JP4181524B2 - Aluminum alloy clad plate for caulking, its manufacturing method and aluminum alloy terminal - Google Patents

Description

  The present invention relates to an aluminum alloy clad plate for caulking, a method for producing the same, and an aluminum alloy terminal produced using the same, and in particular, aluminum for caulking that can be used without stress relaxation even in a temperature range of about 170 ° C. The present invention relates to an alloy plate, a manufacturing method thereof, and an aluminum alloy terminal.

  Aluminum alloys are light in weight, high in strength, excellent in heat and electrical conductivity, and corrosion resistance, and thus are used in a wide range of fields such as daily goods such as beverage cans and pans, engines and peripheral parts, and electric wires.

  On the other hand, for example, when the aluminum alloy is used for screwing after being processed into a bolt shape, the fastening strength tends to decrease due to stress relaxation when used for a long time in a temperature environment of about 120 to 160 ° C. It was never used in the temperature range.

  Similarly, when the caulking process is performed, the caulking strength is likely to be reduced by stress relaxation in the temperature range of 120 to 160 ° C., and therefore, an aluminum alloy is not used for a component having a caulking portion.

  As described above, in the aluminum alloy, the stress relaxation phenomenon becomes remarkable due to creep or the like under a temperature condition of about 120 to 160 ° C. For this reason, it is rarely used alone, and is used in combination with other metals such as SUS (clad plate) in bolting or threading, etc., and is limited to applications that allow some deformation. Was the current situation.

On the other hand, copper alloys are used for electric wires and terminals because they are excellent in electrical conductivity, and are caulked in many parts, and stress relaxation is a general evaluation test (for example, Non-Patent Document 1).
Further, the stress relaxation property of the copper alloy at a temperature of 120 to 160 ° C. is that when C2600 (70% Cu—Zn alloy) is kept at a temperature of 160 ° C. for 1000 hours, the residual stress is 20% or less (stress relaxation 80%). (For example, see Non-Patent Document 2).
Edited by Yotaro Murakami, "Basics and Industrial Technology of Copper and Copper Alloys", 1st Edition, Japan Copper and Brass Association, May 25, 1988, p. 384 Edited by Yotaro Murakami, “Copper Products Data Book”, 1st Edition, Japan Copper and Brass Association, August 1, 1997, p. 187

  However, weight reduction cannot be achieved with a terminal or the like made of a copper alloy. If the weight of terminals and the like is pursued, it may be necessary to use an aluminum alloy even if the parts are not allowed to be deformed. When a terminal made of aluminum alloy is used for a long time in a temperature range of about 170 ° C., stress relaxation causes loosening of the crimped portion of the terminal, which cuts off current, or causes a problem that the electric wire is disconnected from the terminal. There was a fear. For this reason, there is a strong demand for the development of aluminum alloys with low creep or stress relaxation.

  The present invention has been made in view of such a problem, and can be bolted and caulked with a strong stress in the initial stage, and has a strength even when left in a temperature environment of about 170 ° C. for a long time. An aluminum alloy clad plate that is less deteriorated and has a low stress relaxation even when used in a temperature range of about 170 ° C. and excellent in electrical conductivity and corrosion resistance, a manufacturing method thereof, and an aluminum alloy terminal using the same The purpose is to provide.

The fact that the stress relaxation property of the aluminum alloy plate is inferior is a problem inherent to the aluminum alloy, and thus has not been a problem in the past.
However, the present inventors have conducted extensive experimental research to meet the recent demand for weight reduction of caulking products, and as a result, appropriately specify the composition and manufacturing method of the skin material and core material of the aluminum alloy clad plate. Thus, the present inventors have succeeded in finding an aluminum alloy with less stress relaxation and excellent corrosion resistance and suitable production conditions thereof, and completed the present invention.

  That is, the aluminum alloy clad plate for caulking of the present invention has a skin material made of aluminum having a purity of 99.0% by mass or more, Cu: 0.2 to 0.9% by mass, Mg: 0.6 to 1. 4% by mass, the balance is made of Al and inevitable impurities, and among the inevitable impurities, Si: 0.8% by mass or less, Fe: 0.6% by mass or less, Mn: 0.15% by mass or less , Cr: 0.3% by mass or less, Zn: 0.3% by mass or less, Ti: 0.1% by mass or less, and Zr: Core material made of an aluminum alloy limited to 0.15% by mass or less. The clad rate of the skin material is 2 to 10%, and the crystal grain size of the core material is 35 to 300 μm (Claim 1).

