EP4057077A1 - Timepiece component made of lead-free brass and manufacturing method thereof - Google Patents
Timepiece component made of lead-free brass and manufacturing method thereof Download PDFInfo
- Publication number
- EP4057077A1 EP4057077A1 EP21161435.9A EP21161435A EP4057077A1 EP 4057077 A1 EP4057077 A1 EP 4057077A1 EP 21161435 A EP21161435 A EP 21161435A EP 4057077 A1 EP4057077 A1 EP 4057077A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- temperature
- hardness
- hours
- heat treatment
- semi
- 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.)
- Withdrawn
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C9/00—Alloys based on copper
- C22C9/04—Alloys based on copper with zinc as the next major constituent
-
- 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
- C22F1/08—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of copper 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
- G04B1/00—Driving mechanisms
- G04B1/10—Driving mechanisms with mainspring
- G04B1/16—Barrels; Arbors; Barrel axles
-
- 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
- G04B29/00—Frameworks
- G04B29/02—Plates; Bridges; Cocks
- G04B29/022—Bridges
-
- 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
- G04B29/00—Frameworks
- G04B29/02—Plates; Bridges; Cocks
- G04B29/027—Materials and manufacturing
Definitions
- the invention relates to a timepiece component made of lead-free brass and its method of manufacture.
- the CuZn42 alloy is a brass with a very low lead content (less than 0.2% by weight) nevertheless suitable for machining thanks to its two-phase ⁇ + ⁇ structure. Its lead-free composition makes it a material of choice for watchmaking applications. However, the development of this material for a watch component is not currently suitable for obtaining the extreme precision in terms of dimensioning and flatness required for such a component.
- the material in the semi-finished state after a shaping step by deformation presents internal stresses which affect the dimensioning of the part during its machining. It is known to carry out stress relief before the machining step so as to relax these internal stresses and therefore to avoid unwanted deformations during machining.
- the stress relief tempering temperature ranges are optimized for Pb brasses with typically a tempering temperature between 250°C and 300°C. Heat treatment in this temperature range allows to relax the stresses while maintaining a similar hardness after tempering the material. It turns out that these parameters are not suitable for brasses without Pb, an excessive drop in hardness being observed at these temperature ranges.
- the object of the invention is to overcome the aforementioned drawbacks by proposing a new process for manufacturing a watch component made of lead-free brass with a step for relieving internal stresses optimized for the CuZn42 alloy.
- this alloy has the following advantages. It has a higher zinc content with the corollary of a higher ⁇ phase content, typically 30%, which improves machinability. Then, the CuZn42 alloy has a higher work hardening potential than leaded brass, which allows during the shaping step by deformation to reach a hardness greater than 200HV.
- the manufacturing process and in particular the stress relief tempering step, has been optimized to reduce the loss of hardness after tempering to a difference of less than or equal to 30 HV2, or even 20 HV2, or even 10 HV2.
- the target hardness after tempering is between 120 and 190 HV2, preferably between 150 and 190 HV2, more preferably between 170 and 190 HV2, and even more preferably between 180 and 190 HV2.
- a greater or lesser loss of hardness after tempering is authorized.
- the invention also relates to the timepiece component resulting from the manufacturing process. It has the characteristic of having a hardness of between 120 and 190 HV2, preferably between 150 and 190 HV2, more preferably between 170 and 190 HV2, even more preferably between 180 and 190 HV2 and of being relaxed. Watch components, in particular those of the movement, made in this relaxed alloy are characterized by minimal deformation, typically a few tenths of a micron maximum, after machining by subtraction of material. This condition ensures flatness and movement between the different mechanical levels of the movement.
- the difference in position of the characteristic machining (bores, recesses, etc.) of each assembly level is minimal, which makes it possible to ensure the adjustment of the components mechanically connecting the levels to each other and, in particular , to guarantee the co-axiality of the axes which are retained by the bridges.
- a methodology has been developed to differentiate between a watch component that has been subjected to optimized stress relief according to the invention and a watch component that has not been relaxed with the process. according to the invention. It consists of measuring the dynamic shear modulus M 100 on the final product and measuring it again after heat treatment at 200°C for 1 hour, the delta M 100 ( ⁇ M 100 ) before and after heat treatment being a measurement of the stress relaxation state within the material. A small change in the dynamic shear modulus indicates that the heat treatment no longer significantly affects the mechanisms involved during stress relaxation. Typically, a delta M 100 of less than 0.4 GPa makes it possible to ensure that the watch component placed on the market has indeed been subjected to stress relief tempering according to the method of the invention.
- the figure 1 represents a watch component according to the invention produced in CuZn42 brass.
- the figure 2A and 2B comparatively represent the evolution of the hardness as a function of the tempering temperature for respectively a brass with Pb CuZn38Pb2 and the brass without Pb CuZn42 used in the context of the invention.
- the picture 3 shows the evolution of the shear modulus at 100°CM 100 as a function of the holding time at 180°C (T1) and at 200°C (T2) for CuZn42 with a work-hardened hardness of 175 HV2.
- the figure 4 shows the evolution of the shear modulus at 100°CM 100 as a function of the holding time at 180°C for CuZn42 brasses having different hardnesses in the work-hardened state as well as a result at 220°C for 1 hour for a CuZn42 brass having a hardness in the work-worked state of 210 HV2.
- the figure 5 represents the geometry of the strain gauge used to determine the state of relaxation of CuZn42 brass.
- the AA axis is parallel to the rolling direction.
- the present invention relates to the process for manufacturing a watch component made from a Pb-free brass and more specifically from the CuZn42 alloy.
- the CuZn42 alloy according to the ASTM C28500 standard has the following composition by weight: Cu between 57 and 59% (limits included), Pb ⁇ 0.2%, Sn ⁇ 0.3%, Fe ⁇ 0.3%, Ni ⁇ 0.2%, Al ⁇ 0.05 %, other elements ⁇ 0.2%, Zn balance 100%. It is specified here that adaptations at the level of the composition, and in particular for the elements Sn, Fe, Ni and In, are possible and deviate very significantly from the ASTM C28500 standard. For example, the contents by weight of Fe, Sn, Ni and In could go up to 0.5, 0.5, 0.5 and 0.3% respectively. Such adaptations are considered to cover the CuZn42 alloy.
- the manufacturing method according to the invention is suitable for all horological components and in particular movement components. However, it is more specifically suitable for components with high precision requirements in terms of dimensions such as the plate, the bridges ( fig.1 ), blank, barrel, barrel cover, barrel drum, etc.
- the drum and the cover have a thin wall for a large external diameter with typically an external diameter / wall thickness ratio of 45, the realization of thin walls without residual deformation being particularly critical during machining. . More generally, the outside diameter/thickness ratio of the wall is between 20 and 70.
