JPH0768386A - Ni-Ti alloy joining method - Google Patents

Abstract

(57) [Summary] [Structure] When joining a Ni-Ti alloy member and a dissimilar metal member, heat dissipating parts having good thermal conductivity are attached to both members near the joint surface, and a Ni-Ti alloy member is bonded between the joint surfaces. Alternatively, the contact portions of the Ni-Ti alloy member and the intermediate member and the dissimilar metal member and the intermediate member are rapidly heated to a temperature at which these contact portions melt while interposing the Ni-based alloy intermediate member, and at the same time, the contact portions are simultaneously heated. N is characterized in that both members of the contact portion are compression-processed in directions opposite to each other and the melt extruded to the outside of each contact portion is brought into contact with the heat dissipation portion to rapidly solidify.
A method for joining an i-Ti alloy. [Effect] Ni-T having shape memory effect and superelastic effect
The i-based alloy and other dissimilar metals can be joined with sufficient strength and reliability, which is a significant effect in practice.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an intermetallic compound N
The present invention relates to a method for joining an i-Ti-based alloy, in particular, a Ni-Ti-based alloy having a shape memory effect and a superelastic effect and a dissimilar metal (including alloys; the same applies hereinafter) with high strength.

[0002]

2. Description of the Related Art Shape memory alloys are alloys having extremely remarkable characteristics such as shape memory effect and superelasticity effect. The shape memory effect is a phenomenon in which what is deformed by an external force in the state of martensite undergoes a phase transformation into austenite by heating, and spontaneously returns to its original shape before deformation. In addition, the superelastic effect is a phenomenon in which even if the austenite state is greatly deformed to the yield zone by an external force, it simply returns to its original shape like rubber without heating by only unloading the external force. To tell.

As alloys having a shape memory effect, several dozen types of alloys such as copper alloys and gold cadmium alloys are known.
Among them, Ni-Ti alloys have the best shape memory properties and superelastic properties.

The Ni-Ti alloy applied products include the following. Those that use the shape memory effect include air conditioner outlets, rice cooker pressure regulating valves, pipe joints, hot water valves, etc., and those that use the superelastic effect, catheter guide wires, brassiere cup wires. , Eyeglass frames, antennas for mobile phones, etc.

One of the technologies that must be solved in the development of these products is a bonding technology between a Ni--Ti alloy and a dissimilar metal. Especially like eyeglass frames, temples, end pieces, lens rims made of different metal materials,
In application to a product in which many parts such as bridges are joined and integrated, a part of parts made of Ni-Ti alloy and a part of parts made of dissimilar metals are locally and It was desired to develop a welding technique for firmly joining.

[0006]

The Ni--Ti alloy is
Although it is an intermetallic compound and a unique alloy with ductility, its composition range is in the atomic ratio of about 1: 1 or a very narrow range in which a specific element is substituted in a minute amount, and this ratio deviates slightly. And suddenly becomes brittle. Therefore, Ni-Ti
If the alloys are based alloys, laser welding, T
Welding can be performed easily and with high strength by fusion welding methods such as IG welding and electron beam welding, or pressure welding methods such as butt welding and friction welding.

However, when the mating member is a dissimilar metal other than the alloy, Ni--
A brittle layer was formed, which was formed by the reaction between the Ti-based alloy and the dissimilar alloy, and was largely outside the above-mentioned composition range, and it was not possible to obtain a bonding strength that could withstand practical use. Further, even in brazing, a fragile layer formed by the reaction of the Ni-Ti alloy and the brazing filler metal component is formed at the joint interface, and this also makes it possible to obtain a joint strength that can withstand practical use. There wasn't.

Therefore, in the conventional joining technique, the means of welding was abandoned and it was necessary to rely on a mechanical joining method such as screwing or caulking . However, the mechanical joining method has drawbacks in that the joint portion becomes coarse and looseness occurs in repeated use, which is essential for superelastic applications.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and when joining a component made of a Ni--Ti alloy and a component made of a dissimilar metal, a joining interface between the two components is provided. By interposing an intermediate member made of a specific metal in the steel and rationally treating the brittle reaction phase generated during melting, both parts are locally strengthened without impairing the above-mentioned characteristics of the Ni-Ti alloy. Disclosed is a joining method of welding to.

