JPS5942162A - Production of amorphous ribbon - Google Patents

Abstract

PURPOSE:To obtain stably an amorphous ribbon having good surface characteristics by increasing the ejection pressure of the molten metal to be ejected toward a cooling nozzle under high speed rotation with lapse of time. CONSTITUTION:The tip of a nozzle 4 is raised upper than a hole 10b and the hole 10b is closed with a shutter 10c. A raw material for an amorphous ribbon is inserted into the nozzle 4, and an inert gas is put through a passage 10a into an electric furnace 5 to maintain the circumference of the nozzle 4 at an inert gaseous atmosphere. The raw material is melted in a furnace 5 to make molten metal 1. On the other hand, a shutter 10c is opened and the tip of the nozzle 4 is brought near a cooling roll 3 under high speed rotation; at the same time, the molten metal 1 in the nozzle 4 is ejected by the inert gas fed 7 into the nozzle. The ejection pressure of the metal 1 is increased with lapse of time in this case. The metal 1 ejected onto the circumferential surface of the roll 3 is quickly cooled while the metal contacts with the surface of the roll 3 for a certain specified distance owing to the wetting property therewith, whereby an amorphous ribbon 2 is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a method for manufacturing an amorphous ribbon used to make an amorphous core or the like.

Amorphous ribbons are generally made by liquid quenching such as a single roll method (single roll method);
The molten metal of the raw material is spouted from the nozzle hole toward the surface of the cooling roll rotating at high speed under the pressure of an inert gas such as argon gas, and is rapidly cooled and solidified to form an amorphous ribbon. This is the way to obtain. However, in the conventional one-roll method, etc., it was not possible to obtain an amorphous 4tT ribbon with a good free surface (a gill that does not contact the cooling roll surface) at a low rate. In other words, there was no reliable method for obtaining an amorphous ribbon with a good free surface.

Although not directly related to this invention, the inventor has previously
We have researched the influence of manufacturing conditions on the shape of an amorphous ribbon7, and found that the shape of an amorphous ribbon depends on the amount of ejection when molten metal is ejected, assuming the shape of the nozzle hole is constant. It depends on three factors: pressure PB, roll rotation speed R, and distance T''l (nozzle-roll gap) Z between the nozzle and the cooling roll surface, and when these change, the thickness h and width of the amorphous ribbon change. In addition to this research, the inventor also conducted six studies on the influence of manufacturing conditions on tτ on the surface properties of amorphous ribbons.As a result, Among the above three factors (PRI RI Z ), the surface quality largely depends on the ejection pressure PE and the distance Z between the nozzle tip and the cooling roll surface. When examining the change in the ejection pressure PF, we found that ++rjt and the ejection pressure P.

It was found that there is always a tendency for the ratio to increase to 1!1 over time.

Based on these three results, the first person can use the single roll method etc. to roll an amorphous ribbon with molten metal (il).
The inventors reached the conclusion that if the ejection pressure of 1.1 was increased over time, an amorphous ribbon with good surface quality could be obtained at all times, and the present invention was completed.

That is, in this invention, molten metal is jetted from a nozzle toward a cooling roll rotating at high speed, and the molten metal 1.・When creating an amorphous ribbon by rapidly solidifying metal, the ejection pressure of the molten metal changes over time;
'I want to raise two? The gist of this paper is the manufacturing method of the amorphous ribbon. Please take note of the following instructions,
I will clarify.

Amorphous Galibon's 'Ij・'' (modal L[,
Molten layer 1 gold? This is the same as the conventional manufacturing method except that the spout 1 of Ti (the top of the mouth) rises over time. For example, it is carried out using an apparatus as shown in FIG.

Figure 1 shows the amorphous ribbon used in the single roll method. It is a construction item. As shown in the figure, this amorphous ribbon manufacturing apparatus (f) is a high-speed cooling roll that receives and cools the ejected molten metal 1 on its surface to produce a long amorphous ribbon 2. Above the cooling roll 3, a nozzle 4 such as a slit nozzle that spouts out the molten metal 1, and an electric furnace 5 that slides around the nozzle 4 and melts the raw material in the nozzle 4 are installed. ?Has been done.

Nozzle 4-: A nozzle made of quartz, etc. is used. The bases of four nozzles are inserted into the gauge bot 6, and are supported by the gauge bot 6 so as to be movable up and down.

A pipe 7 for feeding an inert gas such as argon gas into the nozzle 4 is connected to the upper end of the cage hot 6 . From here, inert gas is sent to blow out the molten metal 1 in the nozzle 4. The opposite end of Baigua's gauge bot 6 1111 is an inert gas injection port.

A strain gauge type pressure sensor (response: 2500 Hz) 8 is installed near the gauge pot 6 of the pipe 7. The electric furnace 5 is equipped with a heater 5a.
The openings at the top and bottom ends are 67'! Difference consisting of interest9,10
covered with. The lid 9 has a hole 9a for passing the nozzle 4 through it.
The lid 10 is provided with a passage d: and a passage 10a for passing argon gas for creating an atmosphere inside the electric furnace 5.

