heat treatment at a temperature preferably between 800° C. and 1200° C., more preferably between 900° C. and 1100° C. to lower its hardness.

Avantageusement, les barres d'un diamètre de 5 mm sont ensuite tréfilées à froid jusqu'au diamètre désiré, avantageusement de l'ordre de 0,5 mm. Au cours du tréfilage, un ou plusieurs traitements thermiques peuvent être mis en œuvre. Ces traitements thermiques sont mis en œuvre à une température avantageusement comprise entre 800 °C et 1200 °C, plus avantageusement entre 900 °C et 1100 °C.Advantageously, the bars with a diameter of 5 mm are then cold drawn to the desired diameter, advantageously of the order of 0.5 mm. During drawing, one or more heat treatments can be implemented. These heat treatments are carried out at a temperature advantageously between 800°C and 1200°C, more advantageously between 900°C and 1100°C.

L'alliage peut ensuite être tréfilé jusqu'à un diamètre final avantageusement inférieur à 100 µm puis laminé, enroulé et fixé pour former un ressort spiral.The alloy can then be drawn to a final diameter advantageously less than 100 μm then rolled, rolled up and fixed to form a spiral spring.

L'invention et les avantages qui en découlent ressortiront mieux des figures et exemples suivants donnés afin d'illustrer l'invention et non de manière limitative.The invention and the resulting advantages will emerge better from the following figures and examples given in order to illustrate the invention and not in a limiting manner.

DESCRIPTION DES FIGURESDESCRIPTION OF FIGURES

  • La figure 1 représente le module d'Young de l'alliage Nivarox (38 à 41 % de nickel, 7,8 à 8 % de chrome, 1,0 % de titane, 0,2 % de silicium, 0,4 % de manganèse, 0,8 à 0,9 % de béryllium, et la balance de fer) en fonction de la température.The figure 1 represents the Young's modulus of the Nivarox alloy (38-41% nickel, 7.8-8% chromium, 1.0% titanium, 0.2% silicon, 0.4% manganese, 0 .8 to 0.9% beryllium, and the balance of iron) depending on the temperature.
  • La figure 2 illustre l'évolution du module d'Young d'un premier alliage INV-1 selon l'invention en fonction de la température, après différents traitements thermiques.The figure 2 illustrates the evolution of the Young's modulus of a first INV-1 alloy according to the invention as a function of temperature, after various heat treatments.
  • La figure 3 illustre l'évolution du module d'Young d'un deuxième alliage INV-2 selon l'invention en fonction de la température, après différents traitements thermiques.The figure 3 illustrates the evolution of the Young's modulus of a second INV-2 alloy according to the invention as a function of temperature, after various heat treatments.
EXEMPLES DE REALISATION DE L'INVENTIONEXAMPLES OF REALIZATION OF THE INVENTION

Deux exemples d'alliages antiferromagnétiques selon l'invention (INV-1 et INV-2 ; tableau 1) ont été préparés selon les étapes suivantes :

  • fonte des constituants de l'alliage,
  • purification de l'alliage,
  • obtention de l'alliage,
  • traitement mécanique (de préférence de forgeage, mais applicable aussi à du tréfilage) et traitement thermique de l'alliage.
Tableau 1 : compositions des alliages selon l'invention INV-1 et INV-2. Eléments (% en poids) INV-1 INV-2 Fer + impuretés résiduelles Balance Balance Manganèse 24,20 30,20 Chrome 9,25 6,90 Vanadium 2,11 2,10 Silicium 0,22 0,22 Carbone 0,51 0,52 Aluminium 0,00 1,10 Two examples of antiferromagnetic alloys according to the invention (INV-1 and INV-2; table 1) were prepared according to the following steps:
  • melting of alloy constituents,
  • purification of the alloy,
  • obtaining the alloy,
  • mechanical treatment (preferably forging, but also applicable to drawing) and heat treatment of the alloy.
Table 1: compositions of the alloys according to the invention INV-1 and INV-2. Elements (% by weight) INV-1 INV-2 Iron + residual impurities Balance Balance Manganese 24.20 30.20 Chromium 9.25 6.90 Vanadium 2.11 2.10 Silicon 0.22 0.22 Carbon 0.51 0.52 Aluminum 0.00 1.10