Thus, the aluminum alloy clad plate for caulking according to the present invention has high strength because the purity of the skin material and the composition of the alloy contained in the aluminum alloy of the core material are appropriately defined, and the crystal grain size of the core material is reduced. Since it is regulated within an appropriate range, it suppresses skin cracking and roughening during caulking, increases the area of the grain boundary, and stress is maintained even when left at a temperature of about 170 ° C for a long time. Relaxation is reduced.
In addition, since the aluminum alloy clad plate for caulking of the present invention is made of pure aluminum, the sacrificial anticorrosive effect acts on the surface of the skin material, compared with the case where the alloy clad plate is made of only an aluminum alloy. Thus, an aluminum alloy clad plate having excellent corrosion resistance can be obtained.
In addition, since the clad rate of the skin material is defined in an appropriate range, the aluminum alloy clad plate for caulking has good pressure-bonding properties between the skin material and the core material, and can impart high strength.

Also, this aluminum alloy clad plate for caulking has a stress relaxation rate of 60% or less after being applied for 30% under a temperature condition of 160 ° C., which is equivalent to caulking, with a working rate of 30%. It is preferable that it is present (claim 2).
As described above, since the stress relaxation rate under the above-described constant condition is defined to be an appropriate numerical value or more, it is possible to keep the stress relaxation small even when left at about 170 ° C. for a long time.

  The method for producing an aluminum alloy clad plate for caulking according to the present invention comprises a homogenized heat treatment of an aluminum ingot having a purity of 99.0% by mass or more, followed by hot rolling to produce a plate material for a skin material, and Cu : 0.2-0.9 mass%, Mg: 0.6-1.4 mass%, the balance consists of Al and inevitable impurities, Si: 0.8 mass% among the inevitable impurities Hereinafter, Fe: 0.6 mass% or less, Mn: 0.15 mass% or less, Cr: 0.3 mass% or less, Zn: 0.3 mass% or less, Ti: 0.1 mass% or less, Zr: 0 In the first step of producing a core ingot made of an aluminum alloy limited to 15% by mass or less, and homogenizing heat treatment of the core ingot, and in the hot rolling, produced in the first step The plate material for the skin material and the ingot for the core material are made of the skin material after the final cold rolling. In the second step of heating and hot rolling after laminating so that the lad rate is 2 to 10%, and in the cold rolling after the second step, the final cold rolling is performed at a processing rate of 7 to 60%. The method includes a third step and a fourth step in which heat treatment and cooling are performed after the third step (claim 3).

  Thus, in the manufacturing method of the aluminum alloy clad plate for caulking according to the present invention, the plate material for the skin material is produced from the aluminum ingot of the predetermined purity in the first step, and is made of the aluminum alloy of the predetermined composition. An ingot for the core material can be produced. And after bonding together the board | plate material for skin | leather materials and the ingot for core materials at a 2nd process, these can be crimped | bonded firmly by heating and performing hot rolling. In addition, the desired strength is achieved by appropriately changing the thickness of the ingot for the skin material and the core material to be laminated in the second step, and setting the cladding ratio of the skin material after the final cold rolling within a predetermined range. Can be obtained. Next, by performing the final cold rolling at a processing rate of 7 to 60% in the third step, the crystal grain size of the core material becomes an appropriate size, and an appropriate strength can be realized. Then, by performing heat treatment and cooling under appropriate conditions in the fourth step, the strength required for the fastening component can be maintained.

  In addition, it is preferable that the manufacturing method of this caulking aluminum alloy clad plate performs cold rolling and intermediate annealing between the hot rolling and the final cold rolling. More preferable strength can be obtained by performing cold rolling and intermediate annealing.

  The caulking aluminum alloy clad plate of the present invention can be used as an aluminum alloy terminal, that is, a terminal of an automotive part. Since this aluminum alloy terminal is composed of an aluminum alloy clad plate that satisfies the requirements specified in the present invention, it can reduce stress relaxation even when used in a temperature environment of about 170 ° C., and has conductivity and corrosion resistance. Can also implement a good terminal.

According to the present invention, it is possible to perform bolting and caulking with a strong stress in the initial stage. Further, even when left in a temperature environment of about 170 ° C. for a long time, there can be provided an aluminum alloy clad plate for caulking that has little reduction in strength, little stress relaxation, and excellent corrosion resistance.
Moreover, according to this invention, the manufacturing method suitable for manufacturing the said aluminum alloy clad board for crimping can be provided.
Furthermore, according to the present invention, it is possible to suitably provide a terminal made of an aluminum alloy that is lightweight, hardly corroded, has excellent conductivity, and has low stress relaxation. In particular, it can be suitably used as a terminal for automobile parts.

  Hereinafter, the aluminum alloy clad plate for caulking according to the present invention, the manufacturing method thereof, and the aluminum alloy terminal using the same will be described in detail.

