CN108251753B

CN108251753B - Fe-Ga-based thin strip with high magnetostriction coefficient and preparation method thereof

Info

Publication number: CN108251753B
Application number: CN201810126561.4A
Authority: CN
Inventors: 沙玉辉; 雷蕃; 左良; 张芳; 和正华
Original assignee: Northeastern University China
Current assignee: Northeastern University China
Priority date: 2018-02-08
Filing date: 2018-02-08
Publication date: 2020-11-20
Anticipated expiration: 2038-02-08
Also published as: CN108251753A

Abstract

The invention relates to a Fe-Ga-based thin strip with a high magnetostriction coefficient and a preparation method thereof. The invention adopts the plate blanks of die casting, plate blank continuous casting, thin slab continuous casting and thin strip continuous casting, and can simply and efficiently carry out mass production by utilizing the traditional rolling and annealing process; establishing an inhibitor system of low-temperature inherent inhibitor and nitriding, and controlling the heat treatment and rolling process to precipitate fine Cu₂S, Nb (C, N) and V (C, N) or composite precipitates thereof as main intrinsic inhibitors, wherein when the intrinsic inhibitors are insufficient, nitrides such as AIN or BN are formed by nitriding before secondary recrystallization annealing, thereby realizing the control of the flexibility of the inhibitors; the fine regulation and control of cold rolling parameters ensure that the primary recrystallization obtains fine and uniform tissues and favorable textures, the coordinated matching of the tissues, the textures and the inhibitor before the secondary recrystallization is realized, and perfect and sharp Goss ({110 }) is obtained<001>) Secondary recrystallization of the texture. The magnetostriction coefficient (3/2) lambdas of the Fe-Ga-based thin strip finished product is as high as 220-370 ppm.

Description

Fe-Ga-based thin strip with high magnetostriction coefficient and preparation method thereof

Technical Field

The invention belongs to the technical field of magnetic materials, and particularly relates to a Fe-Ga-based thin strip with a high magnetostriction coefficient and a preparation method thereof.

Background

The magnetostrictive material is an intelligent material which changes the length thereof under the action of a magnetic field to generate displacement to do work or repeatedly extends and shortens under an alternating magnetic field to generate vibration or sound wave so as to convert electromagnetic energy into mechanical energy or sound energy. The material is widely applied to high and new technical fields of sonar underwater acoustic transducers, electroacoustic transducers, ocean detection and development, micro-displacement driving, vibration reduction and prevention, intelligent mechanisms, automation and the like, and is an important energy and information conversion material.

The magnetostrictive material mainly comprises a rare earth giant magnetostrictive material Tb-Dy-Fe and traditional magnetostrictive materials Fe-Ni, Fe-Al and the like. Tb-Dy-Fe has a large magnetic strain value, but its application range is limited due to intrinsic brittleness and high price. Fe-Ni, Fe-Al and the like have problems of small magnetostriction coefficient, low energy density and the like.

The Fe-Ga (Galfenol) alloy has the characteristics of larger magnetostriction coefficient, high tensile strength, small saturation magnetic field, high magnetic conductivity, low price and the like, so that the Fe-Ga (Galfenol) alloy becomes a magnetostriction material with both large magnetostriction coefficient and excellent mechanical property.

The Fe-Ga alloy has remarkable anisotropy in magnetic elongation, and the magnetostriction coefficient in the <100> direction is the largest, namely, the single crystal lambda 100 is 271 ppm. (S Guruswamy, N Srisukhubbownorchai, A E Clark, J B Restoreff, and M Wun-Fogle, Strong product and low-field-magnetic alloy based on Fe-Ga-script.mat., 2000,43: 239-. Because of the high cost of Fe-Ga alloy single crystal preparation and the high eddy current loss easily generated by using the Fe-Ga alloy single crystal under high frequency condition, a method for preparing a eta (<100>// RD) texture Fe-Ga polycrystalline alloy thin strip based on rolling with high efficiency and low cost needs to be developed. The key technology for preparing the excellent magneto-stretch Fe-Ga thin strip by the rolling method is stable forming and secondary recrystallization texture control.

In 2007, SM Na et al reported rolling Fe_81.3Ga_18.7A small amount of B and S is added into the alloy, and an approximate cubic texture ({001 }is obtained<100>) Or approximately Goss ({110 })<100>) Texture with a maximum magnetostriction coefficient of 220ppm (SM Na, AB Flatau. Secondary recovery crystal lattice)allopathic texture and magnetic interaction in rolled Fe-Ga based alloys.J.appl.Phys. 2007,101:09N 518). 2011, SM Na et al also reported the addition of 1 at% NbC to rolled Fe-Ga at 0.5% H₂The strong Goss ({110 }) is obtained by high-temperature treatment and surface energy induction in Ar gas of S<001>) Texture, magnetostrictive coefficient up to 292ppm (S M Na, A B Flateau.Single grain growing and large magnetic texture in second texture crystallized Fe-Ga in sheet with shared Goss (011) [100 ]]orientation. script. mater, 2012,66: 307-310). In 2015 Yuan et al reported that 0.1 at% NbC was added to Fe-Ga in rolling orientation solidification, and strong Goss texture was obtained by inducing surface energy through S during slow temperature rise of rolled thin strip, and the magnetostriction coefficient reached 245ppm (Chao Yuan, Jiheng Li, Wen lan Zhang, Xiao qian Bao, Xuex gao.Sharp Goss orientation and large magnatic differentiation in the rolled column-grained Fe-Ga alloys.J.Magn.Magn.Mater.,2015,374: 459-.

In the united states patent US2009/0039714a1, Al, Be and more than 1 mol.% NbC are added to Fe-Ga alloy, sheath hot rolling is performed for oxidation prevention, and a Fe-Ga thin strip with η texture is obtained through hot rolling, two-step warm rolling and subsequent heat treatment. Chinese patent CN101465406A, B, Cr, Nb, VC, TiC, MnS, AlN with atomic ratio more than 0.5% and small amount of S, Sn, Sb elements are added, depending on low content (volume ratio 0.001-0.008%) of H₂S or O₂And carrying out long-time heat treatment at the temperature of more than 900 ℃ to obtain a Goss or cubic texture Fe-Ga thin plate. In the Chinese patent CN103014594A, a small amount of Al, Nb, C and B are added as inhibitor forming elements, S is used as a secondary recrystallization inducing element, and a magnetostrictive plate strip with a strong Goss texture is obtained through secondary recrystallization heat treatment and high-temperature heat treatment in a reducing atmosphere.

