KR102160505B1 - Fabrication method of lightweight thermally conductive clad sheet, and the clad sheet thereby - Google Patents

Abstract

The present invention relates to a manufacturing method of a hybrid wide plate and the wide plate manufactured by the method. More specifically, the present invention relates to the method for manufacturing the hybrid wide plate, comprising the following steps of: laminating a first copper plate, an aluminum plate, and a second copper plate (S1); rolling a plate material laminated in the step S1 (S2); and plating the rolled plate (S3). A weight of the wide plate manufactured through the above method is 2.5t, and a width thereof is equal to or less than 600 mm. In addition, the wide plate is lightweight and has excellent conductivity.

Description

Fabrication method of lightweight thermally conductive clad sheet, and the clad sheet thereby}

The present invention relates to a method of manufacturing a lightweight conductive hybrid clad plate and a clad plate manufactured accordingly.

In general, a clad plate is a multilayer composite plate obtained by overlapping and joining two or more metal plate materials having different properties, and is a plate having the characteristics of each material evenly. A method of joining a metal plate is generally used in which the plate is laminated at room temperature or high temperature and then rolled or cast.

On the other hand, aluminum alloy is a material that maintains the light properties of aluminum by adding a certain amount of alloying elements to aluminum and has various characteristics such as high strength, corrosion resistance, and workability. Depending on the type and amount of alloying elements added, aluminum alloys are 1XXX series with 1% or less of alloy elements added, 2XXX series with copper, 3XXX series with manganese, 4XXX series with silicon, and 4XXX series with magnesium added. It is divided into 5XXX series, 6XXX series with magnesium and silicon added, and 7XXX series with zinc. A clad plate composed of two or more aluminum alloy plates having different properties may have various complex characteristics depending on the type of the constituent plate. For example, a multilayer clad plate having high strength, high corrosion resistance, and workability can be manufactured by bonding 6XXX-based plates having excellent corrosion resistance to both surfaces of 5XXX-based plates having excellent strength and workability.

Currently, the most commonly used method for manufacturing clad plates is the rolling bonding method, after degreasing the surface of the plate, forming irregularities after going through processes such as pickling, brushing, papering, and blasting, and rolling it at a certain reduction ratio to make a clad plate. can do. At this time, the rolling reduction ratio for joining the aluminum alloy plate by the rolling bonding method is disclosed as 40 to 80% according to the prior art described in Korean Patent Registration No. 10-0707479. However, in the prior art, in order to manufacture a clad plate, an artificial uneven formation step through a chemical or mechanical method must be included on the surface of the plate, and accordingly, there is a problem of generating by-products such as a complicated manufacturing process and metal powder, and to solve this problem Ancillary equipment is required. In addition, since the 5XXX and 6XXX-based aluminum alloy plates have high strength, a high reduction ratio must be applied to perform rolling joining, and thus a large rolling mill with a large capacity is required. Furthermore, there is a problem that cracks easily occur during the rolling bonding process of the 5XXX, 6XXX-based aluminum alloy plates.

When manufacturing a clad plate, it is possible to reduce the reduction rate for joining and suppress the occurrence of cracks by charging the plate to a heating furnace and heating it before rolling. At this time, as a means for heating the plate, a heating method using a hot wire is typical. In the heating method by a hot wire, a plate is charged into a heating furnace where the inside is maintained at a constant temperature, and heating is performed by convection of gas inside the heating furnace. However, such convection heating takes a long time to heat the plate material to a desired temperature, and since the heating furnace must be sealed, there is a problem that it is difficult to apply to a continuous manufacturing process, which is a method of heating the plate material while passing it through the heating furnace. In addition, in the case of high-strength aluminum alloys such as 5XXX and 6XXX series, embrittlement may occur when heated for a long time, so the hot wire heating method with a long heating time is not suitable as a plate heating method for manufacturing clad plates.

As a result of intensive research to develop a method for manufacturing a lightweight conductive hybrid wide-width plate, the present inventors completed the present invention by confirming the optimization conditions of each process to manufacture a clad plate.

Accordingly, an object of the present invention is to provide a method of manufacturing a hybrid wide plate material.

However, the technical problem to be achieved by the present invention is not limited to the above-mentioned problems, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the object of the present invention as described above, the present invention is a first copper plate; Aluminum plate; And laminating a second copper plate (S1). And

It provides a method of manufacturing a hybrid wide-width plate comprising the step (S2) of rolling the laminated plate in the step S1.

