JPH02155581A - Production of clad material of copper and iron or nickel alloy - Google Patents

Abstract

PURPOSE:To make mass production of the clad material of a copper or copper alloy and an iron or nickel alloy at a low cost by interposing an aluminum powder layer between the base metal consisting of copper and the iron or nickel alloy, hot rolling and then diffusion annealing. CONSTITUTION:An aluminum sheet 3 is positioned to face the base material 1 consisting of the copper or copper alloy and is rubbed by a stainless steel wire brush 4 so that the peeled aluminum powder is rubbed into the surface of the base metal 1. The cladding metal 2 consisting of the iron alloy or nickel alloy is imposed thereon. The base metal 1 and the cladding metal 2 interposed the aluminum powder are hot rolled by using a heater 5 and a rolling mill 6. The metals are then diffusion annealed in heating furnaces 7, 7'. The clad material of the copper or copper alloy and the iron or nickel alloy is mass-produced at the low cost in this way.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to manufacturing a clad material, particularly a plate-shaped clad material (clad plate), made of copper or a copper alloy and an iron-based alloy or a nickel-based alloy. Regarding how to.

(Prior Art) Many types of cladding materials, which are made by layering different metal materials, are known and have been put to practical use in many fields by taking advantage of their respective characteristics. Copper (here, in addition to industrial pure copper,
Clad materials made of copper alloys (including copper alloys containing alloy components, also referred to simply as "copper") and iron-based alloys or nickel-based alloys are one example. For example, copper and stainless steel crand plates are used as materials for cooking utensils, and , Copper and Fe-42χNi alloy cladding materials are used as materials for electronic components such as lead frames.

As mentioned above, there are many proposals for manufacturing methods for cladding materials depending on the type of cladding material. However, cladding materials of copper and iron-based alloys or nickel-based alloys (rCu
-Fe(Ni) clad material) has a low diffusion coefficient and oxidation of copper is significant when heated in the atmosphere, so no manufacturing method has been established to mass-produce it at low cost. - For example, in joining by cold rolling, it is essential to completely remove the contamination (oxidation) layer on the joining surface, and even then, 6
Strong pressure such as 0% or more is required. Such strong pressure not only limits equipment capacity, but also poses the problem of difficulty in controlling the shape of the product clad material. On the other hand, soo
Warm rolling at a temperature of about is required, making it unsuitable for actual production.

Note that JP-A-54-94456 describes a copper-Al-stainless steel multilayer cladding material and a method for producing the same, which uses Al as one of the constituent materials of the cladding material of the final product. This is completely different from the cladding material targeted by the present invention, that is, the Cu-Fe(Ni) cladding material without an AQ layer.

(Problems to be Solved by the Invention) The present invention has been made with the aim of developing the most rational method for manufacturing Cu-Fe(Ni) cladding material, and it The purpose of the present invention is to provide a manufacturing method that employs a warm rolling method that does not require oxidation of the copper surface, and that does not have the problem of surface oxidation of copper as described above.

(Means for Solving the Problems) The present applicants have invented a manufacturing method in which aluminum powder is brought into close contact with the surface of a stainless steel plate and this is used as a bonding medium when manufacturing a clamp material of aluminum and stainless steel. and filed a patent application (Japanese Unexamined Patent Publication No. 50-73867)
The invention is based on the fact that since one of the constituent materials of the cladding material is aluminum, the same aluminum powder is used as the bonding medium.

After repeating numerous prototype tests, the present inventor surprisingly discovered that the use of aluminum powder has an excellent effect on the production of Cu-Fe(Ni) crund material that does not use aluminum as a constituent material. The present invention was made based on this knowledge.

The present invention relates to a method for producing copper characterized by ``warm rolling with an aluminum powder layer interposed between a base material of copper or copper alloy and a composite material of iron-based alloy or nickel-based alloy, followed by diffusion annealing. or a method for manufacturing a cladding material of a copper alloy and an iron-based or nickel-based alloy.''

Here, the base material copper or copper alloy refers to industrial pure copper and, for example, 40χCu-60χNi, 70χCu-
Cu-Ni like 30χ old, 90Cuχ-10χNt
copper alloys and other copper alloys. In addition, iron or nickel alloys (these are referred to as "laminated materials" in the present invention) include, for example, stainless steel, Fe-Ni alloy,
Ni-based alloys and pure nickel are used.

In the case of materials that are difficult to join with only - warm rolling and diffusion annealing, - warm rolling and sales expansion annealing (in this case, low temperature annealing is sufficient), then warm or cold rolling again. However, it is desirable to perform diffusion annealing.

1 and 2 are diagrams for explaining the main steps of the method of the present invention, and FIG. 2 shows an example of reversing rolling and annealing.

First, the process shown in FIG. 1 will be explained.