[Aluminum alloy clad plate for caulking]
First, an aluminum alloy clad plate for caulking according to the present invention will be described.
For conductors such as terminals, high electrical conductivity (low surface contact resistance) is required, and among aluminum and aluminum alloys, pure aluminum (purity) specified as JIS H4000 as 1000 series It is clear that 99.0% by mass or more) is suitable. However, since pure aluminum has low strength, bolting and caulking with strong stress cannot be performed, and since stress relaxation is large, loosening occurs in the fastening part when left in a temperature environment of about 170 ° C. for a long time. Probability is high.

  On the other hand, as an aluminum alloy having high strength and low stress relaxation as a caulking alloy, it is preferable to use an aluminum alloy defined as 6000 series in JIS H 4000, but compared with pure aluminum, surface contact resistance and Corrosion resistance is poor.

  Therefore, the present inventors have a clad plate using an aluminum plate made of pure aluminum and an aluminum alloy plate made of a 6000 series aluminum alloy, and has characteristics necessary for conductor applications. A satisfactory caulking aluminum alloy clad plate could be obtained.

  That is, by using an aluminum plate made of aluminum having a purity of 99.0% by mass or more as a skin material, the requirements for conductivity (contact resistance) and corrosion resistance are satisfied, Cu: 0.2 to 0.9% by mass, Mg : 0.6 to 1.4% by mass, with the balance being Al and inevitable impurities, among the inevitable impurities, Si: 0.8% by mass or less, Fe: 0.6% by mass or less, Mn : Aluminum having a composition limited to 0.15% by mass or less, Cr: 0.3% by mass or less, Zn: 0.3% by mass or less, Ti: 0.1% by mass or less, Zr: 0.15% by mass or less The alloy plate was used as a core material, the clad rate was set to 2 to 10%, and the crystal grain size of the core material was set to 35 to 300 μm to satisfy the requirements for caulking workability, caulking strength, and stress relaxation properties.

[Skin]
First, the skin material of the aluminum alloy clad plate for caulking according to the present invention will be described.
(Aluminum with a purity of 99.0% by mass or more)
For the skin material, pure aluminum having a purity of 99.0% by mass or more is used in order to reduce the contact resistance of the surface to increase the conductivity and to improve the corrosion resistance. If the purity is less than 99.0% by mass, the electrical conductivity and contact resistance required for the caulking alloy cannot be satisfied. Moreover, if the purity is low, the sacrificial anticorrosive effect cannot be obtained effectively. Therefore, the purity of aluminum used for the skin material of the present invention is 99.0% by mass or more.

[Core]
Next, the reasons for limiting the contents of Cu and Mg, which are essential elements, of the composition of the core material of the aluminum alloy clad plate for caulking according to the present invention will be described.
(Cu: 0.2-0.9 mass%)
Cu is added to improve the strength of the plate and suppress stress relaxation due to precipitation of coarse β ′ phase (Mg—Si). If the Cu content is less than 0.2% by mass, sufficient effects cannot be obtained. Moreover, when Cu content exceeds 0.9 mass%, since these effects are saturated and a coarse precipitate is formed, caulking workability is reduced. Therefore, the Cu content is 0.2 to 0.9 mass%.

(Mg: 0.6-1.4% by mass)
For example, in the case where a fastening part such as a terminal is formed using the aluminum alloy clad plate for caulking of the present invention and another member is caulked using this terminal, The terminal needs to have some strength and elongation. In order to acquire these effects, it is necessary to contain 0.6 mass% or more of Mg. However, if the Mg content exceeds 1.4% by mass, the solid solubility limit is exceeded even in a temperature range of 170 ° C. or less, and Mg alone precipitates and causes vacancy movement, so stress is reduced. It becomes easy to relax. Therefore, Mg content shall be 0.6-1.4 mass%.

Hereinafter, the reason for limiting the contents of Si, Fe, Mn, Cr, Zn, Ti and Zr, which are elements included as inevitable impurities, in the composition of the aluminum alloy constituting the core material will be described. These unavoidable impurities are preferably not contained (that is, 0.0% by mass), but in the present invention, they can be used without any problem as long as the content is not more than the following.
(Si: 0.8% by mass or less)
Si, which is an inevitable impurity element, becomes a coarse β 'phase structure in an overaged state when held at 160 ° C. for a long time, and vacancies are generated to easily relieve stress. Accordingly, the Si content is 0.8% by mass or less. In addition, it is desirable that essentially no Si is contained. However, in normal production, about 0.4 to 0.6% by mass is often contained, and in that case, Cu is added to form a coarse β 'Prevents phase precipitation and migration of vacancies.

