JPH0256192B2 - - Google Patents

Description

Detailed Description of the Invention Field of Application The present invention relates to a method for manufacturing a striped clad material in which Al or Al alloy strips are clad on a metal substrate by cold welding, and involves diffusion sintering after cold welding. This invention relates to a method for producing a cladding material that does not require annealing or strain relief annealing, has uniform internal strain in the width direction of the cladding material, and is prevented from deformation after etching or punching.

BACKGROUND ART Materials in which Al or Al alloy strips are clad entirely or in stripes on various metal substrates, such as 42% Ni--Fe alloy or Kovar alloy strip, are often used as materials for electronic components.

For example, in the production of Al striped cladding material, a metal substrate strip of 42% Ni-Fe alloy is annealed in a reducing atmosphere, the substrate surface is cleaned, and then the surface area to be cold welded is The substrate is buffed and cleaned, one or multiple Al strips in the desired pattern are stacked on top of each other and cold welded, and after welding or at least one cold rolling process, 600 Diffusion annealing treatment is performed at temperatures below ℃ to complete the bond between the Al strip and the metal substrate.Furthermore, cold rolling is performed at least once to adjust the dimensions and shape of the cladding material. In order to remove the internal stress strain that remains unevenly in the width direction of the substrate due to cladding or the residual strain at the edge after punching, heat treatment is performed at a temperature below 550℃, or heating is performed at 550℃ to apply tension to the clad strip. Generally, a manufacturing method is adopted in which the material is straightened by adding elongation and elongation.

Conventional manufacturing methods require a large number of steps and heat treatments, which increases manufacturing costs and increases the cost during diffusion annealing.
Problems include scratches on the Al and Al alloy surfaces and deterioration of surface quality.

Purpose of the Invention The present invention aims at a method for manufacturing striped cladding materials used in electronic component materials, which can omit the conventionally indispensable diffusion annealing process after cold welding, and can eliminate only the cold welding process. In addition, the adhesion of the Al material and the surface quality of the Al material are excellent.Furthermore, the internal stress of the metal substrate width method can be made uniform without strain relief annealing, and deformation after punching can be prevented. The aim is to develop a method for manufacturing cladding materials that can prevent this.

SUMMARY OF THE INVENTION As a result of various studies aimed at creating a manufacturing method for cladding materials that can omit the diffusion annealing process after cold press welding, the present invention has developed a method for manufacturing cladding materials that can omit the diffusion annealing process after cold pressure welding. By forming a hardened surface layer and cladding it with Al or Al alloy,
We discovered that the joint can be completed using only cold pressure welding, eliminating the need for conventional diffusion annealing treatment, and we have also applied this pressure welding method to clad materials for lead frames that have strict product shape and dimensional accuracy. As a result of various studies, we formed a concave groove on one main surface of the metal substrate, applied the above-mentioned specific buff polishing to the surface of the metal plate at the concave groove position on the other main surface opposite to the main surface where the concave groove was formed, and When Al or Al alloy strip is cold welded to the above-mentioned position, the internal stress in the substrate width direction is made uniform, and the above-mentioned diffusion annealing process and residual strain relief annealing process are unnecessary. Alternatively, they discovered that a clad material that does not deform after punching can be obtained by simply cold rolling after cold welding.

That is, the present invention provides a method for producing a clad material in which Al or Al alloy strips are clad on a metal substrate by cold pressure welding, in which a concave groove is formed on one main surface of the metal substrate, and the metal substrate is placed in a reducing atmosphere. After annealing, the surface of the metal substrate at the position of the concave groove on the other main surface opposite to the main surface where the concave groove is formed is buffed using a wire brush made of a metal wire with a clean surface that has a hardness higher than that of the metal substrate, and soft annealing is performed. A hardened surface layer having a hardness higher than the hardness of the metal substrate in the state and less than the hardness corresponding to the plastic limit is formed under the surface of the metal substrate with a layer thickness of 20 μm or less, and then Al or Al is applied on the hardened surface layer. This is a method for producing a clad material, characterized in that alloy strips are cold-welded at a reduction rate of 25% to 70%.

