JP2002283012A - Iron-base amorphous alloy having good strip forming performance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alloy in which variation of strip thickness in a strip longitudinal direction and a width direction can be made small over a casting even when a difficult gap control, is not carried out, in an iron-base amorphous alloy manufactured with a single roll method or the like. SOLUTION: This alloy is composed by at.% of 78-83% Fe, 2-3% Si, 616 B, 0.2-4% C, 2-12% P and the balance inevitable impurities and has little variation of the strip thickness resulting from the gap variation. It is desirable that the difference between the maximum strip thickness and the minimum strip thickness in the same heat, is <=10% of the strip thickness. Thus, the strip having good strip thickness distribution can be manufactured at good yield and the productivity is improved. The material characteristic is not changed in comparison with the conventional material and the alloy cost does not become high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron-based amorphous alloy produced by a rapid solidification method.

[0002]

2. Description of the Related Art An amorphous alloy can be produced by rapidly solidifying a molten alloy and casting it. As a rapid solidification method, a single roll method, a twin roll method, a centrifugal rapid cooling method, and the like are known. The single-roll method is a method in which a molten alloy is jetted from a nozzle to a circumferential surface of a cooling roll rotating at a high speed, and the twin-roll method is a method in which the molten alloy is supplied between a pair of cooling rolls. The centrifugal quenching method is a method in which a molten alloy is jetted onto the inner peripheral surface of a metal drum rotating at a high speed.

[0003] This amorphous alloy is characterized by its excellent properties.
It is promising as an industrial material in many applications.
Above all, iron-based amorphous alloy ribbons are used for iron core materials such as power transformers and high-frequency transformers because iron loss is low and saturation magnetic flux density and magnetic permeability are high.

[0004] The ribbon cast by the rapid solidification method is peeled from a cooling roll or a drum, and is continuously wound into a coil product. For applications such as laminating ribbons to form an iron core, it is preferable that the thickness variation of the ribbons in the coil (in the charge) be as small as possible. The thickness variation of the ribbon has been considerably improved by improving the control accuracy of manufacturing factors in a rapid solidification process such as a single roll method.

[0005] Among various manufacturing factors, a gap between a nozzle for jetting molten alloy and a cooling roll (this gap is simply referred to as a gap in the present specification).
Is the most difficult factor to control. Other factors such as the peripheral speed of the cooling roll, the nozzle shape, and the ejection pressure of the molten alloy were relatively easy to set, and fluctuations during casting could be suppressed to a small level.

The gap needs to be a very narrow value of 0.5 mm or less. However, it is difficult to measure this narrow gap, and it is difficult to set the gap before casting.In addition, after the start of casting, the heat of the molten alloy causes a thermal crown on the circumferential surface of the cooling roll and the gap fluctuates. There is. As described above, the gap has a large fluctuation factor, and its control is difficult.

The inventors of the present invention have proposed a method for coping with fluctuations in the thickness of a thin strip caused by the generation of a thermal crown of a cooling roll, as disclosed in
0-288694 and JP-A-2000-2886
No. 95 proposes a casting method and a casting nozzle. The basic idea is that if a thermal crown is generated in the cooling roll, the gap becomes narrower at the center in the width direction of the ribbon, and the supply of molten alloy is reduced. The amount is made uniform in the width direction of the ribbon, and the thickness of the ribbon is made uniform in the width direction.

[0008]

SUMMARY OF THE INVENTION The above-mentioned JP-A-2000-2
The techniques disclosed in Japanese Patent No. 88694 and Japanese Patent Application Laid-Open No. 2000-288695 can make the thickness of the ribbon uniform in the width direction in casting after the thermal crown of the cooling roll has grown. However, there remains a problem in making the supply amount of the molten alloy uniform throughout the casting immediately after the start of casting and making the thickness of the ribbon uniform in the length direction.

Therefore, the problem to be solved by the present invention is as follows.
In iron-based amorphous alloy ribbons manufactured by the single-roll method, etc., the thickness variation in the length and width directions of the ribbon can be reduced during casting without difficult gap control. To provide an alloy that can be used.

