Iron-nickel soft magnetic alloy with high magnetic conductivity and high magnetic induction and preparation method thereof

Abstract

The invention relates to an iron-nickel magnetically soft alloy, in particular to an iron-nickel magnetically soft alloy with high magnetic conductivity and high magnetic induction and a preparation method of the iron-nickel magnetically soft alloy. The iron-nickel magnetically soft alloy comprises the following chemical components in percentage by mass: 48.00 to 51.00 percent of N , 0.10 to 0.30 percent of Mn, 2.50 to 5.00 percent of Cr, 1.00 to 1.50 percent of T , 0 to 0.30 percent of A < l >, less than 0.10 percent of S , less than 0.02 percent of C and the balance of Fe and inevitable impurities. The preparation method is realized based on the chemical components. On the basis of an existing 1J50 alloy, 2.50-5.00% of Cr, 1.00-1.50% of Ti and 0-0.30% of A are added, and the mechanical property, corrosion resistance and conductivity of the iron-nickel magnetically soft alloy can be improved on the premise that the magnetic property of the iron-nickel magnetically soft alloy is not affected.

Description

Technical Field

[0001] The invention relates to an iron-nickel soft magnetic alloy, in particular to an iron-nickel soft magnetic alloy with high magnetic permeability and high magnetic induction and a preparation method thereof. Background Art

[0002] 1J50 alloy is one of the most excellent permalloy materials currently available. It is a soft magnetic alloy with medium saturation induction and medium permeability, belonging to the precision alloy family. Its primary chemical components are Fe and Ni, with impurities such as C, P, S, Si, and Mn. 1J50 alloy exhibits low thermal expansion and a nearly constant coefficient of thermal expansion within its operating temperature range, while maintaining high dimensional stability. Therefore, 1J50 alloy is widely used in the manufacture of micromotors, low-power transformers, relays, and other high-precision instruments, particularly in inertial navigation systems.

[0003] However, the existing 1J50 alloy cannot ensure high magnetic properties while also having good mechanical properties; resulting in reduced reliability and shortened service life of components made of 1J50 alloy. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problem that the current medium-iron-nickel soft magnetic alloy cannot maintain high magnetic properties while having good mechanical properties, and to provide a high magnetic permeability, high magnetic induction iron-nickel soft magnetic alloy and a preparation method thereof.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] A high permeability, high magnetic induction iron-nickel soft magnetic alloy, whose chemical composition is as follows in mass percentage:

[0007] Ni: 48.00-51.00%, Mn: 0.10-0.30%, Cr: 2.50-5.00%, Ti: 1.00-1.50%, Al: 0-0.30%, Si<0.10%, C<0.02%, and the balance is Fe and inevitable impurities.

[0008] A method for preparing a high-permeability, high-magnetic-induction iron-nickel soft magnetic alloy comprises the following steps:

[0009] 1) Weighing pure iron, nickel plate, metallic manganese, metallic chromium, titanium plate, aluminum ingot, metallic silicon and carbon as raw materials according to their chemical compositions;

[0010] 2) placing the raw materials in a vacuum induction furnace, and obtaining a molten alloy after preheating, melting, refining and alloying in the vacuum induction furnace;

[0011] 3) Filling the pouring chamber of the vacuum induction furnace with argon gas and pouring the alloy liquid under the argon atmosphere;

[0012] After the pouring is completed, the vacuum is broken and a heating agent is added into the riser to cover the alloy liquid, and the alloy ingot is obtained after cooling and demoulding;

[0013] 4) The alloy ingot is subjected to three-stage forging, and after cooling, a forging blank with a specification of φ40±5mm×L is obtained;

[0014] 5) The forging blank is heat treated in a vacuum or dry hydrogen environment, and after cooling, a high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy is obtained.

[0015] Furthermore, step 2) is specifically as follows:

[0016] Pure iron, nickel plate and carbon are placed into the crucible of the vacuum induction furnace. Meanwhile, metal manganese, metal chromium, titanium plate, aluminum ingot, metal silicon and carbon are placed into the small hopper of the vacuum induction furnace respectively.

