JP3204812B2 - Method for producing metal catalyst carrier for exhaust gas purification - Google Patents

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 purifying exhaust gas.

[0002]

2. Description of the Related Art A flat metal sheet and a corrugated sheet are superposed and wound to form a honeycomb cylindrical body formed by bundling a number of parallel through holes defined by the flat sheet and the corrugated sheet.
A metal catalyst carrier for purifying exhaust gas in which this is accommodated and fixed in a metal outer cylinder is known. Conventionally, a method for joining a flat plate and a corrugated plate of a honeycomb cylindrical body has been disclosed in Japanese Patent Application Laid-Open No. 61-199574.
There has been proposed a brazing method as disclosed in Japanese Unexamined Patent Publication (Kokai) No. 63-183, and a laser welding method as disclosed in Japanese Patent Application Laid-Open No. 63-185627.

[0003] However, in the former brazing method, the brazing material reacts with a flat plate or a corrugated sheet to deteriorate heat resistance. In the latter laser welding method, a laser beam is scanned over the entire end face of the honeycomb cylindrical body. There is a problem that it takes a very long time and the cost is high. Although a method of joining flat plates and corrugated sheets by electric discharge machining at both end surfaces of the honeycomb cylindrical body to reduce costs has been proposed, there was a problem that sufficient joint strength could not be obtained by electric discharge machining.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a joint having sufficient strength in a short time without causing deterioration of heat resistance due to brazing material and without requiring a long time for laser beam scanning. It is an object of the present invention to provide a method for producing a metal catalyst carrier for purifying exhaust gas, which can be performed.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided, in accordance with the present invention, a metal plate and a corrugated sheet which are superposed and wound to form a plurality of parallel through-holes defined by the plate and corrugated sheet. Achieved by a method for manufacturing a metal catalyst carrier for purifying exhaust gas, comprising a step of forming a honeycomb tubular body having a bundle of holes and a step of joining a flat plate and a corrugated plate of the honeycomb tubular body by TIG welding. Is done.

[0006]

According to the present invention, since the flat plate and the corrugated plate of the honeycomb cylindrical body are joined by TIG welding, high quality joining can be performed inexpensively and in a short time. The present inventor has made various studies to solve the conventional problems, and as a result, obtained the following new findings and completed the present invention.

In general, a honeycomb cylindrical body constituting a metal catalyst carrier is formed of a foil-shaped thin metal plate. Since this thin plate has a very small thickness of, for example, about 50 μm, if it is to be welded by TIG welding used for welding a normal metal plate, it will be severely melted and will block the air flow passage of the honeycomb cylindrical body. Problems occur. Therefore, conventionally, it was generally recognized that TIG welding cannot be applied to such thin plate welding.

However, the present inventor has found through numerous experiments that a thin plate can be TIG-welded without causing erosion. That is, by using a small electric power which is not used in the TIG welding of a normal metal plate and by appropriately selecting other welding conditions, very stable joining can be performed even with a thin plate of about 50 μm. According to a desirable mode of the present invention, (A) a flat plate and a corrugated plate are joined by TIG welding at an end face of a honeycomb tubular body, or (B) a tungsten electrode for TIG welding is inserted into a through hole, and a honeycomb tubular body is inserted. The flat plate and the corrugated plate inside T
Joined by IG welding.

Hereinafter, the present invention will be described in more detail by way of examples with reference to the accompanying drawings.

[0010]

【Example】

[Example 1] According to the desirable mode (A) of the present invention, a metal catalyst carrier for purifying exhaust gas was produced. As shown in FIG. 1, a ferritic heat-resistant stainless steel foil (thickness 5
0 μm) and a corrugated sheet 3 are overlapped and wound, and an end face 4 is irradiated with a TIG arc to melt only the end face portions of the flat sheet 2 and the corrugated sheet 3, and as shown in FIG. And the flat plate 2 are welded together at a contact point 5 to form a honeycomb cylindrical body 1.
Was formed.

In the TIG welding conditions, the optimum values of the current and voltage are 5 to 20 A and 30 V, respectively, and the arc discharge is interrupted in about 0.1 to 0.2 seconds. The tungsten electrode 6 has a diameter of φ1 mm, the distance 7 between the tungsten electrode 6 and the end face of the honeycomb cylinder 1 is 0.5 to 1.5 mm, and the distance 10 between the high-inert cup 9 of inert gas and the end face of the honeycomb cylinder 1 is 3 to 7 mm. Is optimal.

[0012] TIG welding is not originally performed with such a small electric power, and thus has not been applied to, for example, joining of a thin plate having a thickness of about 50 µm. However, it has been found that by performing TIG welding under the above-described conditions, sufficient strength for forming a honeycomb cylindrical body can be obtained.
The bonding strength of the honeycomb tubular body manufactured by the above method,
The following test evaluated.

FIG. 3 shows the appearance of the test piece. The flat plate 2 having a thickness of 50 μm and the corrugated plate 3 constituting the honeycomb cylindrical body 1 are alternately laminated by 20 sheets. At this time, the first flat plate 2 is sequentially laminated thereon, and another flat plate 2 is further stacked on the last twentieth corrugated plate 3 to form a honeycomb body. This honeycomb body is sandwiched between metal plates 11 (1.5 mm thick) from both sides of the outermost flat plate 2.

Next, a test piece 13 is obtained by TIG welding the end face 12 on which the through holes (air flow passages) arranged in a honeycomb shape are visible under the same conditions as described above. At that time, the TIG welding according to the present invention was performed by two methods, a method of making the arc discharge continuous and a method of making the arc discharge intermittent. Also, TI as a comparative material
A test piece in which the end faces 12 were joined by electric discharge machining instead of G welding was also prepared.

