JPH0557461A - Manufacture of soft composite metallic plate - Google Patents

Abstract

PURPOSE:To produce the soft composite metallic plate excellent in workability at a low cost by using plural metallic plates being in a state of cold rolling as it is, softening them, and simultaneously, executing pressure welding. CONSTITUTION:On each of plural metallic plates being in a state of cold rolling as they are, one or two or more electric conduction rolls are provided, a current is allowed to flow between the electric conduction rolls, and while heating them to a recrystallization temperature or above of the respective metallic plates, they are fed continuously between pressure welding rolls so that these metallic plates are superposed. Draft of the pressure welding roll is regulated to <=30%.

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 thin composite metal plate used for electric appliances, daily necessities, ornaments, automobiles, etc., that is, a clad material having a good workability. ..

[0002]

2. Description of the Related Art There are various techniques for producing a composite metal sheet. For example, a method of producing a composite from the beginning of the production process is called a casting rolling method, and one material is suspended in a mold. There is a method of making an ingot that is slab-filled. Further, there is also a method generally called a hot rolling method in which raw materials are superposed at a stage of a slab having a thickness of several hundred millimeters and the periphery is welded to prevent oxidation, and then heated and rolled to bond.

All of the above methods are premised on the subsequent steps such as rolling and annealing. However, since the composite metal plate is originally a combination of different materials, the temperature to be annealed is different. However, it is difficult to bring out the original characteristics of the material. Also, as a method that can be applied to a wide range of material combinations, the explosive deposition method that utilizes the high pressure generated when explosives explode is known. Then, it is necessary to consider rolling later, and the same problems as those of the above-described cast rolling method occur.

A method called an lap rolling method is known as a method applied exclusively to a thin plate clad material. This is a method in which sheets of material are stacked cold or warm, sent to a rolling mill, pressed, and pressure-bonded, and are usually continuously formed in a coil shape. This method is based on the premise that a metal plate, which is the material to be the final product, is used as the material for compounding. In this lap rolling method, as the name implies, the driving force for joining is the rolling, and the heat only plays an auxiliary role when heating. That is, in order to perform sufficient bonding, it is a condition that the rolling reduction in one pass is made as large as possible. Therefore, the material is heated to some extent to soften the material to facilitate the rolling reduction.

Therefore, the joined materials have a structure in which the crystal grains are expanded and hardened even after heating, similar to that after cold rolling. For processing applications such as drawing, annealing must be performed for softening. I won't. However, in the case of a composite metal plate made of different materials, it is difficult to perform annealing that satisfies the requirements of both materials. Therefore, the material had to be compromised to some extent.

[0006] Japanese Patent Laid-Open No. 2-307687 is a technique developed mainly for heating means focusing on insufficient heating in the conventional lap rolling method. This is to install one or more energizing rolls on each of a plurality of metal plates,
This is a method for producing a composite metal plate by continuously feeding current between the pressure rolls so that a plurality of metal plates are superposed while passing a current between the current-carrying rolls. That is, as shown in FIG. 1, the metal plate 1 of the material is provided with two energizing rolls 11 and 14, and the metal plate 2 is provided with one energizing roll 12, and power sources 21 and 23 are connected between the respective energizing rolls. The composite metal plate 5 is manufactured by sending the current between the pressure-bonding rolls 4 so that the metal plates of the raw materials overlap each other while passing an electric current.

As the power source, either a low frequency AC power source or a DC power source can be used. The current of the power source 21 is one of the energizing rolls 1.
From 1 to the metal plate 1 of one material, through the portion of the pressure bonding roll 4, to the metal plate 2 of the other material to the other energizing roll 12. That is, the current values of the metal plates 1 and 2 of each material are the same. For example, the material metal plate 1 is a copper plate, 2
Is a steel plate, the steel plate has a higher electric resistance unless the copper plate is extremely thinner than the steel plate. Therefore, at the same current value, the steel sheet is heated more strongly. The heating temperature required for joining is lower in the copper plate, but since the heating is still insufficient in many cases, the energizing roll 14 for auxiliary heating is provided, and the current is supplied from the power source 23 to assist the heating.

