JPH0371956A - Manufacture of alloy fine wire - Google Patents

Abstract

PURPOSE:To stably manufacture a continuous alloy fine wire by forming cooling liquid layer having outer layer and inner layer with centrifugal force in a rotating cylindrical drum, injecting molten Ti-Ni series alloy as jet stream into this liquid layer and solidifying the molten metal. CONSTITUTION:On inner wall face of the cylindrical drum 1, the liquid multiple layers 5 are formed with the centrifugal force by rotating the drum. A crucible 6 for melting the alloy in the drum 1 is arranged as hanging downward from the center. The molten metal jet stream 8 of Ti-Ni series alloy is injected into the liquid layer 5 in the drum from an injection nozzle 7 for spinning molten wire at tip part of the crucible. The liquid multiple layers of water in the outside layer 5a and silicone in the inside layer 5b on the wall face of drum, are formed with the centrifugal force of drum rotation. By this method, the stable continuous alloy fine wire can be manufactured.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to TiNi used for spring materials and actuators.
The present invention relates to a method for manufacturing thin alloy wires such as shape memory alloy thin wires.

[Prior Art] Generally, TiNi alloys are currently produced mainly by drawing through a die.

It is well known that TiNi alloy has poor workability, and it is usually made into a diameter of 5 to 10 m by hot working after melting and casting.
m, and then processed into predetermined dimensions by cold working (dice drawing method). Here, the TiNi alloy wire is
Due to severe work hardening, repeated annealing is required. Therefore, there is a problem in that the cost required for cold working accounts for most of the cost of the TiNi alloy wire. Recent research has
In order to solve the problems of the die drawing method, a liquid layer is formed in a rotating cylindrical drum by centrifugal force, and molten metal is injected as a jet into the liquid layer and solidified to produce fine metal wire. has been proposed (Japanese Unexamined Patent Publication No. 55-
84948).

With the above method, a thin metal wire with a circular cross section can be easily obtained. However, according to this method, since water is used as a cooling medium, the oxidation reactivity due to water differs depending on the type of alloy composition. In particular, alloys containing Ti, such as alloys with strong oxidation reactivity such as TiNi, However, the resulting wire sometimes broke due to oxidation in the coolant.

Therefore, research is currently underway on a method of using silicone oil that does not contain any water to prevent oxidation in the coolant.

[Problem to be solved by the invention] Silicone oil is extremely effective in preventing oxidation on the surface of thin alloy wires, but it has extremely low specific heat and thermal conductivity, and the solidification and cooling speed of thin alloy wires is slow, so silicone oil cannot melt. The jet remains molten even after entering the coolant, and eventually solidifies while floating in the coolant. In such cases, other problems arise, such as irregular and disordered solidification, resulting in thin wires breaking during solidification, and the reality is that continuous thin wires have not yet been obtained. be.

Therefore, a technical object of the present invention is to provide a method for manufacturing a stable continuous thin wire of TiNi alloy.

[Means for Solving the Problems] According to the present invention, a cooling liquid layer is formed in a rotating cylindrical drum by centrifugal force, and Ti is added to the cooling liquid layer in the cooling liquid layer.
A method for producing a thin TiNi alloy wire, in which a molten Ni alloy is injected as a jet and the molten metal is solidified, the method comprising: the cooling liquid layer having an outer layer and an inner layer. is obtained.

According to the present invention, in the method for producing a thin TiNi alloy wire, the liquid in the outer layer includes at least one of ethyl alcohol, ethylene gelcol, and silicone oil;
A method for manufacturing a TiNi-based alloy thin wire is obtained, characterized in that water is used in the inner layer.

[Example] The present invention will be explained in detail below.

FIG. 1(a) is a diagram showing an apparatus for producing a thin alloy wire according to an embodiment of the present invention.

In FIG. 1(a), the manufacturing apparatus includes a cylindrical drum 1 whose negative side is open, a rotating shaft 2 having one end at the center of the other surface of the cylindrical drum 1, and a rotating shaft 2 that rotatably supports this shaft. It has sliding bearings 3, 3.

Further, an outflow prevention plate 4 having a surface protruding in the direction of the central axis is provided on the edge of the drum 1, and a liquid multilayer 5 is formed on the inner wall surface of the drum by the centrifugal force caused by the rotation of the drum. has been done.

On the other hand, within this drum 1, a crucible 6 for melting the alloy is arranged extending downward from the center. A jet nozzle 7 for melt spinning is provided at the tip of the crucible, from which a molten metal jet 8 is jetted onto the liquid layer 5 of the drum. Further, in this crucible 6, a molten metal 9 of the alloy is generated by a heating coil.