[0010]

According to the present invention for solving the above-mentioned problems, the present invention provides:
2-3%, B: 6-16%, C: 0.2-4%, P: 2
This is an iron-based amorphous alloy having good ribbon forming ability, characterized by containing about 12%, the balance being unavoidable impurities, and having a small thickness variation due to a gap variation. In the present invention, the difference between the maximum sheet thickness and the minimum sheet thickness of the ribbon of the same charge is
The thickness is preferably 10% or less of the thickness of the ribbon.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The present inventors have found that the degree of variation in the thickness of a thin strip due to variation in the gap depends on the composition of the alloy, and have solved the above-mentioned problems. For the Fe-Si-B-C-P-P alloy, which is known as an inexpensive iron-based amorphous alloy, a strip of various components is cast by the single roll method under the same conditions, and various properties are being investigated. It has been found that there is a thin ribbon having a particularly small variation in the thickness of the charge.

[0012] As described above, the thickness variation in the charge is as follows.
It is mainly caused by the gap fluctuation due to the thermal crown of the cooling roll, suggesting the existence of a specific component composition that reduces the thickness fluctuation due to the gap fluctuation.
Therefore, a casting experiment was performed on the two kinds of components A and B by changing the set gap between the nozzle and the cooling roll by the single roll method, and the thickness variation in the casting direction, that is, the strip length direction in each charge was measured. evaluated. The composition of both components in atomic% is as follows:

Component A: Fe: 80.3%, Si: 2.9
%, B: 9.8%, C: 1%, P: 5.8%, balance: M
Impurities such as n and S. Component B: Fe: 80.3%, Si: 2.5%, B: 1
3.4%, C: 2%, P: 1.6%, balance: impurities such as Mn and S.

For each of the components A and B, a 1 m long sample was taken from the cast ribbon at 300 m intervals for each charge, and the weight and plate width of each sample were measured. The density was 7.26 g / The board thickness was calculated from cm ³ . The result is shown in FIG. ○ and ● are the average values within the charge, and the width is the difference between the maximum and minimum values.

As shown in FIG. 1, there is a clear difference between the component A and the component B, and both the plate thickness variation when the set gap is changed and the plate thickness variation at the same set gap are caused by the component A
Is smaller. The thickness variation at the same set gap indicates a thickness variation due to a gap variation during casting due to a thermal crown of a cooling roll or the like. From the results shown in FIG. 1, it can be seen that the magnitude of the thickness variation due to the gap variation depends on the component composition of the alloy.

Based on these results, various Fe-Si-B-
With respect to the CP alloy, while maintaining good product material properties as a conventional iron-based amorphous alloy, such as the magnetic properties and mechanical properties of the ribbon, the thickness variation due to the gap variation is particularly small. Thus, the present invention was completed by determining the range of the component composition (this is referred to as the plate thickness variation reduction effect). The reasons for limiting the component composition are described below. All contents are atomic%.

If the content of Fe is less than 78%, sufficient mechanical and magnetic properties cannot be obtained. If it exceeds 83%, not only is it difficult to form an amorphous phase, but it is not possible to obtain the effect of reducing the thickness variation. If the content of Si is less than 2% or more than 3%, not only is it difficult to form an amorphous phase, but also the effect of reducing the thickness variation cannot be obtained. B: If it is less than 6%, it becomes difficult to form an amorphous layer, and the effect of reducing plate thickness variation cannot be obtained. If it exceeds 16%, no further effect of reducing the thickness variation can be obtained.

C: Element effective for castability of a ribbon. That is, the addition of 0.2% or more and 4% or less improves the wettability between the molten alloy and a cooling substrate such as a cooling roll,
The cooling rate is increased, and a good ribbon can be formed. 0.2
%, This effect cannot be obtained, and even if it exceeds 4%, no additional effect can be obtained.

P: The most important element in the present invention. If it is less than 2% or more than 14%, the effect of reducing the thickness variation cannot be obtained. Even if Mn, S, etc. are contained as inevitable impurities up to about 0.2%, no particular problem occurs. Since the impurities can be tolerated, the alloy of the present invention is not expensive.

The present inventors have found that, in atomic%, 78% ≦
Fe ≦ 86%, 2% ≦ Si <4%, 5% <B ≦ 16%,
Developed an iron-based amorphous alloy ribbon having a composition of 0.02% ≦ C ≦ 4%, 2% ≦ P ≦ 12% and excellent in soft magnetic properties in alternating current, according to the specification of Japanese Patent Application No. 2000-360195. Although the application has been filed, there is no mention of thickness variation due to gap variation.

