EP3796101A1 - Hairspring for clock movement - Google Patents

Hairspring for clock movement Download PDF

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Publication number
EP3796101A1
EP3796101A1 EP19198759.3A EP19198759A EP3796101A1 EP 3796101 A1 EP3796101 A1 EP 3796101A1 EP 19198759 A EP19198759 A EP 19198759A EP 3796101 A1 EP3796101 A1 EP 3796101A1
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EP
European Patent Office
Prior art keywords
spiral spring
deformation
titanium
weight
manufacturing
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.)
Pending
Application number
EP19198759.3A
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German (de)
French (fr)
Inventor
Christian Charbon
Marco Verardo
Lionel MICHELET
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.)
Nivarox Far SA
Nivarox SA
Original Assignee
Nivarox Far SA
Nivarox SA
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Publication date
Application filed by Nivarox Far SA, Nivarox SA filed Critical Nivarox Far SA
Priority to EP19198759.3A priority Critical patent/EP3796101A1/en
Priority to US16/936,682 priority patent/US20210088971A1/en
Priority to JP2020136578A priority patent/JP7148577B2/en
Priority to CN202210710467.XA priority patent/CN114990402A/en
Priority to CN202010985588.6A priority patent/CN112538587B/en
Publication of EP3796101A1 publication Critical patent/EP3796101A1/en
Pending legal-status Critical Current

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    • 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
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C27/00—Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
    • C22C27/02—Alloys based on vanadium, niobium, or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/002—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working by rapid cooling or quenching; cooling agents used therefor
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/02—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working in inert or controlled atmosphere or vacuum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
    • C22F1/18—High-melting or refractory metals or alloys based thereon
    • 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
    • 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
    • G04B17/063—Balance construction

Definitions

  • the invention relates to a spiral spring intended to equip a balance of a clockwork movement. It also relates to the method of manufacturing this spiral spring.
  • the invention proposes to define a new type of clockwork spiral spring, based on the selection of a particular material, and to develop the appropriate manufacturing process.
  • the invention relates to a clockwork spiral spring made from an alloy of niobium and titanium.
  • the titanium content is between 1% (limit included) and 40% (limit not included) by weight.
  • it is between 5 and 35% by weight (limits included), preferably between 15 and 35% (limits included) and more preferably between 27 and 33% (limits included).
  • the remainder consists of niobium and impurities including interstitials such as H, C, N and / or O, the percentage of impurities being less than or equal to 0.3% by weight.
  • the invention also relates to the method of manufacturing this clockwork spiral spring as claimed in the appendix.
  • the invention relates to a clockwork spiral spring made from a binary type alloy comprising niobium and titanium.
  • the percentage by weight of oxygen is less than or equal to 0.10% of the total, or even less than or equal to 0.085% of the total.
  • the percentage by weight of tantalum is less than or equal to 0.10% of the total.
  • the percentage by weight of carbon is less than or equal to 0.04% of the total, in particular less than or equal to 0.020% of the total, or even less than or equal to 0.0175% of the total.
  • the percentage by weight of iron is less than or equal to 0.03% of the total, in particular less than or equal to 0.025% of the total, or even less than or equal to 0.020% of the total.
  • the percentage by weight of nitrogen is less than or equal to 0.02% of the total, in particular less than or equal to 0.015% of the total, or even less than or equal to 0.0075% of the total.
  • the percentage by weight of hydrogen is less than or equal to 0.01% of the total, in particular less than or equal to 0.0035% of the total, or even less than or equal to 0.0005% of the total.
  • the percentage by weight of nickel is less than or equal to 0.01% of the total.
  • the percentage by weight of silicon is less than or equal to 0.01% of the total.
  • the percentage by weight of nickel is less than or equal to 0.01% of the total, in particular less than or equal to 0.16% of the total.
  • the percentage by weight of copper is less than or equal to 0.01% of the total, in particular less than or equal to 0.005% of the total.
  • the percentage by weight of aluminum is less than or equal to 0.01% of the total.
  • this spiral spring has a two-phase microstructure comprising niobium in the centered cubic beta phase and titanium in the compact hexagonal alpha phase.
  • thermoelastic coefficient also called CTE of the alloy
  • CTE the thermoelastic coefficient
  • dM dT 1 2 E of dT - ⁇ + 3 2 ⁇ ⁇ 86400 s j ° C
  • M and T are respectively the rate and the temperature.
  • E is the Young's modulus of the spiral spring, and, in this formula, E, ⁇ and ⁇ are expressed in ° C -1 .
  • CT is the thermal coefficient of the oscillator, (1 / E.
  • DE / dT DE / dT
  • ⁇ is the expansion coefficient of the balance and ⁇ that of the balance spring.
  • the hardened beta-phase alloy exhibits a strongly positive CTE, and the precipitation of the alpha phase which has a strongly negative CTE makes it possible to bring the two-phase alloy to a CTE close to zero, which is particularly favorable.
  • too high a percentage of titanium leads to the formation of brittle phases.
  • a percentage of titanium less than 40% by weight makes it possible to obtain a good compromise between the various desired properties.
  • the interaction between dislocations and C, H, N, O interstitials present in the alloy as well as the interaction between dislocations and alpha titanium precipitates also play a favorable role on CTE. .
  • the setting in motion of the dislocations as a function of the temperature causes a reduction in the Young's modulus of the spiral spring which counteracts the positive anomaly of the beta phase.
  • the spiral spring produced with this alloy has an elastic limit greater than or equal to 500 MPa and more precisely between 500 and 1000 MPa.
  • it has a modulus of elasticity less than or equal to 120 GPa and preferably less than or equal to 110 GPa.
  • each strain is performed with a given strain rate between 1 and 5, this strain rate corresponding to the classic formula 2ln (d0 / d), where d0 is the diameter of the last beta hardening, and where d is the diameter of the hardened wire.
  • the global accumulation of the deformations over the whole of this succession of sequences brings a total rate of deformation of between 1 and 14.
  • Each coupled sequence of deformation-heat treatment comprises, each time, a heat treatment of precipitation of the alpha Ti phase. .
  • Beta quenching prior to the deformation and heat treatment sequences is a solution treatment, with a duration of between 5 minutes and 2 hours at a temperature between 700 ° C and 1000 ° C, under vacuum, followed by a gas cooling.
  • this beta quenching is a solution treatment, for 1 hour at 800 ° C. under vacuum, followed by cooling under gas.
  • the heat treatment is a precipitation treatment lasting between 1 hour and 200 hours at a temperature between 300 ° C and 700 ° C. More particularly, the duration is between 5 hours and 30 hours at a temperature between 400 ° C and 600 ° C.
  • the method comprises between one and five coupled sequences of deformation-heat treatment.
  • the first coupled strain-heat treatment sequence comprises a first strain with at least 30% reduction in section.
  • each coupled sequence of heat-treatment-strain comprises a strain between two heat treatments with at least 25% reduction in section.
  • a surface layer of ductile material is added to the blank, taken from among copper, nickel, cupro- nickel, cupro-magnanese, gold, silver, nickel-phosphorus Ni-P and nickel-boron Ni-B, or the like, to facilitate forming into a wire shape during deformation.
  • the wire is freed from its layer of ductile material, in particular by chemical attack.
  • the surface layer of ductile material is deposited so as to constitute a spiral spring, the pitch of which is not a multiple of the thickness of the blade.
  • the surface layer of ductile material is deposited so as to constitute a spring whose pitch is variable.
  • ductile material or copper is thus added at a given moment to facilitate the shaping in the form of wire, so that a thickness of 10 to 500 micrometers remains on the wire. with a final diameter of 0.3 to 1 millimeters.
  • the wire is stripped of its layer of ductile or copper material in particular by chemical attack, then is rolled flat before the manufacture of the spring proper by slipping.
  • the supply of ductile or copper material can be galvanic, or else mechanical, it is then a jacket or a tube of ductile or copper material. which is fitted to a large diameter niobium-titanium alloy bar, and then which is thinned during the deformation steps of the composite bar.
  • a diffusion barrier layer for example nb, can be added between the nb-Ti and the Cu in order to avoid the formation of intermetallics which are harmful to the deformability of the material.
  • the thickness of this layer is chosen so as to correspond to a thickness of 100 nm to 1 ⁇ m on the wire with a diameter of 0.1 mm.
  • the layer can be removed in particular by chemical attack, with a solution based on cyanides or based on acids, for example nitric acid.
  • a very fine two-phase lamellar microstructure in particular nanometric, comprising or composed of beta niobium and alpha titanium.
  • This alloy combines a very high elastic limit, greater than at least 500 MPa, and a very low modulus of elasticity, of the order of 80 GPa to 120 GPa. This combination of properties works well for a spiral spring.
  • the alloy after the deformation-heat treatment sequences exhibits a ⁇ 110> texture.
  • this niobium-titanium alloy according to the invention can easily be covered with ductile material or copper, which greatly facilitates its deformation by drawing.
  • a binary type alloy comprising niobium and titanium, of the type selected above for the implementation of the invention, also exhibits an effect similar to that of "Elinvar", with a thermoelastic coefficient practically zero. within the temperature range of usual use of watches, and suitable for the manufacture of self-compensating balance springs.