As an embodiment of the present invention, the method is characterized in that it further comprises a step (S3) of plating the rolled plate.

In another embodiment of the present invention, the first copper plate, aluminum plate, and second copper plate are surface-treated by a brushing process.

As another embodiment of the present invention, the first copper plate; Aluminum plate; And an intermetallic compound layer is formed between the second copper plate, and the thickness of the compound layer is 0.5 μm or less or 10 μm or more.

As another embodiment of the present invention, the rolling of step S2 is performed at a minimum reduction rate of 50% or more, and is performed at 200 to 450° C. or less.

In another embodiment of the present invention, a rolling oil having a viscosity of 50 (40°C ㎟, ㎟/s) or less is used as a rolling oil for rolling in step S2.

As another embodiment of the present invention, the plating in step S3 is characterized in that the plating is plated to a thickness of 0.1㎛ to 20㎛.

In another embodiment of the present invention, the plating step may include a nickel plating step; And a tin plating step.

In another embodiment of the present invention, the plating step may include a nickel plating step; And a tin plating step.

In another embodiment of the present invention, the nickel plating is performed at 52° C. for 1 to 30 minutes at a voltage of 2.5 V and a current of 200 A,

The tin plating is characterized in that it is performed at a voltage of 2.2V and a current of 160A at 15 to 35°C for 1 to 30 minutes.

In addition, the present invention provides a hybrid wide plate material manufactured by the above method.

As an embodiment of the present invention, the plate is characterized in that the grade is less than 2.5t, width 600mm.

The method of manufacturing a hybrid wide plate according to the present invention is manufactured by optimizing the conditions of each process, and has an advantage of being lightweight and excellent in conductivity. The plate material can be usefully used as a component requiring light weight and conductivity such as a bus bar.

1 shows the result of confirming the change in bonding force according to the reduction ratio in Example 1.
Figure 2 shows the results of improving the cross-section of the Al material during slitting in Example 2.
FIG. 3 shows a photograph of the generation of intermetallic compounds at the interface after heat treatment of a Cu/Al/Cu material using SEM.
4 shows a schematic diagram of a cladding manufacturing process.
5 shows the clad metal material used in this example.
6 shows a plating process of a Cu/Al/Cu clad metal.
7 shows the result of the change in the thickness of the plating layer of the clad metal over time.
8 shows a deep drawing test process.
9 shows the results confirmed through the deep drawing test process.
10 shows the results of the bending repetition test.
11 shows a drawing forming process for measuring a spring bag.
12 shows a photograph of a specimen after drawing molding for springback measurement.
13 shows a method of measuring springback.
14 shows a photograph of the universal material testing equipment and V-bending mold used in Examples.
15 shows the results of the V bending test.
16 shows the molding limit diagram (FLD) test process and principle.
17A shows a clad metal material before the dome mounting test.
17B shows the clad metal material after the dome mounting test.
18 is a graph showing the results of the dome mounting test using a strain measuring device (Grid Pattern Analyzer).
19 shows a process of forming analysis of a Cu/Al/Cu clad metal busbar.
20A to 20C show the forming process of the bus bar.
21 shows the results of analyzing the crack generation area when the clad metal is molded into a bus bar shape.
22 shows the results of analyzing the wrinkle generation area.
23 shows the results of analyzing the spring back phenomenon after product molding.
24 shows a jig for measuring electrical conductivity.
25 shows the characteristics of a Cu/Al/Cu clad metal material.
26 shows the result of calculating the conductivity by measuring the resistance of a good/defective clad metal material.
27 shows the results of measuring the conductivity before and after the thermal shock and salt spray test.

As a result of intensive research to develop a method for manufacturing a hybrid wide plate, the present inventors have been optimizing the conditions and methods of each manufacturing process, and when manufacturing a hybrid wide plate according to the above conditions, light weight, conductivity and moldability are excellent. It was confirmed that the present invention was completed.

Accordingly, the present invention provides a method of manufacturing a hybrid wide plate material comprising the following steps:

First copper plate; Aluminum plate; And laminating a second copper plate (S1). And

Rolling the laminated plate in the step S1 (S2).

In addition, the manufacturing method may optionally further include a step (S3) of plating the rolled plate.

The first copper plate, the aluminum plate, and the second copper plate are surface-treated by a brushing process, the method of manufacturing a hybrid wide plate.

