JP2017532436A - Electrical connection member - Google Patents

Abstract

An electrical connection member containing a copper-zinc alloy. The copper-zinc alloy comprises (by weight) Zn 28.0-36.0%, Si 0.5-1.5%, Mn 1.5-2.5%, Ni 0.2-1.0. %, Al 0.5 to 1.5%, Fe 0.1 to 1.0%, optionally further Pb up to 0.1%, optionally further P up to 0.1%, optionally further Up to 0.08% S, the balance is Cu and inevitable impurities. According to the present invention, an iron-nickel-manganese-containing mixed silicide is present in the matrix. The structure consists of an alpha matrix, which contains 5 to 45 volume% beta phase and up to 20 volume% iron-nickel-manganese containing mixed silicide inclusions. Furthermore, the iron-nickel-manganese-containing mixed silicide having a columnar shape and the iron-nickel enriched mixed silicide having a spherical shape are present in the structure.

Description

  The invention relates to an electrical connection member comprising a copper-zinc alloy according to the preamble of claim 1.

  Many new automotive applications for safety, comfort and performance are realized only through the proper use of electronic functions and electronic components. Due to the increasing demand for connectors and the materials used therefor, in recent years there has been a trend towards high performance copper alloys. These precipitation-hardening copper materials are excellent in high mechanical strength, high conductivity, and good deformability. Starting with the first generation of Cu high performance alloys, such as CuNi3SiMg, which has a conductivity slightly above 20 MS / m, the combination of properties of high strength and high conductivity had to be further optimized.

  One step in this direction was first to develop a precipitation hardened copper alloy based on the CuCrAgFeTiSi system, for example having a strength of 46 MS / m and up to 610 MPa. Another major advantage of this alloy is that the stress relaxation resistance of the material in use at temperatures as high as 200 ° C. is very good. This alloy mold can cover applications in the fields of automobiles, industrial electronics and telecommunications.

  Furthermore, a bronze material having a fine structure with a maximum particle size of 3 μm is used. As a result, an essentially high mechanical strength can be obtained simultaneously with greatly improved molding properties. As a result of the clearly improved formability, the operator can correspondingly achieve a narrow bending radius. Similarly, the improved flexibility results in much less roughness in the molding area than when using standard bronze. Thus, subsequent coatings can be performed with a thinner film thickness, thereby achieving significant cost savings during post-processing. The conductivity is the same as standard bronze and is about 7.5 to 12 MS / m.

  Other precipitation hardened CuNi1CoSi alloys with Ni-Co mixed silicides are also very suitable for efficiently miniaturizing connectors. This material is high in strength, has a relatively good conductivity of 29 MS / m and thermal conductivity, and is easy to process.

  These described materials are especially suitable for processing in automatic press / bending machines, but can only be machined with great expense.

Other copper materials in the form of rods and wires that are very suitable for connector sockets and pins produced by cutting are also made of inexpensive brass materials with alloys of CuZn37Pb0.5, CuZn35Pb1, CuZn35Pb2, CuZn37Pb2, CuZn36Pb3 and CuZn39Pb3 Known in material construction, these are used for applications that are demanding in the manufacture of round connectors.

  In these cases, materials having a combination of high conductivity, high mechanical strength and both of these properties are used due to technical requirements. Therefore, CuPb1P is another easy-to-cut material for automatic machines having a high conductivity of about 50 MS / m at the same time. This is particularly suitable for connectors and other electronic applications.

  In addition to the solid solution hardening type alloy, the alloy range is completed by another precipitation hardening type material. This includes, for example, CuNi1Pb1P and CuNiPb0.5P as low alloy copper materials with high strength, good conductivity of at least 32 MS / m and good machinability. This material is particularly suitable for electrical outlets manufactured by cutting in electrical and electronic engineering due to its Pb content.

  Even with multi-component tin bronze CuSn4Zn4Pb4P having a tin content, a zinc content, and a lead content of 4%, high strength with appropriate spring characteristics can be set. This tin bronze is easy to cold work and can be cut wonderfully. A special field of use is elastic electronic contacts.

  In developing an alloy, various environmental regulations and material restrictions must always be taken into consideration. This creates another development possibility for alternative or additional alloys that excel in the combination of properties suitable for the connector. In this case, in addition to the physical properties, particularly, good workability plays an important role.

  The present invention is to develop an electrical connection member made of a copper alloy containing less lead or containing no lead.

  The invention is indicated by the features of claim 1. Other dependent claims show preferred forms and developments of the invention.