- the CuZn42 brass watch component has a hardness HV2 of between 120 and 190, preferably between 150 and 190, more preferably between 170 and 190, even more preferably between 180 and 190, the Vickers hardness being measured for example on a semi-automatic Shimadzu HMV-G20 machine with a 2kg load.
- the detection of the size of the imprints is done manually with the aforementioned average values determined on the basis of at least 3 measurements.
- the manufacturing process is therefore optimized to obtain this target hardness on the final product while relaxing the stresses during stress relief to avoid unwanted deformations during machining.
- the semi-finished part made available is typically a rolled strip or an extruded bar. It may already have been cut out, optionally thickening, after shaping by deformation, for example in the form of trays or washers and optionally pre-machined, for example by trimming.
- the method can comprise an additional step of cutting and optionally of setting to thickness and of pre-machining before the stress-relieving heat treatment. This cutting step is carried out on the hardened material, ie. before stress relief, so as to have a hard material, which facilitates this cutting.
- the semi-finished part can be machined to obtain the final shape of the watch component without residual deformation. Machining is carried out by milling, drilling and/or tapping or any other machining operation by chip removal. The machining may be followed by a finishing treatment, such as polishing and/or engraving for decoration.
- stress relief tempering is carried out in a range of temperatures between 170°C and 230°C.
- the tempering is carried out in a range of temperatures comprised between 175° C. and 195° C. for a time comprised between 1 hour and 4 hours.
- Stress relieving is intended to relieve internal stresses without significantly affecting hardness.
- the physical mechanisms involved during stress relief tempering have as their main function the local reorganization of the defects generated during shaping.
- the supply of thermal energy during tempering mainly enables the activation of the diffusion of defects which, thanks to their mobility, can be annihilated or reconfigured in such a way as to minimize the local energy.
- Atomic scale defects are mainly linear grain defects (dislocations), vacancies, interstitials, substitutionals or other point defects.
- dislocations mainly linear grain defects (dislocations), vacancies, interstitials, substitutionals or other point defects.
- vacancies vacancies
- interstitials substitutionals or other point defects.
- recrystallization a large-scale structural modification
- the loss of hardness between before and after stress relief tempering is less than or equal to 30 HV2, preferably less than or equal to 20 HV2, more preferably less than or equal to 10 HV2.
- the authorized hardness delta is determined on the basis of the target hardness on the final product and the initial hardness modulated according to the composition of the alloy and the rate of deformation applied during shaping.
- a delta of 20 or 30 HV2 is authorized to reach the hardness target around 180 HV2.
- a higher tempering temperature may be recommended when the initial hardness is high.
- the stress relief heat treatment can be carried out at a temperature of between 175° and 195° C. for a time of between 30 minutes and 5 hours, preferably between 1 and 4 hours.
- the stress relief heat treatment can be carried out at a temperature of between 195°C and 220°C for a time of between 30 minutes and 5 hours, from preferably between 1 and 4 hours.
- the choice of a tempering temperature greater than or equal to 250°C, as recommended for leaded brasses, causes a significant loss of hardness.
- the recommended temperature range is between 170°C and 230°C to avoid a drastic drop in hardness.
- Mechanical spectroscopy is a method of physical analysis in which a torsion pendulum, which incorporates the test piece made with the material to be analyzed, is subjected to forced oscillations in a vacuum chamber whose temperature is controlled.
- the apparatus measures, as a function of the temperature, the amplitude and the phase of deformation of the specimen during heating/cooling cycles.
- the amplitude and the phase shift of the deformation with the forced excitation are related to the viscoelastic properties of the material, ie to the way in which the internal defects are reorganized to accommodate the variation of stresses to which the specimen is subjected.
- the dynamic shear modulus M is an indicator of the state of relaxation of the material ( W. Benoit, “Dislocation-Lattice interactions,” Materials Science Forum, Vols. 366-368, pp. 158-177, 2001 ) ( J. Lauzier, J. Hillaire, G. Gremaud and W. Benoit, "Lubrication agents of dislocation motion at very low temperature in cold worked aluminium,” J. Phys. : Condens. Mater., vol. 2, p. 9247, 1990 ).
- This indicator makes it possible to follow the kinetics of the evolution of the expansion according to the temperature and the duration of tempering.
- the gain recorded on the value of M 100 becomes negligible beyond 180 minutes.
- the maximum ⁇ M 100 is 1.2 GPa at 180°C and 1.5 GPa at 200°C, with therefore more effective expansion with increasing temperature.
- As regards the hardness after 180 minutes at 180°C, it is 170 HV2, ie only a loss of 5 HV2. By increasing the tempering time to 5 hours at 180° C., no additional drop in hardness is observed. After 30 minutes at 200°C, it is 166 HV2, i.e. only a loss of 9 HV2. After 180 minutes at 200°C, it is 164 HV2, i.e. only a loss of 11 HV2.
- an alternative to the maximization of ⁇ M 100 is the minimization of the deformation of a gauge specifically designed to represent watchmaking machining of bridges or any other watchmaking component machined in a semi-finished part. finished in rolled strip or bar form.
- the strain gauge has a geometry chosen so as to deform, preferably by buckling, when it detaches from the matrix in which it is machined. Its preferably circular geometry is characterized in that the thickness/diameter ratio is greater than 10, preferably greater than 100 and that it is easily detachable from the matrix in which it is machined.
- the design of the strain gauge is based on the principle of buckling which means that when the residual tensions in the membrane constituting its bottom are greater than a critical value, the gauge will deform into flaming during its detachment and reaching a form of equilibrium characteristic of the state of the residual stresses present in the material constituting the membrane of the gauge. In order to guarantee a good relaxation of the brass, it is a question of minimizing the buckling of the gauge during its detachment. By way of example, the measurements were taken with a gauge whose geometry is shown in figure 5 .
- the gauge consists of a low cylinder with an internal diameter of 32 mm comprising a very thin bottom of 0.3 mm (thickness/diameter ratio equal to about 100) in which six hollows of diameter 4 mm and depth 0.15 mm are machined.
- the gauge is machined from a tray extracted by stamping or by milling in the rolled strip with a thickness of one to a few millimeters. Whatever the initial thickness of the strip, the bottom thickness is fixed at 0.3 mm. After machining the cylinder and the recesses, the gauge is then partially trimmed to remain held by three clips to the tray, so as to be easily detachable in a later stage.
- the thin bottom is designed to deform noticeably in the presence of residual stresses.
- the approach applied in this study consists in qualifying the relaxation of the material by the quantitative measurement of the deformations of the gauge during detachment. These are deduced from the values of two indicators, measured by qualifying the topography of the bottom of the part a first time after machining the part (gauge attached to the tray) and a second time after detachment by breaking the three fasteners ( detached gauge).
- the maximum strain i.e. the relative flatness observed on the bottom is an indicator of the relaxation of the material.