Abstract

La présente invention concerne un ressort spiral (1) destiné à équiper un balancier d'un mouvement d'horlogerie, caractérisé en ce que le ressort spiral (1) est réalisé dans un alliage de niobium et de titane constitué en poids de:
- niobium : balance à 100% ;
- titane avec un pourcentage supérieur ou égal à 1% et inférieur à 40% ;
- des traces d'autres éléments choisis parmi O, H, C, Fe, Ta, N, Ni, Si, Cu, Al, chacun desdits éléments étant compris entre 0 et 1600 ppm du total en poids et la somme desdites traces étant inférieure ou égale à 0.3% en poids.The present invention relates to a spiral spring (1) intended to equip a balance of a timepiece movement, characterized in that the spiral spring (1) is made of an alloy of niobium and titanium consisting by weight of:
- niobium: balance at 100%;
- titanium with a percentage greater than or equal to 1% and less than 40%;
- traces of other elements chosen from O, H, C, Fe, Ta, N, Ni, Si, Cu, Al, each of said elements being between 0 and 1600 ppm of the total by weight and the sum of said traces being less or equal to 0.3% by weight.

La présente invention concerne également son procédé de fabrication.

Figure imgaf001
The present invention also relates to its manufacturing process.
Figure imgaf001

Description

Domaine de l'inventionField of the invention

L'invention concerne un ressort spiral destiné à équiper un balancier d'un mouvement d'horlogerie. Elle se rapporte également au procédé de fabrication de ce ressort spiral.The invention relates to a spiral spring intended to equip a balance of a clockwork movement. It also relates to the method of manufacturing this spiral spring.

Arrière-plan de l'inventionBackground of the invention

La fabrication de ressorts spiraux pour l'horlogerie doit faire face à des contraintes souvent à première vue incompatibles :

  • nécessité d'obtention d'une limite élastique élevée,
  • facilité d'élaboration, notamment de tréfilage et de laminage,
  • excellente tenue en fatigue,
  • stabilité des performances dans le temps,
  • faibles sections.
The manufacture of spiral springs for watchmaking must face constraints that are often incompatible at first glance:
  • need to obtain a high elastic limit,
  • ease of production, especially wire drawing and rolling,
  • excellent fatigue resistance,
  • performance stability over time,
  • low sections.

La réalisation de ressorts spiraux est en outre centrée sur le souci de la compensation thermique, de façon à garantir des performances chronométriques régulières. Il faut pour cela obtenir un coefficient thermoélastique proche de zéro.The production of spiral springs is also centered on the concern for thermal compensation, so as to guarantee regular chronometric performance. This requires obtaining a thermoelastic coefficient close to zero.

Toute amélioration sur au moins l'un des points, et en particulier sur la tenue mécanique de l'alliage utilisé, représente donc une avancée significative.Any improvement on at least one of the points, and in particular on the mechanical strength of the alloy used, therefore represents a significant advance.

Résumé de l'inventionSummary of the invention

L'invention se propose de définir un nouveau type de ressort spiral d'horlogerie, basé sur la sélection d'un matériau particulier, et de mettre au point le procédé de fabrication adéquat.The invention proposes to define a new type of clockwork spiral spring, based on the selection of a particular material, and to develop the appropriate manufacturing process.