In the above researches or patents on Fe-Ga magnetostrictive alloy flakes, the inhibitor control is not matched with the secondary recrystallization process, and most of the inhibitor control needs to introduce surface segregation to promote Goss grains to generate perfect secondary recrystallization. The introduction of surface segregation increases the cost and has high equipment precision requirement on one hand, and on the other hand, the annealing at 1200 ℃ or higher temperature is needed to obtain perfect secondary recrystallization and eliminate the adverse effect of S element on the magnetic property, so that the Ga volatilization is serious. Although chinese patent CN 104711475a removes the dependence on surface segregation by adding 5% to 15% mol% Al and performing nitriding twice after hot rolling and cold rolling, a higher Al content lowers the magnetostriction coefficient and the nitriding twice is complicated. The other main reason that the research on the lower magnetostriction performance is that the secondary recrystallization orientation degree is lower, and the key for improving the secondary recrystallization orientation degree is to regulate and control the coordinated matching among the structure, the texture and the inhibitor before secondary recrystallization.

In conclusion, the development of a method for preparing a Fe-Ga-based alloy thin strip with high production efficiency, low cost and stable performance and high magnetostriction coefficient is a problem which needs to be solved urgently at present.

Disclosure of Invention

Aiming at the problems of the existing Fe-Ga alloy preparation technology, the invention provides a preparation method of a Fe-Ga-based thin strip with a high magnetostriction coefficient, which is designed according to the following design thought:

1) the method adopts the die casting, the slab continuous casting, the sheet billet continuous casting and the thin strip continuous casting to prepare the slab simply and efficiently in scale by utilizing the traditional rolling and annealing process;

2) establishing an inhibitor system of low-temperature inherent inhibitor and nitriding, and controlling the heat treatment and rolling process to precipitate fine Cu₂S, AIN, Nb (C, N) and V (C, N) or composite precipitates thereof as a main intrinsic inhibitor; when the inherent inhibition force is insufficient, nitride is formed by nitriding supplement before secondary recrystallization annealing, and a perfect secondary recrystallization structure with sharp texture is obtained by selective induction;

3) and finely regulating and controlling rolling parameters to ensure that primary recrystallization obtains fine and uniform tissues and proper textures.

From the angle of coordination and collocation among the optimized structure, the texture and the inhibitor, the sharp secondary recrystallization Goss texture is obtained, and the hysteresis expansion performance of the Fe-Ga-based alloy thin strip is improved.

The technical scheme of the invention is as follows:

the Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: ga: 15-32%, C: 0.001-0.12%, Al: 0.005-0.08%, Nb: 0.03-0.75%, and the balance of Fe and other inevitable impurities.

Further, the Fe-Ga-based thin strip with the high magnetostriction coefficient also comprises the following components in percentage by weight: cu: less than or equal to 0.5 percent, S: 0.008-0.035%, Mn: 0.01 to 0.3 percent.

Further, the Fe-Ga-based thin strip with the high magnetostriction coefficient also comprises the following components in percentage by weight: sn: 0.02 to 0.1%, Sb: 0.01-0.03%, V: 0.01 to 0.1%, Mo: 0.01-3.0%, Tb: 0.05-0.6%, N: 0.006-0.02% or B: 0.005-0.05% of one or more.

The preparation method of the Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following steps:

step 1: smelting

Smelting according to the set components of the thin strip at the temperature of 1440-1600 ℃, and then casting;

step 2: hot rolling

(1) Heating the blank to 1000-1280 ℃ and preserving heat;

(2) hot rolling the heated and heat-preserved blank at the initial rolling temperature of 900-1250 ℃, the final rolling temperature of 600-1050 ℃, hot rolling for 4-8 times, and the total hot rolling reduction rate of 50-99%, and cooling to obtain a hot rolled plate with the thickness of 1-4 mm;

and step 3: pickling and cold rolling

(1) Pickling the hot rolled plate to remove oxide skin;

(2) carrying out cold rolling on the hot rolled plate after acid washing to obtain a cold rolled thin strip with the thickness of 0.10-1.0 mm;

and 4, step 4: decarburization annealing

Cold rolling thin strip in wet N₂+H₂In the mixed atmosphere, decarburization annealing is carried out at the annealing temperature of 800-1000 ℃ for 2-30 min, and N₂The volume ratio of the water-soluble organic acid is 20-75%;

and 5: secondary recrystallization annealing

And (3) carrying out secondary recrystallization annealing treatment on the annealing plate obtained after decarburization annealing under the condition of inert atmosphere or inert reducing mixed atmosphere to obtain the Fe-Ga-based thin strip with high magnetostriction coefficient.

Further, in step 1, the post-smelting casting may be implemented by any one of die casting, slab casting, thin slab casting and thin strip casting.

Further, in the step 3(1), the hot rolled plate is subjected to normalizing annealing treatment and then is subjected to acid cleaning, wherein the normalizing annealing temperature is 700-1100 ℃, the normalizing annealing time is 2-120 min, and the plate is subjected to rapid cooling after normalizing.

Further, the cold rolling in step 3(2) includes the following two rolling methods, and any one of the rolling methods may be used for cold rolling:

a primary rolling method: firstly, performing warm cold rolling at room temperature to 800 ℃ and the reduction rate of 30-95%, and then performing cold rolling at a lower temperature of room temperature to 600 ℃ and the reduction rate of 10-92%;

a secondary rolling method: the first cold rolling is carried out at room temperature to 800 ℃ and the reduction rate of 30-95%, then the steel is annealed at 800-1100 ℃ for 5-120 min and then rapidly cooled, and the second cold rolling is carried out at a lower temperature of room temperature to 600 ℃ and the reduction rate of 50-92%.

Further, the secondary recrystallization annealing treatment in the step 5 includes the following two modes:

the first mode is as follows: heating the annealing plate from 600-900 ℃ to 1000-1200 ℃ and preserving heat for 0.5-10 h, wherein the heating process adopts continuous heating or multi-section annealing containing intermediate heat preservation

And a second mode: and annealing the annealed plate at 900-1200 ℃ for 15-600 min at constant temperature.

Further, the inert atmosphere in step 5 refers to a nitrogen atmosphere or an argon atmosphere; the inert reducing mixed atmosphere refers to the mixed atmosphere of inert gas and hydrogen.

Further, in the secondary recrystallization annealing treatment in step 5, after the secondary recrystallization annealing is completed, the cooling may be performed by any one of furnace cooling, air cooling, and quenching.

The second preparation method of the Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following steps:

step 1: smelting

step 2: hot rolling

(1) Heating the blank to 1000-1280 ℃ and preserving heat;

and step 3: pickling and cold rolling

(1) Pickling the hot rolled plate to remove oxide skin;

and 4, step 4: decarburization annealing

Cold rolling thin strip in wet N₂+H₂The mixed atmosphere of (A) and (B) is subjected to decarburization annealing at the annealing temperature of 800-1000 ℃ for 2-30 min, and N₂The volume ratio of the water-soluble organic acid is 20-75%;

and 5: nitriding treatment

Putting thin strips in dry NH₃+N₂+H₂Performing nitriding treatment in the mixed atmosphere;

step 6: secondary recrystallization annealing

And (3) carrying out secondary recrystallization annealing treatment on the annealing plate obtained by decarburization annealing under the condition of inert atmosphere or inert reducing mixed atmosphere to obtain the Fe-Ga-based thin strip with high magnetostriction coefficient.

a primary rolling method: firstly, carrying out warm cold rolling at the rolling temperature of room temperature-800 ℃ and the reduction rate of 30-95%, and then carrying out warm cold rolling at the lower temperature of room temperature-600 ℃ and the reduction rate of 10-92%;

Further, a nitriding treatment process described in step 5; the NH₃+N₂+H₂In a mixed atmosphere of H₂50-80% of NH₃The nitriding temperature is 600-1050 ℃, the nitriding time is 10-500 s, and the nitriding amount is 30-800 ppm.

