JPH05177363A - Production of copper clad steel products - Google Patents

Abstract

PURPOSE:To produce the copper clad steel having excellent joining and adhering properties by superposing copper (alloy) having oxygen content of a specific condition and steel which is a base metal on each other, welding the four circumference thereof in a high vacuum of form a clad assembly, then subjecting the assembly to hot joining and rolling. CONSTITUTION:A cladding material consisting of the copper (alloy) having <=0.06wt.% oxygen content and the base material consisting of steel are superposed on each other. A spacer, release material and dummy are superposed thereon and the four circumferences thereof are welded to form the clad assembly. The four circumferences thereof are welded in the high vacuum and, therefore, oxide films are not formed on the copper. Such clad assembly is subjected to hot joining and rolling to form the copper clad steel. The boundary joint strength of the copper clad steel is not enough is the oxygen content of the copper cladding material exceeds 0.06%. The copper clad steel products having the excellent joining and adhering properties and the shearing strength of the joint boundaries are mass produced at a low cost.

Description

Detailed Description of the Invention

In recent years, in order to utilize high thermal conductivity and excellent corrosion resistance of copper (hereinafter referred to as copper or copper alloy as a general term), for example, reaction plates, pots, pots or kettles for linear motors are used. A copper clad steel material in which copper is used as a composite material for an outer bottom plate of a hull has come to be used, and the present invention relates to a method for producing the copper clad steel material.

[0002]

2. Description of the Related Art Conventionally, the following method has been known as a method for producing a clad material in which dissimilar metals are joined together. a) A method of melting the laminated material and welding it to the base material surface, b) A method of wrapping the laminated material with the base material to form a clad material when the laminated material cannot be melted, c) Explosive pressure bonding or explosive pressure bonding Then, a method of rolling (explosion bonding method), d) A method of rolling and crimping a clad assembly in which a laminated material and a base material are superposed cold or hot (assembly rolling method).

Of these, the explosion-bonding method and the rolling press-bonding method are usually adopted in terms of productivity and product performance.
The explosive deposition method has an economical problem that the manufacturing cost is very high, and therefore, the tendency to adopt the assembling and rolling method is increasing.

However, when the assembling and rolling method is applied to the production of the copper clad steel material, hot pressure-bonding rolling is necessary. At this time, the following problems were pointed out. That is, when copper is heated in the air, CuO oxide is generated on the surface, but the oxide film is formed on the surface of the copper laminated material by heating the clad assembly prior to hot pressure rolling of the copper clad steel material. This is a problem that impedes diffusion bonding of copper and steel during rolling. Therefore, the adhesiveness of the obtained copper-clad steel material tends to be insufficient.

However, in order to avoid the above-mentioned inconvenience, as shown in FIG. 2, the copper base material and the steel base material are overlapped with each other so as to be wrapped with the steel base material and the steel dame or spacer, and then four turns are made. By making a clad assembly by hermetically welding, the air remaining on the internal joint surface is sucked from the pipe inserted inside the clad assembly to vacuum before heating before hot pressing and rolling. Attempts have also been made to prevent oxidation of the surface of the copper-clad material (see, for example, JP-A-63-132787).

However, even in the case of this method, the base material is heated during the four-round welding when the clad assembly is produced, and this heat is transmitted to the inside by heat conduction to raise the temperature of the copper laminated material. Therefore, it is difficult to avoid the formation of an oxide film due to the reaction between the air remaining on the internal joint surface and the copper laminated material surface. Therefore, it is needless to say that even if the inner joint surfaces of the clad assembly in this state were evacuated and pressure-bonded and rolled, the copper clad steel material excellent in performance such as joint adhesion and shear strength could not be stably manufactured. .

Therefore, in practice, in order to prevent oxidation of the copper-bonding-material joining surface, nickel-plating is performed on the copper-bonding-material joining surface before assembling the clad assembly. However, nickel plating is relatively expensive, which is an advantage of the assembling and rolling process in "economy".
It was the current situation that we could not fully enjoy.

In view of the above, the object of the present invention is to obtain a stable copper-clad steel material in a good joined state at low cost by the assembly rolling method without requiring an insert material such as nickel plating. It was to establish a manufacturable means.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, namely, "A composite material made of copper having an oxygen content of 0.06% by weight or less and a base material made of steel are superposed. After that, the four edges are welded in a high vacuum to form a clad assembly, which is then hot-bonded and rolled to obtain a copper-clad steel material with excellent interfacial bond strength in the as-rolled and heat-treated state. It has a major feature in that it enables mass production at low cost.

