JPH07331396A - Ferrous amorphous alloy excellent in magnetic property and embrittlement resistance and its production - Google Patents

Abstract

PURPOSE:To improve the iron loss properties of an Fe-B-Si amorphous alloy without causing the embrittlement of the material. CONSTITUTION:The molten metal of an alloy having a compsn. shown by the chemical formula: FeXBYSizMna; where 75<=X<= 82at%, 7<=Y<=15at%, 7<=Z<=17at% and 0.2<=a<0.5at% is subjected to rapid solidification in a CO2 atmosphere contg. 1 to 4 % H2. Thus, the amorphous allay having <=0.6mum surface roughness and excellent in magnetic properties can be obtd.

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 having excellent magnetic properties and embrittlement resistance, and a method for producing the same.

[0002]

As disclosed in JP-A-54-148122, JP-A-55-9460 and JP-A-57-137451,
A molten alloy such as Fe-B-Si is injected onto the surface of a cooling roll rotating at a high speed according to a single roll method or the like, and the temperature is 10 ⁵ to 10 ⁶ ° C /
When rapidly solidified at a cooling rate of about s, the plate thickness is several tens of μm
To a degree, so-called amorphous alloy ribbons with disordered atomic arrangement are obtained. Such an amorphous alloy ribbon is easily magnetized, has a low iron loss, and is excellent in so-called magnetic properties,
It has been partially put into practical use as an iron core material for transformers.

However, although such a Fe-B-Si ternary amorphous alloy ribbon can obtain a somewhat low iron loss value, its improvement effect is limited, and in the ternary system, it is lower than that. There was a problem that no loss could be expected.

Therefore, in addition to the above-mentioned ternary amorphous alloy,
Attempts have been made to add various elements as components. For example, in Japanese Examined Patent Publication No. 1-54422, an iron-based amorphous alloy having low iron loss and excellent insulating coating processability is added to Fe—B—Si system with 0.5 to 3 at% of Mn, Ni and the like. Things have been proposed. However, when Mn is added at 0.5 at% or more, a new problem of material embrittlement occurs. In addition, the decrease in magnetic flux density has been a practical problem.

Further, JP-A-62-192560 discloses Fe-B.
-Si system contains 0.05 to 5 at% of one or more selected from Cr, Mo, Ta, Mn, Ni, Co, V, Nb and W, and further the surface roughness by treatment such as rolling. Conditioned amorphous alloys have been proposed. However, JP-A-62-19
In the 2560 publication, no consideration is given to the embrittlement of the material,
Even if the surface roughness is adjusted by a process such as rolling after plate making, it is doubtful whether it will help reduce embrittlement, and it is industrially very inefficient to add such a surface roughness adjustment process separately. Not only that, but also in terms of manufacturing cost.

[0006]

The present invention advantageously solves the above problems and, needless to say, is excellent in magnetic properties, and an iron-based amorphous alloy excellent in embrittlement resistance is The aim is to propose together with its advantageous manufacturing method.

[0007]

[Means for Solving the Problems] As described above, Fe-B
-To improve the iron loss of a Si-based iron-based amorphous alloy, Mn
Although it is effective to add a small amount of Mn, the addition of Mn causes a decrease in magnetic flux density and also has the disadvantage of promoting brittleness of the material. Therefore, the inventors have made extensive studies in order to overcome this disadvantage, and have obtained the following findings. (1) If the Mn content is 0.2 at% or more and less than 0.5 at%,
Iron loss can be improved without significantly reducing the magnetic flux density. (2) The rapid solidification process of the molten metal is performed in a reducing atmosphere, especially in a small amount.
When performed in a CO ₂ atmosphere containing H ₂ , the surface roughness of the ribbon is significantly improved compared to when it is performed in the air, and the oxidation state of the ribbon surface is also modified, resulting in cracking. The cracks that are the starting points of the are less likely to occur, and the embrittlement of the material is effectively suppressed. (3) When the surface roughness is improved, the demagnetizing field due to the magnetic poles caused by the unevenness of the surface is reduced, so that the magnetic flux density is improved. (4) Therefore, if the rapid solidification treatment is performed in the (H ₂ + CO ₂ ) atmosphere to improve the surface properties of the ribbon, the disadvantages such as the decrease in magnetic flux density and the progress of embrittlement due to the addition of Mn are completely eliminated. To be done. The present invention is based on the above findings.