- the measurements are carried out by optical microscopy, a positioning dedicated to the measuring devices allowing to ensure the precise and repeatable positioning of the gauge, whether it is attached or detached.
- the flatness is evaluated from the optical measurement of the distribution of the heights of the bottom of the gauge carried out by confocal microscopy in white light (FTR Microprof instrument with dedicated mounting ensuring the reproducibility of the positioning of the gauge).
- the value of the height z is measured in steps of 0.2 mm in x and in y.
- the topography of the internal surface of the bottom is established by freeing itself from the effects of the residual roughness by averaging the value of z calculated on a surface of 1 mm 2 (average over approximately 25 points).
- the possible overall tilt error of the gauge in the layout is reduced by subtracting the mean plane of the part. We thus obtain the distribution of the values of the residuals z i in the mean plane.
- the flatness P is defined as the deviation separating two parallel planes containing the entire surface, quantified by the value z max - z min .
- the relative deformation of the gauge is evaluated between the "attached" state and the "detached" state, by point-by-point subtraction of the two topographies z a (x;y) and z d (x;y) .
- the maximum deformation (relative flatness) is obtained by taking the maximum value of the height difference, ie max
- the measurements were carried out on a CuZn42 brass having a work-hardened hardness of 173 HV2. In the hardened state, the maximum deformation is 7.1 ⁇ m. After stress relief tempering at 180°C for 3 hours, the maximum strain drops to 2.2 ⁇ m. On a CuZn42 brass having a hardness in the work-hardened state of 210 HV2, subjected to a stress-relieving treatment at 220°C for 1 hour, the maximum deformation is 2.2 ⁇ m.
- the maximum deformation is 2.7 ⁇ m whereas it is 4.7 ⁇ m in the work-hardened state .
- a maximum deformation less than or equal to 3.5 ⁇ m and preferably 3 ⁇ m is also an indicator of the state of relaxation of the material.
- the present invention also relates to the watch component made of this alloy and obtained at the end of the process described above.
- this component is characterized by the choice of CuZn42 brass material, by its hardness with values between 120 and 190 HV2, preferably between 150 and 190 HV2, more preferably between 170 and 190 HV2, even more preferably between 180 and 190 HV2. It is also characterized by its relaxed state as opposed to the hardened state after it has been shaped by deformation. To characterize this state on the final product, the following procedure is used.
- the dynamic shear modulus M 100 is measured on a sample taken from the watch component.
- the sample can be of planar geometry (blade) or cylindrical (wire), the geometry of the sample having no impact on the measured value.
- the sample taken from this same component is characterized in a mechanical spectroscopy test bench chosen according to the geometry of the sample.
- the variation of the dynamic shear modulus ⁇ M 100 between the initial state before tempering and that after tempering is noted after the application of the temperature scanning protocol 1) described above.
- the holding time is one hour at a temperature of 200°C. It can be concluded that the component is in the relaxed state, and has therefore been manufactured with the process according to the invention, if the ⁇ M 100 is less than 0.4 GPa, or even 0.2 GPa, which corresponds to variations in M 100 in the "plateau" zone of the figure 3 and 4 after the sudden increase of M 100 during the first hour.
- a means of differentiating a timepiece component relaxed according to the manufacturing method of the invention and a timepiece component that is not relaxed can also consist in measuring the maximum deformation as described above on a sample machined in the timepiece component, with a value which must be less than or equal to the threshold value determined, for the chosen geometry, on reference samples machined in relaxed material.
- the specimen is designed so that it deforms by buckling when released after machining.
Abstract
L'invention concerne un procédé de fabrication d'un composant horloger (1) en laiton CuZn42 avec une dureté comprise entre 120 et 190 HV2, ledit procédé comprenant les étapes suivantes :
- Mise à disposition d'une pièce semi-finie ayant été mise en forme par déformation, ladite pièce semi-finie ayant une dureté comprise entre 130 et 220 HV2 et étant réalisée dans un matériau en laiton CuZn42,
- Traitement thermique de détente de ladite pièce semi-finie à une température comprise entre 170 et 230°C avec un temps de maintien à ladite température compris entre 20 minutes et 10 heures, de préférence entre 30 minutes et 5 heures, plus préférentiellement entre 1 heure et 4 heures,
- Usinage et finition de ladite pièce semi-finie pour réaliser le composant horloger (1).The invention relates to a method for manufacturing a watch component (1) in CuZn42 brass with a hardness of between 120 and 190 HV2, said method comprising the following steps:
- Provision of a semi-finished part having been shaped by deformation, said semi-finished part having a hardness of between 130 and 220 HV2 and being made of a CuZn42 brass material,
- Expansion heat treatment of said semi-finished part at a temperature of between 170 and 230° C. with a holding time at said temperature of between 20 minutes and 10 hours, preferably between 30 minutes and 5 hours, more preferably between 1 o'clock and 4 o'clock,
- Machining and finishing of said semi-finished part to produce the watch component (1).
L'invention se rapporte également au composant horloger réalisé dans un laiton CuZn42. The invention also relates to the watch component made of a CuZn42 brass.
Description
L'invention concerne un composant horloger réalisé dans un laiton sans plomb et son procédé de fabrication.The invention relates to a timepiece component made of lead-free brass and its method of manufacture.
Dans le domaine horloger, de nombreux composants sont réalisés dans du laiton traditionnel contenant du plomb tel que l'alliage CuZn38Pb2. Cet élément dont la teneur dans le laiton est de 2 à 3% permet une meilleure usinabilité. Cependant, le plomb présente une certaine toxicité, même à basse concentration. L'élimination du plomb dans les matériaux devient donc aujourd'hui une nécessité.In the watchmaking field, many components are made from traditional brass containing lead such as the CuZn38Pb2 alloy. This element whose content in brass is 2 to 3% allows better machinability. However, lead has some toxicity, even at low concentrations. The elimination of lead in materials therefore becomes a necessity today.
L'alliage CuZn42 est un laiton avec une très faible teneur en plomb (inférieure à 0.2% en poids) néanmoins apte à l'usinage grâce à sa structure biphasée α+β. Sa composition sans plomb en fait un matériau de choix pour une application horlogère. Cependant, l'élaboration de ce matériau pour un composant horloger n'est à ce jour pas adaptée pour obtenir l'extrême précision en termes de dimensionnement et planéité requise pour un tel composant.The CuZn42 alloy is a brass with a very low lead content (less than 0.2% by weight) nevertheless suitable for machining thanks to its two-phase α+β structure. Its lead-free composition makes it a material of choice for watchmaking applications. However, the development of this material for a watch component is not currently suitable for obtaining the extreme precision in terms of dimensioning and flatness required for such a component.