The other end of the rotating shaft 2 of this drum is connected to and driven by a motor 10.

The crucible 6 is supported by support members 11a, llb, llc, and 11d so that its position can be adjusted in the vertical and horizontal directions.

Furthermore, an Ar gas introduction pipe 12 that serves as a pressure source for injecting the molten alloy is provided at the upper part of the crucible 6.

FIG. 1(b) is a partially enlarged sectional view of the drum 1 shown in FIG. 1(a).

In FIG. 1(b), a liquid multilayer of water is formed on the outer layer 5a on the drum wall surface and silicone is formed on the inner layer 5b by the centrifugal force of the rotation of the drum.

Example 1 Using an apparatus using a refrigerant at a temperature of 0° C. and having an inner diameter of 500 mm and a liquid layer of 20 mm in depth as the drum 1 shown in FIG. The molten metal is melted at a temperature 50° C. higher than the melting point, and the argon gas pressure introduced into the crucible 6 through the argon gas introduction pipe 12 is controlled, and the molten metal is passed through a spinning nozzle with a hole diameter of D (μm) at a speed of 430 mm/min. It ejected into the liquid layer 5. At this time, silicone oil was used as the liquid layer inside the drum 1, and water was used as the liquid layer outside the drum 1. The speed of the drum at this time was 500 mm/min.

For comparison, spinning was carried out as above with a different liquid layer (Comparative Example 1.2). On the other hand, an alloy with a similar composition was manufactured by the conventional die drawing method (Comparative Example 3).
.

The alloy composition used here was investigated for its fine line formation properties.
Furthermore, the produced thin wires were heat treated at 800° C. for 2 hours, and the martensitic transformation temperature (M s ) of each sample was measured using a differential scanning calorimeter (D SC). The measurement results are shown in Table 1.

Furthermore, the results of the investigation regarding the gas analysis values are also listed.

From Table 1, in Example 1 and Comparative Examples 1 and 2.3, when silicone oil and water are used as the refrigerant, by making the refrigerant layer a double layer containing water, the alloy fineness is significantly reduced. changes for the better. In other words, it was found that although no fine lines were obtained with water, some degree of fine lines (short lines of about 50 mm) were obtained using silicone oil with an extremely low water content.

However, it is difficult to say that it is a thin alloy wire, and a thin alloy wire was obtained by forming a double layer of refrigerant using the buffalo silicone oil of Example 1. This means that the cooling medium plays a relatively large role in improving the ability to form fine lines.

This can be clearly determined in gas analysis.

The mechanical properties of alloys with strong oxidation reactivity such as TiNi alloys deteriorate significantly due to oxidation of the surface of the alloy thin wires.

As shown in Table 1, water has the highest oxygen level, followed by Comparative Example 1. Example 1. It is clearly seen that the oxygen level decreases in the order of Comparative Example 3, and the fine wire properties of the alloy follow it.

Now, one of the most important properties of shape memory properties, Ms.
Regarding this point, by using the invented multilayer refrigerant, values equivalent to those of the conventional method were obtained.

As described above, by the method of the present invention, it is possible to produce a TiNi-based shape memory alloy thin wire with good thin wire formability (including continuity).

[Effects of the Invention] As explained above, according to the present invention, it is possible to provide a method for manufacturing a thin alloy wire that can produce a stable continuous thin alloy wire.

Figure 1 (α)

[Brief explanation of drawings]

FIG. 1(a) is a diagram showing an apparatus for producing a thin alloy wire according to an embodiment of the present invention, and FIG. 1(b) is a partially enlarged sectional view of the drum 1 of the apparatus for producing a thin alloy wire in FIG. 1(a). It is. In the figure, 1... cylindrical drum, 2... rotating shaft, 3...
・Sliding bearing, 4... Outflow prevention plate, 5... Liquid layer, 5a... Water, 5b is silicone oil, 6... Crucible, 7... Spray nozzle, 8... Molten metal jet, 9・
...Alloy molten metal, 10--Motor lla, llb, l
ie, 1ld--support member. Figure 1 (b) Procedural amendment (voluntary) Date 70327, 1995

Claims (1)

[Claims] 1. A cooling liquid layer is formed in a rotating cylindrical drum by centrifugal force, and a molten TiNi alloy is injected as a jet into the cooling liquid layer to solidify the molten metal. 1. A method for producing a thin TiNi alloy wire, wherein the cooling liquid layer has an outer layer and an inner layer. 2. The method for producing a thin TiNi alloy wire according to claim 1, wherein at least one of ethyl alcohol, ethylene glycol, and silicone oil is used for the outer layer, and water is used for the inner layer. manufacturing method.