A hole 10 for bringing the tip of the nozzle 4 out from inside the electric furnace 5
F3 and a shutter 10c for opening and closing the hole 10b are provided, respectively. The shutter 10c is provided to prevent the cooling roll 3 from being heated by the electric furnace 5 before spouting the molten metal 1 from the nozzle 4. before,
The tip of the nozzle 4 is raised above the hole 10b using an air cylinder or the like, and the shutter 10c is closed. cooling roll 3
The separator 11 provided below is for forcibly separating the amorphous ribbon 2 that is in close contact with the surface of the cooling roll 3 (k'l) to prevent the amorphous ribbon 2 from being wrapped around. This separator 11 is the +! of the amorphous ribbon 2.
? a If the WS is 5 mm or more, it is necessary because there is a risk that the amorphous ribbon 2 will be stuck tightly to the cooling roll 3, but if the width Ws is less than 5 mm (11・-), the amorphous ribbon This is not necessary since the ribbon 2 is separated from the cooling roll 3 by centrifugal force.

Using this amorphous ribbon manufacturing apparatus, an amorphous ribbon is manufactured in the following manner. First, the tip of the nozzle 4 is raised above the hole 10b by air sillage or the like, and the hole 10b is closed with the shutter 10c. The raw material for the amorphous ribbon is inserted into the nozzle 4, and the inert gas is introduced into the electric furnace 5 through the passage 10a.
and keep the area around the nozzle 4 in an inert gas atmosphere.

Next, the raw materials are melted in an electric furnace 5 to produce a molten f and a pH of 1. Open the shutter 10c and the tip of the nozzle 4<
, ii4 is brought close to the cooling roll 3, and the cooling roll 3 is rotated at high speed i.! At the same time, the molten metal 1 in the nozzle 4 is jetted out using an inert gas. At this time, the time is good.
This method is used to increase the ejection pressure of the metal with the force, and this method will be described in detail later. Molten gold IZX spouted onto the circumferential surface of the cooling roll 3
1 is due to the wettability with the surface of the cooling roll 3.
- While contacting the distance d and JL, it is rapidly solidified and becomes an amorphous ribbon 2.

This means that an amorphous ribbon with good surface quality can be obtained by increasing the ejection pressure of the molten metal over time.
It was derived from the following experiment.

Experiments 1 and 2 were carried out using an apparatus for making an amorphous ribbon as shown in FIG.

However, an alloy with the composition Fe7eBxaS is used as the raw material, and the cross-sectional area Sn of the nozzle is 0.0.
A 23 m quartz slit nozzle and a metal roll of diameter 30 cm and material SUJ 2 were used as the cooling roll.

[Experiment 1] The temperature Tm of the molten metal was 1300°C, the distance Z between the nozzle tip and the roll surface was 0.15 mm (!: L, and amorphous ribbons were made with various combinations of ejection pressure pE and roll rotation speed R. Then, the surface roughness in the width direction (X direction) of the free surface of the obtained amorphous ribbon was measured. However, the distance between the nozzle tip and the roll surface was from room temperature to the temperature of the molten metal Tm. Thermal expansion Δ of the nozzle due to the temperature of
Considering l, it was set to Z+Δl at room temperature. This and the following description also apply to Experiment 2, which will be described later. Further, the ejection pressure PE was measured by applying gravity to a pen oscillograph through a pressure sensor and a gravitational strain meter, and the roll rotation speed R was measured using a diffuse reflection type tachometer. Furthermore, the surface roughness of the free surface of the amorphous ribbon was expressed as the ten-point average roughness specified in JIS B 0601.

FIG. 2 shows the relationship between surface roughness and ejection pressure PR, and FIG. 3 shows the relationship between surface roughness and rotation speed R. From Figure 2, it can be seen that when the ejection pressure PE is about 0.5 kg74m or higher, the surface roughness becomes significantly better, and from Figure 3,
It can be seen that the surface roughness hardly depends on the rotation speed R (there is no fixed relationship).

[Experiment 2] The temperature Tm of the molten metal was 1300°C, and the ejection pressure PK was approximately 0.
．． Amorphous ribbons were produced as described above using various combinations of distance Z and rotation speed R at 48 kg/cJ. Then, the width direction of the free surface of the obtained amorphous ribbon (
The surface roughness in the X direction) was measured.

FIG. 4 shows the relationship between surface roughness and distance MZ. From this figure,
It can be seen that when the distance Z is about 0.15 mm or less, the surface roughness is significantly improved.

From the actual i@1.2, it was found that the ribbon surface quality strongly depends on the ejection pressure 1) E and the distance Z, but almost does not depend on the rotation speed R.