[0008]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Since the technology of No. 7687 requires only a commercial frequency power source, the cost of electric equipment is significantly lower than that of high frequency heating and temperature control is easy. Further, since the temperature distribution in the plate width direction is uniform, it can be heated to a desired and sufficient temperature.

[0009] On the other hand, however, since such a method is compounded one step before the product of the composite metal plate, the cost for compounding is added to the cost of each material as the product of the metal plate. .. Therefore, it is necessary to develop a method for manufacturing a composite metal plate at the lowest possible cost while improving the material properties.

[0010]

Means for Solving the Problems The present invention is to solve the above problems, and in a method for producing a soft composite metal sheet by stacking a plurality of metal sheets, the metal sheet is cold-rolled as it is. A metal plate is used, and one or more current-carrying rolls are provided on each of the metal plates, and an electric current is applied between the current-carrying rolls so that the metal plates overlap each other while being heated to a temperature equal to or higher than the recrystallization temperature of each metal plate. It is characterized in that it is continuously fed between the pressure rolls. In addition, it is also characterized in that the reduction rate by the pressure bonding roll is 30% or less.

[0011]

In the present invention, the cold-rolled metal plate is used as the material metal plate. In the conventional lap rolling method, the point is to make the reduction in one pass as large as possible in order to achieve good pressure bonding, and it has been taken for granted that a material softened as much as possible by annealing is used as the material. However, in the present invention, a material that is not annealed after cold rolling is used.

This is because the heating method applied in the present invention, which will be described later, can also serve as an annealing step, whereby the cost can be reduced by omitting the annealing step. In manufacturing a composite metal plate using a material having a thickness close to that of the final product, the material thickness is inevitably thin, but such a thin metal plate, for example, an annealing of 0.4 mm or less is a special device. What is needed is high annealing cost. In the present invention, by using the material as cold-rolled, the cost can be reduced and the selection range of the material thickness can be expanded to the thinner one.

The term "cold-rolled metal plate" as used in the present invention means an intermediate product as a raw material premised on annealing. For example, in the case of thin steel sheets, temper rolling (skin pass) with a rolling reduction of several% may be performed after annealing in order to prevent stretcher strain that occurs during drawing, and such cold rolling is referred to in the present invention. It is not a metal plate as it is. In addition, materials such as copper and aluminum may be finally subjected to a slight reduction to adjust the hardness, but this is not applicable because these are not originally intermediate products.

The above-mentioned cold-rolled metal plates are stacked and fed between pressure-bonding rolls to form a composite metal plate, which is heated by energizing the metal plate. This is performed by using the apparatus described above with reference to FIG. 1 and providing one or more current-carrying rolls on each metal plate and applying a current between the current-carrying rolls. In the conventional lap rolling method, the driving force for pressure bonding is rolling and the heating is auxiliary, but in the present invention, diffusion at the bonding interface at high temperature is the main driving force.

For this reason, the heating conditions must satisfy both the conditions suitable for joining for compounding the materials and the conditions suitable for exhibiting the material properties by annealing. In the heating method by energization between the energizing rolls, the temperature rise continues until the metal plate enters the pressure-bonding roll. Generally, the temperature of recrystallization annealing of a metal material is determined on the assumption that it is maintained at a certain temperature for a certain period of time. This time is several tens of seconds to several minutes in the case of continuous annealing and several hours in the case of batch annealing, but in any case, it is premised on a certain holding time. However, the electric heating used in the method of the present invention is rapid heating as described above, and it is impossible to maintain a constant temperature. Therefore, in the present invention, with respect to the target annealing temperature in a general continuous annealing furnace,
To obtain the same annealing result, a slightly higher temperature such as several tens of degrees is required.

On the other hand, if the heating is carried out at a temperature suitable for the above-mentioned recrystallization annealing, it will usually be a temperature suitable for bonding by pressure bonding.
Good reduction with a small reduction rate. When the metal plate is caught between the pressure-bonding rolls, heating is not performed during this period, so that the temperature suddenly drops due to contact with the rolls. Therefore, when the reduction is large, the material often hardens without recrystallization. Therefore, when manufacturing a soft composite metal plate suitable for the intended processing use of the present invention, it is desirable that the rolling reduction be 30% or less. When the metal plate made of the above-mentioned material is sufficiently heated, sufficient compression bonding is performed if the reduction ratio is 5% or more.

