DE2358510A1 - METHOD OF MANUFACTURING A COPPER ALLOY OF HIGH ELONGATION - Google Patents

Description

■ .j /

u.z .: H 789 M (Dr.Seh / or) 2J. November 1973

309,345-B.

OLIN CORPORATION '

New Haven, Connecticut, V.St.A.

"Process for producing a high elongation copper alloy"

- Priority: November 24, 1972, V.St.A., No. 309

The invention relates to a method of manufacture an annealed, high elongation copper alloy that controls grain growth.

It is common practice to use various grain refining agents add single-phase mixed crystal alloys to during processing from the original casting material to the final, further processed kneading state

.to have a fine-grained material. The addition of "finishing" materials is intended to improve the workability and / or improve the properties. In most cases, the grain-refining agents are used to maintain uniform properties over a range de * · alloy composition and over a

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Range of processing conditions. In many cases, such as copper alloys _; which contain aluminum and a grain-refining element such as cobalt, the grain-refining agents are not over the entire temperature range up to the melting point of the alloys due to dissolution,

Decomposition, implementation or changing solubility or the like. completely stable.

Copper alloys containing grain refiners retain a small grain size over a range of economically expedient annealing temperatures and over a range more economically acceptable Alloy concentrations at. These alloys have relative mechanical properties small changes over these temperature and composition ranges on. There is, of course, one of the economic aspects From a very desirable point of view important property, whereby however, certain limitations in the normally achievable Ductility of the alloy can be generated. In contrast, if a single-phase mixed crystal alloy is heat-treated without grain refiners at higher annealing temperatures, the grain size and the ductility of the alloy while the strength decreases.

It is common practice to anneal at the highest temperature compatible with strength requirements; this gives a material which is unusually high Ductility or ability to change shape during deformation processes, such as stretch forming, is required. The glow

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Temperature is! requiring a hoehpolierte surface in the production of parts also ".begrenzt. Above a certain. grain size occurs namely during Herst el development of an orange skin-like condition which adversely affects the appearance of the polished surface.

Many fine-grained or init kqrnfeinenden means provided -have copper alloys, the undesired egg genschaft _t that.

, every attempt to determine the grain size by means of the fine-tuning V ' ^: .stable'"'"".""; ..: -.. - ..- - ---

Addition given / level also to enlarge ^, zy ßif ^ p We controlled mixed size leads, which consists of very small and unusually large TSorns, this one. Unequal Kprnwaphstupj we.dd ^ rch factors such as .secondary Rer crystallisatiorj, which an uneven gusty @. the effect of the Zvf.eitplias.en -teili.chen on the jvjatri ^ -during the cold deformation and dps subsequent annealing fiii. Material ^ in dera uneven b _? .! z ₅ w jjnrege excessive Kornifa ^ hstuni has taken place, gur Iferstellung is feileil nipht suited the glatt.e surfaces for a ^ -.- i} 3L.anz, b ©] aan.dlunjg, polishing and / or that need to be electroplated or electroplated. In addition to this, there are no different rae.chanic properties ^

De *? The invention is based on the object of providing a method create, niit depi see the ductility ^ on init ko.Knfeinenden " Funded copper alloys improve jjnd

the uneven grain growth can be reduced.

To solve this problem, the input?

mentioned type in principle a final Kai tverf onnunp; on

etv / a
annealed mead ^]] :; between $ / o and $ 22 as well as. • '.nnchlleßei-d oino annealing at high speed or FoT ^ n decrease ' ¹ er · K'?. 'It deformations, which are interrupted by C-lühungen at a relatively high temperature, provided.

The method according to the invention is generally specific to copper gj erungen armendbar, those of about 2 b: i f .; etv; a 9j3 / £ ADu.f.inir'.ü,

et \ · τ β
v; en.jger al. ^c , / l $ zinc ^ and as korni'ejiiendos PJi or,: - :; nt 0.001

up to £ 5 iron, 0.001 bj s 1 fo chromium, 0.001 bir: 3 % zircon: i \ jr ,.

0.00? contains up to 5 °> cobalt or mixtures of these granular elements. Before ^ svjei r, e vroi, the alloys mentioned above also contain about 0.001 bus etv; a 3 ⁽ / j Siliciu. ¹ ;: au f.

The ancestor according to the invention thus creates the possibility of that certain copper alloys provided with grain-refining agents a uniform ductile! did with a controlled. Reach grain size.

