JP2010099683A - Apparatus for producing amorphous alloy foil strip and method for producing amorphous alloy foil strip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for producing an amorphous alloy foil strip having a large plate thickness in an industrial scale, and to provide a method for producing the amorphous alloy foil strip. <P>SOLUTION: The apparatus 1 for producing the amorphous alloy foil strip S includes a cooling roll provided with a pair of cooling zones 13a and 13b via a forbidden zone 18, a drive means 11 for rotating the cooling roll, and a crucible 14 for alternately supplying molten alloy A to the outer circumferential surface of the cooling zones 13a, 13b. The crucible 14 is movable along a rail 16. While rotating and water cooling the cooling zones 13a, 13b, molten alloy is alternately supplied to the cooling zones 13a, 13b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an amorphous alloy foil strip manufacturing apparatus and an amorphous alloy foil strip manufacturing method, and more particularly to an amorphous alloy foil strip manufacturing apparatus and an amorphous alloy foil provided with a cooling roll. The present invention relates to a method for manufacturing a belt.

  Conventionally, it has been studied to use an iron-based amorphous alloy with low power loss for the iron core of a transformer or a motor, and some transformers have been put into practical use. However, it has not been put to practical use in motors, and transformers are limited to wound iron cores. This is because the thickness of the amorphous alloy foil strip produced on an industrial scale is as thin as 25 μm or less. If thick foil strips are manufactured industrially, they can be applied to motors and iron core transformers. Thickening the foil strip improves the work efficiency of the iron core machining process and increases the space factor. Further, the mechanical strength of the iron core is remarkably increased by improving the rigidity of the foil strip. In other words, it can be applied to motors and stacked iron cores in which foil strips are laminated to form an iron core.

  The most common method for producing amorphous alloys is to rapidly cool the molten alloy by bringing the molten alloy into contact with the outer surface of the roll while rotating a metal or alloy roll with high thermal conductivity at high speed. Then, a roll liquid quenching method for solidifying in a foil strip shape. However, the thickness of the amorphous alloy foil strip that can be manufactured by the roll liquid quenching method is severely limited, and a foil strip that is sufficiently thick cannot be manufactured.

  Therefore, the present inventors have developed a multiple slit nozzle method in which a plurality of slits are arranged along the circumferential direction of the roll, and disclosed in Patent Document 1. According to this multiple slit nozzle method, the molten alloy discharged from each slit forms a plurality of hot water pools (paddles) corresponding to the number of slits in a narrow space between the nozzle and the roll. The vicinity of the contact surface with the roll in the first paddle counting from the upstream is cooled on the outer peripheral surface of the roll, and the supercooled fluid layer with increased viscosity is drawn out by the roll, and the downstream paddle overlaps therewith. . Since the temperature of the fluid layer drawn out from the upstream paddle is lowered before the fluid layer is associated with the downstream paddle, the downstream paddle is cooled by the fluid layer, and the portion having increased viscosity is drawn out. By repeating this, a thick foil strip is formed. Since the fluid layers overlap each other in a liquid state, the interfaces are mixed together, and an integrated amorphous alloy foil strip having no boundary between the layers is obtained.

  However, the multiple slit nozzle method also has the following problems. That is, the roll liquid quenching method includes a method using a non-water cooling roll and a method using a water cooling roll. The non-water-cooled roll cools the molten alloy by the heat capacity of the roll itself. When the non-water-cooled roll is used, the molten alloy can be efficiently cooled in a state where the roll temperature at the initial stage of production is low, and a certain amount of thick amorphous alloy foil strip can be produced. However, the non-water-cooled roll cannot be used for a long time because the cooling efficiency decreases as the roll temperature rises. For this reason, it is unsuitable when producing an amorphous alloy foil strip industrially.

  For this reason, it is preferable industrially to use a water-cooled roll. Since the water-cooling roll has a built-in water-cooling mechanism, the heat can be exhausted through the cooling water even if the heat capacity of the roll itself is small. However, it was difficult to mass-produce a thick amorphous alloy having a plate thickness exceeding 25 μm even on a water-cooled roll on an industrial scale.

JP 60-108144 A Japanese Utility Model Publication No. 6-86847 Japanese Patent Publication No. 61-059817

  An object of the present invention is to provide an amorphous alloy foil strip manufacturing apparatus and an amorphous alloy foil strip manufacturing method capable of manufacturing an amorphous alloy foil strip having a large thickness on an industrial scale. It is.

  According to an aspect of the present invention, the apparatus includes: a cooling roll; a driving unit that rotates the cooling roll; and a supply unit that supplies the molten alloy to the outer peripheral surface of the cooling roll. A first cooling zone that constitutes a part of the outer peripheral portion of the cooling roll and circulates in the circumferential direction of the cooling roll, and is spaced from the first cooling zone with a forbidden band in the axial direction of the cooling roll Then, an amorphous alloy foil strip manufacturing apparatus is provided in which the molten alloy is alternately supplied to a second cooling zone that circulates in the circumferential direction of the cooling roll. A forbidden band interposed between the two cooling zones is provided to limit the heat transfer between the cooling zones.

  According to another aspect of the present invention, an alloy is formed with respect to the first cooling zone that constitutes a part of the outer peripheral portion of the cooling roll and rotates around the circumferential direction of the cooling roll while rotating the cooling roll. While rotating the cooling roll, the first step of supplying the molten metal is separated from the first cooling band with a forbidden band in the axial direction of the cooling roll, and circulates along the circumferential direction of the cooling roll. And a second step of supplying the molten alloy to a second cooling zone, wherein the first step and the second step are performed alternately, and the method for producing an amorphous alloy foil strip Is provided.

