(19)
(11)EP 2 971 199 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
02.09.2020 Bulletin 2020/36

(21)Application number: 14769653.8

(22)Date of filing:  11.03.2014
(51)International Patent Classification (IPC): 
C22C 9/06(2006.01)
C22F 1/08(2006.01)
(86)International application number:
PCT/US2014/023522
(87)International publication number:
WO 2014/150532 (25.09.2014 Gazette  2014/39)

(54)

METHOD FOR PRODUCING ULTRA HIGH STRENGTH COPPER-NICKEL-TIN ALLOYS

VERFAHREN ZUR HERSTELLUNG VON ULTRAHOCHFESTEN KUPFER-NICKEL-ZINN-LEGIERUNGEN

PROCÉDÉ DE FABRICATION DES ALLIAGES DE CUIVRE-NICKEL-ÉTAIN DE RÉSISTANCE ULTRA ÉLEVÉE


(84)Designated Contracting States:
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

(30)Priority: 14.03.2013 US 201361781942 P

(43)Date of publication of application:
20.01.2016 Bulletin 2016/03

(73)Proprietor: Materion Corporation
Mayfield Heights, OH 44124 (US)

(72)Inventors:
  • WETZEL, John F.
    Mayfield Heights, Ohio 44124 (US)
  • SKORASZEWSKI, Ted
    Mayfield Heights, Ohio 44124 (US)

(74)Representative: Kador & Partner PartG mbB 
Corneliusstraße 15
80469 München
80469 München (DE)


(56)References cited: : 
US-A- 3 198 499
US-A- 4 260 432
US-A- 5 089 057
US-A- 3 198 499
US-A- 5 089 057
US-A1- 2003 047 259
  
  • ???: "Designation: B 740 - 02 Standard Specification for Copper-Nickel-Tin Spinodal Alloy Strip2 ASTM Standards: B 248 Specification for General Requirements for Wrought Copper and Copper-Alloy Plate, Sheet, Strip, and Rolled Bar 2 B 598 Practice for Determining Offset Yield Strength in Tension for Copper", ASTM INTERNATIONAL, 31 December 2002 (2002-12-31), XP055322960,
  • Anonymous: "Materion Brush Performance Alloys Cold Rolled Temper Designations for BrushForm 158 Minimum 90° Bend Formability R/T Ratio Standard Designation ASTM Designation", MATERION, 31 December 2011 (2011-12-31), XP055289069, Retrieved from the Internet: URL:http://materion.com/~/media/Files/PDFs /Alloy/DataSheets/Copper Nickel Tin Strip/Brushforms-DataSheets-Brushform158Co ldRolled [retrieved on 2016-07-18]
  • 'BrushForm(R) 158 Cold Rolled Tempers. Datasheet' MATERION 2011, page 1, XP055289069 Retrieved from the Internet: <URL:http://materion.com/~/media/Files/PDFs /Alloy/DataSheets/Copper%20Nickel%20Tin%20S trip/Brushforms-DataSheets-Brushform158Cold Rolled.pdf> [retrieved on 2014-05-19]
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

BACKGROUND



[0001] The present disclosure relates to ultra high strength wrought copper-nickel-tin alloys and processes for enhancing the yield strength characteristics of the copper-nickel-tin alloy. In particular, the copper-nickel-tin alloys undergo a processing method that results in substantially higher strength levels from known alloys and processes, and will be described with particular reference thereto.

[0002] Copper-beryllium alloys are used in in voice coil motor (VCM) technology. VCM technology refers to various mechanical and electrical designs that are used to provide high-resolution, auto-focus, optical zooming camera capability in mobile devices. This technology requires alloys that can fit within confined spaces that also have reduced size, weight and power consumption features to increase portability and functionality of the mobile device. Copper-beryllium alloys are utilized in these applications due to their high strength, resilience and fatigue strength.