A cet effet, l'invention concerne un ressort spiral d'horlogerie réalisé dans un alliage de niobium et de titane. Selon l'invention, la teneur en titane est comprise en poids entre 1% (borne comprise) et 40% (borne non comprise). Avantageusement, elle est comprise en poids entre 5 et 35% (bornes comprises), de préférence entre 15 et 35% (bornes comprises) et plus préférentiellement entre 27 et 33% (bornes comprises). Le reste est constitué de niobium et d'impuretés dont des interstitiels tels que H, C, N et/ou O, le pourcentage d'impuretés étant inférieur ou égal à 0.3% en poids.To this end, the invention relates to a clockwork spiral spring made from an alloy of niobium and titanium. According to the invention, the titanium content is between 1% (limit included) and 40% (limit not included) by weight. Advantageously, it is between 5 and 35% by weight (limits included), preferably between 15 and 35% (limits included) and more preferably between 27 and 33% (limits included). The remainder consists of niobium and impurities including interstitials such as H, C, N and / or O, the percentage of impurities being less than or equal to 0.3% by weight.

L'invention concerne également le procédé de fabrication de ce ressort spiral d'horlogerie tel que revendiqué en annexe.The invention also relates to the method of manufacturing this clockwork spiral spring as claimed in the appendix.

Description sommaire des dessinsBrief description of the drawings

D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture de la description détaillée qui va suivre, en référence aux dessins annexés, où :

  • la figure 1 représente, de façon schématisée, un ressort spiral réalisé avec un alliage Nb-Ti selon l'invention ;
  • la figure 2 représente les courbes d'évolution du module de Young en fonction de la température rapporté sur le module de Young à 20°C pour respectivement le Nb pur et un alliage Nb-Ti selon l'invention avec 30% en poids de Ti.
Other characteristics and advantages of the invention will become apparent on reading the detailed description which follows, with reference to the appended drawings, where:
  • the figure 1 represents, schematically, a spiral spring produced with an Nb-Ti alloy according to the invention;
  • the figure 2 represents the evolution curves of the Young's modulus as a function of the temperature relative to the Young's modulus at 20 ° C. for respectively pure Nb and an Nb-Ti alloy according to the invention with 30% by weight of Ti.

Description détaillée des modes de réalisation préférésDetailed description of the preferred embodiments

L'invention concerne un ressort spiral d'horlogerie réalisé dans un alliage de type binaire comportant du niobium et du titane.The invention relates to a clockwork spiral spring made from a binary type alloy comprising niobium and titanium.

Selon l'invention, cet alliage comporte en poids:

  • du niobium : balance à 100% ;
  • du titane dans un pourcentage supérieur ou égal à 1% et inférieur à 40%. Plus particulièrement, cet alliage comporte une proportion en poids de titane comprise entre 5 et 35%, de préférence entre 15 et 35% et plus préférentiellement entre 27 et 33% ;
  • des traces d'autres éléments choisis parmi O, H, C, Fe, Ta, N, Ni, Si, Cu et/ou Al, chacun desdits éléments étant compris entre 0 et 1600 ppm du total en poids, et la somme de ces traces étant inférieure ou égale à 0.3%. En d'autres mots, le total des pourcentages en poids du titane et du niobium est compris entre 99.7% et 100% du total.
According to the invention, this alloy comprises by weight:
  • niobium: 100% balance;
  • titanium in a percentage greater than or equal to 1% and less than 40%. More particularly, this alloy comprises a proportion by weight of titanium of between 5 and 35%, preferably between 15 and 35% and more preferably between 27 and 33%;
  • traces of other elements chosen from O, H, C, Fe, Ta, N, Ni, Si, Cu and / or Al, each of said elements being between 0 and 1600 ppm of the total by weight, and the sum of these traces being less than or equal to 0.3%. In other words, the total of the percentages by weight of titanium and niobium is between 99.7% and 100% of the total.

Le pourcentage en poids d'oxygène est inférieur ou égal à 0.10% du total, voire encore inférieur ou égal à 0.085% du total.The percentage by weight of oxygen is less than or equal to 0.10% of the total, or even less than or equal to 0.085% of the total.

Le pourcentage en poids de tantale est inférieur ou égal à 0.10% du total.The percentage by weight of tantalum is less than or equal to 0.10% of the total.

Le pourcentage en poids de carbone est inférieur ou égal à 0.04% du total, notamment inférieur ou égal à 0.020% du total, voire encore inférieur ou égal à 0.0175% du total.The percentage by weight of carbon is less than or equal to 0.04% of the total, in particular less than or equal to 0.020% of the total, or even less than or equal to 0.0175% of the total.

Le pourcentage en poids de fer est inférieur ou égal à 0.03% du total, notamment inférieur ou égal à 0.025% du total, voire encore inférieur ou égal à 0.020% du total.The percentage by weight of iron is less than or equal to 0.03% of the total, in particular less than or equal to 0.025% of the total, or even less than or equal to 0.020% of the total.

Le pourcentage en poids d'azote est inférieur ou égal à 0.02% du total, notamment inférieur ou égal à 0.015% du total, voire encore inférieur ou égal à 0.0075% du total.The percentage by weight of nitrogen is less than or equal to 0.02% of the total, in particular less than or equal to 0.015% of the total, or even less than or equal to 0.0075% of the total.

Le pourcentage en poids d'hydrogène est inférieur ou égal à 0.01 % du total, notamment inférieur ou égal à 0.0035% du total, voire encore inférieur ou égal à 0.0005% du total.The percentage by weight of hydrogen is less than or equal to 0.01% of the total, in particular less than or equal to 0.0035% of the total, or even less than or equal to 0.0005% of the total.

Le pourcentage en poids de nickel est inférieur ou égal à 0.01% du total.The percentage by weight of nickel is less than or equal to 0.01% of the total.

Le pourcentage en poids de silicium est inférieur ou égal à 0.01% du total.The percentage by weight of silicon is less than or equal to 0.01% of the total.

Le pourcentage en poids de nickel est inférieur ou égal à 0.01% du total, notamment inférieur ou égal à 0.16% du total.The percentage by weight of nickel is less than or equal to 0.01% of the total, in particular less than or equal to 0.16% of the total.

Le pourcentage en poids de cuivre est inférieur ou égal à 0.01 % du total, notamment inférieur ou égal à 0.005% du total.The percentage by weight of copper is less than or equal to 0.01% of the total, in particular less than or equal to 0.005% of the total.