The amorphous alloy according to the present invention has an iron loss, a magnetic flux density,
Magnetic properties such as magnetic permeability and mechanical properties such as bendability are not different from those of conventional iron-based amorphous alloys, and the alloy cost is not high. And, with the gap variation based on the setting accuracy before the start of the casting of the ribbon, or the gap variation based on the thermal crown or the like after the start of the casting, the thickness of the ribbon is unlikely to fluctuate as in the related art, and the thickness variation is small. . In the thickness variation of the alloy of the present invention, the difference between the maximum thickness and the minimum thickness of the ribbon of the same charge is reduced to 10% or less of the ribbon thickness.

[0022]

EXAMPLES Alloys of various component compositions were melted, and thin ribbons were cast by a single roll method. Table 1 shows the component composition of each alloy.
Each alloy contains impurities such as Mn and S in a total amount of about 0.2.
Atomic% is contained. Also, the thickness variation of the cast ribbon,
Table 2 shows the evaluation results of the material properties of the ribbon.

The casting conditions of the single roll method are as follows. Cooling roll material: Cu-2 mass% Be copper alloy Cooling roll dimensions: 1200 mm in diameter, 250 mm in width Cooling roll rotation speed: 25 m / s (surface peripheral speed) Gap between ejection nozzle and cooling roll: 200 μm (at the start of casting) Nozzle opening shape: 0.7mm x 120mm slit shape

From the cast ribbon, length 1 at 300m intervals
m, the weight and thickness of each sample are measured, and the thickness is calculated from the density: 7.26 g / cm ³ , and the difference between the maximum value and the minimum value in the charge is calculated as the thickness variation. And Regarding the properties of the ribbon material, the magnetic properties, iron loss, and bendability were evaluated in a sample at a substantially central portion of each charge. The magnetic properties were as follows: maximum magnetic flux density B ₈₀ (T) when an AC magnetic field of 80 A / m was applied, iron loss: 1.3 T, value of 50 Hz (W / kg) It was evaluated by the bending diameter (mm). The annealing condition is 360 ° C ×
1 hr (50 Oersted).

(1) Inventive Examples: In the inventive examples No. 1 to No. 7, casting was possible without any problem at all charges, and a ribbon having good properties was obtained. Then, as shown in Table 2, the thickness variation of the inner ribbon was a small value of 2 μm or less. The magnetic properties and the mechanical properties were all good.

(2) Comparative Example-1: In Comparative Examples No. 8 to No. 11, a thin strip having good properties was obtained by casting.
As shown in the figure, the thickness variation of the inner ribbon was a large value. No. 8 and N for ribbon material
o.11 was good, but No. 9 and No. 10 were insufficiently amorphized, and were inferior in magnetic properties and mechanical properties.

(3) Comparative Example-2: No. 12 and No. 1
In Comparative Example No. 3, a thin ribbon having good properties was obtained by casting, and as shown in Table 2, the thickness variation of the ribbon in the charge was a small value. However, in No. 12, iron loss and bendability were poor due to excessive Fe content and insufficient amorphous formation, and N
o.3 was insufficient in magnetic flux density due to insufficient Fe content.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

The magnetic properties and mechanical properties of the amorphous alloy of the present invention are the same as those of the conventional iron-based amorphous alloy, and the alloy cost is not increased. Then, the gap thickness based on the setting accuracy before the start of casting, or the gap variation based on the thermal crown or the like after the start of casting, can be obtained without performing difficult gap control without changing the thickness in the length and width directions of the ribbon. Fluctuations can be reduced throughout casting, and the difference between the maximum and minimum plate thickness in the charge is reduced to less than 10% of the ribbon plate thickness. Therefore, a thin strip having a good thickness distribution can be manufactured with high yield, and the productivity is also improved.

[Brief description of the drawings]

FIG. 1 is a graph showing an example of the present invention and a comparative example.

Claims (2)

[Claims] (1) Atomic%: Fe: 78 to 83%, Si: 2 to 3%, B: 6 to 16%, C: 0.2 to 4%, P: 2 to 12%, An iron-based amorphous alloy having good strip forming ability, characterized in that the balance is composed of unavoidable impurities and the thickness variation due to the gap variation is small. 2. The iron-based material according to claim 1, wherein the difference between the maximum thickness and the minimum thickness of the ribbon having the same charge is 10% or less of the thickness of the ribbon. Amorphous alloy.