[0003] Some copper-nickel-tin alloys have been identified as having desirable properties similar to those of copper-beryllium alloys, and can be manufactured at a reduced cost. For example, a copper-nickel-tin alloy offered as Brushform® 158 (BF 158) by Materion Corporation, is sold in various forms and is a high-performance, heat treated alloy that allows a designer to form the alloy into electronic connectors, switches, sensors, springs and the like. These alloys are generally sold as a wrought alloy product in which a designer manipulates the alloy into a final shape through working rather than by casting. However, these copper-nickel-tin alloys have formability limitations compared to copper-beryllium alloys.

[0004] The publication "designation: B740-02 Standard specification for copper-nickel-tin spimodal alloy strip 2 ASTM standards" (2002-01-01) discloses a Cu-Ni-Sn spimodal alloy strip made of the standard alloy C72900 (77Cu-15Ni-8Sn) and a process for producing such alloys. US 5,089,057 discloses Copper based alloys, e.g. CuNiSnSi are processed by annealing followed by a high level of cold work area reduction then a recrystallization step which is followed by a low level of cold work prior to spinodal aging. The resultant material is isotropically formable while maintaining high yield strength. US 4,260,432 A discloses alloys which contain Cu, Ni, Sn, and prescribed amounts of Mo, Nb, Ta, V, or Fe. A predominantly spinodal structure is developed in such alloys by a treatment which requires annealing, quenching, and aging, and which does not require cold working to develop alloy properties. The publication "Materion brush performance alloys coal role temper designations for brush form 158 minimum 90° band formability R/T ratio standard designation ASTM designation", Materion (2011 - 01-01) discloses the Materion brush performance alloys brush form 158 strip which is a high-performance, heat treatable spimodal copper, nickel, tin, alloy designed to provide optimal formability and strength characteristics in conductive string applications such as electronic connectors, switches and sensors.

[0005] Therefore, it would be desirable to develop new ultra high strength copper-nickel-tin alloys and processes for that would improve the yield strength characteristics of such alloys.

BRIEF DESCRIPTION



[0006] The present invention relates to a method to improve the 0.2% offset yield strength (hereinafter abbreviated "yield strength") of a copper-nickel-tin alloy such that the resulting yield strength is at least 1207 MPa (175 ksi) according to claim 1. Generally, the alloy is first mechanically cold worked to undergo a plastic deformation %CW (i.e. percentage cold working) of 50% to 75%. The alloy then undergoes a thermal stress relief step by heating to an elevated temperature between 393°C (740°F) and 454°C (850°F) for a period of between 3 minutes and 14 minutes to produce the desired formability characteristics. The copper alloy consists of 9-15.5 wt% nickel, 6-9 wt% tin and the remaining balance being copper.

[0007] These and other non-limiting characteristics of the disclosure are more particularly disclosed below.

BRIEF DESCRIPTION OF THE DRAWINGS



[0008] The following is a brief description of the drawings, which are presented for the purposes of illustrating the exemplary embodiments disclosed herein and not for the purposes of limiting the same.

FIG. 1 is a flow chart illustrating an exemplary method of the present disclosure.

FIG. 2 is a graph showing the 0.2% offset yield strength versus line speed at different temperatures.


DETAILED DESCRIPTION



[0009] A more complete understanding of the components, processes and apparatuses disclosed herein can be obtained by reference to the accompanying drawings. These figures are merely schematic representations based on convenience and the ease of demonstrating the present disclosure, and are, therefore, not intended to indicate relative size and dimensions of the devices or components thereof and/or to define or limit the scope of the exemplary embodiments.

[0010] Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of the embodiments selected for illustration in the drawings, and are not intended to define or limit the scope of the disclosure. In the drawings and the following description below, it is to be understood that like numeric designations refer to components of like function.

[0011] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0012] As used in the specification and in the claims, the terms "comprise(s)," "include(s)," "having," "has," "can," "contain(s)," and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that require the presence of the named ingredients/steps and permit the presence of other ingredients/steps. However, such description should be construed as also describing compositions or processes as "consisting of" and "consisting essentially of" the enumerated ingredients/steps, which allows the presence of only the named ingredients/steps, along with any unavoidable impurities that might result therefrom, and excludes other ingredients/steps.