Next, for four of the amorphous ribbons A to D of the amorphous ribbons produced in Experiment 1.2, fluctuations in the ejection pressure (inert gas pressure) Pg during production are shown in FIGS. 5 to 8. During manufacturing, the ejection pressure PE is kept roughly constant, but it may vary depending on the manufacturing conditions. Table 1 shows the manufacturing conditions and surface roughness of the amorphous ribbons A to D.

(Hereafter, extra white) 3C From FIGS. 5 to 8, amorphous ribbon B (FIG. 6).

D (Fig. 8), in the steady state of 1 yen, the ejection pressure PR increases by -F, and in the amorphous ribbons A and C, the ejection pressure I'EC is almost Ii. I can see that. For amorphous ribbon B, the pressure increase (ΔP) between the beginning and end of the steady state is 1.78 x 10-” kylcrd,
For amorphous ribbon D, the pressure increase value is 0.085 kg/c
It was A.

From Table 1 and Figures 5 to 8, when we examine the relationship between fluctuations in ejection pressure PE and the surface texture (surface roughness) of the amorphous ribbon's own surface, we find that the increase in ejection pressure PE during manufacturing The amorphous ribbon seen here has a good surface roughness of about 2.0 μmRz, whereas the amorphous ribbon with a nearly constant ejection pressure PE has a poor surface roughness of about 6.0 μmRz. You can see that Moreover, the increase in the ejection pressure PE is t'r
It can also be seen that it depends on the ejection pressure P and the distance z, and tends to become more pronounced as the ejection pressure PF increases and the distance Z decreases. For this reason, if at least one of increasing the ejection pressure PE or decreasing the distance pt1cz is performed, the ejection pressure PE will increase over time during the production of the J1゛ crystalline ribbon. However, it is concluded that the surface quality of the amorphous ribbon is improved.

Next, we will discuss the causal relationship between the increase in ejection pressure I)E and the surface texture. When molten metal is jetted onto the surface of the cooling roll, a puddle of molten metal is formed between the surface of the cooling roll and the tip of the nozzle. 'The molten metal is continuously pulled out in a ribbon shape from this molten metal, resulting in an amorphous ribbon. However, if the formation of the molten metal is incomplete, the molten metal becomes turbulent, resulting in an amorphous ribbon. It is generally known that the shape and surface quality of amorphous ribbons tend to deteriorate. On the other hand, when an amorphous ribbon with good surface quality is obtained, the ejection pressure PH increases over time because the nozzle hole is completely formed. It is thought that the flow velocity of the molten metal gradually slowed down, resulting in an increase in the ejection pressure due to Bernoulli's theorem. In other words, as the ejection pressure PE becomes higher or the distance 2 becomes shorter, the molten pool is reliably pressed between the nozzle tip ☆7M and the roll surface, and the molten pool is completely formed. .

As a result, the flow rate of the molten metal gradually slows down, and the ejection pressure PE increases as described above. Therefore, considering this in reverse, if the ejection pressure PE is increased as time passes, the molten pool will be reliably suppressed and an amorphous ribbon with good surface quality will be obtained. Become.

f・r (Methods for increasing the output PE over time are not limited to increasing the ejection pressure to a high pressure or shortening the distance Z as described above. These methods include:
This method is used when the ejection pressure PR is fixed almost constant, but the gas pressure of the inert gas that pushes out the molten metal is increased over time, and the ejection pressure is increased over time. It's okay.

The method for manufacturing an amorphous IJ bomb according to the present invention is as described above, and the ejection pressure of the molten metal (i) is increased with the passage of time. , a good amorphous ribbon with a 4'1-like surface can be obtained.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of example 1 of an amorphous ribbon used in the method of manufacturing an amorphous ribbon according to the present invention; Fig. 2 is a diagram showing the ejection pressure PE and surface 1'IX. Figure 3 is a graph showing the relationship between rotation speed R and surface roughness, Figure 4 is a graph showing the relationship between distance Z and surface roughness, and Figures 5 to 8 are graphs showing the relationship between distance Z and surface roughness. Figure d1 is a graph showing the fluctuations in ejection pressure pE when manufacturing amorphous ribbons A to D, respectively. ■... Molten metal 2... Amorphous repair/ 3...
Cooling Roll 4-Third Nozzle Patent Applicant Matsushita Electric Works Co., Ltd. Agent Patent Attorney Takehiko Matsuki Ribbon Thickness h (
mm) Fig. 2 Ribbon thickness h (mm) Fig. 3 0.1 sec
Time Figure 5 Figure 6

Claims (1)

[Claims] (1) When creating an amorphous ribbon by jetting molten metal (iq) from a nozzle toward a cooling roll that rotates at high speed and rapidly solidifying the molten metal, the jetting pressure of the molten metal (iq) causes the molten metal to melt over time. A method for producing an amorphous ribbon characterized by making it resistant to oxidation.