JPH01104484A - Method for joining copper and copper alloys by rolling - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved rolling bonding method that can significantly improve the interfacial adhesion and shape stability of copper and copper alloys.

[Prior Art and Problems] When copper and copper alloys are pressed together by rolling, conventionally, after JUffff cleaning, the bonding surface is mechanically polished by brushing, puffing, shot blasting, etc. to form an active surface on the surface. Rolling and pressure welding has been practiced.

However, this mechanical polishing naturally increases the surface roughness, reaching a maximum surface roughness Rt of 8 to 200 μm. Even so, there was no problem as long as the thickness of the strips to be joined was thick.

However, recently there has been an increase in demand for composite metal strips made by overlapping extremely thin foils of 3 to 200 μm, and when these are bonded using the conventional method, the thickness is almost the same as the surface roughness mentioned above, and the foils tend to tear. It was difficult to obtain a composite material with a uniform coating thickness.

Furthermore, due to the above-mentioned surface roughness, microscopic air entrapment occurs during overlapping rolling and pressure welding, resulting in unbonded areas. Then, during the subsequent diffusion heat treatment, the unbonded portions would become blistered, causing deterioration of the surface quality.

Therefore, in order to obtain high quality ultra-thin coated composites, it is desirable not to use the mechanical polishing.

For this purpose, as pretreatment, vacuum annealing at 10' torr, annealing in an argon inert atmosphere, and surface reduction annealing are performed in separate processes, and this is carried into the rolling pressure welding process. There is also a method of rolling and pressure welding without performing the mechanical polishing. However, in this case, it is difficult to ensure stable adhesion unless the rolling rate is higher than 70%.
Providing such a large rolling blade causes extreme end elongation, which poses a problem in that it becomes difficult to obtain a composite metal strip that is stable in shape and quality.

[Object of the Invention] The present invention aims to eliminate the above-mentioned drawbacks of the prior art and provide a method for obtaining a composite metal strip made of high-quality copper and copper alloy with stable adhesion.

[Summary of the Invention] That is, the gist of the present invention is to reduce the surface of copper and copper alloy by heating and reducing the surface at high temperature for a short time on the same line to activate the surface, and also to perform annealing treatment at the same time.
Subsequently, it is cooled on the line and then rolled and pressure-welded as it is, thereby making it possible to obtain a composite metal strip with excellent adhesiveness and shape stability without mechanical polishing.

[Example] The present invention will be explained below based on examples.

FIG. 1 is a schematic explanatory diagram showing how the method according to the present invention is performed. 1.1' is a coil-wound raw material, 2
3 is a reduction furnace, 3 is a cooling chamber, 4.4 is a rolling roll, 5 is a winding machine, and 10 is a composite metal and metal strip.

In the present invention, as shown in FIG.
A major feature is that cooling and rolling are all performed on the same line. That is, if the reduction treatment is performed in a separate line, the contact time with the atmosphere becomes longer, moisture is adsorbed on the activated surface, and oxidation progresses, making it impossible to obtain stable adhesion. In particular, in the case of a coiled material, the reduced surface is likely to be contaminated by the roller or by the operator's fingers, which becomes a factor that inhibits stable adhesion.

In the present invention, the mechanical polishing as in the conventional example is not carried out, but instead a high-temperature and short-time heat treatment is carried out in the reduction furnace 2 to reduce and activate the surface. I will also do better. However,
The atmosphere in this reduction furnace is preferably reduced by high-temperature hydrogen gas G, and the temperature is preferably in the range of 500 to 1040°C.

In other words, Figure 2 is a line plotting the relationship between the reduction temperature, reduction time, and the area where good adhesion is possible by rolling pressure, assuming that the reduction weight loss (percentage of weight change before and after reduction) due to hydrogen reduction is 0.1%. It is a diagram. According to this, when the reduction temperature becomes 500° C. or less, the reduction time becomes considerably longer, and good rolling pressure welding is inhibited. Therefore 500
Temperatures below ℃ are excluded. Regarding the upper limit, the higher the temperature, the faster the reduction, which is preferable, but the upper limit is limited to 1040° C. in relation to the melting point of copper.

It was also found that no significant difference was observed in such a temperature range even under reducing atmospheres other than hydrogen gas.

