JPH0112592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a flat conductive rod coated with corrosion-resistant coating.

Regarding the manufacturing method of the corrosion-resistant coated flat conductive rod, a conductive material tube such as Cu having a smaller diameter is inserted into a corrosion-resistant material tube such as stainless steel or Ti, and after being formed into an oval shape by press working, it is rolled. This is then tightened using bolts and nuts that have a smaller coefficient of thermal expansion than the component, and is heat treated.
A manufacturing method has been proposed in which the above-mentioned product of predetermined dimensions is obtained by applying pressure to both materials to join them together.
Although this method is an excellent method for reducing the pressing force during molding, (1) the use of pipes made of both corrosion-resistant and conductive materials increases material costs;

(2) Since the main reason for reducing the pressing force is the use of a tube as the conductive material, it is not possible to increase the cross-sectional area of the conductive material, which is the lifeblood of the conductive rod. If an attempt is made to increase the size, the diameter of the conductive material tube must be increased, and as a result, the resulting conductive rod has an abnormally flat shape that is extremely wide relative to its thickness, making it impractical. Furthermore, the diameter of the expensive corrosion-resistant material tube must also be increased, resulting in a significant increase in material costs.

(3) Corrosion-resistant materials and conductive materials are fastened together using bolts and nuts with a small coefficient of thermal expansion, and heated to form a diffusion bond. However, with the method of generating pressure by the difference in thermal expansion, there is naturally a limit to the pressure that can be generated, and it is not possible to Connection cannot be expected. In particular, bolts and nuts soften and deform themselves at high temperatures, making it difficult to ensure sufficient pressing force.

It also has the following disadvantages.

The present invention was proposed in order to eliminate the drawbacks of the above-mentioned conventional methods, and when manufacturing a conductive rod in which a conductive material having a flat cross section is coated with a corrosion-resistant material, a solid rod of a conductive material is inserted into a pipe of a corrosion-resistant material. After this is pressed at room temperature to perform the first mild flattening press forming, it is heated in a vacuum to a temperature higher than the lower recrystallization temperature of the two materials, and at that temperature. Hot forming and diffusion welding are performed at the same time by applying a pressure of σ _0.2 or more to the conductive material. Then, after cooling to room temperature, a second mild flattening finish press forming is performed in which the flat surface is pressed again, and the specified shape is formed. A method for manufacturing a conductive rod is provided, which is characterized by obtaining a conductive rod having a certain shape and dimensions.

Therefore, in the method of the present invention, since a solid rod is used as the conductive material, there is an advantage that the material cost is low and the cross-sectional area of the conductive material can be arbitrarily and economically secured. Further, in the method of the present invention, the cold press forming is divided into two steps and hot diffusion welding is performed between the two steps, so there is an advantage that the conductive material and the corrosion-resistant material can be firmly joined with an appropriate pressure.

The method for manufacturing a conductive rod of the present invention will be described with reference to embodiments shown in the drawings.

First, FIG. 1 shows the basic steps of the manufacturing method of the present invention. In the figure, 1 is a pipe made of a corrosion-resistant material such as stainless steel or Ti, 2 is a solid rod made of a conductive material such as Cu, and 10 is a diffusion welded portion.

In the manufacturing process, first, as shown in FIG. 1, a solid rod 2 of a conductive material is inserted into a corrosion-resistant material tube 1. Next, a first light press molding is performed at room temperature to obtain the shape No. 2. Subsequently, this is subjected to hot forming and diffusion welding at the same time to obtain shape 3. Thereafter, the temperature is lowered to room temperature, and a second light finishing press molding is performed to obtain a predetermined conductive rod as shown in 4.

Figures 2 to 5 show the above steps in detail, and 3 is a pressure jig made of heat-resistant high-strength steel;
5 is a pressure receiving jig made of the same material, 5 is a pressure body for diffusion welding, 6 is a pressure holder, 7 is a heater for diffusion welding, 8 is a diffusion welding chamber wall, and 9 is an exhaust pump.

Fig. 2 1 shows how each part is set during the first light press forming, and Fig. 2 2 shows the situation after the forming.
After inserting the assembly into the pressure receiving jig 4, a press forming force of P is applied via the pressure jig 3 to form the product. Adjust the protrusion height. Since the length between the protrusions at both ends of the pressure receiving jig 4 is the same as the length of the assembly, the deformation of the assembly does not occur in the length direction due to press forming, and only the thickness is reduced, in other words, the width is increased. occur uniformly.

