FR2843128A1 - COPPER ALLOY, NICKEL FREE, COPPER TYPE, MANGANESE, SILICON - Google Patents

Abstract

The present invention relates to a new alloy based on copper, manganese, silicon, substantially nickel-free. This alloy is characterized in that it comprises, by weight, a proportion of copper which is the balance at 100%, a proportion of manganese, which is between 5 and 25%, a proportion in silicon, which is greater than 0.3% and less than or equal to 5%. This alloy finds use as an alternative alloy to copper alloys containing nickel, in the field of eyewear, costume jewelry, leather goods, metal buttonholes, cutlery and cutlery, coins and medals.

Description

1 2843128

  The present invention essentially relates to an alloy based on

  copper, manganese, silicon and substantially nickel-free.

  The present invention relates to a new alloy of copper, manganese, silicon having the property of structural hardening by

heat treatment.

  This alloy is particularly advantageous for use in

skin contact.

  According to another characteristic of the invention, this alloy is advantageously obtained by conventional means of manufacturing and processing. More specifically, the present invention essentially relates to a new alloy of copper, manganese, silicon containing a proportion of copper, which is the balance of the proportion at 100%, and a proportion of manganese which is less than 25%, a proportion of silicon. , which is less than 5%; the percentages being expressed as a percentage in

weight of the total composition.

  The present invention also relates to the use of this alloy in industry, such as in particular the eyewear industry, costume jewelery, leather goods, metal buttons, cutlery and cutlery,

  coins and medals, medical and surgical devices.

  The present invention also relates to the use of this alloy as a substitute alloy for alloys, in particular copper alloys, comprising nickel, thus avoiding the presence of nickel, which causes

  some people have allergies.

  The present invention also relates to the use of this alloy

  for its electrical conductivity properties.

2 2843128

STATE OF THE ART

  Copper alloys are used for their mechanical characteristics, however copper alloys comprising nickel are by the new standards in force prohibited on the market for prolonged applications in contact with the skin, when they release

  nickel at a rate> 0.5 pg / cm2 / week.

  Various manufacturers have sought to replace these copper alloys with nickel with copper alloys, substantially nickel free, having the same mechanical characteristics and a similar or comparable ductility. Several patents relate to alternative alloys to

  copper alloys containing nickel.

  In patent DE 198 07 551, the inventors aim in particular to supply a nickel-free copper-tin alloy. However, this alloy does not have the structural hardening properties by heat treatment given its low manganese content (0.05 to 4%)., This alloy is also described as being yellow in color, which is

  contrary to the object of the present invention.

  In patent EP 1 061 148 which aims to provide a nickel-free copper-zinc alloy, the alloy also does not have the properties of structural hardening by heat treatment given the low

silicon content (0 to 0.3%).

  Other copper alloys without nickel are also described in - patent EP 568 094, but the percentage of silicon is low (0 to 0.3%) and it is mentioned the presence of nickel, which is contrary to the present invention ;

3 2843128

  - Patent EP 532,929, but the alloy also has a low silicon content as well as a low manganese content (0.4 to 1.3% Mn); - EP 621 346, but the presence of aluminum is high (4 to

8%).

  These patents do not make it possible to obtain the alloy of the present invention.

GOALS OF THE INVENTION

  The main object of the present invention is to solve the new technical problem which consists in providing a new copper-manganese-silicon alloy, substantially nickel-free, with hardening.

  structural, in particular by heat treatment.

  The main object of the present invention is also to solve the new technical problem which consists in providing a substantially nickel-free alloy as a substitute alloy for copper alloys.

containing nickel.

  The main object of the present invention is also to solve the new technical problem which consists in providing a copper-free nickel-free alloy of substantially white color, in particular curable by heat treatment, in particular to be brought into contact,

  possibly prolonged, with the skin.

  The present invention also aims to provide an alloy without

  substantially white nickel.

  Another object of the present invention is to provide an alloy with high mechanical strengths such as the breaking strength or the

Vickers hardness.

  The present invention also aims to provide an alloy also compatible with the means of preparation and transformation

4 2843128

  conventional, such as in particular drawing, drawing, rolling and

continuous and semi-continuous casting.

  The present invention also aims to provide an alloy also compatible with conventional shaping means, such as in particular folding, stamping, cutting, cold stamping, stamping, etc.