Le pourcentage en poids d'aluminium est inférieur ou égal à 0.01 % du total.The percentage by weight of aluminum is less than or equal to 0.01% of the total.

De façon avantageuse, ce ressort spiral a une microstructure bi-phasée comportant du niobium en phase bêta cubique centré et du titane en phase alpha hexagonal compact.Advantageously, this spiral spring has a two-phase microstructure comprising niobium in the centered cubic beta phase and titanium in the compact hexagonal alpha phase.

Pour obtenir une telle microstructure, et convenant à l'élaboration d'un ressort, il est nécessaire de précipiter une partie de la phase alpha par traitement thermique.To obtain such a microstructure, and suitable for the development of a spring, it is necessary to precipitate part of the alpha phase by heat treatment.

Plus le taux de titane est élevé, plus la proportion maximale de phase alpha qui peut être précipitée par traitement thermique est élevée, ce qui incite à rechercher une forte proportion de titane. Mais a contrario, plus le taux de titane est élevé, plus il est difficile d'obtenir uniquement une précipitation de la phase alpha aux joints de grains. L'apparition de précipités de type Widmastätten alpha-Ti intragranulaire ou la phase w intragranulaire rend la déformation du matériau difficile, voire impossible, ce qui ne convient alors pas à la réalisation d'un ressort spiral, et il convient alors de ne pas incorporer trop de titane dans l'alliage. En outre, l'application de cet alliage à un ressort spiral nécessite des propriétés aptes à garantir le maintien des performances chronométriques malgré la variation des températures d'utilisation d'une montre incorporant un tel ressort spiral. Le coefficient thermoélastique, dit aussi CTE de l'alliage, a alors une grande importance. Pour former un oscillateur chronométrique avec un balancier en CuBe ou en maillechort, un CTE de +/- 10 ppm/°C doit être atteint. La formule qui lie le CTE de l'alliage et les coefficients de dilatation du spiral et du balancier est la suivante : CT = dM dT = 1 2 E dE dT − β + 3 2 α × 86400 s j°C

Figure imgb0001
Les variables M et T sont respectivement la marche et la température. E est le module de Young du ressort spiral, et, dans cette formule, E, β et α s'expriment en °C-1.
CT est le coefficient thermique de l'oscillateur, (1/E. dE/dT) est le CTE de l'alliage spiral, β est le coefficient de dilatation du balancier et α celui du spiral. L'alliage en phase bêta écroui présente un CTE fortement positif, et la précipitation de la phase alpha qui possède un CTE fortement négatif permet de ramener l'alliage biphasé à un CTE proche de zéro, ce qui est particulièrement favorable. Cependant, comme mentionné plus haut, un pourcentage trop élevé de titane mène à la formation de phases fragiles. Un pourcentage de titane inférieur à 40% en poids permet d'obtenir un bon compromis entre les différentes propriétés recherchées. Il est par ailleurs supposé que l'interaction entre les dislocations et les interstitiels C, H, N, O présents dans l'alliage de même que l'interaction entre les dislocations et les précipités de titane alpha jouent également un rôle favorable sur le CTE. La mise en mouvement des dislocations en fonction de la température provoque une diminution du module de Young du ressort spiral qui contrecarre l'anomalie positive de la phase bêta.The higher the titanium content, the higher the maximum proportion of alpha phase which can be precipitated by heat treatment, which encourages the search for a high proportion of titanium. But conversely, the higher the titanium content, the more difficult it is to obtain only a precipitation of the alpha phase at the grain boundaries. The appearance of intragranular Widmastätten alpha-Ti type precipitates or the intragranular w phase makes the deformation of the material difficult, if not impossible, which is then not suitable for the production of a spiral spring, and it is then advisable not to incorporate too much titanium in the alloy. In addition, the application of this alloy to a spiral spring requires properties capable of guaranteeing the maintenance of chronometric performance despite the variation in temperatures of use of a watch incorporating such a spiral spring. The thermoelastic coefficient, also called CTE of the alloy, is then of great importance. To form a chronometric oscillator with a CuBe or nickel silver balance, a CTE of +/- 10 ppm / ° C must be achieved. The formula which links the CTE of the alloy and the coefficients of expansion of the hairspring and balance is as follows: CT = dM dT = 1 2 E of dT - β + 3 2 α × 86400 s j ° C
Figure imgb0001
 The variables M and T are respectively the rate and the temperature. E is the Young's modulus of the spiral spring, and, in this formula, E, β and α are expressed in ° C -1 .
CT is the thermal coefficient of the oscillator, (1 / E. DE / dT) is the CTE of the balance spring alloy, β is the expansion coefficient of the balance and α that of the balance spring. The hardened beta-phase alloy exhibits a strongly positive CTE, and the precipitation of the alpha phase which has a strongly negative CTE makes it possible to bring the two-phase alloy to a CTE close to zero, which is particularly favorable. However, as mentioned above, too high a percentage of titanium leads to the formation of brittle phases. A percentage of titanium less than 40% by weight makes it possible to obtain a good compromise between the various desired properties. It is also assumed that the interaction between dislocations and C, H, N, O interstitials present in the alloy as well as the interaction between dislocations and alpha titanium precipitates also play a favorable role on CTE. . The setting in motion of the dislocations as a function of the temperature causes a reduction in the Young's modulus of the spiral spring which counteracts the positive anomaly of the beta phase.

Le ressort spiral élaboré avec cet alliage a une limite élastique supérieure ou égale à 500 MPa et plus précisément comprise entre 500 et 1000 MPa. De façon avantageuse, il a un module d'élasticité inférieur ou égal à 120 GPa et de préférence inférieur ou égal à 110 GPa.The spiral spring produced with this alloy has an elastic limit greater than or equal to 500 MPa and more precisely between 500 and 1000 MPa. Advantageously, it has a modulus of elasticity less than or equal to 120 GPa and preferably less than or equal to 110 GPa.