In the present invention, the first copper plate; Aluminum plate; And an intermetallic compound layer is formed between the second copper plate, and the thickness of the compound layer is 0.001 μm to 3.0 μm. More preferably, it is 0.01㎛ to 0.5㎛ so that both conductivity and moldability can be obtained.

The rolling of step S2 is performed at a minimum reduction rate of 50% or more, and is performed at 200 to 450° C., more preferably, it is preferably performed at a minimum reduction ratio of 60% or more.

In the step S2, a rolling oil having a viscosity of 50 (40°C ㎟, ㎟/s) or less may be used as a rolling oil for rolling, but is not limited to the rolling oil.

In the step S3, the plating may be plated to a thickness of 0.1 μm to 20 μm. There is no limitation on the method of plating, but the plating step may include a nickel plating step; And a tin plating step.

The nickel plating is performed at a voltage of 2.5V and a current of 200A at 52°C for 1 to 30 minutes, and then tin plating is performed at a voltage of 2.2V and a current of 160A at 15 to 35°C for 1 to 30 minutes, considering conductivity. When it is most desirable.

In addition, the present invention provides a hybrid wide plate manufactured by the above method.

The plate is characterized in that the grade is less than 2.5t, width 600mm.

Hereinafter, a preferred embodiment is presented to aid the understanding of the present invention. However, the following examples are provided for easier understanding of the present invention, and the contents of the present invention are not limited by the examples.

[Example]

Example 1. Preliminary experiment for manufacturing clad plate

In Example 1, a brushing process was adopted as the clad surface treatment method to secure bonding strength, and reduction was performed based on a minimum reduction amount of 50% or more, and the heat treatment was performed at 400°C or less. As a result, damage to the edge of the Al raw material in the slitting process or the unclean shear surface appeared as an edge effect phenomenon due to the pressing force during the clad process, causing the plate to break, and the crack width and occurrence frequency increased. When the rolling oil is changed to add lubricity to suppress surface cracking, the rolling force must act as a driving force that generates the bonding force at the interface, but the rolling force is lowered due to the lubricity.

Therefore, in the later process, the stabilization of work by worker skill cultivation and equipment modification in the slitting process was promoted to reduce edge cracks. In addition, by using the shape of the rolling roll or the bending system according to the increase of the plate width, the occurrence of cracks is reduced by stably coming out of the plate shape, and the plate material is bitten by the rolling roll without slip by adjusting the rolling oil and changing the surface roughness of the rolling roll. It was induced to come out naturally.

Example 2. Checking the optimization conditions of the plate manufacturing process

2.1. Surface treatment

Considering the contents of the prior art (Sci.Technol.Adv.Mater.9(2008)023001), a difference in bonding strength occurs according to the state of the interface and the amount of reduction, and the surface treatment conditions treated with alkali are the most It was confirmed that a high bonding strength was shown. If the process of sufficient environmental treatment facilities is considered, it would be better to use the related surface treatment, but when considering the generation and treatment of mass production and environmental pollution, it was considered that it would be better to exclude chemical treatment of the surface as much as possible. Therefore, a brushing process was adopted.

2.2. Rolling process

As shown in Figure 1, it was confirmed that the change in the bonding force according to the reduction ratio. However, in case of overpressure, the amount of edge crack generation of the plate material is very large, and the same tendency was observed even when the thickness of the initial input material is thick.Thus, in the case of thick input materials, in the case of the existing single pressure reduction method, It was judged that change was necessary.

In order to minimize the overall thickness deviation, the number of rolling passes must be increased by increasing the input thickness, but it may be a problem in the increase of the thickness and occurrence of cracks according to the amount of reduction, and the increase in work loss. Accordingly, the cross-section of the Al material during slitting was improved as shown in FIG. 2 to minimize the occurrence of cracks during the rolling operation.

2.3. Heat treatment

As the heat treatment temperature increases and the holding time increases, the thickness of the intermetallic compound layer increases. 3 is a photograph taken using SEM of the generation of intermetallic compounds at the interface after heat treatment of a Cu/Al/Cu material. The final heat treatment conditions were controlled within a temperature and time of 400°C or less.

As shown in FIG. 3, it was confirmed that the amount of intermetallic compound produced was greatly increased as the heat treatment temperature increased. It was confirmed that the generation of intermetallic compounds increased according to the heat treatment time and conditions.

