JP2722520B2 - High permeability magnetic material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Industrial applications]

The present invention relates to a Fe—Ni-based magnetic alloy, particularly to a magnetic material having improved magnetic properties of PC permalloy.

[Prior art]

CP permalloy is preferably used as a material for forming a magnetic head core, a toroidal core, or a magnetic shielding material of various magnetic recording / reproducing devices. This material is optimal as an industrial material in that it has high magnetic permeability and good workability. Usually, in order to obtain excellent magnetic properties (especially magnetic permeability), after various types of processing, so-called magnetic annealing is performed, in which heating is performed at a high temperature to remove processing strain and increase the crystal grain size. At this time, increasing the crystal grain size is an important point for improving the magnetic permeability. On the other hand, as an attempt to improve the properties of Fe—Ni-based magnetic alloys, it has been proposed to add Ti or Zr together with carbon to form fine carbides. However, in this case, as characteristics, wear resistance and magnetic characteristics in a high frequency range are considered as problems, and improvement of DC magnetic characteristics is not intended. Rather,
It is generally accepted that the presence of the fine second phase lowers the DC magnetic properties. The present inventors conducted a study with the aim of improving the DC magnetic properties of a thin strip of PC permalloy, and as a result, by adding a small amount of a specific group of metals such as Ti, the crystal grains after magnetic annealing became coarse. Found the fact that

[Problems to be solved by the invention]

An object of the present invention is to provide a high-permeability magnetic material having a basic composition of PC permalloy and good DC magnetic characteristics by utilizing this new knowledge.

[Means for Solving the Problems]

The high-permeability magnetic material having improved direct-current magnetic properties according to the present invention has Ni: 65 to 90% as a main component, Mo: 7.0% or less, and Cu: 6.0%.
% Or less and Cr: 8.0% or less (Mo + Cu + Cr: 3.0 to 10.0%), in addition to Ti, Zr, Nb, Ta,
One or two selected from the group consisting of V and W
Species or more: 0.002 to less than 0.10%, and N: 0.02% or less, C: 0.1% or less, Mn: 1.0% or less, Si: 1.0% or less, Al:
0.05% or less and S: 0.02% or less, with the balance being substantially Fe
And an average crystal grain size of 0.25 mm or more. This alloy preferably further contains Mg: 0.05% or less.

[Operation]

As described above, since the present invention relates to the improvement of PC permalloy, the basic alloy composition follows that of PC permalloy. Therefore, the function of the basic alloy components and the reason for limiting the composition thereof will be understood. However, the following will be explained together with the other components. Ni: 65-90% To obtain high magnetic properties required for permalloy,
Make up at least 65%. In terms of cost, the higher the Ni content, the more disadvantageous. If it exceeds 90%, the Fe content inevitably decreases, causing a decrease in saturation magnetization and a decrease in magnetic permeability. A range of 75-85% is preferred. Mo: 7.0% or less Cu: 6.0% or less Cr: 8.0% or less (However, Mo + Cu + Cr: 3.0 to 10.0%) All of these elements are components for ensuring high magnetic permeability in the alloy of the present invention. Alternatively, it is necessary to add two or more kinds in a total amount of 3.0% or more in the case of two or more kinds. The use of Cr also helps improve corrosion resistance. Addition exceeding 10.0% lowers the saturation magnetization and lowers the magnetic permeability to impair the magnetic properties, and also causes a reduction in cold workability such as punching and deep squeezing. One or more of Ti, Zr, Nb, Ta, V and W: 0.002 or more
Less than 0.10% These elements have the effect of refining crystal grains when added in a relatively large amount, which is known as described above, but when present in a relatively small amount, rather increases the crystal grains. . This effect can be obtained by adding 0.002% or more,
If it is less than%, it will be lost. The presence of a relatively large amount is also negative for hot workability. N: 0.02% or less A nitride is formed together with Ti, Zr, Nb, Ta, and W, and has an effect of crystal grain coarsening. However, if it exceeds 0.01%, there is a danger of blowholes occurring, so the limit is 0.02%. C: 0.1% or less It is inevitable to mix slightly from the raw material, but from the viewpoint of magnetic properties, we want to reduce it as much as possible, and the allowable limit is 1.0%. Mn: 1.0% or less In addition to a deoxidizing effect, a small amount is preferable because it enhances magnetic properties and improves hot workability. However, if it exceeds 1.0%, it becomes rather negative. Si: 1.0% or less It is used as a deoxidizing agent. However, if it is contained in a large amount, the magnetic permeability is lowered. Al: 0.05% or less Although the deoxidizing effect is high, if the amount is large, it becomes an inclusion and deteriorates the magnetic properties. Regulation of S, and addition of Mg in a preferred embodiment,
For the following reasons. S: 0.02% or less To maintain good hot workability, reduce S as much as possible. There is practically no adverse effect within the above 0.02% limit. Mg: 0.05% or less The presence of a small amount helps to improve hot workability. The addition of Mg is preferable because the influence of the unavoidable trace amount of S is relieved. If it exceeds 0.05%, the magnetic properties will be inferior. The requirement that the average crystal grain size be 0.25 mm or more is based on the finding that the larger the crystal grain size is, the more the DC magnetic properties are improved, and that the effect can be ensured if the grain size is 0.25 mm or more. By setting the hardness before annealing to Vickers hardness (Hv) of 350 or more, the crystal grain size after annealing can easily take a value of 0.25 mm or more.

【Example】

Alloys having the compositions shown in Table 1 were melted using a vacuum induction melting furnace, and ingots of 50 kg each were cast. After casting each test material hot to make a 30mm thick plate,
Hot rolling and cold rolling were performed to obtain strips having various thicknesses shown in Table 2. At this time, the height (Hv) was adjusted by selecting the cold working ratio. In order to see the tendency of hot workability, a sample was cut out from a 30 mm thick plate by machining for some test materials,
A hot torsion test was performed. The result is shown in the drawing. Heat the strip to 1100 ° C in a hydrogen stream and hold for 2 hours.
Magnetic annealing was performed at a cooling rate of 150 ° C./hr to determine the crystal grain size and to measure the maximum magnetic permeability as a representative of the magnetic properties. The crystal grain size was measured on the surface of the strip by microscopic observation. Table 2 summarizes the above results.

【The invention's effect】

The magnetic material of the present invention is one in which the properties of PC permalloy are improved. In various magnetic heads and cores, permalloy tends to be used as a thinner plate, and the present invention can provide a magnetic material having good characteristics in response thereto.

[Brief description of the drawings]

The drawing is a graph of the breaking toughness value measured as an index of hot workability in Examples of the present invention.

Claims (3)

(57) [Claims] 1. One or two or more of Ni: 65 to 90% as a main component, Mo: 7.0% or less, Cu: 6.0% or less, and Cr: 8.0% or less (however, Mo + Cu + Cr: 3.0 to 10.0%) Plus T
1 selected from the group consisting of i, Zr, Nb, Ta, V and W
Species or two or more: 0.002 to less than 0.10%, and N: 0.01
%: C: 0.1% or less, Mn: 1.0% or less, Si: 1.0%
% Or less, Al: 0.05% or less and S: 0.02% or less, the balance being substantially an alloy composition consisting of Fe,
High magnetic permeability magnetic material characterized by being 0.25 mm or more. 2. The magnetic material according to claim 1, wherein an alloy containing Mg: 0.05% or less in said composition is used. 3. The hardness before magnetic annealing is Vickers hardness (Hv).
3. The magnetic material according to claim 1 or 2, wherein