JPH0549941A - Production of metal catalyst carrier - Google Patents

Abstract

(57) [Summary] [Purpose] Simplifies the manufacturing process by uniformly bonding a corrugated plate and a flat plate over a wide range. [Structure] A metal corrugated plate coated with a brazing material and a flat plate are overlapped and rolled up to form a catalyst carrier molded body 3 having alternating layers of the corrugated plate and the flat plate. Ten catalyst carrier molded bodies 3 are electrically connected in series, and a constant voltage is applied from a DC power supply 9. As a result, Joule heat is generated, the catalyst carrier molded body 3 is heated almost uniformly, and brazing is completed.

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 metal catalyst carrier for a catalytic converter of an internal combustion engine.

[0002]

2. Description of the Related Art A corrugated plate made of metal and a flat plate coated with a brazing material are alternately wound around a portion to be irradiated with a laser beam and inserted into a cylindrical case to form a honeycomb catalyst carrier molded body. A step of irradiating the catalyst carrier molded body with a laser beam to form holes and fusing the brazing material around the holes to weld the catalyst carrier molded body, and the holes formed in the cylindrical case in the welding step. A method for producing a metal catalyst carrier including a step of closing by laser brazing is disclosed (see Japanese Patent Laid-Open No. 64-43349).

[0003]

However, in this manufacturing method, in order to weld the inside of the catalyst carrier molded body, it is necessary to form a hole for passing the laser beam through the inside of the catalyst carrier molded body, and After welding, it is necessary to close the perforations formed in the cylindrical case. Therefore,
This manufacturing method has a problem that the manufacturing process is increased and becomes complicated.

[0004] Further, if brazing is attempted in a larger portion in order to improve the strength of the catalyst carrier, there is a problem that the number of manufacturing steps is further increased.

[0005]

In order to solve the above problems, according to the present invention, a molded catalyst carrier having a corrugated plate and a flat plate made of metal and superposed on each other and having alternating layers of the corrugated plate and the flat plate. There is provided a method for producing a metal catalyst carrier, which comprises the steps of: forming a metal catalyst carrier and joining a corrugated plate and a flat plate by passing an electric current through a metal catalyst carrier molded body.

[0006]

When a current is applied to the metal catalyst carrier compact, Joule heat is generated, the whole catalyst carrier compact is heated, and the corrugated plate and the flat plate are joined together.

[0007]

EXAMPLE Referring to FIG. 2, a metal corrugated plate 1 and a flat plate 2
And are overlapped and wound to form alternate layers, and a honeycomb-shaped catalyst carrier molded body 3 is formed. Corrugated plate 1 and flat plate 2
Is a foil material having a composition of, for example, Fe-20Cr-5Al-REM. This metal has a high electrical resistivity like the iron-chromium alloy heating element used as an electrothermal material. Powdered brazing material is previously applied to the portions of the corrugated plate 1 and the flat plate 2 to be brazed by a dipping method or a roll coating method. The brazing material may be plated.

FIG. 3 shows a catalyst carrier molded body 3 formed into a cylindrical shape after the winding is completed. FIG. 4 shows a partially enlarged plan view of the catalyst carrier molded body 3 of FIG. Corrugated plate 1 and flat plate 2
Form alternate layers, and the corrugated sheet 1 and the flat sheet 2 are brazed at the contact portions 4 where the peaks and troughs of the corrugated sheet 1 contact the flat sheet 2.
FIG. 5 shows a brazed region of the cylindrical catalyst carrier molded body. The top surface 3a and the bottom surface 3b of the cylindrical catalyst carrier molded body 3 are brazed. The brazing thickness T is 20 to 30 mm. Only the annular portion 3c is brazed between the top portion 3a and the bottom portion 3b. In this portion, the flat plate 2 is brazed to the corrugated plate 1 in about three layers from the outermost periphery.

In order to carry out such brazing, as shown in FIG. 1, for example, 10 catalyst carrier molded bodies 3 are formed.
Are electrically connected in series and energized. The five catalyst carrier molded bodies 3 are connected in series via the graphite electrode 5, and similarly, the other five catalyst carrier molded bodies 3 are also connected in series via the graphite electrode 5. The graphite electrodes 6 and 7 at the left end are connected to, for example, a DC power supply 9. The right end is connected to one graphite electrode 8. The graphite electrode 8 is pressed toward the left by a constant pressure device 10 so as to give a suitable and substantially constant contact pressure between each catalyst carrier molded body 3 and each graphite electrode 5, 6, 7. . As a result, the catalyst carrier molded body 3 due to thermal expansion
Alternatively, it is possible to prevent the electrodes 5, 6, 7, 8 from being damaged and the contact failure between the catalyst carrier molded body 3 and the electrodes 5, 6, 7, 8 to be prevented.

The voltage of the DC power source 9 is set to a constant voltage of 5 V, for example, and the electric resistance at both ends of one catalyst carrier molding 3 is 3 ×.
If it is set to 10 ⁻⁴ Ω, a current of 1250 A flows. Since the catalyst carrier molded body 3 is made of a metal having a high electric resistivity as described above, Joule heat is generated, the catalyst carrier molded body 3 is heated almost uniformly as a whole, and the brazing material is melted.
After that, it is cooled and all the parts to which the brazing material is adhered can be brazed. This completes the catalyst carrier.

As described above, according to this embodiment, since brazing can be carried out uniformly over a wide range, a catalyst carrier having high strength can be obtained. In addition, in this embodiment, since the brazing can be performed only by energizing the catalyst carrier molded body, the manufacturing process can be simplified. Moreover, since a large number of molded catalyst carrier bodies can be brazed at the same time, productivity can be improved.

Further, since the corrugated plate and the flat plate are not melted during brazing, good brazing can be performed. Although a DC voltage is used as the power supply in this embodiment, an AC voltage may be used. Further, in this embodiment, the voltage is set to a constant value, but the temperature rising / falling speed of the catalyst carrier molded body may be controlled by controlling the voltage.

In this embodiment, the brazing material is used for the brazing in order to bond the corrugated plate and the flat plate, but diffusion bonding may be performed without using the brazing material.

[0014]

By energizing the molded catalyst carrier, the corrugated plate and the flat plate can be bonded uniformly over a wide range, and the manufacturing process can be simplified.

[Brief description of drawings]

FIG. 1 is a diagram showing a state in which a catalyst carrier molded body is energized.

FIG. 2 is a diagram in which a corrugated plate and a flat plate are overlapped and rolled up to form a catalyst carrier molded body.

FIG. 3 is a perspective view of a catalyst carrier molded body.

4 is a partially enlarged plan view of the catalyst carrier molded body of FIG.

FIG. 5 is a view showing a brazing area of a catalyst carrier molded body.

[Explanation of symbols]

 1 ... Corrugated plate 2 ... Flat plate 3 ... Catalyst carrier molded body

Claims (1)

[Claims] 1. A step of forming a catalyst carrier molded body having alternating layers of the corrugated plate and the flat plate by stacking and winding a metal corrugated plate and a flat plate, and the metal catalyst carrier molded body. A step of joining the corrugated plate and the flat plate by passing an electric current therethrough, and a method for producing a metallic catalyst carrier.