JPS63157760A - Manufacture of metal bellows - Google Patents

Abstract

PURPOSE:To eliminate the loss generation of a brazing filler metal and to facilitate its overlapping by performing a screen process printing of the paste like brazing filler metal consisting of a brazing filler metal powder and resin binder on the surface of the outer peripheral edge part and inner peripheral edge part of a mutually joining annular metal. CONSTITUTION:Step parts 5, 6 are respectively provided on a 1st annular metal 1 so as to locate at the inside of the same plane of are inner peripheral edge part 1a and outer peripheral edge part 1b and a wavy shaped projection 4 is formed so as to locate at one side of this plane. A 2nd annular metal 2 is formed flatly so that the inner peripheral edge part 2a and outer peripheral edge part 2b are located in the same plane 8 and the wavy projection 4 is formed so as to locate at one side of the plane 8. Each metal plate 1, 2 is taken as the stainless steel plate in about 0.1mm thickness. The paste like brazing filler metal consisting of a brazing filler metal powder and resin binder is printed by a screen method on the step part 5 surface of the inner peripheral edge part 1a of the metal plate 1 and the surface of the outer peripheral edge part 2c of the outer peripheral edge part 2b of the metal plate 2 and the part joining by overlapping each other is joined by its heating with pressure. A metal bellows is thus made easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method of manufacturing an accordion-shaped metal bellows used as an expansion pipe joint, a heat exchange element, etc.

(Prior Art) Conventionally, as described in Japanese Patent Publication No. 45-39172, a method for producing metal bellows of this type has been used to produce metal bellows between the outer and inner edges of a plurality of stacked annular metal plates. Annular brazing filler metals are alternately inserted between the sections, and the stacked annular metal plates are joined by the brazing filler metal at alternate outer and inner edges by heating and melting the filler metal to form a bellows shape. It is known to bond together.

In the above-described conventional method for manufacturing metal bellows, an annular brazing material is used, which is cut into a predetermined annular shape from a thin plate of a brazing material such as nickel brazing material, copper brazing material 1, or aluminum alloy brazing material.

(Problems to be Solved by the Invention) However, as described above, there is a problem in that as a result of cutting out a predetermined ring-shaped brazing material from a thin plate of brazing material, material loss of expensive brazing material occurs. In addition, since it is necessary to insert and hold thin circular metal plates precisely in a predetermined position between overlapping circular metal plates, stacking the circular metal plates becomes labor-intensive and difficult to stack. There were problems such as the need to use a special jig.

The present invention aims to solve such conventional problems.

(Means for Solving the Problems) According to the present invention, a plurality of annular metal plates are stacked one on top of the other, and the distance between the outer circumferential edges and the inner circumferential edges of the stacked annular metal plates to be joined to each other is alternately When manufacturing bellows by bonding with brazing filler metal, a paste-like brazing filler metal made by kneading brazing filler metal powder and a resin binder is applied to the surfaces of the outer and inner edges of the annular metal plates to be bonded together using a screen printing method. It is characterized by printing.

(Function) According to the present invention, by printing a paste-like brazing material on the surface of the outer peripheral edge or inner peripheral edge of an annular metal plate by screen printing, the soldering material can be applied to a desired thickness within a predetermined range. It can be precisely provided integrally with the annular metal plate. Therefore, the work of stacking the annular metal plates is simplified, and not only can a simple jig be used, but also the above-mentioned material loss of the brazing filler metal can be eliminated.

As the brazing filler metal powder, a conventionally known suitable material can be selected and used depending on the material of the annular metal plates to be joined. For example, when the annular metal plate is stainless steel, for example, Ni-19Cr-10Si, G
o −17Ni −19Cr −4W −0,8B −
Ni-based, CO-based alloy powder such as 88i can be used. The particle shape of the brazing filler metal powder is usually spherical, but particles other than spherical can also be used by adjusting the blending ratio with the resin binder. Further, the powder particle size is preferably about 250 mesh or less (63 μm or less).

As the resin component as a binder, it is preferable to use a thermoplastic resin such as acrylic. It is preferable to use a resin that decomposes in a hot process and does not leave impurities such as yIi released carbon.

The blending ratio of brazing powder and resin binder is 75-95% by weight of brazing powder and 25-5% by weight of resin binder.
% is preferred. This blending ratio varies depending on the type and particle shape of the brazing filler metal powder, but the blending ratio of the resin binder is 2 by weight.
If it exceeds 5%, brazing properties may be impaired, which is not preferable. Further, if this blending ratio is less than 5% by weight, the paste will not be sufficiently formed, and the adhesion to the surface will be poor in brazing, making printing impossible.

A good pattern can be obtained without clogging when the opening of the screen used for printing is about three times the maximum particle diameter of the powder. Further, it is preferable to apply an emulsion to the area of the screen other than the area to be printed in advance to seal the area. The thickness of the brazing material printed on the surface can be freely controlled by adjusting the thickness of the emulsion applied to the screen.