[0017] After the loading is completed, the furnace is closed and the vacuum induction furnace is evacuated to ≤10Pa, and the smelting stage begins;

[0018] Preheat the crucible of the vacuum induction furnace at a power of 150-200kw for 70-90min. At the same time, evacuate the vacuum induction furnace to ≤3Pa;

[0019] Increase the power to 300-400kw to melt the pure iron, nickel plate and carbon in the crucible for 10-14 hours;

[0020] After smelting is completed, it enters the refining stage;

[0021] Detect the carbon content in the molten steel in the crucible and calculate the mass of carbon that needs to be added;

[0022] Heat the crucible to 1560℃~1590℃. At the same time, add additional carbon into the crucible in equal portions, adding each portion to the crucible at intervals of 5~8 minutes. After the additional carbon is completely melted, refine for 70~100 minutes.

[0023] After refining, argon is filled into the vacuum induction furnace to a pressure of 5000 Pa to enter the alloying stage;

[0024] Add metallic silicon and metallic chromium into the crucible and stir thoroughly until they melt;

[0025] 10 to 12 minutes before the end of the alloying stage, add metallic manganese and aluminum ingots into the crucible and stir them thoroughly until they melt to obtain an alloy liquid that meets the chemical composition.

[0026] Furthermore, in step 2), the pure iron, nickel plate and furnace carbon are divided into multiple portions, and the multiple portions of pure iron, nickel plate and furnace carbon are alternately loaded into the crucible of the vacuum induction furnace in sequence.

[0027] Furthermore, in step 3), the specific method of pouring the alloy liquid under argon atmosphere is:

[0028] Casting under the temperature of 1500℃~1530℃;

[0029] Pouring is carried out below the riser line of the alloy ingot mold at a pouring speed of 0.2-1kg / s;

[0030] When the alloy liquid in the alloy ingot mold reaches the riser line, pouring is carried out at a speed of 0.02-0.1kg / s.

[0031] Furthermore, step 4) is specifically as follows:

[0032] Use a gas furnace to heat the alloy ingot with a temperature below 200°C to 800-900°C and keep it warm for 6-9 hours;

[0033] After the insulation is completed, the alloy ingot is heated to 1150-1180℃ and subjected to a second insulation, the second insulation time being 5-8h;

[0034] After the secondary heat preservation is completed, the alloy ingot is forged into an initial forging blank with a specification of (200-230 mm)×(200-230 mm)×L, where L is the length of the forging blank and the forging ratio is ≥9;

[0035] If the temperature of the initial forging billet is lower than 950℃ during the forging process, it should be returned to the furnace for heating and re-forging.

[0036] Grinding the initial forging blank;

[0037] Use a gas furnace to heat the initial forging billet with a temperature below 200°C to 800-900°C and keep it at this temperature for 2-3 hours;

[0038] After the insulation is completed, the initial forging billet is heated to 1120-1140℃ and subjected to secondary insulation for 1-2 hours;

[0039] After the secondary heat preservation is completed, the initial forging billet is forged into an intermediate forging billet with a specification of φ80-100mm×L, and the forging ratio is ≥5;

[0040] If the temperature of the intermediate forging billet is lower than 950℃ during the forging process, it should be returned to the furnace for heating and re-forging.

[0041] Grind the intermediate forging blank;

[0042] Use a gas furnace to heat the intermediate forging billet with a temperature below 200°C to 800-900°C and keep it warm for 1-2 hours;

[0043] After the insulation is completed, the intermediate forging billet is heated to 1140-1160℃ and subjected to secondary insulation for 0.5-1.5h.

[0044] After the secondary heat preservation is completed, the intermediate forging billet is forged into a forging billet with a specification of (φ35-45mm)×L, with a forging ratio of ≥4; the final forging temperature is lower than 950°C.

[0045] Furthermore, when the initial forging blank is cooled, if the temperature of the initial forging blank is higher than 800° C., sand cooling is performed, otherwise, air cooling is performed;

[0046] When the intermediate forging billet is cooled, if the temperature of the intermediate forging billet is higher than 800℃, sand cooling is performed, otherwise, air cooling is performed;

[0047] When the forging blank is cooled, if the temperature of the forging blank is higher than 800℃, sand cooling is performed, otherwise, water cooling is performed.