En effet, le matériau à l'état semi-fini après une étape de mise en forme par déformation (laminage, extrusion, etc.) présente des contraintes internes qui affectent le dimensionnement de la pièce lors de son usinage. Il est connu de réaliser un revenu de détente avant l'étape d'usinage de manière à relaxer ces contraintes internes et dès lors à éviter les déformations non désirées lors de l'usinage. A ce jour, les gammes de températures du revenu de détente sont optimisées pour les laitons au Pb avec typiquement une température de revenu comprise entre 250°C et 300°C. Le traitement thermique dans cette gamme de températures permet de relaxer les contraintes tout en maintenant une dureté semblable après le revenu du matériau. Il s'avère que ces paramètres ne sont pas adaptés pour les laitons sans Pb, une baisse trop importante de la dureté étant observée à ces gammes de températures.Indeed, the material in the semi-finished state after a shaping step by deformation (rolling, extrusion, etc.) presents internal stresses which affect the dimensioning of the part during its machining. It is known to carry out stress relief before the machining step so as to relax these internal stresses and therefore to avoid unwanted deformations during machining. To date, the stress relief tempering temperature ranges are optimized for Pb brasses with typically a tempering temperature between 250°C and 300°C. Heat treatment in this temperature range allows to relax the stresses while maintaining a similar hardness after tempering the material. It turns out that these parameters are not suitable for brasses without Pb, an excessive drop in hardness being observed at these temperature ranges.
Il convient dès lors de développer un procédé de fabrication pour les laitons sans Pb adapté aux exigences des composants horlogers.It is therefore necessary to develop a manufacturing process for Pb-free brass adapted to the requirements of watch components.
L'invention a pour but de pallier les inconvénients précités en proposant un nouveau procédé de fabrication d'un composant horloger réalisé dans du laiton sans plomb avec une étape de relaxation des contraintes internes optimisée pour l'alliage CuZn42. Outre son absence de plomb, cet alliage présente les avantages suivants. Il a une teneur en zinc plus élevée avec pour corollaire un taux de phase β plus élevé, typiquement de 30%, ce qui permet d'améliorer l'usinabilité. Ensuite, l'alliage CuZn42 a un potentiel d'écrouissage plus élevé que le laiton au plomb, ce qui permet lors de l'étape de mise en forme par déformation d'atteindre une dureté supérieure à 200HV. Ces avantages en font un bon candidat pour remplacer le laiton au plomb dans les composants horlogers.The object of the invention is to overcome the aforementioned drawbacks by proposing a new process for manufacturing a watch component made of lead-free brass with a step for relieving internal stresses optimized for the CuZn42 alloy. In addition to its absence of lead, this alloy has the following advantages. It has a higher zinc content with the corollary of a higher β phase content, typically 30%, which improves machinability. Then, the CuZn42 alloy has a higher work hardening potential than leaded brass, which allows during the shaping step by deformation to reach a hardness greater than 200HV. These advantages make it a good candidate to replace leaded brass in watch components.
Selon l'invention, le procédé de fabrication, et en particulier l'étape de revenu de détente, a été optimisé pour réduire la perte de dureté après revenu à une différence inférieure ou égale à 30 HV2, voire à 20 HV2, voire même à 10 HV2. La dureté cible après revenu est comprise entre 120 et 190 HV2, de préférence entre 150 et 190 HV2, plus préférentiellement entre 170 et 190 HV2, et encore plus préférentiellement entre 180 et 190 HV2. En fonction de la dureté du matériau avant revenu qui est variable selon le taux d'écrouissage, une perte de dureté plus ou moins grande après revenu est autorisée.According to the invention, the manufacturing process, and in particular the stress relief tempering step, has been optimized to reduce the loss of hardness after tempering to a difference of less than or equal to 30 HV2, or even 20 HV2, or even 10 HV2. The target hardness after tempering is between 120 and 190 HV2, preferably between 150 and 190 HV2, more preferably between 170 and 190 HV2, and even more preferably between 180 and 190 HV2. Depending on the hardness of the material before tempering, which varies according to the strain hardening rate, a greater or lesser loss of hardness after tempering is authorized.
Plus précisément, l'invention se rapporte au procédé de fabrication d'un composant horloger en laiton CuZn42 ayant une dureté comprise entre 120 et 190 HV2, ledit procédé comprenant les étapes suivantes :
- Mise à disposition d'une pièce semi-finie ayant été mise en forme par déformation, ladite pièce semi-finie étant réalisée dans un matériau en laiton CuZn42 et ayant une dureté comprise entre 130 et 220 HV2, de préférence entre 160 et 220 HV2, plus préférentiellement entre 170 et 220 HV2, et encore plus préférentiellement entre 180 et 220 HV2,
- Traitement thermique de détente de ladite pièce semi-finie à une température comprise entre 170 et 230°C avec un temps de maintien à ladite température compris entre 20 minutes et 10 heures, de préférence entre 30 minutes et 5 heures, plus préférentiellement entre 1 heure et 4 heures,
- Usinage et finition de ladite pièce semi-finie pour réaliser le composant horloger.
- Provision of a semi-finished part having been shaped by deformation, said semi-finished part being made of a CuZn42 brass material and having a hardness of between 130 and 220 HV2, preferably between 160 and 220 HV2, more preferentially between 170 and 220 HV2, and even more preferentially between 180 and 220 HV2,
- Expansion heat treatment of said semi-finished part at a temperature of between 170 and 230°C with a holding time at said temperature of between 20 minutes and 10 hours, preferably between 30 minutes and 5 hours, more preferably between 1 hour and 4 o'clock,
- Machining and finishing of said semi-finished part to produce the watch component.
L'invention porte également sur le composant horloger issu du procédé de fabrication. Il présente pour caractéristique d'avoir une dureté comprise entre 120 et 190 HV2, de préférence entre 150 et 190 HV2, plus préférentiellement entre 170 et 190 HV2, encore plus préférentiellement entre 180 et 190 HV2 et d'être détendu. Les composants horlogers, en particulier ceux du mouvement, réalisés dans cet alliage détendu sont caractérisés par une déformation minimale, typiquement quelques dixièmes de microns maximum, après usinage par soustraction de matière. Cette condition assure la planéité et les ébats entre les différents niveaux mécaniques du mouvement. De même, l'écart de position des usinages caractéristiques (alésages, creusures, ...) de chaque niveau d'assemblage est minimal, ce qui permet d'assurer l'ajustement des composants reliant mécaniquement les niveaux entre eux et, en particulier, de garantir la co-axialité des axes qui sont retenus par les ponts.The invention also relates to the timepiece component resulting from the manufacturing process. It has the characteristic of having a hardness of between 120 and 190 HV2, preferably between 150 and 190 HV2, more preferably between 170 and 190 HV2, even more preferably between 180 and 190 HV2 and of being relaxed. Watch components, in particular those of the movement, made in this relaxed alloy are characterized by minimal deformation, typically a few tenths of a micron maximum, after machining by subtraction of material. This condition ensures flatness and movement between the different mechanical levels of the movement. Similarly, the difference in position of the characteristic machining (bores, recesses, etc.) of each assembly level is minimal, which makes it possible to ensure the adjustment of the components mechanically connecting the levels to each other and, in particular , to guarantee the co-axiality of the axes which are retained by the bridges.
