JPH0236665B2 - - 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. Martensitic transformation (γ phase → martensitic phase (hereinafter referred to as α phase)) due to processing. This is a material that rarely causes Also. When the above alloy is subjected to cold working in the γ phase state, it is significantly work hardened and its mechanical strength increases. However, when an attempt is made to form the α phase, which is a ferromagnetic phase, in the γ phase matrix by heat treatment, the γ phase is stable at low temperatures, so the γ→α transformation does not easily occur during the heat treatment, and the γ→α A long heat treatment is required to complete the transformation. 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 has α+γ+ between the α and γ phases.
A mixed phase of Fe ₃ C or γ+Fe ₃ C is formed, and Fe ₃ C is strongly bonded.

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

The present invention provides an alloy for composite magnetic materials characterized in that Ah is added to the above alloy in order to easily transform the γ phase of the above alloy introduced into room temperature into the α phase by subjecting it to a short heat treatment. The present invention aims to provide an alloy for composite magnetic materials that is industrially effective, has a wide range of applications, and is excellent in productivity by taking advantage of the advantages of the alloy and solving the drawbacks.

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., magnetic properties can be formed on the surface of a non-magnetic material at an arbitrary depth and in an arbitrary pattern. It became possible to form a 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 produced by the method of the present invention has a mechanical It was also found to be superior in terms of reliability.

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 contains up to about 2% by weight of C as a solid solution,
It forms a γ-region and becomes stable, but in order to rapidly cool from a high temperature and introduce the γ phase to room temperature, it is necessary to add 2% by weight or more.
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, Al, 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 4.0% by weight of Al was added to facilitate the γ→α transformation.
When the amount added is less than 0.1% by weight, the effect of Al addition is not exhibited, and when it is added more than 4.0% by weight, it becomes an 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 the composition (Fe _85.8 Mn ₁₃ C _1.2 ) 98 Al _2.0 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 is cut out from this alloy ingot and the amount of magnetization is measured, σ _s =
It was a γ phase of 0.02 (emu/gm). After removing the surface oxide film of this alloy ingot, the area reduction rate is 50%.
When subjected to cold rolling processing, the amount of magnetization is σ _s =
It became 0.05 (emu/gm). Furthermore, when this alloy ingot was further cold-rolled with an area reduction of 99% from its initial shape, the amount of magnetization was σ _s = 0.1.
It became (emu/gm). Also, mechanical strength σ _0.2 = 150
Kg/mm ² and Bitkers hardness Hv=750.

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. As a result, magnetization amount σ _s = 135 (emu/gm), mechanical strength σ _0.2 = 95
(Kg/gm ² ), and became an α phase with a Bitkers hardness of Hv=523.

In addition, the surface of the γ phase plate material with a thickness of 50 μm was
Annealing was performed in an Ar atmosphere using a 3W continuous wave YAG laser annealing device with a laser beam of 1 mm diameter traveling 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=125 (emu/gm).

Example 2 An alloy ingot having the composition (Fe ₉₆ Mn ₂ C _2.0 ) 96 Al _4.0 in weight percent was heated at a temperature of 1100° C. for 1 hour.
After homogenization treatment in an Ar atmosphere, it was immersed in a 10% NsOH aqueous solution and rapidly cooled. When a small piece is cut out from this alloy ingot and the amount of magnetization is measured, σ _s = 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 σ _s = 0.3
It became (emu/gm). Also, mechanical strength σ _0.2 = 140
Kg/mm ² and Bitkers hardness Hv=650.

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. As a result, magnetization amount σ _s = 153 (emu/gm), mechanical strength σ _0.2 = 87
(Kg/mm ² ), and the Bitkers hardness was Hv=505.

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, σ _s = 140 (emu/
gm).

Example 3 An alloy ingot having a chemical composition of (Fe _79.6 Mn ₂₀ C _0.4 ) 99.9 Al _0.1 in weight % was heated at a temperature of 1100°C.
time, 10% NsOH after homogenization treatment in Ar atmosphere
It was quenched by immersing it in an aqueous solution. When a small piece is cut out from this alloy ingot and the amount of magnetization is measured, σ _s =
It was a γ phase of 0.03 (emu/gm). After removing the surface oxide film of this alloy ingot, the area reduction rate is 99%.
When subjected to cold rolling processing, the amount of magnetization σ _s = 0.2
It became (emu/gm). Also, mechanical strength σ _0.2 = 125
(Kg/mm ² ) and Bitkers hardness Hv=590.

The 50 μm thick γ phase plate material cold rolled as described above was rapidly cooled at 500° C. for 5 seconds in an Ar atmosphere. As a result, the magnetization amount σ _s = 1181 (emu/
gm), mechanical strength σ _0.2 = 81 (Kg/mm ² ), and Vickers hardness Hv = 495.

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 and magnetized. When the amount was measured, σ _s = 109 (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 σ _s =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 material was heat-treated at a temperature of 950° C. for 5 seconds in an Ar atmosphere, and then rapidly cooled in an Ar atmosphere. As a result, the magnetization amount σ _s =0.02 (emu/gm), the mechanical strength σ _0.2 =58 (Kg/mm ² ), and the Vickers hardness Hv = 280.

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 σ _s =
121 (emu/gm), mechanical strength σ _0.2 = 75 (Kg/mm ² ),
It became an α phase with a Bitkers hardness of Hv=420. Also,
The surface of the 50 μm thick γ-phase plate material was annealed in an Ar atmosphere using a 3W continuous wave YAG laser annealing device with a 1 mm diameter laser beam traveling 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. was measured, α of σ _s = 111 (emu/gm)
It was a phase.

Example 5 The composition alloy ingot used in Example 1 was heated to 1100°C.
After homogenizing in an Ar atmosphere for 1 hour at a temperature of 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 σ _s =0.02 (emu/gm). After removing the surface oxide film of this alloy ingot, it was cold-rolled with an area reduction rate of 75% and then rolled again.
After homogenization treatment at a temperature of 950° C. for 30 minutes in an Ar atmosphere, it was immersed in the above solution and rapidly cooled. As a result, the magnetization amount is σ _s = 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 σ _s = 0.05 (emu/gm), mechanical strength σ _0.2 = 130 (Kg/mm ² ), and Vickers hardness Hv = 680.
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 σ _s = 131
(emu/gm), mechanical strength σ _0.2 = 91 (Kg/mm ² ), and Vickers hardness Hv = 518.

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 was 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.The transformed part was cut out and the magnetization amount was determined. When we measured σ _s = 120 (emu/
gm).

(Fe _87.8 Mn ₁₀ C _2.2 ) _98.0 An alloy containing more than 2% of Al _2.0 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, when the heated surface of a 50 μm thick plate material is cooled and annealed with a laser beam in the same manner as in Example 1, no phase transformation occurs over the entire length in the thickness direction, and when the cut surface is observed under a microscope, it appears as γ phase. The depth of the part where the phase was transformed into a different phase (α phase) was about 20 μm.

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

Claims (1)

[Claims] 1. An alloy for a composite magnetic material, characterized in that the composition consists of Mn: 2 to 20% by weight, C: 0.4 to 2% by weight, and the balance Fe, containing 0.1 to 4% by weight of Al.