DETAILED DESCRIPTION OF THE INVENTION

  The invention relates to a copper, manganese, silicon alloy, substantially nickel-free, the mechanical properties of which can be improved by structural hardening, in particular by heat treatment. This alloy has high mechanical characteristics, such as breaking strength or Vickers hardness. The inventors understand by "substantially nickel free", the fact that nickel is not added in the manufacturing process of the alloy, however it is possible that the alloy contains nickel in the impurity state, l ideal being that

not behave.

  According to a first aspect, the invention relates to a copper, manganese, silicon alloy, characterized in that it comprises, by weight, a proportion of copper which is the balance at 100%, a proportion of manganese, which is between 5 and 25%, a proportion in silicon,

  which is greater than 0.3 and less than or equal to 5%.

  The alloy must contain a silicon content greater than 0.3% to have the property of structural hardening by heat treatment, in particular aimed at precipitating compounds of the MnxSiy type, which corresponds to a phase rich in manganese and silicon. The inventors cannot to date characterize these compounds in a way

  more precise, especially as to the value of x and y.

2843128

  Advantageously, the alloy comprises tin, preferably in

  a proportion of between 0.1 and 8% by weight.

  Tin promotes the formation of a delta phase (6) in the raw pouring state. Advantageously, the proportion by weight of manganese is

  between 5 and 20%, preferably from 7 to 15%.

  Advantageously, the proportion by weight of silicon is greater than 0.3 and less than or equal to 3%, preferably between 0.5 and

  2%. This proportion can be 0.35%, for example.

  Advantageously the proportion by weight of tin is understood

  between 0.1 and 3%, preferably between 1 and 2%.

  According to an advantageous embodiment, the invention relates to a copper, manganese, silicon alloy, characterized in that it comprises in proportion by weight approximately:

  1 5 88% copper; 7% Manganese; 3% tin; 2% silicon.

  According to another advantageous embodiment, the invention relates to a copper, manganese, silicon alloy, characterized in that it comprises in proportion by weight approximately:

  84% copper; 15% Manganese; 1% silicon.

  According to another advantageous embodiment, the invention relates to a copper, manganese, silicon alloy, characterized in that it comprises in proportion by weight approximately:

  84.5% copper; 15% Manganese; 0.5% silicon.

  According to another advantageous embodiment, the invention relates to a copper, manganese, silicon alloy, characterized in that it comprises in proportion by weight approximately:

  83% copper; 15% Manganese; 1% tin; 1% silicon.

6 2843128

  According to another advantageous embodiment, the invention relates to a copper, manganese, silicon alloy, characterized in that it comprises in proportion by weight approximately:

  82% copper; 15% Manganese; 2% tin; 1% silicon.

  According to another advantageous embodiment, the invention relates to a copper, manganese, silicon alloy, characterized in that it comprises in proportion by weight approximately:

  81% copper; 15% Manganese; 3% tin; 1% silicon.

  According to another advantageous embodiment, the alloy comprises zinc, preferably in a proportion of less than approximately 25%, and / or aluminum, preferably in a proportion of less than approximately 3%, and / or iron , preferably in a proportion less than about 5%, and / or magnesium, preferably in a proportion less than about 1%, and / or lead, preferably in a proportion less than about 1%, and / or tellurium, preferably in

  a proportion less than or equal to 1%.

  Advantageously, the alloy has a phase rich in manganese

and silicon.

  Advantageously, the alloy is substantially nickel-free.

  Advantageously, the alloy, in the raw casting state, has a

  two-phase structure, comprising a phase rich in manganese and silicon.

  Advantageously, the alloy, in the crude state of casting, also exhibits a de type phase when tin is present in the

proportions of the invention.

  One can in particular produce ingots verifying these compositions in an oven, for example a Balzers oven under controlled atmosphere. These ingots, obtained by static casting, made it possible to achieve a

7 2843128

  metallurgical characterization (Vickers hardness, structure, malleability) of

the raw state of casting.

  According to a second aspect, the present invention relates to a method

  for manufacturing the alloy described above.

  Advantageously, this manufacturing process comprises mixing the various constituents in order to obtain the alloy of the present invention

  in the proportions described above.