The alloys treated by the method according to the invention show a noticeably increased elongation with an appropriately small grain size. ■

The invention also provides a method as mentioned above, ie: «to which the alloy is subjected to a limited, final cold working, to which a final heat transfer; connects at a temperature below about 7.15 ^{0 C.}

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There is also a method such as. Above he guesses / suspects the area of the invention, in which a sequence of decreasing deformations with "inserted" high-temperature annealing 7, * ird.

The invention is explained in more detail below with the aid of a few

explained in more detail:

In general, the method according to the invention makes it possible for certain copper alloys provided with grain-refining agents to achieve improved ductility with a uniformly enlarged grain size. The inventive method is particularly applicable to copper alloys containing from about 2 to about 9 * 5 ../ "aluminum, -less than 1 fo zinc, and a grain-refining element from the group consisting of 0.001 to 5% iron, 0.001 to 1 $> chromium to 1 ⁿ / o zirconium, 0.001 to 5 fo cobalt as well as mixtures containing 0.001 of these elements, the balance being copper. Preferably, the alloy also contains from about 0.001 to about 3 ° silicon; a preferred range for the aluminum additive is from about 2 to about 5 $. It has been found that the inventive method is particularly applicable to the CDA- ' alloy 638, which contains 2.5 to -3.1 % aluminum, 1.5 to Contains 2.1 % silicon, 0.25-0.55 % cobalt and the remainder copper.

It is .desirable * the. In accordance with the invention the aforementioned copper alloys in their further processed "state with improved ductility, such as at least

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hO ^r / o elongation in the Fa] J of the CDA alloy 638, without them being subject to uneven or irregular grain growth.

In a first embodiment of the invention, an alloy within the abovementioned composition areas is produced in the annealed state, the alloy being at a? ¹ temperature below 600 C has been annealed. The annealed alloy is then subjected to a final cold deformation of etv / a 8 bi; :: et-f. 22 %, preferably vci f between 10 and around 20 #. The cold-worked alloy then undergoes a final annealing at a temperature of about 50 to about 715 °

Temperature from about 5t> 0 to about 715 ° C, preferably about about / a approximately

Subjected to 650 MsZYOO ⁰ C.

It has been found that the elongation increases with increasing The final annealing temperature increases. The process described above results in a wrought alloy having a substantially more uniform Grain size less than 0.025 µm, a tensile strength of at least 49.2 kp / mm (70 ksi), a 0.2 ^ yield strength of

at least 21.1 kp / mm (30 ksi) and an elongation of at least 0%. It was possible with the CDA alloy 638 elongations of €; about ^ 5% with a tensile strength of about 52 kp / mm (7 ^ ksi) and

a 0.2 ^ yield strength of etv; a 28.1 kp / mm (40 ksi).

In accordance with preferred developments of the invention the process is carried out in a series of cold deformations, between the annealing processes at a relatively high temperature

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pushed four den.

According to a second, preferred embodiment of the invention, an alloy with a composition within the aforementioned ranges is subjected to cold deformation which is sufficient to ensure recrystallization at a temperature below approximately 600 ° C. In general, cold deformation of the alloy of at least K) % and preferably of at least JO% is required for this. The highest amount of cold deformation is given by the required (final); · .'-: -. 'ST-! N _c ' ret: of the alloy. Then the cold-deformed Lef.ict'it -. 'G is subjected to an intermediate annealing at a temperature of about 400 and about 600 ° C, preferably from about 450 to about 575 ° C. Die-interannealed "alloy is then end-Kuitvc-rforrrar, g from about 8 to about 22%, preferably from about 10 to etv-a 20% untervjorfen. The final kaitverformte alloy is öann an end-Glülumg at a temperature of about 550 to 1s about 715 C, preferably from about 650 to about 700 C.

As accordance with the method in the preceding Ausführungsbeispjel _s takes the strain with the temperature of the final annealing; to. Properties similar to those in the method according to FIG

- stated ■

the previous embodiment / achieved. However, it was found that the temperature of Zwisehenglühung in all respects decisive influence is so far as that · temperatures above about 600 ° C result in non-uniform grain _r growth in the alloy, if the alloy in advance by more than about 22% has been cold worked. . - ..;.,.

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According to a third exemplary embodiment of the invention, an alloy with a composition within the range of Ranges by at least 10 ', 1>, vorzur. ^ Viei <? E um m.nö ^r : r:, tvr> / i'J> 0 '/ :. depending on the desired (final) dimensions kai tvc-worint. P kai tverforii.te alloy is then at a temperature of et ■■: ¹ IQO to otv. ^T a 600 ⁰ C, v0rzu3svKri.se etvza K ^l j0 bär; about i / T '/' C, intermediate annealed.

