JP2003117685A - Composite brazing filler metal, composite material for brazing, and brazed product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new composite brazing filler metal which has excellent heat resistance and corrosion resistance, and has satisfactory brazing operability and excellent joining strength, to provide a composite material for brazing, and to provide a brazed product. SOLUTION: The composite brazing filler metal consists of a stacked body obtained by stacking a nickel layer consisting of nickel or a nickel alloy, and a non-nickel layer consisting of titanium, manganese, tin, zinc, aluminum, copper or their alloys. Thus, the composite brazing filler metal can exhibit excellent heat resistance and corrosion resistance, can therefore maintain excellent joining strength, and further, has satisfactory fluidity compared with a nickel simple substance, and is made easy to be treated compared with the powdery one, so that its brazing operability remarkably improves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite brazing material suitable for producing a brazing product such as a cooler for an exhaust gas recirculation system or a member for a fuel cell, which is required to have particularly excellent heat resistance and corrosion resistance. The present invention relates to a brazing composite material and a brazing product using the same.

[0002]

2. Description of the Related Art Conventionally, a stainless base clad material has been used as a brazing member constituting a heat exchanger such as an oil cooler for an automobile. This is one in which one or both sides of a stainless steel plate that is the base material is clad with copper as a brazing material, and the brazing material at the joint of the members is heated above its melting point and welded to braze the base materials together. It is designed to be combined with each other.

As a brazing material for members made of stainless steel, Ni-based or Co-based alloys, various Ni brazing materials having excellent corrosion resistance at joints are specified by the JIS standard. Further, as this Ni brazing material, powdered Ni is used.
A powdered Ni brazing material obtained by adding 4 to 22% by weight of a metal powder selected from Ni, Cr, or a Ni—Cr alloy to the brazing material has also been proposed (JP 2000-107A).
883 publication).

A so-called brazing composite material having a brazing layer made of Ni, Ti, or the like on the surface of stainless steel as a base material has also been proposed, as in the case of the above-mentioned stainless steel-based clad material (Japanese Patent Laid-Open No. Hei 10 (1999) -31977). 7-299592).

[0005]

By the way, these conventional brazing materials or composite materials for brazing are directly exposed to a high temperature and highly corrosive gas or liquid such as a heat exchanger, for example, an exhaust gas recirculation device (hereinafter referred to as "exhaust gas recirculation device"). EGR (Exhaust Gas Recirculat
It has been found that the following problems occur when it is used for the production of a cooler for a fuel cell (referred to as ion) or a cooler for reforming a fuel cell.

That is, first, since extremely high-temperature gas and highly corrosive exhaust gas flow inside the EGR cooler and the fuel cell reforming cooler, the above-mentioned stainless steel-based clad material is used as a material for the EGR cooler and the like. If it is used, sufficient heat resistance and corrosion resistance cannot be exhibited, so that there arises a problem that the brazing material melts or corrodes during use and the joint strength is significantly reduced.

On the other hand, various Ni as shown in JIS standards
Although the brazing material can exhibit excellent heat resistance and corrosion resistance as compared with the above-mentioned stainless steel-based clad material, since its form is powdery, it is necessary to apply it to each joint at the time of use. Is coming. However, since this brazing work requires a great deal of labor and time, there is a problem that the productivity of brazed products is remarkably reduced, resulting in an increase in manufacturing cost.

Further, in the conventional brazing composite material, since the flowability of the brazing layer is not good as described later, when it is applied to a brazing member having a complicated brazing portion shape. However, there is a problem that a good joint surface and a sufficient joint strength cannot be obtained, and the reliability of the joint is lowered.

Further, N is formed on the surface of the base material such as stainless steel.
If a brazing material such as i or Ti is directly joined, a brittle layer made of a new intermetallic compound or the like is formed between the brazing material and the base material due to the heat when brazing is performed. May be significantly reduced. Further, depending on the reaction mode, a phenomenon called so-called SUS erosion may occur in which the base material component is locally dissolved in the brazing material and the base material is locally eroded.