  Advantageously, the alloy of the present invention is compatible with conventional production and processing means, such as in particular drawing, drawing, rolling and continuous and semi-continuous casting. Advantageously, the alloy of the present invention is compatible with conventional shaping means, such as in particular folding, stamping, cutting, cold stamping, stamping, etc. Advantageously, this alloy (the alloy of the present invention) has undergone a transformation cycle to be hardened, during its manufacturing process. This transformation cycle can contain one or more stages of heat treatment and / or one or more stages of mechanical treatment. This alloy can be technically characterized by

this cycle of transformation.

  The metallurgical states are those known to those skilled in the art:

  for example TB, TD, TF and TH states.

  TB condition: solution heat treatment, which can be intermediate in the transformation range and which can correspond to a delivery condition depending on the customer's use. TF state: TB state + thermal precipitation treatment, which is only practiced at the final stage in order to increase the mechanical properties

of the product to be delivered.

8 2843128

  TD state: TB state + work hardening of x%.

  TH state: TD state + thermal precipitation treatment.

  Advantageously, the process for manufacturing this alloy comprises a heat treatment for homogenization. Advantageously, said homogenization heat treatment comprises a rise in temperature of between 700 and 9000C, preferably around 7500C, for a period greater than or equal to 3 hours, preferably 4 hours. Advantageously, said homogenization heat treatment is followed by rapid cooling, for example the cooling rate is greater than approximately 50C per second. This rapid cooling may be an air quench or a

water quenching.

  Advantageously, the process for manufacturing this alloy comprises a heat treatment for dissolving. During this heat treatment, the phase rich in Mn and Si of said alloy is dissolved in the matrix. This results in a lowering of the mechanical properties of the material, in particular the hardness, the breaking load, the elastic limit and an increase in the elongation which makes it possible to work it again cold (such as for example rolling, drawing , cold stamping, stamping, etc.). Advantageously, said heat treatment for dissolving comprises a rise in temperature greater than or equal to 6000C, preferably greater than or equal to 7000C, for a period of at least 10 minutes, preferably for 1 hour, followed by a rapid cooling, such as by

  example quenching, for example water or air quenching.

  Advantageously, said method for manufacturing this alloy comprises at least one thermal precipitation treatment. This thermal precipitation treatment advantageously leads to the effect of structural hardening. During this precipitation heat treatment, the phase rich in Mn and Si is precipitated. This results in an increase in the mechanical properties of the material, in particular the

  hardness, breaking load, yield strength.

  Advantageously, the precipitation heat treatment is characterized, for example, by a temperature rise of between 300 and 5000 ° C., preferably between 350 and 4500 ° C., for a period of 2 to 4 hours, preferably of 3 hours, followed by a cooling which is indifferent as to its nature. The type of

  cooling is not of major importance for the result to be obtained.

  Advantageously, the method for manufacturing this alloy comprises at least one quenching. This quenching can be carried out with water or air,

for example.

  Advantageously, the process for manufacturing this alloy comprises

  at least one rolling operation.

  Advantageously, rolling makes it possible to harden this alloy, preferably at 100%, it is possible to laminate (or harden) up to 260%. Advantageously, this operation can be inserted between the quenching heat treatment and the heat treatment of

precipitation.

  Advantageously, this alloy has a low electrical conductivity, for example of 3% maximum compared to that of copper

(percentage in I.A.C.S. symbol).

  The electrical conductivity is also measured in percentage I.A.C.S. alloy (International Annealed Cooper Standard), a comparison scale based on the electrical conductivity of pure copper, which

% I.A.C.S.

  The alloy of the present invention has a substantially white color, quite comparable to the alloys traditionally used

containing nickel.

  The absence of nickel makes it possible to be in conformity with the decree relating to the prohibition on the marketing of certain products containing nickel, published in the Official Journal N0165, page 11068, of July 19, 2000, which authorizes its use, in contact with the skin, in particular

when this contact is prolonged.

  According to a third aspect, the invention relates to the use of an alloy as described above or obtained by a manufacturing process as described above, for the partial or complete manufacture of products, articles, parts intended to be put in touch more

or less prolonged with the skin.

  Advantageously, said alloy can be used in the field of eyewear, costume jewelry, leather goods, metal buttonholes,

  cutlery and cutlery, coins and medals.

