JPH08100244A - Soft magnetic meterial - Google Patents

Abstract

PURPOSE: To obtain a material having high saturation magnetic flux density, increased in specific resistivity, and excellent in workability and machinability by specifying respective contents of C, Si, Mn, P, S, Cu+Ni, Mo, Al, N, and O in a soft magnetic material. CONSTITUTION: This soft magnetic material has a composition containing, as essential components, <=0.01% C, <=6.00% Si, <=0.50% Mn, <=0.010% P, <=0.015% S, <=0.15% (Cu+Ni), <=2.0% Mo, 0.03-6.00% Al, <=0.100% N, and <=0.005% O and having the balance Fe with inevitable impurities and satisfying Si+Al<=6.00% and C+N<=0.015%. Because characteristics of >=1.5T B240 , <=50A/m Hc, and >=40μΩ.cm (ρ) are simultaneously provided, this soft magnetic material has superior pulse responsiveness, and moreover, it has >=10% elongation percentage for evaluating cold workability. Prescribed amounts of one or >=2 elements among Pb, Bi, Ca, Te, and Ce are incorporated into this magnetic material, if necessary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft magnetic material, and more specifically, it has a high saturation magnetic flux density (Bs), a large specific resistance (ρ), and good workability and machinability. The present invention relates to a soft magnetic material useful as a material for an injection pump.

[0002]

2. Description of the Related Art For example, a solenoid valve of a fuel injection pump for an automobile has a structure in which a connector portion of an electromagnet and a valve body is housed in a housing, and an electromagnetic force is generated by applying a magnetic pulse to the electromagnet. The valve element is excited to attract the valve element, and the application of the magnetic pulse is released to demagnetize the electromagnetic force to separate the valve element to perform the valve function.

Incidentally, the solenoid valve is required to have the following characteristics in relation to the above-mentioned valve function. That is,
When a magnetic pulse is applied to the solenoid valve, the electromagnet quickly attracts the valve body without showing a time delay and with a large force, and when the application of the magnetic pulse is released, the valve body is quickly separated. That is. That is, the pulse response is excellent.

This pulse response is defined by the magnetic properties of the material forming the solenoid valve. Specifically, a material having a high magnetic flux density and a material having a high specific resistance have excellent magnetic rising characteristics when a magnetic pulse is applied, and exhibit a large attractive force with the valve body. Further, a material having a low coercive force (Hc) or a material having a large specific resistance has an excellent magnetic falling characteristic when the magnetic pulse is released,
The valve element can be quickly separated.

Therefore, in order to improve the pulse response of the solenoid valve, a material having a high magnetic flux density and a high specific resistance and a low coercive force should be selected as a material to be used. Further, since the solenoid valve is processed into a desired shape by subjecting a predetermined material to, for example, cold forging or cutting, the material used is required to be a material with good manufacturability.

Conventionally, as such an electromagnetic valve material, for example, 3% silicon steel or 13% Cr-Fe having corrosion resistance is used.
Stainless steel, 18% Cr-Fe stainless steel, etc. are used.

[0007]

By the way, recently, there has been an increasing demand for making the valve operation of the solenoid valve quick and making the overall shape smaller. Then, in order to satisfy the former requirement, when the application of the magnetic pulse is released, for example, a spring component such as a spring component is provided between the electromagnet and the valve body for the purpose of quickly separating the attracted valve body from the electromagnet. An intervening force separation means is used.

Therefore, when a magnetic pulse is applied, not only the pulse response is good, but also the magnetic flux density capable of quickly attracting the valve body by overcoming the elastic force of the separating means is excited. It is necessary to construct the solenoid valve with the material. That is, it is necessary to use a material having a higher saturation magnetic flux density than ever before.

Further, when the solenoid valve is made of a material having a high saturation magnetic flux density, the attraction force to the valve body generated at the time of the magnetic rising also becomes large. Therefore, even if the shape of the electromagnet is smaller than the conventional one, the valve operation equivalent to the conventional one can be realized. That is, using a material having a high saturation magnetic flux density is also a way to meet the demand for miniaturization of the solenoid valve.

The above-mentioned materials known in the related art all have a magnetic flux density (B ₂₄₀ ) of about 1.3 Tesla (T) when a magnetic field of 240 A / m is applied, and a specific resistance (ρ Is about 70 μΩ · cm, which cannot fully meet the above-mentioned requirements, and its improvement is desired. The present invention solves the above-mentioned problems in the conventional soft magnetic material, B ₂₄₀ is 1.5 T or more, ρ is 40 μΩ · cm or more, H
An object of the present invention is to provide a soft magnetic material having c of 50 A / m or less and having good cold workability and machinability.