Further, the secondary recrystallization annealing treatment in step 6 includes the following two modes:

Further, the inert atmosphere in step 6 refers to a nitrogen atmosphere or an argon atmosphere; the inert reducing mixed atmosphere refers to the mixed atmosphere of inert gas and hydrogen, and the mixing proportion is any proportion.

Further, in the secondary recrystallization annealing treatment in step 6, after the secondary recrystallization annealing is completed, the cooling may be performed by any one of furnace cooling, air cooling, and quenching.

Further, the nitriding treatment of step 5 may be performed before the decarburization annealing, after the decarburization annealing, or simultaneously with the decarburization annealing

The principle of the invention is as follows:

the Fe-Ga based thin strip with high magnetostriction coefficient can be formed by respectively containing 0.001-0.12% of C and 0.006-0.02% of N by weightNb(C,N)、V(C,N)、Fe₃C. The AlN precipitates suppress primary recrystallized grains, the cold rolling process also promotes shear band formation, the Goss grain nucleation sites are increased, and a certain amount of C also contributes to the improvement of the magnetostriction coefficient of the Fe-Ga alloy.

The Al content is 0.005-0.08 wt%. When the inhibition force of the inherent inhibitor is insufficient, Al reacts with N to generate an AIN precipitation phase in the nitriding treatment process, and the AIN precipitation phase is used as the inhibitor to inhibit matrix grains in the later stage of slow temperature rise. An Al content of less than 0.005% makes the suppression insufficient, and an Al content of more than 0.08% makes the suppression too high, which is also disadvantageous in the magnetostriction property.

The weight percentage content of Cu and S is respectively less than or equal to 0.5 percent and 0.008-0.035 percent. Cu formation during hot rolling and subsequent heat treatment₂S, as an inherent inhibitor, inhibits the matrix grains during the slow temperature rise. Their low solid solution temperature is beneficial to reducing the heating temperature of the slab.

The content of B is 0.005-0.05% by weight. The plasticity is improved by refining crystal grains and improving grain boundary bonding force, and the BN strengthening inhibition force can also be formed.

The Mn content is 0.01-0.3 wt%. Mn plays a role in desulfurization and forms MnS mass points to pin crystal grains to grow.

The Nb and V are 0.03-0.75% and 0.01-0.1% by weight, respectively. The plasticity is improved by refining the structure and improving the bonding force of grain boundaries, and the grain growth can be inhibited by solid solution and formation of Nb (C, N) and V (C, N).

The weight percentage content of Sn and Sb is 0.01-0.1% and 0.01-0.03%, respectively. The grain boundary segregation element can assist in enhancing the suppression force.

The weight percentage content of Mo is 0.01-3.0%. The method is favorable for improving plasticity and homogenizing primary recrystallization grains; mo can be enriched on the surface to prevent the oxidation of grain boundaries when the plate blank is heated at high temperature, and the ductility is enhanced.

The Tb accounts for 0.05-0.6 wt%. The precipitated phase can assist in pinning the movement of a grain boundary and can also improve the magnetostriction coefficient by generating lattice distortion and influencing phase change.

When the preparation method of the Fe-Ga-based thin strip with high magnetostriction coefficient adopts the processes of die casting, slab casting and sheet billet casting, the temperature is kept above 1000 ℃ before hot rolling to ensure that coarse Cu is obtained₂S, Nb (C, N) and V (C, N), etc., are completely or partially dissolved in a solid solution, and then a large number of fine precipitates are induced by deformation during hot rolling and subsequent heat treatment, thereby increasing the strength of the intrinsic retarder.

When the method for preparing the Fe-Ga-based thin strip with the high magnetostriction coefficient is adopted, the characteristic of sub-rapid solidification (the solidification speed can reach 10) of the thin strip continuous casting is utilized²～10⁴The temperature is higher than the second temperature, and the temperature is higher than the second temperature.

In the cold rolling process, different rolling temperatures and reduction ratios are adopted, favorable recrystallization texture and structure characteristics are obtained from the angle of regulating and controlling the deformation microstructure, and particularly, the number and deviation angle of primary recrystallization Goss crystal nuclei are regulated and controlled to improve the accuracy of secondary recrystallization. The addition of Nb, V and other elements has great influence on the nucleation and growth of recrystallization, and is favorable for obtaining fine and uniform primary recrystallization texture and favorable primary recrystallization texture. Different inhibitor systems and contents are formed, and complete secondary recrystallization can be realized only by matching different primary recrystallization textures and textures. Therefore, the cold rolling parameters need to be regulated and controlled to realize the coordination and matching of the texture, the texture and the restraining force.

The nitriding process aims to form nitrides such as AlN or BN and the like before secondary recrystallization so as to supplement the inhibition force, the growth of matrix grains can be effectively inhibited in the high-temperature annealing process, the Goss grains can be perfectly recrystallized at a proper temperature range accurately, and excellent magnetostriction performance is obtained. When the control of the inherent inhibitor meets the requirement, the nitriding treatment process can be omitted, but the appropriate amount of nitriding is beneficial to the final product to have more excellent magnetostriction performance.

The secondary recrystallization annealing process regulates and controls an annealing system, a heating rate and an annealing atmosphere, aims to match the inhibition force decline with the accurate Goss abnormal growth process, and is important for controlling the secondary recrystallization perfection and the orientation degree.

Compared with the prior art, the Fe-Ga-based thin strip with high magnetostriction coefficient and the preparation method thereof have the beneficial effects that:

1. the method adopts die casting, slab continuous casting, sheet billet continuous casting and thin strip continuous casting, and utilizes the traditional rolling and annealing process flow to stably and efficiently prepare the Fe-Ga alloy thin strip with the sharp Goss secondary recrystallization texture and the large hysteresis expansion coefficient, thereby improving the production efficiency and reducing the production cost.

2. By adopting the design of inherent inhibitor or additionally obtained inhibitor, fine Cu is precipitated by the heat treatment and rolling process₂S, AIN, Nb (C, N) and V (C, N) or complex precipitates thereof as main intrinsic inhibitors. When the inherent inhibition force is insufficient, the nitriding process is timely adjusted to form supplementary inhibition force of nitrides such as AIN or BN, and the like, and the flexible control of the inhibition force is realized by combining the regulation and control of secondary recrystallization annealing atmosphere. From the angle of coordination and matching of an optimized inhibitor, a structure and a texture, perfect secondary recrystallization with sharp orientation is obtained by utilizing the selective growth advantage of Goss grains;

3. the cold rolling parameters are finely regulated, fine and uniform tissues and favorable textures are obtained by primary recrystallization, and the orientation degree of secondary recrystallization grains is improved, so that the hysteresis expansion coefficient of the Fe-Ga alloy is improved.