That is, according to the joining method of the present invention, when joining a Ni-Ti alloy member and a dissimilar metal member, heat radiating portions having good thermal conductivity are attached to both members in the vicinity of the joining surface, and the joining surfaces of both members are joined. The Ni-Ti based alloy member and the intermediate member and the contact portions of the dissimilar metal member and the intermediate member are rapidly heated to a temperature at which these contact portions are melted by interposing an Ni or Ni-based alloy intermediate member between them and simultaneously contact each other. The parts are compressed in a direction in which both members of the contact part oppose each other, and the melt extruded to the outside of each contact part is brought into contact with the heat dissipation part to rapidly solidify.

Another bonding method of the present invention is Ni-Ti.
In joining the alloy member and the dissimilar metal member, after the Ni or Ni-based alloy intermediate member is previously joined to the joining surface of the dissimilar metal member, good heat is generated in the vicinity of the joining surface between the Ni—Ti alloy member and the intermediate member. Ni-Ti with conductive heat sink attached
The joining surfaces of the system alloy member and the intermediate member are brought into contact with each other, and this contact portion is rapidly heated to a temperature at which the contact portion melts, and at the same time, the contact portion is subjected to compression processing in a direction in which both members of the contact portion face each other. The melt extruded to the outside of the contact portion is brought into contact with the heat radiating portion to rapidly solidify.

In any of the above-mentioned methods, it is effective to cut off the extruded portion formed of the cast structure that is extruded to the outside of the contact portion and rapidly solidified, and then perform polishing finishing.

In the above case, the Ni-Ti alloy is 40-60 at% Ni-Ti alloy, or the 40-60 at% Ni- alloy.
Ni of Ti alloy or part of Ti is Fe, Cr, A
l, V, Pd, Ag, Mn, Co, Mg, Nb, Mo,
It is effective to use a shape memory alloy or a superelastic alloy made of a Ni-Ti alloy in which one or more of Cu and B are substituted in a total amount of 20 at% or less. If pure Ni or a Ni-based alloy containing 60 wt% or more of Ni is used as the intermediate member, the effect is great.

[0014]

As described above, according to the present invention, since the intermediate member is interposed at the joining interface between the Ni-Ti alloy member and the dissimilar metal member, the Ni-Ti alloy is not melted when the members are melt-pressed and joined. There is no concern that the Ni-Ti alloy and the dissimilar metal will directly melt to form a brittle layer by melting only with the intermediate member. Therefore, various alloy materials can be used as the dissimilar metal member and a high-strength joint can be obtained. There is an advantage.

The reason why the intermediate member is made of pure Ni or a Ni-based alloy containing 60 wt% or more of Ni is as follows.

The technique forming part of the invention, namely Ni-
When joining a Ti-based alloy member and another metal member that is a mating member, a heat radiating section made of a good heat conductive material is attached near these joining surfaces, and the joining surfaces of both members are brought into contact with each other, and the contact is made. Part is heated rapidly to a temperature at which the contact parts of both members melt, and at the same time, the contact parts are compressed in a direction in which the two parts of the contact parts face each other. Most of this melt, which is the main cause of the decrease in strength, is extruded to the outside of the joint and removed, and the slightly remaining melt is solidified and at the same time as the above-mentioned compression processing, a layered molten metal forging with a thickness of 20 μm or less is forged. In order to prevent the melt extruded to the outside of the joint due to the organization of the structure and the compression processing from reacting with the Ni—Ti alloy member in the vicinity of the joint to form a brittle diffusion phase, the melt is Touch the heat sink In the rapid solidification method, various metals and alloys were selected as the other metal member as the mating member, and an experiment was attempted. There was a significant difference in the bonding strength depending on the type of the mating member. The Ni-based alloy containing the above showed the highest strength. Furthermore Ni
Since the base alloy has excellent brazeability and weldability with many other general metal materials, it is an object of the present invention to provide N.
It has been known that, in high-strength joining of an i-Ti alloy member and a dissimilar metal member, the effect is great if the intermediate member made of the Ni-based alloy is sandwiched between these joining interfaces.

