JPH07102434B2 - Amorphous alloy ribbon manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is a method for producing a wide-width amorphous alloy ribbon by a liquid quenching method. The present invention relates to a method for stable production.

[Conventional technology]

In recent years, an amorphous alloy ribbon has been produced directly from a molten metal (including an alloy; the same applies hereinafter) by a liquid quenching method such as a single roll method or a double roll method. In particular, in the case of producing a wide non-deteriorating alloy ribbon, the molten alloy is injected from a pouring nozzle having a slit-shaped opening slot onto a cooling roll that rotates at high speed, and rapidly solidified to continuously melt the ribbon. The single roll method for manufacturing is often used. In order to stably produce amorphous alloy ribbons with few defects by this single roll method, the tip shape of the pouring nozzle, the distance between the pouring nozzle and the cooling roll, the speed and surface properties of the cooling roll, etc. It is known that the management of the operating conditions of the is extremely important.

In JP-A-53-53525, regarding the tip shape of the pouring nozzle, the pouring slit width is 0.2 to 1 mm, and the thickness of the front lip (the lip on the side where the molten metal flows and the ribbon is manufactured) is slit. 1.5 to 3 times the width, and the thickness of the back lip (the lip opposite the front lip) to 1 of the slit width.
It is suggested that it is important to continuously control the distance between the pouring nozzle and the surface of the cooling roll to 0.1 to 1 times the slit width in the continuous production of the amorphous alloy ribbon. .

The reason for limiting the numerical value of the nozzle tip shape in this way is to set the pool (paddle) 12 of the molten metal in the outlet slit 6 of the outflow nozzle 4 as shown in FIG. Mechanical support and control between 13 and front lip 14 is important for continuous strip casting. In FIG. 2, 7 is a cooling roll, and 7a is its moving direction.

However, in the casting experiment by the single roll method, the present inventors did not find a situation in which the paddle was mechanically supported by the rear lip and the front lip even when stable continuous plate-making was performed. . Rather, excessive support of the paddle by the front lip interfered with stable plate making and sometimes resulted in nozzle failure.

Further, JP-A-56-56758 discloses the shape of the tip of the pouring nozzle in which the opening width of the pouring nozzle is 1.5 to 6 mm, and the gap between the pouring nozzle and the surface of the cooling roll is 0.005 to 0.6 of the slit width. I suggest doubling. However, the pouring nozzle having such a wide opening has a problem in stable plate making, and it is difficult to continue the operation for a long time.

Regarding the shape of the tip of the pouring nozzle, Japanese Utility Model Laid-Open No. 156-156257 strives to secure stable plate-making by providing a stepped retreat with a step of 0.3 mm or more on the bottom of the front lip 2 mm or more from the opening slit. . However, when an operation of continuously producing a wide amorphous alloy ribbon for a long time was carried out, it was found that such conditions alone were not sufficient to sustain stable plate production.

Furthermore, in International Publication W084 / 03852, the width of the slit is
0.2 to 1 mm, the thickness of the back lip is 3 mm or more and the thickness of the front lip is 3 to 10 mm, and the gap between the pouring nozzle lip and the surface of the cooling roll is wider at the back lip than at the front lip. is suggesting. However, with this method, stable plate-making cannot be continuously maintained.

Japanese Patent Application Laid-Open No. 61-159246 proposes a device for eliminating the mechanical support of the pool by making the thickness of the front lip 0.8 times or less the slit width. In this case, the thickness of the front lip suitable for manufacturing the amorphous alloy ribbon is a function of the slit width, but according to the knowledge of the present inventors, the appropriate thickness of the front lip is not a function of the slit width, Should be limited by absolute value.

[Problems to be Solved by the Invention]

As described above, some proposals have been made so far for continuously producing a wide amorphous alloy ribbon, but they were not satisfactory for reliable operation.
An object of the present invention is to limit the conditions mainly on the pouring nozzle side in order to stably produce a wide amorphous alloy ribbon.

[Means for Solving the Problems]

In the present invention, what is proposed as a production method for stably continuously producing a wide amorphous alloy ribbon is to directly melt a molten alloy directly on a cooling roll that rotates at a high speed through a pouring nozzle having a slit-shaped opening slit. When manufacturing the amorphous alloy thin plate by injecting into the nozzle and rapidly solidifying, by operating under the following conditions, the pool of water formed at the tip of the nozzle is not supported on the bottom surface of the nozzle, A method for producing an amorphous alloy ribbon, characterized in that molten metal is flowing down from a slot. Here, the state in which the molten metal flows down from the slot of the nozzle means that the molten metal flowing down from the slot does not contact the bottom surface of the nozzle.