(Fe: 0.6 mass% or less)
If the Fe content exceeds 0.6% by mass, the crystal grains are likely to be refined, so that the crystal grain size is less than 35 μm. When the crystal grain size is less than 35 μm, the distance to the grain boundary, which is the vacancy disappearance site, is shortened and the area of the grain boundary is also increased, so that the stress relaxation property is deteriorated. Therefore, the Fe content is 0.6% by mass or less.

(Mn: 0.15 mass% or less)
When the Mn content exceeds 0.15% by mass, the stress relaxation property is lowered. Therefore, the Mn content is 0.15% by mass or less.

(Cr: 0.3% by mass or less)
If the Cr content exceeds 0.3% by mass, the crystal grains can be easily refined, so that the stress relaxation property is lowered. Therefore, the Cr content is 0.3% by mass or less.

(Zn: 0.3 mass% or less)
When the Zn content exceeds 0.3% by mass, the stress relaxation property is lowered. Therefore, the Zn content is set to 0.3% by mass or less.

(Ti: 0.1% by mass or less)
Ti contributes to refinement of the ingot structure, but when the content thereof exceeds 0.1% by mass, the stress relaxation property decreases. Therefore, the Ti content is 0.1% by mass or less.

(Zr: 0.15 mass% or less)
If the content of Zr exceeds 0.15% by mass, the giant compound Al ₃ Zr is likely to be produced, and the caulking processability is deteriorated. Therefore, the Zr content is 0.15% by mass or less.

(Clad rate: 2-10%)
When the clad rate of the skin material is less than 2%, the press-bonding property in the clad rolling is lowered and the production becomes difficult. In addition, when the cladding ratio exceeds 10%, the strength decreases. Therefore, the cladding rate of the skin material is 2 to 10%.

[Method for producing aluminum alloy clad plate for caulking]
Next, the manufacturing method of the aluminum alloy clad plate for caulking according to the present invention will be described in detail.
As a manufacturing method of the aluminum alloy clad plate for caulking according to the present invention, first, an ingot of aluminum having a purity of 99.0% by mass or more is subjected to homogenization heat treatment (550 to 630 ° C.) and then hot-rolled. A plate material for a skin material is produced (first step). In addition, the plate | board thickness of the board | plate material for skin | leather materials is suitably adjusted according to the thickness of the ingot of a core material so that the clad rate of the skin | leather material after final cold rolling may be 2-10%.
Moreover, Cu: 0.2-0.9 mass%, Mg: 0.6-1.4 mass% is contained, the remainder consists of Al and an unavoidable impurity, Si: 0.00% among the said unavoidable impurities. 8 mass% or less, Fe: 0.6 mass% or less, Mn: 0.15 mass% or less, Cr: 0.3 mass% or less, Zn: 0.3 mass% or less, Ti: 0.1 mass% or less, Zr: An ingot of an aluminum alloy limited to 0.15% by mass or less is subjected to homogenization heat treatment (450 to 550 ° C.) to produce an ingot for a core material (also in the first step).

Thereafter, the plate material for the skin material and the ingot for the core material are bonded together, heated, and then hot-rolled (second step).
Thereafter, the final cold rolling is performed at a processing rate of 7 to 60% (third step). At this time, if the processing rate of the final cold rolling is less than 7%, the recrystallized grains after the final heat treatment become too coarse, and if it exceeds 60%, the recrystallized grains become too fine.
Furthermore, as heat treatment, it is desirable to hold at a temperature of 500 to 570 ° C. for 1 hour or less and then cool at a rate of 1 ° C./second or more (fourth step). At this time, when the heating temperature is less than 500 ° C., the solid solution of the constituent elements is not sufficient, and it is difficult to obtain the intended strength during caulking and the stress relaxation resistance required during use, and the heating temperature exceeds 570 ° C. And there are concerns about burning. Further, if the heating time is longer than 1 hour, the crystal grain size becomes too coarse.

  In addition, in this manufacturing method, after performing homogenization heat processing, hot rolling, etc., cold rolling and intermediate annealing are performed, and then the final cold rolling is performed at a processing rate of 7 to 60%, followed by heat treatment. it can. As intermediate annealing conditions at that time, it is desirable to carry out at a temperature of 340 to 400 ° C. for 30 minutes or more.

  When an aluminum alloy clad plate is produced by a manufacturing method under such conditions using a skin material and a core material having the above-described composition, an aluminum alloy clad plate for caulking with the performance desired in the present invention can be realized. it can.