Further, as a means for preliminarily joining the above-mentioned intermediate member to the joining surface on the side of the dissimilar alloy member, the conventional welding method or brazing method can be used. A normal resistance welding machine can be used for heating the bonding interface.

[0018]

EXAMPLES The present invention will now be described with reference to examples.

Example 1 The following experiment was conducted with a resistance welding machine equipped with the compression device (4) shown in FIG. Ni-Ti
A superelastic alloy wire (1) having a wire diameter of φ2.6 mm and a length of 30 mm made of (51.0 at% Ni-remaining Ti) as a system alloy member and the composition shown in Table 1 and having the same dimensions with a wire diameter of φ2.6 mm. A dissimilar metal wire (2) having a length of 30 mm is used, and both are clamped by an air-cooling electrode (3) made of a copper chromium alloy as a heat radiating jig as shown in FIG. 87 wt% N as an intermediate member between the end face of the
Inserting a 0.6 mm thick chip made of i-13 wt% Cr,
With the pressure device (4) pressurized to 20 kg / mm ² , select the optimum current value between 1500 and 3000 A according to the difference in the physical properties of each metal, then heat by energizing for 1/20 seconds to join the outer peripheral portion. Polished.

Next, as another joining method of the present invention, instead of sandwiching the intermediate member, a 1.0 mm-thick chip made of the above-mentioned intermediate member on the end face of the dissimilar metal wire shown in Table 2 is brazed with JIS-BAg6 at a high frequency. After contacting, the outer peripheral portion was polished after bonding under the same conditions as above.

Subsequently, as a comparative joining method, in the combination of the dissimilar metal wires shown in Tables 1 and 2 and the above superelastic alloy wire, only the heat radiating jig which is a part of the present invention is used without using an intermediate member. After that, they were joined under the same conditions as above. Further, as a comparative joining method, the melt was extruded to the outside, and at the same time, the extruded melt was brought into contact with the extruded melt to perform rapid solidification.

The tensile strength of each of the joints obtained by the present invention and the comparative joining method was measured by an Instron tensile tester. The results are shown in Tables 1 and 2. 2 and 3 are photographs of the metallographic structure of the cross section of the joint portion according to the present invention, and FIGS. 4 and 5 are explanatory diagrams of the metallographic photographs. First, FIG. 2 shows 51.0 at% Ni-residual Ti alloy (12) and pure T.
It is a cross section of a joint interface with i (13). In this case, the intermediate member (15) and pure Ti (13) are directly joined as shown in FIG.
It can be seen that the Ni-Ti alloy (12) is joined to the intermediate member (15) through the molten metal forging structure (14). Also, FIG. 3 shows 5
1 is a cross section of a joint interface between a 1.0 at% Ni-residual Ti alloy (12) and nickel silver (18). In this case, as shown in FIG. 5, the nickel silver (18) is mixed with the intermediate member (15) and silver solder (JIS-BAg6).
It can be seen that the Ni-Ti alloy (12) has been previously joined via the (17) and the intermediate member (15) via the molten metal forging structure (14).

[0023]

[Table 1]

[0024]

[Table 2]

As can be seen from Tables 1 and 2, the joint obtained by the comparative joining method according to only part of the technique constituting the present invention is the joint obtained by the conventional comparative joining method by upset butt welding. Since the comparatively high strength is obtained, it is understood that the heat dissipation jig of the present invention has an effect of improving the strength of the joint portion. Further, it is apparent that the present invention using the intermediate member can obtain stable and high strength even if the kind of the dissimilar metal is changed.