The slot width of the opening slot is 0.5 to 1.5 mm, the bottom thickness of the front lip is 0.2 to 1.5 mm, and the bottom thickness of the rear lip is 0.2 to 5 mm.

The injection pressure of molten metal is 0.1 to 0.5 kgf / cm ² .

 The nozzle-roll spacing is 0.1 to 1 mm.

The moving speed of the cooling roll surface is 20 to 30 m / sec.

The front lip of the pouring nozzle has a bottom thickness of 0.2 to 1.5 mm
At the same time, the thickness of the front lip at a height of 2 mm or more from the bottom surface is at least 1.5 mm or more.

[Action]

The present invention provides at least 10 amorphous alloy ribbons having a width of 100 mm or more.
It was obtained from an operation experiment in which the plate was made for more than a minute and continuously wound.

In recent years, continuous plate-making of amorphous alloy thin films has not been so difficult. However, continuous plate-making and continuous winding to produce a coil-shaped amorphous alloy ribbon are not synonymous.

That is, since a large amount of ribbons are created very rapidly in a simple plate making experiment, when operating for a long time, not only partial cracks formed in the amorphous alloy ribbon but also instantaneous fracture Even it is never easy to judge its existence. However, when the amorphous alloy ribbon is wound under a certain tension, it is self-evident that even if there is a momentary break or a partial crack, it is not possible to continue the winding. Can not. In other words, on the assumption of continuous winding, it is possible to make an extremely strict evaluation on the plate making situation.

Some experimental facts that led to the present invention will be described together with specific experimental methods.

When the shape of the pool (paddle) of the molten metal at the tip of the pouring nozzle was investigated in detail during the stable plate-making of the amorphous alloy ribbon, the molten metal flow showed from the slit opening to the cooling roll as shown in FIG. It was injected almost immediately before the surface, solidified on the roll surface, and plate making was proceeding. That is, JP-A-53-53
No situation was observed in which the paddle was mechanically supported between the solidified front surface 16, the rear lip 13 and the front lip 14, as in FIG. 2 shown in Japanese Patent No. 525. Therefore, it was found that the thickness of the bottom surface of the front and rear lips need not be so large under the operating conditions of the present inventors.

FIG. 3 shows an example of an apparatus for producing an amorphous alloy ribbon according to the present invention. In the figure, reference numeral 1 is a tundish, 2 is a stopper, 3 is a pouring pipe, 4 is an outflow nozzle, 5 is a nozzle heater, 6 is an outlet slot, 7 is a cooling roll, and 8 is a molten metal reservoir.
The outlet nozzle 4 has an outlet slot 6 on the bottom wall, and communicates with the inside of the tundish 1 through the slot 2 at the upper opening of the molten metal reservoir 8. The stopper 2 controls closing and opening of the molten metal reservoir 8.

FIG. 1 is an enlarged view of the outlet slot 6 of the outflow nozzle 4, and particularly relates to the part specified in the present invention.

An alloy having a composition of Fe ₇₈ Mn ₁ B ₁₀ Si ₁₁ (atomic%) was melted in a high frequency induction melting furnace and the temperature of the molten metal was kept at 1300 ° C. This molten metal is used in the amorphous alloy ribbon manufacturing apparatus shown in FIG.
It is poured into a tundish 1 with an inner diameter of 400 mm preheated to 00 ° C, and the static iron pressure of the molten metal in the tundish 1 is 0.15 kgf / cm ²
When the temperature exceeds the limit, the stopper 2 is pulled up and the molten metal is heated to about 1350 ° C.
It was injected into the outflow nozzle 4 which was preheated.

As a result, opening slot 6 (slot width: 0.7mm, front lip bottom thickness: 0.7mm, rear lip bottom thickness: 2.5mm)
No nozzle clogging occurred, and the molten metal flow out onto the cooling roll 7 rotating at 27 m / sec did not cause a paddle break in the nozzle-roll gap of 0.35 mm, and the metal ribbon 15 was stabilized. The plate was made.

