JP2812898B2 - Method for manufacturing clad plate with excellent formability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a clad plate of an aluminum or aluminum alloy plate and a stainless steel plate having a low ear ratio and excellent formability, and more particularly to a press-formed article. And in the clad plate of aluminum or aluminum alloy plate and stainless steel plate used as a material for its applied products, the deep draw forming process when forming into objects, etc., is excellent in formability and deep drawing The ear ratio after processing is -2.
The present invention relates to a method for manufacturing a clad plate having a very small variation of 0 to + 2.0% and excellent moldability.

[0002]

2. Description of the Related Art Conventionally, objects have been commercialized by deep drawing of aluminum alloy plates or stainless steel plates. Aluminum alloy utensils have good thermal conductivity, but have drawbacks such as low strength and easy deformation and poor appearance.Stainless steel utensils have good appearance and strength, but heat conductivity There are drawbacks such as poor properties and easy burning. Therefore, by using a clad plate of an aluminum alloy plate and a stainless steel plate and processing the container into an aluminum alloy on the inside and stainless steel on the outside, the container has excellent thermal conductivity, heat retention, strength and appearance. Could be obtained. Conventionally, in the production of clad plate material of this aluminum alloy plate and stainless steel plate, an aluminum alloy plate obtained by performing general melting → casting → soaking treatment → hot rolling → cold rolling if necessary Was.

[0003]

However, as described above, a clad plate manufactured by cold rolling a stainless steel plate and an aluminum alloy plate manufactured to a predetermined thickness without annealing treatment or the like. However, there is a disadvantage that the difference in strength and hardness between the aluminum alloy plate and the stainless steel plate is large. In addition, since these plates have differences in elongation and formability, it is difficult to form a clad plate of this aluminum alloy plate and a stainless steel plate, and even if formed, the ear ratio is high. Become.

[0004] Further, after the aluminum alloy plate and the stainless steel plate are clad and then diffusion annealing is performed at a high temperature in order to increase the bonding strength between the aluminum alloy plate and the stainless steel plate, the recrystallized structure becomes coarse.
When the obtained clad plate is formed and processed, there are problems such as rough surface.

The present invention has been made in view of the above problems, and provides a method for producing a clad plate having excellent moldability, an ear ratio close to 0%, small variations and excellent moldability. The purpose is to do.

[0006]

According to the present invention, there is provided a method for producing a clad sheet having excellent formability, comprising the steps of: hot rolling an aluminum or aluminum alloy material; and performing cold rolling at a working ratio of 30% or more. 200 to 300
A step of obtaining an aluminum or aluminum alloy sheet by annealing at a temperature of ℃, and a stainless steel sheet is combined with the aluminum or aluminum alloy sheet, and both are clad by hot or cold rolling, and then 180 to 350 ° C.
And a step of performing diffusion annealing at a temperature of

[0007]

In the following, both aluminum and aluminum alloy are collectively referred to as aluminum material. First, the manufacturing conditions for the aluminum material will be described. The cold working ratio of an aluminum material plate has a great influence on the formability and ear ratio when the aluminum material plate and the stainless steel plate are clad, and then the clad plate is formed. In other words, the aluminum sheet obtained by hot rolling only or cold-rolled at a working ratio of less than 30% after hot rolling has a too low cold-working rate. Ears tend to be large. A clad plate in which such an aluminum plate and a stainless steel plate are clad has a large negative ear. For this reason, when this clad plate is formed into a vessel or the like, defects such as cracks are likely to occur when drawing or ironing. Therefore, the cold working ratio of the aluminum plate used for manufacturing the clad plate is set to 30% or more.