Therefore, the present invention has been devised to solve the above problems, and its purpose is not only to exhibit excellent heat resistance and corrosion resistance but also to have good brazing workability and bonding strength. (EN) Provided are a novel composite brazing material, a brazing composite material and a brazing product which are excellent in

[0011]

In order to achieve the above object, a first aspect of the present invention provides a nickel layer made of nickel or a nickel alloy, titanium, and titanium.
It is a composite brazing material comprising a laminated body in which one layer or two or more non-nickel layers made of manganese, tin, zinc, aluminum, copper or alloys thereof are laminated.

That is, since a conventional nickel metal simple substance has a high melting point of about 1450 ° C., it is difficult to use it as a brazing filler metal for joining stainless steel or the like as it is. However, it is possible to lower the melting point by mixing non-nickel metal such as titanium, manganese, tin, zinc, aluminum, copper or alloys thereof with nickel, for example, 1200
The inventors of the present invention have found that brazing can be performed in the vicinity of ° C and have reached the present invention. And, in the composite brazing material of the present invention, it is possible to maintain excellent bonding strength over a long period of time because it can exhibit excellent heat resistance and corrosion resistance as compared with the conventional brazing material of simple copper alone, and of course, to nickel simple substance. In comparison, the flowability of the brazing filler metal is good, and handling is easier than in the powder form, so that the brazing workability can be greatly improved.

When the nickel layer further contains 0.02 to 10% by weight of phosphorus, it is possible to remarkably improve the flowability and wettability of the molten metal.

A second invention is for brazing, characterized in that, as described in claims 6 and 7, the above-mentioned composite brazing material is joined to the surface of a substrate through a resin made of an organic material. Since it is a composite material, it can exhibit excellent heat resistance and corrosion resistance as compared with the conventional copper brazing composite material, and also has significantly improved melt flowability as compared to the nickel simple brazing composite material. It can demonstrate excellent brazing workability.

In addition, the above-mentioned composite brazing material is not directly bonded to the surface of the base material as in the conventional case, but is bonded via a resin such as methylcellulose, so that an intermetallic compound may be formed at the interface between the two during brazing. It is possible to effectively suppress the occurrence of adverse effects such as the formation of a brittle layer to lower the bonding strength and the SUS erosion. Therefore,
As described in claims 8 and 9, it is possible to use an alloy containing iron as a main component or stainless steel as it is as a base material, and suppress an increase in the cost of the entire brazing composite material. be able to.

And as described in claims 10 and 11,
By using the above new composite brazing material or composite material for brazing, it is possible to efficiently provide a highly reliable brazing product having excellent heat resistance and corrosion resistance at low cost. Become.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

First, FIG. 1 shows an embodiment of a composite brazing material 1 according to the present invention.

As shown in the figure, this composite brazing material 1 comprises a nickel layer 2 made of nickel or a nickel alloy,
The non-nickel metal, that is, a non-nickel layer 3 made of titanium, manganese, tin, zinc, aluminum, copper, or an alloy thereof is stacked to form a plate-shaped laminate.

Here, this laminated body has a thickness of, for example, 0. A few meters
A strip of nickel or a nickel alloy having a strip shape of m and a non-nickel metal of the same strip are superposed and repeatedly rolled to obtain a desired thickness easily. The lamination ratio (thickness) of the nickel layer 2 and the non-nickel layer 3 is not particularly limited, and the desired melting point temperature (brazing temperature and heat resistant temperature) can be obtained by arbitrarily changing the ratio. be able to. That is, the nickel layer 2
The melting point of the nickel or nickel alloy forming the alloy is titanium, manganese, tin, zinc, which forms the non-nickel layer 3.
Since it is higher than that of aluminum, copper or their alloys, generally, when the lamination ratio of the nickel layer 2 is increased, the melting point becomes high, and conversely, when the lamination ratio of the non-nickel layer 3 is increased, the melting point can be lowered. For example, when the ratio of the nickel layer 2 to the non-nickel layer 3 is about 1: 1 in such a form, the melting point temperature decreases to about 1200 ° C.,
The heat resistance and brazing temperature (melt flow) in the vicinity can be exhibited.