Namely the present invention has the _{formula: Fe X B Y Si Z Mn} a where at 75 ≦ X ≦ 82 at% 7 ≦ Y ≦ 15 at% 7 ≦ Z ≦ 17 at% 0.2 ≦ a <0.5 at% The composition is as shown, and the surface roughness is the centerline average roughness.
It is an iron-based amorphous alloy (first invention) excellent in magnetic properties and embrittlement resistance, characterized in that Ra is 0.6 μm or less.

[0009] The present invention has the _{formula: Fe X B Y Si Z Mn} a where at 75 ≦ X ≦ 82 at% 7 ≦ Y ≦ 15 at% 7 ≦ Z ≦ 17 at% 0.2 ≦ a <0.5 at% When a molten alloy having the composition shown is rapidly solidified to produce an amorphous alloy, the rapid solidification treatment is carried out by adding 1 to 4% H ₂
A method for producing an iron-based amorphous alloy excellent in magnetic properties and embrittlement resistance (second invention), which is characterized in that it is carried out in a CO ₂ atmosphere containing iron.

The present invention will be described in detail below based on the experimental results that have led to the completion of the present invention. Fig. 1 shows the Fe _78-a B ₁₃ Si obtained by rapid solidification treatment in the atmosphere or various atmospheres in which the composition ratio of CO ₂ and H ₂ is changed, followed by heat treatment in a magnetic field of 320 to 400 ° C. shows the results of examining the relationship between (1.3 iron loss value at the time of T frequency:: 50 Hz, magnetic flux density) of ₉ Mn _a iron-based amorphous alloy having a composition, mean and Mn weight iron loss W _13/50 . In addition, FIG. 2 shows the results of an examination of the relationship between the amount of Mn and the magnetic flux density B ₁₀ (magnetic flux density in a magnetic field of 1000 A / m) in an iron-based amorphous alloy having the same composition. In FIG. 2, the magnetic flux density varies with the amount of Mn (hence the band is shown in the figure) because of the influence of the surface roughness. From FIG. 1, it can be seen that low iron loss can be obtained by adding an appropriate amount of Mn to the Fe-B-Si ternary alloy. Further, from FIG. 2, it is understood that although the magnetic flux density tends to decrease with the addition of Mn, the magnetic flux density is improved if the surface quality is good, so that the magnetic flux density practically hardly decreases.

Similarly, in the iron-based amorphous alloy of Fe _81-a B ₁₂ Si ₇ Mn _a composition, the results of investigation on the relationship between the amount of Mn and the average iron loss W _13/50 and the magnetic flux density B ₁₀ are shown. Each,
Shown in FIGS. The variation in magnetic flux density in FIG. 4 is due to the influence of surface roughness. As is clear from FIGS. 3 and 4, low iron loss and high magnetic flux density were obtained also in this case by adding an appropriate amount of Mn. And especially,
When Fe is contained in a large amount exceeding 80% like this alloy composition, there is also an advantage that a higher magnetic flux density can be obtained.

However, such Fe _81-a B ₁₂ Si ₇ Mn
_When the rapid solidification treatment of molten steel of _a composition is performed in the atmosphere, as shown by the broken line in Fig. 5, a reaction occurs from the Mn amount of 0.1 at% to the critical bending height, and as the Mn amount increases, The value will increase. That is, embrittlement proceeds. Here, the critical bending height means the distance between the inner surfaces of the bend just before the ribbon breaks when the alloy ribbon of 150 mm length is bent at the center with the roll contact surface facing outward. It is one of the indicators of the degree of embrittlement. It is said that contact bending is possible when the critical bending height is 0 mm. On the other hand, when the rapid solidification treatment is performed in the CO ₂ atmosphere containing 3% of H ₂ , the critical bending height curve of the obtained amorphous alloy is significantly increased as shown by the solid line in FIG. It can be seen that the brittleness is effectively improved by shifting downward to No.

The difference in the ribbon properties due to the difference in the plate-making atmosphere is well shown in the surface texture, and the surface roughness of the roll surface of the ribbon when the plate is made in the atmosphere is 0.8.
While it is ~ 1.2 μm, it is 0.4-0.6 μm when the plate is made in a CO ₂ atmosphere containing 3% H ₂ , and there are very few irregularities that cause cracks when bent, and it is difficult to crack. It turned out that it has become. In addition, it was also found that by setting the atmosphere to be (H ₂ + CO ₂ ), the oxidation state of the ribbon surface was modified and the embrittlement was further improved. The reason why the surface roughness is improved by performing the rapid solidification treatment in the (H ₂ + CO ₂ ) atmosphere has not been clarified yet, but the main component is CO _2, which has a large specific gravity. In addition to being a gas with high emissivity, it is weakly reducing and suppresses oxidation of the surface of the molten metal so that the surface tension does not decrease and the pool does not collapse easily, so the amount of gas caught between the roll and the molten metal decreases. It is considered that this is due to the interaction between the increase of Mn content in the melt and the decrease of the viscosity of the melt and the viscosity of slag formed on the surface of the melt.

