A heat treatment method for Fe-Cr-based soft magnetic alloy

Abstract

The application provides a heat treatment method of Fe-Cr-based soft magnetic alloy, which comprises the following steps: placing the Fe-Cr-based soft magnetic alloy into a vacuum heat treatment furnace, heating the Fe-Cr-based soft magnetic alloy to 720 DEG C to 820 DEG C at a heating speed of 200 DEG C to 300 DEG C / h and keeping the temperature for 1 h to 10 h, furnace cooling the Fe-Cr-based soft magnetic alloy to 550 DEG C to 650 DEG C at a cooling speed of 100 DEG C to 200 DEG C / h, rapidly cooling the Fe-Cr-based soft magnetic alloy to 80 DEG C to 120 DEG C at a cooling speed of 30 DEG C to 40 DEG C / h, and then taking the Fe-Cr-based soft magnetic alloy out of the furnace and air cooling to room temperature. The heat treatment method of the Fe-Cr-based soft magnetic alloy provided by the application can improve the mechanical properties of the alloy by a large margin while improving the soft magnetic properties of the alloy, and meets the use requirements under the conditions of scale reduction and large vibration.

Description

Technical Field

[0001] This invention belongs to the field of heat treatment technology, and specifically relates to a heat treatment method for Fe-Cr based soft magnetic alloys. Background Technology

[0002] Fe-Cr based soft magnetic alloys are widely used in the manufacture of various high-precision electronic devices due to their excellent soft magnetic properties and corrosion resistance. Heat treatment is often used to improve the soft magnetic properties of Fe-Cr based soft magnetic alloys; however, while improving the soft magnetic properties, the heat treatment process also affects their room temperature plasticity, impact toughness, and other mechanical properties.

[0003] Currently, the traditional heat treatment process for Fe-Cr based soft magnetic alloys typically requires holding at above 1000℃ for 10 hours followed by furnace cooling to fully release residual stress and increase grain size, thereby reducing coercivity. However, this heat treatment process easily leads to excessively large grain size, precipitation of harmful phases, and structural inhomogeneity, resulting in problems such as low room temperature plasticity and poor impact toughness of Fe-Cr based soft magnetic alloys.

[0004] Therefore, existing heat treatment processes are not conducive to obtaining Fe-Cr-based soft magnetic alloys with good room temperature plasticity and high impact toughness, which limits their service life under scaling and high vibration conditions. Summary of the Invention

[0005] To address the aforementioned technical shortcomings of existing heat treatment processes for Fe-Cr-based soft magnetic alloys, this invention provides a heat treatment method for Fe-Cr-based soft magnetic alloys. This method improves the soft magnetic properties of Fe-Cr-based alloys while also enhancing their room temperature plasticity and impact toughness, making them suitable for use in scaled-down applications and high-vibration conditions.

[0006] The technical solution provided by this invention is as follows: In a first aspect, a heat treatment method for Fe-Cr-based soft magnetic alloys includes the following steps: The Fe-Cr based soft magnetic alloy was placed in a vacuum heat treatment furnace and heated to 720℃~820℃ at a heating rate of 200~300℃ / h and held for 1h~10h. The Fe-Cr based soft magnetic alloy was furnace cooled to 550-650℃ at a cooling rate of 100-200℃ / h. The Fe-Cr based soft magnetic alloy was rapidly cooled to 80-120℃ at a rate of 30-40℃ / h and then air-cooled to room temperature after being removed from the furnace.

[0007] In a second aspect, an Fe-Cr based soft magnetic alloy is obtained by heat treatment using the heat treatment method for Fe-Cr based soft magnetic alloys described in the first aspect.

