JPH0569160A - Production of composite metallic plate - Google Patents

Abstract

PURPOSE:To obtain copper clad steel plate excellent in workability by pressing and heating each material to the optimum temperature through electrice heating. CONSTITUTION:A copper blank 1 is provided with two electric rolls 11, 14 and a copper blank 2 is provided with one electric roll 12, electric powers 21, 23 are connected between the respective electric rolls to flow current, the copper plate is heated at 200-70 deg.C, the steel plate us at 600-910 deg.C and they are sent between the pressing rolls and adhered by pressing at a draft <=0%. In this way, a copper clad steel plate suitable to workability and other different uses can be manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a comparatively thin composite metal plate made of a copper alloy plate such as copper or brass used for materials of electric devices, ornaments, daily necessities, etc., and a plain steel plate such as a low carbon steel plate, That is, the present invention relates to a method for manufacturing a clad plate.

[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.

There is also a method generally called a hot rolling method in which raw materials are superposed at the 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. .. Both of the above methods are premised on the subsequent steps such as rolling and annealing, and it is difficult to apply them to the compounding of materials such as copper and iron that have greatly different annealing temperatures.

Further, as a method applicable to a wide range of material combinations, an explosive deposition method utilizing high pressure generated when explosive explodes is known, but a thick plate can be directly used as a final product. However, it is necessary to consider rolling the thin plate later, and the same problems as those of the above-described cast-rolling method occur.

A method called lap rolling 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. 1 for sufficient bonding
The condition is that the reduction in the pass is made as large as possible. In the case of joining nonferrous metals to each other, it is often performed cold, but the steel sheet is often heated and warmed.

[0006]

In the above-mentioned lap rolling method, as its name implies, the driving force for joining is rolling, and heat only plays an auxiliary role when heating. That is, in the case of a steel plate or the like, since the deformation resistance is large and the rolling force is significantly large in the cold state, it is intended to facilitate heating by softening by heating to some extent.

Therefore, the joined materials have a structure in which the crystal grains are elongated and hardened even after heating, which is the case after cold rolling. For processing applications such as drawing, annealing must be performed for softening. I won't. However, the temperature suitable for annealing is significantly different between copper or copper alloy and steel,
In the case of such 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.

[0008]

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and manufactures a composite metal sheet by stacking at least one copper or copper alloy sheet and at least one ordinary steel sheet and joining them. In the method, the copper or copper alloy plate is heated to 200 to 700 ° C., and the temperature of the ordinary steel plate is set to 600.
To 910 ° C. in an atmosphere having an oxygen concentration of 3% or less while being fed between pressure-bonding rolls and pressure-bonding at a reduction rate of 30% or less.

Further, as heating means, one or more current-carrying rolls are provided on the copper or copper alloy plate and the steel plate to be crimped, respectively, and a current is passed between the current-carrying rolls to perform heating. To do.

[0010]

In the present invention, the metal plates, which are the raw materials of the composite metal plate, are heated and superposed, and are fed between the pressure bonding rolls to be bonded. The heating temperature at this time is 200 ° C. to 700 ° C. for a copper or copper alloy plate, preferably 350 ° C. or higher even in this range, and 600 to 9 for a plain steel plate.
It is heated to 10 ° C, preferably 750 ° C or higher even in this range. In the present invention, the main driving force for bonding is to increase the diffusion rate of atoms due to high temperature, and the heating temperature is higher than the conventional so-called lap rolling method. If the temperature is lower than the above, the bonding strength becomes insufficient, and if the temperature is higher than the above, the crystal grains become coarse, or in the steel sheet, the texture changes due to the microstructural transformation, which is not preferable in terms of material quality. Will also be difficult.