L'invention concerne également le procédé de fabrication du ressort spiral d'horlogerie, caractérisé en ce qu'on met en œuvre successivement les étapes suivantes :

  • élaboration d'une ébauche dans un alliage comportant du niobium et du titane et plus précisément :
    • du niobium : balance à 100% ;
    • un pourcentage en poids de titane supérieur ou égal à 1% du total et inférieur à 40% du total ;
    • des traces d'autres éléments choisis parmi O, H, C, Fe, Ta, N, Ni, Si, Cu, Al, chacun desdits éléments étant compris entre 0 et 1600 ppm du total en poids, et la somme desdites traces étant inférieure ou égale à 0.3% en poids;
  • une trempe de type bêta de ladite ébauche, de façon à ce que le titane dudit alliage soit essentiellement sous forme de solution solide avec le niobium en phase bêta ;
  • application audit alliage de séquences de déformation suivie d'un traitement thermique. On entend par déformation une déformation par tréfilage et/ou laminage. Le tréfilage peut nécessiter l'utilisation d'une ou plusieurs filières lors d'une même séquence ou lors de différentes séquences si nécessaire. Le tréfilage est réalisé jusqu'à l'obtention d'un fil de section ronde. Le laminage peut être effectué lors de la même séquence de déformation que le tréfilage ou dans une autre séquence. Avantageusement, la dernière séquence appliquée à l'alliage est un laminage de préférence à profil rectangulaire compatible avec la section d'entrée d'une broche d'estrapadage. Ces séquences mènent à l'obtention d'une microstructure bi-phasée comportant du niobium bêta et du titane alpha, avec une limite élastique supérieure ou égale à 500 MPa et un module d'élasticité inférieur ou égal à 120 GPa et de préférence à 110 GPa.
  • estrapadage pour former un ressort spiral, suivi d'un traitement thermique final.
The invention also relates to the method of manufacturing the clockwork spiral spring, characterized in that the following steps are successively implemented:
  • preparation of a blank in an alloy comprising niobium and titanium and more precisely:
    • niobium: 100% balance;
    • a percentage by weight of titanium greater than or equal to 1% of the total and less than 40% of the total;
    • traces of other elements chosen from O, H, C, Fe, Ta, N, Ni, Si, Cu, Al, each of said elements being between 0 and 1600 ppm of the total by weight, and the sum of said traces being less or equal to 0.3% by weight;
  • beta-type quenching of said blank, so that the titanium of said alloy is essentially in the form of a solid solution with the niobium in the beta phase;
  • application to said alloy of deformation sequences followed by heat treatment. By deformation is meant a deformation by wire drawing and / or rolling. Wire drawing may require the use of one or more dies during the same sequence or during different sequences if necessary. The wire drawing is carried out until a wire of round section is obtained. Rolling can be done in the same strain sequence as wire drawing or in a different sequence. Advantageously, the last sequence applied to the alloy is a rolling preferably with a rectangular profile compatible with the entry section of a stepping spindle. These sequences lead to obtaining a two-phase microstructure comprising beta niobium and alpha titanium, with a limit elastic greater than or equal to 500 MPa and an elastic modulus less than or equal to 120 GPa and preferably 110 GPa.
  • slipping to form a spiral spring, followed by a final heat treatment.

Dans ces séquences couplées de déformation-traitement thermique, chaque déformation est effectuée avec un taux de déformation donné compris entre 1 et 5, ce taux de déformation répondant à la formule classique 2ln(d0/d), où d0 est le diamètre de la dernière trempe bêta, et où d est le diamètre du fil écroui. Le cumul global des déformations sur l'ensemble de cette succession de séquences amène un taux total de déformation compris entre 1 et 14. Chaque séquence couplée de déformation-traitement thermique comporte, à chaque fois, un traitement thermique de précipitation de la phase alpha Ti.In these coupled sequences of strain-heat treatment, each strain is performed with a given strain rate between 1 and 5, this strain rate corresponding to the classic formula 2ln (d0 / d), where d0 is the diameter of the last beta hardening, and where d is the diameter of the hardened wire. The global accumulation of the deformations over the whole of this succession of sequences brings a total rate of deformation of between 1 and 14. Each coupled sequence of deformation-heat treatment comprises, each time, a heat treatment of precipitation of the alpha Ti phase. .

La trempe bêta préalable aux séquences de déformation et de traitement thermique est un traitement de mise en solution, avec une durée comprise entre 5 minutes et 2 heures à une température comprise entre 700°C et 1000°C, sous vide, suivie d'un refroidissement sous gaz.Beta quenching prior to the deformation and heat treatment sequences is a solution treatment, with a duration of between 5 minutes and 2 hours at a temperature between 700 ° C and 1000 ° C, under vacuum, followed by a gas cooling.

Plus particulièrement encore, cette trempe bêta est un traitement de mise en solution, d'1 heure à 800°C sous vide, suivie d'un refroidissement sous gaz.More particularly still, this beta quenching is a solution treatment, for 1 hour at 800 ° C. under vacuum, followed by cooling under gas.

Pour revenir aux séquences couplées de déformation-traitement thermique, le traitement thermique est un traitement de précipitation d'une durée comprise entre 1 heure et 200 heures à une température comprise entre 300°C et 700°C. Plus particulièrement, la durée est comprise entre 5 heures et 30 heures à une température comprise entre 400°C et 600°C.To return to the coupled deformation-heat treatment sequences, the heat treatment is a precipitation treatment lasting between 1 hour and 200 hours at a temperature between 300 ° C and 700 ° C. More particularly, the duration is between 5 hours and 30 hours at a temperature between 400 ° C and 600 ° C.

Plus particulièrement, le procédé comporte entre une et cinq séquences couplées de déformation-traitement thermique.More particularly, the method comprises between one and five coupled sequences of deformation-heat treatment.

Plus particulièrement, la première séquence couplée de déformation-traitement thermique comporte une première déformation avec au moins 30 % de réduction de section.More particularly, the first coupled strain-heat treatment sequence comprises a first strain with at least 30% reduction in section.

Plus particulièrement, chaque séquence couplée de déformation-traitement thermique, autre que la première, comporte une déformation entre deux traitements thermiques avec au moins 25 % de réduction de section.More particularly, each coupled sequence of heat-treatment-strain, other than the first, comprises a strain between two heat treatments with at least 25% reduction in section.