[0008] The heat treatment method for Fe-Cr based soft magnetic alloys provided by the present invention has the following beneficial effects: This invention effectively releases residual stress and improves the soft magnetic properties of Fe-Cr based soft magnetic alloys by heating them to 720℃~820℃ at a rate of 200~300℃ / h and holding them at that temperature for 1h~10h. Simultaneously, it induces the precipitation of discontinuous second phases at the grain boundaries, limiting grain size and improving the alloy's room temperature plasticity. Furnace cooling the Fe-Cr based soft magnetic alloy to 550~650℃ at a rate of 100~200℃ / h followed by rapid cooling helps reduce the precipitation of harmful phases at the grain boundaries, increasing room temperature impact toughness and making it suitable for use in scaled-down applications and high-vibration conditions. Attached Figure Description

[0009] Figure 1 The image shows the microstructure of the alloy obtained after heat treatment in Example 2. Figure 2 Photographs of the room temperature tensile fracture surface of the alloy obtained after heat treatment process in Example 2; Figure 3 Photographs of the room temperature impact fracture surface of the alloy obtained after heat treatment process in Example 2; Figure 4 The hysteresis loop of the alloy obtained after heat treatment process in Example 2. Detailed Implementation

[0010] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0011] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0012] This invention provides a heat treatment method for Fe-Cr based soft magnetic alloys, comprising the following steps: Fe-Cr based soft magnetic alloys were placed in a vacuum heat treatment furnace, with the vacuum level set to 10. -2 ~ 10 -4 Pa; The Fe-Cr based soft magnetic alloy is heated to 720℃~820℃ at a heating rate of 200~300℃ / h and held for 1h~10h, preferably heated to 770℃~820℃ at a heating rate of 200~300℃ / h and held for 5h~10h. The Fe-Cr based soft magnetic alloy is furnace cooled to 550-650℃ at a cooling rate of 100-200℃ / h, preferably to 550-630℃ at a cooling rate of 100-150℃ / h. The Fe-Cr based soft magnetic alloy is rapidly cooled to 80-120°C at 30-40°C / h and then air-cooled to room temperature. Preferably, it is rapidly cooled to 90-110°C at 30-40°C / h and then air-cooled to room temperature.

[0013] The Fe-Cr based soft magnetic alloy of this invention comprises the following components by mass percentage: C: ≤0.02%, S: ≤0.02%, P: ≤0.02%, Si: ≤0.2%, Mn: ≤0.6%, Cr: 9~17%, Mo: ≤3%, Co: ≤11%, Al: ≤1.5%, Fe: balance.

[0014] This invention effectively releases residual stress and improves the soft magnetic properties of Fe-Cr based soft magnetic alloys by heating them to 720℃~820℃ at a rate of 200~300℃ / h and holding them at that temperature for 1h~10h. Simultaneously, it induces the precipitation of discontinuous second phases at the grain boundaries, limiting grain size and improving the alloy's room temperature plasticity. Furnace cooling the Fe-Cr based soft magnetic alloy to 550~650℃ at a rate of 100~200℃ / h followed by rapid cooling helps reduce the precipitation of harmful phases at the grain boundaries, increasing room temperature impact toughness and making it suitable for use in scaled-down applications and high-vibration conditions.

[0015] The present invention also provides an Fe-Cr based soft magnetic alloy, which is obtained by heat treatment using the above-described heat treatment method for Fe-Cr based soft magnetic alloys.

[0016] Example The Fe-Cr based soft magnetic alloys used in the following examples and comparative examples are: C: 0.02%, S: 0.01%, P: 0.01%, Si: 0.2%, Mn: 0.4%, Cr: 15.6%, Mo: 2.8%, Co: 3%, Al: 0.5%, Fe: balance.

[0017] Example 1 The Fe-Cr based soft magnetic alloy was heat-treated according to the following process.

[0018] The alloy was placed in a vacuum heat treatment furnace, and the vacuum level was set to 10. -2 Pa; The alloy was heated to 770℃ at a rate of 300℃ / h and held for 5h; The alloy was furnace cooled to 550℃ at a rate of 120℃ / h; The alloy was rapidly cooled to 100℃ at a cooling rate of 30℃ / s and then air-cooled to room temperature to obtain the heat-treated Fe-Cr based soft magnetic alloy.