Through the above results, in the present invention, the cladding manufacturing process was established by using the surface treatment method as the brushing process, the reduction amount being 60% or more, and the heat treatment being 400°C or less. A schematic diagram of the established manufacturing process is shown in FIG. 4.

Example 3. Confirmation of improvement of adhesion through surface treatment

Plating characteristics

There are various types of plating, such as Cr, Ni, Sn, Zn, and Ag, but considering workability (cost, ease of plating, interfacial stability in the clad process, etc.), Ni plating was judged to be the most efficient. Cr plating is only possible with hard plating, so there is a problem of cracking the surface plating layer during rolling, and Sn, Zn plating has a low melting point, so it is highly likely to cause problems in rolling and heat treatment processes.

Example 4. Material properties check

4.1 Checking plating properties

In Example 4, in order to check the plating characteristics of the clad metal material laminated with 3 layers of Cu/Al/Cu, the plating time was set as a variable to check the change in the thickness of the plating layer. 5 is a clad metal material used in this example, and Sn plating was performed after Ni strike treatment. The reason for the Ni strike treatment in Sn plating is that in the clad metal stacked in three layers, Al is found to have a remarkably low Sn plating adhesion, so the problem that peeling is easy was found. As a method to solve this problem, Ni strike treatment before Sn plating is performed. When doing so, it was confirmed that the adhesion of the Sn plating layer was improved.

The plating conditions performed in this example are shown in Table 1. For Ni strike, the voltage/current condition was set at 2.5V/200A, and the plating temperature was set at about 50°C, and the plating time was set as a variable and changed for 0~30min. For Sn plating, the voltage/current condition was 2.2V/160A, and the plating time was changed for 1~30min at room temperature. The existing mass-produced plating time is Ni: 5min, Sn: 5.5min, and the plating time was reduced in units of 1min to observe the change in the thickness of the plating layer, and increase the plating time drastically to check the change in the thickness of the plating layer above the standard plating time. Plating proceeded.

Ni Sn Voltage (V)/current (A) 2.5/200 2.2/160 Plating temperature (℃) 52 Room temperature Plating time (min) 0~30 1~30

6 shows the plating process of the Cu/Al/Cu clad metal. The plating process is largely carried out by pickling, washing, activation, plating, and drying. All processes were carried out continuously.

7 is a result of the change in the thickness of the plating layer of the clad metal over time. The plating thickness was measured by measuring 2 points at the center and 2 points at the edge of the specimen, indicating an average value. In the case of Ni strike, as the plating time elapsed, the thickness of the plating layer tended to increase, and the plating layer was formed from a minimum of 0.3 μm to a maximum of 4.0 μm. In the case of Sn plating, as with Ni, the plating layer thickness increased as the plating time elapsed, and the plating layer was formed from a minimum of 0.8 µm to a maximum of 21.2 µm, and it was found that the amount of change in the plating thickness according to the plating time was larger than that of Ni. As a result of comparing the plating thickness according to the location of the specimen, it was confirmed that the plating layer at the edge was formed thicker than the center, regardless of the plating type, and the Sn plating layer was relatively thicker than the Ni plating thickness. Plating time of about 4 to 5 min or more is required to form a Ni strike layer of 1 μm or more, and a plating time of about 3 to 10 min is required to form a Sn plating layer of 2 to 8 μm.

4.2. Formability condition check

Tensile test

In this example, material characteristics were analyzed to establish the molding conditions of the Cu/Al/Cu clad metal material. For the test, a universal testing machine (UTM) was used. The test speed was 1 mm/min before the yield point and 10 mm/min after the yield point. The test specimen was a KS B 0801 standard specimen, and the wire cutting was performed in three directions: Rolling Direction and 45° Transverse Direction.

As a result of the tensile test, the length of the specimen increased after the test compared to before the test, and fracture occurred after a certain period. Table 2 below shows the mechanical properties of the clad metal plate through a tensile test. The values according to the direction showed a similar trend with little deviation. The yield strength was at least 112 MPa to the maximum 118 MPa, and the maximum tensile strength was at least 177 MPa to 188 MPa.