Pour caractériser cet état de détente du matériau sur le produit final, une méthodologie a été mise au point pour différencier un composant horloger ayant été soumis au revenu de détente optimisé selon l'invention et un composant horloger n'ayant pas été détendu avec le procédé selon l'invention. Elle consiste à mesurer le module de cisaillement dynamique M100 sur le produit final et à le mesurer à nouveau après un traitement thermique à 200°C pendant 1 heure, le delta M100 (ΔM100) avant et après traitement thermique étant une mesure de l'état de relaxation des contraintes au sein du matériau. Une faible variation du module de cisaillement dynamique indique que le traitement thermique n'affecte plus significativement les mécanismes en jeu lors de la relaxation des contraintes. Typiquement, un delta M100 inférieur à 0.4 GPa permet de s'assurer que le composant horloger mis sur le marché a bien été soumis à un revenu de détente selon le procédé de l'invention.To characterize this state of relaxation of the material on the final product, a methodology has been developed to differentiate between a watch component that has been subjected to optimized stress relief according to the invention and a watch component that has not been relaxed with the process. according to the invention. It consists of measuring the dynamic shear modulus M 100 on the final product and measuring it again after heat treatment at 200°C for 1 hour, the delta M 100 (ΔM 100 ) before and after heat treatment being a measurement of the stress relaxation state within the material. A small change in the dynamic shear modulus indicates that the heat treatment no longer significantly affects the mechanisms involved during stress relaxation. Typically, a delta M 100 of less than 0.4 GPa makes it possible to ensure that the watch component placed on the market has indeed been subjected to stress relief tempering according to the method of the invention.
D'autres caractéristiques et avantages de la présente invention apparaîtront dans la description suivante de modes de réalisation préférés, présentés à titre d'exemple non limitatif en référence aux dessins annexés.Other characteristics and advantages of the present invention will appear in the following description of preferred embodiments, presented by way of non-limiting example with reference to the appended drawings.
La
Les
La
La
La
La présente invention se rapporte au procédé de fabrication d'un composant horloger réalisé dans un laiton sans Pb et plus spécifiquement dans l'alliage CuZn42. L'alliage CuZn42 selon la norme ASTM C28500 a la composition suivante en poids : Cu entre 57 et 59% (bornes incluses), Pb ≤ 0.2%, Sn ≤ 0.3%, Fe ≤ 0.3%, Ni ≤ 0.2%, Al ≤ 0.05%, autres éléments ≤ 0.2%, Zn balance à 100%. Il est précisé ici que des adaptations au niveau de la composition, et en particulier pour les éléments Sn, Fe, Ni et In, sont possibles et s'écartent très sensiblement de la norme ASTM C28500. Par exemple, les teneurs en poids en Fe, Sn, Ni et In pourraient monter jusqu'à respectivement 0.5, 0.5, 0.5 et 0.3%. On considère que de telles adaptations couvrent l'alliage CuZn42.The present invention relates to the process for manufacturing a watch component made from a Pb-free brass and more specifically from the CuZn42 alloy. The CuZn42 alloy according to the ASTM C28500 standard has the following composition by weight: Cu between 57 and 59% (limits included), Pb ≤ 0.2%, Sn ≤ 0.3%, Fe ≤ 0.3%, Ni ≤ 0.2%, Al ≤ 0.05 %, other elements ≤ 0.2%,
Le procédé de fabrication selon l'invention est adapté pour tous les composants horlogers et en particulier les composants du mouvement. Il est cependant plus spécifiquement adapté pour des composants présentant des exigences de précision importantes en termes de dimensions tels que la platine, les ponts (
Selon l'invention, le composant horloger en laiton CuZn42 a une dureté HV2 comprise entre 120 et 190, de préférence entre 150 et 190, plus préférentiellement entre 170 et 190, encore plus préférentiellement entre 180 et 190, la dureté Vickers étant mesurée par exemple sur une machine semi-automatique Shimadzu HMV-G20 avec une charge de 2kg. La détection de la taille des empreintes est faite manuellement avec les valeurs moyennes précitées déterminées sur la base d'au moins 3 mesures. Le procédé de fabrication est dès lors optimisé pour obtenir sur le produit final cette dureté cible tout en relaxant les contraintes lors du revenu de détente pour éviter les déformations non voulues lors de l'usinage.According to the invention, the CuZn42 brass watch component has a hardness HV2 of between 120 and 190, preferably between 150 and 190, more preferably between 170 and 190, even more preferably between 180 and 190, the Vickers hardness being measured for example on a semi-automatic Shimadzu HMV-G20 machine with a 2kg load. The detection of the size of the imprints is done manually with the aforementioned average values determined on the basis of at least 3 measurements. The manufacturing process is therefore optimized to obtain this target hardness on the final product while relaxing the stresses during stress relief to avoid unwanted deformations during machining.
Le procédé de fabrication du composant horloger selon l'invention comprend ainsi au moins les étapes suivantes :
- Mise à disposition d'une pièce semi-finie ayant été mise en forme par déformation par laminage, extrusion, etc.; en d'autres mots, mise à disposition d'une pièce semi-finie à l'état écroui. Cette pièce semi-finie a une dureté comprise entre 130 et 220 HV2, de préférence entre 160 et 220 HV2, plus préférentiellement entre 170 et 220 HV2, et encore plus préférentiellement entre 180 et 220 HV2. A composition chimique équivalente, la dureté de la pièce semi-finie peut être modulée en fonction du taux d'écrouissage et donc du taux de déformation appliquée lors de la mise en forme,
- Traitement thermique de ladite pièce semi-finie, aussi dit revenu de détente, dans une gamme de températures comprise entre 170°C et 230°C (bornes comprises), de préférence entre 180°C et 220°C, avec un temps de maintien dans ces gammes de températures compris entre 20 minutes et 10 heures, de préférence entre 30 minutes et 5 heures et plus préférentiellement entre 1 heure et 4 heures,
- Usinage et finition dudit produit pour obtenir le composant horloger.
- Provision of a semi-finished part that has been shaped by deformation by rolling, extrusion, etc.; in other words, provision of a semi-finished part in the hardened state. This semi-finished part has a hardness of between 130 and 220 HV2, preferably between 160 and 220 HV2, more preferably between 170 and 220 HV2, and even more preferably between 180 and 220 HV2. At an equivalent chemical composition, the hardness of the semi-finished part can be modulated according to the work hardening rate and therefore the rate of deformation applied during shaping,
- Heat treatment of said semi-finished part, also called stress relief, in a temperature range between 170°C and 230°C (limits included), preferably between 180°C and 220°C, with a holding time in these temperature ranges between 20 minutes and 10 hours, preferably between 30 minutes and 5 hours and more preferably between 1 hour and 4 hours,
- Machining and finishing of said product to obtain the watch component.