  Advantageously, said alloy can be used for the partial or complete manufacture of spectacle frames, branches and circles of glasses in particular, earrings, neck and ankle chains, necklaces, rings, curb chains, belt buckles, bag clasps hand, rivet buttons, rivets, zippers, knife bolsters,

  spoons, forks, coins and commemorative medals.

  According to a fourth aspect, the invention relates to the use of an alloy as described above or obtained by a manufacturing process as described above, for the partial or complete manufacturing of at least one part of a medical device, such as a surgical device, for example medical and surgical devices, such

  as epithelialization and surgical staples.

  i1 *. For many of these articles, shaping is most often obtained by cutting, stamping and cold stamping, such as stamping, to obtain decorations, and is facilitated by the good ductility at

  the state of dissolution of the phases rich in manganese and silicon.

  According to a fifth aspect, the invention relates to the use of an alloy as described above or obtained by a manufacturing process as described above, in the fields of electrical engineering and electricity, in particular in the form of resistance , shunts, and / or heating elements, and / or used for its good suitability for

  resistance or spot welding.

  In the examples, any characteristic which will appear to be new compared to any prior art forms an integral part of the present invention and protection is sought in its function and its generality. In particular, the temperature and duration ranges of the heat treatments are given by way of example; those skilled in the art will be able to adjust these various parameters in order to obtain the

desired properties.

  On the other hand, in the description and the claims, all

  percentages are given by weight, the temperature is in degrees Celsius

  and the pressure is atmospheric pressure, unless otherwise indicated.

  EXAMPLES 1 TO 7 ACCORDING TO THE PRESENT INVENTION

  The preparation of the alloy, in the various proportions of its constituents, can be carried out, for example, by the production of an ingot of approximately 1 kg in a balzers oven under controlled atmosphere. These ingots are obtained by static casting and are referenced in the table

  I below by the ingot number which corresponds to the example number.

  These ingots then undergo the following transformation cycle:

12 2843128

  - heat treatment in solution at 700 ° C. for 1 hour followed by rapid cooling with water (state of TB); - laminating (or work hardening) treatment (TD state); - Precipitation heat treatment, at a temperature of 350, 400, 450 or 500 OC for a period of 3 hours, preceded by a hardening operation (TH state) Vickers hardnesses of the various alloy compositions according to the present invention are set out below in Table II according to the metallurgical state. The results expressed in Vickers hardness (HV). By way of illustration of the increase in hardness obtained by a precipitation treatment, the inventors have indicated the Vickers hardnesses obtained in the TF state, that is to say after thermal precipitation treatment, at a temperature of 350, 400, 450 or 500 OC during a period of

3 hours.

  The inventors understand by "precipitation", the fact of carrying out a

  precipitation heat treatment.

  Table I: Composition of ingots No Cu Mn Zn Sn Si Fe AI Hardness Hardening rate Ingot (%) (%) (%) (%) (%) (%) Vickers (HV) Possible structure before cracks Type phase ô 1 87 7 0 3 3 0 0 116.5 + rich phase 40% in Mn If the same

2 88 7 0 3 2 0 0 109.5 90%

  Phase rich in 3 84 15 0 0 1 0 0 128.5 Mn and Si> 100% Phase rich in 4 84.5 15 0 0 0.5 0 0 96 Mn and Si> 100% Typical phase ô 83 15 0 1 1 0 0 131.5 + rich phase> 100% in Mn Si 6 82 15 0 2 1 0 0 138 Idem> 100% 7 81 15 0 3 1 0 0 137 Idem> 100% Table II: Vickers hardness of the alloy in different metallurgical states: Raw state of quenched state followed by precipitation heat treatment (TF) after: quenching heat treatment (TB state) Quenched state (TB) followed by work hardening (TD state) Quenched state with work hardening of 100 % followed by a thermal precipitation treatment (TH state) after: NO 7000C - 1h Precipitation Precipitation Precipitation Precipitation work hardening Precipitation Precipitation Precipitation then from 3h to 3h to 3h to 3h to delOO% of 3h to deh 3 to 3h to quench 350OC 4000C 4500C 5000C 3500C 4000C 4500C