Fig. 3 1 shows how each part is set when hot forming and diffusion welding are carried out simultaneously, and Figs. 3 2 and 4 show the situation when these are completed. , of the recrystallization temperature of the conductive material,
Hot forming and diffusion welding are performed simultaneously by heating to a temperature higher than the lower recrystallization temperature and applying a pressure P of σ _0.2 or higher to the conductive material at that temperature. The amount of deformation at that time is adjusted by the protruding height of both ends of the pressure receiving jig.

Fig. 5 1 shows the setting of each part during the second light finishing press forming to finish the assembly after hot forming and diffusion welding to a predetermined thickness, and Fig. 5 2 shows the situation after the forming. The construction is basically the same as that shown in Figure 2.

The effects of the production method of the present invention using such steps are as follows.

(1) Since a solid rod is used as the conductive material, the material cost is low, and the cross-sectional area of the conductive material, which is the biggest problem in use as a conductive rod, can be secured arbitrarily and most economically.

(2) Room-temperature press forming, which requires the most pressure, is
By dividing the process into several batches and minimizing the amount of molding, the process can be performed with a small pressing force, similar to when a pipe is used as the conductive material. In other words, in the first press, it is only necessary to slightly plastically deform the solid rod of the conductive material.
In the second press, the conductive material is softened by the heating cycle of diffusion welding, and this is because the conductive material is finished and formed into a predetermined shape with a slight press force and a slight plastic deformation. In the process of simultaneously performing hot forming and diffusion welding, which performs most of the forming, the conductive material is extremely softened at high temperatures and plastic deformation occurs with a small force, so a small pressing force is sufficient.

(3) As for joining, the required pressure can be applied reliably as desired, and extremely excellent joining strength can be obtained.

A specific example will be explained below.

Specific example 1 SUS304L with wall thickness 3mm, outer diameter 30mm, length 1500mm
A 23mmφ solid copper rod is inserted into the tube, and an assembly with a wall thickness of 27mm is made by press molding at room temperature.
In an atmosphere of 10 ^-3 Torr, this was heated to 950℃ and pressurized for 30 minutes to produce an assembly in which the 17mm thick SUS304L and copper were completely bonded. Next, it is made into Cu with a wall thickness of 16 mm by room temperature press finishing molding.
A conductive rod coated with SUS304L was obtained. The strength of the joint was 20Kg/mm ² (ASTM shear strength).
That is, the above-mentioned flat conductive rod having excellent bonding strength was obtained using a solid rod made of conductive material by a manufacturing method including two cold press molding steps and one hot forming followed by diffusion welding.

Specific example 2 17 in a Ti pipe with a wall thickness of 1 mm, an outer diameter of 20 mm, and a length of 1500 mm.
After inserting a mmφ solid copper rod (10μ Cr plating on copper) and press forming an assembly with a wall thickness of 18mm at room temperature, it was heated to 850℃ in an atmosphere of 5×10 ^-3 Torr.
By raising the temperature to
We fabricated an assembly in which Ti and copper were completely bonded.
Then, it is finished by room temperature press molding to have a wall thickness of 12mm.
A conductive rod made of Cu coated with Ti was obtained. The strength of the joint was 20Kg/mm ² (ASTM shear strength).
That is, the above-mentioned flat conductive rod having excellent bonding strength was obtained using a solid rod made of conductive material by a manufacturing method including two cold press molding steps and one diffusion welding step after hot molding.

[Brief explanation of drawings]

Figures 1 to 5 are schematic diagrams of one embodiment of the method of the present invention, where Figure 1 is an explanatory diagram of the process of the manufacturing method of the present invention, Figure 2 is an explanatory diagram of the first press forming, and Figure 3 is an explanatory diagram of the first press forming. The figure is an explanatory diagram of hot forming, FIG. 4 is a cross-sectional view taken from the side shown in FIG. 3, and FIG. 5 is an explanatory diagram of second finishing press forming. 1: Corrosion-resistant material pipe, 2: Conductive material solid rod, 10:
Diffusion weld.

Claims (1)

[Claims] 1. When manufacturing a conductive rod in which a conductive material with a flat cross section is coated with a corrosion-resistant material, a solid rod of the conductive material is inserted into a corrosion-resistant material tube, and this is pressed at room temperature to perform the first mild flattening press forming. After that, the material is heated in vacuum to the lower recrystallization temperature of the two materials, and a pressure of σ _0.2 or more of the conductive material at that temperature is applied to perform hot forming and diffusion welding. A method for manufacturing a conductive rod, characterized in that a conductive rod having a predetermined shape and size is obtained by performing a second mild flattening finishing press molding in which the flat surface is pressed again after the temperature is lowered to room temperature.