JPH0762483A - Refining method of soft magnetic alloy - Google Patents

Abstract

PURPOSE:To obtain a soft magnetic alloy excellent in magnetic property by the production method suitable for mass-production with using a deoxidiser and slag making agent having low Ti and S content. CONSTITUTION:When the soft magnetic alloy containing, by weight, 35-50% Ni, <=15% Cr, and <=1.2% Al is produced, the deoxidizer and slaging agent with being reduced to <=0.05% Ti and <=0.05% S, are used so as to reduce to <=0.003% S. <=0.005% O, <=0.005% B and <=0.005% Ti under the condition of <=0.008(S+O+B). Cab, CaF, Al2O3, SiO2, etc., as the slaging agent are used with properly being combined. By this method, because there is scarcely a fine Ti inclusion, the growth of crystal line grain is not obstructed at magnetic annealing, the soft magnetic alloy with large magnetic permeability is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a soft magnetic alloy which is used as a magnetic head, a timepiece iron core, a magnetic shield member, etc. and which stably exhibits a high magnetic permeability.

[0002]

2. Description of the Related Art Fe-Ni soft magnetic alloys, so-called permalloys, are widely used for various soft magnetic applications including magnetic shield materials by utilizing their excellent magnetic properties. Typical materials belonging to this system are Mo and C
There is a high Ni permalloy (JIS-PC) containing r, Cu and the like. High Ni permalloy exhibits high magnetic permeability and high corrosion resistance, but it is an expensive material because it contains more than 70% by weight of Ni and Mo. Therefore, high Ni
The use of permalloy is subject to financial constraints. In consideration of economical efficiency, low Ni permalloy (JIS-PB) having a relatively low Ni content of about 45% by weight is used in place of expensive high Ni permalloy. Low Ni permalloy has a saturation magnetic flux density B ₁₀ of 15,000G
However, the effective magnetic permeability μ _e is extremely inferior to the high Ni permalloy. Therefore, high Ni permalloy is still unavoidable for applications requiring high soft magnetic properties. For these reasons, it has been desired to develop an inexpensive soft magnetic alloy having a magnetic characteristic comparable to that of high Ni permalloy and having low Ni permalloy or less. In order to meet this demand, the present inventors have developed a soft magnetic alloy having improved saturation magnetic flux density and effective magnetic permeability by containing Ni and Cr in specified ratios, and Japanese Patent Application No. 1-222745, Filed as Japanese Patent Application No. 2-78215.

[0003]

Problems to be Solved by the Invention High Ni permalloy (J
IS-PC), low Ni permalloy (JIS-PB), N
The magnetic properties of soft magnetic alloys such as i-Cr-Fe alloys are greatly affected by impurities such as S, O, and B. Above all, N
The magnetic properties of the i-Cr-Fe alloy are significantly deteriorated by impurities. Impurities are not limited to S, O and B,
Non-metallic inclusions mixed in from deoxidizing agents, slag forming agents, etc. may deteriorate the magnetic properties. Therefore, permalloy is usually manufactured by using a high-purity raw material and melting it in a vacuum induction melting furnace. This melting method increases the product cost because the raw material cost is high and it is not suitable for mass production.

By the way, the LD-VOD process is a method suitable for mass production, and is adopted on an industrial scale for producing stainless steel and the like. Scrap or the like can be used as a raw material, and high purification is achieved by refining, so that the manufacturing cost is reduced as compared with the vacuum induction melting method. However, even if the LD-VOD process is simply applied to the melting of the soft magnetic alloy, the obtained soft magnetic alloy is remarkably inferior in soft magnetic properties as compared with permalloy by the vacuum induction melting method using a high-purity raw material. There is. The present invention has been devised to solve such a problem, and by controlling the contents of Ti and S contained in deoxidizing agents, slag forming agents, etc., it is possible to produce soft magnetic alloys by melting. The purpose of the present invention is to enable the adoption of the LD-VOD process and manufacture a soft magnetic alloy having excellent magnetic properties with high mass productivity.