  2 86.5 182.5 190 158.5 138 225 285 244.5 218

  3 86 131 210 209.5 174 205.5 263 268 247

  4 80 117.5 164 156 128 202 225 229 212

  89 128.5 211 210 177 212 269 268 237

  6 93 136 210 210 172.5 224.5 269 276.5 242

  7 99.5 136 214 206 171 236.5 269 276.5 244.5

l 5 2843128

  EXAMPLE 8 ACCORDING TO THE PRESENT INVENTION

  The preparation of the alloy, for example of the NI 3 alloy, can be produced industrially, for example to produce an ingot of approximately 2.5 tonnes (format 200 × 400 mm) by semi-continuous casting. The fusion is carried out in an aluminous crucible heated by induction to

  11500C from copper cathode, electrolytic manganese and cuprosilicon.

  After trimming the ingot was preheated to around 850 OC in a gas oven. The hot rolling was carried out on a reversible rolling mill in 15 passes in order to obtain a strip 11.5 mm thick. This 400 mm wide strip was then milled to 10.5 mm and rolled to

  cold to 3.5 mm, which represents 200% hardening.

  The phases rich in manganese and silicon were dissolved by the quenching heat treatment in a passage oven under controlled atmosphere, at a temperature of 700 ° C., followed by cooling with water. From this metallurgical state (raw quenching heat treatment state), it was possible to verify that the hardness obtained, in the different metallurgical states TB, TD, TF and

  TH, correspond well to the values in Table II of Example 3 above.

  EXAMPLE 9 ACCORDING TO THE PRESENT INVENTION

  The alloy of example N03 heat treated at 750-7700C, for half an hour, followed by rapid cooling makes it possible to obtain a hardness of approximately 85 Vickers. From this quenched state or during the heat treatment, the phases rich in manganese and silicon have been dissolved, the ductility of the alloy makes it possible to be hardened by more than 200%; the alloy can therefore withstand significant deformations

  cold stamping for example.

16 2843128

  At the end of the cold deformation, the precipitation of the phases rich in manganese and silicon, by thermal treatment of precipitation of 3 hours at 410-4200C, followed by a slow cooling, gives the part

  no more hardness of around 270 Vickers.

  EXAMPLE 10 to 14 ACCORDING TO THE PRESENT INVENTION

  The following transformation cycles can be carried out, by way of illustration, in order to obtain the alloy of the present invention in the desired metallurgical state:

  EXAMPLE 10 ACCORDING TO THE PRESENT INVENTION

  The alloy can for example undergo the following transformation cycle for

be obtained in TB state.

  l 5 transformation cycle Preparation of an ingot 400 x 200 x 3500 Homogenization treatment between 750 and 8500C for 3 to 6 hours, indifferent cooling Hot rolling from 200 mm to 11 mm Cold rolling from 11 mm to 3 mm ( approximately 260% of work hardening) Thermal treatment of solution setting Rolling of 3 to 1.5 mm (hardening 100%) Thermal treatment of solution The ingot has a thickness of 1.5 mm and a state TB. The Vickers hardnesses of the various compositions of the alloy of the present invention

  correspond to the values in table II for this metallurgical state.

17 2843128

  EXAMPLE 11 ACCORDING TO THE PRESENT INVENTION

  The alloy can for example undergo the following transformation cycle for

be obtained in the TH state.

  transformation cycle Preparation of an ingot 400 x 200 x 3500 Homogenization treatment between 750 and 8500C for 3 to 6 hours, indifferent cooling Hot rolling from 200 mm to 11 mm Cold rolling from 11 mm to 3 mm (about 260 % work hardening) Thermal solution treatment Laminating from 3 to 1.5 mm (100% work hardening) Precipitation thermal treatment The ingot has a thickness of 1.5 mm and a TH state. The Vickers hardnesses of the various compositions of the alloy of the present invention

  correspond to the values in table II for this metallurgical state.

  EXAMPLE 12 ACCORDING TO THE PRESENT INVENTION

  The alloy can for example undergo the following transformation cycle for

be obtained in TD state.

  transformation cycle Preparation of an ingot 400 x 200 x 3500 Homogenization treatment between 750 and 8501C for 3 to 6 hours, indifferent cooling Hot rolling from 200 mm to 11 mm Cold rolling from 11 mm to 3 mm (about 260 % cold work) Solution heat treatment Laminating from 3 to 1.5 mm (100% work hardening) The ingot has a thickness of 1.5 mm and a TD state. The Vickers hardnesses of the various compositions of the alloy of the present invention

  correspond to the values in table II for this metallurgical state.

