JPS62161443A - Casting method for fine metallic wire - Google Patents

Abstract

PURPOSE:To prevent nozzle clogging and to obtain a large quantity of fine metallic fibers by feeding a heated gas to nozzle apertures to which a molten metal is supplied thereby heating the nozzle apertures. CONSTITUTION:A metal to be melted is housed into a melting crucible 2 and after the metal is melted by heating, the molten metal is ejected from the nozzle apertures 71-7n onto the surface of a cooling roll 1 under rotation so that the molten metal is quickly cooled to solidify. The gas heated by a heater 3 is injected from a heated gas injection nozzle 4 toward the nozzle apertures 71-7n to heat the nozzle apertures 71-7n. The nozzle clogging is thereby prevented and a large quantity of the metallic fibers finer than heretofore are obtd.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a method of jetting and colliding molten metal (including alloys, hereinafter simply referred to as molten metal) into the surface of a moving cooling substrate or into a solution through a nozzle hole with a small diameter. , relates to a method for directly producing thin metal wires by rapid solidification.

(Prior Art) The following are basic methods for directly producing thin metal wires by rapidly cooling molten metal.

In other words, the first category is centrifugal quenching method, single roll method,
The molten metal is jetted and impinged on the inner or outer circumferential surface of a solid cooling body, such as a rotating metal circular drum or roll, through narrow nozzle holes, and is rapidly cooled and solidified. In this case, the shape of the line created is flat in cross section. In addition, a semicircular groove is provided along the outer circumferential surface of the roll, and molten metal is spouted into the groove through a nozzle with multiple openings arranged in the direction of roll movement, and when overlapped, the cross section becomes elliptical. A line approaching the circle is obtained (see Japanese Patent Application Laid-open No. 121049/1983).

The second category is a method called rotating liquid spinning method.
As described in Japanese Unexamined Patent Publication No. 57-52550, molten metal is poured into a fluid stuck to the inside of a drum by centrifugal force and rapidly solidified.

According to this method, a line that is close to a perfect circle can be obtained.

In both categories, the cooling rate is extremely fast, so if the alloy composition is appropriately selected, an amorphous metal wire can be obtained.

The width or diameter of the cast wire is generally controlled by the width or diameter of the nozzle. When creating thin lines, a nozzle with a narrow opening is used. However, it is not possible to produce a metal wire with an arbitrarily small diameter using the liquid quenching method described above. If the diameter of the nozzle opening is made too small, nozzle clogging is likely to occur, making continuous casting for a long time difficult.

For example, Fe7bCr8B, 204 alloy has a melting point of 'rrn
(1110°C) to 9150°C, the lower limit of the diameter of the opening that allows continuous casting in the atmosphere at room temperature for 30 seconds or more without clogging the nozzle was about 0.4 mmφ. That is, as the opening became narrower to 0.3 φ and 0.2 φ, the time until nozzle blockage became shorter. In this case, the nozzle blockage is thought to be caused by solidification of the molten metal due to a drop in nozzle temperature due to the cold airflow generated by the cooling substrate, formation of reaction products between the molten metal and the nozzle material, or oxidation. In any case, when mass producing thin metal fibers,
Nozzle blockage was a major issue that needed to be solved.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems by continuously manufacturing thin metal wires (including fibers, hereinafter simply referred to as thin metal wires) with a small diameter. The purpose is to provide a method for casting.

(Means for Solving the Problems) The present invention is a method for casting molten metal (alloy) into a cooling substrate or solution through a narrow nozzle opening, rapidly solidifying it, and casting fine metal wire, which enables long-time casting. In order to prevent this, heated gas is sent from outside the nozzle opening during casting to prevent the nozzle from closing.

The present invention will be explained below with reference to the drawings. In FIG. 1, 1 is a rotating cooling roll, and 2 is a nozzle opening 7 on the surface facing the cooling roll 1 at the tip, as shown in FIGS. 2 and 3. 7. A melting crucible with one or more rows of 1, 4 is a nozzle opening 7°... 7 is a heated gas injection nozzle to send heated gas to the nozzle opening 7° and prevent the opening from clogging. A heating device 3 is provided on the outer surface. 5 is the nozzle 4
6 is a cast metal thin wire (fiber).

Melting crucible 2 for casting fine metal wire by the method of the present invention
After the metal (alloy) to be melted is accommodated and heated and melted, a nozzle opening 7 is formed on the surface of the rotating cooling roll 10. ... 7n, the molten metal is jetted out and rapidly solidified.

At this time, in the present invention, gas heated by the heating device 3 is injected from the heated gas injection nozzle 4 toward the nozzle opening to heat the opening and prevent clogging. The temperature of the supplied gas is Tm-, where the melting point of the molten metal is Tm-
It is necessary that the value be higher than 500 (g). Preferably, it is higher than Tm-300 (6). There is no particular upper limit to the temperature of the gas, but if it is too high, the nozzle part may be damaged, oxidation of the molten metal or nozzle material, and reaction between the molten metal and the nozzle may be promoted, so it is not preferable.

Generally, it is recommended to keep the temperature below the temperature of the molten metal.

The type of gas blown into the nozzle opening may be air or an inert gas (Ar + He t N2, etc.). If oxidation is particularly disliked, it is preferable to use an inert gas.

As a method of heating the gas, in the present invention, a method is used in which the gas is sent to a heat-resistant metal mother plate in which a heating element is spirally wound, but other methods may be used as long as the temperature conditions are satisfied.