The amount of molten metal in the tundish 1 is almost 0.24 kgf / during operation.
When the flow rate was controlled to be cm ² , continuous plate making and winding were stably performed for 30 minutes, so the pouring was stopped and the operation was terminated. Paddle in this stable plate making process
The shape of 12 is as shown in FIG. 1 and was not supported by the front lip 14 and the rear lip 13.

The reasons for limitation of the present invention will be described below.

The lower limit of the lip thickness of the pouring nozzle is determined mainly by the need for mechanical strength at high temperatures. Due to the requirements of heat resistance, mechanical strength, and fineness of structure, general pouring nozzles have a fused silica, silicon nitride or boron nitride sintered body, or a silicon nitride / boron nitride composite sintered body, and Fine ceramic materials such as sialon are often used. Therefore,
It is difficult to perform too fine processing. On the other hand, as the opening slot portion, in order to improve the surface quality of the thin ribbon to be manufactured, it is necessary to secure a reliable slot shape at the nozzle tip surface. From these requirements, the lower limit of the front lip thickness is limited to 0.2 mm.

On the other hand, the upper limit of the front lip thickness was set as a condition for maintaining stable plate making. That is, when a wide amorphous alloy ribbon was manufactured for a long time, a phenomenon was observed in which only a part of the unsolidified material was scattered and adhered to the bottom surface of the front lip. These deposits are also formed due to the disturbance of the molten metal flow at the start of plate making, and sometimes large deposits on the bottom of the nozzle contact the cooling roll surface and destroy the nozzle. I was able to deal with it.

However, the deposits on the bottom of the front lip, which grow as the plate making progresses, have just emerged from the paddle part and scratched the amorphous alloy ribbon in the semi-molten state from the free surface side, creating cracks and the cause of fracture. This phenomenon could not be prevented only by devising the operating conditions.

FIG. 4 is an example of a micrograph of the deposit formed on the bottom surface of the front lip when the thickness of the front lip is 3 mm. When such a deposit grows along with the plate making and scratches the surface of the amorphous alloy ribbon that is in close contact with the cooling roll surface, the unevenness as shown in FIG. It was found to cause crystallization and embrittlement in the thick portion. Needless to say, if such a portion is formed in the amorphous alloy ribbon, continuous winding cannot be maintained.

In addition, this deposit may grow to 1 mm or more when the plate is made for a long time, which causes damage to the nozzle or damage to the cooling roll surface.

As a result of detailed observation of the formation phenomenon of deposits during the plate-making process, it was strange that no deposits were formed near the slot opening on the bottom surface of the front lip.
When the experiment was tried by changing the slot width of the opening and the gap between the nozzle and the roll, the position where deposits were formed from the slot opening was 1.
It never fell below 5 mm. Therefore, when the thickness of the bottom surface of the front lip was set to 1.5 mm or less, no deposit was formed on the bottom surface of the front lip. This is the reason why the thickness W ₁ of the bottom surface of the front lip 14 is limited to 1.5 mm or less.

If the thickness of the front lip is less than 1.5 mm, these problems will be solved, but the mechanical strength is insufficient and the front lip is damaged in front of the nozzle along with the molten metal flow during plate making. I will end up. Therefore, the thickness W ₂ of the front lip at the height H of 2 mm or more from the bottom surface of the nozzle is at least 1.5 m.
Mechanical strength is secured by making it m or more.

As mentioned above, since the paddle is not mechanically supported between the solidified front face, the rear lip and the front lip during the stable plate making, the thickness of the rear lip is not so large. The lower limit of the thickness of the back lip was limited to 0.2mm as it was not necessary.

The upper limit of the back lip thickness is not determined by the plate-making requirements. The nozzle-roll gap is a very important factor in stable plate making, and in many cases, the nozzle-roll distance is measured and controlled by an optical method before and during plate making. If the thickness of the bottom surface of the nozzle becomes too large, the measurement accuracy will decrease. Therefore, in the present invention, the upper limit of the thickness of the bottom surface of the rear lip is 5 mm.
Limited to

In the present invention, the opening width W of the pouring slot is limited to 0.5 mm to 1.5 mm. This is because if the width of the slit is smaller than 0.5 mm, nozzle clogging occurs and plate making is impossible, while if the width of the slit is larger than 1.5 mm, even if the gap between the nozzle and the roll is reduced, the slit opening part This is because the pouring amount of is too large and it is difficult to secure the optimum plate thickness of about 15 to 30 μm for maintaining stable plate making.