Plus particulièrement, après cette élaboration de ladite ébauche en alliage, et avant les séquences de déformation-traitement thermique, dans une étape supplémentaire, on ajoute à l'ébauche une couche superficielle de matériau ductile pris parmi le cuivre, le nickel, le cupro-nickel, le cupro-magnanèse, l'or, l'argent, le nickel-phosphore Ni-P et le nickel-bore Ni-B, ou similaire, pour faciliter la mise en forme sous forme de fil lors de la déformation. Et, après les séquences de déformation-traitement thermique ou après l'étape d'estrapadage, on débarrasse le fil de sa couche du matériau ductile, notamment par attaque chimique.More particularly, after this preparation of said alloy blank, and before the deformation-heat treatment sequences, in an additional step, a surface layer of ductile material is added to the blank, taken from among copper, nickel, cupro- nickel, cupro-magnanese, gold, silver, nickel-phosphorus Ni-P and nickel-boron Ni-B, or the like, to facilitate forming into a wire shape during deformation. And, after the deformation-heat treatment sequences or after the stripping step, the wire is freed from its layer of ductile material, in particular by chemical attack.

Dans une variante, on dépose la couche superficielle de matériau ductile de façon à constituer un ressort spiral dont le pas n'est pas un multiple de l'épaisseur de la lame. Dans une autre variante, on dépose la couche superficielle de matériau ductile de façon à constituer un ressort dont le pas est variable.In a variant, the surface layer of ductile material is deposited so as to constitute a spiral spring, the pitch of which is not a multiple of the thickness of the blade. In another variant, the surface layer of ductile material is deposited so as to constitute a spring whose pitch is variable.

Dans une application horlogère particulière, du matériau ductile ou du cuivre est ainsi ajouté à un moment donné pour faciliter la mise en forme sous forme de fil, de telle manière à ce qu'il en reste une épaisseur de 10 à 500 micromètres sur le fil au diamètre final de 0.3 à 1 millimètres. Le fil est débarrassé de sa couche de matériau ductile ou cuivre notamment par attaque chimique, puis est laminé à plat avant la fabrication du ressort proprement dit par estrapadage.In a particular horological application, ductile material or copper is thus added at a given moment to facilitate the shaping in the form of wire, so that a thickness of 10 to 500 micrometers remains on the wire. with a final diameter of 0.3 to 1 millimeters. The wire is stripped of its layer of ductile or copper material in particular by chemical attack, then is rolled flat before the manufacture of the spring proper by slipping.

L'apport de matériau ductile ou cuivre peut être galvanique, ou bien mécanique, c'est alors une chemise ou un tube de matériau ductile ou cuivre qui est ajusté sur une barre d'alliage niobium-titane à un gros diamètre, puis qui est amincie au cours des étapes de déformation du barreau composite.The supply of ductile or copper material can be galvanic, or else mechanical, it is then a jacket or a tube of ductile or copper material. which is fitted to a large diameter niobium-titanium alloy bar, and then which is thinned during the deformation steps of the composite bar.

Une couche barrière de diffusion, par exemple du nb, peut être ajoutée entre le nb-Ti et le Cu afin d'éviter la formation d'intermétalliques néfastes à la déformabilité du matériau. L'épaisseur de cette couche est choisie de manière à correspondre à une épaisseur de 100 nm à 1 µm sur le fil à diamètre 0.1 mm.A diffusion barrier layer, for example nb, can be added between the nb-Ti and the Cu in order to avoid the formation of intermetallics which are harmful to the deformability of the material. The thickness of this layer is chosen so as to correspond to a thickness of 100 nm to 1 μm on the wire with a diameter of 0.1 mm.

L'enlèvement de la couche est notamment réalisable par attaque chimique, avec une solution à base de cyanures ou à base d'acides, par exemple d'acide nitrique.The layer can be removed in particular by chemical attack, with a solution based on cyanides or based on acids, for example nitric acid.

Par une combinaison adéquate de séquences de déformation et de traitement thermique, il est possible d'obtenir une microstructure bi-phasée lamellaire très fine, en particulier nanométrique, comportant ou composée de niobium bêta et de titane alpha. Cet alliage combine une limite élastique très élevée, supérieure au moins à 500 MPa et un module d'élasticité très bas, de l'ordre de 80 GPa à 120 GPa. Cette combinaison de propriétés convient bien pour un ressort spiral. L'alliage après les séquences de déformation-traitement thermique présente une texture <110>. En outre, cet alliage niobium-titane selon l'invention se laisse facilement recouvrir de matériau ductile ou cuivre, ce qui facilite grandement sa déformation par tréfilage.By a suitable combination of deformation and heat treatment sequences, it is possible to obtain a very fine two-phase lamellar microstructure, in particular nanometric, comprising or composed of beta niobium and alpha titanium. This alloy combines a very high elastic limit, greater than at least 500 MPa, and a very low modulus of elasticity, of the order of 80 GPa to 120 GPa. This combination of properties works well for a spiral spring. The alloy after the deformation-heat treatment sequences exhibits a <110> texture. In addition, this niobium-titanium alloy according to the invention can easily be covered with ductile material or copper, which greatly facilitates its deformation by drawing.

Un alliage de type binaire comportant du niobium et du titane, du type sélectionné ci-dessus pour la mise en œuvre de l'invention, présente également un effet similaire à celui de l' « Elinvar », avec un coefficient thermo-élastique pratiquement nul dans la plage de températures d'utilisation usuelle de montres, et apte à la fabrication de spiraux auto-compensateurs.A binary type alloy comprising niobium and titanium, of the type selected above for the implementation of the invention, also exhibits an effect similar to that of "Elinvar", with a thermoelastic coefficient practically zero. within the temperature range of usual use of watches, and suitable for the manufacture of self-compensating balance springs.

