JPH10280034A - Method for heat treating fe base amorphous alloy thin strip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treating method for an Fe base amorphous alloy thin strip in which the improvement of the dispersion of core loss between each charge is made possible, furthermore, the core loss itself can be improved, and as a result, the improvement of the yield of the thin strip is made possible even in the case an inexpensive alloy is used. SOLUTION: An amorphous thin strip produced by melting an alloy whose compsn. is shown by (Fea Sib Bc Cd )100-x Px and jetting the allay molten metal onto a moving cooled substrate through a slot nozzle is subjected to low temp. annealing in the temp. range of 150 to 320 deg.C for 30 sec to 1 hr and is thereafter subjected to magnetic annealing at 340 to 400 deg.C for 30 min to 3 hr, where, as for (a), (b), (c) and (d), by atomic %, 70<=a<=86, 1<=b<=19 7<=c<=20, 0.02<=d<=4 and a+b+c+d=100, and as for (x), by wt.%, 0.03<=x<=0.1. The thin strip having <=30 μm sheet thickness is preferably produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Fe-based amorphous alloy ribbon used for an iron core of a power transformer, a high-frequency transformer and the like, and a method for producing the same.

[0002]

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

[0003] This amorphous alloy ribbon is regarded as a promising industrial material in many applications because of its excellent properties. Among them, iron core materials such as power transformers and high-frequency transformers are used for low iron loss and high saturation magnetic flux density and high magnetic permeability. -Si-B type or the like is employed.

The present inventors disclosed in Japanese Patent Application Laid-Open No. 8-283919 that 0.003% by weight of P was added to the Fe-Si-BC system.
The thickness of the alloy ribbon having a composition of not less than 0.1% by weight is not less than 40 μm and the thickness of the ribbon is not more than 90 μm to improve the iron loss, and the average cooling rate from the melting point of the composition to 400 ° C. 1 × 10 ⁵ ℃ / sec or more 2 × 10 ⁵ ℃
A method has been disclosed for improving iron loss by cooling at a rate of less than / sec. The present inventors have also disclosed in Japanese Patent Application No. 7-3323.
In No. 40, 0.0 as an impurity was added to the Fe-Si-BC system.
P of not less than 08% by weight and not more than 0.1% by weight, 0.15% by weight
An inexpensive amorphous alloy ribbon containing Mn of not less than 0.5% by weight and S of not less than 0.004% by weight and not more than 0.05% by weight has been filed. Japanese Patent Application No. 7-332340 has been achieved by adding P to render Mn and S impurities harmless.

[0005] The present inventors have used an inexpensive alloy containing P, Mn and S as impurities disclosed in Japanese Patent Application Laid-Open Nos. 8-283919 and 7-332340,
An amorphous alloy ribbon having a thickness of about 20 μm to 70 μm is cast by a normal single-roll method, and a known strain relief annealing is performed.
The iron loss of the sample subjected to annealing in a magnetic field of 1 ° C. × 1 hour was evaluated. As a result, when the plate thickness is more than 30 μm, the iron loss (W13 / 50) measured under the conditions of 50 kHz and 1.3 T using the single plate test (SST) is 0.09 to 0.12 W / kg.
And an excellent low iron loss value. However, when the sheet thickness is 30 μm or less, even if the iron loss is cast into a ribbon having the same composition of 0.09 to 0.16 W / kg and the same thickness, the variation of the iron loss between each charge increases, and the same. It was also found that the average value of the iron loss in the plate thickness was increased.

The following are disclosed as P-containing Fe-Si-B alloys. JP 5
JP-A-7-137451 discloses that Fe is more than 78.5 at% and less than 80 at%, Si is 5 to 10 at%,
It is disclosed that by regulating B to 13 at% or more and 16 at% or less, the flowability of molten metal at the time of casting is improved, and the thermal stability of the ribbon is improved. However, the maximum allowable amounts of various impurity elements are shown, for example, P is 0.008
Atomic% or less, Mn is 0.12 atomic% or less, S is 0.02 atomic% or less.
Atomic% or less is specified.

