TWI651422B - Electrical connector - Google Patents

Abstract

An electrical connector containing a copper-zinc alloy. The copper-zinc alloy is composed of the following (in wt%): 28.0 to 36.0% Zn, 0.5 to 1.5% Si, 1.5 to 2.5% Mn, 0.2 to 1.0% Ni, 0.5 to 1.5% Al, 0.1 To 1.0% Fe, optionally further containing a maximum of 0.1% Pb, optionally further containing a maximum of 0.1% P, optionally further containing no more than 0.08% S, residual amounts of Cu and inevitable impurities.

According to the present invention, a mixed silicide containing iron nickel manganese is embedded in the matrix. The structure consists of an alpha matrix in which the intercalation contains 5 to 45 vol% of the β phase and no more than 20 vol% of the iron-nickel-manganese-containing mixed silicide. In addition, in this configuration, the iron-nickel-manganese-containing mixed silicide is in a columnar form and the iron-nickel-rich mixed silicide is in a spherical form.

Description

Electrical connection Field of invention

The invention relates to an electrical connector comprising a copper-zinc alloy as described in the preamble of claim 1.

Background of the invention

Countless new automotive applications in terms of safety, comfort and performance can only be achieved through targeted use of electronic functions and components. Due to the increasing requirements for plug connectors and their materials, there has been a trend to use copper-high-performance alloys in recent years. These precipitation-hardened copper materials are characterized by high mechanical strength, high conductivity, and easy deformation. Taking the first generation of Cu-HP alloys (such as CuNi3SiMg with a conductivity higher than about 20MS / m) as the starting point, it is necessary to further optimize the combination of characteristics of high strength and high conductivity.

An optimization approach is to develop a precipitation-hardened copper alloy based on a system CuCrAgFeTiSi of 46 MS / m and a strength not exceeding 610 MPa. Another major advantage of this alloy is that the material has excellent relaxation strength at high temperatures not exceeding 200 ° C. This alloy type can be used in the fields of automotive, industrial electronic equipment and telecommunications.

In addition, certain types of bronze materials are also used, which are characterized by a fine structure with a maximum particle size of 3 μm. This material significantly improves processing characteristics while Significantly improve mechanical strength. With significantly improved workability, processors can achieve narrower bending radii. With improved bendability, the roughness in the deformed area is much smaller than when using standard bronze. In this way, the thickness of the subsequent coating can be reduced, and the cost during subsequent processing can be greatly reduced. The conductivity of this material is the same as that of standard bronze, about 7.5 to 12 MS / m.

Another precipitation-hardened CuNi1CoSi alloy with Ni-Co mixed silicide is also very suitable for miniaturizing plug connectors to reduce costs. This material is high strength, has good electrical conductivity (29MS / m) and thermal conductivity, and is easy to handle.

The above materials are mainly suitable for processing on an automatic punching machine / automatic bending machine, and it is difficult to perform cutting processing on them.

In the material combination of inexpensive brass materials including the alloys CuZn37Pb0.5, CuZn35Pb1, CuZn35Pb2, CuZn37Pb2, CuZn36Pb3, and CuZn39Pb3, more copper materials in the form of rods or wires are also disclosed, which are very suitable for cutting The copper materials can be used to manufacture sockets and pins of plug-in connectors, and these copper materials can be used in places with higher requirements in manufacturing rotary plug-in connectors.

Under the foregoing circumstances, depending on the specific technical requirements, materials with high electrical conductivity, high mechanical strength, and a combination of these two characteristics need to be used. Therefore, CuPb1P is also a material for automatic equipment with good cutting effects, and it also has high electrical conductivity, about 50MS / m. This material is especially suitable for plug-in connectors and other electronic applications.

In addition to mixed crystal hardened alloys, the alloy range also includes more precipitation hardened materials. For example, CuNi1Pb1P and CuNiPb0.5P are included in the above range, and these are low-alloy copper materials having high strength, good conductivity (at least 32MS / m), and good machinability. This material is particularly suitable for electrical and Plug-in contacts made by cutting in electronic equipment.

The use of multiple tin bronze CuSn4Zn4Pb4P can also achieve higher strength and corresponding elastic characteristics, each with 4% tin, zinc and lead ratios. The tin bronze has good cold workability and is easy to cut. It is particularly suitable for flexible electronic device contacts.

As far as current alloy research and development work is concerned, it is always necessary to take into account various environmental direct factors and material restrictions. Therefore, there is still research and development potential in terms of alternative or complementary alloys with suitable combinations of properties for plug connectors. In addition to physical properties, good processability is also important.

Summary of invention

The object of the present invention is to improve an electrical connector made of a low-lead or lead-free copper alloy.

