JPH0459950A - Fe-co alloy excellent in magnetic property and cold workability - Google Patents

Abstract

PURPOSE:To produce an alloy excellent in magnetic properties and cold workability and suitable for magnetic circuit material by preparing an Fe-Co alloy having a specific composition in which respective contents of Co and Zr are specified. CONSTITUTION:An Fe-Co alloy excellent in magnetic properties and cold workability can be obtained by preparing an alloy having a composition consisting of, by weight ratio, 33-37% Co, 0.005-0.30% Zr, <=0.02% (C+N), and the balance Fe with impurity elements. If Si is further incorporated by 0.03-0.30%, the surface of an ingot can be improved and cost reduction due to improvement in yield can be attained. Moreover, cold workability can be improved to a greater extent by incorporating one or >=2 kinds among 0.005-0.30% Ti, 0.005-0.30% Nb, 0.005-0.30% Ta, and 0.01-0.40% B.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an Fe--Co alloy that has excellent magnetic properties and cold workability and is suitable as a material for magnetic circuits in electrical equipment and the like.

(Prior art) In recent years, there has been an extremely strong demand for higher performance, smaller size, and lighter weight for magnetic circuits in electrical equipment, etc., and in order to make these demands possible, there is a strong need to develop materials with high saturation magnetic flux density. requested.

Conventionally known alloys with high saturation magnetic flux density include Fe containing approximately 35 to 50% Co by weight.
-Co alloys, especially Fe-35%Co
The alloy Fe-50%Co alloy is well known. These alloys have a high saturation magnetic flux density of 24000G or more and have excellent coercive force, but 50% Co
Because it forms a regular lattice with a composition centered on

Subsequently, research was carried out to improve the cold workability of the Fe-Co alloy mentioned above, and it became clear that ■ could suppress the formation of an ordered lattice in the Fe-Co alloy and improve the cold workability. Therefore, Fe-49%C0-2%V alloy was developed and is still in use today. However, as a result of adding 2% of ■, this alloy has a saturation magnetic flux density of 23,000
At the same time, the transformation temperature from α to T phase decreased significantly. Therefore, in order to avoid deterioration of the saturation magnetic flux density due to transformation strain during magnetic annealing, the annealing temperature must be kept low. As the processing strain disappeared incompletely, even the coercive force deteriorated. Furthermore, due to the high Co content and poor vortex flow during solidification after melting, the surface of the steel ingot becomes uneven, and the amount of skin scraping on the surface of the steel ingot increases, resulting in high prices and problems that hinder the expansion of applications. It became.

(Problems to be Solved by the Invention) The present invention relates to Fe-35%Co alloy and Fe-50%Co alloy.
By significantly improving cold workability compared to alloys, it is possible to manufacture thin sheets by hoop rolling, and it has the highest saturation magnetic flux density among hoop rolling materials, and Fe-4
This was proposed for the purpose of providing an Fe--Co alloy that has a coercive force equal to or higher than that of the 9%C0-2%■ alloy, and is inexpensive.

(Means for Solving the Problems) The present inventor has discovered that the brittleness of Fe-Co alloys
O's 1 to 1! Focusing on the fact that the formation of an ffl-structured regular lattice and the associated increase in hardness are the causes, C.

The content is 51.35χ (by weight ratio, which is the composition of the regular lattice)
It was considered that it was necessary to lower the degree of regularity by lowering the atomic number ratio from 50χ). In addition, in order to minimize the decline in magnetic properties and improve cold workability, it is necessary to add another component element that can reduce regularity and improve cold workability with a smaller amount than ■. I thought I needed to find out. Therefore, we reduced the degree of order by lowering the Co content to about 35%, which ensures the highest saturation magnetic flux density, and further added various alloying elements to reduce the degree of order and improve cold workability per unit addition amount. The degree of improvement was investigated. As a result, the five elements Zr, Ti, Nb, Ta, and B were
The effect is very large compared to that of 0.005 to 0.30 to 0.40%, which results in a greater reduction in regularity than when adding 2% of ■, and a correspondingly large improvement in cold workability. It was found that it was possible to obtain In particular, Zr has a large effect, so 0.00% Zr is added to the Fe-35%Co alloy.
Add 5-0.30% Zr, Ti, N if necessary
By adding b, Ta, and B, Fe-35%Co
This material succeeded in improving cold workability without reducing saturation magnetic flux density compared to alloys. In addition, regarding the improvement of coercive force, which is another aim of the present invention, C
Compared to the conventional Fe-49% Go-2% ■ alloy, the coercive force is slightly inferior to that of the Fe alloy containing approximately 50% of ] As a result of suppressing the temperature to about 00°C and making it possible to perform heat treatment at a high magnetic annealing temperature, the conventional Fe-49%C0-2%
This makes it possible to obtain a coercive force equal to or higher than that of V alloy.