La pièce semi-finie mise à disposition est typiquement une bande laminée ou une barre extrudée. Elle peut déjà avoir été découpée, éventuellement mise à épaisseur, après la mise en forme par déformation, par exemple sous forme de barquettes ou de rondelles et éventuellement préusinée par exemple par détourage. En variante, le procédé peut comporter une étape additionnelle de découpage et optionnellement de mise à épaisseur et de pré-usinage avant le traitement thermique de détente. Cette étape de découpage est réalisée sur la matière écrouie, c.à.d. avant le revenu de détente, de manière à disposer d'une matière dure, ce qui facilite ce découpage.The semi-finished part made available is typically a rolled strip or an extruded bar. It may already have been cut out, optionally thickening, after shaping by deformation, for example in the form of trays or washers and optionally pre-machined, for example by trimming. As a variant, the method can comprise an additional step of cutting and optionally of setting to thickness and of pre-machining before the stress-relieving heat treatment. This cutting step is carried out on the hardened material, ie. before stress relief, so as to have a hard material, which facilitates this cutting.
Après le revenu de détente, la pièce semi-finie peut être usinée pour obtenir la forme finale du composant horloger sans déformation résiduelle. L'usinage est réalisé par fraisage, perçage et/ou taraudage ou tout autre opération d'usinage par enlèvement de copeaux. L'usinage peut être suivi d'un traitement de finition, tel que du polissage et/ou du gravage pour la décoration.After stress relief, the semi-finished part can be machined to obtain the final shape of the watch component without residual deformation. Machining is carried out by milling, drilling and/or tapping or any other machining operation by chip removal. The machining may be followed by a finishing treatment, such as polishing and/or engraving for decoration.
Selon l'invention, le revenu de détente est réalisé dans une gamme de températures comprise entre 170°C et 230°C. Typiquement, le revenu est réalisé dans une gamme de températures comprise entre 175°C et 195°C pendant un temps compris entre 1 heure et 4 heures. Le revenu de détente a pour objet de relaxer les contraintes internes sans affecter significativement la dureté. Plus précisément, les mécanismes physiques en jeu lors du revenu de détente ont pour fonction principale la réorganisation locale des défauts engendrés au cours de la mise en forme. L'apport d'énergie thermique lors du revenu permet principalement l'activation de la diffusion des défauts qui, grâce à leur mobilité, peuvent s'annihiler ou se reconfigurer de manière à minimiser l'énergie locale. Les défauts à l'échelle atomique sont principalement des défauts linéaires dans les grains (dislocations), lacunes, interstitiels, substitutionnels ou d'autres défauts ponctuels. Afin de maintenir le niveau de dureté, il faut éviter, au cours de la détente, d'activer une modification structurelle à grande échelle telle que la recristallisation, qui modifie profondément l'état métallurgique de la matièreAccording to the invention, stress relief tempering is carried out in a range of temperatures between 170°C and 230°C. Typically, the tempering is carried out in a range of temperatures comprised between 175° C. and 195° C. for a time comprised between 1 hour and 4 hours. Stress relieving is intended to relieve internal stresses without significantly affecting hardness. More precisely, the physical mechanisms involved during stress relief tempering have as their main function the local reorganization of the defects generated during shaping. The supply of thermal energy during tempering mainly enables the activation of the diffusion of defects which, thanks to their mobility, can be annihilated or reconfigured in such a way as to minimize the local energy. Atomic scale defects are mainly linear grain defects (dislocations), vacancies, interstitials, substitutionals or other point defects. In order to maintain the level of hardness, it is necessary to avoid, during the expansion, to activate a large-scale structural modification such as recrystallization, which profoundly modifies the metallurgical state of the material.
(taille de grains, rapport et composition chimique des phases). Selon l'invention, la perte de dureté entre avant et après le revenu de détente est inférieure ou égale à 30 HV2, de préférence inférieure ou égale à 20 HV2, plus préférentiellement inférieure ou égale à 10 HV2. Le delta de dureté autorisé est déterminé sur base de la dureté cible sur le produit final et de la dureté initiale modulée en fonction de la composition de l'alliage et du taux de déformation appliquée lors de la mise en forme. Ainsi, pour une pièce semi-finie avec un taux d'écrouissage plus élevé menant à une dureté de 200 HV2, un delta de 20 ou 30 HV2 est autorisé pour atteindre la cible de dureté autour des 180 HV2. La chute de la dureté augmentant avec la température, une température de revenu plus élevée peut être préconisée lorsque la dureté initiale est élevée. Avantageusement, lorsque la pièce semi-finie a une dureté supérieure ou égale à 130 HV2 et inférieure à 180 HV2, le traitement thermique de détente peut être effectué à une température comprise entre 175° et 195°C pendant un temps compris entre 30 minutes et 5 heures, de préférence entre 1 et 4 heures. Avantageusement, lorsque la pièce semi-finie a une dureté comprise entre 180 et 220 HV2, le traitement thermique de détente peut être effectué à une température comprise entre 195°C et 220°C pendant un temps compris entre 30 minutes et 5 heures, de préférence entre 1 et 4 heures.(grain size, ratio and chemical composition of the phases). According to the invention, the loss of hardness between before and after stress relief tempering is less than or equal to 30 HV2, preferably less than or equal to 20 HV2, more preferably less than or equal to 10 HV2. The authorized hardness delta is determined on the basis of the target hardness on the final product and the initial hardness modulated according to the composition of the alloy and the rate of deformation applied during shaping. Thus, for a semi-finished part with a higher work hardening rate leading to a hardness of 200 HV2, a delta of 20 or 30 HV2 is authorized to reach the hardness target around 180 HV2. As the drop in hardness increases with temperature, a higher tempering temperature may be recommended when the initial hardness is high. Advantageously, when the semi-finished part has a hardness greater than or equal to 130 HV2 and less than 180 HV2, the stress relief heat treatment can be carried out at a temperature of between 175° and 195° C. for a time of between 30 minutes and 5 hours, preferably between 1 and 4 hours. Advantageously, when the semi-finished part has a hardness of between 180 and 220 HV2, the stress relief heat treatment can be carried out at a temperature of between 195°C and 220°C for a time of between 30 minutes and 5 hours, from preferably between 1 and 4 hours.
