JPS5842793B2 - Brazing material for diffusion bonding and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brazing material for diffusion bonding and a method for manufacturing the same, and more particularly, to a soldering material for diffusion bonding that allows base materials to be easily joined with extremely high precision without shifting the relative positions of the base materials. Concerning brazing material and its manufacturing method.

BACKGROUND ART Recently, various machines and parts have become more complex and demands for higher precision have increased, and therefore, advanced joining techniques for various parts are being developed.

Among the many joining techniques, brazing is a method that can also be used to join internally, which is impossible to do directly from the outside as seen in customer service. It is widely applied for joining.

This brazing method involves interposing a brazing material between the base materials to be joined, which has a lower melting point than the base materials and generally has a different material composition from the base materials, and heats the joint to a predetermined temperature. After melting and fluidizing the brazing material and sufficiently distributing it to the joint,
This method involves cooling and solidifying it.

Therefore, the working temperature of the members joined by this method is naturally below the melting point of the brazing material used for joining,
Moreover, there is an essential constraint that the mechanical strength of the joint is determined by the strength of the brazing material.

The diffusion bonding method was developed to solve these problems.

This method uses a brazing material (diffusion bonding brazing material) that has substantially the same material composition as the base material to be joined, and applies the principle of liquid phase diffusion.

As such a brazing material, for example, Metglass MFB80 (trade name), which contains N1jCr as a main component and contains B, Si, P, etc. as melting point lowering elements, is known.

An example of the method is as follows.

First, cut the brazing material to match the joining surface of the base materials to be joined.
Processing (Step 1), Next, the brazing material is placed on the joint surface of the base metal (Step 2), The whole is placed in a predetermined pressing die (Step 3), Then the whole is placed in a furnace at a predetermined temperature. to melt the brazing material (step 4), hold it at that temperature for a predetermined time,
This process consists of a series of steps in which the base materials are bonded by liquid-phase diffusion of molten brazing filler metal into the base materials (step 5).

In step 5, isothermal solidification of the brazing material occurs.

According to this method, the brazing metal diffuses into the base metal in a liquid phase and solidifies isothermally, so the resulting joint has a composition that is almost the same as that of the base metal, and therefore its heat resistance, mechanical strength, etc. It is comparable to that of .

In other words, the material properties of the joint become more excellent.

However, a major problem with this method is that it requires a high-precision press die and its ancillary equipment in order to improve the joining accuracy between the base materials.

The brazing material is completely melted in step 4.

Therefore, the base materials can move horizontally or vertically relative to each other.

In order to improve the dimensional accuracy of the joint, it is necessary to suppress the movement of the base material in this floating state.

This is because the type is used for that purpose.

As the shape of the joint becomes more complex, the molds used also become more complex, and when the base materials to be joined have a variety of different shapes, the molds must be individually adapted to suit them.

The present inventors have focused on the fact that the above-mentioned drawbacks of the diffusion bonding method are due to the movement of the base material due to melting of the brazing material.

However, on the other hand, we also focused on the isothermal solidification phenomenon in which the liquid phase diffusion of molten brazing material into the base metal causes the liquid phase temperature to shift to a higher temperature side as time passes, and by making effective use of this phenomenon. We have developed a brazing material for diffusion bonding that does not cause movement of the base material, and a method for manufacturing the same.

The present invention provides a brazing material for diffusion bonding and a method for manufacturing the same, which eliminates the need to use a press die because the base materials to be joined do not move freely, and which can easily join the base materials with high precision. It has a purpose.

The brazing material of the present invention has an integral structure in which thin strips of two types of brazing materials with different melting points are alternately connected in the band width direction, and the method for manufacturing the brazing material is as follows: Two types of brazing materials having different melting points are melted separately; each of the molten brazing materials is passed through a plurality of nozzles provided in the container, each of which is arranged alternately in a row. It is characterized by simultaneously injecting and cooling the rotating surface of the rotating body from the nozzle group.

FIG. 1 shows an example of the brazing material of the present invention as a partially cutaway perspective view.

In the figure, 1.1' are brazing materials with different melting points (
Thereafter, the brazing material 1 will be replaced with a low melting point brazing material (melting point T1) and the brazing material 1.
' is called a high melting point brazing material (melting point T2).

) thin strip. As shown in the figure, a plurality of thin strips are alternately and consecutively integrated along the width direction of the strip.

The figure shows an example in which two thin strips of each type are installed in a row, a total of four strips.
The brazing material of the present invention is not limited to this, and the number of thin strips may be any number as long as two types of thin strips having different melting points are alternately joined in the width direction of the strip.

The brazing material of the present invention is used for diffusion bonding as follows.

That is, the brazing material is interposed between the joining surfaces of the base materials to be joined, and the entire body is inserted into a vacuum hot press, for example, and pressure is applied between the base materials, so that the brazing material is inserted between the joining surfaces. Fixed to.

At this time, at the contact interface between the base material and the brazing material, microscopically, the two are in a point contact state.

Next, the joint is heated to a temperature higher than T1 and lower than T2, and held at this temperature for a predetermined period of time.

The brazing material 1 melts into a liquid state, and changes from a point contact state to a surface contact state with the base metal, increasing the contact area between the two.

The brazing material 1' does not melt but exists in a solid state, and maintains a point contact state with a small contact area with the base material.

As time passes, the melted brazing material 1 diffuses into the base material through the contact interface with the base material in a surface contact state, and as a result, isothermally solidifies and its liquidus temperature T3 increases.