It has been effective to place the positioner for supplying the heated gas on the upstream side of the nozzle with respect to the direction in which the cooling body moves, as shown in FIG. The distance between the tip of the injection nozzle for supplying heated gas and the nozzle for ejecting molten metal depends on the structure of the molten metal supply nozzle, but is usually in the range of 10 to 100 mm.

The nozzle for supplying the molten metal can be either single-hole or multi-hole. Although the shape of the opening may be a circle, an ellipse, a rectangle, or an h-shift, a circle is usually used for ease of processing. It is possible to drill holes with a minimum diameter of about 0.1 rran.

When a single-hole nozzle or a multi-hole nozzle is arranged as shown in FIG. 2 with respect to the moving direction of the cooling body, fibers with a flat cross section can be obtained. According to the method described in JP-A-59-147753, flat short fibers are obtained by using a cooling roll having V-shaped grooves perpendicular to the direction of movement. In addition, a cooling roll having semicircular grooves in the circumferential direction is used, and porous nozzles are arranged in the direction of movement of the cooling body as shown in Figure 3, and molten metal is spouted into the grooves. Or a line close to a circle can be obtained.

(Example) Example 1 Using the apparatus shown in FIG. 1, chemical compositions Fe76Cr8B,
2C4(at'Ir) alloy 1.5 kll 13
Melt at 00°C and make 2 openings with a diameter of 0.3 M on the bottom.
The molten metal was spouted through a nozzle having a diameter of 600 mm onto a copper cooling roll to produce 20 metal fibers.

Here, the openings were arranged so that the molten metals did not overlap each other. The peripheral speed of the roll is 27 m/s1! e. Is the ejection pressure 0.4kl? /crrI2. During casting, Ar gas is sent at a flow rate of 151 per minute, and the gas heated to 800°C by a heating device containing a heating element in a spiral is sent to the injection nozzle 4.
It was sprayed through the nozzle opening at the bottom of the crucible.

The position of the gas injection nozzle tip is 30 on the upstream side of the nozzle opening.
rm (Position from molten metal spouting nozzle position>VCL,,
Ta. The total amount dissolved by this method was approximately 0.3 rr.
It was obtained as an amorphous fiber with a width of m.

In a comparative example, which was cast under the same conditions except for spraying heated gas, the nozzle was completely clogged about 20 seconds after the start of casting, and the obtained fiber was 1 oooy, a yield of about 7%. Ta. Thus, it is clear that by employing the method of the present invention, the product yield in fiber production is significantly improved.

Example 2 Cooling roll with grooves (made of prepared alloy, diameter 600 m,
Groove direction is perpendicular to the movement direction, groove spacing 10I, groove width, depth,
A master alloy having the same composition and weight as in Example 1 was passed through a nozzle having 25 (7) openings with a nozzle opening diameter of 0.2 rtsr. After dissolving, it spouted out and was rapidly cooled. During pavement construction, He gas was heated to about 900° C. using the heating device 3 used in Example 1, and was ejected at 151°C per minute through a nozzle 4 (located 20 degrees upstream from the molten metal injection nozzle). By this method, the total amount of melted alloy (1.5 mm) was obtained as amorphous short fibers approximately 0.21 mm wide and 10 mm long.

In a comparative example, which was cast under the same conditions without spraying heated gas, the nozzle was completely clogged approximately 15 seconds after the start of casting, and the fibers obtained were 301! The yield was approximately 2 cm.

Thus, it is clear that by employing the method of the present invention, the yield of short fiber production is significantly improved.

(Effects of the Invention) As explained above, by adopting the method of the present invention when casting metal fibers using a nozzle with a small opening diameter, nozzle clogging can be prevented, and as a result, it is possible to prevent the nozzle from clogging more than before. It has become possible to make multi-digit thin metal fibers.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an example of an apparatus for carrying out the method of the present invention, and Fig. 2 is a bottom view showing an example of a multi-hole nozzle provided on the bottom of a crucible used in the present invention, with arrows indicating the moving direction of the cooling roll. show. FIG. 3 is a bottom view showing an example of a nozzle for producing fibers having a circular or elliptical cross section. 1: Cooling jar, 2: Melting crucible, 3: Heating device, 4:
Heated gas injection nozzle, 5: gas source, 6: thin metal wire (fiber), 7. ...7n: Nozzle opening diagram 1

Claims (1)

[Claims] (1) When casting a thin metal (alloy) wire by ejecting the molten metal (alloy) into the surface of a cooling substrate or into the solution moving through a nozzle and rapidly solidifying the metal (alloy), during casting, A method for casting thin metal wire characterized by sending heated gas to a nozzle opening for supplying molten metal to heat the nozzle opening (2) Temperature T of gas sent to the nozzle opening
Casting of thin metal wire according to claim 1, characterized in that (°C) satisfies the condition T≧Tm-500 (°C) with respect to the melting point Tm (°C) of the molten metal (alloy) to be cast. Method (3) Temperature T (℃) of gas sent to the nozzle opening
The method for casting thin metal wire according to claim 1, characterized in that the method satisfies the condition T≧Tm-300 (°C) with respect to the melting point Tm (°C) of the molten metal (alloy) to be cast (4). ) The method for casting a fine metal wire according to claim 1, wherein the gas sent to the nozzle opening is air or an inert gas.