JPS6340627B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is capable of producing a thin Fe-based amorphous alloy with a large thickness by rapidly solidifying a Fe-based alloy in a molten state on the surface of a moving cooling substrate. The present invention relates to a method of manufacturing a belt.

(Prior Art) The basic methods of rapidly cooling a metal (alloy) from a molten state to continuously produce a ribbon include a centrifugal quenching method and a melt spinning method represented by a single roll method.
In this method, a jet of molten metal is jetted onto the inner or outer circumferential surface of a rotating metal drum and rapidly solidified, thereby creating metal ribbons or wires all at once.
According to this method, the cooling rate is extremely fast, so if the alloy composition is appropriately selected, an amorphous metal (alloy) having a structure similar to that of liquid metal can be obtained.

Amorphous metals (alloys) are metal materials that have attracted practical attention due to their unique properties, but the range of applications has been limited by the fact that they can generally only be produced in thin sheets due to constraints on cooling rates. .

It is generally known that the critical thickness of amorphous alloys depends on the alloy composition, as reported by Hagiwara et al.
According to 351), when Fe-Si-B alloy is made amorphous using the single-roll method, which is one of the single-sided cooling methods, the plate thickness is as thick as Fe ₇₅ Si ₁₀ B ₁₅ of 250 μm;
It has been shown that the plate thickness decreases as the distance from this component increases.

However, it is known from experience that such a large thickness cannot be obtained for a ribbon having a practical width (20 mm or more). One of the reasons
One reason is that the cooling rate decreases as the width of the ribbon increases. That is, as the plate width increases, the thermal load on the cooling substrate increases, the substrate temperature increases, and as a result, the cooling rate decreases. A decrease in the cooling rate naturally reduces the thickness of the plate obtained in the amorphous state for the same alloy composition.

The reason why Hagiwara et al.'s results showed a large critical plate thickness is probably because their experiments were conducted with a narrow ribbon (approximately 1 mm width) with a fast cooling rate.

The thickness limit for wide materials with poor cooling conditions is
It is considerably smaller than the results of Hagiwara et al., 25 mm.
The width was approximately 45 μm. Even if the manufacturing conditions are changed to increase the plate thickness, it is not possible to obtain a good material. In other words, the manufacturing parameters that change the board thickness in the conventional single-sided cooling method are (i) the width of the nozzle opening (length in the direction of substrate movement), (ii) molten metal ejection pressure,
(iii) the distance between the nozzle and the cooling board, and (iv) the moving speed of the cooling board, but it has not been possible to obtain a thickness exceeding 45 μm by simply changing these parameters. If an attempt was made to forcibly make the plate thicker than the appropriate parameter range, the shape, surface quality, and properties (magnetic and mechanical properties) of the resulting ribbon deteriorated.

It has been considered technically difficult to produce a highly practical material with a large width and thickness using the single-sided cooling method, but recent advances in manufacturing technology have made it possible to produce thick amorphous materials exceeding 50 μm. It has also become possible to manufacture One is a method already proposed by the present inventors (Japanese Patent Application No. 58-216287), in which a plurality of slot-shaped openings are formed so that the distance between adjacent slots in the direction of movement of the board is 4 mm or less. This method uses nozzles installed in parallel. Using this method, when the plate width is 25 mm, an amorphous material with a plate thickness of about 75 μm can be obtained.
Fe _80.5 Si _6.5 B ₁₂ C ₁ alloy was obtained. However, a plate thickness that significantly exceeds this value cannot be achieved by simply increasing the number of slots, increasing the ejection pressure, or slowing down the roll circumferential speed, which can be easily recalled from experience or known methods. Nakatsuta.

It is also reported by Liebermann et al. that it has become possible to manufacture amorphous alloys with a thickness of 50 μm or more. This report was published in the Journal of Applied Physics vol.55 (1984
year) No.6 P.1787. Among them, they are amorphous with a plate width of 25.4 mm and a maximum plate thickness of 82 μm.
It has been revealed that Fe ₈₀ Si _3.5 B _14.5 C ₂ alloy has been created. However, this paper does not disclose a specific manufacturing method.

At present, there are two examples of wide and thick amorphous ribbons, but in any case, there is no method to manufacture ultra-thick materials that are wide and have a thickness that significantly exceeds 80 μm. It had not been disclosed.