In FIGS. 2 and 4, the amount of Mn added is 0.3.
FIG. 6 shows the result of examining the Ra dependence of the magnetic flux density in the case of at%. As is clear from the figure, the magnetic flux density increases as the surface roughness of the ribbon improves,
The effect is remarkable when Ra is 0.6 μm or less. Therefore,
In the present invention, the surface roughness of the ribbon is the center line average roughness.
Ra was limited to the range of 0.6 μm or less.

[0015]

Next, the reason why the composition of the alloy is limited to the above range in the present invention will be explained. Fe: 75 to 82 at% (hereinafter simply expressed as%) Fe is an important element in determining the properties as a magnetic material. When the Fe content is less than 75%, the magnetic flux density is low, which is not practical. On the other hand, when the Fe content exceeds 82%, the iron loss increases and the thermal stability deteriorates.
It was limited to the range of%. More preferable content range is over 80 ~
82%.

B: 7 to 15% B is a useful element for facilitating the amorphization, but if the content is less than 7%, it becomes difficult to amorphize, while if it exceeds 15%, the magnetic flux density is increased. And the Curie temperature also decrease, so the B content is limited to the range of 7 to 15%.
A more preferable content range is 9 to 13%.

Si: 7 to 17% Si is an element that promotes the amorphization of the material and is useful for the thermal stability of the Curie point, but if the content is less than 7%, the Curie temperature is Is low and not practical, and if it exceeds 17%, the iron loss increases, so the Si content was limited to the range of 7 to 17%. A more preferable content range is 7 to 10%.

Mn: 0.2% or more and less than 0.5% Mn is an element effective in reducing iron loss of the material, but its content is
If it is less than 0.2%, the effect of improving the iron loss is poor, while if it is more than 0.5%, the magnetic flux density decreases with the increase of the Mn addition amount, and at the same time, the embrittlement increases, so the Mn content should be 0.2% or more and less than 0.5%. Limited to the range.

An amorphous alloy can be obtained by subjecting the molten steel adjusted to the above composition range to a rapid solidification treatment. However, if the rapid solidification treatment is performed in the atmosphere during the manufacturing process, the material becomes brittle. Embrittlement of this material causes troubles such as breakage when manufacturing a winding transformer. The smaller the critical bending height of the material is, the more effective it is in preventing such troubles. For example, the shear failure occurrence rate of those that can be closely bent is zero, the shear failure occurrence rate is 0.2% even when the critical bending height is 0.10 mm, and the trouble occurrence rate is 0.8% when the critical bending height is 0.25 mm. %Met. So, in this invention,
By carrying out the rapid solidification treatment in a CO ₂ atmosphere containing H ₂ in the range of 1 to 4%, the surface roughness Ra is 0.6 μm or less, and the oxidation of the ribbon surface is reduced, so that the material It effectively prevents embrittlement and also improves the magnetic flux density.

The main component of the atmosphere during the rapid solidification is CO ₂ gas, which is an inert gas that can be obtained at a low cost and is a three-element gas, so that it has a high emissivity and a high specific gravity. Since it is also large, it is effective in reducing the surface roughness due to gas entrainment. Also this C
The amount of H ₂ gas that should be mixed in O ₂ gas is limited to the range of 1 to 4% because the surface roughness of the surface roughness is not sufficient if the amount of H ₂ gas is less than 1%. Not only can Ra be less than 0.6 μm, but also the reduction of surface oxidation will be insufficient. On the other hand, if it exceeds 4%, the danger of explosion and other handling difficulties will increase, and if the amount of hydrogen increases. This is because hydrogen penetrates from the surface and becomes brittle. Thus, an amorphous alloy ribbon having a high magnetic flux density and a low iron loss can be obtained without fear of embrittlement.

[0021]

【Example】

Example 1 Molten alloy melts having various component compositions as shown in Table 1 were injected on the surface of a Cu roll rotating at a high speed in an atmosphere tank in which CO ₂ gas containing 3% H ₂ was substituted after evacuation. And thickness:
After forming an amorphous alloy ribbon with a width of 25 μm and a width of 10 mm, 320 to 42
Annealing was performed in a magnetic field at 0 ° C. for 1 hour. Table 1 also shows the results of measurement of the iron loss value, magnetic flux density, and surface roughness of the roll contact surface of the iron-based amorphous alloy ribbon thus obtained.