[0013] Numerical values in the specification and claims of this application should be understood to include numerical values which are the same when reduced to the same number of significant figures and numerical values which differ from the stated value by less than the experimental error of conventional measurement technique of the type described in the present application to determine the value.

[0014] All ranges disclosed herein are inclusive of the recited endpoint and independently combinable (for example, the range of "from 2 grams to 10 grams" is inclusive of the endpoints, 2 grams and 10 grams, and all the intermediate values).

[0015] Percentages of elements should be assumed to be percent by weight of the stated alloy, unless expressly stated otherwise.

[0016] As used herein, the term "spinodal alloy" refers to an alloy whose chemical composition is such that it is capable of undergoing spinodal decomposition. The term "spinodal alloy" refers to alloy chemistry, not physical state. Therefore, a "spinodal alloy" may or may not have undergone spinodal decomposition and may or not be in the process of undergoing spinodal decomposition.

[0017] Spinodal aging/decomposition is a mechanism by which multiple components can separate into distinct regions or microstructures with different chemical compositions and physical properties. In particular, crystals with bulk composition in the central region of a phase diagram undergo exsolution. Spinodal decomposition at the surfaces of the alloys of the present disclosure results in surface hardening.

[0018] Spinodal alloy structures are made of homogeneous two phase mixtures that are produced when the original phases are separated under certain temperatures and compositions referred to as a miscibility gap that is reached at an elevated temperature. The alloy phases spontaneously decompose into other phases in which a crystal structure remains the same but the atoms within the structure are modified but remain similar in size. Spinodal hardening increases the yield strength of the base metal and includes a high degree of uniformity of composition and microstructure.

[0019] The copper-nickel-tin alloy utilized herein consists of 9.0 wt% to 15.5 wt% nickel, and from 6.0 wt% to 9.0 wt% tin, with the remaining balance being copper. This alloy can be hardened and more easily formed into high yield strength products that can be used in various industrial and commercial applications. This high performance alloy is designed to provide properties similar to copper-beryllium alloys.

[0020] More particularly, the copper-nickel-tin alloys of the present disclosure consists of 9 wt% to 15 wt% nickel and 6 wt% to 9 wt% tin, with the remaining balance being copper. In more specific embodiments, the copper-nickel-tin alloys consists of 14.5 wt% to 15.5% nickel, and 7.5 wt% to 8.5 wt% tin, with the remaining balance being copper. These alloys can have a combination of various properties that separate the alloys into different ranges. The present disclosure is directed towards alloys that are designated TM12. More specifically, "TM12" refers to copper-nickel-tin alloys that generally have a 0.2% offset yield strength of at least 1207 MPa (175 ksi), an ultimate tensile strength of at least 1241 MPa (180 ksi), and a minimum %elongation at break of 1%. To be considered a TM12 alloy, the yield strength of the alloy must be a minimum of 1207 MPa (175 ksi).

[0021] FIG. 1 is a flowchart that outlines the steps of the metal working processes of the present disclosure for obtaining a TM12 alloy. The metal working process begins by first cold working the alloy 100. The alloy then undergoes a heat treatment 200.

[0022] Cold working is the process of mechanically altering the shape or size of the metal by plastic deformation. This can be done by rolling, drawing, pressing, spinning, extruding or heading of the metal or alloy. When a metal is plastically deformed, dislocations of atoms occur within the material. Particularly, the dislocations occur across or within the grains of the metal. The dislocations over-lap each other and the dislocation density within the material increases. The increase in over-lapping dislocations makes the movement of further dislocations more difficult. This increases the hardness and tensile strength of the resulting alloy while generally reducing the ductility and impact characteristics of the alloy. Cold working also improves the surface finish of the alloy. Mechanical cold working is generally performed at a temperature below the recrystallization point of the alloy, and is usually done at room temperature. The percentage of cold working (%CW), or the degree of deformation, can be determined by measuring the change in the cross-sectional area of the alloy before and after cold working, according to the following formula:

where A0 is the initial or original cross-sectional area before cold working, and Af is the final cross-sectional area after cold working. It is noted that the change in cross-sectional area is usually due solely to changes in the thickness of the alloy, so the %CW can also be calculated using the initial and final thickness as well.