(Example 2) As a Ni-Ti alloy (5
0.5at% Ni-49.1at% Ti-0.4at% Cr) made of superelastic alloy wire with wire diameter φ1.6mm and length 37mm. After bending this into a U shape, A spectacle bridge (5) shown in FIG. 6 was produced by performing a memory heat treatment for a period of time. Next, a pair of lens rims (6) and (6) made of pure Ti as different kinds of metals are prepared, and as a joining method of the present invention, this is joined at both ends 5 mm of the bridge (5) as shown in FIG. As shown in Fig. 8, after clamped on the heat dissipation jigs (7) and (7 '), a thickness of 1.0mm x width 1.2mm consisting of (80wt% Ni-remaining Cr) between both members.
While the intermediate member (8) having a length of 3 mm was sandwiched between them, while applying a load of 100 kg, a current of 1200 A was passed for 1/20 seconds to electrically heat and complete the welding. As a result, as shown in FIG. 9, the melt extruded from the contact portion between the superelastic alloy bridge (5) and the intermediate member (8) by heating and pressurizing contact with the heat radiating jigs (7) and (7 '). It was rapidly solidified (9) and a molten metal forging structure (10) was formed at the joint interface between the bridge (5) and the intermediate member (8). Further, the solidified melt on the outside of the joint was ground to form an eyeglass frame.

Next, as a comparative joining method, a bridge (5) and a lens rim (6) similar to the above are prepared, both members are set in the structure shown in FIG. 10, and joined by conventional spot welding to join the spectacle frame. It was created. A cross-sectional view of the joint at this time is shown in FIG. 11. A weld nugget (11) was formed in which the melted material of both members simply solidified at the joint interface.

Further, as a comparative joining method, a bridge and a lens rim similar to the above are prepared, and JIS-BPd ₄
A spectacle frame was produced by using conventional paradigm brazing and joining by conventional high-frequency brazing.

With respect to the spectacle frame obtained by each of the above-mentioned joining methods, a pair of rinse rims bridged by a bridge as shown in FIG.
When a repeated twisting test was performed up to the 1000th time, in which the bridge was twisted by rotating it to the left and right to an angle of 1000, the spectacle frame produced according to the present invention maintained its original shape without being deformed.

On the other hand, the spectacle frame produced by the comparative joining method could not be executed up to the 1000th time because the joining interface was broken by the second twisting and was broken.
The spectacle frame created by the comparative joining method is 1
At the 1st twist, the wax was broken at the root of the adhered bridge and we could not execute it up to the 1000th time.

[0031]

As described above, according to the present invention, it is possible to join a Ni-Ti alloy having a shape memory effect and a superelastic effect to another dissimilar metal with practically sufficient strength and reliability. Therefore, it is extremely useful for application of Ni-Ti alloys to eyeglass frames and the like.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a welding machine used in a first embodiment.

FIG. 2 is a photograph of a metal structure of a cross section of a joint portion according to the present invention of Example 1.

FIG. 3 is an explanatory view of the photograph of the metal structure.

FIG. 4 is a metallographic photograph of a cross section of a joint according to another embodiment of the present invention.

FIG. 5 is an explanatory view of the photograph of the metal structure.

FIG. 6 is a Ni-Ti alloy of Example 2 (50.5 at% Ni-
4 is a perspective view showing a bridge made of 49.1 at% Ti-0.4 at% Cr).

FIG. 7 is a front view showing a joint position between a bridge and a lens rim of the second embodiment.

FIG. 8 is a cross-sectional view of a joining portion showing a set state of the present invention according to a second embodiment.

FIG. 9 is a cross-sectional view showing a joint portion of the present invention according to a second embodiment.

FIG. 10 is a cross-sectional view showing a set state of the comparative joining method of Example 2.

FIG. 11 is a cross-sectional view showing a joint portion of a comparative joining method of Example 2.