  According to the present invention, an amorphous alloy foil strip manufacturing apparatus and an amorphous alloy foil strip manufacturing method capable of manufacturing an amorphous alloy foil strip having a large plate thickness on an industrial scale are provided. be able to.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view illustrating an apparatus for manufacturing an amorphous alloy foil strip according to this embodiment.
FIG. 2 is a cross-sectional view illustrating the structure of the cooling roll in FIG.
FIG. 3 is a cross-sectional view illustrating a portion where the molten alloy contacts the cooling roll in FIG.
4 is a conceptual diagram showing a path of cooling water for cooling the cooling roll in FIG.
FIG. 5 is a timing chart illustrating a method for manufacturing an amorphous alloy foil strip according to this embodiment, with time on the horizontal axis and a cooling zone on the vertical axis.

  As shown in FIG. 1, an amorphous alloy foil strip manufacturing apparatus 1 according to this embodiment mainly manufactures an iron-based amorphous alloy foil strip (hereinafter also simply referred to as “foil strip”) S. Is. In the manufacturing apparatus 1, a cooling roll 13 having a large thickness through which cooling water W (see FIG. 3) flows is installed. The cooling roll 13 is pivotally supported by rotating shaft members 12a and 12b (hereinafter also collectively referred to as “rotating shaft member 12”), and the rotating shaft member 12 is connected to a driving unit 11 that shares the rotating shaft. The driving means 11 has a built-in motor (not shown), and rotates the cooling roll via the rotating shaft member 12. The rotating shaft member 12 and the cooling roll 13 are supported by bearings 41a and 41b.

  As shown in FIGS. 1 and 2, two cooling zones 13 a and 13 b are provided on the outer peripheral portion of the cooling roll 13 with the forbidden zone 18 interposed therebetween. The cooling zones 13a and 13b are fixed to a support mechanism 31 made of a strong metal alloy. The support mechanism 31 is coupled to the roll driving means 11, and the cooling belts 13 a and 13 b are given a rotational force by the roll driving means 11.

  The cooling zones 13a and 13b are formed of a metal or alloy having a high thermal conductivity, and are formed of, for example, copper or a copper alloy. The thermal conductivity of copper is 395 W / (m · K) at 100 ° C. The cooling zones 13a and 13b may be formed of a Be—Cu alloy or a Cr—Cu alloy, and the thermal conductivity of these copper alloys is 150 to 300 W / (m · K). On the other hand, the forbidden band 18 may be integrally formed of the same material as the cooling bands 13a and 13b, or may be formed of a material different from the cooling bands 13a and 13b. For example, when the forbidden band 18 is formed of a material different from that of the cooling bands 13a and 13b, the thermal conductivity of the material is, for example, 10 W / (m · K) or more. Examples of the material for forming the forbidden band 18 include carbon steel (thermal conductivity: 48.5 W / (m · K)), 18-8 stainless steel (thermal conductivity: 16.5 W / (m · K)). And copper alloys such as brass (thermal conductivity: 128 W / (m · K)).

  In the manufacturing apparatus 1, a crucible 14 for holding the molten alloy A (see FIG. 3) is provided, and the molten alloy A in the crucible 14 is placed outside the crucible 14 at the lower end of the crucible 14. A nozzle 15 that discharges toward is attached. The discharge port of the nozzle 15 is disposed close to the outer peripheral surface of the cooling roll 13. Here, the crucible is not limited to the one shown in FIG. 1 and includes all means for storing and supplying molten metal, for example, one that can receive molten metal from an alloy melting device and supply the alloy to a cooling roll through a nozzle. Is called a crucible. An apparatus that includes a nozzle in the melting apparatus and can supply the molten metal directly is also included.

  The nozzle 15 is, for example, a multiple slit nozzle as shown in FIG. That is, the shape of the discharge port of the nozzle 15 is a shape in which a plurality of, for example, two slits 17 a and 17 b are arranged along the circumferential direction of the cooling roll 13. The longitudinal direction of each slit 17 a and 17 b is parallel to the axial direction (roll width direction) of the cooling roll 13. Further, the distance between the slits 17a and 17b is, for example, 10 mm (millimeters) or less, for example, 6 mm or less. The nozzle 15 may be a multiple nozzle in which three or more slits are formed in the discharge port, or a single slit nozzle in which only one slit is formed.

  The nozzle 15 is formed of a refractory material that is difficult to wet the molten alloy A, and is formed of, for example, boron nitride, zirconia, or alumina. As a result, the slit 17 is not easily blocked by the molten alloy A. In addition to these refractories, even a refractory that gets wet with the molten alloy can be used as a material for the nozzle 15 if the surface is coated with a material that is difficult to wet the molten alloy by thermal spraying or the like. For example, silicon nitride has excellent strength and thermal shock resistance. Further, the composite material of silicon carbide and boron nitride is conductive in addition to heat resistance, and it is easy to maintain the temperature of the nozzle during standby. However, since these materials react with iron in the molten alloy, it is necessary to coat them with a substance that is difficult to wet, such as boron nitride, zirconia, or alumina.

  Further, the manufacturing apparatus 1 is provided with moving means 16 for moving the crucible 14 along the axial direction of the cooling roll 13. The moving means 16 moves the crucible 14 between a position where the nozzle 15 faces the cooling zone 13a and a position where the nozzle 15 faces the cooling zone 13b.