[0023] The initial cold working step 100 is performed on the alloy such that the resultant alloy has a plastic deformation in a range of 50%-75% cold working. More particularly, the cold working % achieved by the first step can be 65%.

[0024] The alloy then undergoes a heat treatment step 200. Heat treating metal or alloys is a controlled process of heating and cooling metals to alter their physical and mechanical properties without changing the product shape. Heat treatment is associated with increasing the strength of the material but it can also be used to alter certain manufacturability objectives such as to improve machining, improve formability, or to restore ductility after a cold working operation. The heat treating step 200 is performed on the alloy after the cold working step 100. The alloy is placed in a traditional furnace or other similar assembly and then exposed to an elevated temperature in the range of 393°C (740°F) to 454 °C (850°F) for a time period of from 3 minutes to 14 minutes. It is noted that these temperatures refer to the temperature of the atmosphere to which the alloy is exposed, or to which the furnace is set; the alloy itself does not necessarily reach these temperatures. This heat treatment can be performed, for example, by placing the alloy in strip form on a conveyor furnace apparatus and running the alloy strip at a rate of -152 cm/min (5 ft/min) through the conveyor furnace. In more specific embodiments, the temperature is from - 393°C (740°F) to 427°C (800°F).

[0025] This process achieves a yield strength level for the ultra high strength copper-nickel-tin alloy that is at least 1207 Mpa (175 ksi). This process has consistently been identified to produce alloy having a yield strength in the range of - 1207 MPa (175 ksi) to 1310 MPa (190 ksi). More particularly, this process can process alloy with a resulting yield strength (0.2% offset) of 1227 MPa (178 ksi) to 1275 MPa (185 ksi).

[0026] A balance is reached between cold working and heat treating. There is an ideal balance between an amount of strength that is gained from cold working wherein too much cold working can adversely affect the formability characteristics of this alloy. Similarly, if too much strength gain is derived from heat treatment, formability characteristics can be adversely affected. The resulting characteristics of the TM12 alloy include a yield strength that is at least 1207 MPa (175 ksi). This strength characteristic exceeds the strength features of other known similar copper-nickel-tin alloys.

[0027] The following examples are provided to illustrate the alloys, articles, and processes of the present disclosure. The examples are merely illustrative and are not intended to limit the disclosure to the materials, conditions, or process parameters set forth therein.

EXAMPLES



[0028] Copper-nickel-tin alloys containing 15 wt% nickel, 8 wt% tin, and balance copper were formed into strips. The strips were then cold worked using a rolling assembly. The strips were cold worked and measured at %CW of 65%. Next, the strips underwent a heat treatment step using a conveyor furnace apparatus. The conveyor furnace was set at temperatures of 393°C, 404°C, 415°C, 426°C, 440°C or 454°C (740°F, 760°F, 780°F, 800°F, 825°F, or 850°F). The strips were run through the conveyor furnace at a line speed of 152, 305, 457, or 610 cm/min (5, 10, 15, or 20 ft/min). Two strips were used for each combination of temperature and speed.