Bending test

In this example, in order to evaluate the deep drawing property of a Cu/Al/Cu clad metal material, an experiment was conducted using an Ericsson deep drawing tester. The specimens used in the deep drawing test were sheared in a rectangular shape with a width of 90 mm and a length of 300 mm, and were coated with small oil (wooji) on both sides of the material to minimize friction between the material and the punch and die. The deep drawing test process is shown as shown in FIG. 8. When the previously prepared material is put into the deep drawing tester, it is automatically circularly sheared by the shearing mold and then immediately formed by a cylindrical cup punch. At this time, the test was conducted up to the diameter of normal molding while changing the tool from 63mm to 68mm in diameter.

The results of the deep drawing test are shown in FIG. 9, and the mold was successfully molded at a maximum moldable blank diameter of Ø60mm, and cracks and bursting phenomena occur during molding when molded into a blank having a diameter of Ø61mm or more. Punch diameter is Ø33mm, holding force is 2kN~3kN, Daiwa punch gap 2.5mm~3.0mm can be successfully formed, and LDR (Limit Drawing Ratio), an evaluation index of the deep drawing test of cylindrical cup, was confirmed to be 1.82. LDR is a value obtained by dividing the punch diameter by the maximum moldable blank diameter. The larger the LDR, the better the drawability.

Bending Repeat Test

In this example, in order to evaluate the bondability of Cu/Al/Cu clad metal material due to fatigue bending failure, a bending repeat test jig was prepared and the experiment was conducted. For fabrication of the bending repeat test jig, the wrap around bending test, a type of bending test, was referred to. The principle of the device is to determine whether the bonded interface is peeled off by visually observing the fracture surface of the material by repeatedly performing 90 degree bending> original position> opposite direction 90 degree bending> original position after mounting the specimen. At this time, it is designed to fix both ends of the material so that bending occurs repeatedly at a certain position. The test was carried out by shearing three specimens in a rectangular shape of 30 mm x 70 mm and bending 90 degrees until fracture occurred.

10 is a result of a bending repeated test. As a result of observing the fractured part of the specimen after the test, it was confirmed that peeling occurred locally at the bonding interface of Cu and Al. However, the result of this example is that peeling occurred by repeating bending several times for the purpose of observing the fractured portion of the specimen after fracture, and it will be performed once at a maximum angle of 90 degrees in the actual product bending process. Therefore, it is expected that there will be no peeling problem due to bending molding.

Springback measurement

In this embodiment, drawing molding was performed to check the degree of springback due to the elasticity of the material when forming Cu/Al/Cu clad metal. The drawing molding process for measuring the spring bag is shown in FIG. 11. For the test, the clad metal sheared to the size of 35mm x 400mm x 2.5mmT is pushed to the end of the die using a universal molding tester (UTM), and then formed into a square cup shape, and the specimen after stress is removed is 3D measuring machine. The amount of change was confirmed using. 12 is a photograph of a specimen after drawing molding for springback measurement.

13 is a springback measurement method. After the bending test, the amount of springback due to elastic restoration was quantitatively measured as the springback angle (θ1) according to the punch radius, the springback angle (θ2) according to the die shoulder radius, and the side wall curvature radius ratio (1/R). As the number of springbacks decreases, the springback angle (θ1) according to the punch radius and the springback angle (θ2) according to the die shoulder radius are closer to 90 degrees, and the sidewall curvature radius ratio (1/R) is closer to zero. The amount of springback can be measured in the CAD system after receiving data of points (X, Y) on a two-dimensional plane measured by placing the specimen on a three-dimensional measuring device and reading it from the CAD system.

Table 3 shows the springback measurement results. It was confirmed that the radius of curvature has a very large value or an infinite value, and the curvature is the reciprocal of the radius of curvature and has a value approximating 0. The springback angle (θ1) and the springback angle (θ2) according to the die shoulder radius were found to be close to 90 degrees.

V bending test

In this example, a V-bending test was performed to confirm cracking and peeling characteristics of the clad metal due to Cu/Al/Cu clad metal bending. 14 is a photograph of the universal material testing equipment and V-bending mold used in this test. The specimen used in this test was sheared from the clad metal to 20 mm x 70 mm, and the V bending mold was subjected to bending tests under four conditions of inner radius of curvature of 0,5, 1.0, 1.5, and 2.0. Evaluation was performed by visual inspection and SEM observation of the bending part after V bending.

15 is a result of a V bending test. As a result of visual inspection after V-bending, there was no crack, peeling, or change in appearance under the four conditions of the inner radius of curvature. Likewise, in the SEM observation result, no traces of peeling or other effects of the bonding interface of the Cu/Al layer were observed inside. Therefore, it was confirmed that the conditions of the inner radius of curvature of 0.5, 1.0, 1.5, and 2.0 of the bending part are not limited during product molding.