  FIG. 4 shows a simplified path of the cooling water W in the amorphous alloy foil strip manufacturing apparatus according to this embodiment. In order to keep the cooling water W below a predetermined temperature, for example, room temperature, during the casting, a cooling means 43 for cooling the cooling water is provided in the course of the cooling water W, for example, in the water storage tank 42. As a cooling means, there are a method of installing a device applying a heat pump, a method of charging a substance having a temperature lower than room temperature such as ice into the water storage tank 42, and the like. The cooling water is supplied from the water storage tank 42 to the water channel 24 of the cooling roll 13 through the water supply pipe 25, circulates in the cooling roll 13, and then returned from the water path 24 to the water storage tank 42 through the drain pipe 26. The cooling water is cooled by the cooling means 43 during the circulation. The water channel 24 is also formed in the forbidden zone 18 in addition to the cooling zones 13a and 13b.

  The configurations of the water supply pipe 25 and the drain pipe 26 are not limited to the configuration shown in FIG. 2, and can be any configuration that can be connected to the cooling roll 13. For example, as shown in FIG. 2, the water supply pipe 25 and the drain pipe 26 may constitute a double pipe. In this case, a cooling water circulation system including the water storage tank 42, the cooling means 43, the water supply pipe 25, the water channel 24, and the drain pipe 26 is provided independently for each of the cooling zone 13a and the cooling zone 13b. This is because the cooling zone 13a and the cooling zone 13b are thermally separated. Further, the water supply pipe 25 may be connected to one end of the cooling roll 13 in the axial direction, and the drain pipe 26 may be connected to the other end. In this case, the water supply pipe 25 passes through the central portion 32 of the support mechanism 31 of the cooling roll 13 in the axial direction. Further, for example, when viewed from the axial direction of the cooling roll 13, the water supply side water channel branches in two opposite directions from the center of the cooling roll 13 toward the outer peripheral surface, and the drain side water channel is the outer periphery of the cooling roll 13. It merges from two directions orthogonal to the direction in which the branch on the water supply side extends from the surface toward the center. That is, when viewed from the axial direction of the cooling roll 13, the branch path connecting the central portion and the outer peripheral portion of the cooling roll 13 has a cross shape.

Next, an operation of the manufacturing apparatus 1 according to this embodiment configured as described above, that is, a method for manufacturing an amorphous alloy foil strip according to this embodiment will be described.
First, as shown in FIG. 1, the cooling roller 13 is rotated via the rotating shaft member 12 by driving the driving unit 11. Next, the molten alloy A is discharged from the crucible 14 through the nozzle 15 disposed close to the outer peripheral surface of one cooling zone of the cooling roll 13, for example, 13 a at a predetermined interval. Thereby, the paddle P is formed between the nozzle 15 and the cooling zone 13a. Then, of the molten alloy forming the paddle P, the molten alloy located in the vicinity of the contact surface with the cooling zone 13 a is cooled to increase the viscosity, and is drawn from the paddle P by the rotation of the cooling roll 13. The drawn alloy is a supercooled liquid at this point, but is rapidly cooled by the cooling roll 13 to become the glass transition temperature or lower and becomes an amorphous alloy foil strip S. In the case of an iron-based alloy, the cooling rate required for the foil strip (or supercooled liquid) drawn from the paddle P to be amorphous is, for example, 1 × 10 ⁵ ° C./second or more.

  In the present embodiment, as shown in FIG. 3, two slits 17 are formed in the nozzle 15. For this reason, the plate | board thickness of the foil strip formed becomes thick compared with the case where a single slit is used, even if the circumferential speed of a cooling roll is the same. That is, productivity is high. The reason why the multi-slit nozzle is thicker than the single-slit nozzle at the same roll peripheral speed is that the paddle P is divided into a plurality of parts so that the contact area with the cooling zone increases and the cooling zone becomes This is because the heat flow to be transmitted can be dispersed.

  As shown in FIG. 4, heat transferred from the molten alloy and the foil strip to the cooling roll 13 to form the amorphous alloy foil strip is transferred from the outer peripheral portion of the cooling strip 13a to the inside of the roll, and passes through the water channel 24. It is transmitted to the circulating cooling water W. The heat transferred to the cooling water is collected in the water storage tank 42 together with the cooling water through the drain pipe. That is, the heat of the molten alloy A is discharged through the route of the molten alloy A → the cooling roll 13 → the cooling water W.

  When the temperature of the cooling zone 13a reaches a predetermined value (Th) with the casting of the foil strip S, the nozzle 15 is closed and the discharge of the molten alloy A is stopped. After stopping, the moving means 16 moves the crucible 14 quickly and brings it close to the outer peripheral surface of the cooling zone 13b. Then, the supply of the molten metal A is resumed. Thereby, the foil strip S is cast using the cooling zone 13b. At this time, the cooling zone 13b is heated as the foil strip S is cast, but the cooling zone 13a is rapidly cooled by the cooling water. Then, when the temperature of the cooling zone 13b reaches a predetermined value (Th), the supply of the molten metal A is stopped, the crucible 14 is quickly moved, and is brought close to the outer peripheral surface of the cooling zone 13a. Then, the molten metal is supplied again. By this time, the cooling zone 13a has been sufficiently cooled. For example, it has reached room temperature. When the temperature of the cooling zone 13a again exceeds a predetermined temperature (Th), the supply of the molten alloy A is stopped, the crucible 14 is moved to a position corresponding to the cooling zone 13b, and casting is continued. By repeating the above operation alternately, the cooling rate required for amorphization can be secured. In particular, it is effective for producing a foil strip having a large thickness (30 μm or more). On the other hand, until now, since a cooling roll having a single cooling zone was used, continuous casting of a thick foil strip of 30 μm or more was not possible.

  In the above-described example, the form in which the crucible 14 is moved from the position facing the cooling zone 13a to the position facing the cooling zone 13b is exemplified. However, the nozzle is obtained by moving the cooling roll 13 along the rotation axis. It is also possible to move the cooling zone facing to the cooling zone 13a from the cooling zone 13a.