The invention is given by the features of claim 1. More back-referenced claims give advantageous construction schemes and improvement schemes of the present invention.

The present invention includes a technical principle for constructing an electrical connection member containing a copper-zinc alloy. The copper-zinc alloy is composed of the following (in wt%): 28.0 to 36.0% Zn, 0.5 to 1.5% Si, 1.5 to 2.5% Mn, 0.2 to 1.0% Ni, 0.5 to 1.5% Al, 0.1 Up to 1.0% Fe, optionally with a maximum of 0.1% Pb, and optionally with a maximum of 0.1% P, Optionally, it does not contain more than 0.08% of S, residual Cu, and unavoidable impurities.

According to the present invention, a mixed silicide containing iron nickel manganese is embedded in the matrix. The structure consists of an alpha matrix in which the intercalation contains 5 to 45 vol% of the β phase and no more than 20 vol% of the iron-nickel-manganese-containing mixed silicide. In addition, in this configuration, the iron-nickel-manganese-containing mixed silicides are in a columnar form and on the iron-nickel-rich mixed silicides are in a spherical form.

Practice has unexpectedly shown that the alloy composition of the present invention is suitable for electrical connections. According to German Patent Application Publication DE 10 2007 029 991 A1 of the inventor, such alloys have hitherto only been used for sliding elements of internal combustion engines, transmissions or hydraulic equipment. The entire contents of this patent application publication are incorporated in the description of the present invention. The goal of the differentiated application in this case is not a dedicated and optimized combination of features. Instead, a combination of characteristics is obtained in motor applications, which maintains sufficient toughness characteristics while improving strength, temperature resistance and complex abrasion resistance.

The present invention is based on the following idea: to provide a copper-zinc alloy embedded with a mixed silicide containing iron, nickel, and manganese, which can be specifically made by a continuous or semi-continuous continuous casting method. After adopting the mixed silicide formation and construction scheme, the copper-zinc alloy has extremely high electrical conductivity in terms of its material category.

This alloy has a high degree of hardness and strength while it has the necessary degree of ductility (ie, the elongation at break in a tensile test). Inventive objects with this combination of characteristics are particularly suitable for electrical connectors, such as rotary plug connectors, plug devices, and electrical clamps, and optionally can be combined with screw connectors.

In the foregoing manufacturing steps for casting the alloy, first, iron-rich precipitates And nickel-rich mixed silicide. The precipitates can be grown in the process of further growing into a siliceous iron-nickel-manganese-containing mixed silicide having a considerable size and usually a columnar shape. In addition, a considerable portion remains small, spherical and dispersed in the matrix. The dispersed silicides are considered as a substrate in order to stabilize the β phase. In particular, the alloy has high ductility during cold working. This point is particularly important when crimping electrical connectors, because the material needs to withstand strong plastic deformation during the crimping process. That is, the material can be crimped, pressed, or folded with almost any degree of processing without crack formation.

This material is also particularly suitable for electrical connections made by cutting. With 5 vol% β phase, good machinability can be obtained. When the β phase content is higher but not more than 45 vol%, the desired short chips are also formed, thereby improving chip formation in cutting operations. When the β-comparative example is less than 5 vol%, when used as a material for automatic equipment, the machinability causes a high cutting rate, and the effect is not good. When the β phase content is greater than 45 vol%, the toughness of the material and the temperature resistance of the structure are deteriorated. The final state of the alloy produced by the corresponding manufacturing method produces a certain β phase, which is island-like embedded in a structure composed of an α matrix. This type of island composed of β phase is particularly beneficial to the machinability and corrosion resistance of the alloy.

In particular, a β-comparison of 10 to 25 vol% can achieve an excellent surface quality of a cut surface. Within the aforementioned volume range of 5 to 45 vol% β phase, relatively small tool wear is also achieved, thereby extending tool life and reducing tool costs. The proportion of mixed silicides containing iron, nickel and manganese exceeding 20 vol% will increase the hardness increase, making it difficult to properly combine the favorable characteristics of the materials.

The material also has excellent relaxation strength, so that the elasticity of the electrical connection can be maintained.

In view of this, the main advantages of the alloy of the present invention are based on a The combination of properties optimized for use, while maintaining sufficient toughness characteristics, improves strength, temperature resistance and electrical conductivity of the structure. Based on the relative lead content of relatively common alloys, the material solution of the present invention also takes into account the necessity of environmentally friendly lead-free alloy solutions. This material can also be tailored for special applications that require high plasticity in addition to high requirements on hardness and strength.