(Problems to be Solved by the Invention) The purpose of the present invention is to solve the problem in that it is relatively difficult to manufacture thick plates.
The object of the present invention is to provide a method for stably producing a wide and thick Fe-based amorphous alloy, and a method for producing an extremely thick amorphous material that exceeds the conventional thickness limit.

(Means and effects for solving the problems) The method of the present invention is to transfer molten metal (alloy) to a moving cooling substrate, for example, a rotating single roll (hereinafter referred to as a single roll) made of Cu or Cu alloy. This invention relates to a method for producing a thin ribbon of an Fe-based amorphous alloy by ejecting it onto the outer peripheral surface of a roll (abbreviated as a roll) and rapidly solidifying it.

That is, the present invention is an improvement of Japanese Patent Application No. 58-216287, which has already been proposed by the present inventors.

The present invention will be explained below with reference to the drawings. 1st
The figure shows an example of an apparatus for carrying out the method of the present invention, in which 1 is a crucible, 2 is a roll constituting a cooling substrate, and the molten metal in the crucible 1 is jetted onto the outer peripheral surface and rapidly cooled to form an amorphous metal. A quality alloy ribbon 10 (hereinafter simply referred to as a ribbon) is manufactured. 3 is a roll surface temperature detector such as a contact thermometer. 4 is a cooling roll for cooling the free surface of the produced ribbon 10; 5 is a cooling roll for cooling the surface of the roll 2; the roll is cooled by cooling water supplied from a cooling water supply pipe 6; be done. 7 is a gas jet nozzle for drying the surface of the roll 2, 8 is a jet pressure switching controller applied to the crucible 1, and 9 is a water flow rate controller for internal cooling of the roll 2; It is controlled by the output of the surface temperature detector 3. Therefore, the roll 2 is rotated in the direction of the arrow in Fig. 1, and the surface temperature of the roll 2 is detected by the roll surface temperature detector 3, and the temperature is within the appropriate temperature range, that is, the crystallization start temperature of the alloy to be manufactured.
When Tx (℃), Tx (℃) -400℃ to Tx (℃)
water flow controller 9 to maintain the temperature within the range of −200°C;
The amount of cooling water supplied to the roll cooling roll 5 is controlled. Therefore, by jetting the molten metal from the nozzle of the crucible 1 onto the outer peripheral surface of the roll 2, a thick amorphous alloy ribbon can be manufactured. In addition, the nozzle for spouting the molten metal used at this time has a plurality of slot-shaped openings arranged in parallel on the surface facing the roll 2 so that the interval between adjacent slots is 4 mm or less in the direction perpendicular to the direction of movement of the cooling board. Use the one you made. As an example, a conceptual diagram of a quadruple nozzle is shown in Fig. 2.

The purpose of using such a multilayered slot nozzle is to produce a thick ribbon. The effect of increasing the thermal contact between the molten metal puddle (hereinafter referred to as a puddle) formed on the cooling substrate and the substrate increases the solidification rate, and expands the puddle in the longitudinal direction (movement direction) to form a roll. It acts to lengthen the contact time with 2. It is impossible to obtain the same effect from a conventional single slot nozzle.
There is a limit to paddle enlargement when using a single slot nozzle. The slot width (the length of the opening measured in the direction of movement) cannot be arbitrarily increased in order to enlarge the paddle in the longitudinal direction. If the paddle is expanded beyond the appropriate width (usually 0.3 to 0.8 mm), the paddle becomes unstable and a ribbon with excellent shape and surface properties cannot be stably produced. For this reason
In order to produce thick ribbons exceeding 90 μm, it is essential to use a multi-slot nozzle.

Therefore, as illustrated in FIG. 2 above, the interval between adjacent slot-shaped openings is 4.
Use multiple slot nozzles arranged in parallel so that the diameter is less than mm.

Along with the use of multiple nozzles, control of the surface temperature of the roll 2 during casting is also an important requirement. The purpose of this is to rapidly cool the molten metal to below the vitrification temperature while maintaining good thermal contact between the paddle and the roll, and it is important to meet the conditions from the start of casting.

Therefore, in the present invention, as a specific condition for the roll temperature, in order to make the plate thickness 90 μm or more, the surface temperature just before contacting the paddle (actually,
(approximate the temperature measured about 10 cm in front) is Tx
It is characterized by being controlled to be within the range of -400°C to Tx -200°C. Here, Tx is the crystallization initiation temperature (°C) of the alloy to be cast, and is measured using a differential thermal analyzer. It is defined as the temperature at which the exothermic peak rises when the heating rate is 10°C/min.