  Thus, while rotating the cooling roll 13, the first step of supplying the molten alloy A to the outer peripheral surface of the cooling zone 13a and the supply of the molten alloy A are interrupted so that the crucible 14 faces the outer peripheral surface of the cooling zone 13b. The foil strip S having a large thickness can be manufactured almost continuously on an industrial scale by repeating the second step of supplying the molten alloy A to the outer peripheral surface of the cooling zone 13b. FIG. 5 illustrates an operation mode in this embodiment. As shown in FIG. 5, when casting is performed in one cooling zone, the other cooling zone is in a cooling process with cooling water.

Hereinafter, numerical examples in the present embodiment will be shown.
FIG. 6 is a ternary composition diagram illustrating the composition of the iron-based amorphous alloy foil strip produced in this embodiment. The iron-based amorphous alloy foil strip S manufactured in the present embodiment has a width of, for example, 60 mm or more, and a thickness (plate thickness) of, for example, 30 μm (micrometer) or more, for example, 33 μm or more, for example, 40 μm or more. is there. In the present specification, the thickness of the foil strip is defined by the weight plate thickness. The weight plate thickness is a value obtained by dividing the weight of the foil strip by the area and density of the foil strip.

  Furthermore, as shown in FIG. 6, the composition of the iron-based amorphous alloy foil strip S is obtained by adding, for example, silicon (Si) and boron (B), which are semimetals, to iron (Fe). is there. When this foil strip S is used for electromagnetic applications, the concentration of iron is preferably 70 atomic% or more. The composition of the foil strip is, for example, the composition in the region R surrounded by the broken line in FIG. 6, that is, the iron content is 70 to 81 atomic%, the silicon content is 3 to 17 atomic%, boron The composition is such that the content is 9 to 23 atomic% and the glass transition temperature Tg is 500 ° C. or higher. Here, the sum of iron, silicon, boron, and inevitable impurities is 100 atomic%. A part of iron may be substituted with cobalt (Co) or nickel (Ni). The total amount of substitution is 20 atomic% or less. Further, a part of silicon or boron may be substituted with 2.0 atomic% or less of carbon. However, the carbon substitution amount is set such that the glass transition temperature Tg is 500 ° C. or higher. That is, the composition of the molten alloy A has an iron content of 70 to 81 atomic%, a silicon content of 1 to 17 atomic%, a boron content of 7 to 23 atomic%, The composition may be such that the content is 2 atomic% or less and the glass transition temperature Tg is 500 ° C. or higher.

The reason why the glass transition temperature Tg is a requirement for composition selection is as follows. Conventionally, the ease of making an alloy amorphous (amorphous forming ability) has been evaluated by the ratio of the melting point Tm of the alloy to the glass transition temperature Tg, Tg / Tm (here, absolute temperature). However, in practice, the contribution of the glass transition temperature Tg is more conspicuous than the melting point Tm, so the region R of the alloy composition is determined by the size of Tg. When the glass transition temperature Tg of the alloy is increased by 50 ° C., the limit thickness of the foil strip that can be made amorphous becomes at least 10% thicker. The measurement of the glass transition temperature Tg was difficult with an iron-based alloy, and thus the crystallization peak temperature T _p1 that was set to substantially the same temperature was used instead. The numerical value in FIG. 6 represents the crystallization peak temperature T _p1 (° C.).

Among the compositions in the region R shown in FIG. 6, specific groups for a group having a relatively high saturation magnetic flux density Bs, that is, a group having a saturation magnetic flux density Bs of 1.5 T (tesla) or more, and a group having a low hysteresis loss are shown. The composition is shown in Table 1. The hysteresis loss is a hysteresis loss Wh _13/50 at a frequency of 50 Hz (hertz) and a magnetic flux density of 1.3T. In Table 1, when Wh _13/50 having the composition shown in the right column is heat-treated under the optimum conditions, the value is 0.08 W / kg or less. Here, the hysteresis loss Wh _13/50 is a value measured with a single plate sample. In addition, the number shown in Table 1 has shown atomic% of each component.

  Further, the foil strip S may contain 0.01 to 1.0% by mass of tin (Sn). Although the crystallization of the foil strip starts from the surface, tin has a strong tendency to segregate on the surface and has the effect of suppressing the crystallization of the foil strip surface layer. Thereby, the deterioration of the magnetic characteristics accompanying crystallization is suppressed. Tin also has the effect of suppressing changes in magnetic properties over time.

Next, the manufacturing apparatus and manufacturing method according to the present embodiment will be described in detail.
The thickness of the cooling zones 13a and 13b is preferably 25 mm or more. Conventionally, the thickness of the cooling roll is designed on the premise of continuous long-time casting, and the thinner the thickness, the more advantageous it is for heat removal, and 10 mm or less has been adopted. For example, in Patent Document 2, the thickness of the cooling roll (cooling sleeve) is defined as 3 to 10 mm, and the reason is described. According to this, when the thickness exceeds 10 mm, the cooling rate is greatly reduced, the local embrittlement of the amorphous alloy foil band becomes severe, and in particular, a foil band having a thickness of 25 μm or more that can be bent and bent cannot be obtained. ing. In addition, when the thickness is 3 mm or less, it is considered that the thermal deformation of the cooling roll is large and the thickness of the quenched foil strip is uneven. Further, Patent Document 2 proposes a method of causing a jet of cooling water to collide with the inner surface of a roll as means for increasing the thickness of an amorphous alloy foil strip. However, even with this method, the effect of increasing the heat transfer coefficient between the roll and water is limited, and it has been difficult to produce an amorphous alloy foil strip having a thickness of more than 30 μm. Note that the thickness of the conventional cooling roll corresponds to the thickness of the cooling zone of the present embodiment.

