JPS58112682A - Manufacture of clad band - Google Patents

Abstract

PURPOSE:To obtain an Al stripe clad band which never generates a blister even when heated, by rolling a streak of Al on a base material at a prescribed rolling and reduction rate without using a rolling lubricant. CONSTITUTION:A steel roll whose surface is treated by a baking reduction treatment through hard Cr plating or immersion sulfate nitriding, or a roll made of sintered alloy which is less baked is used. Then, Al or a streak of Al alloy is rolled on the base material at cold or hot temperature at a 6-40% reduction rate without using any rolling lubricant. Thus, the Al stripe clad band is obtained, which never generates a blister even when heated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing metal cladding materials, particularly aluminum striped cladding strips.

BACKGROUND ART Striped cladding of aluminum or aluminum alloy (hereinafter referred to as "aluminum") on various metal base materials is used as a material for electronic components such as lead frames of ICs and LSIs.

Hitherto, the production of aluminum striped clad strips has been carried out in a conventional manner. In other words, the parts of the base material strips to be clad (and if possible, the mating surfaces of the aluminum strips) are polished and cleaned using a wire brush, etc., and then stacked together and then cold-rolled. The bonding is completed by crimping and diffusion annealing, which involves heating to a temperature of 300 to 600° C. for a short period of time. Thereafter, it is finished to a predetermined thickness by cold rolling.

However, when the cladding material is attached to a glass (including ceramics) sealing alloy base material, which is an important application of the aluminum striped clad strip, the cladding material must be heated to a temperature of about 500℃ or higher for sealing. At that time, fine flakes may form on the aluminum cladding, and partial peeling may occur. This often reduces the acceptance rate of the final product, so there is a need to provide cladding bands free of these defects.

According to the present inventors, the causes of the above-mentioned bags are:
The lubricating oil used to prevent seizure during cold rolling crimping has been scattered and penetrated between the base metal and the aluminum strip, partially interfering with rolling crimping and remaining in that area. Then, upon subsequent heating, it decomposes, vaporizes, and expands. However, until now, there have been no effective measures to prevent fleas.

The present invention has been made with the intention of overcoming such problems, and is made by cladding aluminum strips in stripes on a base material by cold rolling and crimping to form an aluminum stripe clad band. In the manufacturing method, steel rolls with hard chrome plating or sulfur-nitriding treatment to reduce seizure are used, or cemented carbide rolls with low seizure resistance are used, and rolling lubricants are not used. The method is characterized by performing rolling crimping at a reduction rate of 6 to 40 inches,
This makes it possible to provide an aluminum cladding that does not blister even when subsequently heated.

When performing the above-mentioned rolling crimping, the surface of the roll should be cleaned and
Immediately removing aluminum debris that may settle on the surface is effective in preventing seizure and is a recommended practice.

To explain with reference to the drawings, the base material 1 is unwound from the coil, unrolled, the surface to be cladded is polished and cleaned with a wire brush 6, etc., and the aluminum strips 2 cut out from the coil are stacked and rolled. Both positives are rolled and crimped using rolls 5A and 5B to form a clad band 3, which is then wound into a coil.

Since this rolling crimping does not use rolling lubricating oil, it can be carried out not only cold but also warm. In that case, the atmosphere is kept non-oxidizing if necessary.

If the rolling reduction ratio is not 6% or more, crimping will be incomplete.
The higher the value, the more sufficient the pressure bonding will be, but the tendency for the roll to seize increases and there is also the problem of work hardening.
Around 5 inches would be appropriate.

Among the surface treatments for roll materials, hard chrome plating is easy to implement, but in terms of anti-seizure effect, sulfur-nitriding, which is a troublesome process, is superior. Cemented carbide exhibits similar performance to sulfonitrided materials, but the material itself is expensive and not easy to process, making it difficult to make large rolls. Taking these advantages and disadvantages into consideration, rolls and rolling reduction ratios suitable for the rolling crimping to be performed should be selected.

The cleaning of the rolling roll is carried out on the rolling exit side of the roll 5A, which comes into contact with the aluminum, using a cloth puff 7 or the like that is not coated with an abrasive. (On the entry side of rolling, aluminum scraps get caught up in the rolls.) The inventors of the present invention observed the seizure situation in detail and found that the edges of the aluminum strips were slightly peeled off and adhered to the rolls. As the roll rotates, it comes into contact with the following aluminum strip, and a lot of aluminum adhesion occurs, increasing like a snowball and depositing dots on the roll. Knowing that this was the case, he tried and succeeded in preventing the growth of adhesion by removing it immediately if it occurred.

According to the present invention, the use of rolling lubricating oil can be eliminated in the production of clad strips, which previously had to employ a strong reduction rate of 50 inches or more in order to prevent incomplete crimping caused by rolling lubricating oil. Since it was possible to stop the process, sufficient crimping can be obtained with a low to medium rolling reduction of 6 inches or more and 40 inches or less.

As a result, the rolling reduction rate is normal for the rolling back die, and the tamper is 25 ~
Those designed to provide a reduction of 35% can be used, with the advantage that no specialized equipment is required.