FIG. 12 is an explanatory diagram showing a method of a repeated twist test of Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ni-Ti type alloy member 2 Dissimilar metal member 3 Heat dissipation jig 4 Compressor 5 Bridge composed of Ni-Ti superelastic alloy 6 Lens rim composed of pure Ti 7,7 'Heat dissipation jig 8 Intermediate member 9 Extruded and quenched Solidified melt 10 Melt forged structure 11 Weld nugget with melt solidified at the joint interface 12 Ni-Ti alloy (51.0 at% Ni-residual Ti) 13 Pure Ti 14 Molten forged structure 15 Intermediate member (Ni83 wt% -residual Cr) ) 16 polished surface 17 silver solder (JIS-BAg6) 18 nickel silver

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C22C 19/03 A B23K 103: 14 103: 18 C22K 1:00 (72) Inventor Satoru Masunaga Fukui Prefecture Fukui City No. 4 Imaichi Town No. 4 Masuna Gamenlo Park Co., Ltd. (72) Inventor Kazuo Murata No. 4 Imaichi Town Fukui City Fukui City No. 17 Masuna Gamenlo Park Co., Ltd.

Claims (8)

[Claims] 1. When joining a Ni—Ti based alloy member and a dissimilar metal member, a heat radiating portion having good thermal conductivity is attached to both members near the joint surface, and Ni or N is provided between the joint surfaces of both members.
The contact parts of the Ni-Ti alloy member and the intermediate member and the dissimilar metal member and the intermediate member are rapidly heated to a temperature at which these contact parts are melted by interposing the i-based alloy intermediate member, and at the same time, the contact parts are Ni-Ti alloy joining, characterized in that both members of the contact portion are compression-processed in directions opposite to each other and the melt extruded to the outside of each contact portion is brought into contact with the heat radiating portion to rapidly solidify. Method. 2. The method of joining Ni-Ti alloys according to claim 1, wherein after extruding the extruded portion made of a cast structure that is extruded to the outside of each contact portion and rapidly solidified, polishing finish is performed. 3. A Ni—Ti alloy containing 40 to 60 at% Ni—T.
i alloy, or Ni or part of Ti of the 40-60 at% Ni-Ti alloy is Fe, Cr, Al, V, Pd, Ag, M
Ni obtained by substituting one or more of n, Co, Mg, Nb, Mo, Cu, and B in a total amount of 20 at% or less.
The method for joining Ni-Ti alloys according to claim 1 or 2, which is a shape memory alloy or a superelastic alloy made of a -Ti alloy. 4. The method for joining a Ni—Ti alloy according to claim 1, wherein the intermediate member made of Ni or a Ni-based alloy is pure Ni or a Ni-based alloy containing 60 wt% or more of Ni. . 5. When joining a Ni—Ti alloy member and a dissimilar metal member, Ni is previously formed on the joint surface of the dissimilar metal member.
Alternatively, after joining the Ni-based alloy intermediate member, Ni-Ti
A heat-dissipating portion having good thermal conductivity is attached in the vicinity of the joint surface between the base alloy member and the intermediate member to bring the joint surfaces between the Ni—Ti alloy member and the intermediate member into contact with each other, and the contact portion is melted by the contact portion. Rapid heating to a temperature at which the contact portion is simultaneously compressed in a direction in which both members of the contact portion face each other, and the melt extruded to the outside of the contact portion is brought into contact with the heat radiating portion to rapidly solidify. A method for joining Ni-Ti alloys, comprising: 6. The method for joining a Ni—Ti based alloy according to claim 5, wherein the extruded portion formed of a cast structure that has been extruded to the outside of the contact portion and rapidly solidified is cut off and then polished. 7. A Ni—Ti alloy is 40 to 60 at% Ni—T.
i alloy, or Ni or part of Ti of the 40-60 at% Ni-Ti alloy is Fe, Cr, Al, V, Pd, Ag, M
Ni obtained by substituting one or more of n, Co, Mg, Nb, Mo, Cu, and B in a total amount of 20 at% or less.
The method of joining a Ni-Ti alloy according to claim 5 or 6, which is a shape memory alloy or a superelastic alloy made of a -Ti alloy. 8. The method for joining a Ni—Ti alloy according to claim 5, wherein the intermediate member made of Ni or a Ni-based alloy is pure Ni or a Ni-based alloy containing 60 wt% or more of Ni. .