The present invention includes technical teachings on the structure of electrical connection members comprising a copper-zinc alloy. This copper-zinc alloy is (by weight)
Zn 28.0 to 36.0%,
Si 0.5 to 1.5%,
Mn 1.5 to 2.5%,
Ni 0.2 to 1.0%,
Al 0.5 to 1.5%,
Fe 0.1 to 1.0%,
Optionally further Pb up to 0.1%,
Optionally further P up to 0.1%,
Optionally further up to S 0.08%,
It consists of the balance Cu and inevitable impurities.
According to the present invention, an iron-nickel-manganese-containing mixed silicide is present in the matrix. The structure consists of an alpha matrix, which contains 5 to 45 volume% beta phase and up to 20 volume% iron-nickel-manganese containing mixed silicide inclusions. Furthermore, the iron-nickel-manganese-containing mixed silicide having a columnar shape and the iron-nickel enriched mixed silicide having a spherical shape are present in the structure.

  Surprisingly, it has been found that the alloy composition according to the invention is suitable for electrical connection members. Heretofore, the use of such alloys has been scheduled only for the use of sliding members in internal combustion engines, transmissions or hydraulic units, according to the Applicant's German Patent Application Publication No. 102007029991. The contents of this publication are fully incorporated herein. With such different applications, other objectives of the combination of properties optimized for a particular application purpose are pursued. For engine applications, it is a combination of properties consisting of increasing the strength, temperature stability of the structure and combined wear resistance as well as sufficient toughness properties.

  In contrast, the present invention provides an electrical connection member comprising a copper-zinc alloy intercalated with an iron-nickel-manganese-containing mixed silicide, which can be produced by a continuous or semi-continuous continuous casting method. Departs from. Due to the formation of mixed silicides and formation of the structure, the copper-zinc alloy has a very high conductivity in this material group.

  Moreover, although the said alloy has a high hardness value and a strength value, the ductility represented by the breaking elongation value in the tensile test is guaranteed to a necessary level. This combination of properties proves that the subject of the invention is particularly suitable as an electrical connection member, such as, for example, round connectors, plug devices, electrical terminals, and optionally those with screw joints.

  In the manufacturing process that precedes the casting of an alloy, first, an initial precipitation of a mixed silicide containing a large amount of iron and nickel is performed. These precipitates can be further grown to form iron-nickel-manganese-containing mixed silicides that are often columnar and of considerable size. Furthermore, a significant proportion remains rather in a small spherical form and exists in a finely dispersed manner in the matrix. This finely dispersed silicide is regarded as the basis for stabilizing the β phase. In particular, the alloy has high ductility during cold working. This is particularly important in the case of pressure bonding in which the material is usually strongly plastically deformed in the electrical connection member. Therefore, flanging, crimping or bending can be performed under almost any degree of deformation without causing cracks in the material.

  In particular, the material is also suitable for an electrical connection member manufactured by cutting. Good machinability is already obtained with 5% by volume of β phase. For higher contents, up to 45% by volume of the β phase also improves the formation of the cut pieces during the cutting process, desirably by forming short cut pieces. When the β phase content is less than 5% by volume, the machinability when used as a material for an automatic machine for increasing the machining rate is no longer satisfactory. It is clear that the β phase content exceeding 45% by volume deteriorates the toughness of the material and the temperature stability of the structure. The final state of the alloy from each manufacturing method becomes a β phase interspersed in an island shape in the structure made of the α matrix. Such islands consisting of β-phase are particularly advantageous for the machinability and corrosion resistance of the alloy.

  However, a particularly high surface quality of the machined surface is obtained, in particular with a 10 to 25 volume% β-phase content. Even in the 5 to 45 vol% β phase volume range mentioned above, relatively little tool wear occurs, so that the tool has a correspondingly long life, thereby reducing tool costs. If the content of the iron-nickel-manganese-containing mixed silicide exceeds 20% by volume, the increase in hardness becomes large, so that the material impairs the balance of advantageous property combinations.

The stress relaxation properties of the material should also be particularly emphasized so that the elasticity of the electrical connection member remains maintained.

  The particular advantage of the alloys according to the invention is therefore based on a combination of properties optimized for the intended use, in the form of increased strength, structural temperature stability and electrical conductivity, as well as sufficient toughness properties. .

  Furthermore, the claimed material solutions take into account the need for an environmentally friendly lead-free alternative alloy based on the lead content replaced with conventional alloys. In addition, this material is expected to be used in special applications where the required degree of plasticity is important despite the high demands on hardness and strength.