Molding limit test

In this example, in order to evaluate the degree of molding limit of Cu/Al/Cu clad metal, a molding limit degree (FLD) test was performed using a universal material tester and a strain measuring device. The molding limit diagram shows the values of the critical maximum circumferential form factor and the minimum circumferential form factor on the surface of the plate causing fracture on the maximum and minimum circumferential form rule planes. For the specimen, the material is first cut, printed in a 2mm x 2mm square grid on the material surface, and then wire-cut in accordance with the standard in the RD direction. The molding limit diagram (FLD) test process and principle are shown in FIG. 16. If this clad metal material is molded with a dome-shaped punch using a universal testing machine (UTM), the shape of the material's surface before/after square grid forming changes.At this time, the grid pattern analyzer It is to measure and draw the molding limit. 17A and 17B are clad metal materials before/after the dome mounting test.

By performing the FLD test, it was possible to obtain a successful molding limit without abnormal fracture of the Cu/Al/Cu clad metal. 18 is a graph showing the results of the dome mounting test using a strain measuring device (Grid Pattern Analyzer). When molding, the material is deformed and the shape of the square grid on the surface is deformed.At this time, the large value of the deformation is displayed in the coordinates of the maximum peripheral strain and the small value in the coordinates of the minimum strain is stably formed. FLC can be obtained from the possible safety points and the points where necking or cracking (bursting) of the material has occurred after molding. In general, Marginal FLC is composed of 5% and is shown in the graph of FIG. 18.

Molding analysis

In this embodiment, a molding analysis of a busbar for a clad metal film capacitor, which is one of the components of an inverter module of a hybrid vehicle under study in this project, was performed using Autoform to evaluate formability. This is the mold model used in the analysis. In the case of the busbar, the upper mold and the lower mold are required because it is molded with a progressive mold. As the subject of the bus bar is not currently confirmed, the existing YF bus bar was molded and analyzed as a previous study. Analysis was carried out under the conditions of 1st Flange bending> 2nd Flage bending> Cam restrike> Piercing> Spring back with press 300ton (Fig. 19). 20A to 20C show the forming process of the bus bar.

21 is a result of analyzing the crack generation area when the clad metal is molded into a bus bar shape, and FIG. 22 is a result of analyzing the wrinkle generation area. The thickness reduction point of the material appears to need to be reduced by about 5-10% at 3 places, and it was confirmed that it is located in the Safty section of the FLD diagram. When looking at the formability of the product, the shape of the product is simple, and it is a product that does not require large formability, and there is room for a problem in some sections, but it is relatively good compared to the FLD where the reference crack has occurred, so the formability is good. .

As a result of analyzing the spring back phenomenon after product molding (FIG. 23) shows that excessive spring back occurs in the bent portion, a side balance is required when forming a flange (up). In addition, in order to suppress springback, it is necessary to divide the flange molding 2 to 3 times and perform bending. Through the results of the molding analysis, the defective part could be predicted in advance.

Construction of an electrical conductivity measurement system to evaluate the performance of Cu/Al/Cu clad metal compared to Cu material

In this example, a method of calculating electrical conductivity by measuring the electrical resistance of a product was secured through ASTM B193-02 and IEC 60468 (Method of Measuring Resistivity of Metallic Materials), and a multi-automated electrical conductivity measurement system was designed. 24 shows a jig for measuring electrical conductivity. By manufacturing a dedicated jig, it is possible to measure contact defects or the same measuring point, so that measurement errors can be solved, and the electrical conductivity of various products can be measured by replacing them with a dedicated jig according to the product type. The electrical resistance was measured using a MI 3252 micro-ohm meter, and was manufactured to fix the product for measurement using pneumatic pressure (FIG. 24).

Performance evaluation according to bending, Cu layer peeling and cracking

In this example, the change in electrical conductivity according to the bonding characteristics of the clad metal, which is one of the important characteristics of the clad metal busbar, was evaluated. 25 shows the characteristics of a Cu/Al/Cu clad metal material. Cu has excellent electrical conductivity, but since it is clad by inserting Al between Cu plates to reduce weight, the conductivity will be relatively lower than that of a single Cu material. In addition, since it is a material in which different materials are bonded, the electrical conductivity of good and defective products was compared because there is a possibility of being affected by the electrical conductivity due to peeling or cracking of the bonding interface by molding. In order to calculate the electrical conductivity, the resistance measurement was performed using a MI 3252 microohm meter, and the current was 100A and the application time was 2sec.

