JPH0236663B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on HADFIELD'S AUSTENITIC
This invention relates to improvements in the Fe-Mn-C alloy known under the name STEEL.

HADFIELD'S AUSTENITIC STEEL is an alloy with a composition consisting of appropriate amounts of Mn and C and the balance iron, and it is easily possible to introduce a non-magnetic austenite phase (hereinafter referred to as γ phase) at room temperature. This is a material in which martensitic transformation (γ phase → martensitic phase (hereinafter referred to as α phase)) hardly occurs during processing. Furthermore, when this alloy is subjected to cold working in the γ phase state, it undergoes significant work hardening and increases its mechanical strength. However, when an attempt is made to form the ferromagnetic α phase in the γ phase matrix by heat treatment, the γ phase is stable at low temperatures, so γ→
In order for the α1 transformation to not occur and for the γ→α transformation to be completely completed, a long heat treatment is required. The reason why the long heat treatment is required is that appropriate amounts of Mn and C are added, and the effect of C is particularly large. This alloy forms a mixed phase of α+γ+Fe ₃ C or γ+Fe ₃ C between the α phase and γ phase, and moreover, Fe ₃ C
are strongly connected.

As described above, this alloy has the advantage that the γ phase can be easily introduced at room temperature, but when considering its application to magnetic materials, it has the disadvantage of requiring a long heat treatment for the γ→α transformation. There is.

The present invention provides a composite magnetic material characterized in that H _f is added to the above alloy in order to easily transform the γ phase of the above alloy into the α phase by heat treatment for a short time. This is an alloy for materials, which takes advantage of the advantages of the above alloys and solves the drawbacks mentioned above to provide an alloy for composite magnetic materials that is industrially effective, has a wide range of applications, and is excellent in terms of productivity. .

According to the alloy for composite magnetic materials of the present invention, by annealing the material using a laser beam, an electron beam, an infrared beam, etc., the surface of a non-magnetic material can be formed at an arbitrary depth and in an arbitrary pattern. It became possible to form a magnetic phase. Furthermore, compared to a composite magnetic material that is made by joining a non-magnetic material and a magnetic material together using an adhesive, mechanical method, thermocompression bonding, etc., the composite magnetic material manufactured by the method of the present invention has mechanical reliability. It was also found that they are superior in terms of sex.

The reason for limiting the range of chemical components of the alloy for composite magnetic material in the present invention will be described below.

Fe is the main component of the alloy for composite magnetic material in the present invention. The γ phase of Fe is unstable and transforms into the α phase during the cooling process, no matter how quickly it is cooled.

The γ phase of Fe is formed by solid solution of C up to about 2% by weight.
− region is formed and becomes stable, but when rapidly cooled from high temperature, γ
In order to bring the phase to room temperature, more than 2% by weight of
Mn had to be added. On the other hand, in order to obtain an alloy with a practically sufficient amount of magnetization,
Mn must not be added in excess of 20% by weight, and the maximum
When 20% by weight of Mn was added, the γ phase could be easily introduced at room temperature by adding 0.4% by weight or more of C. If more than 2% by weight of C is added, all the added C will not be solidly dissolved and will be incorporated into the matrix of the γ phase.
A compound in which Mn, Hf, or Fe and C are bonded coexists, and a single γ phase cannot be obtained at room temperature. Therefore, the alloy for composite magnetic materials of the present invention containing more than 2% by weight of C is difficult to cold-work such as rolling, wire drawing or swaging at room temperature.

The alloy having the above composition range can be rapidly cooled to introduce the γ phase to room temperature, but 0.1 to 2.5% by weight of _Hf was added to facilitate the γ→α transformation.
When the amount added is less than 0.1% by weight, the effect of _Hf addition is not exhibited, and when it is added more than 2.5% by weight, it becomes α phase in the entire temperature range.

Next, the details of the present invention will be explained by listing examples.

Example 1 An alloy ingot having a composition of (Fe _85.8 Mn ₁₃ C _1.2 ) _98.3 H _f1.7 in weight % was heated at a temperature of 1100° C. for 1 hour.
After homogenization treatment in an Ar atmosphere, it was immersed in a 10% NaOH aqueous solution and rapidly cooled. When a small piece was cut out from this alloy ingot and the amount of magnetization was measured, σs = 0.02
(emu/gm). After removing the surface oxide film of this alloy ingot, it was cold rolled with an area reduction rate of 50%, and the magnetization amount was σs = 0.05.
It became (emu/gm). Furthermore, when this alloy ingot was further cold-rolled with an area reduction of 99% from its initial shape, the magnetization amount was σs = 0.1 (emu/
gm). Also, mechanical strength σ _0.2 = 142Kg/
mm ² , and the Vickers hardness Hv=741.