[0019] Example 2 The Fe-Cr based soft magnetic alloy was heat-treated according to the following process.

[0020] The alloy was placed in a vacuum heat treatment furnace, and the vacuum level was set to 10. -2 Pa; The alloy was heated to 790℃ at a rate of 300℃ / h and held for 5h; The alloy was furnace cooled to 550℃ at a rate of 120℃ / h; The alloy was rapidly cooled to 100℃ at a cooling rate of 30℃ / s and then air-cooled to room temperature to obtain the heat-treated Fe-Cr based soft magnetic alloy.

[0021] See the microstructure photograph of the alloy after heat treatment in Example 2. Figure 1 Photographs of the room temperature tensile fracture surface of the alloy after heat treatment are shown below. Figure 2 Photographs of the room temperature impact fracture surface of the alloy after heat treatment are shown below. Figure 3 The hysteresis loop of the alloy after heat treatment is shown in [reference needed]. Figure 4 .

[0022] Example 3 The Fe-Cr based soft magnetic alloy was heat-treated according to the following process.

[0023] The alloy was placed in a vacuum heat treatment furnace, and the vacuum level was set to 10. -2 Pa; The alloy was heated to 810℃ at a rate of 300℃ / h and held for 5h; The alloy was furnace cooled to 550℃ at a rate of 120℃ / h; The alloy was rapidly cooled to 100℃ at a cooling rate of 30℃ / s and then air-cooled to room temperature to obtain the heat-treated Fe-Cr based soft magnetic alloy.

[0024] Example 4 The Fe-Cr based soft magnetic alloy was heat-treated according to the following process.

[0025] The alloy was placed in a vacuum heat treatment furnace, and the vacuum level was set to 10. -2 Pa; The alloy was heated to 790℃ at a rate of 300℃ / h and held for 5h; The alloy was furnace cooled to 550℃ at a rate of 100℃ / h; The alloy was rapidly cooled to 100℃ at a cooling rate of 30℃ / s and then air-cooled to room temperature to obtain the heat-treated Fe-Cr based soft magnetic alloy.

[0026] Example 5 The Fe-Cr based soft magnetic alloy was heat-treated according to the following process.

[0027] The alloy was placed in a vacuum heat treatment furnace, and the vacuum level was set to 10. -2 Pa; The alloy was heated to 790℃ at a rate of 300℃ / h and held for 5h; The alloy was furnace cooled to 580℃ at a rate of 120℃ / h; The alloy was rapidly cooled to 100℃ at a cooling rate of 30℃ / s and then air-cooled to room temperature to obtain the heat-treated Fe-Cr based soft magnetic alloy.

[0028] Example 6 The Fe-Cr based soft magnetic alloy was heat-treated according to the following process.

[0029] The alloy was placed in a vacuum heat treatment furnace, and the vacuum level was set to 10. -2 Pa; The alloy was heated to 790℃ at a rate of 300℃ / h and held for 5h; The alloy was furnace cooled to 610℃ at a rate of 120℃ / h; The alloy was rapidly cooled to 100℃ at a cooling rate of 30℃ / s and then air-cooled to room temperature to obtain the heat-treated Fe-Cr based soft magnetic alloy.

[0030] Comparative Example 1 The heat treatment process of Comparative Example 1 is the same as that of Example 2, except that the heat treatment temperature is different; a high-temperature heat treatment of 1150℃ is used. The Fe-Cr based soft magnetic alloy is heat-treated according to the following process.

[0031] The alloy was placed in a vacuum heat treatment furnace, and the vacuum level was set to 10. -2 Pa; The alloy was heated to 1150℃ at a rate of 300℃ / h and held for 5h; The alloy was furnace cooled to 550℃ at a rate of 120℃ / h; The alloy was rapidly cooled to 100℃ at a cooling rate of 30℃ / s and then air-cooled to room temperature to obtain the heat-treated Fe-Cr based soft magnetic alloy.