[0011]

In order to achieve the above object, in the present invention, C: 0.01% by weight or less, S
i: 6.00% by weight or less, Mn: 0.50% by weight or less, P:
0.010% by weight or less, S: 0.015% by weight or less, total amount of Cu and Ni: 0.15% by weight or less, Mo: 2.0% by weight or less, Al: 0.03 to 6.00% by weight , N: 0.010% by weight
Below, O: 0.005% by weight or less is essential, and Si
And Al: 6.00% by weight or less, C and N: 0.0
There is provided a soft magnetic material (hereinafter, referred to as a first material) characterized by satisfying 15% by weight and the balance consisting of Fe and inevitable impurities.

In the present invention, C: 0.01% by weight or less, Si: 6.00% by weight or less, Mn: 0.50% by weight.
Hereinafter, P: 0.020% by weight or less, S: 0.015% by weight or less, total amount of Cu and Ni: 0.15% by weight or less, Mo: 2.0
Weight% or less, Al: 0.03 to 6.00% by weight, N: 0.01
5% by weight or less, O: 0.005% by weight or less, B: 0.000
5 to 0.010% by weight, Ti: 0.005 to 0.10% by weight are essential, and the total amount of Si and Al: 6.00% by weight or less, the total amount of C and N: 0.020% by weight % Or less, Ti: N 3
There is provided a soft magnetic material (hereinafter referred to as a second material) characterized by satisfying a multiple value or more and the balance consisting of Fe and inevitable impurities.

In the first material, C is contained as an impurity during melting, but if the content is too large, B ₂₄₀
Of the magnetic properties and deterioration of the magnetic properties such as an increase in the coercive force (Hc), and the pulse response is also deteriorated. Therefore, the upper limit value is limited to 0.010% by weight. Preferably 0.
It is 005% by weight or less. Si has the effect of increasing pulse response and decreasing Hc as the content thereof increases. However, if the content is too large, the deformation resistance during cold working of the material increases and the material becomes brittle, so the upper limit is made 6.00% by weight. It is preferably 1.0 to 4.0% by weight.

Mn is added as a deoxidizing element during melting.
However, if too much is included, Si and
It also reduces the cold workability of the material, so
The limit value is 0.50% by weight. Preferably 0.30% by weight or less
Below. P is contained as an impurity during melting,
If it is contained too much, B ₂₄₀Decrease and Hc increase
Deterioration of magnetic characteristics such as addition, pulse response
Also deteriorates the cold workability.
Therefore, the upper limit is 0.010% by weight. Preferably
Is 0.005% by weight or less.

S is also contained as an impurity during melting, but if it is contained in a too large amount, it causes deterioration of magnetic characteristics such as a decrease in B ₂₄₀ and an increase in Hc, and the pulse response becomes worse. Since the cold workability also decreases, the upper limit value is made 0.015% by weight. Preferably 0.00
It is 5% by weight or less. Both Cu and Ni are contained as impurities at the time of melting, but the higher the content, the worse the magnetic characteristics and the poorer the pulse response. Therefore, the upper limit is 0 in the total amount of both. 0.15% by weight.
Preferably, the total amount is 0.10% by weight or less.

Mo is a component that contributes to the improvement of corrosion resistance, but if it is contained too much, cold workability is deteriorated, so the upper limit is made 2.0% by weight. It is preferably 1.0% by weight or less. Al is a component that behaves similarly to Si. That is, as the content increases, ρ increases and Hc decreases, and the magnetic characteristics improve. If the content is too small, the above effects are not exhibited, and if it is too large, the cold workability is deteriorated. Therefore, the content is set in the range of 0.03 to 6.00% by weight. Preferably, it is 0.03 to 5.0% by weight.

N is contained as an impurity during smelting. However, if the content of N increases, the magnetic properties deteriorate, such as a decrease in B ₂₄₀ and an increase in Hc, so the upper limit of the content is N.
It is regulated to 0.010% by weight. It is preferably 0.005% by weight or less. When the content of O increases, the amount of oxide-based non-metallic inclusions generated with other components increases, which hinders the movement of the magnetic domain wall, and increases the Hc, thereby increasing the magnetic characteristics required for the valve operation of the solenoid valve. In addition to deteriorating, the workability is deteriorated, so the content is regulated to 0.005% by weight or less. It is preferably 0.004% by weight or less.

In the case of the first material, among the above components, the total amount of Si and Al is 6.00 wt% or less, and the total amount of C and N is 0.015 wt% or less. Must be contained in. The total amount of Si and Al is 6.00
If the amount is more than 10% by weight, the cold workability of the material is deteriorated. If the total amount of C and N is more than 0.015% by weight, the magnetic properties are deteriorated and the cold workability is deteriorated. is there.