[0008] The annealing treatment of an aluminum sheet plays a large role in the formability and ear rate of a clad sheet as well as the cold working rate of an aluminum sheet. In other words, if the annealing process is not performed, or if the annealing process is performed at a temperature lower than 200 ° C., the aluminum material plate is clad with the stainless steel plate while being processed, so that the stainless steel plate is Unnecessary processing is added, and it becomes difficult to form the obtained clad plate. Further, when annealing is performed at a temperature higher than 300 ° C., aluminum has a recrystallized structure, and the aluminum material plate tends to have a large negative ear. If the aluminum material plate and the stainless steel plate are clad and then subjected to diffusion annealing treatment, the negative ear is likely to be large, resulting in a clad plate having poor formability. Therefore, the annealing temperature after the cold working of the aluminum plate is set to 200 to 300 ° C.

[0009] After the aluminum plate and the stainless steel plate manufactured by the above-described method are clad by hot pressing or cold pressing to a predetermined thickness, the bonding strength of the bonding surface between the aluminum plate and the stainless steel plate is reduced. In order to increase the amount, a diffusion annealing treatment is performed. The diffusion annealing temperature is 18
If the temperature is lower than 0 ° C., no diffusion occurs at the interface between the aluminum material plate and the stainless steel plate, and sufficient bonding strength cannot be obtained. Further, when the diffusion annealing treatment is performed at a temperature exceeding 350 ° C., the aluminum material is recrystallized and crystal grains grow, resulting in coarse crystal grains. For this reason, when forming a clad plate subjected to diffusion annealing treatment at this temperature, a negative ear may be generated on the clad plate, or a rough surface such as orange peel may occur on an aluminum material plate constituting the clad plate. Become. Therefore, the diffusion annealing temperature is set to 180 to 350 ° C.

[0010] The clad material manufactured as described above has excellent ear ratio and moldability.

[0011]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples.

First Embodiment Melting → casting → hot rolling by a conventional method, cold rolling at a cold working rate of 0% (as hot rolled) to 43%, and a composition of JIS A1100 4. Thickness specified in
A 7 mm pure aluminum plate was manufactured. After heating the pure aluminum plate at a temperature of 240 ° C. for 24 hours to perform an annealing treatment, the pure aluminum plate and a stainless steel plate (JIS SUS436) are pressed against each other by cold rolling, and the plate thickness is 2.3 mm. Was manufactured. Thereafter, the clad plate was subjected to a diffusion annealing treatment by heating at a temperature of 200 ° C. for 12 hours.

The characteristics of the clad plate manufactured as described above were examined mainly by measuring ear ratio. The flat-headed punch was set to have a diameter of 40 mm and the blank had a diameter of 72 mm (drawing ratio: 1.80), and the clad plate was drawn by an Erichsen universal hydraulic testing machine.
°, 45 °, 90 °, 135 °, 180 °, 225 °,
Ear heights were measured in eight directions of 270 °, 315 ° and 360 °, and the ear ratio was calculated from these measured values. The surface roughness after molding was visually observed. The results are shown in Table 1 below. Formability at the time of drawing, such as when cracks or breaks occur at the time of drawing, when failure occurs ×,
In the case where the molding was successfully performed, it was indicated by ○.

In Examples 1 and 2, the cold working ratio was 32
%, 43%, and 30% or more, the ears became positive ears, and the ear ratios were as small as +0.9 and +1.7, respectively, indicating that the moldability was good. On the other hand, Comparative Example 1
-3, the cold working rate of the pure aluminum plate is 0
%, 14%, 25% and less than 30%, which are lower than the range specified in the present invention, so that the negative ear is large and the moldability is poor.

[0015]

[Table 1]

Second Example A pure aluminum plate having a thickness of 5.7 mm and a composition defined by JIS A1100 was subjected to melting → casting → hot rolling by a conventional method, cold rolling at a working ratio of 43%. Manufactured.
The pure aluminum plate is heated at a temperature of 150 to 360 ° C for 2 hours.
Annealed by heating for 4 hours or unannealed stainless steel sheet (J
IS SUS436) by cold rolling to produce a clad plate having a thickness of 2.3 mm. Then 200
This clad plate was subjected to a diffusion annealing treatment by heating at a temperature of ° C. for 12 hours.