  The reason why a thick amorphous alloy foil strip cannot be obtained with a conventional thin cooling roll will be explained based on experimental knowledge and heat transfer calculation. FIG. 7 (a) schematically shows the time change (corresponding to the distance in the downstream direction from the paddle) of the temperature of the foil strip (including unsolidified fluid) during casting, and (b) shows the surface of the cooling zone. A temperature change is schematically shown. The curves in the figure show the case where (1) is a thin-walled roll (for example, 25 mm) manufactured by a thin-walled roll (conventional method, for example, 10 mm), and (2) is a thin-walled roll. (Conventional method, for example, 10 mm) represents a case where a thick foil strip (for example, 40 μm) is manufactured, and (3) is a thick-walled cooling strip (for example, 30 mm, for example) and a thick foil strip (for example, 30 mm). , 40 μm).

As shown in FIG. 7A, the curve (1) showing the temperature change of the foil strip is the time t from the melting point Tm of the alloy to the glass transition temperature Tg in the case of producing a thin foil strip with a thin roll. ₁ is sufficiently shorter than the vitrification limit time tg, and the foil strip is cooled at a cooling rate necessary for amorphization. On the other hand, (2) is a case where a thick foil strip is manufactured using the same thin roll, and the gradient of the temperature curve decreases as compared with the gradient of (1) as the glass transition temperature Tg is approached. time _{t 2} is longer than tg. That is, the cooling rate required for amorphization cannot be obtained.

On the other hand, the cooling curve in the case of producing a thick foil strip using a cooling roll having a thick cooling zone as in this embodiment is as shown in (3), and the gradient decreases near the glass transition temperature Tg. Is smaller than the condition (2). Thus, the time t ₂ that lead to the Tg because they are shorter than tg foil strip at a cooling rate necessary for the amorphization is cooled, the thick amorphous alloy foil strip is formed.

  The standard for designing the thickness 29 of the cooling zones 13a and 13b depends on the thickness of the amorphous alloy foil strip to be manufactured. Increase the thickness of the cooling zone according to the thickness of the foil strip. For example, when the thickness of the foil strip S is 45 μm or less, the thickness of the cooling zone is 30 mm, and when the thickness of the foil strip S is 45 to 60 μm, the thickness of the cooling zone is 50 mm, and the foil When the thickness of the band S is 60 to 120 μm, it is set to 100 mm. In the present specification, a cooling roll having a large thickness or simply a thickness cooling roll means a cooling roll having a cooling zone having a thickness of 25 mm or more. The conventional thin roll refers to a cooling roll having a thickness of about 10 mm or less.

  In order to help understanding of the above heat transfer behavior, description will be made with reference to FIG. FIG. 8 shows a cooling roll provided with (a) a thin cooling roll (for example, a thickness of 10 mm) and a thick foil strip (for example, a plate thickness of 40 μm), and (b) a thick cooling band (for example, a thickness of 30 mm). The transition of the cooling roll outer peripheral surface temperature at the time of producing a thick foil strip (for example, plate | board thickness 40 micrometers) is shown typically. The temperature measurement position is upstream of the paddle, for example, 20 cm from the paddle. In both (a) and (b), the initial stage of casting rises rapidly, and then the rate of temperature rise decreases, but continues to rise linearly with a constant gradient. In addition, the temperature increase rate at the initial stage of casting is lower in the thick cooling roll than in the thin cooling roll.

In addition, in the case of a thin cooling roll, the microscopic structure of the formed foil strip is amorphous up to the roll surface temperature _Taf1 , but when it exceeds that, crystallization starts. Further, when time elapses, a paddle break occurs at T _pb1 , and thereafter no foil strip is formed. The tendency is the same in the case of the thick cooling roll, but the time until the crystallization starts and the time until the paddle break occurs are significantly increased.

Further, the surface temperature T _af of the cooling roll at which crystallization _begins, and a roll surface temperature T _pb paddle break occurs are all higher towards the thick roll. _{That, T af1 <T af2, T} pb1 <T pb2, a. The reason why the cooling ability is large even when the temperature of the outer peripheral surface of the roll is high is that the thickness of the heat flows more three-dimensionally (see the arrows representing the heat flow in FIG. 9).

FIGS. 9A and 9B show the temperature distribution in the thickness direction of the cooling roll immediately below the foil strip at one point in the temperature zone where the foil strip temperature from Tm to Tg when casting the amorphous alloy foil strip. Are (a) showing a thin roll and (b) showing a thick roll. As shown to Fig.9 (a), in a thin roll, the temperature of a roll outer peripheral surface is high, and the temperature of the roll inner surface which contacts cooling water is also high. On the other hand, as shown in FIG. 9B, in the thick roll, both the outer surface temperature T _r2 and the inner surface temperature T _w2 are lower than those in the thin roll T _{r1 and} T _w2 . This is because heat diffuses widely in a three-dimensional manner in the thick roll. Since the inner surface temperature of the thick roll is lower than that of the thin roll, the amount of heat exhausted between the roll and the cooling water is Qa> Qb, and the cooling efficiency of the cooling water is lower in the thick roll. However, since the amount of heat stored in the thick part of the thick cooling zone is large, the time from the start of casting to the start of crystallization becomes long.

  In this way, the thick roll can temporarily store a large amount of heat with its own heat capacity. Most of the heat stored in the thick part of the cooling roll is transferred to the cooling water and released while the roll goes around. However, some of the heat accumulates on the chill roll, raising the roll temperature. In order to stop the exhaust heat from the cooling roll to the cooling water W, it is effective to increase the diameter and width of the roll. It is also effective to keep the temperature of the cooling water low. By taking these measures, the time for continuous casting can be increased.