On the other hand, at this time, the melting point depressant in the brazing material 1' also shows a tendency to diffuse into the base material, but as mentioned above, the brazing material' and the base material are in point contact and there is a gap between them. Since the contact area is extremely small, there is virtually no diffusion of the melting point depressant into the matrix.

When T3 becomes sufficiently larger than T2, the joint is
2 and lower than T3 and held at that temperature for a predetermined time.

The brazing material 1' melts, but the brazing material 1, which has undergone liquid phase diffusion, does not melt and remains in a solid state because T3 is higher than T2.

As time passes, the molten brazing material 1' diffuses into the base metal in a liquid phase and solidifies isothermally.

If the base materials are diffusion bonded using the brazing material of the present invention, as is clear from the above explanation, the brazing material 1
Either the brazing material 1' and the brazing material 1' are in a solid state and do not melt at the same time, so there is no movement of the base material.

Therefore, without using a pressing die, the base materials can be joined in the same state as when they were set.

Therefore, the accuracy of the joining increases naturally.

The brazing material of the present invention can be manufactured as follows.

FIG. 2 is a conceptual diagram showing an example of an apparatus for producing the brazing material of the present invention. Reference numeral 11° and 11' denote a container made of a heat-resistant material such as quartz glass; The raw materials for different brazing materials are stored separately.

A heating means 12 such as a high frequency heating coil is disposed around the container 11, 11', and the raw material is melted by activating the means.

13 and 13' are melted brazing materials having different melting points.

At the bottom of the containers 11 and 11', there are multiple tubes (3 each in the figure).
(book) nozzles 14a, 14b, 14c, 14'a.

14'b and 14'c are provided.

Each nozzle is, for example, 14a, 14'a, 14 as shown in the figure.
b.

14'b, 14c, and 14'c are alternately arranged in parallel (in the figure, they are a horizontal line).

). Reference numeral 15 indicates a valve for supplying the molten brazing filler metals 13 and 13' from the containers 11° and 11' to the corresponding nozzles, respectively.

A rotating body 16, such as a copper roll, is disposed at a predetermined distance below each of the parallel nozzles and rotates in the direction of arrow P.

The molten brazing filler metals 13 and 13' are injected from each nozzle onto the rotating surface of the rotating body 16 by gas press-injected from a gas injection device (not shown) airtightly connected to the upper open end of the container 11, 11'. and then cooled quickly.

At this time, by appropriately selecting the distance between the nozzles, the speed of the rotating body, the injection amount, etc., the thin pieces of brazing material injected from each nozzle can contact each other on their sides and be rapidly cooled as they are. As a result, it is possible to continuously manufacture an integrated brazing material 17 in which the ribbons are alternately connected in the width direction.

Note that although the figure shows an example in which one container is provided with three nozzles, the aspect of the apparatus is not limited.

In short, the brazing material of the present invention can only be produced by alternately arranging nozzles that inject two types of brazing materials having different melting points in parallel.

The present invention will be explained below based on examples.

Example The apparatus shown in FIG. 2 was assembled.

The cross-sectional shape of each nozzle opening is 3 am long and 0.4 am wide.
7! It was a rectangle of m.

These nozzles are arranged in a zigzag pattern, staggered back and forth by a length corresponding to the thickness of the nozzle wall, and are arranged side by side so that the opening of each nozzle is substantially continuous across its width. It is being

Further, the distance between the nozzle and the roll was 0.2 mm.

First, the composition of the container 11 is N i -15,2Cr-4B.
(melting point 1065°C), the composition of the container 11' is Ni.
-7Cr-3Fe-4,58i-3,2B (melting point 100
0° C.), and the high-frequency heating coil 12 was activated to heat the brazing material to 1350° C. to melt the entire amount.

Next, a gas pressure of 0.2 atm is applied to the molten brazing material 13, 13' using argon gas, the valve 15 is opened, and the molten brazing material is poured from each nozzle onto the rotating surface of the copper roll 16 rotating at 200 rpm. ejected.

A braze material strip 17 having an integral structure in which thin strips having different melting points were alternately connected was obtained.

The thickness was 35 μm. Next, this band of brazing material is sandwiched as it is between parts made of Ni-based superalloy lN738, and the entire part is completely zeroed without using a mold to hold the parts.
．． Applying pressure of 3kg//Im2 in the vertical direction, 2X1
In a vacuum of 0-5 Torr, heat treatment was first performed at 1010°C for 1 hour, and then at 1070°C for 1.5 hours.

There was no deviation in the relative position between the parts, and extremely high-precision joining was possible.

As is clear from the above description, the brazing material of the present invention has great industrial value because it enables highly accurate diffusion bonding without using a press die.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of an example of the brazing material of the present invention, and FIG. 2 is a conceptual diagram showing an example of an apparatus for manufacturing the brazing material of the present invention. 1... Thin strip of low melting point brazing material, 1'... Thin strip of high melting point brazing material, 11, 11'... Container, 12... Heating means (high frequency heating coil), 13.13' ...Melted brazing filler metal, 14a to 14c, 14'a to 147c...
Nozzle, 15... Valve, 16... Rotating body, 17...
Brazing material of the present invention, P... An arrow indicating the rotation direction.

Claims (1)

[Scope of Claims] 1. A brazing material for diffusion bonding having an integral structure in which thin strips of two types of brazing materials having different melting points are alternately connected in the width direction of the band. 2. In each of a plurality of heat-resistant containers, two types of brazing materials having different melting points are separately melted; 1. A method for producing a brazing material for diffusion bonding, which comprises simultaneously injecting onto a rotating surface of a rotating body and cooling it from a plurality of nozzle groups arranged in parallel.