Further, Japanese Patent Application Laid-Open No. 57-185957 discloses that, in order to improve the saturation magnetic flux density of a ribbon and to reduce the loss, in an Fe—Si—B—C—P system, P is 1 atomic%. An alloy composition characterized by adding at least 10 atomic% or less is disclosed. JP-A-8-193252 discloses that 6 to 10 atomic% of B, 10 to 17 atomic% of Si,
A low boron amorphous alloy consisting of 0.02 to 5 atomic% P and the balance Fe is disclosed. This is B for cost reduction
Even if the amount is lower than in the conventional case, the surface roughness of the ribbon is improved by adding P, and the same soft magnetic properties as in the case of high B content are obtained.

However, Japanese Patent Application Laid-Open No. 57-13745 discloses such a method.
No. 1, JP-A-57-185957 and JP-A-8-193252 disclose a method of manufacturing a ribbon by casting a ribbon by a usual single-roll method and then subjecting the ribbon to a normal single-stage distortion. This is a method of performing annealing in a magnetic field.

[0009]

As described above, conventionally, even when a thin strip is cast using an inexpensive alloy containing P, Mn, S, etc. as impurities, if the sheet thickness becomes 30 μm or less, It has been found that even if the same composition and the same thickness are cast, the variation in iron loss between charges increases, and the average value of iron loss also deteriorates.

According to the present invention, even when the above-mentioned inexpensive alloy is used, the low-temperature annealing is performed after the strip casting and before the strain relief annealing which is usually performed, so that even when the strip has a thickness of 30 μm or less, Iron loss variation between charges can be improved, and iron loss itself is also improved,
As a result, an object of the present invention is to provide a heat treatment method for an Fe-based amorphous alloy ribbon, which can improve the yield of the ribbon.

[0011]

The gist of the present invention is as follows. (1) composition _{(Fe a Si b B c C} d) 100-x P x
Is melted, and the molten alloy is ejected through a slot nozzle onto a moving cooling substrate to form an amorphous ribbon produced at a temperature in the range of 150 ° C to 320 ° C.
After performing low temperature annealing for 0 second or more and within 1 hour, 340
A heat treatment method for an Fe-based amorphous alloy ribbon, comprising annealing in a field at a temperature of not less than 400C and not more than 400C for not less than 30 minutes and not more than 3 hours. However, a, b, c and d are atomic%, 70 ≦ a ≦ 86, 1 ≦ b ≦ 19, 7 ≦ c ≦ 20,
0.02 ≦ d ≦ 4, a + b + c + d = 100, and x
Is 0.003 ≦ x ≦ 0.1 in weight%. (2) The heat treatment method for an Fe-based amorphous alloy ribbon according to the above (1), wherein a ribbon having a plate thickness of 30 μm or less is manufactured.

In order to improve iron loss even in a thin strip having a thickness of 30 μm or less cast using an inexpensive alloy, the present inventors have attempted to improve the rotation speed of the roll, the distance between the roll and the nozzle, and the pressure of the molten metal jet. I tried various things, such as changing, but it was not successful. Therefore, in a system containing P,
Since the cooling rate and the iron loss are closely related, the profile of the cooling rate of the ribbon during casting was examined in detail using a well-known contact thermocouple with the profile and the iron loss. As a result, in the conventional casting method, in most cases, when the thickness of the ribbon becomes 30 μm or less, the ribbon becomes 100
It was found that cooling was performed at a sufficiently high cooling rate to a temperature of about ° C. At the same time, in the conventional casting method, the ultimate temperature of the ultra-rapidly cooled ribbon on the cooling substrate changes within the range of several tens of degrees Celsius, and the temperature is accidentally increased to 150 degrees Celsius or more.
Only when the temperature falls within the range of 0 ° C or less, W13 / 50
It has been found that excellent iron loss of 2 W / kg or less can be obtained. However, in most cases, the ultimate ribbon temperature is
Since the temperature did not fall within the temperature range of 50 ° C. or more and 320 ° C. or less, good iron loss was not obtained, and this caused variation in iron loss.