[0032] Comparative Example 2 The heat treatment process of Comparative Example 2 is the same as that of Example 2, except that a stepped cooling method is not used. The Fe-Cr based soft magnetic alloy is heat treated according to the following process.

[0033] The alloy was placed in a vacuum heat treatment furnace, and the vacuum level was set to 10. -2 Pa; The alloy was heated to 790℃ at a rate of 300℃ / h and held for 5h; The alloy was cooled to room temperature in the furnace to obtain the heat-treated Fe-Cr based soft magnetic alloy.

[0034] The magnetic and mechanical properties of the above embodiments and comparative examples were tested using a universal mechanical testing machine and a soft magnetic DC measuring instrument. The test results are shown in Tables 1 and 2. Table 1 Comparison of magnetic properties of Fe-Cr based soft magnetic alloys with different heat treatment processes

[0035] Table 2 Comparison of mechanical properties of Fe-Cr based soft magnetic alloys with different heat treatment processes

[0036] As can be seen from Tables 1 and 2, the Fe-Cr based soft magnetic alloy treated by the heat treatment process of the present invention significantly improves its room temperature plasticity and impact toughness while maintaining good magnetic properties.

[0037] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0038] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A heat treatment method for Fe-Cr based soft magnetic alloys, characterized in that, Includes the following steps: The Fe-Cr based soft magnetic alloy was placed in a vacuum heat treatment furnace and heated to 720℃~820℃ at a heating rate of 200~300℃ / h and held for 1h~10h. The Fe-Cr based soft magnetic alloy was furnace cooled to 550-650℃ at a cooling rate of 100-200℃ / h. The Fe-Cr based soft magnetic alloy was rapidly cooled to 80-120℃ at a rate of 30-40℃ / h and then air-cooled to room temperature after being removed from the furnace.

2. The heat treatment method for Fe-Cr based soft magnetic alloys according to claim 1, characterized in that, In the step of placing the Fe-Cr based soft magnetic alloy into a vacuum heat treatment furnace, the vacuum degree is set to 10. -2 ~ 10 -4 Pa.

3. The heat treatment method for Fe-Cr based soft magnetic alloys according to claim 1, characterized in that, In the step of heating the Fe-Cr based soft magnetic alloy to 720℃~820℃ at a heating rate of 200~300℃ / h and holding it at that temperature for 1h~10h, it is selected to heat it to 770℃~820℃ at a heating rate of 200~300℃ / h and hold it at that temperature for 5h~10h.

4. The heat treatment method for Fe-Cr based soft magnetic alloys according to claim 1, characterized in that, In the step of furnace cooling the Fe-Cr based soft magnetic alloy to 550-650℃ at a cooling rate of 100-200℃ / h, the furnace cooling rate is selected to be 100-150℃ / h to 550-630℃.

5. The heat treatment method for Fe-Cr based soft magnetic alloys according to claim 1, characterized in that, In the step of rapidly cooling the Fe-Cr based soft magnetic alloy to 80-120°C at 30-40°C / h and then air-cooling it to room temperature, it is selected to rapidly cool it to 90-110°C at 30-40°C / h and then air-cool it to room temperature.

6. The heat treatment method for Fe-Cr based soft magnetic alloys according to claim 1, characterized in that, The Fe-Cr based soft magnetic alloy comprises the following components by mass percentage: C: ≤0.02%, S: ≤0.02%, P: ≤0.02%, Si: ≤0.2%, Mn: ≤0.6%, Cr: 9~17%, Mo: ≤3%, Co: ≤11%, Al: ≤1.5%, Fe: balance.

7. A Fe-Cr based soft magnetic alloy, characterized in that, It is obtained by heat treatment of Fe-Cr based soft magnetic alloy according to any one of claims 1 to 6.

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