The dimensions of the test piece are a height 14 of 45 mm, a width 15 of 29 mm and a depth 16 of 80 mm. The test piece 13 produced as described above is placed on the lower mold 18 as shown in FIG. Then, the upper end 19 presses the end face 12 of a portion inside the three distances of the corrugated plate 3 downward from the metal plate 11 (in the direction of arrow 17). The pressurizing force is gradually increased, and a load (pull-out load) at which the pressurized inner portion is pulled downward is measured. Lower mold 18 and upper mold 1 used
9 is longer than the depth 16 of the test piece 13.

FIG. 5 shows the detachment load measured by the above test. From this result, it can be seen that a joint joined by intermittent arc discharge by TIG welding can obtain a joining strength twice or more in terms of a detachment load as compared with a joint joined by electric discharge machining. Further, the TIG welding performed by continuous arcing has a strength about 1.5 times as high as that obtained by electric discharge machining, but has an advantage that the operation time can be reduced as compared with TIG welding performed by intermittent arc discharge. [Example 2] According to the desirable mode (B) of the present invention, a metal catalyst carrier for purifying exhaust gas was produced.

As shown in FIG. 6, a tungsten electrode 6 having a portion other than the tip portion 20 covered with an insulating film 21 is coated with a 50 μm thick electrode.
The flat plate 2 and the corrugated plate 3 are inserted into the airflow channel (through hole) 22 of the honeycomb cylindrical body 1 in which the flat plate 2 and the corrugated plate 3 are overlapped and wound, and TIG welding is performed at an arbitrary position inside the honeycomb cylindrical body 1 and the flat plate 2 and the corrugated plate 3 3 is joined. At this time, the TIG welding conditions are such that the optimum values of the current and voltage are 10 to 20 A and 30 V, the discharge time is about 0.1 to 0.2 seconds, and the electrode diameter is φ0.5 to 1.0.
mm, and the thickness of the insulating film 21 is 100 to 200 μm.
Thereby, the flat plate 2 and the corrugated plate 3 can be joined without fusing.

Further, a large number of tungsten electrodes 6 can be used to perform TIG welding at a large number of locations at one time inside the honeycomb cylindrical body.

[0019]

As described above, according to the present invention,
In the production of a metal catalyst carrier for purifying exhaust gas, bonding with sufficient strength can be performed in a short time without causing a deterioration in heat resistance due to brazing material and without requiring a long time for laser beam scanning. Therefore, the manufacturing cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 shows T according to a preferred embodiment (A) of the present invention.
FIG. 3 is a perspective view showing a method of joining a flat plate and a corrugated plate at an end face of a honeycomb tubular body by IG welding. However, the Hyancup section is shown in a sectional view.

FIG. 2 is a plan view showing a joint between a flat plate and a corrugated plate at the end face of the honeycomb tubular body TIG-welded by the method of FIG.

FIG. 3 is a perspective view showing a test piece for a detachment test for evaluating the joining strength of a honeycomb cylindrical body.

FIG. 4 is a cross-sectional view illustrating a detachment test method.

FIG. 5 is a graph showing the pull-out load measured by the test method of FIG. 4 for the honeycomb cylindrical body having the end faces joined by various methods.

FIG. 6 shows T according to a preferred embodiment (B) of the present invention.
It is a perspective view showing a method of joining a flat plate and a corrugated sheet inside a honeycomb cylindrical body by IG welding. However, it shows a state where a part of the honeycomb cylindrical body is cut open.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Honeycomb cylinder 2 ... Flat plate 3 ... Corrugated plate 4 ... Honeycomb cylinder body end surface 6 ... Tungsten electrode 22 ... Air flow path (through hole)

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI B23K 9/167 B23K 9/167 D F01N 3/28 301P F01N 3/28 301 B01D 53/36 ZABC (72) Inventor Akiyoshi Matsuo Aichi 14 Iwatani, Shimohanomachi, Nishio, Japan Pref. (72) Inventor Hiroaki Ichikawa 14th Iwatani, Shimohanomachi, Nishio, Aichi Pref. 1-1-1 Showa-cho, Japan Nihon Denso Co., Ltd. (72) Inventor Keiji Ito 1-1-1, Showa-cho, Kariya City, Aichi Prefecture Nihon Denso Co., Ltd. (72) Kazuyuki Ito 1-1-1, Showa-cho, Kariya City, Aichi Prefecture Address Japan Denso Co., Ltd. (72) Inventor Yasushi Shimizu 1-1-1, Showa-cho, Kariya-shi, Aichi Japan (56) References JP-A-6-307237 (JP, A) JP-A-6-292833 (JP, A) JP-A-63-185627 (JP, A) (58) Fields studied (Int .Cl. ⁷ , DB name) B01J 21/00-37/36 B01D 53/86 B21D 47/00 B23K 9/00 F01N 3/28

Claims (3)

(57) [Claims] 1. A large number of parallel through holes defined by the flat plate (2) and the corrugated plate (3) by superposing and winding a flat metal plate (2) and a corrugated plate (3). (22) a step of forming a honeycomb tubular body (1) in a bundled form, and a step of joining the flat plate (2) and the corrugated plate (3) of the honeycomb tubular body (1) by TIG welding. A method for producing a metal catalyst carrier for purifying exhaust gas, characterized by comprising: 2. The exhaust gas purifying apparatus according to claim 1, wherein the flat plate (2) and the corrugated plate (3) are joined to each other at an end surface (4) of the honeycomb tubular body (1) by TIG welding. A method for producing a metal catalyst carrier. 3. Tungsten electrode for TIG welding (6) is inserted into said through hole (22), and said honeycomb cylindrical body (1).
2. The method for producing a metal catalyst carrier for purifying exhaust gas according to claim 1, wherein the flat plate (2) and the corrugated plate (3) are joined by TIG welding inside the inside.