If the amorphous alloy ribbon is simply manufactured, it is possible to form a ribbon having a thickness of 50 μm or more. However, if the objective of the present invention is to produce a stable strip for a long time and continuous winding, the sheet thickness It has been found that the mechanical brittleness of large amorphous alloy ribbons in Si is fatal.

In the present invention, it is important that the molten metal formed at the nozzle tip is not supported by the bottom surface of the nozzle while the molten metal is sulphated from the slot of the nozzle during plate making.
That is, if the pool of water supports the bottom surface of the nozzle, the front lip of the nozzle is damaged, and the surface properties of the obtained amorphous metal ribbon are deteriorated, which is not preferable.

Further, in the present invention, the injection pressure of the molten metal is limited to 0.1 to 0.5 kgf / cm ² . When the injection pressure is 0.1 kgf / cm ² or less, not only is the nozzle clogged easily, but the pressure to press the molten metal against the cooling roll surface at the paddle part is insufficient. Entrapment was apt to occur, and as a result, the surface texture of the amorphous alloy ribbon roll surface side was not satisfactory. Also 0.5kgf / cm ²
With the above, the molten metal in the paddle spreads to the bottom surfaces of the front and rear lips and is mechanically supported by the lips. It is extremely difficult to keep this state stable, and it becomes a paddle break and it is not possible to continue stable plate making. Particularly, by scratching the front lip, the surface property of the amorphous alloy ribbon was remarkably deteriorated. This is the reason for limiting the injection pressure to 0.1 to 0.5 kgf / cm ² .

Further, the reason why the distance between the nozzle and the roll is limited to 0.1 to 1 mm in the present invention will be described. When making a wide amorphous alloy ribbon, a high temperature ceramic nozzle tip heated to about 1300 ° C approaches the surface of a cooling roll that rotates at a high speed of 20 to 30 m / sec. On the other hand, the distance between the nozzle and the roll cannot be measured directly in the vicinity of the center of the wide nozzle through which the molten metal flows out, so it is measured using the end of the nozzle. Furthermore, considering that thermal expansion of the cooling roll occurs with the start of plate making, it is industrially impractical to control the distance between the nozzle and roll during plate making to less than 0.1 mm. Is likely to collide with the cooling roll surface. When the distance between the nozzle and the roll exceeds 1 mm, the pouring flow shown in FIG. 1 is disturbed and the surface properties of the amorphous alloy ribbon are remarkably deteriorated.

In the present invention, the moving speed of the cooling roll surface is 20 to 30 m / sec.
Limited. The limitation on the low speed side was carried out in order to realize the high cooling rate necessary for producing the amorphous alloy ribbon, while at rotational speeds exceeding 30 m / sec, the wind pressure caused by the cooling roll was increased. Therefore, air was apt to be entrapped between the paddle and the roll surface, and as a result, the surface quality of the amorphous alloy ribbon roll surface side could not be satisfied. This is because in the present invention, the moving speed of the cooling roll surface is 20 to 20 seconds per second.
That is why it is limited to 30m.

Next, the present invention will be described based on examples.

Example 1 An alloy having a composition of Fe ₇₈ Mn ₁ B ₁₀ Si ₁₁ (atomic%) was melted in a high frequency induction melting furnace and the temperature of the molten metal was kept at 1300 ° C. This molten metal is used in the amorphous alloy ribbon manufacturing apparatus shown in FIG.
It is poured into a tundish 1 with an inner diameter of 400 mm preheated to 00 ° C, and the static iron pressure of the molten metal in the tundish 1 is 0.15 kgf / cm ²
When the temperature exceeds the limit, the stopper 2 is pulled up and the molten metal is heated to about 1350 ° C.
It was injected into the outflow nozzle 4 which was preheated.

Regarding the tip shape of the nozzle, the width of the opening slit is 0.8 m.
m, the bottom thickness of the front lip is 1.0 mm, the bottom thickness of the rear lip is 4.0 mm, and the front lip thickness is 3 mm at a height of 2 mm from the bottom, nozzle clogging at the exit slit 6 does not occur. Further, the molten metal flow that flowed out to the length of the cooling roll 7 rotating at 25 m / sec did not generate paddle flakes in the nozzle-roll gap of 0.30 mm, and stable plate production was performed. Further, an amorphous alloy ribbon having a plate thickness of about 24 μm and excellent surface properties was produced without damaging the nozzle during plate making. The amount of molten metal in the tundish 1 is almost 0 during operation.
When the flow rate was controlled to 24 kgf / cm ² , continuous plate making and winding were stably performed for 30 minutes, so the pouring was stopped and the operation was terminated.