4. The stable forming and texture control are realized by reasonably controlling the components and the process parameters, and finally the finished Fe-Ga thin strip with the thickness of 0.1-1.0 mm is obtained, wherein the magnetostriction coefficient (3/2) lambda s of the finished Fe-Ga thin strip is as high as 220-370 ppm.

In conclusion, the method for preparing the Fe-Ga-based thin strip with the high magnetostriction coefficient by the rolling method realizes the efficient and low-cost preparation of the Fe-Ga-based alloy thin strip with the high orientation degree by the rolling method under the control of the inhibitor and the coordination and matching of the inhibitor with the structure and the texture, and has wide application prospect.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is to be understood that the drawings in the following description are only some of the embodiments described in the present application.

FIG. 1 is a schematic flow chart of a method for preparing a Fe-Ga-based thin strip with a high magnetostriction coefficient according to the present invention;

FIG. 2 is an ODF constant of a sample obtained by subjecting a 4 th group of Fe-Ga based thin strips having high magnetostriction coefficients in Table 2 of example 2 of the present invention to secondary recrystallization annealing

A cross-sectional view;

FIG. 3 is a microstructure diagram of a high magnetostriction coefficient Fe-Ga based thin strip sample after decarburization annealing in example 6 of the present invention, wherein the horizontal direction is RD direction and the vertical direction is TD direction.

FIG. 4(a) is a microstructure diagram of a group 3 high magnetostriction coefficient Fe-Ga based thin strip of example 8 of the present invention after secondary recrystallization annealing;

FIG. 4(b) is a microstructure diagram of a group 4 high magnetostriction coefficient Fe-Ga based thin strip in example 8 of the present invention after secondary recrystallization annealing.

Detailed Description

The technical solution of the present invention will be further specifically described below with reference to examples.

Example 1

The Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: c: 0.03%, Al: 0.03%, Nb: 0.25%, Cu: 0.5%%, Mn: 0.08%, S: 0.02%, Sn: 0.06%, Mo: 0.5%, the balance being Fe and other unavoidable impurities, the Ga contents being different as shown in Table 1.

step 1, smelting:

respectively smelting at 1440-1600 ℃ according to the set components of the thin strips in the table 1, and then casting;

step 2, hot rolling:

(1) heating the blank to 1100-1280 ℃ and preserving heat;

(2) hot rolling the heated and heat-preserved blank at the initial rolling temperature of 1150-1200 ℃, and cooling to obtain a hot rolled plate with the thickness of 2.5 mm;

step 3, acid washing and cold rolling:

(1) pickling the hot rolled plate;

(2) and (3) cold rolling the hot rolled plate after acid washing, and obtaining a cold rolled thin strip with the thickness of 0.25mm by adopting a secondary rolling method, wherein:

a secondary rolling method: the first cold rolling is carried out at the rolling temperature of 400-800 ℃ and the reduction rate of 40%, then the steel is annealed at 950 ℃ for 40min and then rapidly cooled, and the second cold rolling is carried out at the lower temperature of 300 ℃ and the reduction rate of 83%;

step 4, decarburization annealing:

cold rolled thin strip is processed at wet volume ratio of 25% N₂+75％H₂The decarburization annealing is carried out in the mixed atmosphere, the annealing temperature is 850 ℃, and the annealing time is 4 min;

and step 5, nitriding treatment:

the thin strip is dried and the volume ratio is 10 percent NH₃+20％N₂+70％H₂Nitriding treatment is carried out in mixed atmosphere, the nitriding temperature is 900 ℃, and the nitriding amount is 160 ppm;

and 6, secondary recrystallization annealing:

the results of measuring the magnetostriction coefficient (3/2) λ s of the high magnetostriction coefficient Fe-Ga based ribbon prepared with different Ga contents are shown in Table 1, wherein the result is obtained by heating the annealing plate from 800 ℃ to 950 ℃ at a speed of 20 ℃/h and keeping the temperature for 2h, then heating to 1150 ℃ at a speed of 15 ℃/h and keeping the temperature for 4h, and air-cooling.

TABLE 1 comparison table of magnetostriction coefficients of Fe-Ga-based thin strips with high magnetostriction coefficients prepared by different Ga contents

Serial number	Ga content (heavy)% by weight	Degree of completion of secondary recrystallization (%)	(3/2)λs(ppm)
				1	15.0	100	220
2	17.2	100	280
				3	21.8	100	310
4	22.6	100	355
				5	23.5	100	342
6	27.1	100	295
				7	32.0	100	330

As can be seen from Table 1, when the secondary recrystallization is developed perfectly, the Ga content becomes one of the key factors influencing the hysteresis performance, and the result is consistent with the influence of the Ga content on the single crystal magnetostriction coefficient, thereby fully explaining the importance of accurately controlling the Ga content on the hysteresis performance of the Fe-Ga alloy.

Example 2

The Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: 22.3%, the other components are shown in table 2, and the balance is Fe and other unavoidable impurities.

step 1, smelting:

respectively smelting at 1440-1600 ℃ according to the set components of the thin strips in the table 2, and then casting;

step 2, hot rolling:

(1) heating the blank to 1100-1250 ℃ and preserving heat;

(2) hot rolling the heated and heat-preserved blank at the initial rolling temperature of 1100-1200 ℃, and cooling to obtain a hot rolled plate with the thickness of 2.3 mm;

step 3, acid washing and cold rolling:

(1) pickling the hot rolled plate;

(2) and (3) cold rolling the hot rolled plate after acid washing, and obtaining a cold rolled thin strip with the thickness of 0.2mm by adopting a secondary rolling method, wherein:

a secondary rolling method: the first cold rolling is carried out at the rolling temperature of 400-800 ℃ and the reduction rate of 56%, then the steel is annealed at 900 ℃ for 30min and then rapidly cooled, and the second cold rolling is carried out at the lower temperature, the rolling temperature is 200 ℃ and the reduction rate is 80%;

step 4, decarburization annealing:

cold rolled thin strip is processed at wet volume ratio of 25% N₂+75％H₂The decarburization annealing is carried out in the mixed atmosphere, the annealing temperature is 875 ℃, and the annealing time is 5 min;

and step 5, nitriding treatment:

thin strips, 15% NH in dry volume₃+15％N₂+70％H₂Nitriding treatment is carried out in mixed atmosphere, the nitriding temperature is 800 ℃, and the nitriding amount is 180 ppm;

and 6, secondary recrystallization annealing:

the results of heating the annealed sheet from 800 ℃ to 1200 ℃ at a rate of 20 ℃/h under an inert reducing atmosphere for 2 hours, quenching the heated sheet to obtain a high magnetostriction coefficient Fe-Ga based ribbon, and measuring the magnetostriction coefficient (3/2). lambda.s of the high magnetostriction coefficient Fe-Ga based ribbons having different compositions and contents are shown in Table 2.