[0005]

In order to achieve the object, the melting method of the present invention is Ni: 35-50% by weight, C
When melting a soft magnetic alloy containing r: 15% by weight or less and Al: 1.2% by weight or less, Ti: 0.05% by weight or less and S: CaO, CaF reduced to 0.05% by weight or less
₂ , Al ₂ O ₃ , SiO _{2 and} other slag-forming agents were added to Ti: 0.0
5% by weight or less and S: 0.05% by weight or less of an Al-based deoxidizing agent is added in combination, and S + O + B: 0.008% by weight or less S: 0.003% by weight or less and O: 0.005% % And less, and B: 0.005% by weight or less and Ti: 0.005% by weight or less.

[0006]

The present inventors have obtained the following findings as a result of repeated studies on deterioration of soft magnetic properties of soft magnetic alloys. LD-
The soft magnetic alloy produced by the VOD process has a grain size of 0.
A large number of fine Ti-based inclusions of 1 μm or less, particularly Ti sulfides, are dispersed. The fine inclusions act as an inhibitor that inhibits the growth of crystal grains during magnetic annealing, and deteriorates the soft magnetic properties of the obtained soft magnetic alloy. Ti mixed in the soft magnetic alloy is Al added as a deoxidizing agent during melting of the alloy or Ca added as an auxiliary agent such as a desulfurizing agent or a slag forming agent.
It is derived from O, CaF ₂ , Al ₂ O ₃ , SiO _{2 and the} like. This is also confirmed from the fact that when refined with an Al-based deoxidizing agent or slag forming agent in which Ti and S are regulated, a soft magnetic alloy having high soft magnetic characteristics was produced even by the LD-VOD process. It was

As a result of repeated investigations and studies on the influence of Ti, in an alloy system containing Ni: 35 to 50% by weight, Cr: 15% by weight or less and Al: 1.2% by weight or less, T
i: 0.005 wt% or less, S: 0.003 wt% or less, O: 0.005 wt% or less, and S + O + B: 0.0
It has been found that a soft magnetic alloy exhibiting excellent soft magnetic characteristics can be obtained when the condition of 08% by weight or less is satisfied. This alloy contains CaO ,. A slag forming agent containing Ti: 0.05 wt% or less and S: 0.05 wt% or less, selected from CaF ₂ , Al ₂ O ₃ and SiO ₂ , is used: Ti: 0.05 wt% or less and S: 0. It is produced by complex addition with a deoxidizing agent of not more than 05% by weight.

The alloy components, contents, etc. specified in the present invention will be specifically described below. Ni: 35 to 50 wt% When the Ni content is less than 35 wt%, the magnetic permeability is low and a soft magnetic alloy having good soft magnetic properties cannot be obtained. But 50
If a large amount of Ni exceeding the weight percentage is contained, the alloy cost will increase. Cr: 15% by weight or less It is an important alloying element for improving magnetic permeability. But 1
On the contrary, when the Cr content exceeds 5% by weight, the magnetic permeability tends to decrease. Al: 1.2% by weight or less An alloying element that is inevitably mixed as a deoxidizer. Al
The greater the amount of contained, the greater the deoxidizing effect obtained, but
If the Al content exceeds 1.2% by weight, the magnetic permeability is reduced. Ti: 0.005% by weight It is an element which is extremely harmful to the soft magnetic properties, and even if a small amount of Ti is contained, the magnetic permeability remarkably decreases. Therefore, in the present invention, the Ti content is strictly limited to 0.005% by weight or less.

S, O, B: These impurities greatly reduce the magnetic permeability. To obtain a high magnetic permeability, S ≦
0.003% by weight, O ≦ 0.005% by weight, B ≦ 0.0
It is necessary to satisfy the conditions of 05% by weight and S + O + B ≦ 0.008% by weight. Deoxidizing agent and slag forming agent: When a soft magnetic alloy whose content of impurities is strictly controlled including Ti is melted by the LD-VOD process, impurities such as Ti and S mixed from the deoxidizing agent and slag forming agent Strict control of elements is required. In this respect, the Ti content contained in the deoxidizer and the slag-forming agent was set to 0.
The content of S was regulated to 05 wt% or less and the content of S was regulated to 0.05 wt% or less. Al or an Al alloy is used as the deoxidizer. Examples of the slag forming agent include CaO, CaF ₂ , Al ₂ O ₃ ,
SiO ₂ or the like is used.