In a preferred embodiment of the present invention, the copper-zinc alloy is
Zn 30.0 to 36.0%,
Si 0.6 to 1.1%,
Mn 1.5 to 2.2%,
Ni 0.2 to 0.7%,
Al 0.5 to 1.0%,
Fe 0.3 to 0.5%
May be included.
A particularly suitable alloy composition is selected when the limit value is in a narrower range. This further improves the toughness properties and conductivity, possibly by finishing with stress relief annealing. Advantageously, the final stress relief annealing is performed at 300 ° C. to 400 ° C. for 3 to 4 hours.

  In another preferred embodiment of the present invention, the copper-zinc alloy may contain 33.5 to 36.0% Zn. Thus, even if the zinc content is higher, the toughness characteristics and good conductivity required for the electrical connecting member are still realized. By increasing the zinc content as much as possible, the content of other elements, in particular the copper content, is reduced accordingly. As a result, this alloy has a lower metal price by increasing the inexpensive zinc content accordingly.

  Suitably, the conductivity of the alloy may be at least 5.8 MS / m. A particularly advantageous conductivity is from at least 10 MS / m to over 13 MS / m. These values are not obtained with comparable materials such as lead-containing brass. Even values exceeding 13 MS / m can be set by appropriate post-processing steps.

  Preferably, the structure consisting of an alpha matrix containing inclusions of 5 to 45% by volume of beta phase and 20% by volume of iron-nickel-manganese containing mixed silicides is at least one hot working step. And / or may be formed after post-processing including cold working steps and optionally other annealing steps. Due to the different inclusion sizes of β inclusions and the hard phase in the α matrix, this alloy guarantees a suitable temperature stability of the structure as well as toughness properties sufficient to produce a connecting member.

For post-processing, the alloy may preferably undergo the following steps during subsequent processing:
An extrusion or hot rolling process in the temperature range from −600 to 800 ° C.,
At least one cold working step, preferably a drawing or cold rolling step.

Also, in an advantageous embodiment of the invention, the alloy may undergo the following steps during subsequent processing:
An extrusion or hot rolling process in the temperature range from −600 to 800 ° C.,
At least one cold working step, preferably a drawing or cold rolling step, and at least one annealing step in the temperature range from 250 to 700 ° C., preferably from 20 minutes to 5 hours, Process that combines. Cold working process by drawing and one or more raw materials in the shape of round wire, deformed wire, round bar, deformed bar, hollow bar and tube in the temperature range from 250 to 700 ° C By combining with the annealing step, a fine distribution of a heterogeneous structure can be produced. In this way, a need for improved conductivity is met.

  The relationship between the content and distribution of the β phase content and the temperature stability of the structure is also of particular interest. However, since this body-centered cubic crystal type has an indispensable function of increasing the strength in the copper-zinc alloy, minimization of the β content has never been the focus of attention. The structure of the copper-zinc alloy so that in addition to high strength, the production sequence of extrusion or hot rolling / stretching or cold rolling / intermediate annealing has more sufficient temperature stability, ductility and good conductivity. Can be modified in its phase distribution.

  In an advantageous embodiment, in the post-processing, the forming process can be followed by at least one stress relief annealing step in the temperature range from 250 to 450 ° C. and preferably with an annealing time of 2 to 5 hours. .

  In the manufacturing process, there is a need to reduce the height of the internal stress by one or more stress relief annealing steps. The decrease in internal stress guarantees sufficient temperature stability of the structure and is sufficient for the round wire, deformed wire, round bar, deformed bar, hollow bar and tube as the predecessor product of the electrical connection member. It is also important to ensure straightness.

    Other embodiments of the invention are described in more detail in the table. This is the embodiment that was considered the best according to the test. However, other embodiments different from this are equally suitable for obtaining the advantages of the present invention within the framework of the present invention.

  The copper-zinc alloy cast bolt according to the present invention was manufactured by continuous casting or die casting. The chemical composition of the continuous casting of alloy 1 and the chemical composition of the mold castings of alloys 2 and 3 can be read from Table 1.

Manufacturing order 1:
・ Casting bolt made of alloy 1 is extruded at a temperature of 670 to 770 ° C. to form a tube material. ・ Cold processing / intermediate annealing (630 to 700 ° C./50 minutes to 3 hours) / adjustment / stress relief annealing (300 ~ 400 ° C / 3 hours)

  After the production is finished, the structural property values, conductivity and mechanical properties of the pipe material having dimensions of (30.1 × 24.7) mm are at the levels shown in the numerical values of Table 2.

Manufacturing order 2:
-Cast bolt made of alloy 1 is extruded at a temperature of 650-750 ° C to form a round bar- Cold work / annealing (630-720 ° C / 50 minutes to 4 hours) / adjustment / stress relief annealing (300-450 ° C / 2-4 hours) combination

  After the production is finished, the structural property values, conductivity and mechanical properties of the round bars having diameters of 13.40 mm, 16.35 mm and 45.50 mm are at the levels indicated in the numerical values in Table 3. is there.