Example 2 Regarding the shape of the tip of the nozzle, the width of the opening slit was 0.5 m.
m, the bottom thickness of the front lip is 0.4 mm, the bottom thickness of the rear lip is 2.0 mm, and the front lip thickness is 3 mm at a height of 2 mm from the bottom, the nozzle clogging at the exit slit 6 does not occur. Further, the molten metal flow flowing out onto the cooling roll 7 rotating at 27 m / sec did not cause a paddle break in the gap between the nozzle and the roll of 0.35 mm, and stable plate production was performed. Further, an amorphous alloy ribbon having a plate thickness of about 19 μm and excellent surface properties was produced without damaging the nozzle during plate making. When the flow rate was controlled so that the molten metal injection pressure in the tundish 1 would always be approximately 0.21 kgf / cm ² during operation, continuous plate making and winding were performed stably for 30 minutes. The operation was stopped and stopped.

Comparative Example 1 When the same process as in Example 1 was performed except that the width of the opening slit of the pouring nozzle was 0.2 mm, nozzle clogging occurred at the exit slit 6 and plate making could not be started. .

Comparative Example 2 Regarding the tip shape of the nozzle, the width of the opening slit is 0.6 mm,
The bottom thickness of the front lip is 2.0 mm, and the bottom thickness of the rear lip is
The same treatment as in Example 1 was performed except that the front lip thickness at the position of 4.0 mm and the height of 2 mm from the bottom surface was 3 mm, and the nozzle clogging at the exit slit 6 did not occur, and at 25 m / sec. The molten metal flowing out onto the rotating cooling roll 7 did not cause a paddle break in the nozzle-roll gap of 0.40 mm, and plate formation was started. Amorphous alloy ribbon with a plate thickness of about 22 μm was produced, but about 2 minutes after the start of plate making, the amorphous alloy ribbon immediately after plate making was cut off and the winding should be continued. I couldn't do that, so I interrupted the operation.

〔The invention's effect〕

The present invention regulates the tip shape of the pouring nozzle, the distance between the nozzle and the roll, the injection pressure and the moving speed of the cooling roll surface, so that the amorphous alloy can be used without mechanically instructing the paddle at the pouring nozzle tip. Since it is a method for producing thin strips, there is no clogging or damage to the nozzles, and there is no breakage of the amorphous alloy strip, which enables stable long-term continuous strip production and winding. Its significance is extremely large.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the present invention, FIG. 2 is an explanatory diagram of a conventional technique,
FIG. 3 is an explanatory view of the single roll method, FIG. 4 is a scanning electron microscope photograph of the deposit on the bottom surface of the front lip, and FIG. 5 is a sectional photograph of a scratched portion formed on the surface of the amorphous alloy ribbon. is there. 1 ... Tundish, 2 ... Stopper 3 ... Pouring pipe, 4 ... Outflow nozzle 5 ... Nozzle heater, 6 ... Exit slot 7 ... Cooling roll, 8 ... Molten pool 12 ... Paddle, 13 ... … Back lip 14 …… Front lip, 15 …… Metallic ribbon 16 …… Solid front

Claims (1)

[Claims] 1. A molten alloy is injected directly above a cooling roll rotating at a high speed through a pouring nozzle having a slit-shaped opening slot and rapidly cooled and solidified to produce an amorphous alloy ribbon under the following conditions. A method for producing an amorphous alloy ribbon, which is characterized in that the molten metal is produced from a slot of a nozzle. The slit width of the opening slot is 0.5 to 1.5 mm, the bottom thickness of the front lip is 0.2 to 1.5 mm, and the bottom thickness of the rear lip is 0.2 to 5 mm. The injection pressure of molten metal is 0.1 to 0.5 kgf / cm ² . And the distance between the nozzle and roll is 0.1 to 1 mm. The moving speed of the cooling roll surface is 20 to 30 m / sec. The thickness of the front lip at a height of 2 mm or more from the bottom surface is at least 1.5 mm or more.