■ Process of attaching aluminum powder: There are various methods of interposing aluminum powder at the interface between the base material and the composite material, but the most practical method is to degrease and clean the surface of the base copper plate 1 and then apply aluminum powder on top of it. This is a method of attaching. Aluminum I5) powder has a particle size of pure aluminum of 10
A thickness of approximately 50 μm is preferable. This can be done by placing separately prepared powder on the surface of the base material, but as shown in the figure, place the aluminum plate 3 facing the base material surface, and make the surface of the stainless steel plate. A practical method is to rub the exfoliated powder with the wire brush 4 to rub it onto the surface of the base material. According to this method, the aluminum powder scraped off from the aluminum plate with a wire brush is immediately rubbed onto the surface of the base material, resulting in a so-called baked-in state. The aluminum powder layer attached to the surface of the base material in this state becomes more uniform and dense than when the powder is simply placed on the surface of the base material (↑5), and is more effective in suppressing copper oxide formation on the surface of the base material, which will be described later. can be prevented.

In either method, the aluminum $5) powder may be uniformly distributed on the surface of the base material to a thickness of about 4 to 7 μm.

■ Warm bonding rolling process Apply laminating material 2 to the surface where aluminum powder has adhered! This is a step of heating at Lt and warm rolling. For example, the material is heated to a temperature in the range of about 400 to 600° C. with a heating device 5 such as a high frequency induction furnace, and then rolled with a rolling mill 6. The surface of the base material is covered with aluminum powder, and since this aluminum powder prevents the surface of the copper base material from oxidizing, heating can be performed in the air.

The rolling is performed at a reduction rate of 20% or more per pass, preferably 25% or more.The rolling mill 6 is a two-stage or four-stage rolling mill.
A multi-stage rolling mill can be used. Bonding is basically completed in one pass, but rolling may be performed in multiple passes depending on the purpose of adjusting plate thickness or other purposes.

Note that if cold rolling, which will be described later, is not performed, the rolling reduction rate is determined here so that the final target thickness of the product is achieved.

A microscopic photograph (400x) of the interface between the copper base material and the composite material at the end of this rolling process is shown in (a) in Figure 3. are aggregated and scattered at the interface, and diffusion has progressed slightly between the base material and the composite material, resulting in a bonded state.

Note that although a portion of the aluminum is oxidized to become Afz (h), this does not pose any obstacle to diffusion and bonding.

■ Diffusion annealing process: This process promotes diffusion between the base material and the mating material to ensure sufficient bonding. Like the process in Figure 1,
If diffusion annealing is to be completed in one time, it is desirable to perform the following two-step process.

First, heating is performed for 60 to 90 minutes at a temperature of about 400 to 550°C (low-temperature diffusion annealing) to diffuse most of the aluminum powder scattered at the interface into the base material and the composite material. After that, in order to further promote the diffusion of the aluminum powder and to strengthen the bond between the base material and the laminated wood,
Annealing (high temperature diffusion annealing) is performed at 0 to 1000'C for about 10 to 30 minutes.

The heating furnace 7 shown in FIG. 1 is the above-mentioned low-temperature diffusion annealing furnace, and 7° is the furnace for high-temperature diffusion annealing.

There are no particular restrictions on the type of these furnaces.

After completing this process, the interface between the base material and the composite material can be discerned, but the aluminum powder has almost completely disappeared. FIG. 3(B) is a microscopic photograph of the interface after this diffusion annealing process has been completed.

The aluminum powder diffuses into the base material and the composite material and disappears.

It can also be shipped in this state as a clad material product.

■ Cold rolling and other processes: These are processes that are carried out as necessary, for example, to modify the shape or adjust the thickness of the cladding material.

Furthermore, additional processes such as surface treatment for rust prevention etc. may be required.

The process shown in Fig. 2 is an example in which after warm bonding rolling (1), diffusion annealing (2) is performed at a relatively low temperature, followed by re-rolling (2°) and diffusion annealing (2°). Recommended when thin clad products are required as shown below.Also, by dividing the rolling and annealing steps in the process shown in Figure 1 into multiple steps, there is the advantage of reducing the load on each process. .

Since the annealing of ■゛ is performed later by diffusion annealing ■゛° at a high temperature, the conditions of the low temperature annealing described earlier, i.e. 400~600
Heating at 0'C for about 60 to 90 minutes is sufficient.

(2) Re-rolling is performed either by reheating to about 300 to 550°C with a heating device of 5° to perform warm rolling, or by cold rolling at room temperature. In this rolling, metals having different elongation rates are basically rolled at the same time, so it is necessary to suppress the occurrence of shape defects such as warpage and reduction, so the total rolling reduction ratio is preferably about 50% or less.

Note that when rolling in this step is performed warmly, the reheating before rolling may also serve as low-temperature annealing. In this case, the reheating conditions are adjusted to the low temperature annealing conditions.

After this re-rolling, annealing is performed under the same conditions as the high-temperature diffusion annealing in the previous step ■.The high-temperature annealing in this case also plays the role of recrystallization annealing.Re-rolling and high-temperature annealing are required thereafter. You can repeat as many times as you like.