The appropriate temperature range for the roll in the present invention was determined experimentally, and the reason why it depends on the Tx of the alloy is considered as follows. First, the lower limit of the temperature range seems to be related to the thermal contact (wettability) between the molten metal and the roll. It has been confirmed from the air pockets on the roll surface of the fabricated ribbon that the higher the Tx composition, the worse the wettability at low temperatures. On the other hand, the upper temperature limit is related to the quenching rate. In order to make the alloy amorphous, it must be rapidly cooled to a temperature below the vitrification temperature, but if the roll temperature is too close to the vitrification temperature, the prescribed cooling rate and therefore the rapid cooling required to form a thick plate will be lower. The solidification rate cannot be maintained. The upper limit temperature Tx - 200°C is a necessary condition to ensure a fast cooling rate. Note that in general amorphous alloys, the vitrification temperature has been shown to be close to Tx, so Tx, which is easy to measure, is used instead of vitrification temperature.

In order to maintain the surface temperature of the roll within the range specified by the present invention, specifically, when using a water-cooled roll, it is possible to control the temperature to some extent by adjusting the amount of water supplied and the water temperature. However, there are cases where it is not possible to maintain the roll surface temperature within the above temperature range simply by adjusting the amount of water and the like. In particular, when attempting to produce a ribbon with a thickness of 90 μm or more, the thermal load may exceed the cooling capacity of the cooling roll, and the temperature of the roll surface will continue to rise beyond the above temperature range. If the roll surface temperature exceeds the appropriate range, the cooling rate required to obtain a thick plate will not be achieved.

In order to maintain the roll temperature within an appropriate range in order to secure the cooling rate necessary to obtain a plate thickness of 90 μm or more, one or both of the following auxiliary cooling methods must be used in combination. It is necessary to adopt it.

1. Auxiliary cooling from the roll surface 2. Cooling from the free surface of the ribbon Specific means for the auxiliary cooling can be carried out by the method disclosed in Japanese Patent Application Laid-Open No. 10452/1983.

Too low roll surface temperature is also undesirable. Especially in the early stages of casting, the rolls are cold and the cooling rate is slow. For this reason, even if an amount of molten metal corresponding to the desired thickness is supplied, a ribbon of a predetermined thickness will not be formed, and the paddle will become unstable due to the excess molten metal, making it impossible to form a ribbon with a good shape. After conducting various experiments and studies to find solutions to the problems encountered in the production of thick materials, the present inventors have invented the following completely new and effective means. This is a method in which preliminary casting is performed before the actual casting, which aims for a thickness of 90 μm or more. The purpose of precasting is simply to raise the temperature of the roll surface to an appropriate range, and can be carried out, for example, by the following two specific methods.

1 Start the molten metal ejection pressure at a low pressure, and when the roll surface temperature falls within the appropriate range, increase it to the specified pressure.

2. Supply molten metal from an auxiliary crucible that is different from main crucible 1, and when the temperature of the roll surface rises to an appropriate range, stop supplying molten metal from the auxiliary crucible, and at the same time, thick material from main crucible 1. Started making books.

The reason why conventionally proposed roll preheating methods cannot be adopted here is that conventional methods use slow heating methods such as heating with a burner or contact with high-temperature gas or solids, which causes the inside of the roll to reach a high temperature. Experiments have revealed that the cooling effect of

However, irradiation with a laser was an effective means for rapidly heating only the surface layer of the substrate.
In this case, the irradiation position is preferably behind the paddle (in the opposite direction to the exit side of the ribbon) and as close to the paddle as possible because the incident energy can be small.

It is also effective to seal the space including the paddle and its vicinity in a pressurized atmosphere. The paddle is pressed tightly against the roll, resulting in increased heat transfer from the paddle to the substrate and faster solidification rate.

(Example) Next, an example will be given and explained.