  Based on this heat transfer mechanism, the heat capacity of the cooling zones 13a and 13b of the cooling roll 13 is designed. That is, it is effective to increase the heat capacities of the cooling zones 13a and 13b in order to increase the time until the crystallization starts in FIG. 8 and to increase the time until the pouring is stopped. This is nothing but increasing the thickness, diameter and width of the cooling zone.

  In the present embodiment, the diameter of the pair of cooling zones 13a and 13b is preferably 0.4 to 2.0 m. By setting the diameter of the cooling zone to 0.4 m or more, sufficient time is ensured during one rotation of the cooling zone. As a result, the heat transferred from the molten alloy to the outer peripheral surface of the cooling zone is efficiently discharged to the cooling water. On the other hand, when the diameter of the cooling zone is set to 2.0 m or less, the manufacturing apparatus 1 is prevented from being excessively large, the operation is facilitated, and the strength of the mechanical part such as the bearing of the cooling roll 13 is ensured. It becomes easy.

  Moreover, it is preferable that the width | variety of the cooling belt | band | zones 13a and 13b shall be 1.5 times or more of the width | variety of the foil strip | belt S which is going to manufacture, for example. Thereby, the heat transmitted from the molten alloy A to the cooling zones 13a and 13b spreads in the width direction, and the amount of exhaust heat to the cooling water for each rotation of the cooling roll increases.

In order to further increase the cooling efficiency of the cooling roll, the cooling water W is cooled. The temperature of the cooling water W supplied into the cooling roll 13 is preferably 20 ° C. or less, and more preferably 10 ° C. or less. This is because the lower the temperature of the cooling water, the more efficiently the cooling zones 13a and 13b can be cooled, and the thickness of the amorphous alloy foil strip that can be manufactured increases.
Further, after the solute is dissolved in the cooling water to lower the freezing point, the temperature of the cooling water W when it is supplied into the cooling roll 13 may be 0 ° C. or lower.

  In order to keep the temperature of the cooling water W supplied to the cooling roll 13 below the room temperature, a cooling means 43 such as a refrigeration system or an air conditioner is provided in the course of the cooling water W illustrated in FIG. You may install the heat pump currently used for equipment. This object can also be achieved by means of putting ice into the water storage tank 42. In addition, when the temperature of the outer peripheral surface of a cooling roll becomes lower than room temperature, there exists a possibility of dew condensation. In order to prevent dew condensation, a gas containing no moisture such as dry air or nitrogen may be sprayed on the outer peripheral surface of the cooling roll. The gas is blown before the casting starts. When casting is started, the temperature of the outer peripheral surface of the cooling roll immediately exceeds room temperature, so that it is not necessary to blow gas.

  In order to further enhance the cooling effect of the cooling water W, it is preferable to provide cooling fins 28 as shown in FIG. By increasing the contact area between the cooling zone and the cooling water, the amount of heat exhausted from the cooling water increases, and the time until casting switching can be extended.

  Furthermore, the material of the cooling zones 13a and 13b preferably has a high thermal conductivity, and is preferably a material having a higher thermal conductivity than, for example, 250 W / (m · K). 300 W / (m · K) or more is more preferable. By increasing the thickness of the cooling zones 13a and 13b, non-uniform thermal deformation of the roll, which has been a problem with conventional thin rolls, is less likely to occur, so material selection that emphasizes thermal conductivity rather than mechanical strength it can. However, materials with high thermal conductivity tend to have poor wear resistance. In order to maintain the wear resistance, it is possible to achieve both wear resistance and high thermal conductivity by applying a treatment for curing only the surface layer of the outer peripheral portion of the cooling roll. Curing of the surface layer can be realized by, for example, ion implantation. In this case, in order to prevent the generation of cracks due to thermal stress, it is preferable to provide a concentration gradient to the implanted ions.

  The forbidden band 18 interposed between the cooling bands is provided in order to make the temperature distribution in the width direction in the cooling band generated by alternate casting uniform and to suppress the influence on the formed amorphous foil band as much as possible. The material of the forbidden band 18 preferably has a lower thermal conductivity than the material of the cooling band, but may have the same thermal conductivity. In the case where the material of the forbidden band 18 is the same as the material of the cooling band, the forbidden band 18 means a thick part of the cooling roll that is interposed between the two cooling bands and the outer peripheral surface of the cooling roll does not contact the molten metal.

When the thermal conductivity of the forbidden band 18 is equal to the thermal conductivity of the cooling band, the width of the forbidden band 18 is preferably as large as possible. When the thermal conductivity is the same, the width of the forbidden band 18 is preferably at least one third of the width of the amorphous alloy foil band S. As shown in FIG. 11, when the width f of the forbidden band is less than one third of the width c of the foil band S, the thickness of the formed amorphous alloy foil band is inclined in the width direction. In FIG. 11, the thickness deviation is _a 100 fraction relative to the average thickness ta of the difference in thickness | t ₁ -t ₂ | between the thicknesses t _{1 and} t ₂ at both ends of the width of the foil strip. FIG. 11 shows a case where the width c of the foil strip is 150 mm. When the width f of the forbidden strip is 50 mm or less, that is, 1/3 or less of the width c of the foil strip, the thickness deviation increases rapidly. To do. The plate thickness is measured with a micrometer, and is an average of values measured in a region where the area near the width ends of the foil strip is 1 cm ² . If a thickness deviation occurs in the foil strip, it is not preferable because defects such as a decrease in the space factor of the core and a winding slip in the core winding process occur.