Further, in order to heat at such a high temperature, an oxidation preventing means is necessary, and the steps from heating to pressure bonding are performed in an atmosphere having an oxygen concentration of 3% or less, for example, a nitrogen gas atmosphere. For this reason, it is necessary to provide means such as putting the entire apparatus in a chamber with a protective atmosphere. That is, in the conventional method of low temperature, the oxidation itself is small, and the prevention of oxidation is not so important because a new surface is formed on the joint surface by a high reduction rate to promote the joining, but in the method of the present invention, it will be described later. As the reduction is small, it is important to prevent oxidation. It is desirable that the oxygen content in the atmosphere is as low as possible, but the practical limit is 3%, and if it exceeds this limit, the oxidation of the plate becomes remarkable.

On the other hand, the reduction by the pressure roll is lower than that of the conventional lap rolling method, and the reduction rate, that is, the ratio of the difference between the total sheet thickness and the product sheet thickness is 30% or less, preferably 20% or less. Within the range. The reason why the rolling reduction is 30% or less is that when the rolling reduction increases, the rolling structure during the compression bonding often remains and the quality of the material deteriorates. In the method of the present invention, 20% or less is preferable in order to stop the rolling within the range in which the rolling structure does not remain. If the heating temperature of the material is sufficiently high, it is possible to normally perform pressure bonding if the reduction rate is 5% or more.

The steps of the present invention as described above have a particularly favorable influence on the material. That is, while the conventional lap rolling method has a high reduction rate in crimping, even if heated, since it is below the recrystallization temperature, the crystal grains are in a stretched form and are in a work-hardened state. Therefore, in order to use it for general processing such as bending and squeezing, it must be annealed to be softened, but copper or a copper alloy and steel have different appropriate annealing temperatures. For this reason, if the temperature is made sufficient to soften the steel, the temperature of copper is too high, and problems such as deterioration of material due to coarsening of crystal grains occur. However, according to the method of the present invention, there is no such a problem because the material can be heated to the optimum temperature for each of the plates and the final product can be bonded and bonded.

As the apparatus for carrying out the method of the present invention, various kinds of heating means can be considered, but the method by electric heating previously developed by the present inventors is particularly suitable (Japanese Patent Laid-Open No. 307687/1990). issue). In this, one or more current-carrying rolls are provided on each of a plurality of metal plates, and a composite metal plate is manufactured by continuously feeding current between the current-carrying rolls so that the metal plates overlap each other so that the metal plates overlap each other. Is the way. 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. In this heating method, the temperature of the metal plate of the material is constantly raised, so the heating temperature in the present invention is the temperature immediately before the pressure bonding roll.

Since this heating method requires only a commercial frequency power source, the cost of electric equipment is significantly lower than that of high frequency heating, temperature control is easy, and the temperature distribution in the plate width direction is good. It is suitable to be applied to the above method.

FIG. 2 shows a case where a composite metal plate is manufactured by stacking three plates, with the center being a steel plate, the front and the back are copper plates.
The copper plate 1 and the steel plate 2 are heated by the power source 21 between the energizing rolls 11 and 12, and the copper plate 3 and the steel plate 2 are energized and heated by the power source 22 between the energizing rolls 13 and 12. In this case, the power source 2 is arranged so that the sum of the currents of the two power sources 21 and 22 flows in the steel plate 2.
Phases 1 and 22 are determined. Further, auxiliary heating energizing rolls 14 and 15 are provided for auxiliary heating of the copper plates 1 and 3, and currents are supplied by the power sources 23 and 24.

[0018]

【Example】

(Example 1) Using the apparatus shown in FIG. 1, a two-layer composite metal plate was manufactured from a copper plate having a thickness of 0.3 mm and a width of 300 mm and a low carbon steel plate having a thickness of 0.6 mm and a width of 300 mm (corresponding to JIS standard SPCE). .. That is, in FIG. 1, the metal plate 1 as a raw material was manufactured as a copper plate and 2 as a low carbon steel plate. The heating temperature of the copper plate was 400 ° C., the heating temperature of the steel plate was 800 ° C., and the heating and pressing were performed in a nitrogen atmosphere having an oxygen concentration of 0.1% or less. The rolling reduction with the pressure bonding roll is 10%. The characteristics of the product were examined, but no peeling occurred even after 90-degree bending and bending back test. Although cold rolling was performed, peeling did not occur in this case as well. Other tests such as a peel strength test, an Erichsen test for examining workability, and a deep drawing (Swift cup) test were performed, and as shown in Table 1, good properties were shown. In addition, the Erichsen test and the deep drawing test were carried out including the following examples so that the side of the copper plate was the outer surface that was drawn.