The intermediate annealed alloy is initially cold worked at a temperature of 25 ° and 40 ° and then at a temperature of about 400 to about 60 ° C., preferably from about 50 ° C. to about 50 ° C. ^r j about i373 ° C, partially annealed. The so zvrisohengeglUhte Legi is then zvischen an end-Kaltverforrnung etvja 8 and about 22 <fo, vorzugsvxeise zv / een about 10 and about 20%, -unterviorfcn. The finally deformed alloy is then finally annealed at a temperature of about 550 to about 715 ° C, preferably from about 650 to about 700 ° C. This embodiment of the invention allows greater flexibility to achieve the required final dimensions in a manner according to the invention; it also generally results in more uniform recrystallization of the alloy and more uniform properties.

V / ie also in the previous exemplary embodiment, the intermediate annealing temperatures have a significant influence here if the alloy has previously undergone cold deformation of more than 22 f _0.

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At λ] lon discussed embodiments of the invention are-the Vorr · ^ the end Keiltverformuiig and the end 0'1.UhUMr hropssohritte critical ,, c to a further processed alloy or a Knetl: \ 3i ervmg with improved elongation without wig} cal \ u'a. ^l \ fms Kornv / f'aihstufn. The processes made possible by the invention are effective. a uniform grain coarsening and essentially uniform grain sizes of below 0.025 π.κι. If the upper limit for the final casting temperature according to the invention is exceeded, uneven or irregular grain growth appears in the alloy. The same applies to the final cold deformation process step, since deformation above 22 % results in the beginning of uneven grain growth. ·

If the invention is also made with reference to specific embodiments management examples has been explained in more detail, it is still possible in addition to the process steps according to the invention further Carry out procedural steps as long as the limits of the Intermediate annealing temperature of the Εηά cold forming and the final annealing be respected. . - -.

The holding times at the corresponding temperature and the heating and cooling rates in the annealing process steps according to the invention are not of decisive importance Influence and may be arbitrarily set in accordance with conventional practice for the types of alloys used v / earth- .. '- ·

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The following discussion aims to clarify the mechanisms those of the crucial nature of the inventors. "^ n procedural measures underlying. Diο explained mechanisms ooj.lon in in no way limit the invention.

For alloys with a low stacking fire energy. If they contain distributed particles of a second phase, such as, dj ο CDA logging 6j53, a cold deformation by *} Ο% leads to a * pronounced I11Ct /] .l2 \ deformation texture or preferred orientation. When the CDA alloy 638 is recrystallized at 50 ° to 600 ° C., it contains newly formed, undeformed, recrystallized grains of very small size. The strong

of grain boundary anchoring effect (pinning, effect) / foinverteilteii CoSi particles of a second phase ensure retention of a fine grain. At higher annealing temperatures above 600 C, the anchoring force is reduced because the CcSi particles aggregate and / or go back into solution.

Under these conditions new recrystallized ones grow Grains with a | no (012) .glow texture or preferred Orientation. Preferably in the ϊΙΙΟί \ 11 ^ texture of the still deformed Areas. Preferred grain growth continues even after recrystallization, since the larger grains the preferred orientation is higher growth rates more different than their smaller neighbors Have orientations. This preferred grain growth leads to the undesirable, irregular grain growth and results a duplex microstructure.

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It vrarde. found that the text uv of the "type hi Oi Π 12) die stable final texture in cold rolled alloys not lower Stack failure teriergy, e.g. of the CDA "alloy 6 ^ 8, is. Ung] e: i ohmic Kornwpehsturn leads to an annealing texture of type 4 3.10 OI2V It is assumed that the development is taking shape Kornvracho turns and the 111G / M 12Vi] ühtextur with the front α:;?: - being of a critical extent to the 4110ί < ] 3 2 \ verfori.n.m £ 3- "texture before final recrystallization is not related to Jon's glow.

The terms texture or preferred orientation refer to the planes of the grains which are parallel to the surface of the metal strip lie.

It was found in connection with the invention, that if the step of final cold working "within the aforementioned deformation ranges, the extent the jUOf OlsN deformation texture below the critical Levels remains, so that no uneven grain growth within the specified temperature ranges during the final annealing occurs. Therefore, with the method according to the invention Uniform grain coarsening without a duplex structure or uneven Corn viaehstum achieved.