Manufacturing order 3:
-A cast block made of alloys 2 and 3 is hot-rolled into a rolled plate at a temperature of 650-730 ° C.-Stress-relief annealing (300) when the plate is cold-rolled at a degree of deformation of 15 to 25%. Additional milling of the surface, optionally further between each step with ~ 450 ° C / 2-4 hours)

Manufacturing order 4:
-A cast block made of alloys 2 and 3 is hot-rolled into a rolled sheet at a temperature of 650-730 ° C-Annealing (650 ° C / 3 hours) and optionally stress-relieving annealing (300-450 ° C / 2) Additional and optionally further milling of the surface between each step in combination with cold rolling of the plate at a degree of deformation of 15 to 25% with ~ 4 hours)

Manufacturing order 5:
-A cast block made of alloys 2 and 3 is hot rolled at a temperature of 650-730 ° C to make a rolled plate-Cold rolling / annealing of the plate at a degree of deformation of 15-65% (630-720 ° C) / 50 minutes to 4 hours) in addition between each step, optionally further milling the surface

  In particular, the characteristic value for the conductivity can be further increased in the form of alloys 2 and 3 produced according to production sequence 5, by an additional stress relief annealing at a temperature of 250 to 450 ° C.

  It should be emphasized with respect to the above examples that in all five production sequences, the β content is between 5 and 20%. Other tests have shown that the β content is preferably 5-30%. The formation of the β phase intervening in the structure of the α matrix, which is island-like in the final state of manufacture, may appear in a slightly different way in this case. If the β-phase content is further reduced, islands that are isolated from each other are formed, and in extreme cases, they may form a kind of packing for the α-matrix crystallites.

Claims (10)

(In weight%)
Zn 28.0 to 36.0%,
Si 0.5 to 1.5%,
Mn 1.5 to 2.5%,
Ni 0.2 to 1.0%,
Al 0.5 to 1.5%,
Fe 0.1 to 1.0%,
Optionally further Pb up to 0.1%,
Optionally further P up to 0.1%,
Optionally further up to S 0.08%,
In an electrical connection member comprising a copper-zinc alloy composed of the balance Cu and inevitable impurities,
-An iron-nickel-manganese-containing mixed silicide is present in the matrix,
The structure consists of an α matrix, which contains 5 to 45% by volume of β phase and up to 20% by volume of iron-nickel-manganese containing mixed silicide inclusions;
An electrical connection member characterized in that the iron-nickel-manganese-containing mixed silicide having a columnar shape and the iron-nickel-rich mixed silicide having a spherical shape are present in the structure. The electrical connection member according to claim 1, characterized by:
Zn 30.0 to 36.0%,
Si 0.6 to 1.1%,
Mn 1.5 to 2.2%,
Ni 0.2 to 0.7%,
Al 0.5 to 1.0%,
Fe 0.3 to 0.5%. The electrical connection member according to claim 2, characterized by:
Zn 33.5 to 36.0%.   The electrical connection member according to any one of claims 1 to 3, wherein the electrical conductivity of the alloy is at least 5.8 MS / m or more.   The electrical connection member according to claim 4, wherein the alloy has an electrical conductivity of at least 10 MS / m or more.   The electrical connection member according to claim 5, wherein the electrical conductivity of the alloy is at least 13 MS / m or more.   A structure consisting of an α matrix containing inclusions of 5 to 45% by volume of β phase and 20% by volume of iron-nickel-manganese containing mixed silicides is at least one hot working step and / or cold. The electrical connection member made of a copper-zinc alloy according to any one of claims 1 to 6, wherein the electrical connection member is formed after post-processing including an inter-working step and optionally another annealing step. The electrical connection member comprising the copper-zinc alloy according to claim 7, wherein the alloy has undergone the following steps during subsequent processing:
An extrusion or hot rolling process in the temperature range from −600 to 800 ° C.,
At least one cold working step; The electrical connection member comprising the copper-zinc alloy according to claim 7, wherein the alloy has undergone the following steps during subsequent processing:
An extrusion or hot rolling process in the temperature range from −600 to 800 ° C.,
A combination of at least one cold working step and at least one annealing step in the temperature range from 250 to 700 ° C.   10. The electricity comprising a copper-zinc alloy according to claim 8, wherein in the post-processing, the forming process is followed by at least one stress relief annealing process in a temperature range of 250 to 450 ° C. 10. Connection member.