[0010]

In other words, according to the present invention, for example, the entire welding chamber is made to have a high vacuum so that the joint surface of the copper-clad material is prevented from being oxidized by the conduction of welding heat when the clad assembly is produced. This method employs welding, and if sealed welding is performed under such a high vacuum state, the copper base material surface becomes hot due to heat conduction from the steel base material heated by the welding heat. Even if the temperature is raised, there is no air (oxygen) in contact with this, so that no oxide film is formed.
Therefore, since the joint surface between the steel base material and the copper laminated material is hermetically sealed while being kept clean by the four-round welding of the above-mentioned clad assembly, even if nickel plating is not applied to the copper laminated material surface, the subsequent heat treatment is not performed. The material is firmly joined by the intercompression rolling, and a copper clad steel material having excellent joint adhesion and shear strength can be obtained at low cost.

Here, the oxygen content of the copper alloy is limited to 0.06% by weight or less, because the copper-clad steel material produced when the oxygen content of the copper alloy exceeds 0.06% by weight. This is because the interfacial bonding strength of is not sufficient and does not show high shear strength.

The "high vacuum" in which the clad assembly is welded on all four circumferences means a high vacuum region having a vacuum degree of 10 ^-4 Torr or more, and at low vacuum (vacuum degree of ^{-10 -2} Torr), it is in the atmosphere (air). ) Is not completely exhausted, an oxide film is formed on the surface of the copper laminated material, and electron beams and laser beams are generated at medium vacuum (vacuum degree: 10 ^-2 to 10 ^-3 Torr). Etc. do not occur stably, so welding work becomes difficult. Further, the hot joining rolling at this time may be performed in a temperature range of about 850 to 1000 ° C.

Next, the present invention will be described more specifically by way of examples.

Example First, the following clad assembly material was prepared. A) Laminated material (O content: 0.006wt% copper) ... 20mm thickness x
1500mm width x 3400mm length, B) Base material (C content: 0.11wt% carbon steel) ... 76.5mm thickness x
1600mm width x 3500mm length, C) Dummy material (C content: 0.08wt% carbon steel) ... 55mm
Thickness x 1600mm width x 3500mm length, D) Spacer (C content: 0.10wt% carbon steel) ... 26m
m thickness x 50 mm width x length for four turns, E) Release material [Ti foil and high carbon (C content: 0.25 ■ 0.
65 wt%) iron foil].

Then, after assembling this as shown in FIG. 1, the four circumferences thereof are hermetically sealed and welded in accordance with "conventional method", "method disclosed in Japanese Patent Laid-Open No. 63-132787" and "method of the present invention". Clad assembly (175.5mm thick x 1600mm x 35
00mm length) was created. Incidentally, in the conventional method, the joint surface of the laminated material was nickel-plated before the material was assembled. Next, after heating this clad assembly, it is hot-joined and rolled to measure 21 mm (Cu: 5 mm + 16 mm) x 2000 mm.
A copper clad steel plate of × 10500 mm was obtained. Table 1 shows the evaluation results of each of the copper clad steel plates obtained in this way, together with their manufacturing conditions.

[0015]

[Table 1]

As is clear from the results shown in Table 1, according to the method of the present invention, it is possible to manufacture a copper clad steel sheet having a good joining condition at a low cost.

[0017]

[Summary of Effects] As described above, according to the present invention, it becomes possible to mass-produce a copper clad steel material having excellent bonding adhesion and shear strength at the bonding interface at low cost, which is industrially useful. The effect is brought.

[Brief description of drawings]

FIG. 1 is a conceptual diagram illustrating an assembling state of a clad material in an example.

FIG. 2 is an explanatory diagram of a conventional method (method disclosed in Japanese Patent Laid-Open No. 63-132787).

Claims (1)

[Claims] 1. A clad assembly is obtained by superposing a laminated material made of copper or a copper alloy having an oxygen content of 0.06% by weight or less and a base material made of steel, and welding the four circumferences thereof in a high vacuum. Then, a hot joining rolling is applied to this, and a method for producing a copper clad steel material having good interfacial joining strength.