Then, a brazing filler metal for producing a heat exchanger, for example, an EGR cooler or a fuel cell reforming cooler, in which the composite brazing filler metal 1 of the present invention is exposed to the above-mentioned high temperature and highly corrosive gas or liquid. Since it can exhibit excellent heat resistance and corrosion resistance, it can maintain excellent bond strength over a long period of time, and has better molten metal flowability than the brazing filler metal containing nickel alone Since it is easier to handle, the workability of brazing can be greatly improved.

As another embodiment of the present invention, FIG.
As shown in FIG. 5, a nickel-plated layer 2 may be formed into a wire and the periphery thereof may be covered with a non-nickel layer 3 to form a laminated body having a circular cross section. In addition, phosphorus is added to the nickel layer 2 in an amount of 0.02 to 1
If it is contained in an amount of 0% by weight, or if it is combined with nickel-phosphorus plating to add 0.02 to 10% by weight of phosphorus, the flowability, wettability, oxidation resistance, etc. of the molten metal can be significantly improved. Will also be possible. Here, the phosphorus content is set to 0.
The content is limited to 02 to 10% by weight, if the content is less than 0.02% by weight, the flowability of the molten metal cannot be improved. On the contrary, if it exceeds 10% by weight, the brazing layer becomes brittle and the vibration fatigue characteristics and the bonding strength are remarkably increased. It is because it decreases, desirably 0.5 to 8% by weight
Is the range.

Further, as shown in FIGS. 3 and 4, the non-nickel layer 3 is further composed of two or more layers, for example, a titanium layer 3a made of titanium or a titanium alloy and a copper layer 3b made of copper or a copper alloy. The same effect can be obtained even if it is configured by the above.

Next, FIG. 5 shows an embodiment of the brazing composite material 4 according to the second invention.

As shown in the figure, the brazing composite material 4 is a composite material as described above on one side of a base material 5 which is a metal part constituting a brazing product such as a heat exchanger, for example, iron or stainless steel. The brazing material 1 is joined through a resin such as methyl cellulose.

As described above, since the composite brazing material 1 can exhibit excellent heat resistance and corrosion resistance, the brazing composite material 4 is heat-exchanged by exposing it to a gas or liquid of high temperature and high corrosiveness. When used as a dexterity member, excellent bond strength can be maintained for a long period of time. Moreover, by bonding the composite brazing material 1 to the base material 5 in advance, more excellent workability can be exhibited.

Also in this embodiment, the composite brazing material 1 may be bonded not only to one side but also to both sides as shown in FIG. 6 depending on the part to be used.
The same is true even if the shape is a rod shape or a complicated three-dimensional shape as shown in FIG. Further, as shown in FIG. 8, even if the composite brazing material 1 is formed of three or more layers, the same effect can be obtained.

[0028]

EXAMPLES Specific examples of the present invention will be described below together with comparative examples and conventional examples.

Example 1 First, a copper strip (thickness: 0.12 m)
m), titanium strips (thickness 0.20 mm) and nickel strips (thickness 0.15 mm) were clad and laminated by a rolling method, and then rolled repeatedly to produce a composite brazing material having a thickness of 70 μm. Next, this composite brazing material is applied to a thickness of 0.6 m.
It was installed on a stainless steel strip (SUS304) of m so that its nickel side was in contact, heated and melted in a tube furnace at 1200 ° C to form a composite, and then the characteristics of the composite material were evaluated.

As shown in Table 1 below, the evaluation method was performed from the viewpoints of the melt flowability (fillet formation state) of the brazing material, the presence or absence of corrosion, the SUS plate thickness residual rate, and the brazing productivity. It was Here, regarding the melt flowability, a SUS304 pipe was placed on the surface of each produced composite material, and
The fillet shape of the brazed part when brazing at 00 ° C was evaluated. In addition, the corrosiveness was evaluated by correlating the sample with 100 in a corrosive solution containing chloride ion, nitrate ion, and sulfate ion.
After immersing for 0 hour and taking out, the structure of the brazed portion was observed and examined for corrosion. Further SUS
The remaining plate thickness was measured by observing the cross section of the test piece.