The process "according to the invention are described below with reference to further detailed examples. In the examples, the samples were all final annealing and Zwisehenglüh ^un gen for an hour on the relevant

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Temperature 'held. The term Glows up a door relates; r: i- ^ h im In the context of the text at hand, it is more likely to focus on the Ketal] temper .'- door r], s on the

At pie 1 1

Samples of CDA alloy 638 with a composition . 1.9 &'/*> silicon, 2.5 fo aluminum, 0.12 <? O cobalt, the remainder copper. The samples will then correspond to the procedures given in the following table. The mechanical properties and grain sizes of the samples are listed in the table:

Treatment sequence tensile strength 0.2 ^ stretch (fracture) grain

speed, p limit, elongation, size - ,; e, kp / mm (ksi) kp / mm (ksi) ^C , O inrn

A V / V5O ^, G1 575 /

V / V50 ^, G1 575 C 59.1 (84) 40.8 (58) 55 0.005

BY / V45 & G1 575 ° C /
ViV50 ^, Gl 575 ° C /
WVl5 ^, Gl 575 C 54.1 (77) 28.8 (41) 40 0.010

Gl "575 ° C /
G1 575 ° C /
Gl 70O ⁰ C 51.3 (73) 26.7 (38) 45 0.012

VfV = rolling deformation; Gl = annealing

This example shows that a range of elongation, strength properties and uniform grain coarsening, which leads to a suitable small grain size, with the inventive Procedure can be achieved.

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The treatment sequence A corresponds to the conventional treatment in this alloy and does not fall within the scope of the invention Procedure. It is listed for comparison purposes. . ■; -. '*'

The treatment sequences B and G make it clear that gut, if the Step of Encl cold deformation within the scope of the invention Reduction area lies, uniform grain coarsening as well significant improvements in elongation after an end-application can be achieved in a range of annealing temperatures.,

B e i s ρ i e 1 2

Samples of the CDA alloy 6j58 with a composition of 1.9-S -. $ Silicon, 2.5 % aluminum, 0.42 # cobalt, the remainder copper are removed using commercially available equipment to a thickness of 2.Q3 mm (0.08 The specimens are subjected to different final cold deformations and annealed at different final annealing temperatures. The following ratios result: · <

Annealing temperature, ⁰ C; - grain_ mm

600 650 700 750

1.) Samples in the annealed condition, annealed at less than 60O ⁰ C.

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Deformation ' 1.5 $ deformation 50% 0.007 0.005 0.007 '0.005 and 0.030 '' 0.007 O, 060 ⁵ · ' 0.120 ' ⁵ *' o, o8o ³ · '

2.) Duplex micro structure

3.) Grain size after the formation of the high-temperature grain structure.

This example illustrates the decisive influence of the final cold deformation and the upper limit for the final annealing temperature. The results of this example also show that with a final cold working of 15 ^ final annealing temperatures up to 700 ° C can be used without uneven grain growth beginning. With a final cold deformation of 50 % , however, uneven grain growth begins at 65O ⁰ C.

Example?

Samples of CDA alloy 638 with a composition of 1.98 % silicon, 2.5 % aluminum, 0.42 % cobalt, the remainder copper, are produced using commercially available equipment to a thickness of 2.29 trim (0.09 "). The samples are treated according to the following steps, varying the temperature of the intermediate annealing. The results are shown in the following table: ·

Treatment sequence: cold rolling by 45 %, annealing at 575 ° C;

Cold rolling by 30 ? O, intermediate annealing;

Cold rolling by 15 ^, annealing at 700 ° C.

Intermediate tensile strength 0.2 stretching (breaking) - grain annealing, C speed, ₂ limit, elongation, size, kp / mm (ksi) kp / mm ^ (ksi) ^ mm

575 51.5 (75) "26.7 (38) 45 0.010 650 50.6 (72) 25.3 (36) 47.5 4.)

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H.) Mainly 0.005 to Ό, ΟΙΌ ram grains; However, 0.0 ^ 0 mm grains are observed, which indicates an unusually enlarged grain wax turn.

This example clearly illustrates the crucial one Influence of the initial annealing temperature. The example shows dr./3 when the intermediate annealing temperature after cold deformation by at least about 22 $ t / o.ÖO ° C, the beginning exaggerated Grain growth can be expected.