(Crystal grain size of core material: 35 to 300 μm)
When the crystal grain size of the core material is less than 35 μm, the distance to the grain boundary, which is the vacancy disappearance site, is shortened and the area of the grain boundary is also increased, so that the stress relaxation property is deteriorated. On the other hand, when the crystal grain size of the core material exceeds 300 μm, it causes skin cracking and roughening during caulking. Therefore, in the present invention, the crystal grain size of the core material is set to 35 to 300 μm.

The aluminum alloy clad plate for caulking processed by the method for producing an aluminum alloy clad plate for caulking according to the present invention gives a machining with a machining rate of 30%, corresponding to caulking, and has a temperature condition of 160 ° C. It is preferable that the stress relaxation rate after being held for 100 hours below is 60% or less.
If the stress relaxation rate exceeds 60% after applying a machining rate of 30%, which corresponds to caulking, and maintaining the temperature at 160 ° C. for 100 hours, loosening occurs in the fastening part in actual use. Power is cut off. Or it becomes easy to generate | occur | produce the problem that an electric wire will come off from a terminal. Therefore, the stress relaxation rate under the same conditions is set to 60% or less.

[Aluminum alloy terminals]
Next, an aluminum alloy terminal according to the present invention will be described with reference to FIGS. In addition, Fig.1 (a) is a top view which shows the storage battery electric wire board terminal for motor vehicles, FIG.1 (b) is the side view. FIG. 2 (a) is a plan view showing a round plate terminal for automobiles, and FIG. 2 (b) is a side view thereof. Further, FIG. 3A is a perspective view showing an example of a state in which the aluminum alloy terminal of the present invention is attached to the wiring, and FIG. 3B is an enlarged view showing the connecting portion.

  The aluminum alloy terminal of the present invention shown in FIGS. 1 to 3 is, for example, between a motor and an inverter, between a battery and an inverter, and between a battery and a relay box in an electric vehicle, a hybrid vehicle, and a conventional gasoline vehicle. It can be suitably used as a terminal of an automobile part to be attached to a wiring or the like that connects between them (not shown).

These terminals can be manufactured by a conventional method. For example, an aluminum alloy clad plate for caulking manufactured by the method for producing an aluminum alloy clad plate for caulking according to the present invention is used in a mold apparatus having a mold of a predetermined shape, thereby allowing a terminal of any shape Can be obtained.
Thus, since the terminal using the aluminum alloy clad plate for caulking according to the present invention has a predetermined composition, it is excellent in corrosion resistance and conductivity, and is composed of aluminum and an aluminum alloy. It is lighter than a copper alloy terminal and can be widely used as a terminal for automobile parts.

Next, the effect of the invention example that satisfies the requirements of the present invention will be specifically described in comparison with the effect of the comparative example that does not satisfy any of the requirements of the present invention. That is, for the inventive example and the comparative example, tests and evaluations described in the following first to third examples were performed. It should be noted that the numbers underlined in Tables 1 to 6 shown in the first to third examples do not satisfy the requirements prescribed in the present invention or the predetermined evaluation results. Show.
<First embodiment>
In the first embodiment, an aluminum alloy clad plate for caulking according to the present invention will be described.
As a chemical component of the skin material, as shown in Table 1, aluminum having a purity of 98.5 to 99.5% by mass was used. As the core material, as shown in Table 1, an aluminum alloy having chemical components represented by alloy numbers 1 to 25 was used. In addition, what was underlined in Table 1 has shown that the chemical composition has remove | deviated from the range prescribed | regulated by this invention.

And the aluminum alloy clad board shown to the alloy numbers 1-25 was produced by clad rolling using the ingot of the aluminum board | plate material for skin materials, and the aluminum alloy for core materials.
As a manufacturing method of the aluminum alloy clad plate shown in Alloy Nos. 1 to 25, first, an aluminum ingot having the purity shown in Table 1 is subjected to homogenization heat treatment at 600 ° C. and then hot-rolled to obtain a plate material for skin material Is made. Ingots of aluminum alloys having the compositions shown in Table 1 were homogenized and heat treated at 510 ° C. to form ingots for core materials, which were then laminated together, reheated, hot rolled, and then cold rolled. And intermediate annealing (370 ° C. × 4 hours). Thereafter, the final cold rolling was performed at a processing rate of 50% to obtain an aluminum alloy plate having a plate thickness of 1.5 mm. The cladding ratio of the skin material at this time was 5%.
Next, it was kept for 30 seconds under a temperature condition of 530 ° C. and then cooled at a rate of 5 ° C./second. In this way, aluminum alloy clad plates indicated by alloy numbers 1 to 25 were produced.

  As shown in Table 1, the aluminum alloy clad plates with alloy numbers 1 to 13 are invention examples that satisfy the requirements of the present invention, and have compositions within the range defined by the present invention.