Furthermore, as a result of conducting research on a component system that can improve the surface texture of steel ingots, the present inventors confirmed that adding a small amount of Si to the above-mentioned invention has a large improvement effect, and that a small amount hardly deteriorates the magnetic properties. This is what I did.

That is, the first invention of the present invention has a weight ratio of Co:3.
3-37%, Zr: 0.005-0.30%, C+
This is a patent characterized in that N: 0.02% or less is contained, with the remainder consisting of Fe and impurity elements, and the second invention is characterized in that the first invention contains 0.03 to 0.3% of Si.
By containing 0% of steel, the surface texture of the steel ingot is improved, and cost reduction is possible due to improved yield.

Moreover, the third invention has Ti:0 in the component of the first invention.

005-0.30%, Nb: 0.005-0.30%,
Ta: 0.005-0.30%, B: 0.

The fourth invention further improves cold workability by containing one or more of Si in an amount of 0.01 to 0.40%.

Containing 30% of steel improves the surface roughness of the steel ingot and makes it possible to reduce costs by improving yield.

Next, the Fe-
The reason for limiting the composition of the Co-based alloy will be explained.

Co: 33-37% Co is an essential basic element for the present invention in order to ensure excellent saturation magnetic flux density and coercive force, and in order to obtain this effect, it must be contained in an amount of 33% or more. However, if the content exceeds 37%, the degree of regularity increases, resulting in poor cold workability and increased cost.

Zr; 0.005% to 0.30% Zr is the most important element in the present invention, and has the effect of greatly improving cold workability. Containment is necessary. However, if it is contained excessively, the saturation magnetic flux density will decrease, the transformation temperature will also decrease, and the coercive force will deteriorate, so the upper limit should be set at 0.3
It was set to 0%.

C+N: 0.02% or less C and N are mixed as impurities during melting and steel manufacturing, but since they lower the saturation magnetic flux density, it is desirable to reduce them as much as possible, and the upper limit is set at 0.02%.

Si: 0.03 to 0.30% Si4 is an element that is effective in improving the surface texture of steel ingots and increasing yield, and in order to obtain this effect, the content should be 0.

It is necessary to contain 0.3% or more. However, since a large amount of content lowers the saturation magnetic flux density, the upper limit should be set at 0.30.
%.

Ti, Nb, Ta; 0.005-0.30% Ti,
Like Zr, Nb and Ta are elements that improve cold workability.
% or more. However, when the content exceeds 0.30%, the saturation magnetic flux density decreases, the transformation temperature decreases, and the coercive force also deteriorates.

B; 0.01 to 0.40% B is an element that gathers at grain boundaries and improves cold workability by increasing the bonding strength of the grain boundaries. In order to obtain the above effect, it is necessary to contain 0.01% or more. However, if the content exceeds 0.40%, the saturation magnetic flux density and coercive force deteriorate, similar to Ti, Nb, and Ta.

(Example) Next, the features of the present invention will be clarified by comparing them with conventional alloys and comparative alloys through examples. Table 1 shows the chemical composition of the test gold.

(Left below) In Table 1, alloys 1 to 3 are the first invention, alloys 4 to 6 are the second invention, alloys 7 to 12 are the third invention, and alloys 13 to 18 are the fourth invention. Alloys 19-21 are comparison alloys and 2
Alloys 2 to 24 are conventional alloys, 22 is Fe-35%Co alloy, 23 is Fe-50%Co alloy, and 24 is Fe-49%C.
0-2%■ Alloy.

The test metals in Table 1 were melted in an electric furnace, hot rolled at 1200°C, held at 800°C for 1 hour, then water cooled for irregularization, and then cold rolled at 950°C. 2 hours at C (24
The alloy was magnetically annealed in a furnace after being held at 850°C for 4 hours. Table 2 shows the results of measuring the saturation magnetic flux density, coercive force, compressive deformation resistance, and limit processing rate using the test specimens produced under the above-mentioned production conditions.