Structure and Effects of the Invention More specifically, the present invention provides a metal substrate having two smooth main surfaces, for example, a metal substrate with a 42%
Concave grooves equal to the cross-sectional area of the Al or Al alloy strips clad in the desired pattern are formed on one main surface of the Ni-Fe alloy or Kovar alloy by cold rolling in the same arrangement pattern. In order to remove residual strain, after annealing at 850℃ to 1050℃ in an inert atmosphere, the hardness of the metal wires arranged uniformly and radially around the entire circumference of the rotating drum is set to be greater than the hardness of the metal substrate to be polished. Then, with a wire brush using a metal wire with a clean surface, the opposite main surface on the side where the concave grooves are not formed is buffed, and as shown in Figure 2, the metal substrate in a soft annealed state is coated on the surface of the metal substrate. A hardened surface layer having a hardness ranging from hardness to the hardness corresponding to the plastic limit is formed with a thickness of 20 μm or less, and 25% of Al or Al alloy strip is formed on this hardened surface layer.
When cold welding is performed at a reduction rate of ~70%, cracks occur in the hardened layer, and the Al and Al alloy strips are pushed into these cracks during cold welding, making the welding complete. Diffusion annealing treatment is used to stabilize the joint, which was previously considered indispensable, by making the rolling reduction ratio uniform between the press-welded part of the Al alloy and other parts, and to remove the distortion caused by uneven rolling reduction ratio. is no longer necessary, the strain inside the clad material is made uniform, no deformation or distortion occurs in the product during subsequent punching or etching, and there is no need for strain relief annealing.

Disclosure of the Invention Based on Drawings FIGS. 1A, B, and C are explanatory diagrams showing a method for manufacturing a cladding material according to the present invention.

In the figure, concave grooves 2 equal to the cross-sectional area of Al or Al alloy strips clad in a desired pattern are formed on one main surface of a metal substrate 1 in the same arrangement pattern by cold rolling using forming rolls 3. , In order to remove the internal residual strain caused by the formation of the concave groove 2, the heating furnace 4 was heated in an inert atmosphere at 850°C to 1050°C.
The metal substrate 1 is annealed at ℃, unwound from the coil 5 after annealing, and then buffed with a wire brush roll 6, and Al or Al alloy 7 is applied onto the polished surface with a carbide roll 8. It shows a process of cold welding with a forged steel roll 9, and then winding it into a product coil 10 as a product clad strip.

In this invention, the metal wire used for the wire brush roll 6 preferably has an outer diameter of 0.1 mm to 0.5 mm;
In order to avoid contaminating the metal substrate, it is preferable to use a metal wire with a clean surface.The hardness of the metal wire is determined by taking wear resistance into consideration.If the metal wire has a hardness greater than that of the metal substrate 1, for example, carbon steel or stainless steel can be used. Any metal wire may be used, and a high-hardness wire is most preferable from the viewpoint of cost.

Obtained by buffing with the above wire brush,
In order to obtain a perfect cold welding effect, the surface hardened layer on the surface of the metal substrate needs to have a hardness higher than that of the metal substrate in the soft annealed state and less than the hardness corresponding to the plastic limit, and the layer thickness is 20 μm. The following is preferable; if it exceeds 20μm, the pressure welding effect will decrease,
This is not preferable because it may peel off in subsequent steps and the surface quality of the substrate will deteriorate.

In the cold welding process, the concave groove 2 of the metal substrate 1
The reason why Al or Al alloy 7 is not pressure-welded to the smooth surface of the opposite main surface is that lubricant is applied to the groove to prevent the metal substrate and Al or Al alloy from adhering to the pressure roll. This is because the particles invade, making it impossible to obtain a perfect pressure bond, and causing peeling or blistering in subsequent steps.

Although a forged steel roll may be used as the pressure roll, it is preferable to use a carbide roll 8, which has a rolling reduction ratio of 25
If it is less than %, sufficient pressure welding will not be performed and the
There is a risk that Al or Al alloy 7 may peel off, and if the reduction rate exceeds 70%, it will result in excessive reduction and cause cracks and cracks in the cladding material, which is undesirable, so the reduction rate in the cold welding process is 25%. ~70%.

If the amount of lubricant supplied is excessive, it may cause damage to the metal substrate.
It is undesirable because it invades the press contact surface of the Al strip, impeding the press contact effect, and after forming into a lump, causes partial peeling and minute blisters, resulting in a deterioration in product quality.

In addition, chlorine is used as an extreme pressure additive in lubricants, but if the chlorine content exceeds 20 ppm,
Chlorides are generated on the surface of the metal substrate and become oil stain, which impairs the surface quality of the metal substrate and Al strip.
The amount of chlorine contained is preferably 20 ppm or less.

In the cold rolling process, the rolls used include:
Carbide rolls may be used, but forged steel rolls are preferable, in order to adjust residual strain, adjust the dimensions and shape of the clad product, and prevent product deformation after subsequent punching or etching for commercialization.
Cold rolling is performed at least once, and the rolling reduction is preferably 1% to 20%.