In the method of the present invention comprising the above steps, surface oxidation of the copper base material is prevented by the aluminum powder, so heating can be carried out in the atmosphere and the difficult problem of sealing the heating furnace is eliminated. Further, since the joining rolling is performed at a warm temperature, sufficient interfacial joining can be achieved without the need for heavy rolling at the ViA end.

The reason why a crund material with good interfacial bonding properties can be obtained by the method of the present invention without taking any special oxidation prevention measures is considered to be as follows.

Originally, copper has a strong affinity with oxygen, and in the atmosphere
Even when heated at a low temperature of about 1000 yen, a thick oxide scale is formed in a very short time of about 30 seconds. This oxidation scale (C
ub) is highly ductile, and when rolled, it spreads into a thin film on the surface and prevents bonding with other metals.

The use of aluminum powder in the present invention prevents the formation of such copper oxides. Ap, O, formed by oxidation of aluminum are hard particles, and even if they spread at the interface between the base material and the composite material during rolling, the particles will only be dispersed and will not form a film, and the atoms between the two materials will be dispersed. does not inhibit the diffusion of Furthermore, aluminum has a high diffusion ability into copper, iron, nickel, etc., and disappears from the interface during the annealing process described above, so there is no fear of separation between the base material and the composite material due to the presence of foreign matter at the interface.

(Example) JIS C1020 oxygen-free copper (base material) and JIS 511S304 stainless steel (laminated material) under conditions not shown below.
A crush plate was manufactured by the second leap process described above.

Base material size: 1.2tX150wX300I! (mm
)ii, Size of laminated material: 0.5tX150wX40
0ff (mm) 1■, Aluminum powder adhesion: JIS Al100 pure aluminum temporary (ff 0.5
mm) was placed on top of the base material as shown in Figure 2 and rubbed with a stainless steel wire brush to uniformly adhere to the surface of the base material to a thickness of approximately 5 μm.

Bonding pressure between iv and /M A stainless steel laminated plate was stacked on the base metal copper plate to which the conylminium powder was attached, heated to 400'C x 30 minutes in a high frequency v:I induction heating furnace in an air atmosphere, and rolled in two steps. It was rolled at a rolling speed of 10 m/min. The rolling reduction at this time was 25%, and the rolling bonding was carried out in the (2) pass.

(2) Low-temperature diffusion annealing: Annealing was performed at 400'C for 1 hour in an electric furnace in an air atmosphere.

(2) Re-rolling: After the annealing in (1) above, re-rolling was performed immediately (before the temperature dropped). A two-high rolling mill was used, the rolling speed was 1011/min, and the rolling reduction was 15% in one pass.

vi. High-temperature diffusion annealing: Annealing was performed at 1000°C for 15 minutes in an electric furnace in an air atmosphere.

Information, cold rolling: 4. It was rolled at a rolling speed of 30 m/min using the coldest rolling mill.

The rolling reduction rate was about 10% per 1 bath, and the total rolling reduction rate was about 50%. At this stage, no problems such as separation between the base material and the composite material occurred.

The clad plate manufactured under the above conditions had a reduction ratio of 25% during warm bond rolling and a reduction ratio during re-rolling of 25%,
Although it was relatively small at 15%, the bond between the base material and the composite material was perfect.

For comparison, we tested the same manufacturing method as in the example without attaching aluminum powder, and the heating atmosphere was changed to O! = 0.1%, an interfacial bond of the same level as that obtained by the method of the present invention was obtained.

(Effects of the Invention) The method for manufacturing a cladding material of the present invention requires only a simple step of interposing aluminum powder at the interface between the base material or the laminated material, and by adjusting the atmosphere during heating and during joining rolling. No special large pressure is required. According to this method, cladding materials of copper or copper alloys and iron-based alloys or nickel-based alloys, which have conventionally been difficult to mass-produce, can be mass-produced at relatively low cost.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing an example of the method for producing a cladding material of the present invention, and FIG. 2 is a process diagram showing another example of the method for producing a cladding material of the present invention. Figure 3 is a micrograph (x400) showing the metal &lIa at the interface when a cladding material of copper and stainless steel is produced by the method of the present invention, (a) is after warm rolling;
(b) is after diffusion annealing. The lower part of the photo (darker color) is copper, and the black interface in (a) is aluminum.

Claims (2)

[Claims] (1) Copper or copper characterized by warm rolling with an aluminum powder layer interposed between a base material of copper or copper alloy and a composite material of iron-based alloy or nickel-based alloy, followed by diffusion annealing. Method for manufacturing alloys and cladding materials of iron-based or nickel-based alloys. (2) Copper or a copper alloy and an iron-based or nickel-based alloy characterized in that a step consisting of rolling and diffusion annealing is added one or more times after the diffusion annealing in the manufacturing method according to claim 1. Method of manufacturing cladding material.