A 50 μm thick γ-phase plate material cold-rolled as described above was annealed at 550° C. for 5 seconds in an Ar atmosphere, and then rapidly cooled in an Ar atmosphere. the result,
Magnetization amount σs = 120 (emu/gm), mechanical strength σ _0.2 = 85
(Kg/gm ² ), with a Bitkers hardness of Hv=505.Also, the surface of the 50μm thick γ-phase plate material was treated with a 3W continuous wave YAG laser annealing device.
Annealing was performed in an Ar atmosphere by running a laser beam with a diameter of mm at a speed of 1 (mm/sec.). When the heated part was observed under a microscope, it was confirmed that it had transformed into a phase different from the γ phase in a width of approximately 1.1 mm over the entire length in the thickness direction, and the phase-transformed part was cut out and the magnetization amount was determined. When measured, it was found to be an α phase with σs=110 (emu/gm).

Example 2 An alloy ingot having a composition of (Fe ₉₆ Mn ₂ C _2.0 ) _97.5 H _f2.5 in weight % was heated at a temperature of 1100° C. for 1 hour.
After homogenization treatment in an Ar atmosphere, it was immersed in a 10% NaOH aqueous solution and rapidly cooled. When a small piece was cut out from this alloy ingot and the amount of magnetization was measured, σs = 0.03
(emu/gm). After removing the surface oxide film of this alloy ingot, it was cold rolled with an area reduction rate of 99%, and the magnetization amount σs = 0.3
It became (emu/gm). Also, mechanical strength σ _0.2 = 130
Kg/mm ² and Bitkers hardness Hv=639.

A 50 μm thick γ-phase plate material cold-rolled as described above was annealed at 600° C. for 5 seconds in an Ar atmosphere, and then rapidly cooled in an Ar atmosphere. the result,
Magnetization amount σs = 135 (emu/gm), mechanical strength σ _0.2 = 82
(Kg/mm ² ), and the Bitkers hardness was Hv=495.

In addition, the surface of the γ phase plate material with a thickness of 50 μm was
1 with 3.5W continuous wave YAG laser annealing equipment
Annealing was performed in an Ar atmosphere by running a laser beam with a diameter of mm at a speed of 1.5 (mm/sec). When the heated part was observed under a microscope, it was confirmed that it had transformed into a phase different from the γ phase in a width of approximately 1.1 mm over the entire length in the thickness direction, and this phase-transformed part was cut out. When we measured the amount of magnetization, σs = 124 (emu/
gm).

Example 3 An alloy ingot having a chemical composition of (Fe _79.6 Mn ₂₀ C _0.4 ) _99.9 H _f0.1 in weight% was homogenized in an Ar atmosphere at a temperature of 1100°C for 1 hour, and then placed in a 10% NaOH aqueous solution. It was soaked in water and quenched. Cutting out a small piece from this alloy ingot and measuring the amount of magnetization, σs = 0.03
(emu/gm). After removing the surface oxide film of this alloy ingot, it was cold rolled with an area reduction rate of 99%, and the magnetization amount σs = 0.2
It became (emu/gm). Also, mechanical strength σ _0.2 = 119
(Kg/mm ² ), and the Bitkers hardness Hv was 593.

A 50 μm thick γ-phase plate material cold-rolled as described above was annealed at 500° C. for 5 seconds in an Ar atmosphere, and then rapidly cooled in an Ar atmosphere. the result,
Magnetization amount σs = 109 (emu/gm), mechanical strength σ _0.2 = 76
(Kg/mm ² ), and became an α phase with a Bitkers hardness of Hv=486.

In addition, the surface of the γ phase plate material with a thickness of 50 μm was
1 with 2.5W continuous wave YAG laser annealing equipment
Annealing was performed in an Ar atmosphere by running a laser beam with a diameter of mm at a speed of 1 (mm/sec). When the heated part was observed under a microscope, it was confirmed that it had transformed into a phase different from the γ phase in a width of approximately 1.1 mm over the entire length in the thickness direction, and this phase-transformed part was cut out. When we measured the amount of magnetization, σs = 98 (emu/
gm).