[0029] Various properties were then measured. Those properties included the ultimate tensile strength (T) in ksi; the 0.2% offset yield strength (Y) in ksi; the % elongation at break (E); and the Young's modulus (M) in millions of pounds per square inch (10^6 psi). Table 1 and Table 2 provide the measured results. The average values for T and Y are also provided. Table 1a and Table 2a provide the respective SI values for temperatures and line speed and the properties measured. That is Temp in °C, line speed in cm/min, (T) in MPa; the 0.2% offset yield strength (Y) in MPa; and the Young's modulus (M) in MPa.
Table 1.
TempFPMTYAvq TAvq YEM
740 5 187.1 180.6     1.77 16.88
740 5 183.3 180.0 185.2 180.3 1.43 16.89
740 10 179.2 173.5     1.73 16.93
740 10 180.7 175.4 180.0 174.5 1.64 16.89
740 15 175.0 171.2     1.54 16.95
740 15 173.8 168.9 174.4 170.0 1.60 17.00
740 20 168.2 161.6     1.61 16.64
740 20 171.0 165.9 169.6 163.7 2.05 16.98
760 5 190.4 182.0     1.83 16.72
760 5 187.8 181.6 189.1 181.8 1.62 16.78
760 10 183.4 176.8     1.60 16.90
760 10 183.1 174.4 183.3 175.6 2.00 16.80
760 15 178.3 170.2     1.97 16.89
760 15 181.1 173.5 179.7 171.8 1.90 16.76
760 20 174.9 168.2     1.61 16.86
760 20 173.5 165.3 174.2 166.8 2.03 16.64
780 5 188.9 180.0     1.80 16.55
780 5 189.8 181.8 189.4 180.6 1.68 16.78
780 10 186.4 177.7     1.84 16.88
780 10 185.7 178.0 186.1 177.8 1.67 16.82
780 15 181.8 173.7     1.91 16.86
780 15 181.1 172.8 181.5 173.2 1.99 16.89
780 20 176.3 167.6     1.80 16.76
780 20 179.1 171.2 177.7 169.4 1.83 16.81
Table 1a
TempTemp (°C)FPM (cm/min)T (Mpa)Y (MPa)Avg T (Mpa)Avg Y (Mpa)M (MPa)
740 393 152 1290 1245     116371
740 393 152 1264 1241 1277 1243 116440
740 393 305 1235 1196     116715
740 393 305 1246 1209 1241 1203 116440
740 393 457 1206 1180     116853
740 393 457 1198 1165 1202 1172 117198
740 393 610 1160 1114     114716
740 393 610 1179 1144 1169 1129 117060
760 404 152 1313 1255     115268
760 404 152 1295 1252 1304 1253 115681
760 404 305 1264 1219     116509
760 404 305 1262 1202 1264 1211 115819
760 404 457 1229 1173     116440
760 404 457 1249 1196 1239 1185 115543
760 404 610 1206 1160     116233
760 404 610 1196 1140 1201 1150 114716
780 416 152 1302 1241     114096
780 416 152 1308 1253 1306 1245 115681
780 416 305 1285 1225     116371
780 416 305 1280 1227 1283 1226 115957
780 416 457 1253 1198     116233
780 416 457 1249 1191 1251 1194 116440
780 416 610 1215 1156     115543
780 416 610 1235 1180 1225 1168 115888
Table 2.
TempFPMTYAvg TAvg YEM
800 5 189.1 178.2     1.83 16.53
800 5 185.1 176.8 187.1 177.5 1.59 16.31
800 10 187.7 178.6     1.66 16.77
800 10 186.5 181.2 187.1 179.9 1.49 17.27
800 15 184.0 175.1     1.76 16.84
800 15 174.6 173.6 179.3 179.4 1.25 17.09
800 20 180.9 171.8     1.74 16.67
800 20 179.9 172.2 180.4 172 1.66 17.03
825 5 172.0 157.6     1.79 15.51
825 5 170.8 156.1 171.4 156.8 1.70 15.86
825 10 183.1 171.5     1.83 16.59
825 10 185.9 172.1 184.5 171.8 2.08 16.37
825 15 186.3 173.7     2.02 16.63
825 15 184.5 171.3 185.4 172.5 1.99 16.18
825 20 177.9 172.5     1.45 16.51
825 20 186.6 174.4 182.2 173.5 1.92 16.73
850 5 157.6 137.5     2.58 15.87
850 5 151.8 130.2 154.7 133.8 2.47 15.66
850 10 175.1 163.7     1.73 16.33
850 10 176.8 163.2 176.0 163.4 2.00 16.08
850 15 178.6 165.9     1.91 16.25
850 15 173.1 167.6 175.9 166.8 1.40 16.31
850 20 178.9 169.8     1.60 16.53
850 20 178.9 170.4 178.9 170.1 1.56 16.62
Table 2a
TempTemp (°C)FPM (cm/min)T (Mpa)Y (MPa)Avg T (Mpa)Avg Y (Mpa)M (MPa)
800 427 152 1304 1229     113958
800 427 152 1276 1219 1289,8674 1224 112441
800 427 305 1294 1231     115612
800 427 305 1286 1249 1289,8674 1240 119059
800 427 457 1268 1207     116095
800 427 457 1204 1197 1236,0942 1237 1178181
800 427 610 1247 1184     114923
800 427 610 1240 1187 1243,6776 1186 117405
825 441 152 1186 1086     106926
825 441 152 1177 1076 1181,6316 1081 109339
825 441 305 1262 1182     114371
825 441 305 1282 1186 1271,943 1184 112855
825 441 457 1284 1197     114647
825 441 457 1272 1181 1278,1476 1189 111545
825 441 610 1226 1189     113820
825 441 610 1286 1202 1256,0868 1196 115337
850 454 152 1086 948     109408
850 454 152 1047 898 1066,5018 922 107960
850 454 305 1207 1129     112579
850 454 305 1219 1125 1213,344 1126 110856
850 454 457 1231 1144     112028
850 454 457 1193 1155 1212,6546 1150 112441
850 454 610 1233 1171     113958
850 454 610 1233 1175 1233,3366 1173 114578