In addition, when it is desired to suppress work hardening, a low rolling reduction ratio of 10 to 15%, which is described as preferable above, can also be adopted. As is known in the art, when work hardening is significant, annealing is required after rolling, but during this annealing progresses into the base material of aluminum, forming a brittle Fe-Al compound. An undesirable situation occurs. However, as a result of achieving sufficient crimping even at a low rolling reduction rate, the above problem was resolved.

In addition, when carrying out the method of the present invention, diffusion annealing and finish cold rolling are not required in order to completely bond the aluminum striped clad band and make the thickness the desired value. It would be necessary.

Of course, the conditions may be in accordance with known techniques.

It has been confirmed as follows that in the aluminum striped clad strip produced according to the method of the present invention, the adhesion between the base material and aluminum is improved on average. In other words, when we compare diffusion annealed cladding material by corroding it with caustic powder to remove aluminum and examine the dark coloring caused by the Fe-Al compound produced by diffusion, the conventional material has strong shading. , tb There are areas where there is strong adhesion and areas where there is weak adhesion or no adhesion at all, whereas according to the present invention, average adhesion is achieved with dark and light shades across the entire surface. I can see that it is true.

Example 1 42% Ni − glass sealing alloy as base material
A Fe strip with a thickness of 0.5wm and a width of 81cm is used, and pure aluminum (JIS 1070 equivalent) is used as the cladding material.
Using three strips with a thickness of 12 μm and a width of 4.6 m, each strip was clad at the center in the width direction of the base material and at a position of 37.5 − on both sides from the center.

After cleaning the parts of the base metal in contact with the aluminum by polishing with a wire brush, the aluminum strips were overlapped and rolled and crimped at various rolling reductions within the range of 4 to 50% without using rolling lubricating oil.

As a rolling roll, bearing steel (J I
A pair of rolls made of 5SUJZ (equivalent product) is adopted, one set is used with the polished surface, one set is hard chrome plated after polishing, and the other set is subjected to sulfur-nitriding treatment after polishing.
Each was used.

Further, in some experiments, rolling was performed while cleaning the surface of the roll on the aluminum rolling side on the rolling exit side using a cloth buff that did not contain an abrasive.

The presence or absence of burn-in and the degree of burn-in in each case are shown in Table 1.

The obtained cladding zone was kept in a furnace in a non-oxidizing atmosphere at a temperature of 350°C for 3 minutes to perform diffusion annealing, and then
By a conventional rolling method using rolling lubricating oil, the plate thickness is 0.
Finish rolling was performed so that the length was 25 m+.

After this product was kept in an atmospheric furnace at 530° C. for 6 minutes, it was examined using a magnifying glass to see if fine scratches had formed in the aluminum part. The results are also listed in Table 1.

As is clear from Table 1, hard chrome-plated rolls are more likely to seize than simple steel rolls, and sulfur-nitrided rolls are more likely to seize than hard chrome-plated rolls even at high rolling reductions. Rolling and crimping can be performed without causing any damage. Cleaning the roll surface with a puff is effective in preventing seizure, and enables rolling at a higher reduction rate.

It is also confirmed that sufficient crimping without causing blisters can be obtained if the rolling reduction ratio is 6% or more.

Table 1 Example 2 Kovar alloy (291%Ni-16%CO-
A strip of 0.6 tm thick and 25 m wide of residual Fe (residual Fe) was used as the cladding material, and an aluminum alloy (JIS 2014
A strip of 15μ thick and 4.6m wide was combined with the equivalent product.

While polishing the widthwise center of the base metal with a wire brush,
An aluminum alloy strip was superimposed on that surface and rolled and crimped at a rolling reduction of 10 to 30 inches without using rolling lubricating oil. The rolling rolls are 30 rolls in diameter, and one set is made of high-speed steel (JIS 5KH51
An abrasive film made by a comparable product was used, and another set was made of cemented carbide.

This clad zone was prepared at a temperature of 350° C. in the same manner as in Example 1.
After annealing for 3 minutes, the plate was finish rolled in a conventional manner using rolling lubricating oil to a plate thickness of 0.25 mm.

This product was also subjected to a heating test in which it was held in an atmospheric furnace at 530°C for 6 minutes to determine whether blisters occurred on the surface of the aluminum alloy strip.

The above results, together with the rolling conditions shown in Table 2, confirm that by using the cemented carbide rolls, it is possible to prevent seizure and achieve rolling crimping at a high rolling reduction.

[Brief explanation of the drawing]

The drawings are explanatory diagrams of the method for manufacturing the cladding band of the present invention. 1...Base material band 2...Aluminum strip 3...Clad band 5A, 5B...Roll roll patent applicant Daido Steel Co., Ltd.

Claims (4)

[Claims] (1) A method of manufacturing aluminum stripes (clad strips) by rolling and pressing aluminum or aluminum alloy strips onto a base material in a stripe shape by cold or warm rolling, in which the surface is coated with hard chromium or sulfur-nitrided. It is characterized by performing rolling crimping at a reduction rate of 6 to 40% without using a rolling lubricant, using steel rolls that have been subjected to seizure reduction treatment or cemented carbide rolls that have low seizure properties. how to. (2) The method according to claim 1, which includes cleaning the surface of the roll while rolling to immediately remove aluminum or aluminum alloy debris that may adhere to the surface. (3) The method according to claim 1, wherein the rolling crimping is followed by diffusion part annealing and finish rolling. (4) Claim 1 in which the base material is a glass sealing alloy
Section method.