ODF constancy of samples obtained after secondary recrystallization annealing of group 4 high magnetostriction coefficient Fe-Ga-based thin strips in Table 2

Cross-section as shown in figure 2.

TABLE 2 comparison of magnetic elongation properties of Fe-Ga based thin strips with high magnetostriction coefficients of different compositions and contents

From fig. 2, it can be seen that a single sharp Goss texture is obtained after the secondary recrystallization, so that the magnetostriction coefficient reaches 327ppm, which indicates that the control level of the secondary recrystallization texture is one of the keys for determining the magnetostriction performance of the Fe-Ga alloy.

The 10 th to 12 th groups in table 2 are comparative experiments, and it can be seen from table 2 that when the weight percentage content of the components of the Fe-Ga alloy ribbon is within the range of the present invention (serial number 1 to 9), effective control of the inhibitor is realized by controlling precipitation and nitriding, secondary crystallization is promoted to be more perfect, and hysteresis expansion and contraction performance is improved. On the contrary, when the weight percentage content of the components of the Fe-Ga alloy thin strip exceeds the range of the invention (comparison experiment 10-12), the strength of the restraining force is too strong or too weak, ideal secondary recrystallization is difficult to obtain, and the magnetostriction performance is lower.

Example 3

The Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: ga: 20.4%, C: 0.05%, Nb: 0.1%, Cu: 0.2%%, Mn: 0.08%, S: 0.015%, Mo: 0.05%, Tb: 0.3, the balance being Fe and other unavoidable impurities, and the Al contents being different as shown in Table 3.

step 1, smelting:

respectively smelting and then casting at 1440-1600 ℃ according to the set components of the thin strips in the table 3;

step 2, hot rolling:

(1) heating the blank to 1100-1280 ℃ and preserving heat;

(2) hot rolling the heated and heat-preserved plate blank at the rolling start temperature of 1150 ℃, and cooling to obtain a hot rolled plate with the thickness of 4 mm;

step 3, acid washing and cold rolling:

(1) carrying out acid washing on the hot rolling to remove oxide skin;

(2) carrying out normalizing annealing on a hot rolled plate at 1050 ℃, then carrying out rapid cooling, wherein the annealing time is 5min, and then adopting a one-step rolling method, wherein the rolling temperature is 400 ℃, and the reduction rate is 75%, so as to obtain a cold rolled thin strip with the thickness of 1.0 mm;

step 4, decarburization annealing:

cold-rolled thin strip is processed at a wet volume ratio of 20% N₂+80％H₂The decarburization annealing is carried out in the mixed atmosphere, the annealing temperature is 830 ℃, and the annealing time is 8 min;

and step 5, nitriding treatment:

thin strips, 20% NH in dry volume₃+20％N₂+70％H₂Nitriding treatment is carried out in mixed atmosphere, the nitriding temperature is 700 ℃, the nitriding time is 120s, and the nitriding amount is 300 ppm;

and 6, secondary recrystallization annealing:

the results of measuring the magnetostriction coefficient (3/2) λ s of the high magnetostriction coefficient Fe — Ga based thin strip with different Al contents by heating the annealed sheet from 600 ℃ to 850 ℃ at a rate of 50 ℃/h, then to 1000 ℃ at a rate of 20 ℃/h, then to 1200 ℃ at a rate of 15 ℃/h under an inert reducing mixed atmosphere, and quenching to obtain a high magnetostriction coefficient Fe — Ga based thin strip are shown in table 3.

TABLE 3 comparison table of magnetostriction coefficients of Fe-Ga-based thin strips with high magnetostriction coefficients prepared with different Al contents

Serial number	Al content (% by weight)	Degree of completion of secondary recrystallization (%)	(3/2)λs(ppm)
				1	0.005	100	290
2	0.02	100	295
				3	0.03	100	320
4	0.05	100	325
				5	0.065	100	310
6	0.08	100	290
				Comparative experiment 7	0.2	40％	195

Group 7 in table 3 is a comparative experiment, and it can be seen from table 3 that when the Al content is within the range of the present invention (No. 1-6), the secondary recrystallization is completed well and the magnetostriction property is excellent; when the Al content is out of the range of the present invention (comparative experiment 7), the secondary recrystallization completion degree is lowered, and therefore the magnetostriction property is low.

Example 4

The Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: ga: 31.5%, C: 0.06%, Al: 0.01%, and the balance of Fe and other unavoidable impurities, and the Nb content was varied as shown in Table 4.

step 1, smelting:

respectively smelting at 1440-1600 ℃ according to the set components of the thin strips in the table 4, and then casting;

step 2, hot rolling:

(1) heating the blank to 1100-1250 ℃ and preserving heat;

(2) hot rolling the heated and heat-preserved blank at the initial rolling temperature of 1150-1200 ℃, and cooling to obtain a hot rolled plate with the thickness of 1.8 mm;

step 4, acid washing and cold rolling:

(1) pickling the hot rolled plate;

(2) carrying out normalization annealing on a hot rolled plate at 1000 ℃, then carrying out rapid cooling, wherein the annealing time is 8min, carrying out warm cold rolling at 700 ℃ by adopting a one-step rolling method, and then carrying out warm cold rolling at a lower temperature of 200 ℃ and a reduction rate of 85% to obtain a cold rolled thin strip with the thickness of 0.15 mm;

step 5, decarburization annealing:

and 6, secondary recrystallization annealing:

the results of measuring the magnetostriction coefficient (3/2). lamda.s of the high magnetostriction coefficient Fe-Ga based ribbons with different Nb contents are shown in Table 4, in which the annealed sheet is heated from 900 ℃ to 1000 ℃ at a rate of 30 ℃/h and heat-preserved for 4 hours, then heated to 1100 ℃ at a rate of 10 ℃/h and heat-preserved for 5 hours, and the furnace is cooled to obtain the high magnetostriction coefficient Fe-Ga based ribbons.

TABLE 4 comparison of magnetostriction coefficients of Fe-Ga-based thin strips with high magnetostriction coefficients prepared with different Nb contents

Categories	Nb content (% by weight)	Degree of completion of secondary recrystallization (%)	(3/2)λs(ppm)
				Comparative experiment 1	0.01	25	170
2	0.03	100	285
				3	0.1	100	292
4	0.28	100	345
				5	0.42	100	314
6	0.56	100	310
				7	0.74	100	292
Comparative experiment 8	1.52	15	156

The 1 st group and the 8 th group in the table 4 are comparative experiments, and it can be seen from the table 4 that when the Nb content is within the range of the present invention (serial number 2-7), the coordination of the inhibition force, the texture and the texture can be realized, sharp and perfect Goss secondary recrystallization texture is obtained, and the magnetostriction performance is excellent; when the Nb content is out of the range of the present invention (comparative experiments 1 and 8), the secondary recrystallization completion degree is lowered, and therefore the magnetostriction property is low.