[0048] Furthermore, in step 5), the specific method of heat treatment is:

[0049] Place the forging blank in a vacuum heat treatment furnace or a hydrogen atmosphere heat treatment furnace and perform heat treatment on the forging blank in a vacuum or dry hydrogen environment:

[0050] Heat the forging billet to 1100-1250℃, 1000℃, and 700-800℃ in sequence, and keep them warm for 5-10h, 1-2h, and 0.5-2h respectively;

[0051] After the insulation is completed, the forging billet is cooled to 500℃ with the furnace, quickly cooled to 150℃, and finally cooled to room temperature with the furnace to complete the heat treatment of the forging billet.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] 1. The high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy provided by the present invention, on the basis of the existing 1J50 alloy, adds 2.50-5.00% Cr, which can improve the corrosion resistance of the iron-nickel soft magnetic alloy; adds 1.00-1.50% Ti, which can improve the mechanical properties of the iron-nickel soft magnetic alloy; by adding 0-0.30% Al, the resistivity of the iron-nickel soft magnetic alloy can be improved; since the addition amounts of Cr, Ti and Al are relatively small, they will not affect the magnetic properties of the iron-nickel soft magnetic alloy, which helps to achieve good mechanical properties, corrosion resistance and electrical conductivity while maintaining high magnetic properties.

[0054] 2. The preparation method of the high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy provided by the present invention adopts three-fire forging. During the first fire forging, the alloy ingot is heated at a temperature of 1150-1180°C, which can improve the fluidity of the alloy and enable the alloy ingot to produce a large deformation during the forging process, which is beneficial to destroying the coarse grains and segregation in the cast structure in the alloy ingot. After the initial forging is completed, the initial forging blank is slowly cooled in stages, that is, the temperature is higher than 800°C, sand cooling is performed, and the temperature is lower than 800°C, air cooling is performed, so that the initial forging blank can effectively undergo static recrystallization and form a uniform two-phase structure, creating favorable organizational conditions for the second fire forging; during the second fire forging, the initial forging blank is heated at a temperature of 1120-1140°C , which is conducive to further refining the grains of the initial forging billet and promoting dynamic recrystallization. After the intermediate forging is completed, it is slowly cooled in stages, that is, when the temperature is above 800℃, it is sand-cooled, and when the temperature is below 800℃, it is air-cooled. This can effectively make the intermediate forging billet undergo static recrystallization and form a uniform equiaxed structure. During the third forging, the intermediate forging billet is heated at 1140-1160℃ to eliminate the residual stress generated by the second forging, and to re-dissolve the hard secondary phases such as (Fe, Ni)3 generated by the slow cooling of the second forging, further optimize the uniformity of the structure, and make the forging billet have greater fluidity, so as to facilitate the acquisition of the target size of the forging billet. Water cooling after forging helps to quickly cool the alloy and quickly pass through the eutectoid point and disordered transformation into an ordered phase region. Through multi-fire forging, the uniformity of the structure of the iron-nickel soft magnetic alloy is significantly improved, and the presence of segregation and coarse grains is reduced. DETAILED DESCRIPTION

[0055] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0056] A high permeability, high magnetic induction iron-nickel soft magnetic alloy, whose chemical composition is as follows in mass percentage:

[0057] Ni: 48.00-51.00%, Mn: 0.10-0.30%, Cr: 2.50-5.00%, Ti: 1.00-1.50%, Al: 0-0.30%, Si<0.10%, C<0.02%, and the balance is Fe and inevitable impurities.

[0058] Ni: helps to improve the initial magnetic permeability (μ0) and maximum magnetic permeability (μm) of the iron-nickel soft magnetic alloy and reduce the coercive force (Hc). Too low nickel content can easily lead to an increase in the coercive force (Hc) and a decrease in the initial magnetic permeability (μ0) and maximum magnetic permeability (μm). Too high nickel content can easily lead to a decrease in the saturation magnetic induction intensity (Bs). In order to make the iron-nickel soft magnetic alloy have high initial magnetic permeability (μ0), maximum magnetic permeability (μm) and saturation magnetic induction intensity (Bs), and reduce the coercive force (Hc), the nickel content is preferably (mass percentage) 48.00-51.00%.

[0059] Mn: used to adjust the magnetocrystalline anisotropy constant and magnetostriction coefficient of the iron-nickel soft magnetic alloy, so that the magnetocrystalline anisotropy constant and magnetostriction coefficient of the iron-nickel soft magnetic alloy approach zero, which helps to reduce the coercive force (Hc) of the iron-nickel soft magnetic alloy.

[0060] Cr: The higher the chromium content, the better the corrosion resistance of the alloy, but the lower the saturation magnetic flux density (Bs). The practical range of chromium content is limited to about 2.5% to 5%, because excessive chromium will lead to insufficient saturation magnetic flux density (Bs).