Example 1 The composition Fe _80.5 Si _6.5 B ₁₂ C ₁ was produced using a quenched metal ribbon manufacturing apparatus equipped with a Cu alloy cooling roll with a diameter of 600 mm, a blowout gas pressure switching mechanism, and a contact thermometer to measure the roll surface temperature. (at%) alloy (Tx=490℃)
was cast into a thin strip. However, a quadruple slot nozzle (width: 0.4 mm, length: 25 mm, spacing: a: 1 mm) as shown in FIG. 2 was used as the nozzle for spouting the molten metal. The casting conditions were a roll peripheral speed of 18 m/sec, a distance of 0.2 mm between the roll and the bottom of the nozzle, and a primary pressure of 0.1 kg/sec.
Preliminary casting was carried out at ^cm2 , and immediately after the roll surface temperature measured at a position 10cm behind the nozzle reached 110℃, which is within the appropriate range for the alloy, the secondary pressure was changed to 0.25Kg/ ^cm2 , and main casting was started. It started. The width of the manufactured board is 25.5
The average thickness was 92 μm. It was confirmed by X-ray diffraction that both the front and back sides of the plate were in an amorphous state. This thickness is as wide as 25 mm, which is a large thickness that could not be obtained using conventional technology for an amorphous material. In addition, the bending fracture strain t/(2r−
t) was 0.03, an epoch-making value for this plate thickness.

Example 2 Composition using the same manufacturing equipment as Example 1
An alloy of Fe ₇₈ Si ₁₀ B ₁₀ C ₂ (at%) (Tx = 525°C) was cast into a ribbon. At that time, the same nozzle as in Example 1 was also used. The casting conditions were a roll peripheral speed of 18 m/sec,
The distance between the roll and the bottom of the nozzle is 0.2 mm, and preliminary casting is performed at a primary pressure of 0.12 Kg/cm ² . Immediately after the roll surface temperature reaches 130°C, which is within the appropriate range for the alloy, the secondary pressure is 0.25. We switched to Kg/cm ² and started actual casting. The manufactured board has a width of 25.3 mm and an average thickness.
It was 95 μm. When the structure of the front and back sides of the plate was examined by X-ray diffraction, both showed a halo pattern, confirming that they were amorphous. When the as-cast plate was subjected to a bending test, the fracture strain was 0.02. As described above, the amorphous alloy produced by the method of the present invention does not have the brittleness characteristic of thick materials.

Example 3 Ultra-quenched metal ribbon manufacturing equipment equipped with a Cu alloy cooling roll with a diameter of 1000 mm, an auxiliary roll that cools the free surface of the ribbon, a blowout gas switching mechanism, and a contact thermometer that measures the roll surface temperature. Therefore, an alloy having the same composition as in Example 1 was manufactured into a ribbon. However, the nozzle is a 5-fold slot nozzle (D0.4mm, L25mm, A1
mm) was used. Casting conditions are roll peripheral speed 18m/sec,
Preliminary casting was performed with a primary pressure of 0.1 Kg/cm ² with a distance of 0.2 mm between the roll and the bottom of the nozzle, and a secondary pressure of 0.25 Kg immediately after the roll surface temperature measured 20 cm behind the nozzle reached 100°C. / ^cm2 and started casting. The width of the manufactured board is 25.8mm and the thickness is average
It was 115 μm. It was confirmed by X-ray diffraction that both the front and back sides of the plate were in an amorphous state. This thickness is a large plate thickness that could not be obtained using conventional techniques for a 25 mm wide amorphous material.

(Effects of the Invention) As explained above, by implementing the method of the present invention, it becomes possible to stably produce a Fe-based amorphous alloy material with a large thickness, and at the same time
It has now become possible to produce extremely thick Fe-based amorphous alloy ribbons that could not be obtained using conventional techniques. Ultra-thick amorphous materials can be used as high-strength materials such as stacked iron core materials and spring materials, or as structural materials, expanding the field of application of Fe-based amorphous alloys.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of an apparatus for carrying out the method of the present invention, and FIG. 2 is a conceptual diagram of a quadruple nozzle. 1: Crucible, 2: Roll, 3: Roll surface temperature detector, 4: Cooling roll for ribbon, 5: Cooling roll on the roll surface.

Claims (1)

[Claims] 1. In a method for producing a ribbon of Fe-based amorphous alloy by ejecting molten Fe-based alloy onto the surface of a moving cooling substrate and rapidly solidifying it, a plurality of slot-shaped openings are used as nozzles for ejecting the molten metal. Using nozzles arranged in parallel in the direction of movement of the cooling substrate, the surface temperature of the cooling substrate during casting is controlled between Tx (℃) -400℃ and Tx -200℃ (where Tx is the crystallization start temperature of the alloy to be cast). Width characterized by holding in
A method for manufacturing an Fe-based amorphous alloy ribbon with a thickness of 20 mm or more and a plate thickness of 90 μm or more.