[0030] Summarizing, it was found that alloys having a minimum 0.2% offset yield strength of at least 1207 MPa (175 ksi), an ultimate tensile strength of at least 1241 MPa (180 ksi), a %elongation at break of at least 1%, and a Young's modulus of at least 110316 MPa (16 million psi) could be obtained. FIG. 2 is a graph showing the 0.2% offset yield strength versus line speed at the different temperatures. The minimum yield strength of at least 1207 MPa (175 ksi) is achieved over a wide temperature range.


Claims

1. A process for improving the yield strength of a wrought copper-nickel-tin alloy, comprising:

performing a first mechanical cold working step on the alloy at a percentage of cold working (%CW) of 50% to 75%; and

heat treating the alloy at a temperature of 393°C (740°F) to 454°C (850°F) for a period of 3 minutes to 14 minutes after the first mechanical cold working step;

wherein the resulting copper-nickel-tin alloy achieves a 0.2% offset yield strength of at least 1207 MPa (175 ksi) and, wherein the alloy consists of 9-15.5 wt% nickel, 6-9 wt% tin, and the remaining balance being copper.


 
2. The process of claim 1, wherein the heat treating step is performed at a temperature of 393°C (740°F) to 427°C (800°F).
 
3. The process of claim 1, wherein the heat treating step is performed by running the alloy in strip form through a furnace at a rate of 152 cm/min (5 ft/min) to 610 cm/min (20 ft/min).
 
4. The process of claim 1, wherein the resulting alloy has a 0.2% offset yield strength of 1207 MPa to 1310 MPa (175 to 190 ksi).
 
5. The process of claim 1, wherein the resulting alloy has an ultimate tensile strength of at least 1241 MPa (180 ksi).
 
6. The process of claim 1, wherein the resulting alloy has a % elongation at break of at least 1%.
 
7. The process of claim 1, wherein the resulting alloy has a Young's modulus of at least 110316 MPa (16 million psi).
 
8. The process of claim 1, wherein the copper-nickel-tin alloy includes from 14.5 wt% to 15.5 wt% nickel, and from 7.5 wt% to 8.5 wt% tin, with the remaining balance being copper.
 


Ansprüche

1. Verfahren zur Erhöhung der Streckgrenze einer Kupfer-Nickel-Zinn-Knetlegierung, umfassend:

Durchführen eines ersten mechanischen Kaltverformungsschrittes an der Legierung bei einem Prozentsatz der Kaltbearbeitung (%CW) von 50% bis 75%; und

Wärmebehandlung der Legierung bei einer Temperatur von 393 °C (740 °F) bis 454 °C (850 °F) für einen Zeitraum von 3 Minuten bis 14 Minuten nach dem ersten mechanischen Kaltverformungsschritt;

wobei die resultierende Kupfer-Nickel-Zinn-Legierung eine 0,2%-Offset-Streckgrenze von zumindest 1207 MPa (175 ksi) erreicht und wobei die Legierung aus 9-15,5 Gew.-% Nickel, 6-9 Gew.-% Zinn und der verbleibende Rest aus Kupfer besteht.