Example 5

The Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: ga: 17%, C: 0.03%, Al: 0.048%, Nb: 0.45%, Cu: 0.5%%, Mn: 0.08%, S: 0.02%, Sn: 0.06%, Mo: 0.5%, the balance being Fe and other unavoidable impurities, the B contents being different as shown in Table 5.

step 1, smelting:

smelting and then casting at 1440-1600 ℃ according to the set components of the thin strip in the table 5;

step 2, hot rolling:

(1) heating the blank to 1100-1250 ℃ and preserving heat;

(2) hot rolling the heated and heat-preserved blank at the initial rolling temperature of 1150-1200 ℃, and cooling to obtain a hot rolled plate with the thickness of 2 mm;

step 3, acid washing and cold rolling:

(1) pickling the hot rolled plate;

a secondary rolling method: the first cold rolling is carried out at the rolling temperature of 400-800 ℃ and the reduction rate of 60%, then the steel is annealed at the temperature of 1000 ℃ for 10min and then rapidly cooled, and the second cold rolling is carried out at the lower temperature, the rolling temperature is 600 ℃ and the reduction rate is 75%;

step 4, decarburization annealing:

cold-rolled thin strip is processed at a wet volume ratio of 30% N₂+70％H₂In a mixed atmosphere ofPerforming decarburization annealing at 900 ℃ for 15 min;

and 5, secondary recrystallization annealing:

the results of measuring the magnetostriction coefficient (3/2). lamda.s of the high magnetostriction coefficient Fe-Ga based ribbons having different B contents, in which the annealed sheet was heated from 800 ℃ to 900 ℃ at a rate of 120 ℃/h under the condition of an inert reducing mixed atmosphere, then heated to 1200 ℃ at a rate of 60 ℃/h and kept warm for 2h, and air-cooled, were shown in Table 5.

TABLE 5 comparison table of magnetostriction coefficients of Fe-Ga-based thin strips with high magnetostriction coefficients prepared with different B contents

Serial number	B content (% by weight)	Degree of completion of secondary recrystallization (%)	(3/2)λs(ppm)
				1	0.005	100	228
2	0.015	100	240
				3	0.03	100	256
4	0.04	100	247
				5	0.05	100	243
Comparative experiment 6	0.5	10	120

Group 6 in table 5 is a comparative experiment, and it can be seen from table 5 that when the B content is within the range of the present invention (No. 1-5), the secondary recrystallization is completed well and the magnetostriction property is excellent; when the content of B is out of the range of the present invention (comparative experiment 6), the secondary recrystallization completion is lowered and the magnetostriction property is low.

Example 6

The Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: ga: 23.5%, C: 0.025%, Nb: 0.054%, Al: 0.035%, Cu: 0.1%%, Mn: 0.05%, S: 0.02%, Sn: 0.06%, V: 0.05%, and the balance of Fe and other unavoidable impurities.

step 1, smelting:

respectively smelting at 1440-1600 ℃ according to the set components of the thin strip, and then casting;

step 2, hot rolling:

(1) heating the blank to 1100-1280 ℃ and preserving heat;

(2) hot rolling the heated and heat-preserved blank at the beginning temperature of 1190 ℃, and cooling to obtain a hot rolled plate with the thickness of 2 mm;

step 3, acid washing and cold rolling:

(1) pickling the hot rolled plate to remove oxide skin;

(2) firstly, carrying out warm cold rolling on a hot rolled plate by adopting a one-step rolling method, wherein the rolling temperature is 500 ℃, the reduction rate is 40%, and then carrying out warm cold rolling at a lower temperature, the rolling temperature is 100 ℃, and the reduction rate is 70%, so as to obtain a cold-rolled thin strip with the thickness of 0.35 mm;

step 4, decarburization annealing:

cold-rolled thin strip is processed at a wet volume ratio of 20% N₂+80％H₂The decarburization annealing is carried out in the mixed atmosphere, the annealing temperature is 870 ℃, the annealing time is 5min, and the microstructure diagram of the base strip sample after the decarburization annealing is shown in figure 3;

and step 5, nitriding treatment:

the thin strip is dried at a volume ratio of 25% NH₃+20％N₂+55％H₂Nitriding treatment is carried out in mixed atmosphere, the nitriding temperature is 870 ℃, and the nitriding amount is different as shown in Table 6;

and 6, secondary recrystallization annealing:

heating the annealing plate from 850 ℃ to 950 ℃ at the speed of 30 ℃/h under the condition of inert reducing mixed atmosphere, then heating to 1150 ℃ at the speed of 20 ℃/h, preserving heat for 6h, and quenching to obtain the Fe-Ga-based thin strip with high magnetostriction coefficient. The results of measuring the magnetostriction coefficient (3/2). lamda.s of the Fe-Ga based thin strip having a high magnetostriction coefficient obtained by varying the nitriding amount in the nitriding treatment are shown in Table 6.

TABLE 6 comparison of magnetostriction coefficients of Fe-Ga-based thin strips with high magnetostriction coefficients prepared by different nitriding amounts

Serial number	Amount of nitriding (ppm)	(3/2)λs(ppm)
			1	30	265
2	100	302
			3	160	345
4	380	320
			5	560	356
6	800	290
			Comparative experiment 7	1000	80

As can be seen from FIG. 3, a uniform primary recrystallized structure is obtained after the decarburization annealing, which is advantageous for the completion of the secondary recrystallization.

As can be seen from Table 6, when the nitriding amount is too low (number 1-6), the complementary formation inhibiting force is insufficient, the secondary recrystallization is incomplete, and the magnetostriction property is low; when the nitriding amount is too high (comparative experiment 7), the supplementary suppression force is too strong to be favorable for secondary recrystallization, resulting in lower magnetostriction performance.

Example 7

The Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: ga: 22.0%, C: 0.05%, Al: 0.03%, Nb: 0.25%, Sn: 0.05%, V: 0.1, Mo: 0.1%, and the balance of Fe and other unavoidable impurities.

step 1, smelting:

smelting according to the set components of the thin strip at 1420-1600 ℃, and then casting;

step 2, hot rolling:

(1) heating the blank to 1100-1280 ℃ and preserving heat;

(2) hot rolling the heated and insulated blank at the initial rolling temperature of 1180 ℃ to obtain a hot rolled plate with the thickness of 3mm after cooling;

step 3, acid washing and cold rolling:

(1) pickling the hot rolled plate;

(2) carrying out cold rolling on the hot rolled plate after acid washing, adopting a secondary rolling method, wherein the first time is warm cold rolling, the rolling temperature is 400-800 ℃, the reduction rate is 66%, then carrying out intermediate annealing and then carrying out rapid cold rolling, the second time is low-temperature cold rolling, the rolling temperature is 200-600 ℃, the reduction rate is 80%, and the intermediate annealing temperature is different as shown in Table 7, so that a cold-rolled thin strip with the thickness of 0.2mm is obtained;

step 4, decarburization annealing:

cold rolled thin strip is processed at wet volume ratio of 25% N₂+75％H₂The decarburization annealing is carried out in the mixed atmosphere, the annealing temperature is 850 ℃, the annealing time is 8 min:

and 5, secondary recrystallization annealing:

heating the annealing plate from 800 ℃ to 1200 ℃ at the speed of 30 ℃/h under the condition of inert reducing mixed atmosphere, preserving heat for 2h, and quenching to obtain the Fe-Ga-based thin strip with high magnetostriction coefficient.