[0022]

[Table 1]

As is clear from Table 1, all the amorphous alloy ribbons obtained according to the present invention have a low iron loss value and a high magnetic flux density. In addition, in both cases, the critical bending test allowed close bending and was also good in terms of embrittlement resistance.

Example 2 Fe _80.6 B was _{prepared in the same} manner as in Example 1 except for the rapidly solidified atmosphere.
An iron-based amorphous alloy of ₁₂ Si ₇ Mn _0.4 composition (thickness: 25 μm) was produced. Table 2 shows the results of an investigation of the surface roughness and the critical bending height of the roll contact surface of each of the obtained ribbons, on the atmosphere dependence and magnetic properties during rapid solidification.

[0025]

[Table 2]

As is clear from Table 2, the surface roughness and the critical bending height of the ribbon change depending on the difference in the atmosphere during rapid solidification, and when produced in an atmosphere satisfying the present invention, The centerline average roughness Ra is as small as 0.5 μm,
Further, it was possible to perform tight bending, and the embrittlement resistance was good. Also,
All of the thin strips obtained according to the present invention had excellent magnetic characteristics such as high magnetic flux density and low iron loss. On the other hand, when the atmosphere is inappropriate, the centerline average roughness Ra is 0.6
The critical bending height also increased as the thickness exceeded μm and Ra increased, and embrittlement proceeded.

[0027]

Thus, according to the present invention, Fe-B-Si
The iron loss of the amorphous alloy can be improved without lowering the magnetic flux density. Further, in the present invention, by carrying out the rapid solidification treatment in a CO ₂ atmosphere containing a small amount of H ₂ , it is possible to effectively reduce the embrittlement of the material due to the addition of Mn, and prevent troubles during transformer assembly. it can.

[Brief description of drawings]

FIG. 1 shows an iron-based amorphous alloy having _a composition of Fe _78-a B ₁₃ Si ₉ Mn _a ,
It is a graph showing the relationship between the amount of Mn and the average iron loss W _13/50 .

FIG. 2 shows an iron-based amorphous alloy having _a composition of Fe _78-a B ₁₃ Si ₉ Mn _a ,
6 is a graph showing the relationship between the amount of Mn and the magnetic flux density B ₁₀ .

FIG. 3 shows an iron-based amorphous alloy having _a composition of Fe _81-a B ₁₂ Si ₇ Mna,
It is a graph showing the relationship between the amount of Mn and the average iron loss W _13/50 .

FIG. 4 shows an iron-based amorphous alloy having _a composition of Fe _81-a B ₁₂ Si ₇ Mna,
6 is a graph showing the relationship between the amount of Mn and the magnetic flux density B ₁₀ .

FIG. 5 shows an iron-based amorphous alloy having _a composition of Fe _81-a B ₁₂ Si ₇ Mn _a ,
It is the graph which showed the critical bending height by the difference of atmosphere at the time of rapid solidification in relation to the amount of Mn.

FIG. 6 Fe _77.7 B ₁₃ Si ₉ Mn _0.3 composition and Fe _80.7 B ₁₂ Si ₇ M
6 is a graph showing the relationship between the average roughness of the central part and the magnetic flux density of an iron-based amorphous alloy having an n _0.3 composition.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiji Okabe, 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Steel Research Laboratory, Kawasaki Steel Co., Ltd. (72) Nobuyuki Shiga, 1 Kawasaki-cho, Chuo-ku, Chiba-shi (72) Inventor Mitsuharu Ozawa 2-3-3 Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Kawasaki Steel Mfg. Co., Ltd.

Claims (2)

[Claims] 1. A chemical formula: Fe _{X BY} Si _Z Mn _a where 75 ≦ X ≦ 82 at% 7 ≦ Y ≦ 15 at% 7 ≦ Z ≦ 17 at% 0.2 ≦ a <0.5 at% And the surface roughness is the centerline average roughness.
An iron-based amorphous alloy excellent in magnetic properties and embrittlement resistance characterized by Ra of 0.6 μm or less. 2. A chemical formula: Fe _{X BY} Si _Z Mn _a where 75 ≦ X ≦ 82 at% 7 ≦ Y ≦ 15 at% 7 ≦ Z ≦ 17 at% 0.2 ≦ a <0.5 at% When an amorphous alloy is produced by rapid solidification of the molten alloy to form an amorphous alloy, the rapid solidification treatment is performed by adding 1 to 4% H ₂
A method for producing an iron-based amorphous alloy having excellent magnetic properties and embrittlement resistance, which is characterized in that it is carried out in a CO ₂ atmosphere containing iron.