Further, in the method for producing a composite metal plate of the present invention, since the heating temperature of the metal plate is higher than the recrystallization temperature, it is necessary to take measures to prevent oxidation for many metals. For example, in the case of steel, the amount of oxygen is 3% to prevent oxidation in a nitrogen atmosphere.
Below.

[0018]

EXAMPLE A two-layer composite metal plate was manufactured using the apparatus shown in FIG. All the metal plates used are cold rolled, 0.004% carbon steel, JIS standard SUS
304 stainless steel, aluminum, and copper were used, and they were used in combination. The heating temperature above the recrystallization temperature is 850 ° C. for carbon steel, 1100 ° C. for stainless steel, 350 ° C. for aluminum, and 600 ° C. for copper. A board was manufactured. It can be seen that all of them are joined well in the 180-degree bending test without peeling, have a low hardness and a good Erichsen value, and are sufficiently softened.

[0019]

[Table 1]

[Table 2] On the other hand, a comparative example is shown in Table 2. Although Comparative Example 1 uses an annealed material as a raw material, the product characteristics are the same as those of the Examples, and it can be seen that it is rational to use a cold rolled material in the present invention. Further, in Comparative Example 2, since the heating temperature of the carbon steel is 650 ° C., which is lower than the recrystallization temperature, the products are joined but the hardness of the product is high and the workability is poor.

Example 5 is an example of producing a three-layer composite metal plate using the apparatus shown in FIG. The steel plate 2 and the aluminum plate 1 are heated by the power source 21 between the energizing rolls 11 and 12,
The steel plate 3 and the aluminum plate 1 are energized by the power source 22 between the energizing rolls 13 and 12 to be heated. In this case, the phases of the power supplies 21 and 22 are determined so that the sum of the currents of the two power supplies 21 and 22 flows through the aluminum plate 1. Further, in order to supplementarily heat the aluminum plate 1, a current is also made to flow between the energizing rolls 16 and 12 by the power supply 25.

As shown in Example 5 in Table 1, there was no peeling due to the bending test, the hardness was low, and the workability was good. On the other hand, Comparative Example 3 is a composite metal plate prepared by using the annealed material of the metal plate of each corresponding material, and has the same characteristics as those of the Example 5. Therefore, it can be seen that there is no difference in quality even if the material as cold-rolled is used.

[0022]

EFFECTS OF THE INVENTION According to the present invention, since joining is performed while heating under the annealing conditions suitable for the metal plates of the respective materials, a soft composite metal plate having good workability can be obtained without impairing the characteristics of the metal plates of the respective materials. Can be made. Under such heating conditions, the amount of reduction for crimping is small, so workability is not impaired, and since the material as cold-rolled is used, the cost is reduced, and it is difficult to anneal as a material, and thin materials can be used. It can be used as it is rolled, and the applicable range is widened.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an apparatus used in a manufacturing method of the present invention.

FIG. 2 is a diagram showing an example of an apparatus used in the manufacturing method of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Teruki Hayashida 1 Fuji-machi, Hirohata-ku, Himeji-shi, Hyogo Nippon Steel Corporation Hirohata Works (72) Inventor Takao Nagase 1 Fuji-cho, Hirohata-ku, Himeji-shi, Hyogo Address Nippon Steel Works Hirohata Works

Claims (2)

[Claims] 1. A method of manufacturing a soft composite metal sheet by stacking a plurality of metal sheets, wherein a metal sheet that has been cold-rolled is used as the metal sheet, and one or more energizing rolls are provided for each of the metal sheets. , A current is passed between the energizing rolls, while being heated to the recrystallization temperature of each metal plate or higher, continuously fed between the pressure rolls so that these metal plates overlap with each other. Manufacturing method. 2. The method for producing a soft composite metal plate according to claim 1, wherein the reduction rate by the pressure roll is 30% or less.