KR930011710B1 - Metal bed producing method to contain catalyst for purifying exhaust gas - Google Patents

Abstract

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Description

Manufacturing method of metal support matrix for supporting catalyst for exhaust gas purification

1 is a perspective view of a metal support matrix having a laminated structure according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a metal carrying matrix in a state stored in a metal case; FIG.

3 is a perspective view of a metal support matrix having a laminated structure according to another embodiment of the present invention in a metal case;

4 is a perspective view of a triangular cross-sectional shape in which a metal supporting matrix having a laminated structure according to another embodiment of the present invention is accommodated in a case.

The present invention relates to a metal carrier supporting an automobile exhaust gas catalyst. Generally, this is used by installing in the middle of an exhaust pipe as a vehicle exhaust gas purification means. Here, "carvier base material" is different from the "cattier" used in the chemical field, which means a mechanism for holding a catalyst supported by a carrier.

In order to enlarge the area of the carrier per unit volume, that is, it is necessary to expand the effective contact area between the exhaust gas and the exhaust gas purification catalyst per unit volume, and to reduce the weight of the metal carrier itself. Background Art Conventionally, a metal carrier for supporting an exhaust gas purification catalyst has been composed of a spiral or layered chuck layer composed of a plurality of mesh vents through which exhaust gas passes in a constant direction. Flat strips and corrugated strips are made of very thin heat-resistant steel strips with a thickness of 0.1 mm or less, and are laminated to have a contact therebetween. The metal support matrix made of the laminate material as described above may be accommodated in a metal case in which both ends are open. Contact bonding between the strips of the laminate or between the strips and the metal case is made by welding after forming the laminate by electron beam welding or laser welding. These contents are described in Japanese Patent Laid-Open Nos. 45-13462, 57-8585, 56-4373, and the like, and are treated with a powder or a boil-type soldering material, and the like. After formation, it is fixed by soldering.

As the heat-resistant steel strip, for example, a chromium-aluminum-iron type heat-resistant steel containing 15-25% by weight of chromium and 2-5% by weight of aluminum is used. The cost of making the material is high because it is necessary to repeatedly pass the material of the supported parent material to the required thickness through the process of.

In addition, although it is proposed to provide a layer coated with substantially pure aluminum on a base metal of a specific composition as disclosed in Japanese Patent Laid-Open No. 62-11547, such a base metal is not easily obtained.

On the other hand, conventional electron beam welding or laser welding requires special and expensive equipment for assembling and fixing the laminate, and as a result, welding such as narrow contacts or internal contacts becomes difficult and complicated, resulting in productivity. Brings down.

Therefore, in the method of fixing by welding, the shape and arrangement method of the welding material or the heating conditions, etc. should be particularly whaled.

An object of the present invention is to form a metal support matrix by using a specific steel strip, which is easy to roll, in a thin strip, which reduces the production cost, has heat resistance and high temperature corrosion resistance, and at the same time, Another object of the present invention is to provide a metal support matrix for holding a catalyst for exhaust gas purification in which a belt member and a case are fixed.

Briefly, the present invention relates to a method for producing a metal carrier, which supports a catalyst for purifying exhaust gas of a laminated structure. A flat strip of thin steel strips and a corrugated strip of strips are piled up alternately to have a contact portion to form a stack having a plurality of mesh vents in the axial direction, and the stack is then immersed in a molten aluminum bath.

In addition, the second invention also relates to a method of manufacturing a metal carrier supporting a catalyst for exhaust gas purification using a laminate, wherein a plurality of thin steel strips and a corrugated strip are stacked alternately so as to have contact portions. A laminate having a mesh vent hole of was formed, and then the laminate was placed in a cylindrical metal case and then immersed in a molten aluminum bath.

The above-mentioned objects and useful points of the present invention can be clearly understood when considered with the accompanying drawings.

The laminations of Figs. 1 and 2 are wound spirally, while the laminations of Fig. 3 are stacked hierarchically.

In general, an automobile exhaust gas catalytic converter is mounted on the undercarriage of a vehicle. The shape of the base tunnel is usually triangular or trapezoidal in order to reduce the protrusion of the interior floor of the car, and the cross section shown in FIG. 4 is particularly suitable for the complicated shape in the tunnel. In this case, therefore, it is possible to effectively use the space of the tunnel.

It is to be understood that the shape of the metal support matrix according to the present invention is not limited to the exact details shown in these figures.