According to an advantageous design solution of the present invention, the copper-zinc alloy may contain 30.0 to 36.0% of Zn, 0.6 to 1.1% of Si, 1.5 to 2.2% of Mn, 0.2 to 0.7% of Ni, and 0.5 to 1.0% of Al, 0.3 to 0.5% Fe.

By narrowing the range, a particularly advantageous alloy composition is selected. As a result, the toughness characteristics and electrical conductivity are further improved, and the final stress relief annealing is also improved, as the case may be. The final stress relief annealing is preferably performed at 300 ° C to 400 ° C for 3 to 4 hours.

According to another advantageous design solution of the present invention, the copper-zinc alloy may contain 33.5 to 36.0% of Zn. Such zinc content can still achieve the toughness characteristics and good electrical conductivity required for electrical connections. Increasing the zinc content as much as possible will reduce the proportion of other elements, especially the proportion of copper. In this case, the alloy would have a correspondingly lower metal price due to the higher proportion of cheap zinc.

The electrical conductivity of the alloy may preferably be at least 5.8 MS / m. A particularly preferred conductivity is at least 10 MS / m to 13 MS / m or more. This cannot be achieved with comparable materials, such as leaded brass. It can even be achieved with suitable subsequent processing steps13 MS / m or more.

Advantageously, the structure comprising an alpha matrix, in which the embedded phase contains 5 to 45 vol% beta phase and not more than 20 vol% of iron-nickel-manganese-containing mixed silicide, the structure can be constructed in a subsequent processing, the Subsequent processing includes at least one hot working and / or cold working and optionally further annealing steps. In the α matrix, different size distributions are used for the β-inlay and the hard phase, so that the alloy achieves favorable structural temperature resistance and has toughness characteristics sufficient to manufacture the connection.

When carrying out the subsequent processing, the alloy may preferably undergo the following steps during its subsequent processing:-extrusion or hot rolling in a temperature range of 600 to 800 ° C,-preferably by drawing or cold rolling At least one cold working is performed.

According to a preferred design of the present invention, the alloy may also undergo the following steps during its subsequent processing:-extrusion or hot rolling in the temperature range of 600 to 800 ° C,-preferably by stretching or cold At least one cold working performed by rolling is combined with one of at least one annealing performed in a temperature range of 250 to 700 ° C. The annealing duration is preferably 20 minutes to 5 hours.

Through cold working performed by drawing, and one or more of the starting materials in the form of round wires, shaped wires, round rods, shaped rods, hollow rods and pipe fittings in a temperature range of 250 to 700 ° C Annealing and combining together can achieve the dispersed distribution of the heterostructure. This meets the requirements for improved conductivity.

The correlation between the size and distribution of the β-phase ratio and the temperature resistance of the structure is also significant. This crystalline method with a cubic space in the center assumes an indispensable function of increasing the strength in the copper-zinc alloy, so reducing the β content is not only concentrated in Outstanding position. Through the process of extrusion forming or hot rolling / drawing or cold rolling / intermediate annealing, the phase distribution of the structure of the copper-zinc alloy can be changed, so that the structure has sufficient temperature resistance, ductility and Good electrical conductivity.

According to a preferred design solution, in the subsequent processing, after the processing is completed, at least one stress relief annealing is performed in a temperature range of 250 ° C. to 450 ° C., and the annealing duration is preferably 2 to 5 hours.

During the manufacturing process, one or more stress relief annealings are required to reduce the self-stress. In order to ensure that the structure has sufficient temperature resistance and to ensure that the round wires, shaped wires, round rods, shaped rods, hollow rods and pipe fittings used as the starting products of electrical connectors have sufficient flatness, reduce their own Stress is also important.

Detailed description of the preferred embodiment

The following describes several embodiments of the present invention in detail with reference to the drawings. Here is a description of a preferred embodiment. However, in the present invention, other embodiments that are different from this embodiment are also suitable for achieving the advantages of the invention.

Here, the slab of the copper-zinc alloy of the present invention is produced by extrusion molding or chill casting. See Table 1 for the chemical composition of the extrusion molding of Alloy 1 and the cold-hard casting of Alloys 2 and 3.

Operation 1

挤压 Extrusion of slab made of alloy 1 into pipe fittings under the temperature of 670-770 ℃

组合 Cold working / intermediate annealing (630-700 ℃ / 50 minutes-3 hours) / orientation / stress relief annealing (300-400 ℃ / 3 hours)

After manufacturing, the structural property values, electrical conductivity, and mechanical properties of these 30.1x24.7 pipe fittings are at the levels shown in Table 2.