On the other hand, the aluminum alloy clad plates having alloy numbers 14 to 25 are comparative examples that do not satisfy the requirements of the present invention.
That is, the aluminum alloy clad plate of alloy number 14 has a purity of 98.5% for the skin material, which is less than the lower limit. Further, the aluminum alloy clad plates of alloy numbers 15 and 16 are those in which the content of Cu in the core material is less than the lower limit value or exceeds the upper limit value of the range defined in the present invention. In the alloy clad plate, the Mg content in the core material is less than the lower limit value or exceeds the upper limit value in the range defined in the present invention. Further, in the aluminum alloy clad plates of alloy numbers 19 to 25, Si, Fe, Mn, Cr, Zn, Ti and Zr, which are inevitable impurities in the core material, each exceed the upper limit of the range defined in the present invention. Is.
The following tests and evaluations were performed using the invention examples and comparative examples shown in these alloy numbers 1 to 25.

(Tensile properties)
About the aluminum alloy clad board of alloy numbers 1-25, the No. 5 test piece described in JISZ2201 was produced so that a tension direction might become parallel to a rolling direction. Then, about the No. 5 test piece of each aluminum alloy plate, the tensile test by the metallic-material tension test method described in JISZ2241 was implemented, and tensile strength, yield strength, and elongation were calculated | required.

[Caulking workability]
The caulking workability was evaluated by a 90 ° bending test (R = 0.5). A sample in which rough skin and skin crack did not occur was evaluated as having good caulking workability, and “◯” was evaluated. A sample having rough skin and crack in the skin was evaluated as poor, and “×” was determined.

[Caulking strength]
The caulking strength was evaluated by the rigidity after caulking. The caulking strength is proportional to the plate thickness and proof stress. Therefore, assuming the caulking process, the proof stress after the cold rolling process with a processing rate of 30% (the proof stress after the cold rolling process assuming the caulking process) is obtained. When the product was calculated to be 260 mm · N / mm ² or more, the caulking strength was evaluated to be acceptable.

[Stress relaxation]
The evaluation of stress relaxation was performed by a stress relaxation test shown in the schematic diagram of FIG.
First, using each aluminum alloy clad plate of alloy numbers 1 to 25, cold rolling with a rolling rate of 30% was performed assuming caulking, and then a test piece having a width of 10 mm and a length of 150 mm was cut out. Next, as shown in FIG. 4, the test piece S1 is deformed by applying a stress of 80% of the proof stress by the cantilever type described in the Japan Electronic Materials Industry Association Standard EMAS-3003. The amount of deformation (δ ₀ ) is measured. Then, after maintaining the state at 160 ° C. for 100 hours, the stress is removed and the deformation amount (ε) of the test piece is measured again. The stress relaxation rate serving as an evaluation index of stress relaxation properties can be obtained by “stress relaxation rate = (ε / δ ₀ ) × 100”. Those having a stress relaxation rate of 60% or less were regarded as being acceptable as having excellent stress relaxation properties (small stress relaxation).

[Contact resistance]
FIG. 5A is a perspective view showing a method for measuring contact resistance, FIG. 5B is a perspective view showing the contact shown in FIG. 5A, and FIG. 5C shows its shape. It is a side view.
The contact resistance is obtained by cooling the aluminum alloy plate S2 of alloy numbers 1 to 25 heated at 160 ° C. for 100 hours in the air at room temperature, and then subjecting it to the electrical contact simulator 30 shown in FIG. Measurement was performed by a four-terminal method using currents I and I and voltages V and V. As shown in FIGS. 5B and 5C, the measurement was performed using a contact 31 obtained by bending a gold wire having a diameter of 1 mm and setting the load ΔW to 5N. An aluminum alloy plate having a contact resistance value of 0.32 mΩ or less was accepted.
Table 2 shows the results of the above tests and evaluations.

  As shown in Table 2, the aluminum alloy clad plates shown in Alloy Nos. 1 to 13, which are invention examples, are excellent in caulking workability because the chemical components of the skin material and the core material are all within the range defined in the present invention. , Crimping strength, stress relaxation property (stress relaxation rate) and contact resistance.

On the other hand, in the aluminum alloy clad plates shown as alloy numbers 14 to 25 which are comparative examples, since any one of the chemical components defined in the present invention is not satisfied, the evaluation was as follows.
That is, the aluminum alloy clad plate shown in Alloy No. 14 has a high contact resistance because the purity of the aluminum of the skin material is less than the lower limit of the range defined in the present invention.