By using a jig to measure the resistance value under the same conditions, the deviation according to the measurement distance was minimized when testing for defects in cracks and peeling of the interface layer of the bonding material and measuring electrical resistance. The specimen for resistance measurement is made of a clad metal material in the form of a long rod, and the length of the specimen must be 100 times or more of the square root of the cross-sectional area, and in this study, it was processed as 2mm x 350mm x 2.5mmT. The processed specimen was mounted on a jig, and current flowed from both sides (①: applied current) and clamped (②: resistance measurement) so that the material is well energized in a certain section between ① to measure the resistance.

The resistance was measured by preparing 5 clad metal materials used for resistance measurement, 5 materials obtained by repeatedly bending the material to crack or peel Cu, and 5 fracture specimens. Table 4 and FIG. 26 show the results of calculating the electrical conductivity by measuring the resistance of a good/defective clad metal material. The conductivity of the clad metal specimen with good and Cu cracks was averaged 70%IACS. On the other hand, the electrical conductivity of the specimen facing the fractured portion after complete fracture was an average of 49% IACS. In the case of the Cu cracked specimen, even if one side is locally peeled, the current flows smoothly to the opposite side of Cu, so it is considered that there is no difference between the good product and the conductivity. However, in the case of the fractured material, the Cu layer was completely shorted and the fractured material was brought into contact with the fractured material when measuring resistance, but the cladding metal of this study is Al 70% and Cu 30% (15% on one side), so the area occupied by Al is large It is thought to have decreased rapidly.

In addition, since the clad metal produced in the present invention is a material requiring heat resistance and corrosion resistance, thermal shock and salt spray tests were conducted. The thermal shock test was conducted for 400 cycles under the condition of 1 cycle (-40℃-1hr, 105℃-1hr) as the heat cylce test method, and visually inspected the visual appearance, and as a result of the inspection, no cracks or breakages occurred. The salt spray test was carried out for 48 hours under the condition of salt concentration (50±6.5 ~ 7.2, with KS D 9502:2009 (Neutral Salt Spray Test). After the test, no red rust occurred on the appearance when visually inspected.

27 and Table 5 are the results of measuring the conductivity before and after the thermal shock and salt spray test. The conductivity does not change at 70%IACS before/after thermal shock and salt spray test. This is considered to be because there was no damage to the exterior that could affect the conductivity. Therefore, the clad metal material of the present invention satisfies heat resistance and corrosion resistance, and since there is no change in conductivity under adverse conditions, it is determined to meet the application conditions.

The above description of the present invention is for illustrative purposes only, and those of ordinary skill in the art to which the present invention pertains will be able to understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting.

Claims (10)

First copper plate; Aluminum plate; And laminating a second copper plate (S1).
Rolling the plate material laminated in the step S1 (S2); And
Including the step (S3) of plating the rolled plate,
The plating step is a nickel plating step; And a method of manufacturing a hybrid wide plate, characterized in that carried out by a method comprising a tin plating step.
delete The method of claim 1,
The first copper plate, the aluminum plate, and the second copper plate are surface-treated by a brushing process, the method of manufacturing a hybrid wide plate.
The method of claim 1,
The first copper plate; Aluminum plate; And an intermetallic compound layer formed between the second copper plate, wherein the compound layer has a thickness of 0.001 μm to 3.0 μm.
The method of claim 1,
The rolling of step S2 is performed at a minimum reduction rate of 50% or more, and is performed at 200 to 450° C. or less.
The method of claim 1,
A method of manufacturing a hybrid wide-width plate, characterized in that using a rolling oil having a viscosity of 50 or less as a rolling oil for rolling in the step S2.
delete The method of claim 1,
The nickel plating is performed for 1 to 30 minutes at 52° C. with a voltage of 2.5 V and a current of 200 A,
The tin plating is characterized in that performed for 1 to 30 minutes at 15 to 35 °C with a voltage of 2.2V and a current of 160A.
Hybrid wide plate manufactured by the method of claim 1.
The method of claim 9,
The plate is 2.5t, characterized in that the width of 600mm or less grade, wide plate.

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