  EXAMPLE 13 ACCORDING TO THE PRESENT INVENTION

  The alloy can for example undergo the following transformation cycle for

be obtained in the TF state.

  transformation cycle Preparation of an ingot 400 x 200 x 3500 Homogenization treatment between 750 and 8500C for 3 to 6 hours, indifferent cooling Hot rolling from 200 mm to 11 mm Cold rolling from 11 mm to 3 mm (about 260 % cold work) Solution heat treatment Laminating from 3 to 1.5 mm (100% work hardening) Solution heat treatment Heat precipitation treatment The ingot is 1.5 mm thick and TF state. The Vickers hardnesses of the various compositions of the alloy of the present invention

  correspond to the values in table II for this metallurgical state.

  EXAMPLE 14 ACCORDING TO THE PRESENT INVENTION

  The alloy can for example undergo the following transformation cycle for

be obtained in TD state.

  transformation cycle Preparation of an ingot 400 x 200 x 3500 Homogenization treatment between 750 and 8500C for 3 to 6 hours, indifferent cooling Hot rolling from 200 mm to 11 mm Cold rolling from 11 mm to 3 mm (about 260 % of work hardening) Thermal treatment of solution Rolling from 3 to 1 mm (work hardening 200%) Thermal treatment of solution Rolling from t to 0.3 mm (work hardening 230%) 1 0 Heat treatment of solution making Rolling of 0.3 at 0.25 mm (20% work hardening) The ingot has a thickness of 0.25 mm and a TD state. The Vickers hardnesses of the various compositions of the alloy of the present invention

  1 5 correspond to the values in Table II for this metallurgical state. EXAMPLE 15 ACCORDING TO THE PRESENT INVENTION

  Electrical conductivity test The alloys, as described in examples i to 7, are subjected to electrical conductivity tests in order to verify their adaptation in the fields of electrical engineering and electricity. This also makes it possible to characterize these alloys according to their metallurgical state. The electrical tests consist in calculating the value of electrical resistivity, quantity which determines the behavior of the alloy. The electrical electrical conductivity is also measured in% I.A.C.S. of the alloy (International Annealed Cooper Standard), a comparison scale based on the electrical conductivity of pure copper, which makes 100% I.A.C.S. The values of the conductivities in table III are given according to the composition and the metallurgical state. Bullion numbers

  correspond to those in Table I of Examples 1 to 7.

  Table III: Electrical conductivity of the alloy in% I.A.C.S as a function of the metallurgical state.

  TB state after: TF state after: TD state after: TH state after: 700 OC Precipitation Precipitation Precipitation Precipitation Work hardening N 1h then 3 H to 3 H to 3 H to 3 H to 100% Precipitation Precipitation Precipitation hardening 350 C 400 OC 450 C 500 OC de3Hà350 de3Hà400 de3Hà450 eau OC OC OC

  2 3.8 5.8 5.4 5.4 5.2 3.95 6.65 6.5 6.3

3 2.8 3.8 4 3.9 3.7 2.9 4.3 4.4 4.3

  4 3 3.5 3.65 3.6 3.4 3.15 3.9 3.9 3.9

  2.75 3.6 3.9 3.8 3.6 2.8 4.1 4.3 4.2

  6 2.7 3.5 3.7 3.6 3.45 2.75 3.95 4 4

  7 2.65 3.4 3.6 3.55 3.4 2.75 3.8 3.95 3.9

22 2843128

Claims (27)