Example ^

Samples of the CDA alloy 638 with a composition of 1.9 # silicon, 2.5 % aluminum, 0.42 μl cobalt, the remainder copper, are obtained using commercially available equipment to a thickness of 2.0 mm (0.08 ") Samples of the alloy are then cold-rolled to four different final deformations, namely 15, 20, 25 and 30 $, and then finally annealed at three annealing stone temperatures, namely 650, 700 and 725 ^O C for one hour., * The samples are evaluated metallographically _{; to} find out -what degree of deformation-temperature-combinations produce uniform grain coarsening. The ratios listed in the following table were obtained:

Cold deformation, % ' ■ grain structure at _r an end

O,

Annealing temperature, C

650 700 725

15 ■ 8.) 8.) 7.)

25 6.) 7.) 7.)

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5.) Samples in the annealed condition, annealed at less than 60O ¹ C. 6.) Almost completely uniform structure, one or two, oi

scattered, large grains.
7.) Duplex grain structure.
8.) Uniform grain structure.

These results make it clear that end deformations within of the areas according to the invention lead to a uniform grain structure, while deformations outside the

around

suitable area., for example v7ei.se/2i} ^r / o, lead to uneven grain growth and a resulting duplex grain structure. The results make it further clear that at final annealing temperatures outside the range given in the invention, ie above 715 ° C., a uniform grain structure cannot be ensured at any of the listed degrees of cold deformation.

The above examples clearly illustrate the crucial one Influence of the intermediate annealing temperature, the final cold deformation and the final annealing temperature as indicated by the methods of the invention.

The invention has been completed using a single end cold working and a single final anneal. It is understood, however, that a number of cold deformations and annealing can be used within the ranges of final cold working and final annealing without it being in the alloy uneven grain growth occurs. So there is also one

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• 7-

Series of several deformations and anneals within the ranges · the end deformation and the end annealing to the scope of the invention. . . \ · "

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Claims (10)

Patent claims: ■ 1 »process for the production of an annealed copper alloy with high elongation, box in which the grain wax is controlled turn, characterized in that an alloy with about 2 to about 9 * 5 fo aluminum, with less than about 1 fo zinc, with - than grain refiner serving from about 0.001 to about 5 % iron, from about 0.001 to about 1 % chromium, from about 0.001 to about. 1 % zirconium, 0.001 to 5 fo Koba.lt or mixtures of these elements, the remainder copper is used j that the alloy is subjected to a final cold forming of about 8 to about 22 % ; and that then the alloy at a temperature between about 550 and about 715 ° C is final annealed. 2. The method according to claim 1, characterized in that an alloy is used which additionally contains about 0.001 to about 0.001 to about 3 % silicon and in which the aluminum content is between about 2 and about 2 to about 5 fo . 3. Method according to claim 1 or 2, characterized in that an alloy is used which contains 2 _S 5 to 3 * 1 % aluminum, 1.5 to 2, -1 % silicon, 0.25 to 0.55 % cobalt, The remainder contains copper. 4. The method according to any one of claims 1 to ^, characterized in that that the alloy undergoes final cold working between 409823/0830 etvra is subject to 10 and about $ 20. 5. The method according to any one of claims 1 to k, d'-characterized in that the alloy is finally annealed at a temperature of about 650 Ms about TOO C. 6. The method according to any one of claims 1 to 5 *, characterized in that before the final Kai tver deformation, the alloy is subjected to a first cold deformation by at least 10 ^c fo in such a way / that it recrystallizes at a temperature of less than about 60Ö ° C , and that the alloy is then also subjected to a first intermediate annealing at a temperature of about 400 to about 600 ° C. before the final cold working. 7. The method according to claim 6 _S, characterized in that the first cold deformation is carried out by at least J50 % and that the temperature of the first intermediate annealing is selected between about 450 and about 575 ° C xcLrd. 8. The method according to claim 6 "or J ,. Characterized in that between the first intermediate annealing and the final cold-working, the alloy is cold-worked by about 25 to about 40 % and then at a temperature between about 400 and et \\ ^T a 600 ° C one more intermediate annealing. 9. The method according to claim 8, characterized in that further intermediate annealing at a temperature of about "450" Ä09823 / Ö83Ö BAD ORKStNAL to about, 575 ⁰ C is carried out. 10. The method according to any one of claims 6 to 9 *, characterized in that the cold deformation (s) before the final cold deformation by about 10 to etx-generally 20 % is carried out and that the annealing temperature (s) before the end Annealing between approximately 650 and approximately 700 0 is (are) selected. BADORONAL 409823/0830