[0061] Ti: Adding titanium can improve the mechanical properties of iron-nickel soft magnetic alloys.

[0062] Al: Used to increase the resistivity of iron-nickel soft magnetic alloys. Resistivity is also very important for soft magnetic materials. It can reduce eddy currents and improve frequency response.

[0063] C: Carbon is an element that forms interstitial solid solutions. Interstitial atoms will cause domain wall displacement resistance and have an adverse effect on the magnetic properties of the alloy. However, it can improve the hardness of the alloy to a certain extent. Therefore, the carbon content is preferably (mass percentage) <0.02%.

[0064] Inevitable impurities are impurities introduced by the raw materials nickel, manganese, silicon, chromium, aluminum, titanium, carbon and iron themselves; the total amount of inevitable impurities is less than 0.10%.

[0065] A method for preparing a high-permeability, high-magnetic-induction iron-nickel soft magnetic alloy comprises the following steps:

[0066] 1) Weighing pure iron, nickel plate, metallic manganese, metallic chromium, titanium plate, aluminum ingot, metallic silicon and carbon as raw materials according to their chemical compositions;

[0067] 2) Divide the pure iron, nickel plate and furnace carbon into multiple portions, and alternately load the portions of pure iron, nickel plate and furnace carbon into the crucible of the vacuum induction furnace; at the same time, load metal manganese, metal chromium, titanium plate, aluminum ingot, metal silicon and carbon into the small hopper of the vacuum induction furnace respectively;

[0068] After the loading is completed, the furnace is closed and the vacuum induction furnace is evacuated to ≤10Pa, and the smelting stage begins;

[0069] Preheat the crucible of the vacuum induction furnace at a power of 150-200kw for 70-90min. At the same time, evacuate the vacuum induction furnace to ≤3Pa;

[0070] Increase the power to 300-400kw to melt the pure iron, nickel plate and carbon in the crucible for 10-14 hours;

[0071] After smelting is completed, it enters the refining stage;

[0072] Detect the carbon content in the molten steel in the crucible and calculate the mass of carbon that needs to be added;

[0073] Heat the crucible to 1560℃~1590℃. At the same time, add additional carbon into the crucible in equal portions, adding each portion to the crucible at intervals of 5~8 minutes. After the additional carbon is completely melted, refine for 70~100 minutes.

[0074] After refining, argon is filled into the vacuum induction furnace to a pressure of 5000 Pa to enter the alloying stage;

[0075] Add metallic silicon and metallic chromium into the crucible and stir thoroughly until they melt;

[0076] 10-12 minutes before the end of the alloying stage, add the manganese metal and aluminum ingots into the crucible and stir them thoroughly until they melt to obtain an alloy liquid that meets the chemical composition.

[0077] 3) Fill the pouring chamber of the vacuum induction furnace with argon gas and pour the alloy liquid under the argon atmosphere; the specific method of pouring the alloy liquid under the argon atmosphere is as follows:

[0078] Casting under the temperature of 1500℃~1530℃;

[0079] Pouring is carried out below the riser line of the alloy ingot mold at a pouring speed of 0.2-1kg / s;

[0080] When the alloy liquid in the alloy ingot mold reaches the riser line, pouring is carried out at a speed of 0.02-0.1kg / s;

[0081] After the pouring is completed, the vacuum is broken and a heating agent is added into the riser to cover the alloy liquid, and the alloy ingot is obtained after cooling and demoulding;

[0082] 4) The alloy ingot is subjected to three-stage forging, and after cooling, a forging blank with a specification of φ40±5mm×L is obtained;

[0083] Use a gas furnace to heat the alloy ingot with a temperature below 200°C to 800-900°C and keep it warm for 6-9 hours;

[0084] After the insulation is completed, the alloy ingot is heated to 1150-1180℃ and subjected to a second insulation, the second insulation time being 5-8h;

[0085] After the secondary heat preservation is completed, the alloy ingot is forged into an initial forging blank with a specification of (200-230 mm)×(200-230 mm)×L, where L is the length of the forging blank and the forging ratio is ≥9;

[0086] If the temperature of the initial forging billet is lower than 950℃ during the forging process, it should be returned to the furnace for heating and re-forging.