De nombreux essais ont été réalisés pour déterminer la gamme de températures et de temps optimum pour réaliser la détente sans adoucir significativement le matériau. Comme illustré aux
Pour évaluer l'état de détente de la matière pour ces gammes de températures, des mesures ont été réalisées par spectroscopie mécanique. La spectroscopie mécanique est une méthode d'analyse physique dans laquelle un pendule de torsion, qui incorpore l'éprouvette réalisée avec le matériau à analyser, est soumis à des oscillations forcées dans une enceinte à vide dont la température est contrôlée. Pour une excitation donnée, l'appareil mesure en fonction de la température l'amplitude et la phase de déformation de l'éprouvette durant des cycles de chauffe/refroidissement. L'amplitude et le déphasage de la déformation avec l'excitation forcée sont liés aux propriétés viscoélastiques du matériau, soit à la façon dont les défauts internes se réorganisent pour accommoder la variation de contraintes auxquelles est soumise l'éprouvette. Le module de cisaillement dynamique M, grandeur directement liée au déphasage accessible par la mesure de spectroscopie mécanique, est un indicateur de l'état de détente du matériau (
Il s'agit de maximiser la différence ΔM100 entre l'état initial avant revenu et celui après revenu pour optimiser la relaxation des contraintes au sein du matériau. L'évolution du module de cisaillement dynamique M100 en fonction de la durée du revenu est étudiée pour le CuZn42 ayant une dureté après mise en forme de 175 HV2. Le comportement à 200°C (T2) et à 180°C (T1) est illustré à la
A la
Pour qualifier l'état de détente d'un matériau, une alternative à la maximisation de ΔM100 est la minimisation de la déformation d'une jauge spécifiquement conçue pour représenter les usinages horlogers de ponts ou tout autre composant horloger usiné dans une pièce semi-finie en bande laminée ou sous forme de barre. La jauge de déformation a une géométrie choisie de sorte à se déformer, préférablement par flambage, lors de son détachement de la matrice dans laquelle elle est usinée. Sa géométrie préférablement circulaire est caractérisée en ce que le rapport épaisseur/diamètre soit supérieur à 10, préférablement supérieur à 100 et qu'elle soit facilement détachable de la matrice dans laquelle elle est usinée. La conception de la jauge de déformation repose sur le principe du flambage qui veut que lorsque les tensions résiduelles dans la membrane constituant son fond sont supérieures à une valeur critique, la jauge va se déformer en flambant lors de son détachement et atteindre une forme d'équilibre caractéristique de l'état des contraintes résiduelles présentes dans la matière constituant la membrane de la jauge. Afin de garantir une bonne détente du laiton, il s'agit de minimiser le flambage de la jauge lors de son détachement. A titre d'exemple, les mesures ont été réalisées avec une jauge dont la géométrie est représentée à la
La planéité est évaluée à partir de la mesure optique de la distribution des hauteurs du fond de la jauge réalisée par microscopie confocale en lumière blanche (instrument FRT Microprof avec posage dédié assurant la reproductibilité du positionnement de la jauge). La valeur de la hauteur z est mesurée par pas de 0.2 mm en x et en y. La topographie de la surface interne du fond est établie en s'affranchissant des effets de la rugosité résiduelle par moyennage de la valeur de z calculée sur une surface de 1 mm2 (moyenne sur environ 25 points). L'éventuelle erreur d'inclinaison globale de la jauge dans le posage est réduite par soustraction du plan moyen de la pièce. On obtient ainsi la distribution des valeurs des résidus zi au plan moyen. La planéité P est définie comme l'écart séparant deux plans parallèles contenant l'ensemble de la surface, quantifiée par la valeur zmax - zmin. La déformation relative de la jauge est évaluée entre l'état "attaché" et l'état "détaché", par soustraction point par point des deux topographies za(x;y) et zd(x;y) . La déformation maximale (planéité relative) est obtenue en prenant la valeur maximale de la différence des hauteurs, soit max|zd-za|.The flatness is evaluated from the optical measurement of the distribution of the heights of the bottom of the gauge carried out by confocal microscopy in white light (FTR Microprof instrument with dedicated mounting ensuring the reproducibility of the positioning of the gauge). The value of the height z is measured in steps of 0.2 mm in x and in y. The topography of the internal surface of the bottom is established by freeing itself from the effects of the residual roughness by averaging the value of z calculated on a surface of 1 mm 2 (average over approximately 25 points). The possible overall tilt error of the gauge in the layout is reduced by subtracting the mean plane of the part. We thus obtain the distribution of the values of the residuals z i in the mean plane. The flatness P is defined as the deviation separating two parallel planes containing the entire surface, quantified by the value z max - z min . The relative deformation of the gauge is evaluated between the "attached" state and the "detached" state, by point-by-point subtraction of the two topographies z a (x;y) and z d (x;y) . The maximum deformation (relative flatness) is obtained by taking the maximum value of the height difference, ie max|z d- z a |.
Les mesures ont été réalisées sur un laiton CuZn42 ayant une dureté à l'état écroui de 173 HV2. A l'état écroui, la déformation maximale est de 7.1 µm. Après un revenu de détente à 180°C pendant 3h, la déformation maximale tombe à 2.2 µm. Sur un laiton CuZn42 ayant une dureté à l'état écroui de 210 HV2, soumis à un traitement de détente à 220°C pendant 1 heure, la déformation maximale est de 2.2 µm. Pour un autre essai réalisé sur une nuance CuZn42 avec une dureté à l'état écroui de 200 HV2 et détendu à 180°C pendant 3 heures, la déformation maximale est de 2.7 µm alors qu'elle est de 4.7 µm à l'état écroui. Ainsi, une déformation maximale inférieure ou égale à 3.5 µm et de préférence à 3 µm est également un indicateur de l'état de détente du matériau.The measurements were carried out on a CuZn42 brass having a work-hardened hardness of 173 HV2. In the hardened state, the maximum deformation is 7.1 µm. After stress relief tempering at 180°C for 3 hours, the maximum strain drops to 2.2 µm. On a CuZn42 brass having a hardness in the work-hardened state of 210 HV2, subjected to a stress-relieving treatment at 220°C for 1 hour, the maximum deformation is 2.2 µm. For another test carried out on a CuZn42 grade with a hardness in the work-hardened state of 200 HV2 and relaxed at 180°C for 3 hours, the maximum deformation is 2.7 µm whereas it is 4.7 µm in the work-hardened state . Thus, a maximum deformation less than or equal to 3.5 μm and preferably 3 μm is also an indicator of the state of relaxation of the material.