The first material may contain Cr. Cr functions to improve the corrosion resistance of the material, but if it is contained too much, it causes a decrease in B ₂₄₀ , so the content is regulated to 0.1% by weight or less.
Further, in order to improve the machinability, P is added to the first material.
One or two free cutting elements such as b, Bi, Ca, Te, and Se may be contained.

In this case, if the content is too small, the above-mentioned effect is not exhibited, and if it is too large, the toughness is deteriorated. Therefore, in the case of Pb, 0.03 to 0.30% by weight, B
0.002 to 0.20% by weight for i, 0.0 for Ca
It is preferably set to 02 to 0.20% by weight, 0.01 to 0.20% by weight for Te, and 0.03 to 0.30% by weight for Se.

Next, the second material has, in addition to the components of the first material, B: 0.0005 to 0.010 as a component.
%, Ti: 0.005 to 0.10% by weight, P
Content of 0.020% by weight or less, N content of 0.015
It is characterized in that the content of C and N is regulated to not more than wt%, the total amount of C and N is regulated to not more than 0.020 wt%, and the content of Ti is set to be not less than 3 times the value of N.

Here, B functions to coarsen the crystal grains in the material to increase the B ₂₄₀ of the material and to lower the Hc. This sharpens the magnetic rising characteristics of the material and also sharpens the magnetic falling characteristics.
If the content of B is too small, the above effects are not sufficiently exhibited, and if it is too large, the hot workability and toughness of the material are deteriorated, so the content is 0.0005 to 0.
It is set in the range of 010% by weight.

Ti is a component that functions to prevent impurities such as N, C and P from binding to the above-mentioned B and diminishing the effective function of B. Its function is that the content is N
Is effectively exhibited when the content is 3 times the value of
When the value is less than the double value, N that is not fixed by Ti bonds with B described above to suppress coarsening of crystal grains and cause deterioration of magnetic properties. However, if too much Ti is contained, the cold workability of the material is deteriorated, so the content is set in the range of 0.005 to 0.10% by weight.

With respect to the addition of B and Ti, in the case of the second material, the upper limits of the P content, the N content, and the total content of C and N are set to the first material. It can be set higher than the case. Also, for this second material,
As with the first material, a free-cutting element can be added to enhance its machinability. In that case, for the same reason as in the case of the first material, Pb, Bi, Ca, Te, Se
Respectively 0.03 to 0.30% by weight, 0.002 to 0.2
It is preferable to contain 0% by weight, 0.002 to 0.20% by weight, 0.01 to 0.20% by weight, and 0.03 to 0.30.

Further, the second material may contain Cr, and in that case, the content is regulated to 0.1% by weight or less for the same reason as in the case of the first material. Is preferred.

[0026]

Since the soft magnetic material of the present invention has the above composition, B ₂₄₀ is 1.5 T or more, ρ is 40 μΩ · cm or more,
The material simultaneously satisfies the characteristics of Hc of 50 A / m or less and elongation of 10% or more. Therefore, it has excellent pulse responsiveness, particularly both magnetic rising characteristics and magnetic falling characteristics, and exhibits extremely excellent responsiveness when used as a material for a solenoid valve.

[0027]

Examples of the invention

 Examples 1 to 10 and Comparative Examples 1 to 5 Various materials having the compositions shown in Table 1 were melted.

[0028]

[Table 1]

These materials were rolled into a round bar having a diameter of 38 mm and further annealed at a temperature of 750 ° C. By machining these materials, a magnetic ring test piece with an outer diameter of 35 mm, an inner diameter of 25 mm, and a thickness of 7 mm, a diameter of 5 mm, a length of 100 mm, a volume resistivity measuring test piece, and a tensile test part with a diameter of 8 mm and a length of 34 mm were obtained. Each tensile test piece was produced.

After vacuum-annealing these test pieces at 850 ° C. for 2 hours, magnetic properties such as B ₂₄₀ , Hc, ρ and pulse responsiveness were confirmed, and cold workability was confirmed by elongation in a tensile test. Was evaluated. The pulse response is obtained by winding a primary coil and a secondary coil around a magnetic ring test piece and applying a 100 Hz magnetic pulse to the primary coil for one cycle of 5 msec on-5 msec off. It is shown as the time (msec) until the magnetic flux density obtained by integrating the current value from 1 to 90% of the saturation magnetic flux density is reached. The shorter this time is, the better the magnetic rising characteristics of the material and the better the pulse response.

Further, when a hole having a depth of 5 mm is drilled using a drill having a diameter of 2 mm in these materials, and 81 or more holes can be drilled, rank A, 51 to 80 holes are drilled. When it is possible, it is ranked B, and when it is possible to drill 21 to 50 holes, it is rated C
When the rank and the number of drilled holes were 20 or less, the rank D was evaluated, and the machinability of the material was evaluated. The above results are collectively shown in Table 2.