Surface activation is achieved by the above surface reduction, but the maximum surface roughness Rt in that case is 1.5 to 20 μm, and the Rt of the mechanical polishing is
= 8 to 200 μm, it can be seen that it is much smaller. For this reason, it is possible to prevent microscopic air entrapment even during overlapping rolling welding, thereby eliminating the existence of unbonded parts, making the metallurgical bond strong, and making it easier to use during the subsequent diffusion heat treatment. This is to eliminate the occurrence of fire bukure.

After performing the above-mentioned thermal reduction treatment, the surface-reduced material is passed through the cooling chamber 3 and cooled to 100° C. or lower. Figure 1 is only a schematic diagram, and cooling with water W is illustrated, but this cooling method is a method that cools the temperature to below 100°C in a short time and does not have any adverse effect on the reduction-activated surface. It's not something I'm particularly concerned about. However, it is desirable that the cooling temperature is 100°C or less at the stage of rolling and welding by the rolling rolls 4, 4, and if the temperature is higher than this, sufficient adhesion may be inhibited. . In other words, when copper and copper alloys are brought into contact with the atmosphere, an oxide film is formed, but if the temperature at that time is 100°C or less, the film thickness will increase to about 20A° in a few minutes, and it will last for 1 hour. Even after that, it is as small as about 40 A°, and the composition of the oxide at that time is again Ctlz○, so it does not have a large effect on adhesion.

However, when the temperature exceeds 100° C. and reaches about 256° C., the thickness of the oxide film increases rapidly on the cube side, and the oxide produced at that time is CuO, which becomes a factor that inhibits adhesion.

Therefore, before rolling and welding, the temperature of the material is set to 100℃ or less,
It is desirable to suppress the oxide film thickness.

Depending on the thickness of the materials to be welded, processing history, or rolling reduction rate, there are cases where sufficient adhesion can be achieved with just the above-mentioned pressure welding, but when it comes to materials, especially pure copper, it is difficult to bond at temperatures around 40°C lower than the melting point, i.e. at temperatures below 1040°C. It has been found that the bond can be made extremely strong by diffusion heating.

This diffusion does not necessarily have to be carried out in the same line, and may be performed in a separate process, but if it is included in the same process, a large amount of labor can be saved. 3 is a schematic explanatory diagram showing the case where the manufacturing method according to the present invention is applied to rolling pressure welding of a three-layer composite metal strip, and 1.
1' and 1'' are the raw material, 2 is a reduction furnace, 3 is a cooling chamber, 4.4 is a rolling roll, 5 is a winder, and 6.6 is a guide roll.

In this process, the three-layer composite metal strip 10' is guided through the reduction furnace again, and diffusion heating is performed on the same line by this repassage, so that all the three-layer composite metal strips 10' are passed through the same line. As a result of the above steps, the effect of labor saving and cost reduction achieved is extremely large.

Example 1 Using a reduction furnace installed on a rolling and welding line as shown in the schematic diagram of Fig. 1, pure copper (OFC) with a width of 100mm and a thickness of 1.0WII11 and a width of 100mm and a thickness of 0.8mm was used. cu-
o, os%Ag alloy was subjected to reduction treatment at a temperature of 800° C. in a hydrogen stream, passed through a water cooling chamber, and then rolled and welded at a rolling ratio of 50%. At this time, a rolling mill with a work roll diameter of 180 mm was used.

Also, the surface temperature of the metal strip at the outlet of the reduction furnace was 80°C. As a result, sufficient adhesion was achieved, and the reduction ratio was reduced by about 10% compared to the conventional method in which the bonded surfaces were subjected to mechanical polishing.

Further, even when heat treatment was performed at 700° C., which served as both diffusion heating and annealing treatment, no fire blistering occurred.

Example 2 - Using a combined process of a reducing furnace on the same line as shown in Figure 3 and a rolling mill with a work roll diameter of 180 mm for rolling pressure welding, Cu-15%Ag- was applied to both surfaces of pure copper. Each plate combined with 5% P alloy [phosphorus copper solder] has a thickness of 2 Onw and a width of 10
A three-layer structure fabric made of 0M was reduced at a temperature of 600° C. in an ammonia decomposition gas (75% Hz, 25% Nz) atmosphere, cooled, and then rolled and welded. Stable adhesion was obtained at a rolling rate of 50%. On the other hand, the obtained three-layer composite metal strip was inserted into the same reduction furnace from the side opposite to the material strip, and a diffusion heat treatment was performed at the same time to strengthen the metallic bond, but there was no occurrence of fire cracking. Good adhesion was obtained.