[0087] When the initial forging billet is cooled, if the temperature of the initial forging billet is higher than 800℃, sand cooling is performed, otherwise, air cooling is performed;

[0088] Grinding the initial forging blank;

[0089] Use a gas furnace to heat the initial forging billet with a temperature below 200°C to 800-900°C and keep it at this temperature for 2-3 hours;

[0090] After the insulation is completed, the initial forging billet is heated to 1120-1140℃ and subjected to secondary insulation for 1-2 hours;

[0091] After the secondary heat preservation is completed, the initial forging billet is forged into an intermediate forging billet with a specification of φ80-100mm×L, and the forging ratio is ≥5;

[0092] If the temperature of the intermediate forging billet is lower than 950℃ during the forging process, it should be returned to the furnace for heating and re-forging.

[0093] When the intermediate forging billet is cooled, if the temperature of the intermediate forging billet is higher than 800℃, sand cooling is performed, otherwise, air cooling is performed;

[0094] Grind the intermediate forging blank;

[0095] Use a gas furnace to heat the intermediate forging billet with a temperature below 200°C to 800-900°C and keep it warm for 1-2 hours;

[0096] After the insulation is completed, the intermediate forging billet is heated to 1140-1160℃ and subjected to secondary insulation for 0.5-1.5h.

[0097] After the secondary heat preservation is completed, the intermediate forging billet is forged into a forging billet with a specification of (φ35-45mm)×L, with a forging ratio of ≥4; the final forging temperature is lower than 950°C.

[0098] When the forging blank is cooled, if the temperature of the forging blank is higher than 800℃, sand cooling is performed, otherwise, water cooling is performed;

[0099] 5) Heat treatment of the forging blank is performed in a vacuum or dry hydrogen environment. The specific method of heat treatment is as follows:

[0100] Place the forging blank in a vacuum heat treatment furnace or a hydrogen atmosphere heat treatment furnace and perform heat treatment on the forging blank in a vacuum or dry hydrogen environment:

[0101] Heat the forging billet to 1100-1250℃, 1000℃, and 700-800℃ in sequence, and keep them warm for 5-10h, 1-2h, and 0.5-2h respectively;

[0102] After the insulation is completed, the forging billet is cooled to 500°C with the furnace, quickly cooled to 150°C, and finally cooled to room temperature with the furnace to complete the heat treatment of the forging billet; and a high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy is obtained.

[0103] Specific examples are given below.

[0104] Example 1

[0105] 1) Weighing pure iron, nickel plate, metallic manganese, metallic chromium, titanium plate, aluminum ingot, metallic silicon and carbon as raw materials according to their chemical compositions;

[0106] Its chemical composition, in mass percentage, is: Ni: 50.5%, Mn: 0.25%, Cr: 5.31%, Ti: 1.21%, Al: 0.26%, Si: 0.05%, C: 0.015%, and the balance is Fe and unavoidable impurities;

[0107] 2) Divide pure iron, nickel plates, and furnace carbon into five equal portions, and alternately load multiple portions of pure iron, nickel plates, and furnace carbon into the crucible of a vacuum induction furnace; simultaneously, load metallic manganese, metallic chromium, titanium plates, aluminum ingots, metallic silicon, and carbon into the small hopper of the vacuum induction furnace respectively;

[0108] After the loading is completed, the furnace is closed and the vacuum induction furnace is evacuated to 8Pa to enter the smelting stage;

[0109] The crucible of the vacuum induction furnace was preheated at a power of 180 kW for 90 min. At the same time, the vacuum induction furnace was evacuated to 3 Pa.

[0110] Increase the power to 320kw to melt the pure iron, nickel plate and carbon in the crucible for 10 hours;

[0111] After smelting is completed, it enters the refining stage;

[0112] Detect the carbon content in the molten steel in the crucible and calculate the mass of carbon that needs to be added;

[0113] Heat the crucible to 1570℃. At the same time, add the additional carbon into the crucible in three equal portions, adding each portion to the crucible at intervals of 5 to 8 minutes. After the additional carbon is completely melted, refine for 100 minutes.

[0114] After refining, argon is filled into the vacuum induction furnace to a pressure of 5000 Pa to enter the alloying stage;

[0115] Add metallic silicon and metallic chromium into the crucible and stir thoroughly until they melt;

[0116] 12 minutes before the end of the alloying stage, add the manganese metal and aluminum ingots into the crucible and stir them thoroughly until they melt to obtain an alloy liquid with the correct chemical composition.