[0019]

[Table 1]

(Embodiment 2) With the apparatus shown in FIG. 2, a copper plate having a thickness of 0.3 mm and a width of 300 mm was used as the front and back metal plates 1 and 3, and a low carbon steel plate having a thickness of 0.6 mm and a width of 300 mm. A three-layer composite metal plate was manufactured with the plate 2 at the center.
Conditions such as heating temperature and rolling reduction were the same as in Example 1, and as shown in Table 1, the product characteristics were good.

(Comparative Example 1) Using a metal plate of the same material as that used in Example 1, a manufacturing process of a two-layer composite metal plate of a copper plate and a low carbon steel plate was carried out. The apparatus is similar to that of the first embodiment shown in FIG.
The heating temperature of the copper plate was 180 ° C., the heating temperature of the steel plate was 550 ° C., and the rolling reduction was 10% as in Example 1 (Table 1). The atmosphere during heating is the same nitrogen atmosphere as in Example 1. The result was that good bonding was not obtained, and the film was immediately peeled off by bending.

(Comparative Example 2) The conditions such as material and heating temperature are the same as those in Comparative Example 1, but the rolling reduction is 35%. As for the product characteristics, as shown in Table 1, although they were joined, the peel strength was low, and the material hardened due to being processed at a temperature lower than the recrystallization temperature, and the workability was poor.

Comparative Example 3 The product produced in Comparative Example 2 was further annealed at 750 ° C. for 30 minutes in a nitrogen atmosphere. As shown in Table 1, the peel strength was increased, the joining was improved, and the workability was also improved, but the annealing temperature was too high for the copper plate, so the crystal grains became coarse and the surface became uneven in the Erichsen test. Orange peel was seen. Also, the limit drawing ratio (LDR), which represents the deep drawability, is not very good. It is considered that this is because the recrystallization texture of the steel sheet is not the optimum one for obtaining the drawability in relation to the rolling reduction.

[0024]

According to the method of the present invention, when manufacturing a composite metal plate of copper or copper alloy and a steel plate of ordinary steel, each metal plate of the raw material is sufficiently heated and then pressure-bonded with a small reduction rate. Therefore, it is possible to form a composite without impairing the original characteristics of each material. Therefore, a composite metal plate suitable for various applications such as deep drawing can be manufactured.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an example of an apparatus for carrying out the method of the present invention.

FIG. 2 is a conceptual diagram showing an example of an apparatus for carrying out the method of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location // B23K 103: 22 (72) Inventor Tadashi Ishimoto 1 Fujimachi, Hirohata-ku, Himeji-shi, Hyogo New Hirohata Works, Nippon Steel Corporation

Claims (2)

[Claims] 1. A method for producing a composite metal sheet by laminating at least one copper or copper alloy sheet and at least one ordinary steel sheet together to produce a composite metal sheet.
It is characterized in that the temperature of the ordinary steel sheet is heated from 00 to 700 ° C. to 600 to 910 ° C. in an atmosphere with an oxygen concentration of 3% or less, and is fed between pressure-bonding rolls and pressure-bonded at a reduction rate of 30% or less. Method for manufacturing composite metal plate. 2. A copper or copper alloy plate and a plain steel plate to be crimped are provided with one or more current-carrying rolls, and a current is passed between the current-carrying rolls to perform heating. 1. The method for manufacturing the composite metal plate according to 1.