Plus précisément, si on compare à la figure 2, l'évolution du module de Young (E(T)/E20°C) en fonction de la température pour du Nb pur et un alliage de Nb-Ti selon l'invention avec 30% en poids de Ti, on observe que les deux courbes sont en S avec pour différence notable que la présence de Ti permet de réduire fortement l'écart entre le minimum et le maximum de la courbe selon aussi bien l'axe des abscisses que l'axe des ordonnées. Plus précisément, la présence de Ti dans l'alliage et le procédé de fabrication selon l'invention tentent à lisser la courbe via la diminution du maximum de la courbe. Cet effet positif sur la réduction du maximum avec l'alliage selon l'invention est attribué à un ensemble de facteurs qui sont :

  • la texture cristallographique de l'alliage qui est influencée par le taux de réduction depuis la trempe bêta,
  • la densité de dislocations ajustée via les traitements thermiques qui induisent des phénomènes de restauration, voire de recristallisation,
  • la concentration en interstitiels qui vont interagir avec les dislocations,
  • le pourcentage de Ti en phase alpha
  • la densité de précipités dans l'alliage (nombre de précipités Ti en phase alpha par unité de volume) .
More precisely, if we compare to the figure 2 , the change in Young's modulus (E (T) / E 20 ° C ) as a function of temperature for pure Nb and an Nb-Ti alloy according to the invention with 30% by weight of Ti, it is observed that the two curves are in S with the notable difference that the presence of Ti makes it possible to greatly reduce the difference between the minimum and the maximum of the curve along both the x-axis and the y-axis. More precisely, the presence of Ti in the alloy and the manufacturing method according to the invention attempt to smooth the curve by reducing the maximum of the curve. This positive effect on the reduction of the maximum with the alloy according to the invention is attributed to a set of factors which are:
  • the crystallographic texture of the alloy which is influenced by the rate of reduction since the beta quenching,
  • the dislocation density adjusted via heat treatments which induce restoration or even recrystallization phenomena,
  • the concentration of interstitials that will interact with the dislocations,
  • the percentage of Ti in the alpha phase
  • the density of precipitates in the alloy (number of Ti precipitates in alpha phase per unit volume).

Claims (18)