Examples Example 1 42% Ni with a thickness of 0.4 mm and a width of 25 mm as a metal substrate
- An Fe alloy strip was used, and a 99.7% pure Al strip with a thickness of 0.010 mm and a width of 4.5 mm was used as the cladding material.

On one main surface of the metal substrate, 0.010mm depth x 5mm
A single width groove was formed in the center by cold rolling. Then, the metal substrate strip was heated in hydrogen at 850°C.
Annealing was performed for 2 hours.

Furthermore, the central part of the smooth main surface of the metal substrate without grooves was buffed using a wire brush with 0.3 mmΦ x 50 mm surface-clean high-hardness wires arranged uniformly in a radial manner on the entire circumference of the drum with an outer diameter of 100 mm. The metal substrate was polished to a depth of 18 μm from the surface to a hardness of 240 HV (hardness equivalent to plastic deformation) to 140 HV (hardness equivalent to annealed state).

Next, Al was applied on the surface hardened layer of the metal substrate.
The strips were cold-welded at a rolling reduction of 30%, and a chlorine-free lubricant was used during pressure welding to maintain the pressure roll surface at 50°C.

After cold welding, the alloy strip was cold rolled twice at a rolling reduction of 5% to obtain a clad product with a thickness of 0.250 mm and a width of 25 mm.

The obtained cladding material was heated at 530°C for 6 minutes in the air, and then an adhesive tape was applied to the Al surface, which was peeled off and the Al surface was observed under a 50x magnification microscope. No peeling occurred and the appearance was extremely good.

Example 2 The cladding material of the present invention obtained in Example 1 was subjected to the following etching process.

After cutting the material to a length of 150 mm, it was degreased by ultrasonic cleaning using acetone for 5 minutes.

Next, a resist was applied by screen printing using a comb-shaped printing screen, and then the resist was cured and dried in a constant temperature bath at 100° C. for 30 minutes.

Further, this was etched for 20 minutes at room temperature with a ferric chloride solution having a concentration of 42 Baume, and after eluting unnecessary parts, it was washed with water, dried, and then immersed in a trichlene solution to remove the resist.

The linear portions of the obtained etching samples (Fig. 3) using this invention material are 100 mm long x
It is 1mm wide x 0.25mm thick.

For comparison, using a metal substrate with the same material dimensions as in Example 1, an Al strip of the same dimensions was cold-welded to the smooth surface under the same conditions without providing a recessed groove.
Furthermore, the cold rolling of Example 1 was carried out to obtain a comparative clad material, which was subjected to the above etching process to produce an etched sample (FIG. 4).

Figures 3 and 4 are top and front explanatory views showing the product shape of the lead frame, and Figure 3 shows the case of the cladding material according to the present invention, with very little distortion at the edges and deformation of the Al cladding. In Although,
In the case of the cladding material manufactured by the conventional method shown in FIG. 4, the distortion at the edge portion and the deformation of the Al cladding portion are large and curved.

In other words, the clad material according to the present invention can omit diffusion annealing and strain relief annealing processes in the manufacture of products with strict shape and dimensional accuracy, such as lead frames, and is free from deformation after etching and punching. It is found that it is the most suitable material for lead frames because it has several advantages.

[Brief explanation of drawings]

FIGS. 1A, B, and C are explanatory diagrams showing a method of manufacturing a cladding material according to the present invention. FIG. 2 is a graph showing the relationship between the surface depth and hardness of a metal substrate.
Figures 3 and 4 are a top view and a front view showing the product shape of the etched sample. Figure 3 shows the case of the clad material according to the present invention, and Figure 4 shows the case of the clad material manufactured by the conventional method. . 1... Metal substrate, 2... Concave groove, 3... Forming roll, 4... Heating furnace, 5... Coil, 6... Wire brush roll, 7... Al or Al alloy, 8
... Carbide roll, 9 ... Forged steel roll, 10 ... Product coil.

Claims (1)

[Claims] 1. A method for manufacturing a clad material in which Al or Al alloy strips are clad on a metal substrate by cold pressure welding, in which a concave groove is formed on one main surface of the metal substrate, and the metal substrate is placed in a reducing atmosphere. After annealing in the inside, the surface of the metal substrate at the position of the concave groove on the other main surface opposite to the main surface where the concave groove is formed is buffed using a wire brush made of a metal wire with a clean surface that has a hardness higher than that of the metal substrate to make it soft. A hardened surface layer having a hardness higher than the hardness of the metal substrate in the annealed state and less than the hardness corresponding to the plastic limit is formed under the surface of the metal substrate with a layer thickness of 20 μm or less, and then on the hardened surface layer, Al or A method for producing a clad material, characterized in that Al alloy strips are cold-welded at a reduction rate of 25% to 70%.