[0117] 3) Fill the pouring chamber of the vacuum induction furnace with argon gas and pour the alloy liquid under the argon atmosphere; the specific method of pouring the alloy liquid under the argon atmosphere is as follows:

[0118] Casting under 1530℃;

[0119] Pouring is carried out below the riser line of the alloy ingot mold at a pouring speed of 1 kg / s;

[0120] When the alloy liquid in the alloy ingot mold reaches the riser line, pouring is carried out at a speed of 0.1kg / s;

[0121] After the pouring is completed, the vacuum is broken and a heating agent is added into the riser to cover the alloy liquid, and the alloy ingot is obtained after cooling and demoulding;

[0122] 4) Perform three-stage forging on the alloy ingot:

[0123] First forging: Use a gas furnace to heat the alloy ingot with a temperature below 200℃ to 900℃ and keep it warm for 8 hours;

[0124] After the insulation is completed, the alloy ingot is heated to 1180°C and subjected to a second insulation, the second insulation time being 8 hours;

[0125] After the secondary heat preservation is completed, the alloy ingot is forged into an initial forging blank with a specification of 230 mm × 230 mm × L, where L is the length of the forging blank and the forging ratio is 10;

[0126] If the temperature of the initial forging billet is lower than 950℃ during the forging process, it should be returned to the furnace for heating and re-forging.

[0127] When the initial forging billet is cooled, if the temperature of the initial forging billet is higher than 800℃, sand cooling is performed, otherwise, air cooling is performed;

[0128] Second forging: Grind the initial forging blank;

[0129] Use a gas furnace to heat the initial forging billet with a temperature below 200°C to 900°C and keep it at this temperature for 3 hours;

[0130] After the insulation is completed, the initial forging billet is heated to 1140℃ and subjected to secondary insulation for 2h.

[0131] After the secondary heat preservation is completed, the initial forging billet is forged into an intermediate forging billet with a specification of φ100mm×L, and the forging ratio is 5;

[0132] If the temperature of the intermediate forging billet is lower than 950℃ during the forging process, it should be returned to the furnace for heating and re-forging.

[0133] When the intermediate forging billet is cooled, if the temperature of the intermediate forging billet is higher than 800℃, sand cooling is performed, otherwise, air cooling is performed;

[0134] The third forging: grinding the intermediate forging blank;

[0135] Use a gas furnace to heat the intermediate forging billet with a temperature below 200°C to 900°C and keep it at this temperature for 2 hours;

[0136] After the insulation is completed, the intermediate forging billet is heated to 1160℃ and subjected to secondary insulation for 1.5 hours.

[0137] After the secondary heat preservation is completed, the intermediate forging billet is forged into a forging billet with a specification of φ35mm×L, and the forging ratio is 4; the final forging temperature of the forging is lower than 950℃.

[0138] When the forging blank is cooled, if the temperature of the forging blank is higher than 800℃, sand cooling is performed, otherwise, water cooling is performed;

[0139] 5) Heat treatment of the forging blank is performed in a dry hydrogen environment. The specific method of heat treatment is as follows:

[0140] Divide the forging blank into two parts and place them in a hydrogen atmosphere heat treatment furnace. Heat treat the forging blank in a dry hydrogen environment:

[0141] Heat one of the forging blanks to 1200℃, 1000℃, and 800℃ in sequence, and keep them at these temperatures for 8h, 2h, and 2h respectively;

[0142] Heat the other forging blank to 1200℃, 1000℃ and 800℃ in sequence, and keep them at this temperature for 8h, 2h and 1h respectively;

[0143] After the insulation is completed, the forging blank is cooled to 500°C with the furnace, quickly cooled to 150°C, and finally cooled to room temperature with the furnace to complete the heat treatment of the forging blank; and two portions of high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy are obtained.

[0144] Example 2

[0145] Compared with Example 1, Example 2 differs in that: in step 1), its chemical composition, in mass percentage, is: Ni: 48.31%, Mn: 0.23%, Cr: 3.82%, Ti: 1.54%, Al: 0.21%, Si: 0.04%, C: 0.009%, and the remainder is Fe and unavoidable impurities; in step 5), the forging billet is kept at 800°C for 1 hour.

[0146] Example 3

[0147] Compared with Example 1, Example 3 differs in that: in step 1), its chemical composition, in mass percentage, is: Ni: 49.67%, Mn: 0.20%, Cr: 3.53%, Ti: 1.40%, Al: 0.22%, Si: 0.03%, C: 0.007%, and the remainder is Fe and unavoidable impurities; in step 5), the forging billet is kept at 800°C for 0.5h.