It is generally considered that the structure formed by continuous cooling from a high temperature is different from the structure formed by annealing once cooled. Particularly, in a metastable material such as an amorphous material, the difference between the two becomes more remarkable. However, based on the above experimental results, the present inventors conducted a heat treatment to determine whether iron loss can be improved by performing low-temperature annealing before performing strain relief annealing even on a ribbon cast by a conventional method. The temperature and time were varied and examined in detail. As a result, the ultra-rapidly cooled ribbon was
After performing low-temperature annealing in a temperature range of 20 ° C. or less for 30 seconds or more and 1 hour or less, and then performing strain relief annealing in a magnetic field at a temperature of 340 ° C. or more and 400 ° C. or less for 30 minutes or more and 3 hours or less, It has been newly found that the loss is improved and the variation between charges is reduced. 150
Annealing at a temperature lower than ℃ or a temperature higher than 320 ° C. does not provide the effect of improving iron loss.

Regarding the mechanism of iron loss improvement,
Although not clear, only by low-temperature annealing in the temperature range of 150 ° C. or more and 320 ° C. or less, P is clustered in some form or precipitates as fine precipitates in the amorphous matrix, and they reduce iron loss. It is presumed to have contributed. If the time of the low-temperature annealing is shorter than 30 seconds, the variation of the iron loss is not improved. Further, even if the annealing is performed for one hour or more, the improvement of the iron loss improvement effect is not recognized, and the cost such as electricity cost is increased. Therefore, the condition of the low-temperature annealing is limited to a temperature of 150 ° C. or more and 320 ° C. or less and 30 seconds or more and 1 hour or less.

In the subsequent strain relief annealing in a magnetic field, when the temperature is lower than 340 ° C. and when the time is shorter than 30 minutes, the iron loss is deteriorated because the strain cannot be completely removed. In addition, when annealing is performed at a temperature exceeding 400 ° C., crystallization occurs partially. Even if the annealing time is longer than 3 hours, no improvement in iron loss is recognized, and depending on the composition, partial crystallization may occur and the iron loss may deteriorate. Therefore, the conditions for annealing in a magnetic field are set to 34.
The temperature was limited to 30 ° C. or more and 3 hours or less at a temperature of 0 ° C. or more and 400 ° C. or less. After the low temperature annealing, the strain relief annealing may be performed after cooling to room temperature, or the strain relief annealing may be performed without cooling after the low temperature annealing. Even when the low-temperature annealing according to the present invention is applied to a ribbon having a thickness of more than 30 μm, the variation in the iron loss is further improved, and in most cases, the W13 / 50 is 0.10 W / kg or less.

Next, the reasons for limiting the alloy composition will be described.
When a ribbon is used for the iron core, the saturation magnetic flux density of the iron core is 1.
It is necessary to set a high value of 5T or more. For that, Fe
Must be 70 atomic% or more. On the other hand, if the Fe content exceeds 86 atomic%, it becomes difficult to form an amorphous phase, and good ribbon properties cannot be obtained. Therefore, Fe is limited to the range of 70 at% to 86 at%.

Si and B are added to improve the ability to form an amorphous phase and the thermal stability. If Si is less than 1 at% and B is less than 7 at%, amorphous is not formed stably. On the other hand, if Si is more than 19 at% and B is more than 20 at%, the cost of raw materials is only high, No improvement in amorphous forming ability and thermal stability is observed. Therefore, it is preferable that Si is 1 to 19 atomic% and B is 7 to 20 atomic%.

C is an element effective for improving the castability of the ribbon. By containing C, the wettability between the molten metal and the cooling substrate is improved, and a good ribbon can be formed.
If C is less than 0.02 atomic%, this effect cannot be obtained. Further, even if C is contained in an amount of more than 4 atomic%, no improvement in this effect is recognized. Therefore, C is set to 0.0
It is limited to 2 atomic% or more and 4 atomic% or less.

In order to further stabilize the magnetic characteristics,
Fe at least 77 atomic% and at most 83 atomic%, Si at 2 atomic%
It is preferable that the content of B is not less than 9 atomic% and the content of B is not less than 11 atomic% and not more than 17 atomic%.

If P is less than 0.003% by weight, a sufficient iron loss improving effect cannot be obtained. Further, even if the content exceeds 0.1% by weight, no improvement in the iron loss improving effect is observed. Therefore,
The P content was limited to 0.003% by weight or more and 0.1% by weight or less.