 
2. Verfahren nach Anspruch 1, wobei der Schritt der Wärmebehandlung bei einer Temperatur von 393 °C (740 °F) bis 427 °C (800 °F) durchgeführt wird.
 
3. Verfahren nach Anspruch 1, wobei der Schritt der Wärmebehandlung durchgeführt wird, indem die Legierung in Bandform mit einer Geschwindigkeit von 152 cm/min (5 ft/min) bis 610 cm/min (20 ft/min) durch einen Ofen geführt wird.
 
4. Verfahren nach Anspruch 1, wobei die erhaltene Legierung eine 0,2%-Offset-Streckgrenze von 1207 MPa bis 1310 MPa (175 bis 190 ksi) aufweist.
 
5. Verfahren nach Anspruch 1, wobei die erhaltene Legierung eine Zugfestigkeit von mindestens 1241 MPa (180 ksi) aufweist.
 
6. Verfahren nach Anspruch 1, wobei die erhaltene Legierung eine prozentuale Bruchdehnung von mindestens 1% aufweist.
 
7. Verfahren nach Anspruch 1, wobei die erhaltene Legierung einen Elastizitätsmodul von mindestens 110316 MPa (16 Millionen psi) aufweist.
 
8. Verfahren nach Anspruch 1, wobei die Kupfer-Nickel-Zinn-Legierung 14,5 Gew.-% bis 15,5 Gew.-% Nickel und 7,5 Gew.-% bis 8,5 Gew.-% Zinn enthält, wobei der Rest Kupfer ist.
 


Revendications

1. Procédé d'amélioration de la limite d'élasticité d'un alliage de cuivre-nickel-étain corroyé, comprenant :

la conduite d'une première étape de laminage à froid mécanique sur l'alliage à un pourcentage de laminage à froid (% CW) de 50 % à 75 % ; et

un traitement thermique de l'alliage à une température de 393 °C (740 °F) à 454 °C (850 °F) pendant une durée de 3 minutes à 14 minutes après la première étape de travail à froid mécanique ;

dans lequel l'alliage cuivre-nickel-étain résultant atteint une limite d'élasticité conventionnelle à 0,2 % d'au moins 1207 MPa (175 ksi) et, dans lequel l'alliage est constitué de 9 à 15,5 % en poids de nickel, de 6 à 9 % en poids d'étain et le reste étant du cuivre.


 
2. Procédé selon la revendication 1, dans lequel l'étape de traitement thermique est effectuée à une température de 393 °C (740 °F) à 427 °C (800 °F).
 
3. Procédé selon la revendication 1, dans lequel l'étape de traitement thermique est effectuée en faisant circuler l'alliage sous forme de bande à travers un four à une vitesse de 152 cm/min (5 pieds/min) à 610 cm/min (20 pieds/min).
 
4. Procédé selon la revendication 1, dans lequel l'alliage résultant a une limite d'élasticité conventionnelle à 0,2 % de 1207 MPa à 1310 MPa (175 à 190 ksi).
 
5. Procédé selon la revendication 1, dans lequel l'alliage résultant a une résistance ultime à la traction d'au moins 1241 MPa (180 ksi).
 
6. Procédé selon la revendication 1, dans lequel l'alliage résultant a un allongement à la rupture en % d'au moins 1 %.
 
7. Procédé selon la revendication 1, dans lequel l'alliage résultant a un module d'Young d'au moins 110316 MPa (16 millions psi).
 
8. Procédé selon la revendication 1, dans lequel l'alliage cuivre-nickel-étain comprend de 14,5 % en poids à 15,5 % en poids de nickel, et de 7,5 % en poids à 8,5 % en poids d'étain, le reste étant du cuivre.
 




Drawing











Cited references

REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description




Non-patent literature cited in the description