[0148] Example 4

[0149] Compared with Example 1, Example 4 differs in that: in step 1), its chemical composition, in mass percentage, is: Ni: 48.62%, Mn: 0.19%, Cr: 4.25%, Ti: 1.45%, Al: 0.21%, Si: 0.03%, C: 0.006%, and the remainder is Fe and unavoidable impurities; in step 5), the forging billet is kept at 800°C for 0.5h.

[0150] Comparative Example

[0151] The comparative example is a 1J50 soft magnetic alloy prepared using the existing preparation process.

[0152] The chemical composition comparison table of the high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloys prepared in Examples 1-4 and the 1J50 soft magnetic alloy of the comparative example, and the specific results are shown in Table 1.

[0153] Table 1: Chemical composition comparison table

[0154] Ni Cr Ti Al Mn Si C Fe Example 1 50.50％ 5.31％ 1.21％ 0.26％ 0.25％ 0.05％ 0.015％ margin Example 2 48.31％ 3.82％ 1.54％ 0.21％ 0.23％ 0.04％ 0.009％ margin Example 3 49.67％ 3.53％ 1.40％ 0.22％ 0.20％ 0.03％ 0.007％ margin Example 4 48.62％ 3.53％ 1.40％ 0.22％ 0.20％ 0.03％ 0.007％ margin Comparative Example 50.5％ / / / 0.6％ 0.3％ 0.02％ margin

[0155] The hardness (HB), coercive force (Hc), initial magnetic permeability (μ0), maximum magnetic permeability (μm), saturation magnetic induction intensity (Bs) and resistivity of the high magnetic permeability, high magnetic induction iron-nickel soft magnetic alloys prepared in Examples 1-4 and the 1J50 alloy of the comparative example were tested; the specific test results are shown in Table 2.

[0156] Table 2: Hardness, magnetic properties and resistivity test table

[0157]

[0158] Combining Tables 1 and 2, it is clear that the addition of Cr, Ti, and Al to the existing 1J50 soft magnetic alloy effectively increases the Brinell hardness and resistivity of the iron-nickel soft magnetic alloy. By performing three-stage forging and controlling the heat treatment holding time, high magnetic properties can be maintained while also achieving good mechanical and electrical conductivity.

[0159] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention shall be covered by the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A high permeability, high magnetic induction iron-nickel soft magnetic alloy, characterized in that: In terms of mass percentage, its chemical composition is: Ni: 48.00-51.00%, Mn: 0.10-0.30%, Cr: 2.50-5.00%, Ti: 1.00-1.50%, Al: 0-0.30%, Si<0.10%, C<0.02%, and the balance is Fe and inevitable impurities.

2. A method for preparing a high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy, characterized in that: The steps include: 1) Weighing pure iron, nickel plate, metallic manganese, metallic chromium, titanium plate, aluminum ingot, metallic silicon and carbon as raw materials according to their chemical compositions; 2) placing the raw materials in a vacuum induction furnace, and obtaining a molten alloy after preheating, melting, refining and alloying in the vacuum induction furnace; 3) Filling the pouring chamber of the vacuum induction furnace with argon gas and pouring the alloy liquid under the argon atmosphere; After the pouring is completed, the vacuum is broken and a heating agent is added into the riser to cover the alloy liquid, and the alloy ingot is obtained after cooling and demoulding; 4) The alloy ingot is subjected to three-stage forging, and after cooling, a forging blank with a specification of φ40±5mm×L is obtained; 5) The forging blank is heat treated in a vacuum or dry hydrogen environment, and after cooling, a high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy is obtained.