Les conditions expérimentales du traitement thermique (réalisé après l'étape de purification) sont précisées dans le tableau 2. Tableau 2 : conditions de préparation des alliages selon l'invention INV-1 et INV-2. Conditions INV-1 (figure 2) INV-2 (figure 3) Temps 90 min 90 min Température de fixage 610°C 600°C The experimental conditions of the heat treatment (carried out after the purification step) are specified in Table 2. Table 2: conditions for preparing the alloys according to the invention INV-1 and INV-2. Terms INV-1 ( figure 2 ) INV-2 ( figure 3 ) Time 90 mins 90 mins Fixing temperature 610°C 600°C

A l'issue du procédé d'obtention, c'est-à-dire après la dernière étape de traitement thermique de l'alliage, les deux alliages INV-1 et INV-2 présentent une dureté Vickers de 520 HV et de 460 HV respectivement +/- 30 HV.At the end of the process of obtaining, that is to say after the last stage of heat treatment of the alloy, the two alloys INV-1 and INV-2 have a Vickers hardness of 520 HV and 460 HV respectively +/- 30 HV.

Claims (15)

Alliage antiferromagnétique ayant une composition constituée de : • 15,0 % à 35,0 % en poids de manganèse, • 4,0 % à 15,0 % en poids de chrome, • 1,0 % à 5,0 % en poids de vanadium, • 0,1 % à 2,0 % en poids de carbone, • 0,1 % à 1,0 % en poids de silicium, • 0 % à 2,0 % en poids d'aluminium, • le reste étant du fer et des impuretés résiduelles. Antiferromagnetic alloy having a composition consisting of: • 15.0% to 35.0% by weight of manganese, • 4.0% to 15.0% by weight of chromium, • 1.0% to 5.0% by weight of vanadium, • 0.1% to 2.0% by weight of carbon, • 0.1% to 1.0% by weight of silicon, • 0% to 2.0% by weight aluminum, • the remainder being iron and residual impurities. Alliage selon la revendication 1, caractérisé en ce que la teneur en manganèse est comprise entre 20,0 % et 35,0 % en poids.Alloy according to Claim 1, characterized in that the manganese content is between 20.0% and 35.0% by weight. Alliage selon l'une des revendications 1 ou 2, caractérisé en ce que la teneur en chrome est comprise entre 5,0 % et 12,0 % en poids.Alloy according to one of Claims 1 or 2, characterized in that the chromium content is between 5.0% and 12.0% by weight. Alliage selon l'une des revendications 1 à 3, caractérisé en ce que la teneur en vanadium est comprise entre 1,6 % et 3,5 % en poids.Alloy according to one of Claims 1 to 3, characterized in that the vanadium content is between 1.6% and 3.5% by weight. Alliage selon l'une des revendications 1 à 4, caractérisé en ce que la teneur en carbone est comprise entre 0,1 % et 1,0 % en poids.Alloy according to one of Claims 1 to 4, characterized in that the carbon content is between 0.1% and 1.0% by weight. Alliage selon l'une des revendications 1 à 5, caractérisé en ce que la teneur en silicium est comprise entre 0,1 % et 0,5 % en poids.Alloy according to one of Claims 1 to 5, characterized in that the silicon content is between 0.1% and 0.5% by weight. Alliage selon l'une des revendications 1 à 6, caractérisé en ce que la teneur en aluminium est comprise entre 0,5 % et 2,0 % en poids.Alloy according to one of Claims 1 to 6, characterized in that the aluminum content is between 0.5% and 2.0% by weight. Composant de mouvement horloger au moins en partie constitué d'un alliage selon l'une des revendications 1 à 7.Watch movement component at least partly consisting of an alloy according to one of Claims 1 to 7. Composant selon la revendication 8, caractérisé en ce qu'il s'agit d'un résonateur sous forme de ressort spiral, ou d'un résonateur à lames flexibles, ou d'un résonateur à pivot virtuel.Component according to Claim 8, characterized in that it is a resonator in the form of a spiral spring, or a resonator with flexible blades, or