La présente invention se rapporte également au composant horloger réalisé dans cet alliage et obtenu à l'issue du procédé décrit ci-avant. Comme susmentionné, ce composant se caractérise par le choix du matériau en laiton CuZn42, par sa dureté avec des valeurs comprises entre 120 et 190 HV2, de préférence entre 150 et 190 HV2, plus préférentiellement entre 170 et 190 HV2, encore plus préférentiellement entre 180 et 190 HV2. Il se caractérise également par son état détendu par opposition à l'état écroui après sa mise en forme par déformation. Pour caractériser cet état sur le produit final, la procédure suivante est utilisée. Le module de cisaillement dynamique M100 est mesuré sur un échantillon prélevé sur le composant horloger. L'échantillon peut être de géométrie planaire (lame) ou cylindrique (fil), la géométrie de l'échantillon n'ayant pas d'impact sur la valeur mesurée. Ensuite, l'échantillon prélevé sur ce même composant est caractérisé dans un banc d'essai de spectroscopie mécanique choisi en fonction de la géométrie de l'échantillon. La variation du module de cisaillement dynamique ΔM100 entre l'état initial avant revenu et celui après revenu est relevée après l'application du protocole de balayage en température 1) décrit précédemment. La durée du maintien est d'une heure à une température de 200°C. Il peut être conclu que le composant est à l'état détendu, et a donc été fabriqué avec le procédé selon l'invention, si le ΔM100 est inférieur à 0.4 GPa, voire à 0.2 GPa, ce qui correspond aux variations du M100 dans la zone "plateau" des
De manière moins préférée, un moyen de différencier un composant horloger détendu selon le procédé de fabrication de l'invention et un composant horloger non détendu peut également consister à mesurer la déformation maximale tel que décrit précédemment sur un échantillon usiné dans le composant horloger, avec une valeur qui doit être inférieure ou égale à la valeur seuil déterminée, pour la géométrie choisie, sur des échantillons de référence usinés dans de la matière détendue. L'éprouvette est conçue de manière à se déformer par flambage lors de sa libération après l'usinage.Less preferably, a means of differentiating a timepiece component relaxed according to the manufacturing method of the invention and a timepiece component that is not relaxed can also consist in measuring the maximum deformation as described above on a sample machined in the timepiece component, with a value which must be less than or equal to the threshold value determined, for the chosen geometry, on reference samples machined in relaxed material. The specimen is designed so that it deforms by buckling when released after machining.
Claims (13)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP21161435.9A EP4057077A1 (en) | 2021-03-09 | 2021-03-09 | Timepiece component made of lead-free brass and manufacturing method thereof |
EP22707131.3A EP4305496A1 (en) | 2021-03-09 | 2022-02-22 | Timepiece component made of lead-free brass, and method for manufacturing same |
PCT/EP2022/054351 WO2022189135A1 (en) | 2021-03-09 | 2022-02-22 | Timepiece component made of lead-free brass, and method for manufacturing same |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP21161435.9A EP4057077A1 (en) | 2021-03-09 | 2021-03-09 | Timepiece component made of lead-free brass and manufacturing method thereof |
Publications (1)
Publication Number | Publication Date |
---|---|
EP4057077A1 true EP4057077A1 (en) | 2022-09-14 |
Family
ID=74867435
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP21161435.9A Withdrawn EP4057077A1 (en) | 2021-03-09 | 2021-03-09 | Timepiece component made of lead-free brass and manufacturing method thereof |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP4057077A1 (en) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2013129876A (en) * | 2011-12-21 | 2013-07-04 | Furukawa Electric Co Ltd:The | Copper alloy material excellent in machinability |
CN112251628A (en) * | 2020-09-14 | 2021-01-22 | 华南理工大学 | High-strength, corrosion-resistant, high-heat-conductivity and free-cutting lead-free environment-friendly silicon brass and preparation and application thereof |
-
2021
- 2021-03-09 EP EP21161435.9A patent/EP4057077A1/en not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2013129876A (en) * | 2011-12-21 | 2013-07-04 | Furukawa Electric Co Ltd:The | Copper alloy material excellent in machinability |
CN112251628A (en) * | 2020-09-14 | 2021-01-22 | 华南理工大学 | High-strength, corrosion-resistant, high-heat-conductivity and free-cutting lead-free environment-friendly silicon brass and preparation and application thereof |
Non-Patent Citations (3)
Title |
---|
J. LAUZIER, J. HILLAIRE, G. GREMAUD |
W BENOIT: "Dislocation-Lattice interactions", MATERIALS SCIENCE FORUM, vol. 366-368, 2001, pages 158 - 177 |
W BENOIT: "Lubrication agents of dislocation motion at very low temperature in cold worked aluminium", J. PHYS. : CONDENS. MATER., vol. 2, 1990, pages 9247, XP020058871, DOI: 10.1088/0953-8984/2/47/002 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP3743538B1 (en) | Pivoting pin of a regulator and manufacturing method therefor | |
FR3126511A1 (en) | "Metastable β titanium alloy clock spring, and its manufacturing process" | |
Molaei et al. | Fatigue performance of additive manufactured metals under variable amplitude service loading conditions including multiaxial stresses and notch effects: Experiments and modelling | |
EP4057077A1 (en) | Timepiece component made of lead-free brass and manufacturing method thereof | |
Torbati-Sarraf et al. | Mechanical properties of ZK60 magnesium alloy processed by high-pressure torsion | |
CH718413A2 (en) | Watch component in lead-free brass and process for its manufacture. | |
EP4305496A1 (en) | Timepiece component made of lead-free brass, and method for manufacturing same | |
EP3796102A1 (en) | Method for manufacturing a balance for a timepiece | |
EP3315620A1 (en) | Non-magnetic precious alloy for clockmaking applications | |
FR3072392B1 (en) | PROCESS FOR PROCESSING A STEEL | |
Wang | Influences of sample preparation on the indentation size effect and nanoindentation pop-in on nickel | |
Liang | High cycle fatigue behavior of additive manufactured stainless steel 316L: free surface effect and microstructural heterogeneity | |
WO2013034851A1 (en) | Method for preparing test parts for the mechanical characterisation of a titanium alloy | |
McElfresh et al. | Fabrication of beryllium capsules with copper-doped layers for NIF targets: A progress report | |
EP0885979B1 (en) | Process for making an article from an oxide dispersion strengthened alloy | |
US4381666A (en) | Method for the nondestructive testing of cellular metallics | |
EP4113220A1 (en) | Method for surface treatment of a stone, in particular for timepieces | |
EP3050127A1 (en) | Method for preparing a recrystallised silicon substrate with large crystallites | |
Bai et al. | Effect of power spinning on microstructure and wear resistance of high-speed laser cladding Fe-based coating | |
Carton | Mechanical properties of thin silicon wafers for photovoltaic applications: Influence of material quality and sawing process | |
EP3511780A1 (en) | Method for lubricating an escapement | |
FR2897433A1 (en) | Test piece forming method for measuring e.g. mechanical resistance property, involves forming test piece having larger thickness than final test piece by fabrication process e.g. molding process | |
US20110103994A1 (en) | Method and apparatus for producing a lightweight metal alloy | |
Avcil et al. | Influence of Sliding Rate and Load with Friction on NiTi Shape Memory Alloy Wear Resistance | |
EP1899087B1 (en) | Method for continuously controlling the thickness of the base of extruded blanks of aerosol containers |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN PUBLISHED |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20230315 |