The results of the magnetostriction coefficient (3/2). lamda.s of the Fe-Ga based thin strip having a high magnetostriction coefficient obtained by the double rolling method with different interannealing temperatures are shown in Table 7.

TABLE 7 comparison table of magnetostriction coefficients of Fe-Ga based thin strips with high magnetostriction coefficients prepared at different annealing temperatures

Serial number	Intermediate annealing temperature	Time of intermediate annealing	(3/2)λs(ppm)
				1	800	30	285
2	900	10	290
				3	900	30	300
4	950	30	320
				5	1050	10	340
Comparative experiment 6	1150	10	180

Group 6 in Table 7 is a comparative experiment, and it can be seen from Table 7 that when the interannealing schedule is within the range of the present invention (No. 1-5), excellent magnetostriction property can be obtained; when the interannealing schedule is out of the range of the present invention (comparative experiment 6), the magnetostriction property is low.

Example 8

The Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: ga: 19%, C: 0.03%, Nb: 0.15%, Al: 0.01%, Sn: 0.06%, V: 0.1%, B: 0.02%, Tb: 0.2%, and the balance of Fe and other unavoidable impurities.

step 1, smelting:

step 2, hot rolling:

(1) heating the blank to 1100-1280 ℃ and preserving heat;

(2) hot rolling the heated and heat-preserved blank at the beginning temperature of 1200 ℃, and cooling to obtain a hot rolled plate with the thickness of 2.2 mm;

step 3, acid washing and cold rolling:

(1) pickling the hot rolled plate to remove oxide skin;

(2) cold rolling the hot rolled plate after acid washing, and obtaining cold rolled thin strips with the thickness of 0.45mm, 0.35mm, 0.25mm, 0.15mm and 0.1mm by adopting a secondary rolling method, wherein the secondary rolling method comprises the following steps: the first cold rolling is carried out at the rolling temperature of 400-800 ℃ and the reduction rate of 55%, then the steel is annealed at 1025 ℃ for 30min and then rapidly cooled, and the second cold rolling is carried out at the lower temperature of 500 ℃ and the reduction rates are different as shown in Table 8;

and 4, nitriding treatment:

cold rolling thin strip with 5% NH in dry volume ratio₃+20％N₂+75％H₂Nitriding treatment is carried out in mixed atmosphere, the nitriding temperature is 950 ℃, the nitriding time is 40s, and the nitriding amount is 280 ppm;

step 5, decarburization annealing:

subjecting the nitrided thin strip to a wet volume ratio of 25% N₂+75％H₂The decarburization annealing is carried out in the mixed atmosphere, the annealing temperature is 850 ℃, and the annealing time is 5 min;

and 6, secondary recrystallization annealing:

heating the annealing plate from 800 ℃ to 1025 ℃ at the speed of 20 ℃/h under the condition of inert reducing mixed atmosphere, then heating to 1100 ℃ at the speed of 15 ℃/h, then heating to 1200 ℃ at the speed of 120 ℃/h, preserving heat for 2h, and quenching to obtain the Fe-Ga-based ribbon with high magnetostriction coefficient.

The results of the magnetostriction coefficient (3/2) λ s of the Fe-Ga based thin strip having a high magnetostriction coefficient obtained by the secondary rolling method with different reduction ratios in the secondary cold rolling are shown in Table 8.

TABLE 8 comparative table of magnetostriction coefficients of Fe-Ga-based thin strips with high magnetostriction coefficients prepared at different rolling reductions

Serial number	Finished product thickness (mm)	Second Cold Rolling reduction (%)	(3/2)λs(ppm)
				1	0.45	55	280
2	0.35	65	325
				3	0.25	75	345
4	0.15	85	350
				5	0.1	90	290

In Table 8, the macrostructure diagram of the Fe-Ga based thin strip sample of the group 3 after secondary recrystallization annealing is shown in figure 4(a), and the macrostructure diagram of the Fe-Ga based thin strip sample of the group 4 after secondary recrystallization annealing is shown in figure 4 (b); it can be seen from fig. 4 that centimeter-level perfect secondary crystal grains are obtained after high-temperature annealing, the hysteresis elasticity is excellent, and the importance of secondary recrystallization control on the hysteresis elasticity is further illustrated. It can be seen from Table 8 that the secondary cold rolling reduction ratio is within the range of the present invention to obtain excellent hysteresis expansion and contraction properties.

Example 9

The Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: ga: 24.6%, C: 0.07%, Nb: 0.38%, Al: 0.045%, Cu: 0.1%%, Mn: 0.05%, S: 0.01%, V: 0.08%, and the balance of Fe and other inevitable impurities.

step 1, smelting:

step 2, hot rolling:

(1) heating the blank to 1100-1280 ℃ and preserving heat;

(2) hot rolling the heated and heat-preserved blank at the beginning temperature of 1200 ℃, and cooling to obtain a hot rolled plate with the thickness of 2.0 mm;

step 3, acid washing and cold rolling:

(1) pickling the hot rolled plate to remove oxide skin;

(2) carrying out normalization annealing on the hot rolled plate at 1025 ℃, then carrying out rapid cooling, wherein the annealing time is 5min, and then adopting a one-step rolling method to obtain a cold rolled thin strip with the thickness of 0.35mm, wherein:

a primary rolling method: firstly, carrying out warm cold rolling at the rolling temperature of 700 ℃ and the reduction rate of 58%, and then carrying out warm cold rolling at the lower temperature of 200 ℃ and the reduction rate of 77%;

step 4, decarburization annealing and nitriding treatment:

the cold rolled thin strip is processed at a wet volume ratio of 15% NH₃+20％N₂+65％H₂The decarburization annealing and the nitriding treatment are simultaneously carried out in the mixed atmosphere, the annealing temperature is 870 ℃, the annealing time is 2min, and the nitriding amount is 286 ppm;

and 5, secondary recrystallization annealing:

the annealed sheet was heated from 800 ℃ to 1200 ℃ at different heating rates shown in Table 9 under an inert reducing atmosphere and kept for 4 hours, and the sheet was cooled in a furnace to obtain a Fe-Ga based ribbon having a high magnetostriction coefficient, and the results of measuring the magnetostriction coefficient (3/2). lambda.s were shown in Table 9.

TABLE 9 comparison table of magnetostriction coefficients of Fe-Ga-based thin strips with high magnetostriction coefficients prepared at different heating rates

Categories	Rate of temperature rise (. degree. C./h)	(3/2)λs(ppm)
			1	10	295
2	25	305
			3	50	312
4	70	289
			5	120	260
Comparative experiment 6	200	189

Group 6 in table 9 is a comparative experiment, and it can be seen from table 9 that when the temperature rise rate is within the range of the present invention (No. 1-5), excellent magnetostrictive performance can be obtained; when the temperature rising rate is out of the range of the present invention (comparative experiment 6), the magnetostrictive property is low.