The aluminum alloy clad plate shown in Alloy No. 15 was inferior in stress relaxation because the Cu content in the core material was less than the lower limit of the range defined in the present invention.
Moreover, the aluminum alloy clad plate shown in alloy number 16 was inferior in caulking workability because the Cu content in the core material exceeded the upper limit of the range defined in the present invention.

The aluminum alloy clad plate shown in Alloy No. 17 was inferior in caulking strength because the Mg content in the core material was less than the lower limit of the range defined in the present invention.
Moreover, since the content of Mg in the core material exceeds the upper limit of the range specified in the present invention, the aluminum alloy clad plate shown as Alloy No. 18 has poor stress relaxation properties. Moreover, the contact resistance was also high.

Furthermore, the aluminum alloy clad plate shown in Alloy No. 19 was inferior in stress relaxation because the Si content in the core material exceeded the upper limit of the range defined in the present invention. Moreover, the contact resistance was also high.
In addition, the aluminum alloy clad plate indicated by alloy number 20 was inferior in stress relaxation because the Fe content in the core material exceeded the upper limit of the range defined in the present invention.

And the aluminum alloy clad plates shown in alloy numbers 21 to 24 are inferior in stress relaxation because the contents of Mn, Cr, Zn or Ti in the core material exceed the upper limits of the ranges defined in the present invention. It was a thing.
Further, the aluminum alloy clad plate indicated by alloy number 25 was inferior in caulking workability because the Zr content in the core material exceeded the upper limit of the range defined in the present invention.

<Second embodiment>
In the second embodiment, the aluminum alloy clad plate for caulking according to the present invention will be further described.
First, aluminum having a purity of 99.5% by mass is used as the skin material, and an aluminum alloy having chemical components shown in Table 3 is used as the core material. The cladding ratio between the skin material and the core material is 1 to 15%. The aluminum alloy clad plate of alloy numbers 26 to 29 was changed to 4 levels between.

Aluminum alloy clad plates shown in Alloy Nos. 26 to 29 were produced by clad rolling using an aluminum plate material for the skin material and an aluminum alloy ingot for the core material.
As a manufacturing method of the aluminum alloy clad plate shown in Alloy Nos. 26 to 29, first, an aluminum ingot having the purity shown in Table 3 is homogenized by heat treatment at 600 ° C. and then hot-rolled to obtain a plate material for skin material. Is made. Ingots of aluminum alloy having the composition shown in Table 3 were homogenized and heat treated at 510 ° C. to form ingots for core materials, which were laminated together, reheated, hot rolled, and then cold rolled. And intermediate annealing (370 ° C. × 4 hours). Thereafter, the final cold rolling was performed at a processing rate of 50% to obtain an aluminum alloy plate having a plate thickness of 1.5 mm.
Furthermore, after hold | maintaining for 30 second on 530 degreeC temperature conditions, it cooled at the speed | rate of 5 degree-C / sec, and produced the aluminum alloy plate of alloy numbers 26-29. And about these aluminum alloy plates, the said various tests and evaluation were performed. The results are shown in Table 4.

  As shown in Table 4, the aluminum alloy clad plate shown in Alloy Nos. 26 and 27 satisfying the requirements of the present invention, the chemical composition of the skin material and the core material, the clad rate is all within the range specified in the present invention, Excellent caulking workability, caulking strength and stress relaxation properties are shown.

On the other hand, since the clad rate of the aluminum alloy clad plate shown by Alloy No. 28 is less than the lower limit of the range defined in the present invention, the crimpability in the clad rolling is inferior, and the final product cannot be manufactured.
Moreover, since the clad rate exceeded the upper limit of the range prescribed | regulated by this invention, the aluminum alloy clad board shown to the alloy number 29 was inferior to stress relaxation property. Also, the caulking strength was inferior.

<Third embodiment>
Next, in the third embodiment, a method for producing an aluminum alloy clad plate for caulking according to the present invention will be described.
As the chemical component of the skin material, aluminum having a purity of 99.5% by mass was used. Moreover, the aluminum alloy shown in the alloy number 1 of the said Table 1 was used as a chemical component of a core material. Using the aluminum plate material for the skin material and the aluminum alloy ingot for the core material, the processing rate in the final cold rolling after the intermediate annealing is changed to 4 levels between 5 to 65%, and the alloy Aluminum alloy plates with numbers 30 to 33 were produced.