  The nozzle 15 used in the production of the amorphous alloy foil strip of the present embodiment is a slit nozzle, and the width of the slit measured in the circumferential direction of the cooling roll 13 is 0.2 to 1.2 mm. 3 to 0.8 mm. The nozzle type may be a single slit, but a multiple slit is more preferable in terms of productivity. According to experience, the plate thickness is inversely proportional to the roll peripheral speed. Therefore, in the case of a single slit nozzle, it is necessary to set the peripheral speed slower than that of the multiple slit nozzle. The peripheral speed of the cooling roll 13 is, for example, 10 to 30 m / second, for example, 15 to 25 m / second. The distance (gap) between the nozzle 15 and the outer peripheral surface of the cooling roll is, for example, 0.1 to 0.5 mm, for example, 0.15 to 0.25 mm. The discharge pressure of the molten alloy A is, for example, 10 to 40 kPa, for example, 20 to 30 kPa.

  When supply of molten alloy A (pouring) is started to one of the cooling zones, for example, the outer circumferential surface of the cooling zone 13a via the nozzle 15, the temperature of the outer circumferential surface of the cooling roll rises rapidly immediately after the start of pouring, and thereafter The ascending speed decreases and then gradually rises at a constant speed. Even if the surface temperature of the cooling roll 13 rises, for example, if it is 200 ° C. or less, the plate thickness of the foil strip is substantially constant, and the cooling rate necessary for amorphization is ensured. That is, an amorphous alloy foil strip is obtained. Here, the measurement of the temperature of the outer peripheral surface of the cooling zone is performed, for example, at the center of the width of the cooling zone, upstream of the paddle P, for example, at a position of 20 cm. For example, a contact thermometer is used to measure the outer peripheral surface temperature of the cooling roll. A specific example is described in Patent Document 3.

  The timing of switching the casting between the cooling zones can also be determined by measuring the surface temperature of the foil strip S to be formed. The measurement position is preferably an appropriate position before the foil strip S is peeled from the cooling roll. A contact-type thermometer can be used as the thermometer for measuring the surface temperature of the foil strip S, but in the case of an Fe-based alloy, an infrared radiation thermometer can also be used. Monitoring the temperature of the foil strip S is a more direct means for determining the amorphous nature of the foil strip during casting. A method of monitoring the temperature of the outer peripheral surface of the cooling zone at a predetermined position can also be adopted. If the apparatus is the same, it is possible to set the casting switching time with a casting time that provides a good foil strip. If the amorphous alloy foil strips to be manufactured have the same size (plate thickness, width), alloy composition, etc., it is possible to switch based on the time measured in advance.

Next, the effect of this embodiment will be described.
In the present embodiment, the cooling roll 13 of the amorphous alloy foil strip manufacturing apparatus 1 is provided with two cooling strips 13a and 13b, and the foil strip S is cast by using them alternately. Thereby, about one cooling zone, casting and cooling will be repeated and roll temperature can be suppressed below to a predetermined value. As a result, an amorphous alloy foil strip having a large plate thickness can be produced on an industrial scale. Such an amorphous alloy foil strip can be used as, for example, a power transformer and a motor core. It can also be used as a magnetic shield material.

  Further, in the present embodiment, the cooling zone 13a and the cooling zone 13b are spaced apart from each other, a forbidden zone 18 having a predetermined width is interposed between the cooling zones, and molten alloy is supplied to the forbidden zone 18 By not doing so, the cooling zone 13a and the cooling zone 13b can be thermally independent from each other. Thereby, while ensuring a cooling rate, a thick foil strip can be manufactured with high productivity, and the temperature of the other cooling zone is prevented from being inclined in the width direction due to the presence of one cooling zone, and the thickness of the foil strip is reduced. A deviation can be prevented from occurring.

  Further, in the present embodiment, since a multi-slit nozzle is used as the nozzle 15, the plate thickness of the foil strip S can be made uniform and the occurrence of pinholes can be reduced. The surface properties of the foil strips S are microscopically disturbed due to minute vibrations of the paddle P and local defects of the cooling roll 13, and when the disturbance is large, fish scale-like striped patterns and pinholes called fish scales are observed. Is formed on the foil strip S and can be observed with the naked eye. When the multi-slit nozzle method is used, these defects formed in the fluid layer drawn out from the upstream paddle are compensated by the downstream paddle, so that the foil strip S having a good surface property and very few pinholes. Can be manufactured.

As described above, the surface of the amorphous alloy foil strip produced by the multiple slit nozzle method is smooth and has very few pinholes. The number density of pinholes in the foil strip is, for example, 25 pieces / m ² or less, for example, 10 pieces / m ² or less, for example, none. The space factor when foil strips are laminated is improved by reducing pinholes and smoothing the surface. For example, in the present embodiment, when a strip having a thickness of 33 μm or more is manufactured and a wound iron core is manufactured using this foil strip, the space factor is 80% or more, and a foil strip having a thickness of 40 μm or more is manufactured. And if an iron core is produced with this foil strip, the space factor will be 85% or more. For example, when the plate thickness is 45 μm or more, the space factor is 90% or more. For example, in the case of a foil strip of 50 μm or more, the space factor is 93% or more. A foil strip having a smooth surface and few pinholes is preferable as an electromagnetic iron core material because it has a small hysteresis loss because there are few obstacles to domain wall movement. Further increasing the space factor has the same significance as increasing the saturation magnetic flux density Bs. For example, increasing the space factor from 80% to 90% is practically the same as increasing Bs from 1.60T to 1.78T.

  Moreover, in this embodiment, since a cooling zone with a large thickness is used, various problems due to non-uniform thermal deformation of the roll, which often occurs with conventional thin rolls, are solved. For example, local embrittlement of the foil strip S due to uneven cooling of the foil strip and variations in magnetic properties do not occur.