[0010]

EXAMPLE Using the deoxidizing agent of Table 1 and the slag forming agent of Table 2, alloys having various compositions were melted by the LD-VOD process. Although the LD-VOD process is adopted in the present embodiment, it goes without saying that the present invention is similarly applied to other melting methods including the vacuum induction melting method. Table 3
Shows an alloy of group A with a composition satisfying the requirements specified in the present invention, together with the combination of deoxidizer and slag modifier used. On the other hand, Table 4 shows group B alloys whose compositions fall outside the ranges specified in the present invention, together with the combination of the deoxidizing agent and the slag forming agent used. Both Group A and Group B
Ti content used for melting stainless steel 0.0
Raw material scraps having an amount of 1% by weight or less and an S content of 0.01% by weight or less were melted using an arc melting furnace, and refined and the components were adjusted by an LD-VOD process. In addition, C listed in Table 4
Reference numeral 1 is an alloy obtained by vacuum induction melting a high-purity raw material.

[0011]

[Table 1]

[0012]

[Table 2]

[0013]

[Table 3]

[0014]

[Table 4]

Each of the melted alloys was hot-rolled and cold-rolled by a conventional method to produce a cold-rolled sheet having a sheet thickness of 0.5 mm.
A ring-shaped test piece for magnetic measurement was cut out from this cold-rolled sheet and subjected to magnetic annealing by heating at 1100 ° C. for 1 hour in a hydrogen atmosphere. Regarding the test piece after annealing, JIS C25
The magnetic measurement specified in No. 31 was performed.

[0016]

[Table 5]

[0017]

[Table 6]

As is clear from the comparison between Table 5 and Table 6 showing the measurement results, the alloys of group A which are the examples of the present invention used high-purity raw materials even by the LD-VOD process using scraps and the like. It can be seen that it exhibits excellent soft magnetic characteristics comparable to the vacuum induction melting material (C1). On the other hand, in the alloy B7-B11 obtained by using the auxiliary agent containing a relatively large amount of Ti, the content of impurities such as S, O, B and Ti does not satisfy the requirements of the present invention, and As shown in 6, the magnetic permeability was significantly reduced.

When the structure of each test piece was observed,
In the alloys of group A, precipitation of Ti-based inclusions was scarcely observed, and crystal grains were grown to a size of 200 μm or more by magnetic annealing. On the other hand, in the group B alloy, a large amount of fine Ti-based inclusions such as TiS having a grain size of 0.1 μm or less is deposited and the crystal grains after magnetic annealing are 50 μm.
It was nothing more than a degree. When the precipitation state and the crystal structure of the Ti-based inclusions are compared with the test results of Tables 5 and 6, as a result of the adverse effect of the Ti-based inclusions being suppressed, excellent soft magnetic properties are obtained in the alloy examples of the present invention. It is confirmed that it was obtained.

[0020]

INDUSTRIAL APPLICABILITY As described above, in the present invention, by reducing the contents of Ti and S contained in the deoxidizing agent and the slag forming agent, a vacuum induction melting material using a high purity raw material can be obtained. A soft magnetic alloy having comparable excellent magnetic properties can also be obtained by melting using scrap as a melting raw material. Therefore, when the soft magnetic alloy is manufactured by a melting method suitable for mass production such as the LD-VOD process, it is possible to reduce the manufacturing cost. Further, the melting method according to the present invention,
It can also be applied to the vacuum induction melting method, and by using the deoxidizing agent and the slag forming agent defined in the present invention, scraps other than high-purity raw materials can be used as melting raw materials.

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location C22C 38/00 303 SH01F 1/147 (72) Inventor Morihiro Hasegawa 4976 Nomuraminami-cho, Shinnanyo-shi, Yamaguchi Nisshin Steel Research Co., Ltd.

Claims (1)

[Claims] 1. When melting a soft magnetic alloy containing Ni: 35 to 50% by weight, Cr: 15% by weight or less and Al: 1.2% by weight or less, Ti: 0.05% by weight or less and S: 0.
CaO, CaF ₂ , Al ₂ O reduced to less than 05% by weight
₃ and SiO _{2 and} other slag forming agents are added in combination with Ti: 0.05 wt% or less and S: 0.05 wt% or less of Al-based deoxidizer, and S + O + B: 0.008 wt% or less S:
Deoxidizing and desulfurizing to 0.003 wt% or less and O: 0.005 wt% or less, and reducing to B: 0.005 wt% or less and Ti: 0.005 wt% or less. Alloy melting method.