JPH09271909A - Cooling base board for producing quenched metal thin strip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of air pocket and to uniformize and improve magnetic characteristic and mechanical characteristic of a metal thin strip by forming V-shaped grooves on the surface of a cooling base board (roll) used for producing the metal thin strip. SOLUTION: V-shaped grooves are formed on the surface of the moving cooling base board and constituted so as to direct the closed direction of these grooves to the moving direction (the arrow mark) of the cooling base board. By this constitution, atmospheric gas entrapped between molten metal and the cooling base board is efficiently ejected to the side direction of a paddle and the generation of the air pocket is prevented and cooling speed of the thin strip can be quickened. In this case, the angle θ of the V-shaped grooves is >0 deg. to <90 deg. angle to the upstream direction, desirably 20-70 deg. by using the moving axis of the cooling base board as a reference. further, the V grooves can be arranged at the different angle in the right and left sides, such as the figure (b), to the shifting axis of the cooling base board passing the closed part, but in this case, the difference of the θs at the right and the left sides is within ±10 deg. to stabilize the paddle.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a power transformer,
The present invention relates to a device member for producing a quenched metal ribbon used for an iron core material such as a high frequency transformer.

[0002]

2. Description of the Related Art As a method for continuously producing a ribbon by rapidly cooling an alloy from a molten state, a centrifugal quenching method,
A single roll method, a twin roll method, etc. are known. In these methods, molten metal is jetted from an orifice or the like onto an inner peripheral surface or an outer peripheral surface of a metal drum rotating at high speed to rapidly solidify the molten metal to produce a ribbon or a wire. Furthermore, by properly selecting the alloy composition, an amorphous alloy similar to liquid metal can be obtained,
A material having excellent magnetic properties or mechanical properties can be manufactured.

These quenched metal ribbons are manufactured by bringing the molten metal into contact with a cooling substrate and rapidly removing the heat from the molten metal to solidify the molten metal as described above. Therefore, in order to quench efficiently and efficiently, it is important to improve the adhesion between the molten metal and the cooling substrate. However, in reality, the atmospheric gas is trapped between the molten metal and the cooling substrate, and a hollow called an air pocket is generated on the thin strip surface that contacts the cooling substrate. The air pocket portion is a portion where the ribbon is not in contact with the cooling substrate, and therefore, the cooling rate is slower than the portion where the ribbon is in contact with the cooling substrate. As a result, crystallization occurs in the air pockets, deteriorating the magnetic properties or mechanical properties.

In order to reduce air pockets, carbon monoxide and oxygen can be moved at a predetermined ratio and burned in the vicinity of a paddle (a pool of water) on a cooling body to create a casting atmosphere with a low density reducing flame atmosphere near the paddle. Is disclosed (Japanese Patent Publication No. 1-501924). But,
This method not only complicates the equipment, but also increases the manufacturing cost. Further, since carbon monoxide is used, there is a problem in operational safety.

Further, in order to reduce scratches and cracks on the surface of the ribbon, the surface of the cooling body has irregularities of micron order or less by buffing (Japanese Patent Laid-Open No. 166059/1987) and roughness of the free surface of the ribbon. In order to reduce the surface roughness of the cooling roll by polishing with abrasive paper of abrasive grain No. 600 to No. 1000 (Japanese Patent Laid-Open No. 4-288952), for the purpose of subdividing the magnetic domain of the ribbon, A cooling body having scratches on the surface of the cooling roll obliquely to the direction of rotation and a ribbon produced by the cooling body (JP-A-60-72648).
Gazette), etc. However, none of these known examples mention air pockets.

[0006]

Conventionally, as a method for reducing air pockets, there is no simple equipment, and it is possible to reduce air pockets even with a cooling substrate whose surface shape is controlled, which is simple equipment. No longer possible. The present invention, even if air is trapped between the paddle and the molten metal, is efficiently discharged to easily reduce the air pockets in the ribbon, and efficiently maintain the contact between the cooling substrate and the molten metal. An object of the present invention is to provide a cooling substrate for producing a quenched metal ribbon, which can obtain a ribbon having excellent characteristics.

[0007]

The present invention is as described below. In a device for producing a quenched metal ribbon by jetting a molten metal onto a moving cooling substrate through a pouring nozzle having a slit-shaped opening, a V-shaped groove is formed on the surface of the cooling substrate. And a closed direction of the V-shaped groove is oriented in the moving direction of the cooling substrate.

Hereinafter, the present invention will be described in detail. As shown in FIG. 2, the air pocket is formed by the atmospheric gas (air) caught in the paddle 2 from the upstream side being expanded by the heat of the molten metal and solidified as it is.
A conventional cooling substrate has a groove formed by polishing in a direction parallel to the rotation direction of the cooling substrate, and the air caught in the paddle moves so as to be pushed out to the upstream side of the paddle. However, since new air continuously enters from the upstream side, it becomes difficult for the air to escape to the upstream side through the concave groove.

Unlike the conventional groove portion, the present invention forms the V-shaped groove on the cooling substrate as shown in FIG. 1 so that the air is efficiently discharged to the side surface instead of the upstream side of the paddle. However, various experiments were repeated with the aim of reducing the number of air pockets, and they were completed. The point of the present invention is to discharge the air that has been once caught from the side surface of the paddle where the air is not caught.
This made it possible to easily remove the air.
Similar effects were expected in a conventional cooling body having scratches obliquely to the rotation direction of the cooling roll, but when actually tested, the air pockets could not be reduced. This is because the trapped air became rather unstable as a result of the trapped air being discharged to only one side surface of the paddle.

In the present invention, the V-shaped groove is shown in FIG.
As shown in (b) and (c), they are arranged so as to be closed in the moving direction of the cooling substrate. With this arrangement, the air is efficiently discharged in the paddle side surface direction.
When the V-shaped groove is arranged so as to open with respect to the moving direction of the cooling substrate, the extruded air gathers in the central portion in the width direction of the ribbon, so that the air is not discharged and it is the same as the conventional case. Air pockets do not decrease. In order to increase the productivity, the cooling substrate having the form shown in FIG. 1 (c) may be used.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A cooling substrate for producing a quenched metal ribbon according to the present invention will be described. The material of the cooling substrate is preferably one having a high thermal conductivity. For example, Cu, Cu alloy, Fe alloy, or those obtained by plating them with Cr are suitable. As a cooling substrate, a roll method such as a single roll method or a twin roll method is suitable because a ribbon can be stably manufactured, but the belt method can also obtain the effect of the present invention.

The V-shaped groove on the cooling substrate is shown in FIG.
As shown in (b) and (c), they are arranged so as to be closed in the moving direction of the cooling substrate. The groove angle θ is shown in FIG.
As shown in (d), the angle formed with the upstream direction with respect to the movement axis of the cooling substrate is more than 0 ° and less than 90 °. In order for air to be discharged efficiently and to obtain a greater effect,
The angle is preferably 20 ° to 70 °. Further, the groove is shown in FIG. 1 with respect to the moving axis of the cooling substrate passing through the V-shaped closed portion.
It may be arranged at right and left different angles as shown in (b).
In that case, in order to stabilize the paddle, it is desirable that the difference between the left and right θ be within ± 10 °. The closed apex portion of the V-shaped groove may be within the range of the ribbon width, but it is more preferably near the center in the ribbon width direction.

The opening width of the groove is preferably about 0.1 to 50 μm. If it is smaller than about 0.1 μm, the air does not move efficiently in the groove, and if it is larger than about 50 μm, the molten metal has a high probability of entering the groove, which hinders the movement of the air. The grooves are preferably continuous. By the continuous groove,
This is because the air is efficiently discharged. The depth of the groove is 1
It may be about 0 μm or more. This is because if it is smaller than about 10 μm, the air does not move efficiently in the groove.

The closed apex portion of the V-shaped groove may have an intersection of about 1 mm or less. Air moving from the downstream side gathers at the intersection, but since it is connected to the V-shaped groove, the air does not stay. To obtain a greater effect, it is preferable that the intersection is completely closed. The distance (pitch) between the grooves may be about 200 μm or less. This is because the entrained air cannot be efficiently discharged if the pitch is larger than about 200 μm. The groove of the cooling substrate can be formed by mechanical grinding, a rotating brush, a stamp or the like. Also, these methods can be performed online.

[0015]

EXAMPLES The present invention will be further described below based on Examples and Comparative Examples. Example 1 A cooling roll having an V-shaped groove according to the present invention (having an outer diameter of 5
A thin strip was manufactured by a single roll method using an 80 mm Cu cooling roll). The cooling roll had a V-shaped groove formed by mechanical grinding after the roll surface was once polished to a mirror surface. This groove has an angle formed with the upstream direction of 45 degrees on both sides with respect to the movement axis of the cooling roll passing through the V-shaped closed portion.
The groove has an opening width of 30 μm and a groove depth of 1 °.
The groove pitch was 6 μm and the groove pitch was 130 μm.

Comparative Example 1 As Comparative Example 1, a ribbon was manufactured by a single roll method using a cooling roll (Cu cooling roll having an outer diameter of 580 mm) which was polished by ordinary emery paper. This cooling roll uses No. 600 emery paper and has polishing grooves parallel to the moving direction of the cooling roll.

Comparative Example 2 In Comparative Example 2, a cooling roll (having an outer diameter of 580 mm) having V-shaped grooves opened in the moving direction of the cooling substrate, which is the reverse of the direction of the V-shaped grooves of the present invention, is arranged. A thin strip was produced by a single roll method using a Cu cooling roll). Similar to the cooling roll of Example 1 of the present invention, this cooling roll had a V-shaped groove formed by mechanical grinding after the roll surface was once polished to a mirror surface. This groove has an angle of 120 ° to the left and right with the upstream direction with respect to the axis of movement of the cooling roll passing through the V-shaped closed portion, the groove opening width is 30 μm, and the groove depth is The groove pitch was 16 μm and the groove pitch was 130 μm.

The thin film alloys of the present invention material and the comparative materials 1 and 2 all have a composition of Fe80.5Si6.5B12Cl.
(Atomic%). 750 g of this mother alloy was loaded into a quartz crucible and subjected to high frequency melting, and then a molten metal was ejected from a nozzle having a slit-shaped opening portion onto the cooling roll rotating at a high peripheral speed of 24 m / sec to obtain a ribbon. The nozzle used is a single slit nozzle (width 0.4 mm, length 25 mm). Each of the obtained ribbons has a width of 25 mm and a plate thickness of 2
There is 7 μm.

The cooling roll contact surface (roll surface) of the ribbon was photographed with a light microscope and the area ratio of air pockets was examined using an image processing apparatus. In addition, this thin strip at 360 ℃ for 1 hour,
Magnetic field annealing was performed in a nitrogen atmosphere, and magnetic properties were measured by SST. Table 1 shows the results.

[0020]

[Table 1]

The area ratio of the air pockets is 21% for the thin strip of Comparative Material 1 and 25% for the thin strip of Comparative Material 2.
The ribbon produced by the cooling roll of the present invention was 10%.
A large air pocket was observed at a position corresponding to the closed portion of the V-shaped groove by the optical microscope observation of the comparative material 2.
Further, the iron loss value of each ribbon is W13 / 50 for Comparative Material 1.
(Magnetic flux density of 1.3 T, iron loss value at 50 Hz) of 0.
14 W / kg, Comparative material 2 was 0.16 W / kg, whereas the material of the present invention was 0.10 W / kg. As these results show, the cooling substrate of the present invention reduces the air pockets in the ribbon, thereby improving the magnetic properties of the ribbon.

[0022]

According to the present invention, the cooling rate of the ribbon can be easily increased without using a complicated atmosphere gas device or auxiliary cooling roll, and the characteristics of the ribbon can be improved. At the same time, the manufacturing cost can be reduced because a complicated atmosphere gas device and equipment such as auxiliary cooling rolls are not required. Further, since a large cooling effect can be obtained regardless of the component system and the thickness of the thin strip, the application range is wide.
Further, by reducing the air pockets, it is possible to obtain a thin strip having small surface irregularities and good surface properties. This also leads to an improvement in the space factor when using a wound iron core or a laminated iron core.

[Brief description of drawings]

FIG. 1 is a schematic view showing a pattern of a cooling substrate and a V-shaped groove of the present invention, FIG. 1A shows an example in which the V-shaped groove is symmetrical with respect to a moving axis of the cooling substrate, and FIG. ) Shows an example in which the V-shaped groove has different left and right angles with respect to the movement axis of the cooling substrate, and (c) shows an example in which two kinds of ribbons are manufactured at the same time. , (D) show the definition of the groove angle θ.

2A and 2B are explanatory views showing a principle of forming an air pocket in thin ribbon manufacturing, wherein FIG. 2A is a schematic view seen from above a cooling substrate, and FIG. 2B is a schematic view seen from a side surface of the cooling substrate. Is.

[Explanation of symbols]

 1 Cooling board 2 Paddle 3 Molten metal 4 Nozzle 5 Thin strip

Claims (1)

[Claims] Claim: What is claimed is: 1. An apparatus for producing a rapidly cooled metal ribbon by ejecting molten metal onto a moving cooling substrate through a pouring nozzle having a slit-shaped opening and rapidly solidifying the molten metal on the surface of the cooling substrate. A cooling substrate for producing a quenched metal ribbon, comprising a V-shaped groove, and the closed direction of the V-shaped groove is oriented in the moving direction of the cooling substrate.