  The present invention has been described above with reference to the embodiment. However, the present invention is not limited to this embodiment. For example, as long as a person skilled in the art appropriately adds, deletes, or changes a design, or adds, omits, or changes a process in the above-described embodiment, the gist of the present invention is included. And within the scope of the present invention.

For example, a cooling roll having a pair of cooling zones, a combination of a conventional cooling roll having a single cooling zone and the cooling roll of the present invention, an apparatus and a method for supplying molten alloy to these three or more cooling zones sequentially Are also included within the scope of the present invention.
Also for the molten metal supply means, a tundish having a plurality of nozzles facing the outer peripheral surface of the cooling zone can be used. Further, a chill roll having three or more cooling zones has the same technical idea and is included in the scope of the present invention.
By increasing the cooling zone, it is possible to increase the limit thickness of the foil strip that can be manufactured. Although the limit sheet thickness was 25 μm in the conventional cooling roll of the single cooling zone, the thick amorphous alloy foil strip of 50 μm for two, 75 μm for three, and 100 μm for four is manufactured almost continuously. it can.

It is a front view which illustrates the manufacturing apparatus of the amorphous alloy foil strip which concerns on embodiment of this invention. It is sectional drawing which illustrates the structure of the cooling roll in FIG. It is sectional drawing which illustrates the part which a molten alloy contacts with a cooling roll in FIG. It is a conceptual diagram which illustrates the path | route of the cooling water which cools a cooling roll in FIG. It is a timing chart which illustrates the manufacturing method of the amorphous alloy foil strip concerning this embodiment, taking time on a horizontal axis and taking a cooling zone on a vertical axis. It is a ternary composition diagram illustrating the composition of the iron-based amorphous alloy foil strip produced in this embodiment. (A) is a schematic diagram which illustrates the time change of the foil strip temperature during casting, (b) is a schematic diagram which illustrates the time change of the roll outer peripheral surface temperature during casting. It is a schematic diagram which compares the time change of the roll surface temperature during casting a thick foil strip with (a) when a thin roll is used, and (b) when using a thick roll. (A) And (b) is a schematic diagram which illustrates the temperature change of the cooling roll thickness direction during amorphous alloy foil strip casting, (a) shows a thin roll, (b) is a thick roll. Indicates. It is sectional drawing of the water channel which illustrates the cooling fin provided in the inner surface which contact | connects the cooling water of a cooling zone. It is a graph which illustrates the influence of the width | variety of a forbidden band on the board thickness knitting difference of an amorphous foil strip.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus, 11 Drive means, 12a, 12b Rotating shaft member, 13 Cooling roll, 13a, 13b Cooling zone, 14 Crucible, 15 Nozzle, 16 Moving means, 17a, 17b Slit, 18 Forbidden zone, 24 Water channel, 25 Water supply pipe , 26 Drain pipe, 28 Cooling fin, 29 Thickness of cooling zone, 31 Support mechanism, 32 Center portion, 41a, 41b Bearing, 42 Water storage tank, 43 Cooling means, A Alloy molten metal, P paddle, R region, S foil strip , W Cooling water

Claims (11)

A cooling roll;
Drive means for rotating the cooling roll;
Supply means for supplying molten alloy to the outer peripheral surface of the cooling roll;
With
In the axial direction of the cooling roll from the first cooling zone, the supply means constitutes a part of the outer peripheral portion of the cooling roll and circulates along the circumferential direction of the cooling roll. An apparatus for producing an amorphous alloy foil strip, wherein the molten alloy is alternately supplied to a second cooling zone that is spaced apart from the forbidden zone and circulates along the circumferential direction of the cooling roll. .   2. The apparatus for producing an amorphous alloy foil strip according to claim 1, wherein the cooling roll is a water-cooling roll in which cooling water flows.   The apparatus for producing an amorphous alloy foil strip according to claim 2, further comprising means for cooling the cooling water.   The width of the forbidden band is not less than one third of the width of the amorphous alloy foil band in the axial direction of the cooling roll. Equipment for producing crystalline alloy foil strips.   5. The amorphous alloy foil strip according to claim 1, wherein the supply unit includes a nozzle in which a plurality of slits are arranged along a circumferential direction of the cooling roll. Manufacturing equipment. A first step of supplying molten alloy to a first cooling zone that constitutes a part of the outer peripheral portion of the cooling roll and rotates around the circumferential direction of the cooling roll while rotating the cooling roll;
While rotating the cooling roll, the first cooling zone is separated from the first cooling zone with a forbidden band in the axial direction of the cooling roll, and the second cooling zone that circulates along the circumferential direction of the cooling roll A second step of supplying molten alloy;
With
The method for producing an amorphous alloy foil strip, wherein the first step and the second step are alternately performed.   The method for producing an amorphous alloy foil strip according to claim 6, wherein the thickness of the amorphous alloy foil strip is 30 µm or more.   The composition of the molten alloy has an iron content of 70 to 81 atomic%, a silicon content of 3 to 17 atomic%, a boron content of 9 to 23 atomic%, and a glass transition point. The method for producing an amorphous alloy foil strip according to claim 6 or 7, wherein the composition is such that the temperature is 500 ° C or higher.   The composition of the molten alloy has an iron content of 70 to 81 atomic%, a silicon content of 1 to 17 atomic%, a boron content of 7 to 23 atomic%, and a carbon content. The method for producing an amorphous alloy foil strip according to claim 6 or 7, wherein the composition is such that the glass transition point is 500 ° C or higher.   The method for producing an amorphous alloy foil strip according to claim 8 or 9, wherein the molten alloy contains 0.01 to 1.0% by mass of tin. 11. The method for producing an amorphous alloy foil strip according to claim 6, wherein the number density of pinholes in the amorphous alloy foil strip is 25 pieces / m ² or less.

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