As impurities, Mn is 0.15% by weight or more and 0.5% by weight or less, and S is 0.004% by weight or more and 0.05% by weight.
It is also possible to use an inexpensive iron source containing Mn and S, such as below% by weight. In this case, P is 0.008% by weight.
By positively containing Mn and S in the range of 0.1% by weight or less, these Mn and S can be rendered harmless. When Mn exceeds 0.5% by weight and S exceeds 0.05% by weight, even if P is contained in an amount of 0.008% by weight or more and 0.1% by weight or less, they cannot be rendered harmless. Therefore, it is desirable that Mn is 0.5% by weight or less and S is 0.05% by weight or less. On the other hand, when Mn is less than 0.15% by weight or when S is less than 0.004% by weight, it is no longer possible to use an inexpensive iron source, which is expensive and of high purity as in the past. Iron sources must be used. As a result, the alloy cost is undesirably increased. Therefore, it is desirable that Mn is 0.15% by weight or more and S is 0.004% by weight or more.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The ribbon of the present invention melts a predetermined alloy component, jets the molten metal through a slot nozzle or the like onto a cooling substrate moving at a high speed, and rapidly solidifies the molten metal. For example, it can be manufactured by a single roll method or a twin roll method. Single-roll devices include a centrifugal quenching device that uses the inner wall of the drum, a device that uses an endless type belt, and an improved version of these auxiliary rolls or a roll surface temperature control device that is attached under reduced pressure or vacuum. Or a casting apparatus in an inert gas. In the present invention, the dimensions such as the width of the ribbon are not particularly limited,
For example, the plate width is preferably 20 mm or more.

Using the ribbon obtained by such a method,
For example, when manufacturing a wound iron core transformer, a thin ribbon is wound in a toroidal shape, and a 150 mm according to the present invention is used.
Low-temperature annealing at a temperature of at least 320C and a temperature of 320C or less may be performed, and then annealing for removing strain in a magnetic field may be performed. Since the low-temperature annealing of the present invention is different from the strain relief annealing, it can be performed even if it is not in a final toroidal shape. For example, after casting, before winding, the ribbon should be at least 150 ° C and 320 ° C.
It is also possible to pass through a low-temperature heating furnace maintained below, or to perform low-temperature annealing all at once on the wound coil stage.

[0024]

The present invention will be further described below with reference to examples. Example 1 An alloy containing 0.018 wt% of P in Fe80.5Si2.5B16C1 (atomic%) was cast into a ribbon by a single roll method. The single roll ribbon manufacturing apparatus used has a diameter of 58
It consists of a 0 mm copper alloy cooling roll, a high-frequency power supply for melting the sample, a quartz crucible with a slot nozzle at the tip, and the like. The stripping temperature of the ribbon measured by a known contact thermocouple was 90 ° C.

A part of the ribbon for one charge is cut to a length of 120 mm, low-temperature annealing is performed at a temperature of 100 ° C. to 330 ° C. for a different time, and then a strain in a magnetic field at 360 ° C. for 1 hour is performed. An annealing test was performed to produce a test piece for evaluation. SST (Single Strip)
Tester) was used. The measurement conditions were as follows.
3T, frequency 50 Hz.

In this experiment, the length was 25 mm and the width was 0.4
mm single slot nozzle, plate thickness is about 25
A μm ribbon was obtained.

The results are shown in Table 1.

[0028]

[Table 1]

From the results shown in Table 1, it is found that
By performing a low-temperature anneal at 30 ° C. or less for 30 seconds to 1 hour before the strain relief annealing, 0.12 W /
A ribbon having an iron loss value of not more than kg is obtained. In addition, heat treatment No. 17 and 18 show that even if the low-temperature annealing time exceeds 1 hour, no further effect of improving iron loss is observed.

Example 2 In the same manner as in Example 1, a thin strip having a thickness of about 25 μm was cast by one charge, and a low-temperature anneal was performed at 230 ° C. for 5 minutes, and then the time was changed in a temperature range of 330 to 420 ° C. Heat treatment was performed to produce a test piece for evaluating iron loss. The stripping temperature of the ribbon was 95 ° C. Table 2 shows the results measured using SST.
Shown in

[0031]

[Table 2]

From the results shown in Table 2, the low-temperature annealing according to the present invention is followed by a strain relief annealing at 340 ° C. to 400 ° C. for 30 minutes to 3 hours to obtain an iron loss of 0.12 W / kg or less. A ribbon having a value was obtained.