(Example 2) Titanium strip (thickness: 0.20 m)
m) and nickel strips (thickness 0.15 mm) were clad by a rolling method, and rolling was repeated to obtain a total thickness of titanium and nickel of 70 μm. The composite material is brought into contact with the SUS substrate via methyl cellulose dissolved in alcohol, and then bonded by evaporating and drying the alcohol component, and then heated in a tube furnace at 1200 ° C. to form a composite, The characteristics were evaluated by the same method as in Example 1.

(Example 3) Manganese alloy (thickness 0.2)
0 mm) and nickel strips (thickness 0.10 mm) were used to form a composite material in the same manner as in Example 2, and the characteristics thereof were evaluated by the same method as in Example 1.

(Comparative Example 1) 304 SUS (thickness: 2.5
(mm) surface is directly clad with a nickel strip (thickness 0.15 mm) by a rolling method, the rolling is repeated until the thickness of nickel is 70 μm, and this is heated in a tube furnace at 1200 ° C. Evaluation was performed in the same manner as in Example 1.

(Comparative Example 2) 304 SUS (thickness: 2.5
mm), titanium strips (thickness 0.20 mm) and nickel strips (thickness 0.15 mm) were combined by rolling so that the total thickness of titanium and nickel became 70 μm. The composite material was formed by various methods, and its characteristics were evaluated in the same manner as in Example 1.

Comparative Example 3 Manganese alloy strip (thickness: 0.
A composite material was formed by the same method as in Comparative Example 2 except that 1.0 mm) and a nickel strip (thickness: 0.20 mm) were used, and the characteristics thereof were evaluated in the same manner as in Example 1.

(Conventional Example 1) A similar composite material was formed except that a copper strip was used in place of the nickel strip of Comparative Example 1, and the characteristics thereof were evaluated in the same manner as in Example 1.

(Conventional Example 2) A commercially available powdered Ni brazing material dissolved in a synthetic resin binder was applied to one side of a SUS304 strip to form a brazing layer, which was then heated at 1200 ° C. in a vacuum furnace.
The wax layer was heated to 100 ° C. for melting and the properties thereof were evaluated in the same manner as in Example 1.

[0038]

[Table 1]

As a result, as is clear from Table 1, all of Examples 1 to 3 according to the present invention can be brazed at 1200 ° C., and have any of braze flowability and brazing productivity. Was also excellent. In addition, almost no corrosion occurs, and the residual rate of any SUS plate greatly exceeds 90%,
Exhibited excellent corrosion resistance. In particular, it was found that in Examples 2 and 3 in which the base material and the brazing material were joined with resin, excellent results were obtained with respect to the flowability of the brazing filler metal and the residual rate of the SUS plate.

On the other hand, in Comparative Example 1 using nickel alone as the brazing material, it did not melt at the brazing temperature of 1200 ° C. and did not function as a brazing material. Further, in Comparative Examples 2 and 3 in which the brazing material was directly joined to SUS, the brazing filler metal flowability, brazing productivity, etc. were relatively good, but the residual rate of the SUS plate was found in Example 1 ~ 3
Significantly lower than that of, and practical application is difficult.

On the other hand, Conventional Example 1, which has been conventionally used as a heat exchanger for automobile oil coolers and the like, is good in terms of wax flowability, brazing productivity, and SUS plate survival rate. Corrosion occurred and the corrosion resistance was poor. In addition, the conventional example 2 using the powdery brazing material,
Although it was good in terms of the flowability of the brazing filler metal and the residual rate of the SUS plate, the brazing productivity was significantly inferior to any of the above examples.