  1. Alloy copper, manganese, silicon, characterized in that it comprises, by weight, a proportion of copper which is the balance at 100%, a proportion of manganese, which is between 5 and 25%, a proportion of silicon , which is greater than 0.3 and less than or equal to%. 2. Alloy according to claim 1, characterized in that it comprises tin, preferably in a proportion of between 0.1 and 8% by weight.   3. Alloy according to claim 1, characterized in that the proportion by weight of manganese is between 5 and 20%, preferably of 7 to 15%.   4. Alloy according to claim 1, characterized in that the proportion by weight of silicon is greater than 0.3 and less than or equal to 3%, of   preferably between 0.5 and 2%.   5. Alloy according to claim 2, characterized in that the proportion by weight of tin is between 0.1 and 3%, preferably between between 1 and 2%.   6. Alloy according to claim 2, characterized in that it comprises, in proportion by weight approximately:   88% copper; 7% Manganese; 3% tin; 2% silicon.   7. Alloy according to claim 1, characterized in that it comprises, in proportion by weight approximately:   84% copper; 15% Manganese; 1% silicon.   8. Alloy according to claim 1, characterized in that it comprises, in proportion by weight approximately:   84.5% copper; 15% Manganese; 0.5% silicon.   23 9. Alloy according to claim 2, characterized in that it comprises, in proportion by weight approximately:   83% copper; 15% Manganese; 1% tin; 1% silicon.   10. Alloy according to claim 2, characterized in that it comprises, in proportion by weight approximately:   82% copper; 15% Manganese; 2% tin; 1% silicon.   11. Alloy according to claim 2, characterized in that it comprises, in proportion by weight approximately:   81% copper; 15% Manganese; 3% tin; 1% silicon.   12. Alloy according to any one of claims 1 to 11,   characterized in that it comprises zinc, preferably in a proportion less than approximately 25%, and / or aluminum, preferably in a proportion less than approximately 3%, and / or iron, preferably in a proportion less than approximately 5%, and / or magnesium, preferably in a proportion less than approximately 1%, and / or lead, preferably in a proportion less than approximately 1%, and / or   tellurium, preferably in a proportion less than or equal to 1 0 /%.   13. Alloy according to any one of the preceding claims,   characterized in that it has a phase rich in manganese and silicon.   14. Alloy according to any one of the preceding claims,   characterized in that it is substantially nickel free.   15. Method for manufacturing the alloy, as defined in any one   of claims 1 to 14, characterized in that it comprises at least one   homogenization heat treatment.   16. Method according to claim 15, characterized in that said homogenization heat treatment comprises a temperature rise between 700 and 9000C, preferably around 7500C, for a period greater than or equal to 3 hours, preferably   4 hours, possibly followed by rapid cooling.   17. Method according to claim 15 or 16, characterized in that it   includes at least one solution treatment.   18. Method according to any one of claims 15 to 17,   characterized in that said solution treatment includes a rise in temperature greater than or equal to 6000C, preferably greater than or equal to 7000C, for a period of at least 10 minutes,   preferably for 1 hour, followed by rapid cooling.   19. Method according to any one of claims 15 to 18,   characterized in that it comprises at least one thermal precipitation treatment.   20. Method according to any one of claims 15 to 19,   characterized in that said precipitation heat treatment l 5 comprises a temperature rise between 300 and 5001C, preferably between 350 and 4500C, during a period of 2 to 4   hours, preferably 3 hours, followed by cooling.   21. Method according to any one of claims 15 to 20,   characterized in that it comprises at least one quench.   22. Method according to any one of claims 15 to 21,   characterized in that it comprises at least one rolling or work hardening operation. 23. Use of an alloy, as defined in any one of   claims 1 to 14 or as obtained by a process as defined in   any one of claims 15 to 22, for the partial manufacture   or complete of products, articles, parts intended to be put in contact   more or less prolonged with the skin.   24. Use according to claim 23, in the field of eyewear, costume jewelry, leather goods, metal buttonholes,   cutlery and cutlery, coins and medals.   25. Use according to claim 23 or 24, characterized in that said alloy can be used for the manufacture of spectacle frames, branches and circles of glasses in particular, earrings, neck and ankle chains, necklaces, rings, curb chains , belt buckles, handbag clasps, rivet buttons, rivets, zippers, knife bolsters, spoons, forks, coins and medals 1 0 commemorative.   26. Use of an alloy as described according to any one of   claims 1 to 14, or as obtained by a process as defined in   any one of claims 15 to 22, for the partial manufacture   or complete with at least one part of a medical device, such as a surgical device, for example medical and surgical devices such   as epithelialization and surgical staples.   27. Use of an alloy as described according to any one of   claims 1 to 14, or as obtained by a process as defined in   any one of claims 15 to 22, characterized in that said   alloy is used in the fields of electrical engineering and electricity, in particular in the form of resistance, shunts, and / or heating elements, and / or used for its good ability to spot resistance welding or wheel.