Embodiment 3 As in the case of the embodiment 1, the ribbon is charged 8 times (Nos. 3 to 10).
It was cast and evaluated for iron loss. The thickness of the ribbon is 20 ~ 60μm
Was changed within the range. The actual measurement result of the stripping temperature of the ribbon is shown in Cast Charge No. 3 to 6 are in the range of 90 to 110 ° C. 7 to 10 was in the range of 150 to 280 ° C. For casting of thick ribbon, length 25mm,
A double slot nozzle having a width of 0.4 mm was used. The slot interval is 1 mm. After performing low-temperature annealing for 5 minutes on the ribbons of each thickness, strain removing annealing was performed at 360 ° C. for 1 hour in a magnetic field. As a comparison, a test piece subjected to only strain relief annealing without performing low-temperature annealing was also manufactured. Table 3 shows the iron loss evaluation results.

[0034]

[Table 3]

Casting charge No. From the comparison of the presence or absence of the low-temperature annealing of 3 to 6, the iron loss is improved by performing the low-temperature annealing according to the present invention for the ribbon having a thickness of 30 μm or less, and the thin sheet having the iron loss of 0.12 W / kg is obtained. You can get a belt. On the other hand, casting charge No. From the comparison of the presence or absence of low-temperature annealing of 7 to 10, it can be seen that the iron loss of 0.12 W / kg or less can be obtained without using the present invention in a ribbon having a thickness of more than 30 μm.

Embodiment 4 In the same manner as in Embodiment 1, 6 thin strips were charged (Nos. 11 to 1).
6) Cast. The target plate thickness was set to 25 μm and 30 μm, and three charges were cast under each casting condition to evaluate the variation between rods, and the iron loss was evaluated. The stripping temperature of the ribbon was in the range of 85 to 105 ° C. The iron loss at each charge was determined by collecting three SST test pieces from the top, middle, and bottom of the ribbon, measuring a total of 9 iron losses at each charge, and calculating the average value of each. The iron loss value of the charge was used. For each charge, a comparison was made between the case where low-temperature annealing was performed at 250 ° C. for 5 minutes and the case where no low-temperature annealing was performed. The strain relief annealing was performed at 360 ° C. for 1 hour in a magnetic field. Table 4 shows the results.

[0037]

[Table 4]

From the results shown in Table 4, it can be seen that by performing the low-temperature annealing according to the present invention, the iron loss is improved and the variation is significantly reduced.

Example 5 A thin strip having a thickness of 25 μm was cast in the same manner as in Example 1 by using an alloy having a composition of Fe78Si9.5B12C0.5.
After low-temperature annealing at 50 ° C. for 5 minutes, a strain relief annealing at 360 ° C. for 1 hour was performed in a magnetic field. No iron loss improvement effect was obtained. This is because P is not contained in the ribbon.

[0040]

According to the present invention, even when a ribbon having a thickness of 30 μm or less is cast using an inexpensive alloy, a ribbon having excellent iron loss can be obtained by a simple heat treatment thereafter. Variations between charges can be significantly reduced, and the yield can be improved.

Claims (2)

[Claims] 1. A composition _{(Fe a Si b B c C} d)
_100-x was dissolved P _x alloy to be displayed, in amorphous ribbon produced by ejecting through a slot nozzle to the cooling substrate which is moving the alloy melt, 0.99 ° C. or higher 320 ° C.
A low-temperature anneal in the following temperature range for 30 seconds to 1 hour, followed by annealing in a magnetic field for 30 minutes to 3 hours at a temperature of 340 to 400 ° C. Heat treatment method for alloy ribbon. Where a,
b, c and d are atomic%, 70 ≦ a ≦ 86, 1 ≦ b
≦ 19, 7 ≦ c ≦ 20, 0.02 ≦ d ≦ 4, a + b + c
+ D = 100, and x is 0.003 ≦ x ≦% by weight
0.1. 2. The heat treatment method for an Fe-based amorphous alloy ribbon according to claim 1, wherein a ribbon having a thickness of 30 μm or less is manufactured.