JPS63299875A - Method for joining metal structural body - Google Patents

Abstract

PURPOSE:To form a firm joining part with fine cleanness of sheet metals without brazing by forming one sheet metal to a welded structural body with pressure which is corrugated mechanically and joined together and heating and maintaining it in the specific temperature range in an unoxidizing atmosphere. CONSTITUTION:One sheet metal 12 at least between the sheet metals 12 and 20 which are cold-rolled or quenched and solidified is bitten between corrugating rollers and formed to a corrugated sheet 16 and rolled up to the metal structural body 22 and welded together with pressure. The structural body 22 like this is heated at 840-1,400 deg.C in a gas atmosphere such as inert gas or N2, etc., and maintained for about 30min-8hr. A contact part is subjected to the atomic diffusion sufficiently and creep deformation properly and the metal structural body 22 can be formed to a firm welded zone without using brazing by a brazing method and without spoiling the wear resistance.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for joining metal structures formed from thin sheets formed by cold rolling and rapid solidification, and more specifically, to a method for joining metal structures formed from thin metal sheets formed by cold rolling and rapid solidification. The structure is covered with inert gas or N,
This invention relates to a method of diffusion bonding the contact portions of ribbons by heating and holding in an H gas atmosphere without using a plating sheet.

[Prior Art] A honeycomb-like structure made up of hexagonal columns and other cell shapes is also called a honeycomb structure, and has the characteristics of being lightweight and having high rigidity. Furthermore, when this structure is used as a carrier as it is, various properties can be obtained,
This structure has a particularly excellent rectifying effect when placed in a fluid, and since it is partitioned by small cells, the wall area is much larger than the volume, allowing for a large contact area with air and water. Therefore, it is used as a catalyst structure.

There are two methods used to manufacture this honeycomb metal structure: a stretch method and a corrugate method. The stretching method involves applying adhesive to the material in a line, cutting it to an appropriate length, stacking several sheets, applying pressure and heat to harden the adhesive, slicing it to an appropriate thickness and stretching it. It has a honeycomb shape. The corrugating process is usually applied to produce dense honeycombs that cannot be expanded. First, roll the material into a corrugated roll (
After applying adhesive to the crests of the corrugations, stacking a large number of corrugated sheets, and applying a load in the stacking direction, they are heated and bonded. Furthermore, in the corrugation method, flat plates of the same width are stacked on top of a corrugated sheet that has been folded with a corrugated roll, rolled up into a roll shape while stacked, rolled to a predetermined size, and then the corrugated peaks of the corrugated sheet There is a method of manufacturing a honeycomb structure by joining the troughs to a flat plate by brazing or the like. The present invention relates to a corrugating method in which a corrugated sheet and a flat plate are overlapped, rolled into a roll, and bonded.

Among the conventional manufacturing methods for honeycomb structures, in the method of overlapping a corrugated sheet and a flat plate and rolling them into a roll to join the corrugated sheet and flat plate, the corrugated sheet and flat plate are coated with a material for brazing. Using a plating sheet, the corrugated sheet and the flat plate were brazed together by rolling it into a roll and heating it. However, this conventional method of joining corrugated sheets and flat plates by brazing is expensive because it uses plating sheets, and brazing has the disadvantage of deteriorating the corrosion resistance of the parts. Another problem was that the surface of the flat plate was oxidized and corrosion progressed quickly to the inside.

[Problems to be Solved by the Invention] The present invention relates to a method for manufacturing a metal structure having a honeycomb structure, in which a corrugated sheet and a flat plate are overlapped and rolled into a roll to join the corrugated sheet and the flat plate. This was done in view of the problems such as: It is possible to reduce costs without using a plating sheet, and also to join a corrugated sheet and a flat plate without using brazing or oxidizing the surface of the plate. The purpose of this research is to provide a method for joining metal structures that is possible.

[Means for Solving the Problems] The present inventor has discovered that when a corrugated sheet and a flat plate are overlapped and rolled into a roll, the cohesive force acts between the atoms of the corrugated sheet and the atoms of the flat plate. Focusing on the fact that they are in close contact, they discovered that solid-phase bonding is possible, and also came up with the idea of heating in an inert gas atmosphere to prevent oxidation of the structure, and developed the present invention. It has been completed.

That is, the method for joining metal structures of the present invention uses a thin plate formed by cold rolling or rapid solidification as a material,
mechanically deforming at least one of the thin plates to increase the surface area, and then combining the thin plates to form a gold iX ellipse, and joining the thin plates at the contact portions of the structure; The metal structure is heated and held at 850 to 1400°C in an inert gas or N, H gas atmosphere, and the ti
The gist is to diffusion bond the structure contact portion.

The thin plate used in the present invention is preferably a thin plate formed by cold rolling or rapid solidification with excellent surface cleanliness and smoothness of about 10 to 500 microns, and in the present invention, at least one of the thin plates has an increased surface area. The mechanical deformation for this purpose may be any shape such as a wavy shape, a bent shape, or a pleated shape.

[Action co-diffusion bonding mainly utilizes atomic diffusion and creep deformation to achieve close contact between bonding surfaces. Since diffusion bonding is an interfacial phenomenon, the surface condition is naturally important. Possible joining condition factors include construction factors such as surface treatment, temperature, time, and pressure, as well as mechanical or metallurgical factors of the materials.