Flat strips made from thin steel strips used in the present invention are, for example, low carbon steels containing less than about 0.15% by weight of carbon or chromium steels containing less than 0.15% by weight of carbon and 0.15-30% by weight of chromium. The heat-resistant steel sheet or quenched foil is hot rolled or cold rolled to produce a thickness of about 0.03-0.1 mm.

The corrugated strip-shaped member used in the present invention is produced by passing the strip member between forming gears. The plate-shaped band member 1 and the corrugated plate-shaped member 2 thus produced are alternately laminated or spirally wound to form a laminate 5 having a plurality of mesh vent holes 4 in the axial direction. The laminated body 5 cuts strip | belt-shaped material 1 and (2) to a fixed length, and they are produced by stacking them alternately in a hierarchical form.

The laminated body 5 thus produced becomes a metal carrying matrix for supporting the catalyst for purification of exhaust gas. The metal support matrix for supporting the stack 5, i.e., the catalyst for purifying exhaust gas, can be fixed by spot welding if necessary, and can be accommodated in the cylindrical metal case 3 with both ends open.

The laminate 5 is degreased, pickled, and cleaned, and immediately immersed in a molten aluminum bath after flux treatment. After removal from the aluminum bath, the remaining aluminum is removed from the stack 5 by air blasting and then washed with hot water.

The immersion process in the molten aluminum bath is generally performed within about 60 seconds at a temperature of about 700-800 ° C. More preferably, the temperature of the aluminum bath is about 720-760 and the treatment time is within 30 seconds.

In the immersion process of the laminated body 5 in a molten aluminum bath, an aluminum coating layer is formed in the upper and lower surfaces of the strip | belt-shaped material 1 and 2 which consist of laminated bodies. At the same time, during the treatment of aluminum, it is heated to diffuse into the iron to form intermetallic compounds.

The formation of such an iron-aluminum alloy layer is extremely important in the property of improving the heat resistance and high temperature corrosion resistance of the metal carrier.

Moreover, the contact portions between the strip member 1 and 2 are firmly joined to each other by the immersion process of the laminate 5 in the molten aluminum bath. This phenomenon as described above is caused not only by the bonding between the aluminum layers formed on the surface of the strip material, but also by the iron-aluminum alloy layer formed by immersion treatment in the molten aluminum bath and also by the chrome-aluminum alloy layer of the chrome alloy of the strip material. Caused.

According to the present invention, the above-described iron-aluminum alloy layer is continuously diffused by continuously heating in a gas of a reducing or non-oxidizing substance to expand the alloy layer therein in a vacuum or salt bath if necessary. do. It is possible to improve the heat resistance and high temperature corrosion resistance of the metal carrier.

The metal carrier for supporting the exhaust gas purifying catalyst according to the present invention is manufactured by immersing the laminate 5 in a molten aluminum bath as described above. Immersion treatment can be performed not only on the laminate 5 itself but also on the laminate 5 housed in the cylindrical metal case 3.

In this case, the contacts between the strips of the stack 5 and between the stack 5 and the metal case 3 are firmly bonded to each other between the aluminum layers and between the iron-alumina alloy layers.

Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited only to these Examples.

Example 1

A thin steel plate with a thickness of 0.05 mm and a width of 74.5 mm made of low carbon steel [JIS G314 SPCC], and it is passed between the forming gears again. The strips on the corrugated plate processed into a 5 mm wave are alternately superimposed or spirally wound together, and the important points are fixed by spot welding. Therefore, a laminate having an outer diameter of 70 mm having a plurality of mesh bean pores in the axial direction is formed.

The laminate is cleaned by degreasing, pickling, etc., immersed in a molten salt bath composed of lithium chloride, potassium chloride, sodium chloride and sodium fluoride and treated by a flux process. Next, this was immersed in a 740 ° C. molten aluminum bath for 15 seconds, the remaining aluminum was removed by air blasting, and then washed with hot water to obtain a metal carrier having a heat resistant and corrosion resistant coating layer.

Example 2

A thin steel plate of 0.04 mm thickness and 38 mm width made of chrome steel (JIS G 4305 SUS 410 L) (13% chromium). A corrugated strip-shaped member having a wave length of 3.5 mm and a height of 1.8 mm was spirally formed in the same manner as in Example 1. The metal carrier of such a laminated structure is located in a cylindrical case having an inner diameter of about 70 mm. As described in Example 1, immersion treatment in a molten aluminum bath for 12 seconds yields a metal carrier having a heat resistant and corrosion resistant coating layer on its surface.