[0032]

[Table 2]

As is clear from Tables 1 and 2, Si is 6.
The total amount of Si and Al is 6.14% by weight and 6.00% at 09% by weight.
Exceeding wt%, O is 0.010 wt% and 0.0005 wt%
The material of Comparative Example 1 having a value of more than 1.0 has a good pulse response, but has a low B ₂₄₀ , a small elongation and a poor cold workability. Further, as in the material of Comparative Example 2, when Al is less than 0.01% by weight and 0.03% by weight, B ₂₄₀ and elongation increase, but the specific resistance decreases and the pulse response deteriorates. .

The total amount of Si and Al is 6.03% by weight and 6.00
The material of Comparative Example 3 in which the content exceeds 5% by weight has a large specific resistance and a good pulse response, but the B ₂₄₀ does not reach 1.5T, the elongation is small, and the cold workability is poor. Furthermore, C
And the total amount of N exceeds 0.016% by weight and 0.015% by weight,
Mo is 0.21% by weight and exceeds 0.2% by weight, and Ti is 0.2% by weight.
The material of Comparative Example 4 in which the content of 15% by weight and the content of 0.10% by weight exceeded B ₂₄₀ did not reach 1.5T, and Hc was too large, resulting in poor pulse response.

C and N are both 0.015% by weight.
The total amount of C and N exceeds 0.010% by weight and 0.030% by weight
And the material of Comparative Example 5 in which the amount exceeds 0.015% by weight,
₂₄₀ does not reach 1.5T and Hc is too large, resulting in poor pulse response. On the other hand, in all the materials of the present invention, B ₂₄₀ is 1.5 T or more, Hc is 50 A / m or less, ρ
Has a pulse response of 40 μΩ · cm or more, an elongation of 10% or more, and machinability all belong to rank A or rank B. Particularly, when a free-cutting element is added, it exhibits extremely excellent machinability.

[0036]

As is apparent from the above description, the soft magnetic material of the present invention has B ₂₄₀ of 1.5 T or more and Hc of 50 A /
Since it simultaneously satisfies the characteristics of m or less and ρ of 40 μΩ · cm or more, its pulse response is excellent. Moreover, the elongation at which the cold workability can be evaluated is 10% or more, and the machinability is excellent.

Therefore, the material of the present invention has a high industrial value as an electromagnetic valve material for an electromagnetic fuel injection pump, which requires a quick pulse response and a large suction force, and further realizes miniaturization of the electromagnetic valve. It is also a useful soft magnetic material.

Claims (4)

[Claims] 1. C: 0.01 wt% or less, Si: 6.00 wt% or less, Mn: 0.50 wt% or less, P: 0.010 wt% or less, S: 0.015 wt% or less, Total amount of Cu and Ni:
0.15% by weight or less, Mo: 2.0% by weight or less, Al: 0.0
3 to 6.00% by weight, N: 0.010% by weight or less, O: 0.0
05 wt% or less is essential and the total amount of Si and Al:
A soft magnetic material, which satisfies 6.00% by weight or less, the total amount of C and N: 0.015% by weight, and the balance is Fe and inevitable impurities. 2. Further, Pb: 0.03 to 0.30% by weight, B
i: 0.002 to 0.20% by weight, Ca: 0.002 to 0.20
% By weight, Te: 0.01 to 0.20% by weight, Se: 0.03 to
3. The soft magnetic material according to claim 1 or 2, which contains 0.30% by weight of one kind or two or more kinds. 3. C: 0.01 wt% or less, Si: 6.00 wt% or less, Mn: 0.50 wt% or less, P: 0.020 wt% or less, S: 0.015 wt% or less, Total amount of Cu and Ni:
0.15% by weight or less, Mo: 2.0% by weight or less, Al: 0.0
3 to 6.00% by weight, N: 0.015% by weight or less, O: 0.0
05% by weight or less, B: 0.0005 to 0.010% by weight, T
i: 0.005 to 0.10 wt% is essential, and the total amount of Si and Al: 6.00 wt% or less, the total amount of C and N: 0.02
A soft magnetic material characterized by satisfying 0% by weight or less and a triple value of Ti: N or more, and the balance being Fe and inevitable impurities. 4. Pb: 0.03 to 0.30% by weight, B
i: 0.002 to 0.20% by weight, Ca: 0.002 to 0.20
% By weight, Te: 0.01 to 0.20% by weight, Se: 0.03 to
6. The soft magnetic material according to claim 4 or 5, which contains 0.3% by weight of one kind or two or more kinds.