[0042]

In summary, according to the present invention, excellent heat resistance and corrosion resistance can be exhibited as compared with conventional brazing filler metals such as copper, so that excellent bond strength can be maintained for a long period of time, and nickel alone can be used. In comparison, the flowability of the molten metal is good, and the handling is easier than that of the powdery one, so that the brazing workability is greatly improved.

Further, since the base material and the brazing filler metal are not directly joined to each other, it is possible to surely avoid inconveniences such as generation of brittle layers such as intermetallic compounds at the interface and so-called SUS erosion. it can.

As a result, the production efficiency of the brazed product is improved, the manufacturing cost can be reduced, and a highly reliable brazed product of high quality can be obtained. Exert.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing an embodiment of a composite brazing material according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing another embodiment of the composite brazing material according to the present invention, which is formed into a wire shape.

FIG. 3 is an enlarged cross-sectional view showing another embodiment of the composite brazing material according to the present invention, showing a state in which two non-nickel layers are laminated on a nickel layer.

FIG. 4 is an enlarged cross-sectional view showing another embodiment of the composite brazing material according to the present invention, showing a state in which two non-nickel layers are laminated on a wire-shaped nickel layer.

FIG. 5 is an enlarged sectional view showing an embodiment of a brazing composite material according to the present invention.

FIG. 6 is an enlarged cross-sectional view showing another embodiment of a brazing composite material according to the present invention, in which the composite brazing material is joined to both surfaces of a base material through a resin.

FIG. 7 is an enlarged cross-sectional view showing another embodiment of a brazing composite material according to the present invention, in which the composite brazing material is joined to the surface of a wire-shaped base material through a resin. is there.

FIG. 8 is an enlarged cross-sectional view showing another embodiment of the brazing composite material according to the present invention, showing a state in which a composite brazing material in which two non-nickel layers are laminated on a nickel layer is laminated. It is a thing.

FIG. 9 is an enlarged cross-sectional view showing another embodiment of a brazing composite material according to the present invention, which is a composite in which two non-nickel layers are laminated on a nickel layer on the surface of a wire-shaped substrate. It shows a state in which a brazing material is laminated.

[Explanation of symbols]

1 Composite brazing material 2 Nickel layer 3 Non-nickel layer 4 Composite material for brazing 5 base materials 6 resin

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C22C 22/00 C22C 22/00 38/00 302 38/00 302Z (72) Inventor Masayoshi Aoyama Chiyoda-ku, Tokyo 1-6-1 Otemachi Nitrate Cable Co., Ltd. (72) Inventor Shikaku Shirai 1-6-1 Otemachi 1-6 Otemachi, Chiyoda-ku, Tokyo

Claims (11)

[Claims] 1. A composite comprising a nickel layer made of nickel or a nickel alloy and a non-nickel layer made of titanium, manganese, tin, zinc, aluminum, copper, or an alloy thereof, which are stacked on each other. Brazing material. 2. The composite brazing material according to claim 1, wherein the non-nickel layer is formed by laminating a copper layer made of copper or a copper alloy and a titanium layer made of titanium or a titanium alloy. 3. A composite brazing material comprising a laminated body in which a nickel layer made of nickel or a nickel alloy and a titanium layer made of titanium or a titanium alloy are superposed. 4. A composite brazing material comprising a laminated body in which a nickel layer made of nickel or a nickel alloy and a manganese layer made of manganese or a manganese alloy are laminated. 5. Phosphorus in the nickel layer is 0.02-1.
The composite brazing material according to any one of claims 1 to 4, wherein the composite brazing material contains 0% by weight. 6. A composite material for brazing, wherein the composite brazing material according to any one of claims 1 to 5 is bonded to the surface of a base material via a resin. 7. The brazing composite material according to claim 6, wherein the resin is made of an organic material. 8. The brazing composite material according to claim 6, wherein the base material is an alloy containing iron as a main component. 9. The brazing composite material according to claim 6, wherein the base material is stainless steel. 10. A brazed product assembled by using the composite brazing material according to any one of claims 1 to 5. 11. A brazed product assembled by the brazing composite material according to any one of claims 6 to 10.