Diffusion bonding requires stricter surface cleaning and smoothing than other bonding methods.The cleaner and smoother the surface, the more it can be bonded at lower temperatures and pressures. In the present invention, when the corrugated sheet and the flat plate are overlapped and wound into a roll shape, the contact portion between the corrugated sheet and the flat plate is in close contact to the extent that a cohesive force acts between atoms, and Among thin plates, thin plates formed by cold rolling have particularly excellent surface cleanliness and smoothness, and have sufficient smoothness for diffusion bonding. Furthermore, since the cleaned contact surface is kept in an inert gas or I(,N) atmosphere during heating, contamination of the surface can be avoided.

The material constituting the metal structure may be an iron-based, Ni-based, or Co-based material, and if it is iron-based, for example, austenitic stainless steel or ferritic stainless steel is used. The thickness of the board should be around 40μ, but
It doesn't matter if it's thicker than this.

In the present invention, the bonding temperature is 850 to 1400°C. This is because when the bonding temperature is less than 850°C, the atomic diffusion rate and Cree-1 deformation are not sufficient, and a satisfactory bond cannot be obtained.If the bonding temperature exceeds 1400°C,
This is because the shape of the metal structure is deformed. Heating is performed in an inert gas atmosphere, and Ar gas, N, or H gas is used as the inert gas.

The bonding time is an important factor that influences atomic diffusion and creep deformation, and although it varies depending on the material and type of product, it is preferably about 30 minutes to 8 hours.

That is, in order to obtain sufficient tensile strength, a holding time of at least 30 minutes is required, and further improvement in strength cannot be expected even if held for 8 hours or more.
For a structure made of austenitic stainless steel with a thickness of 40 μm, the heating time is 1.5 hours at 1100°C, and for ferritic stainless steel, the heating time is about 5 hours at 1100°C.

Bonding pressure is an important factor along with temperature and time, and it not only affects the destruction and adhesion of the surface film, but also promotes atomic Q diffusion and creep deformation. In the rolled-up state, the corrugated sheet is deformed by the rolling-up,
Due to the restoring force, the corrugated sheet and the flat plate are brought into close contact with each other under moderate pressure.

[Examples] Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view schematically showing the manufacturing process of a metal structure. In FIG. 1, a first thin plate coil 10 and a second thin plate coil are made of Fe-Cr formed by cold rolling.
- Plate thickness of ferritic stainless steel made of Al alloy: 4
It is a thin plate with a surface roughness of 0.5μ.

The thin plate 12 pulled out from the first thin plate coil 10 is bitten by a pair of corrugated rollers 14 rotating in the direction of the arrow, and comes out as a corrugated sheet 16.

The second thin corrugated sheet 18 has the same width as the first thin coil, and the thin plate pulled out from the second thin coil 18 remains a flat plate 20 and is overlapped with the corrugated sheet 16. 16 and the flat plate 20 are wound up into a roll to form a metal TLL structure 22 having a honeycomb structure.

The obtained metal structure 22 was placed in a heating furnace maintained in an N2 atmosphere, heated to 1100° C. and held for 1.5 hours, and the corrugated sheet 18 and the flat plate 20 were diffusion bonded. When we examined the bonded state of the gold structure 22 taken out from the heating furnace, we found that the corrugated sheet 18 and the flat plate 20 were completely bonded together, and when we pulled to separate the bonded portion, the bonded portion came off. It was confirmed that the corrugated sheet 16 and the flat plate 20 were completely joined together, with the plate breaking at a weak part without any cracking.

In addition, ferritic stainless steel (SUS430), austenitic stainless steel (SUS310), soft iron and I neone with the plate thickness and surface roughness shown in Table 1
751, the materials are completely diffusion bonded by heating temperature and holding time shown in Table 1, respectively.
It was confirmed that the strength of the joint was greater than the strength of the materials, and that it was possible to join the metal structures shown in Table 1.

Table 1 [Effects of the Invention] As explained above, the method for joining metal structures of the present invention is a method for joining metal bodies made by overlapping corrugated sheets and flat plates folded into a wave shape and rolling them into a roll. The metal structure was heated for 850 minutes in an inert gas atmosphere.
This method heats and maintains the corrugate sheet and flat plate at ~1400°C and diffusion-bonds the corrugated sheet and flat plate. Since there is no need to braze the corrugate sheet and flat plate, there is no need for brazing and the cost is low, and brazing is done only partially. Since there are no cracks, corrosion resistance is not impaired, and the plate materials that make up the structure have good cleanliness, and a strong joint can be obtained, which is an excellent effect.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating the manufacturing process of a metal structure. 16... Corrugated sheet, 20... Flat plate, 22...
...Metal structure. Figure 1

Claims (1)

[Claims] (1) Using a thin plate formed by cold rolling or rapid solidification as a material, mechanically deforming at least one of the thin plates to increase the surface area, and then combining the thin plates to form a metal structure, To bond the contact portions between the thin plates of the structure, the metal structure is heated and held at 850 to 1400°C in an inert gas or N, H gas atmosphere, and the contact portions of the structure are diffusion bonded. A method for joining metal structures, characterized by: