阅读说明：本技术 非晶质金属薄片、层叠芯及非晶质金属薄带的冲裁加工方法 (Amorphous metal sheet, laminated core, and method for punching amorphous metal ribbon ) 是由 太田元基 于 2020-02-13 设计创作，主要内容包括：本发明提供非晶质金属薄带的冲裁加工性良好的冲裁加工方法以及由此制造的非晶质金属薄片和层叠芯。作为非晶质金属薄片,金属薄片的厚度大于30μm且为50μm以下,上述金属薄片具有由至少观察到塌边、剪切面和断裂面的冲裁加工面构成的侧面,并且,在上述侧面,塌边的宽度相对于金属薄片的厚度为30％以下。(The invention provides a punching method with good punching processability of an amorphous metal thin strip, and an amorphous metal thin strip and a laminated core manufactured by the method. The amorphous metal sheet has a thickness of more than 30 [ mu ] m and 50 [ mu ] m or less, and has a side face comprising a punched surface on which at least a sag, a shear surface and a fracture surface are observed, and the width of the sag is 30% or less with respect to the thickness of the metal sheet on the side face.)

1. An amorphous metal thin sheet is provided, which comprises a base,

the thickness of the metal sheet is more than 30 μm and less than 50 μm,

the metal sheet has a side surface formed by a punched surface on which at least a sagging, a shear surface, and a fracture surface are observed, and the width of the sagging is 30% or less with respect to the thickness of the metal sheet in the side surface.

2. The amorphous metal flake of claim 1, wherein the width of the sag is 8 μ ι η or less.

3. The amorphous metal flake of claim 1 or 2, wherein the amorphous metal flake is comprised of an alloy composition represented by the general formula: fe_100-a-b-c-dB_aSi_bC_cM_dExpressed that M is at least one element of Al, Sn, Cr, Mn, Ni, Cu, a, b, c and d satisfy, in atomic%, 7. ltoreq. a.ltoreq.20, 1. ltoreq. b.ltoreq.19, 0. ltoreq. c.ltoreq.4, 0. ltoreq. d.ltoreq.2.

4. The amorphous metal flake of claim 3, wherein 0.03. ltoreq. d.ltoreq.2.

5. A laminated core obtained by laminating the amorphous metal sheets according to any one of claims 1 to 4.

6. A method for punching an amorphous metal ribbon, wherein the amorphous metal ribbon is an amorphous metal ribbon having a thickness of more than 30 [ mu ] m and 50 [ mu ] m or less, and the side surface of the amorphous metal ribbon formed by punching the amorphous metal ribbon is a punched surface on which at least sag, shear plane, and fracture plane are observed, and punching is performed so that the width of the sag is 30% or less with respect to the thickness of the metal ribbon on the side surface.

7. The method of blanking an amorphous metal ribbon as claimed in claim 6, wherein the blanking process is performed in a manner such that the amorphous metal ribbon is cut outAs the amorphous metal ribbon, an amorphous metal ribbon composed of an alloy composition represented by the general formula: fe_100-a-b-c-dB_aSi_bC_cM_dExpressed that M is at least one element of Al, Sn, Cr, Mn, Ni, Cu, a, b, c and d satisfy, in atomic%, 7. ltoreq. a.ltoreq.20, 1. ltoreq. b.ltoreq.19, 0. ltoreq. c.ltoreq.4, 0. ltoreq. d.ltoreq.2.

8. The method of blanking an amorphous metal ribbon as recited in claim 7, wherein d is 0.03. ltoreq. d.ltoreq.2.

9. The method for blanking the amorphous metal ribbon as claimed in any one of claims 6 to 8, wherein a blanking die including a punch and a die is used.

Technical Field

The present invention relates to an amorphous metal sheet used as a laminated core for motors, antennas, and the like, a laminated core, and a method for punching an amorphous metal ribbon.

Background

From the world, the power consumption of the motor is considered to be about half of the total power consumption. The loss of electric power in the motor is roughly classified into a core loss, a copper loss, and a mechanical loss in the motor core. When only the core loss is considered, a material is required to have good soft magnetic characteristics.

At present, the main soft magnetic material used for the motor core is a non-oriented electrical steel sheet. However, in recent years, an amorphous metal ribbon having very good soft magnetic properties as compared with a non-oriented electrical steel sheet has attracted attention, and has been put to practical use in limited applications. It is clear that if the application range of the amorphous metal ribbon is expanded, it contributes to suppression of global power consumption, and expansion of the use thereof is expected. In addition, the motor core uses a laminated core obtained by processing a non-oriented electromagnetic steel sheet or an amorphous metal ribbon into a predetermined shape and laminating the processed sheet or ribbon. There are many methods of machining, but in order to obtain a motor core having a complicated shape, there is a punching process which can be machined along the shape and requires a short machining time.

In addition, a thin strip of 30 μm or less is generally used as the amorphous metal strip. The thickness is about 1/5-1/20 relative to the thickness of the non-oriented electromagnetic steel plate. That is, when the core is made of an amorphous metal ribbon, the number of layers increases, and the number of punching processes increases accordingly.

For example, japanese patent application laid-open No. 2008-213410 and international publication No. 2018/155206 disclose laminating an amorphous metal ribbon and punching the laminate. In any of the known documents, punching is performed after lamination, and therefore the number of punching is reduced.

Further, japanese patent application laid-open No. 2008-213410 discloses the following: a laminated plate is produced by laminating a plurality of soft magnetic metal strips having a thickness of 8-35 [ mu ] m, wherein the thickness of each thermosetting resin between the metal strips is 0.5 [ mu ] m or more and 2.5 [ mu ] m or less, and the total thickness of the laminated plate is 50 [ mu ] m or more and 250 [ mu ] m or less, and the laminated plate is subjected to punching.

Further, international publication No. 2018/155206 discloses a method for manufacturing a laminated member, the method including: a fixing step of fixing a part of the layers of the stacked amorphous metal ribbons to each other; and a punching step of punching the laminated member by cutting the laminated amorphous metal thin strip group except for the fixed fixing portion. Wherein the thickness of the amorphous metal ribbon is 10 to 60 μm.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2008-213410

Patent document 2: international publication No. 2018/155206

Disclosure of Invention

Problems to be solved by the invention

However, the application of the amorphous metal ribbon to the motor core has not been realized in mass production. One reason for this is that the amorphous metal ribbon has a high hardness. The vickers hardness of the amorphous metal ribbon is, for example, about 700HV to 950HV in the case of an Fe-based alloy composition. This value is a significantly high value in Fe-based alloys. Therefore, the machining is difficult.

As one of the processing methods of the amorphous metal ribbon, there is a method of cutting (シャー cutting) a workpiece by a cutter or a similar tool. The amorphous metal ribbon can be cut by a shear to be relatively easily processed. However, the cutting process by the shear is limited to a relatively simple shape, and is difficult to apply to a complicated shape such as a motor core.

Therefore, in the manufacture of the motor core, the application of the blanking process still has to be studied. However, when the punching process is repeated for the amorphous metal ribbon, the hardness is high, and thus the loss of the punching die is serious. When the amorphous metal thin strip is punched out one by one using the same die, the number of times of continuous use of the die that can be punched out is only about 1 ten thousand to 2 ten thousand at most. If punching is performed in a state where a plurality of amorphous metal thin strips are stacked, the number of continuous use is reduced.

If the die has such durability, the die cost will increase in the manufacturing cost of the motor core in which punched amorphous metal sheets are laminated, and the die cost will not match the cost of the motor core required in the market. In order to apply the amorphous metal ribbon to the motor core, some means for improving the punching workability is required.

That is, an object of the present disclosure is to provide a punching method having excellent punching workability of an amorphous metal ribbon, and an amorphous metal sheet and a laminated core produced thereby.

Means for solving the problems

The means for solving the above problems include the following means.

<1> an amorphous metal flake,

the thickness of the metal sheet is more than 30 μm and less than 50 μm,

the metal sheet has a side surface formed by a punched surface on which at least a sagging, a shear surface, and a fracture surface are observed, and the width of the sagging is 30% or less with respect to the thickness of the metal sheet in the side surface.

<2> the amorphous metal flake according to <1>, wherein the width of the sag is 8 μm or less.

<3>According to<1>Or<2>The amorphous metal flake, wherein the amorphous metal flake is composed of an alloy composition represented by the general formula: fe_100-a-b-c-dB_aSi_bC_cM_dExpressed that M is at least one element of Al, Sn, Cr, Mn, Ni, Cu, a, b, c and d satisfy, in atomic%, 7. ltoreq. a.ltoreq.20, 1. ltoreq. b.ltoreq.19, 0. ltoreq. c.ltoreq.4, 0. ltoreq. d.ltoreq.2.

<4> the amorphous metal flake according to <3>, wherein d is 0.03. ltoreq. d.ltoreq.2.

<5> a laminated core obtained by laminating the amorphous metal sheets <1> to <4 >.

[ claim 6 ] A method for punching an amorphous metal ribbon, wherein an amorphous metal ribbon having a thickness of more than 30 [ mu ] m and 50 [ mu ] m or less is used as the amorphous metal ribbon, wherein a side surface of the amorphous metal ribbon formed by punching the amorphous metal ribbon is formed by a punched surface on which at least sag, shear plane, and fracture plane are observed, and punching is performed so that the width of the sag is 30% or less of the thickness of the metal ribbon on the side surface.

<7>According to<6>The method for punching an amorphous metal ribbon, wherein an amorphous metal ribbon composed of an alloy composition represented by the general formula: fe_100-a-b-c-dB_aSi_bC_cM_dExpressed that M is at least one element of Al, Sn, Cr, Mn, Ni, Cu, a, b, c and d satisfy, in atomic%, 7. ltoreq. a.ltoreq.20, 1. ltoreq. b.ltoreq.19, 0. ltoreq. c.ltoreq.4, 0. ltoreq. d.ltoreq.2.

<8> the method for blanking an amorphous metal ribbon <7>, wherein d is 0.03. ltoreq. d.ltoreq.2.

<9> the method for blanking an amorphous metal thin strip according to any one of <6> to <8>, wherein a blanking die including a punch and a die is used.

Effects of the invention

According to the present disclosure, a punching method capable of improving punching workability of an amorphous metal thin strip can be provided. This enables the production of an amorphous metal sheet that has been subjected to punching at a low production cost. Further, by forming a laminated core using the amorphous metal thin sheet, application of the amorphous metal thin sheet to a motor core can be promoted.

Drawings

Fig. 1 is a graph showing a relationship between the thickness of an amorphous metal flake and a sag.

Fig. 2 is a photograph of a punched surface of an amorphous metal sheet obtained by punching.

FIG. 3 is a schematic view of FIG. 2.

FIG. 4 is a schematic view for explaining a punched surface for forming a thin strip.

Detailed Description

Hereinafter, the present invention will be described in more detail with reference to embodiments, but the present invention is not limited to these embodiments.

Conventionally, the thickness of the amorphous metal ribbon and the ease of punching have not been sufficiently studied. For example, although punching is described in the above-mentioned japanese patent laid-open publication No. 2008-213410 and international publication No. 2018/155206, the above-mentioned japanese patent laid-open publication No. 2008-213410 exemplifies an amorphous metal ribbon having a thickness of 8 to 35 μm as an amorphous metal ribbon that can be used, and the above-mentioned international publication No. 2018/155206 exemplifies an amorphous metal ribbon having a thickness of 10 to 60 μm. Further, in the example of Japanese patent laid-open No. 2008-213410, a metal ribbon with a thickness of about 25 μm, a metal ribbon with a thickness of about 12 μm, and a metal ribbon with a thickness of about 18 μm were used, and International publication No. 2018/155206 describes that the thickness is 25 μm in the column of the background art.

The present inventors have found that punching can be easily performed by setting the thickness of the amorphous metal ribbon to a predetermined range.

That is, one embodiment of the present disclosure is a method for punching an amorphous metal ribbon, in which an amorphous metal ribbon having a thickness of more than 30 μm and 50 μm or less is used as the amorphous metal ribbon. This can improve the punching workability of the amorphous metal thin strip.

According to the present disclosure, in the punching process, the punching process using the punching die composed of the punch and the die can be performed. In this case, the punch may be used as the punching die on the movable side, the die may be used as the punching die on the fixed side, and the die may be used as the punching die on the movable side. According to the present disclosure, a good punched surface can be obtained even if the clearance between the punch and the die is wide. Further, according to the present disclosure, since resistance to the bending moment of the amorphous metal ribbon can be increased, retraction of the amorphous metal ribbon is suppressed, the punch and the punching blade can easily enter, and punching can be performed with less deformation (sag).

In addition, the amorphous metal foil according to another embodiment of the present disclosure obtained by the above processing method is an amorphous metal foil, the thickness of the metal foil is more than 30 μm and 50 μm or less, the metal foil has a side face composed of a punched surface in which at least a sag, a shear surface, and a fracture surface are observed, and the width of the sag is 30% or less with respect to the thickness of the metal foil at the side face.

The thickness of the amorphous metal ribbon is the same as that of an amorphous metal thin sheet obtained by punching the amorphous metal ribbon.

As described above, in the embodiment of the present disclosure, the width of the sag in the punched surface of the amorphous metal sheet can be reduced. The width of the sag is preferably 8 μm or less, more preferably 7 μm or less, further preferably 6 μm or less, and further preferably less than 6 μm.

Hereinafter, embodiments of the present disclosure will be described in further detail. However, the scope of the claims of the present invention is not limited to the embodiment.

< amorphous Metal ribbon >

In the embodiments of the present disclosure, an amorphous metal ribbon is used.

For the amorphous metal ribbon, an amorphous metal material such as an Fe-based or Co-based material can be used. The amorphous metal material also includes a metal material capable of nano-crystallization. The amorphous metal material is a soft magnetic metal material.

Examples of the Fe-based amorphous metal material include Fe-semi-metallic amorphous metal materials such as Fe-Si-B, Fe-B, and Fe-P-C, Fe-transition metal amorphous metal materials such as Fe-Zr, Fe-Hf, and Fe-Ti, and examples of the Co-based amorphous metal material include amorphous metal materials such as Co-Si-B and Co-B.

Examples of the metal material capable of nano-crystallization include Fe-Si-B-Cu-Nb system, Fe-Zr-B- (Cu) system, Fe-Zr-Nb-B- (Cu) system, Fe-Zr-P- (Cu) system, Fe-Zr-Nb-P- (Cu) system, Fe-Ta-C system, Fe-Al-Si-Nb-B system, Fe-Al-Si-Ni-Nb-B system, Fe-Al-Nb-B system, and Co-Ta-C system.

The amorphous metal ribbon is particularly preferably composed of an alloy composition represented by the general formula: fe_100-a-b-c-dB_aSi_bC_cM_dExpressed that M is at least one element of Al, Sn, Cr, Mn, Ni, Cu, a, b, c and d satisfy, in atomic%, 7. ltoreq. a.ltoreq.20, 1. ltoreq. b.ltoreq.19, 0. ltoreq. c.ltoreq.4, 0. ltoreq. d.ltoreq.2. More preferably 75. ltoreq. 100-a-b-c-d.

The alloy composition represented by the above general formula is allowed to contain inevitable impurities. The inevitable impurities are optional components, and for example, the inevitable impurities such as S, P are allowed to be substituted with Fe within a range of 1 atomic% or less.

The alloy composition represented by the above general formula will be described in more detail below.

Both Si and B are amorphous forming elements. When Si is 1 atomic% or more, the amorphous form can be stably formed by rapid cooling. At least a part of Si is dissolved in alpha-Fe by heat treatment to form Fe₃Silicide such as Si. If Si is more than 19 atomic%, the saturation magnetic flux density Bs decreases.

It is also known that Si in α -Fe crystal grains of a bcc structure affects induced magnetic anisotropy of an Fe-based ferromagnetic material, and if Si is 3.5 atomic% or more, it is preferable to perform heat treatment in a magnetic field to incline a B-H curve and improve linearity and obtain an effect of adjusting magnetic permeability.

When the content of B as an amorphous forming element is 7 atomic% or more, the amorphous state can be stably formed by rapid cooling, and when it exceeds 20 atomic%, the saturation magnetic flux density Bs decreases. Therefore, the content of B is preferably 7 at% or more and 20 at% or less.

C is an optional component, and may or may not be contained. C has an effect of improving the wettability of the molten metal with the surface of the cooling roll, and is preferably contained in an amount of 0.2 atomic% or more, and preferably 4 atomic% or less depending on the thickness of the produced ribbon, in order to obtain the effect.

The M element (at least one element of Al, Sn, Cr, Mn, Ni, and Cu) may be contained in a range of 2 atomic% or less, although it may not be contained. In particular, an amorphous metal ribbon containing at least one element selected from Al, Sn, and Ni in a range of more than 0 atomic% and 2 atomic% or less can narrow the width of sag, which will be described later, and contribute to an improvement in the life of the mold.

As the amorphous metal ribbon to be subjected to punching, a metal ribbon having a crystallized surface may be used. In this amorphous metal ribbon, the homogeneity of the surface hardness increases, and shear deformation is likely to occur at a lower pressure with the crack as a starting point under a more uniform pressure, so that the occurrence of excessive plastic deformation can be greatly suppressed, and the width of sag, which will be described later, can be reduced.

By adding the element M, an amorphous metal ribbon having surface crystallization can be produced. If the amount of the M element added is 0.03 atomic% or more, the above-mentioned effects are easily obtained. The lower limit of the amount of the M element added is more preferably 0.05 atomic%, and still more preferably 0.1 atomic%.

The amorphous metal ribbon in the present embodiment is preferably manufactured to have a thickness of more than 30 μm and 50 μm or less by a roll quenching method such as a single roll or a twin roll in which raw materials weighed to have a predetermined composition are melted by a method such as high-frequency induction melting and then ejected through a nozzle onto the surface of a cooling roll rotating at a high speed to be quenched and solidified. If the thickness is more than 30 μm, the punching workability of the amorphous metal ribbon can be improved as described above. The thickness is more preferably 30.3 μm or more, still more preferably 30.5 μm or more, still more preferably 31.0 μm or more, still more preferably 32.0 μm or more, and still more preferably 33.0 μm or more.

On the other hand, in the roll quenching method, an amorphous metal ribbon having a thickness of more than 50 μm is easily deteriorated in soft magnetic properties such as coercive force because the cooling rate in the ribbon is lowered and crystallization is easily caused in the ribbon. Further, since the entire ribbon is easily embrittled by crystallization, chipping and cracking are easily generated at the time of punching, and the processing accuracy is deteriorated. Further, although the amorphous metal ribbon is continuously roll-cast and temporarily wound for transportation, the amorphous metal ribbon having a thickness of more than 50 μm is easily broken at the time of winding or unwinding, and is easily applied to mass production. The thickness is preferably less than 40 μm, more preferably 39 μm or less, and further preferably 38 μm or less. When the core is used for a core for high frequency applications such as 20kHz or more, it is particularly preferably less than 40 μm from the viewpoint of soft magnetic characteristics (eddy current loss).

< punching processing >

The step of forming the punched surface of the amorphous metal thin sheet in the punching process of the present embodiment will be described with reference to fig. 2 to 4.

Fig. 2 is a photograph of a punched surface of an amorphous metal sheet. Fig. 3 is a schematic view of fig. 2. As is generally known, a die-cut surface by the die-cutting process has a sagging a (hatched portion), a sheared surface B (hatched portion), a fracture surface C (white portion), and a burr D (gray portion).

Fig. 4 is a schematic diagram for explaining the state of forming the punched surface of the amorphous metal thin sheet in punching. In the figure, 1 denotes an amorphous metal ribbon, 2 denotes a punching die (punch) on the movable side, and 3 denotes a punching die (die) on the fixed side. As shown in fig. 4(a), when the punch 2 is pressed into the surface of the amorphous metal ribbon 1 provided on the die 3, first, the surface of the amorphous metal ribbon 1 is deformed so as to be elastically bent, and a sagging a is formed. As shown in fig. 4(B), when the punch 2 is further pressed, the amorphous metal ribbon 1 is sheared to form a sheared surface B. As shown in fig. 4(C), when the punch 2 is further pressed, the amorphous metal ribbon 1 is broken so as to connect the edges of the punch 2 and the die 3, and a broken surface C is formed. At this time, the amorphous metal ribbon 1 in the vicinity of the edge portions of the punch 2 and the die 3 slightly remains on the side surfaces of the edge portions of the punch 2 and the die 3, and burrs (not shown) are formed. The burr is formed when the sheared surface occupies the entire punched surface, and the atoms move in a large range, and the atoms lost are formed into the burr.

The amorphous metal ribbon 1 has a high vickers hardness and is extremely thin, and therefore has a large variation in elastic deformation. As a result, the contact portions of the amorphous metal ribbon 1 with the edges of the punch 2 and the die 3 are likely to be displaced, and it is difficult to cut (shear) the amorphous metal ribbon at a predetermined position. Therefore, stress concentration on the amorphous metal ribbon 1 by the punch 2 and the die 3 is less likely to occur, and initial fracture such as tearing occurs. In this case, the portion that becomes the starting point of fracture is not necessarily the portion to which the maximum stress is applied, and a portion having relatively weak mechanical strength, that is, a portion having low local hardness may be considered to become the starting point.

For example, the vickers hardness of a 25 μm Fe-based amorphous metal ribbon is measured, and it is confirmed that there is a variation of 750 to 900HV, and even within the same band, the vickers hardness has a standard deviation of about ± 30HV depending on the position. That is, when an imaginary line along the edges of the punch 2 and the die 3 on the Fe-based amorphous metal ribbon is assumed, if the vickers hardness is not largely distributed, the maximum stress is applied to the imaginary line, and the deformation or fracture should be generated on the imaginary line to the same extent. However, in the virtual line of the amorphous metal ribbon, the amorphous metal ribbon is broken from a portion having a low local hardness, and the periphery is deformed so as to be stretched, thereby causing sag.

When the sag is formed, excessive stress is applied to the punch 2 and the die 3, and thus the die wear becomes severe. That is, the die life is shortened, and the manufacturing cost of the motor core is increased. The narrow width of the sag in the punched surface of the amorphous metal sheet means that the life of the die can be increased. Therefore, in the present embodiment, the width of the sag is measured as an index. After the transition from the shear collapse to the shear, the stress applied to the punch 2 and the die 3 is reduced as compared with the shear collapse portion.

As a result of the examination, when the thickness is more than 30 μm, the sagging is greatly reduced (the width of the sagging is 30% or less with respect to the thickness), and the punching workability can be improved. The details are described in the embodiments described later.

The punched amorphous metal sheets are laminated to obtain a laminated core used for a motor or the like. In order to integrate the laminated core without separation, the following known methods can be used: bonding the layers of the amorphous metal sheet with resin; after the amorphous metal sheets are laminated, resin coating, resin impregnation, fastening, and the like are performed.

Examples

(example 1)

By roll cooling, an alloy composition of Fe in atomic%_81.5Si₄B_14.5The amorphous metal ribbon of (1). As shown in table 1, amorphous metal ribbons having a thickness in the range of 22.7 to 35.8 μm were prepared. The thickness of the ribbon was calculated from the density and weight and the dimensions (length x width). Further, the width of the thin strip was 80 mm.

As the punching die, a superhard material (FUJILOY VF-12 material manufactured by Fuji die Co., Ltd.) was used for both the punch and the die. The punch has a rectangular columnar shape with a tip of 5X 15mm and an R portion of 0.3 mm. The die is formed with a processing hole into which the punch is inserted.

An amorphous metal ribbon of each thickness was placed on a die in a state of stacking 1 sheet, and was run under a load of 1400N to perform punching. Then, amorphous metal flakes having a thickness of 5X 15mm were produced. The widths of the sagging edges on the punched surfaces of the amorphous metal thin sheets of each thickness obtained by punching were measured. The width of the sag is the width of the sheet in the thickness direction, and is an average value obtained by measuring arbitrary 5 portions of the punched surface. Any portion of the punched surface can be selected from any punched surface of the amorphous metal sheet. The results are set forth in Table 1.

Fig. 1 is a graph showing the relationship between the thickness of an amorphous metal flake and the width of a sag. The horizontal axis represents the thickness of the amorphous metal flake, and the vertical axis represents the width of the sag.

In the sample No.1 shown in table 1, the end face of the sheet protrudes in the thickness direction so as to be continuously curved beyond the thickness of the sheet, and therefore the width of the sagging is set to the width from the position where the sagging starts to the protruding portion.

As shown in table 1, the sag width of the amorphous metal ribbon having a thickness of 30 μm or less was more than 30% with respect to the thickness of the ribbon. The width of the sag is 10 μm or more. On the other hand, the amorphous metal ribbon having a thickness of more than 30 μm has a sag width of 30% or less with respect to the thickness of the ribbon and a sag width of 5 μm or less. That is, the die life can be improved by making the thickness of the amorphous metal ribbon used in the punching process larger than 30 μm.

[ Table 1]

(the No. attached with star is a comparative example)

On the other hand, an amorphous metal ribbon having a thickness of more than 50 μm is inferior in cooling inside the ribbon, and is crystallized inside the ribbon, so that the soft magnetic characteristics as an amorphous metal ribbon are deteriorated, and thus it is not applicable to the motor core.

Further, since the entire band is embrittled, a chip or a crack occurs even when punching is performed, and a core material having a desired shape cannot be obtained originally. Further, although the amorphous metal ribbon is continuously roll-cast and temporarily wound for transportation, it is assumed that the amorphous metal ribbon having a thickness of more than 50 μm is broken at the time of winding or unwinding, and thus it is difficult to apply the amorphous metal ribbon to mass production.

(example 2)

By roll cooling, an amorphous metal ribbon of alloy composition and thickness shown in table 2 was produced. The amorphous metal ribbon was punched out in the same manner as in example 1 to produce each amorphous metal sheet.

In particular, when an alloy composition containing Al, Sn, and Ni is added, the width of the sag becomes small.

In the Fe-based amorphous alloy, it was confirmed that Al and the like (Al, Sn, Ni, Cu, Cr, Mn) tend to segregate in a large amount in the oxide film on the surface. When surface segregation of Al occurs, so-called surface crystallization in which crystal grains grow in a dendritic manner starting from aggregated Al clusters is likely to occur. When heat treatment is performed in a magnetic field for the purpose of imparting induced magnetic anisotropy, the tape having a crystallized surface cannot effectively impart induced magnetic anisotropy, and the coercive force Hc tends to increase. The increase in coercive force Hc directly leads to an increase in loss in low-frequency applications, for example, in the application of a power distribution transformer. Therefore, in the past, efforts have been made to suppress the concentration of elements such as Al that accelerate surface crystallization to as low a level as possible at the refining stage before casting. However, in applications of medium to high frequencies where high magnetic permeability of anisotropy is not necessarily required, particularly in motor cores and the like, it is not necessary to seek suppression of surface crystallization, and therefore the inclusion of Al or the like may be effective.

The sample surface having undergone surface crystallization is in a state close to the surface of bcc-Fe, and therefore has a lower hardness than the amorphous state, and starts to deform even with a weak load, and therefore, the occurrence of sag can be greatly suppressed. The same effect was confirmed in the substitution of Sn, and it is effective to substitute more than the impurity level (0.03%) with an element that can suppress the surface tension (weaken the surface) and is in a state in which cracks are likely to occur.

Although the mechanism is unknown, the width of the sag is reduced even in the alloy composition to which Ni is added.

In the examples of the present disclosure, the width of the sag can be made 8 μm or less, further 7 μm or less, further 6 μm or less, and further less than 6 μm.

[ Table 2]

(the No. attached with star is a comparative example)

Description of the symbols

1: amorphous metal ribbon, 2: punch, 3: and (4) punching.