On the metal obtained in Example 1, the slurry of the active aluminum (gamma aluminum) powder and alumina sol was applied to the surface of the vent of the supported parent and the surface of the vent of the metal supported parent obtained in Example 2. By heating, the catalyst carrier layer is attached to the surface of the vent hole of the metal carrier. The sample thus obtained was subjected to rapid cycles of rapid quenching and quenching at 50 cycles between room temperature and -700 ° C. As a result, no cracks or peelings were observed at the joints and coating layers of the samples. This test confirmed that the metal carrier according to the present invention had excellent heat resistance and impact resistance.

In the present invention, the strip member constituting the support carrier made of metal is a low carbon steel or chromium steel die, which can be easily rolled and obtained at a relatively low value.

It disperse | distributes and coat | covers with aluminum on the surface of the strip | belt-shaped material which comprises the metal carrier matrix of this invention by immersion treatment in a molten aluminum bath. At the same time, alloy layers containing an aluminum alloy such as iron-aluminum intermediate compound are formed. Such coating layers have excellent heat resistance and high temperature corrosion resistance. The contacts between the laminated strips or between the strips and the metal case are firmly fixed to each other with this coating alloy layer. Thus, a separate welding or soldering process can be omitted.

Claims (24)

The plate-like strip and the plate-shaped strip formed of thin steel strips are alternately stacked to have a contact portion to form a laminate having a plurality of mesh vents in the axial direction, and then the laminate is immersed in a molten aluminum bath. A method for producing a support matrix in metal for supporting a catalyst for purification of exhaust gas of a laminated structure, characterized in that the. The method of claim 1 wherein the thin steel strip is low carbon steel or chromium steel. The method of claim 2 wherein the low carbon steel contains 0.15% by weight of carbon. The method of claim 2 wherein the chromium steel contains 0.15 wt% carbon and 0.15-30 wt% chromium. The method of claim 1 wherein the thickness of the thin steel strip is about 0.03-0.1 mm. The method of claim 1 wherein the laminate is wound in bundles. The method of claim 1 wherein the laminates are stacked hierarchically. The method according to claim 1, wherein the contact portion between the flat strip and the corrugated strip is joined to a spot. The process according to claim 1, wherein the immersion treatment is carried out in a molten aluminum bath at a temperature of 700-800 ° C. The method according to claim 1, wherein the immersion treatment is performed in a molten aluminum bath within 60 seconds. The method of claim 1 wherein the immersion treatment is performed in a molten aluminum bath at about 720-760 ° C. within about 30 seconds. The method according to claim 1, wherein after the laminate is immersed in a molten aluminum bath, residual aluminum is removed by air blasting and then hot washed. The plate-shaped band member made of thin steel band and the corrugated plate-shaped member are alternately stacked to have a contact portion to form a laminate having a plurality of mesh vents in the axial direction, and then the laminate is housed in a cylindrical metal case. A method of manufacturing a metal carrier matrix for supporting an exhaust gas purification catalyst of a laminated structure housed in a cylindrical metal case, which is immersed in a molten aluminum bath afterwards. The method of claim 13, wherein the thin steel strip is low carbon steel or corium steel. 15. The method of claim 14, wherein the low carbon steels incorporate 0.15 weight percent carbon. 15. The method of claim 14, wherein the chromium steel contains 0.15 weight percent carbon and 0.15-30 weight percent chromium. The method of claim 13, wherein the thin steel strip is about 0.03-0.0.10 mm thick. The method of claim 13, wherein the laminate is wound in a bundle. The method of claim 13, wherein the laminates are stacked hierarchically. The method of claim 13, wherein the contact portion between the flat strip and the corrugated strip is joined by spot welding. The process according to claim 13, wherein the immersion treatment is carried out in a molten aluminum bath at a temperature of 700-800 ° C. The method according to claim 13, wherein the immersion treatment is performed in a molten aluminum bath within 60 seconds. The method according to claim 13, wherein the immersion treatment is performed in a molten aluminum bath within about 30 seconds at a temperature of 720-760 ° C. The method of claim 13, wherein the laminate is immersed in a molten aluminum bath, the remaining aluminum is removed by air blasting and then washed with hot water.

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