Example 4 The alloy ingot used in Example 1 was homogenized at a temperature of 1100°C for 1 hour in an Ar atmosphere, and then 10%
It was quenched by immersing it in a NaOH aqueous solution. When a small piece was cut out from this alloy ingot and the amount of magnetization was measured, it was found to be a γ phase with σs = 0.02 (emu/gm). After removing the surface oxide film of this alloy ingot, it was cold-rolled with an area reduction of 99% to form a plate material with a thickness of 50 μm. This plate was heated with Ar at a temperature of 950℃ for 5 seconds.
It was heat treated in an atmosphere and rapidly cooled in an Ar atmosphere.
As a result, magnetization amount σs = 0.02 (emu/gm), mechanical speed σ _0.2 = 55 (Kg/mm ² ), and Bitkers hardness Hv = 273
It was hot.

The above heat-treated 50 μm thick γ-phase plate material
Annealed in an Ar atmosphere at a temperature of 550℃ for 5 seconds,
It was quenched in an Ar atmosphere. As a result, the amount of magnetization σs=
110 (emu/gm), mechanical strength σ _0.2 = 70 (Kg/mm ² ),
It became an α phase with a Bitkers hardness of Hv=404.

In addition, the surface of the above 50 μm thick γ-phase plate material was coated with a 3W continuous wave YAG laser annealing device.
Annealing was performed in an Ar atmosphere by running a laser beam with a diameter of 1 mm at a speed of 1 (mm/sec.). When the heated part was observed under a microscope, it was confirmed that the entire length in the thickness direction was transformed into a phase different from the γ phase in a width of about 1 mm.This phase transformed part was cut out and the amount of magnetization was determined. When we measured σs=100(emu/
gm).

Example 5 An alloy ingot having the composition used in Example 1 was
After homogenization treatment at a temperature of 1 hour in an Ar atmosphere at a temperature of °C, it was quenched by immersing it in a 10% NaOH aqueous solution.
When a small piece was cut out from this alloy ingot and the amount of magnetization was measured, it was found to be a γ phase with σs = 0.02 (emu/gm). After removing the surface oxide film of this alloy ingot, it was subjected to cold rolling with an area reduction rate of 75%, and after being homogenized again at a temperature of 950°C for 30 minutes in an Ar atmosphere, it was placed in the above solution. Soaked and cooled quickly. As a result, the magnetization amount is σs=0.02(emu/
gm). Subsequently, cold rolling was performed again with an area reduction rate of 50% to obtain a plate material with a thickness of 30 μm.
As a result, magnetization σs = 0.055 (emu/gm), mechanical strength σ _0.2 = 122 (Kg/mm ² ), and Vickers hardness Hv = 670.
It was hot.

The above cold-rolled plate material with a thickness of 30 μm is
Annealed in an Ar atmosphere at a temperature of 550℃ for 5 seconds,
It was rapidly cooled in an Ar atmosphere. As a result, the amount of magnetization σs = 118
(emu/gm), mechanical strength σ _0.2 = 82 (Kg/mm ² ), and Vickers hardness Hv = 497.

In addition, the surface of the 30 μm thick γ-phase plate material was coated with a 3W continuous wave YAG laser annealing device.
Annealing was performed in an Ar atmosphere by running a laser beam with a diameter of 1 mm at a speed of 1 (mm/sec.). When the heated part was observed under a microscope, it was confirmed that it had transformed into a phase different from the γ phase in a width of approximately 1.1 mm over the entire length in the thickness direction, and the transformed part was cut out and magnetized. When the amount was measured, σs = 109 (emu/
gm).

(Fe _87.8 Mn ₁₀ C _2.2 ) _98.3 Hf _1.7 to which more than 2% of C was added was uniformly treated in an Ar atmosphere at a temperature of 1100° C. for 1 hour, and then quenched by immersing it in a 10% NaOH aqueous solution. As a result of X-ray measurement of this alloy, γ
The phase diffraction lines and other diffraction lines were measured. When this alloy was cold rolled, cracks appeared and rolling into thin sheets was impossible.

Although the above has been described based on the embodiments, it is possible to draw not only a linear magnetic pattern but also any complex magnetic pattern by moving the heating beam in any desired direction. In addition, the surface of the plate material having a thickness of 50 μm opposite to the surface to be heated was cooled.
Similarly, when annealing with a laser beam, no phase transformation occurs over the entire length in the thickness direction, and when the cut surface is observed under a microscope, the depth of the part transformed to a phase different from the γ phase (α phase) can be seen. was approximately 20 μm.

It must be said that Fe--Mn--C alloys containing _Hf have high industrial utility as alloys for composite magnetic materials because of their ease of heat treatment.

Claims (1)

[Claims] 1. An alloy for composite magnetic material, characterized in that it contains 0.1 to 2.5 weight % of H _f in a composition consisting of 2 to 20 weight % Mn, 0.4 to 2 weight % C, and the balance Fe.