For magnetic properties, a DC type BH tracer was used to prepare a ring test piece with an outer diameter of 24 mmφ, an inner diameter of 16 mmφ, and a thickness of 16 mm, and the saturation magnetic flux density and coercive force were measured.

Regarding compressive deformation resistance and limit processing rate, the diameter is 20 mm,
A cylindrical test piece with a height of 30 mm was prepared, and a tool with concentric circles in accordance with the standards of the Japan Society for Plasticity was used to
A test piece was subjected to compressive deformation using a 00 ton Amsler testing machine, and the processing load and the presence or absence of cracks during compression were measured. The values listed in Table 2 are the values obtained by dividing the processing load at a compression rate of 50% by the cross-sectional area calculated from the maximum diameter of the specimen at that time for the compression deformation resistance, and the values for the compression deformation resistance are the values for the compression deformation resistance. Tests were carried out up to 83%, and the test specimens with no cracks until the end were marked with ○, and the specimen specimens with cracks formed midway through were shown with the compression ratio at the time the cracks occurred.

(Left below) As is clear from Table 2, the comparative alloy No. 19 contained more Zr than necessary, so it had excellent cold workability but poor saturation magnetic flux density and coercive force. Yes, 2
Alloy 0 had poor saturation magnetic flux density and coercive force because C and N contained as impurities were not sufficiently removed during steelmaking, and alloy 21 had poor saturation magnetic flux density and coercive force because it contained more Si than necessary. As the density decreased, the transformation temperature also decreased, and the coercive force deteriorated.

On the other hand, the conventional alloy 22.23 alloy has Fe-
It corresponds to 35% Co alloy, Fe-50% Co alloy,
As mentioned above, since no ordered lattice suppressing elements are added to improve cold workability, the alloy is extremely brittle and has significantly poor cold workability. The corresponding alloy No. 24 is inferior in saturation magnetic flux density, coercive force, and cold workability.

Compared to these comparative alloys and conventional alloys, 1 to 18 of the present invention
The alloy has a saturation magnetic flux density of 24000G or more, coercive force],,
300. It has excellent magnetic properties as shown below, as well as excellent cold workability as compression deformation resistance of 92 kgf/mm" or less, and limit working rate of 83% or more.

(Effects of the Invention) As detailed above, the Fe-Co alloy of the present invention has
0.005 to 0 in Fe-Co alloy containing about 35%
．． Added 30% Zr, and further added Ti and N as necessary.
By adding a small amount of one or more of B, Ta, and B, conventional Fe-50%Co alloy, Fe-35
%Co alloy, it has significantly improved cold workability without impairing magnetic properties such as saturation magnetic flux density and coercive force, making it possible to manufacture thin plates by hoop rolling. Therefore, the present invention makes it possible to improve the performance, reduce the size and weight of magnetic circuits for electrical equipment, etc., and has high practicality in industry.

Claims (1)

[Claims] 1. Co: 33-37% by weight, Zr: 0.00
5 to 0.30%, C+N: 0.02% or less, and the remainder consists of Fe and impurity elements, and has excellent magnetic properties and cold workability. 2. Co: 33-37%, Zr: 0.00 in weight ratio
5 to 0.30%, C+N: 0.02% or less, further contains Si: 0.03 to 0.30%, and the balance is Fe.
and magnetic properties characterized by consisting of an impurity element,
Fe-C0 alloy with excellent cold workability. 3. Co: 33-37%, Zr: 0.00 in weight ratio
5 to 0.30%, C+N: 0.02% or less, further Ti: 0.005 to 0.30%, Nb: 0.005
~0.30%, Ta: 0.005~0.30%, B: 0
．． An Fe-Co alloy with excellent magnetic properties and cold workability, characterized by containing one or more of 01 to 0.40%, with the remainder consisting of Fe and impurity elements. 4. Co: 33-37%, Zr: 0.00 in weight ratio
5 to 0.30%, C+N: 0.02% or less, further Si: 0.03 to 0.30%, and Ti: 0.005%.
~0.30%, Nb:0.005~0.30%, Ta:
Magnetic properties and cold working characterized by containing one or more of 0.005 to 0.30%, B: 0.01 to 0.40%, and the remainder consisting of Fe and impurity elements. Fe-Co alloy with excellent properties.