As a manufacturing method thereof, first, an aluminum ingot having the above purity is subjected to a homogenization heat treatment at 600 ° C., and then hot-rolled to produce a plate material for a skin material. In addition, as described above, an ingot of aluminum alloy having the composition shown in Table 1 was homogenized by heat treatment at 510 ° C. to obtain an ingot for core material, and these were laminated and reheated and hot rolled. Thereafter, cold rolling and intermediate annealing (370 ° C. × 4 hours) were performed. Thereafter, final cold rolling was performed at a processing rate of four levels to obtain an aluminum alloy plate having a plate thickness of 1.5 mm. The cladding ratio of the skin material at this time was 5%.
Next, after a solution treatment was performed by maintaining the temperature at 530 ° C. for 30 seconds, the solution was cooled at a rate of 5 ° C./second. In this way, aluminum alloy clad plates shown in alloy numbers 30 to 33 were produced.

  These aluminum alloy plates 30 to 33 were tested and evaluated in the same manner as in the first and second examples. The crystal grain size of the core material in Table 6 was measured by etching the rolled surface of the aluminum alloy plate by the Barker method and using a cutting method by observation with an optical microscope.

  Table 5 below shows these production conditions, and Table 6 below shows the evaluation results. Tables 5 and 6 also show the production conditions and evaluation results of the aluminum alloy plate of Alloy No. 1 produced in the first example as a standard sample.

As shown in Table 6, the aluminum alloy clad plates shown in Alloy Nos. 30 and 31, which are invention examples that satisfy the requirements of the present invention, exhibited excellent caulking workability, caulking strength, and stress relaxation properties.
On the other hand, since the cold rolling processing rate is lower than the range specified in the present invention, and the aluminum alloy clad plate shown in Alloy No. 32 as a comparative example of the present invention has a coarse crystal grain size (greater than 300 μm), Caulking workability was inferior.
Further, the aluminum alloy clad plate shown in Alloy No. 33 having a cold rolling ratio higher than the range specified in the present invention was inferior in stress relaxation because the crystal grain size was fine (less than 35 μm).

(A) is a top view which shows the storage battery electric wire board terminal for motor vehicles, (b) is the side view. (A) is a top view which shows the round board terminal for motor vehicles, (b) is the side view. (A) is a perspective view which shows an example of the state by which the aluminum alloy terminal of this invention was attached to wiring, (b) is an enlarged view which shows the connection part. It is a schematic diagram of the stress relaxation test in the aluminum alloy clad board of this invention. (A) is a perspective view which shows the measuring method of contact resistance, (b) is a perspective view which shows the contactor shown to (a), (c) is a side view which shows the shape.

Explanation of symbols

11 Automotive battery terminal plate 21, 21a Round plate terminal for automobile

Claims (5)

A skin material made of aluminum having a purity of 99.0% by mass or more;
Cu: 0.2 to 0.9% by mass, Mg: 0.6 to 1.4% by mass, the balance is made of Al and inevitable impurities, and among the inevitable impurities, Si: 0.8% by mass %: Fe: 0.6 mass% or less, Mn: 0.15 mass% or less, Cr: 0.3 mass% or less, Zn: 0.3 mass% or less, Ti: 0.1 mass% or less, Zr: An aluminum alloy clad plate for caulking, comprising a core material made of an aluminum alloy limited to 0.15% by mass or less,
A clad rate of the skin material is 2 to 10%, and a crystal grain size of the core material is 35 to 300 μm. An aluminum alloy clad plate for caulking.   2. The stress relaxation rate after giving a processing with a processing rate of 30% corresponding to caulking and holding it at a temperature of 160 ° C. for 100 hours is 60% or less. Aluminum alloy clad plate for caulking. An aluminum ingot having a purity of 99.0% by mass or more is subjected to homogenization heat treatment and hot-rolled to produce a plate material for a skin material,
Cu: 0.2 to 0.9% by mass, Mg: 0.6 to 1.4% by mass, the balance is made of Al and inevitable impurities, and among the inevitable impurities, Si: 0.8% by mass %: Fe: 0.6 mass% or less, Mn: 0.15 mass% or less, Cr: 0.3 mass% or less, Zn: 0.3 mass% or less, Ti: 0.1 mass% or less, Zr: A first step of producing an ingot for a core material made of an aluminum alloy limited to 0.15% by mass or less, and homogenizing heat treatment of the ingot for the core material;
In the hot rolling, the plate material for the skin material and the ingot for the core material produced in the first step were bonded so that the cladding ratio of the skin material after the final cold rolling was 2 to 10%. Then, a second step of heating and hot rolling,
In the cold rolling after the second step, a third step of final cold rolling at a processing rate of 7 to 60%;
A fourth step of performing heat treatment and cooling after the third step;
A method for producing an aluminum alloy clad plate for caulking.   The method for producing an aluminum alloy clad plate for caulking according to claim 3, wherein cold rolling and intermediate annealing are performed between the hot rolling and the final cold rolling.   An aluminum alloy terminal manufactured using the aluminum alloy clad plate for caulking according to claim 1.

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