Operation 2

挤压 Extrusion of a slab made of alloy 1 into a round rod at a temperature of 650-750 ° C

组合 Cold working / annealing (630-720 ℃ / 50 minutes-4 hours) / orientation / stress relief annealing (300-450 ℃ / 2-4 hours)

After manufacturing, the structural property values, electrical conductivity, and mechanical properties of these round rods with diameters of 13.40mm, 16.35mm, and 45.50mm are at the levels shown in Table 3.

Operation 3

热 Hot-rolled slabs composed of alloys 2 and 3 into rolled plates at a temperature of 650-730 ° C

冷 Cold-rolled these plates with a processing rate of 15 to 25%, combined with stress relief annealing as appropriate (300-450 ° C / 2-4 hours)

Add surface milling operations between processing steps as needed.

Operation 4

热 Hot-rolled slabs composed of alloys 2 and 3 into rolled plates at a temperature of 650-730 ° C

退火 Anneal these sheets (650 ° C / 3 hours) and cold-roll at a processing rate of 15 to 25%, and combine stress relief annealing (300-450 ° C / 2-4 hours) as appropriate

Add surface milling operations between processing steps as needed.

Step 5

热 Hot-rolled slab composed of alloys 2 and 3 at a temperature of 650-730 ° C For rolling

组合 The combination of cold rolling / annealing (630-720 ° C / 50 minutes-4 hours) for these plates with a processing degree of 15 to 65%

Add surface milling operations between processing steps as needed.

Specifically, in terms of the specifications of the alloys 2 and 3 prepared according to Step 5, the conductivity characteristic value can be further improved by performing additional stress relief annealing at a temperature of 250 to 450 ° C.

As far as the above embodiment is concerned, it should be pointed out that the β content in all 5 steps is 5-20%. More tests have shown that the beta content is preferably 5-30%. Among them, the island-like β phase embedded in the structure composed of the α matrix after the manufacturing is completed may be slightly different in appearance. When the β-phase content is further reduced, islands (to be precise) separated from each other will appear, and these islands may form some form of wedge-shaped filling structure at the boundary with the α-matrix microcrystals.

Claims (10)

An electrical connector containing a copper-zinc alloy, the copper-zinc alloy is composed of the following (unit: wt%): 28.0 to 36.0% Zn, 0.5 to 1.5% Si, 1.5 to 2.5% Mn, 0.2 to 1.0% Ni, 0.5 to 1.5% Al, 0.1 to 1.0% Fe, optionally further containing a maximum of 0.1% Pb, optionally further containing a maximum of 0.1% P, optionally further containing no more than 0.08% S, The residual amount of Cu and inevitable impurities are characterized in that a mixed silicide containing iron, nickel, and manganese is embedded in the matrix, and the structure is composed of an alpha matrix, which contains 10 to 25 vol% of a β phase and Over 20 vol% of the iron-nickel-manganese-containing mixed silicides, in this configuration, the iron-nickel-manganese-containing mixed silicides are columnar in form and spherical in the iron-nickel-rich mixed silicides. The electrical connector of claim 1, characterized by: 30.0 to 36.0% Zn, 0.6 to 1.1% Si, 1.5 to 2.2% Mn, 0.2 to 0.7% Ni, 0.5 to 1.0% Al, 0.3 to 0.5% Fe. The electrical connector of claim 2 is characterized by 33.5 to 36.0% Zn. The electrical connector of any one of claims 1 to 3, characterized in that the electrical conductivity of the alloy is at least 5.8 MS / m. The electrical connector of claim 4, characterized in that the electrical conductivity of the alloy is at least 10 MS / m. The electrical connector of claim 5, characterized in that the electrical conductivity of the alloy is at least 13 MS / m. The electrical connector made of copper-zinc alloy as claimed in claim 1, characterized in that the structure includes an alpha matrix, which contains 10 to 25 vol% β phase and not more than 20 vol% of mixed silicified iron-nickel-manganese The structure is constructed in a subsequent process, which includes at least one hot working and / or cold working and optionally further annealing steps. The electrical connection made of copper-zinc alloy as claimed in claim 7, characterized in that the alloy undergoes the following steps during its subsequent processing:-extrusion or hot rolling in a temperature range of 600 to 800 ° C,- At least one cold working. The electrical connection made of copper-zinc alloy as claimed in claim 7, characterized in that the alloy undergoes the following steps during its subsequent processing:-extrusion or hot rolling in a temperature range of 600 to 800 ° C,- At least one cold working is combined with at least one annealing performed in a temperature range of 250 to 700 ° C. For example, the electrical connection made of copper-zinc alloy according to claim 8 or 9, characterized in that in the subsequent processing, after the processing is completed, then at least one stress relief is performed in a temperature range of 250 to 450 ° C. annealing.