a virtual pivot resonator. Mouvement horloger comprenant au moins un composant selon l'une des revendications 8 ou 9.Watch movement comprising at least one component according to one of Claims 8 or 9. Montre comprenant un mouvement horloger selon la revendication 10.Watch comprising a horological movement according to claim 10. Procédé pour réaliser un alliage selon l'une des revendications 1 à 7, comportant notamment les étapes successives suivantes : • une étape de fonte des constituants de l'alliage, réalisée en une ou plusieurs phases et à une température Tfon, permettant de former l'alliage contenant les métaux désirés, la température Tfon étant comprise entre 1250 °C et 1700 °C, • une étape de purification, réalisée en une ou plusieurs phases, permettant d'enlever les impuretés des constituants de l'alliage tout en limitant l'évaporation de manganèse, et opérée à une température Tpur et à une pression P supérieure à 10 bar et inférieure ou égale à 50 bar, la température Tpur étant comprise entre 1250 °C et 1700 °C. Process for producing an alloy according to one of Claims 1 to 7, comprising in particular the following successive steps: • a step of melting the constituents of the alloy, carried out in one or more phases and at a temperature T fon , making it possible to form the alloy containing the desired metals, the temperature T fon being between 1250°C and 1700°C , • a purification step, carried out in one or more phases, allowing the impurities of the constituents of the alloy to be removed while limiting the evaporation of manganese, and carried out at a pure temperature T and at a pressure P greater than 10 bar and less than or equal to 50 bar, the pure temperature T being between 1250°C and 1700°C. Procédé selon la revendication 12, caractérisé en ce que, à l'issue de l'étape de purification, l'alliage présente une teneur totale en impuretés inférieure ou égale à 3000 ppm.Process according to Claim 12, characterized in that , at the end of the purification stage, the alloy has a total impurity content of less than or equal to 3000 ppm. Procédé selon l'une des revendications 12 à 13, caractérisé en ce que la température Tpur de l'étape de purification est comprise entre 1350 °C et 1500 °C, et en ce que la température Tfon de l'étape de fonte des constituants de l'alliage est comprise entre 1350 °C et 1500°C.Process according to one of Claims 12 to 13, characterized in that the temperature T pur of the purification stage is between 1350°C and 1500°C, and in that the temperature T fon of the melting stage of the constituents of the alloy is between 1350°C and 1500°C. Procédé selon l'une des revendications 12 à 14, caractérisé en ce que l'étape de purification est réalisée à une pression P supérieure à 20 bar et avantageusement inférieure ou égale à 50 bar.Process according to one of Claims 12 to 14, characterized in that the purification stage is carried out at a pressure P greater than 20 bar and advantageously less than or equal to 50 bar.
EP21155159.3A 2021-02-04 2021-02-04 Non ferromagnetic alloy, manufacturing proccess therefore and clock movement component made of that alloy Withdrawn EP4039843A1 (en)

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EP21155159.3A EP4039843A1 (en) 2021-02-04 2021-02-04 Non ferromagnetic alloy, manufacturing proccess therefore and clock movement component made of that alloy
EP22703324.8A EP4288577A1 (en) 2021-02-04 2022-01-27 Antiferromagnetic alloy, method for the production thereof and timepiece movement component made from the alloy
PCT/EP2022/051955 WO2022167327A1 (en) 2021-02-04 2022-01-27 Antiferromagnetic alloy, method for the production thereof and timepiece movement component made from the alloy

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