By using the screen printing method, it is possible to cover and braze the paste-like brazing material at a predetermined location on the surface with only the necessary amount of strength, which saves on the brazing material and is economically advantageous.

〔Example〕

An embodiment of the invention will be described with reference to the drawings.

In the illustrated embodiment, the metal bellows are comprised of two types of plurality of first
An example is shown in which the second annular metal plates 1.2 and 1.2 are stacked alternately. The first and second annular metal plates 1.2 are both press-molded from approximately 0.111 stainless steel plates, have an outer diameter of 621 mm, a center hole 3 with an inner diameter of 33 u, and a wave-shaped protrusion 4 between the inner and outer peripheries. is formed by extending in the circumferential direction,
As a result, a plurality of concentric annular irregularities are provided.

As shown in FIG. 2, the 11th jt-shaped metal root 1 has an inner circumferential edge 1a and an outer circumferential edge 1b for reasons described below.
Step portions 5 and 6 are provided respectively. The surfaces of these stepped portions 5 and 6 are located in the same plane 7, and the wave-shaped protrusion 4 is located on one side of this plane 7, that is, the wave-shaped protrusion 4 is formed so as not to protrude from one side of the plane 7. ing.

As shown in FIG. 3, the second annular metal plate 2 has an inner circumferential edge 2a and an outer circumferential edge 2b that are both flat, and are not provided with a step. One side of the inner circumferential edge 2a and the outer circumferential edge 2b are located within the same plane 8, and similarly to the annular metal plate 1, the corrugated protrusion 4 is formed so as to be positioned on one side of the plane 8.

2 and 3, 9 and 10 are on the surface of the stepped portion 5 at the inner peripheral edge 1a of the annular metal plate 1 and on the surface of the outer peripheral edge 2C of the outer peripheral edge 2b of the annular metal plate 2. A brazing filler metal printed by a screen printing method is shown.

As shown in the figure, in order to print the brazing fillers 9 and 10, the brazing filler metal powder is 250 meshes or less (63 μm or less).
Ni -70r -3,2B -4,5Si -3F
e powder was used. 95% by weight of this brazing filler metal powder and 5% by weight of a resin binder were kneaded.

(The pasted brazing filler metal is printed on the stepped portion 5 of the annular metal plate 1 and the outer peripheral edge 2C of the annular metal plate 2 along the planes 7 and 8 by screen printing using a screen with an opening of 70 meshes. It was printed on the surface to a thickness of 100 μm.

As shown in FIGS. 2 and 3, paste brazing filler metal 9
The annular metal plates 1 and 2 on which the numbers 1 and 10 are printed on the inner peripheral edge 1a and the outer peripheral edge 2b, respectively, are stacked alternately as shown in FIG. An end plate was installed at the outer end, and the parts to be joined were pressurized from both sides in the overlapping direction, and joined by heating in a vacuum heating furnace. A part of the metal bellows obtained by expanding after joining is shown at 11 in FIG.

In order to easily print the pasty brazing material by the screen printing method described above, the flat surfaces 7 and 8 including the printing surfaces of the annular metal plates 1 and 2 are positioned on one side of the corrugated protrusion 4. It is preferable to do so. Further, as in the illustrated example, it is preferable to use two types of annular metal plates 1 and 2 and to provide step portions 5 and 6 on the inner and outer peripheral edges 1a and 1b of one of the annular metal plates 1. As a result, when the annular metal plates 1 and 2 are overlapped, as shown in FIG.
3 is formed. These voids 12, 13 prevent the molten brazing material from seeping out due to capillary action, thereby ensuring the required brazing width.

(Effects of the Invention) According to the present invention, it is possible to eliminate the loss of brazing filler metal and to easily perform the work of stacking annular metal plates before the heating and melting process.

[Brief explanation of the drawing]

Fig. 1 is a plan view of an annular metal plate integrally provided with printed brazing material, Fig. 2 is an enlarged partial vertical cross-sectional view taken along line I[-II in Fig. 1, and Fig. 3 is a brazing material. Figure 4 is an enlarged partial vertical sectional view similar to Figure 2 of the second annular metal plate printed and provided integrally with the first and second annular metal plates shown in Figures 2 and 3. FIG. 5 is an enlarged partial vertical cross-sectional view showing a state in which the metal bellows are superimposed on the metal bellows. FIG. 1.2... Annular metal plate 1a, 2a... Inner peripheral edge 1b, 2b... Outer peripheral edge 3... Center hole 4... Wave-shaped protrusion 5, 6... Step portion 7.8 ···Plane
9,10...Printed brazing material Figure 2

Claims (1)

[Claims] 1. When manufacturing a bellows by stacking a plurality of annular metal plates and joining the outer and inner edges of the stacked annular metal plates that are to be joined to each other using a brazing material, A method for manufacturing a metal bellows, which comprises printing a paste-like brazing filler metal, which is a mixture of brazing filler metal powder and a resin binder, on the outer and inner circumferential edges of annular metal plates to be joined using a screen printing method.