Ressort spiral (1) destiné à équiper un balancier d'un mouvement d'horlogerie, caractérisé en ce que le ressort spiral (1) est réalisé dans un alliage de niobium et de titane constitué en poids de : - niobium : balance à 100% ; - titane avec un pourcentage supérieur ou égal à 1 % et inférieur à 40%, - des traces d'autres éléments choisis parmi O, H, C, Fe, Ta, N, Ni, Si, Cu et/ou Al, chacun desdits éléments étant compris entre 0 et 1600 ppm du total en poids et la somme desdites traces étant inférieure ou égale à 0.3% en poids. Spiral spring (1) intended to equip a balance of a timepiece movement, characterized in that the spiral spring (1) is made of an alloy of niobium and titanium consisting by weight of: - niobium: balance at 100%; - titanium with a percentage greater than or equal to 1% and less than 40%, - traces of other elements chosen from O, H, C, Fe, Ta, N, Ni, Si, Cu and / or Al, each of said elements being between 0 and 1600 ppm of the total by weight and the sum of said traces being less than or equal to 0.3% by weight. Ressort spiral (1) selon la revendication 1, caractérisé en ce que ledit alliage comporte un pourcentage en poids de titane compris entre 5 et 35%.Spiral spring (1) according to Claim 1, characterized in that the said alloy comprises a percentage by weight of titanium of between 5 and 35%. Ressort spiral (1) selon la revendication 1, caractérisé en ce que ledit alliage comporte un pourcentage en poids de titane compris entre 15 et 35%.Spiral spring (1) according to Claim 1, characterized in that the said alloy comprises a percentage by weight of titanium of between 15 and 35%. Ressort spiral (1) selon la revendication 1, caractérisé en ce que ledit alliage comporte un pourcentage en poids de titane compris entre 27 et 33%.Spiral spring (1) according to Claim 1, characterized in that the said alloy comprises a percentage by weight of titanium of between 27 and 33%. Ressort spiral (1) selon l'une des revendications précédentes, caractérisé en ce qu'il a une microstructure bi-phasée comportant du niobium en phase bêta et du titane en phase alpha.Spiral spring (1) according to one of the preceding claims, characterized in that it has a two-phase microstructure comprising niobium in the beta phase and titanium in the alpha phase. Ressort spiral (1) selon l'une des revendications précédentes, caractérisé en ce qu'il a une limite élastique supérieure ou égale à 500 MPa, et un module d'élasticité inférieur ou égal à 120 GPa, de préférence inférieur ou égal à 110 GPa.Spiral spring (1) according to one of the preceding claims, characterized in that it has an elastic limit greater than or equal to 500 MPa, and a modulus of elasticity less than or equal to 120 GPa, preferably less than or equal to 110 GPa. Procédé de fabrication d'un ressort spiral (1) destiné à équiper un balancier d'un mouvement d'horlogerie, caractérisé en ce qu'il comprend successivement : - une étape d'élaboration d'une ébauche dans un alliage de niobium et de titane constitué en poids de : - niobium : balance à 100% ; - titane avec un pourcentage supérieur ou égal à 1% et inférieur à 40%, - des traces d'autres éléments choisis parmi O, H, C, Fe, Ta, N, Ni, Si, Cu et/ou Al, chacun desdits éléments étant compris entre 0 et 1600 ppm du total en poids et la somme desdites traces étant inférieure ou égale à 0.3% en poids ; - une étape de trempe de type bêta de ladite ébauche, de façon à ce que le titane dudit alliage soit essentiellement sous forme de solution solide avec le niobium en phase bêta, - une étape d'application audit alliage d'une succession de séquences de déformation suivie d'un traitement thermique intermédiaire, - une étape estrapadage pour former le ressort spiral (1), - une étape de traitement thermique final. Method of manufacturing a spiral spring (1) intended to equip a balance of a timepiece movement, characterized in that it comprises successively: - a stage of preparation of a blank in an alloy of niobium and titanium constituted by weight of: - niobium: balance at 100%; - titanium with a percentage greater than or equal to 1% and less than 40%, - traces of other elements chosen from O, H, C, Fe, Ta, N, Ni, Si, Cu and / or Al, each of said elements being between 0 and 1600 ppm of the total by weight and the sum of said traces being less than or equal to 0.3% by weight; a beta-type quenching step of said blank, so that the titanium of said alloy is essentially in the form of a solid solution with the niobium in the beta phase, - a step of applying to said alloy a succession of deformation sequences followed by an intermediate heat treatment, - a stepping step to form the spiral spring (1), - a final heat treatment step. Procédé de fabrication d'un ressort spiral (1) selon la revendication 7, caractérisé en ce que la déformation durant chaque séquence est réalisée par tréfilage et/ou laminage.Method of manufacturing a spiral spring (1) according to Claim 7, characterized in that the deformation during each sequence is carried out by drawing and / or rolling. Procédé de fabrication d'un ressort spiral (1) selon la revendication 8, caractérisé en ce qu'on effectue la déformation de la dernière séquence par laminage à plat.Method of manufacturing a spiral spring (1) according to Claim 8, characterized in that the deformation of the last sequence is carried out by flat rolling. Procédé de fabrication d'un ressort spiral (1) selon l'une des revendications 7 à 9, caractérisé en ce que la déformation de chaque séquence est effectuée avec un taux de déformation donné compris entre 1 et 5, le cumul global des déformations sur l'ensemble de ladite succession de séquences amenant un taux total de déformation compris entre 1 et 14.Method of manufacturing a spiral spring (1) according to one of claims 7 to 9, characterized in that the deformation of each sequence is carried out with a given deformation rate of between 1 and 5, the overall sum of the deformations on the whole of said succession of sequences leading to a total rate of deformation of between 1 and 14. Procédé de fabrication d'un ressort spiral (1) selon l'une des revendications 7 à 10, caractérisé en ce que la trempe de type bêta est un traitement de mise en solution, avec une durée comprise entre 5 minutes et 2 heures à une température comprise entre 700°C et 1000°C, sous vide, suivie d'un refroidissement sous gaz.Method of manufacturing a spiral spring (1) according to one of claims 7 to 10, characterized in that the beta-type quenching is a solution treatment, with a duration of between 5 minutes and 2 hours at a temperature between 700 ° C and 1000 ° C, under vacuum, followed by gas cooling. Procédé de fabrication d'un ressort spiral (1) selon l'une des revendications 7 à 11, caractérisé en ce que la trempe de type bêta est un traitement de mise en solution d'1 heure à 800°C sous vide, suivie d'un refroidissement sous gaz.A method of manufacturing a spiral spring (1) according to one of claims 7 to 11, characterized in that the beta-type quenching is a treatment of dissolving for 1 hour at 800 ° C under vacuum, followed by 'gas cooling. Procédé de fabrication d'un ressort spiral (1) selon l'une des revendications 7 à 12, caractérisé en ce que le traitement thermique final ainsi que le traitement thermique intermédiaire de chaque séquence est un traitement de précipitation du Ti en phase alpha d'une durée comprise entre 1 heure et 200 heures à une température comprise entre 300°C et 700°C.Method of manufacturing a spiral spring (1) according to one of claims 7 to 12, characterized in that the final heat treatment as well as the intermediate heat treatment of each sequence is a treatment of precipitation of Ti in the alpha phase of a period of between 1 hour and 200 hours at a temperature of between 300 ° C and 700 ° C. Procédé de fabrication d'un ressort spiral (1) selon l'une des revendications 7 à 13, caractérisé en ce que le traitement thermique final ainsi que le traitement thermique intermédiaire de chaque séquence est un traitement de précipitation du Ti en phase alpha d'une durée comprise entre 5 heures et 30 heures à une température comprise entre 400°C et 600°C.Method of manufacturing a spiral spring (1) according to one of claims 7 to 13, characterized in that the final heat treatment as well as the intermediate heat treatment of each sequence is a treatment of precipitation of Ti in the alpha phase of a period of between 5 hours and 30 hours at a temperature between 400 ° C and 600 ° C. Procédé de fabrication d'un ressort spiral (1) selon l'une des revendications 7 à 14, caractérisé en ce que ledit procédé comporte entre une et cinq dites séquences de déformation suivie d'un traitement thermique intermédiaire.A method of manufacturing a spiral spring (1) according to one of claims 7 to 14, characterized in that said method comprises between one and five said deformation sequences followed by an intermediate heat treatment. Procédé de fabrication d'un ressort spiral (1) selon l'une des revendications 7 à 15, caractérisé en ce que la première dite séquence de déformation suivie d'un traitement thermique intermédiaire comporte une première déformation avec au moins 30 % de réduction de section.Method of manufacturing a spiral spring (1) according to one of claims 7 to 15, characterized in that the first said deformation sequence followed by an intermediate heat treatment comprises a first deformation with at least 30% reduction in section. Procédé de fabrication d'un ressort spiral (1) selon la revendication 16, caractérisé en ce que chaque dite séquence de déformation suivie d'un traitement thermique intermédiaire, autre que la première, comporte une déformation entre deux traitements thermiques intermédiaires avec au moins 25 % de réduction de section.Method of manufacturing a spiral spring (1) according to Claim 16, characterized in that each said sequence of deformation followed by an intermediate heat treatment, other than the first, comprises a deformation between two intermediate heat treatments with at least 25 % section reduction. Procédé de fabrication d'un ressort spiral (1) selon l'une des revendications 7 à 17, caractérisé en ce que, après l'étape d'élaboration de l'ébauche en alliage, et avant l'étape d'application d'une succession de séquences, on ajoute à ladite ébauche une couche superficielle de matériau ductile pris parmi le cuivre, le nickel, le cupro-nickel, le cupro-magnanèse, l'or, l'argent, le nickel-phosphore Ni-P et le nickel-bore Ni-B, pour faciliter la mise en forme sous forme de fil et en ce que, avant ou après l'étape d'estrapadage, on débarrasse ledit fil de sa couche dudit matériau ductile par attaque chimique.Method of manufacturing a spiral spring (1) according to one of claims 7 to 17, characterized in that , after the step of producing the alloy blank, and before the step of applying a succession of sequences, a surface layer of ductile material taken from among copper, nickel, cupro-nickel, cupro-magnanes, gold, silver, nickel-phosphorus Ni-P and nickel-boron Ni-B, to facilitate shaping in the form of a wire and in that , before or after the stranding step, said wire is freed from its layer of said ductile material by chemical etching.
EP19198759.3A 2019-09-20 2019-09-20 Hairspring for clock movement Pending EP3796101A1 (en)

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US16/936,682 US20210088971A1 (en) 2019-09-20 2020-07-23 Balance spring for a horological movement
JP2020136578A JP7148577B2 (en) 2019-09-20 2020-08-13 Balance springs for timepiece movements
CN202210710467.XA CN114990402A (en) 2019-09-20 2020-09-18 Balance spring for a timepiece movement
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EP4123393A1 (en) 2021-07-23 2023-01-25 Nivarox-FAR S.A. Hairspring for clock movement

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JP2021051065A (en) 2021-04-01
JP7148577B2 (en) 2022-10-05
CN114990402A (en) 2022-09-02
US20210088971A1 (en) 2021-03-25
CN112538587B (en) 2022-08-16
CN112538587A (en) 2021-03-23

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