Note that the surface temperature of each material strip at the outlet of the reduction furnace was 60°C.

Example 3 A manufacturing process with a reduction furnace and a rolling mill (work roll diameter 180 mm) as shown in the schematic diagram of Fig. 1 was used to produce a plate with a thickness of 2.0 mm.
, phosphor bronze (CU-3%sn alloy) with a width of 100B, and pure copper with a plate thickness of 20 mm and a width of 100 mm at a temperature of 650
After reduction with ammonia decomposition gas (75% H2, 25% Nz) at .degree. C. and cooling, the material was rolled and welded at a rolling ratio of 60%. At this time, the surface temperature of the material at the outlet of the reduction furnace was 50°C. Further diffusion heating at 500° C. resulted in a thinly coated composite material with strong adhesion and a coating thickness of approximately 8 μm (pure copper) without any swelling or blistering in unbonded areas.

In addition to the pure hydrogen and ammonia decomposition gas shown in the examples of the present invention, the atmospheric gas in the reduction furnace may include carbon monoxide gas or propane (exothermic gas, gas composition generated from 10 to 16% propane + air). As for 12-15%C
0.12-16% H2.

4 to 6% CO2, 2% H20, balance Nz) or a mixed gas of pure hydrogen, argon (Ar), and nitrogen gas may also be used.

On the other hand, as copper alloys, in addition to the examples of the present invention, chromium copper (CIJ-0.6%C "alloy"), zirconium copper (C
tl-0,15%zr alloy), beryllium copper (Cu-0
, 6%Be-2,5%CO alloy), tellurium copper (C(j-
0,5% Te alloy) phosphorous deoxidized copper (Cu-0,03% P alloy) red copper (Cu-10% Zn alloy) and phosphor bronze (C
It can also be applied to U-5% Sn alloy).

[Effects of the Invention] As detailed above, according to the rolling joining method according to the present invention,
The following excellent effects can be achieved.

(1) Coating thickness of 1 to 30μ for copper and copper alloys
A cladding material with a uniform thin coating layer of m can be easily produced.

(2) Although it has reduction furnace equipment, it is a simple process that does not generate dust generated by mechanical polishing, etc., and it is possible to manufacture composite metal strips with relatively flat joint surfaces.

(3) Annealing treatment is possible at the same time as reduction, which reduces deformation resistance, and because it is rolled and pressed immediately, stable and strong adhesion can be obtained.The manufacturing method is suitable for quick production, and has great industrial effects. Furthermore, since annealing is performed at the same time, the rolling load during pressure welding is also reduced, and a flat plate shape can be easily obtained.

(4) The phenomenon of fire blistering caused by conventional methods can be prevented, and a composite material with stable surface quality can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram showing the method according to the present invention being implemented, Fig. 2 is a diagram showing the relationship between reduction temperature and time, and Fig. 3 is a diagram showing the implementation of another method according to the present invention. FIG. 1.1', 1'': Raw strip, 2: Reduction furnace, 3: Cooling room, 4: Rolling roll, 5: Winding machine, 10.10': Composite metal strip. Agent: Patent attorney Fujio Sato 1 Figure 1.1', J": prefectural article 2: ilF,, f 3: meeting master φ; 5ItO-rero: pigN5. #jl! Figure 3

Claims (4)

[Claims] (1) Copper and copper alloy to be joined by rolling at 500℃
A method for joining copper and copper alloys, in which a surface reduction treatment is performed in a temperature range of ~1040°C, and the surface temperature of the materials is cooled to 100°C or less in the same line, and then rolled and welded. (2) Copper and copper alloy to be joined by rolling at 500℃
A method for joining copper and copper alloys, which comprises performing a surface reduction treatment in a temperature range of ~1040°C, cooling the surface temperature of the materials to 100°C or less in the same line, rolling-pressing them, and then heating and diffusing them at a temperature of 1040°C or less. (3) The joining method according to claim 1, wherein the surface reduction treatment is performed in an atmosphere containing high temperature hydrogen. (4) The joining method according to claim 2, wherein the surface reduction treatment is performed in an atmosphere containing high temperature hydrogen.