The characteristics of the clad plate manufactured as described above were examined mainly by measuring ear ratio. The ear ratio was measured in the same manner as in the first example. Also,
The surface roughness after the molding was visually observed. The results are shown in Table 2 below. As in the first embodiment, the formability during drawing is:
When a defect occurred, such as when a crack or a break occurred during drawing, the result was indicated by x, and when the molding was successfully performed, the result was indicated by ○.

In Examples 3 to 5, the annealing temperature of the pure aluminum plate was 200 to 300 ° C., the ear ratio of the clad plate was small, and the moldability was good. On the other hand, in Comparative Example 4, the pure aluminum plate was not annealed,
In Comparative Example 5, the annealing temperature of the pure aluminum plate was 15
Since the temperature was 0 ° C., which was lower than the range specified in the present invention, the molding processability was poor. Further, in Comparative Example 6, since the annealing temperature of the pure aluminum plate was 360 ° C., which was higher than the range specified in the present invention, the minus ears became large and it was found that the skin became rough.

[0019]

[Table 2]

Third Example A pure aluminum plate having a thickness of 5.7 mm, which is subjected to melting → casting → hot rolling by a conventional method, cold rolling at a working ratio of 43%, and having a composition specified by JIS A1100, is used. Manufactured.
The pure aluminum plate was annealed by heating at a temperature of 240 ° C. for 24 hours and a stainless steel plate (JIS SUS436) was pressed by cold rolling to produce a clad plate having a plate thickness of 2.3 mm. . Thereafter, the clad plate was subjected to a diffusion annealing treatment by heating at a temperature of 120 to 360 ° C. for 12 hours. The characteristics of the clad plate subjected to the diffusion annealing treatment and the clad plate not subjected to the diffusion annealing treatment were examined mainly by measuring ear ratio. Measurement of ear rate and observation of rough skin,
It carried out by the method similar to 2nd Example. The results are shown in Table 3 below.

In Examples 6 to 9, since the diffusion annealing treatment was performed in the temperature range of 180 to 350 ° C., the ear ratio of the clad plate was low and the moldability was good. On the other hand, in Comparative Example 7 in which the diffusion annealing was not performed,
Comparative Example 8 performed at a temperature of 20 ° C. and this treatment was performed at 150 ° C.
In Comparative Example 9 which was performed at the temperature of the above, the diffusion annealing treatment was not performed, or the diffusion annealing temperature was lower than the range specified in the present invention. In Comparative Example 10 in which the annealing temperature was 360 ° C., which was higher than the range specified in the present invention, the negative ear was large and the skin became rough.

[0022]

[Table 3]

In this embodiment, the annealing time of the pure aluminum plate is set to 24 hours. However, in order to obtain the effect of the present invention, the annealing time may be 6 hours or more.

Although each of the above-mentioned embodiments uses a pure aluminum plate, the same result can be obtained by using an aluminum alloy plate.

[0025]

As described in detail above, according to the present invention, an aluminum or aluminum alloy plate is subjected to cold rolling at a working ratio of 30% or more to a predetermined thickness.
Since annealing is performed at a temperature of 200 to 300 ° C., then a stainless steel plate is combined with the aluminum or aluminum alloy plate, and both are clad by hot or cold rolling, and then diffusion annealing is performed at a temperature of 180 to 350 ° C. Thus, a clad plate having a small ear ratio and excellent moldability can be obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-309561 (JP, A) JP-A-8-39269 (JP, A) JP-A-7-303977 (JP, A) JP-A-1- 266981 (JP, A) JP-A-3-271358 (JP, A) JP-A-59-185588 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B23K 20/04 B21B 3 / 00

Claims (1)

(57) [Claims] An aluminum or aluminum alloy material is hot-rolled, cold-rolled at a working ratio of 30% or more to a predetermined thickness, and then annealed at a temperature of 200 to 300 ° C. A step of obtaining an aluminum alloy plate, and a step of combining a stainless steel plate with the aluminum or aluminum alloy plate, cladding the both by hot or cold rolling, and then performing a diffusion annealing treatment at a temperature of 180 to 350 ° C. A method for producing a clad sheet having excellent moldability.