3. The method for preparing the high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy according to claim 2, characterized in that: Step 2) is specifically as follows: Pure iron, nickel plate and carbon are placed into the crucible of the vacuum induction furnace. Meanwhile, metal manganese, metal chromium, titanium plate, aluminum ingot, metal silicon and carbon are placed into the small hopper of the vacuum induction furnace respectively. After the loading is completed, the furnace is closed and the vacuum induction furnace is evacuated to ≤10Pa, and the smelting stage begins; Preheat the crucible of the vacuum induction furnace at a power of 150-200kw for 70-90min. At the same time, evacuate the vacuum induction furnace to ≤3Pa; Increase the power to 300-400kw to melt the pure iron, nickel plate and carbon in the crucible for 10-14 hours; After smelting is completed, it enters the refining stage; Detect the carbon content in the molten steel in the crucible and calculate the mass of carbon that needs to be added; Heat the crucible to 1560℃~1590℃. At the same time, add additional carbon into the crucible in equal portions, adding each portion to the crucible at intervals of 5~8 minutes. After the additional carbon is completely melted, refine for 70~100 minutes. After refining, argon is filled into the vacuum induction furnace to a pressure of 5000 Pa to enter the alloying stage; Add metallic silicon and metallic chromium into the crucible and stir thoroughly until they melt; 10 to 12 minutes before the end of the alloying stage, add metallic manganese and aluminum ingots into the crucible and stir them thoroughly until they melt to obtain an alloy liquid that meets the chemical composition.

4. The method for preparing the high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy according to claim 3, characterized in that: In step 2), the pure iron, nickel plate and furnace carbon are divided into multiple portions, and the multiple portions of pure iron, nickel plate and furnace carbon are alternately loaded into the crucible of the vacuum induction furnace.

5. The method for preparing the high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy according to claim 2, characterized in that: In step 3), the specific method of pouring the alloy liquid under argon atmosphere is: Casting under the temperature of 1500℃~1530℃; Pouring is carried out below the riser line of the alloy ingot mold at a pouring speed of 0.2-1kg / s; When the alloy liquid in the alloy ingot mold reaches the riser line, pouring is carried out at a speed of 0.02-0.1kg / s.

6. The method for preparing the high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy according to claim 2, characterized in that: Step 4) is specifically as follows: Use a gas furnace to heat the alloy ingot with a temperature below 200°C to 800-900°C and keep it warm for 6-9 hours; After the insulation is completed, the alloy ingot is heated to 1150-1180℃ and subjected to secondary insulation for 5-8 hours; After the secondary heat preservation is completed, the alloy ingot is forged into an initial forging blank with a specification of (200-230 mm)×(200-230 mm)×L, where L is the length of the forging blank and the forging ratio is ≥9; If the temperature of the initial forging billet is lower than 950℃ during the forging process, it should be returned to the furnace for heating and re-forging. Grinding the initial forging blank; Use a gas furnace to heat the initial forging billet with a temperature below 200°C to 800-900°C and keep it at this temperature for 2-3 hours; After the insulation is completed, the initial forging billet is heated to 1120-1140℃ and subjected to secondary insulation for 1-2 hours; After the secondary heat preservation is completed, the initial forging billet is forged into an intermediate forging billet with a specification of φ80-100mm×L, and the forging ratio is ≥5; If the temperature of the intermediate forging billet is lower than 950℃ during the forging process, it should be returned to the furnace for heating and re-forging. Grind the intermediate forging blank; Use a gas furnace to heat the intermediate forging billet with a temperature below 200°C to 800-900°C and keep it warm for 1-2 hours; After the insulation is completed, the intermediate forging billet is heated to 1140-1160℃ and subjected to secondary insulation for 0.5-1.5h. After the secondary heat preservation is completed, the intermediate forging billet is forged into a forging billet with a specification of (φ35-45mm)×L, with a forging ratio of ≥4; the final forging temperature is lower than 950°C.

7. The method for preparing the high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy according to claim 6, characterized in that: When the initial forging billet is cooled, if the temperature of the initial forging billet is higher than 800℃, sand cooling is performed, otherwise, air cooling is performed; When the intermediate forging billet is cooled, if the temperature of the intermediate forging billet is higher than 800℃, sand cooling is performed, otherwise, air cooling is performed; When the forging blank is cooled, if the temperature of the forging blank is higher than 800℃, sand cooling is performed, otherwise, water cooling is performed.

8. The method for preparing the high magnetic permeability and high magnetic induction iron-nickel soft magnetic alloy according to claim 2, characterized in that: In step 5), the specific method of heat treatment is: Place the forging blank in a vacuum heat treatment furnace or a hydrogen atmosphere heat treatment furnace and perform heat treatment on the forging blank in a vacuum or dry hydrogen environment: Heat the forging billet to 1100-1250℃, 1000℃, and 700-800℃ in sequence, and keep them warm for 5-10h, 1-2h, and 0.5-2h respectively; After the insulation is completed, the forging billet is cooled to 500℃ with the furnace, quickly cooled to 150℃, and finally cooled to room temperature with the furnace to complete the heat treatment of the forging billet.

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