Example 10

The Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: ga: 23.2%, C: 0.065%, Nb: 0.59%, Al: 0.005%, Cu: 0.05%%, Mn: 0.05%, S: 0.01%, Sn: 0.04%, and the balance of Fe and other unavoidable impurities.

step 1, smelting:

step 2, hot rolling:

(1) heating the blank to 1100-1280 ℃ and preserving heat;

(2) hot rolling the heated and insulated blank at the initial rolling temperature of 1180 ℃ to obtain a hot rolled plate with the thickness of 2.3mm after cooling;

step 3, acid washing and cold rolling:

(1) pickling the hot rolled plate to remove oxide skin;

(2) carrying out cold rolling on the hot rolled plate after acid washing, and adopting a secondary rolling method, wherein the first cold rolling is warm cold rolling, the rolling temperature is 400-800 ℃, the reduction rate is 60%, then annealing at 950 ℃ for 20min and then carrying out quick cooling, and the second cold rolling is low in temperature, the rolling temperature is 300 ℃, the reduction rate is 78%, so as to obtain a cold-rolled thin strip with the thickness of 0.2 mm;

step 4, decarburization annealing:

cold rolled thin strip is processed at wet volume ratio of 25% N₂+75％H₂The decarburization annealing is carried out in the mixed atmosphere, the annealing temperature is 850 ℃, the annealing time is 5 min:

and 5, secondary recrystallization annealing:

the annealed sheet was annealed at constant temperature for different annealing temperatures and times under an inert reducing atmosphere to obtain a high magnetostriction coefficient Fe — Ga based thin strip, and the results of measuring the magnetostriction coefficient (3/2) λ s of the thin strip are shown in table 10.

TABLE 10 comparison of magnetostriction coefficients of Fe-Ga based thin strips with high magnetostriction coefficients prepared at different annealing temperatures, i.e., times

Serial number	Annealing temperature (. degree.C.)	Annealing time (min)	(3/2)λs(ppm)
				1	900	280	301
2	950	240	310
				3	1000	30	260
4	1000	600	308
				5	1100	15	275
6	1200	30	240
				Comparative experiment 7	1300	120	155

As can be seen from Table 10, the secondary recrystallization annealing was carried out by using a constant temperature system, and when the annealing temperature and time system were within the range of the present invention (No. 1-5), excellent magnetostriction properties could be obtained; when the annealing regime is out of the range of the present invention (comparative experiment 7), the magnetostrictive property is low.

Example 11

The Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: ga: 31%, C: 0.04%, Nb: 0.28%, Al: 0.025%, Sn: 0.06%, V: 0.1%, Mo: 0.2%, Tb: 0.2%, and the balance of Fe and other unavoidable impurities.

step 1, smelting:

step 2, hot rolling:

(1) heating the blank to 1100-1280 ℃ and preserving heat;

(2) hot rolling the heated and heat-preserved blank at the initial rolling temperature of 1150 ℃, and cooling to obtain a hot rolled plate with the thickness of 2.5 mm;

step 3, acid washing and cold rolling:

(1) pickling the hot rolled plate to remove oxide skin;

(2) carrying out cold rolling on the hot rolled plate after acid washing, and adopting a secondary rolling method, wherein the first cold rolling is warm cold rolling, the rolling temperature is 400-800 ℃, the reduction rate is 68%, then annealing at 1000 ℃ for 15min, then carrying out quick cooling, and the second cold rolling is low in temperature, the rolling temperature is 300 ℃, the reduction rate is 81%, so as to obtain a cold-rolled thin strip with the thickness of 0.15 mm;

step 4, decarburization annealing:

cold rolled thin strip is processed at wet volume ratio of 25% N₂+75％H₂The decarburization annealing is carried out in the mixed atmosphere, the annealing temperature is 830 ℃, the annealing time is 5 min:

and step 5, nitriding treatment:

thin strips, 15% NH in dry volume₃+20％N₂+65％H₂Nitriding treatment is carried out in mixed atmosphere, the nitriding temperature is 850 ℃, the nitriding time is 180s, and the nitriding amount is 400 ppm;

and 6, secondary recrystallization annealing:

the annealed sheet was kept at 1000 ℃ for 600min under the condition of inert reducing mixed atmosphere, and furnace-cooled, air-cooled and quenched, respectively, to obtain a Fe-Ga based ribbon with a high magnetostriction coefficient, and the results of measuring the magnetostriction coefficient (3/2). lambda.s thereof are shown in Table 11.

TABLE 11 comparison of magnetostriction coefficients of Fe-Ga based thin strips with high magnetostriction coefficients prepared by different cooling methods

Categories	Cooling method	(3/2)λs(ppm)
			1	Furnace cooling	330
2	Air cooling	345
			3	Quenching	370

It can be seen from Table 11 that after the secondary recrystallization annealing, higher hysteresis expansion and contraction performance can be obtained by the cooling method using quenching than furnace cooling and air cooling.

Example 12

The Fe-Ga-based thin strip with the high magnetostriction coefficient comprises the following components in percentage by weight: 22.3%, the other components are shown in table 12, and the balance is Fe and other unavoidable impurities.

step 1, ingot casting:

respectively smelting the thin strips according to the set components of the thin strips in the table 12 at 1440-1600 ℃, and then obtaining cast strips with the thickness of 2.8mm by using a thin strip continuous casting machine;

step 2, hot rolling:

(1) heating the casting belt to 1000-1280 ℃ and preserving heat;

(2) hot rolling the heated and insulated cast strip at the beginning temperature of 1025 ℃, and cooling to obtain a hot rolled plate with the thickness of 2.3 mm;

step 3, acid washing and cold rolling:

(1) pickling the hot rolled plate;

(2) and (3) cold rolling the hot rolled plate after acid washing, and obtaining a cold rolled thin strip with the thickness of 0.23mm by adopting a secondary rolling method, wherein:

a secondary rolling method: the first cold rolling is carried out at the rolling temperature of 400-800 ℃ and the reduction rate of 56%, then the steel is annealed at 900 ℃ for 5min and then rapidly cooled, and the second cold rolling is carried out at the lower temperature of 20 ℃ and the reduction rate of 77%;

step 4, decarburization annealing:

will be cold rolledThin strip in wet 25% N₂+75％H₂The decarburization annealing is carried out in the mixed atmosphere, the annealing temperature is 830 ℃, and the annealing time is 4 min;

and 5, secondary recrystallization annealing:

the results of heating the annealed sheet from 800 ℃ to 1200 ℃ at a rate of 20 ℃/h under an inert reducing atmosphere for 2 hours, quenching the heated sheet with water to obtain a high magnetostriction coefficient Fe-Ga based thin strip, and measuring the magnetostriction coefficient (3/2). lambda.s of the high magnetostriction coefficient Fe-Ga based thin strip of various components and contents in the case of using a strip-cast material are shown in Table 12

TABLE 12 comparison of magnetic elongation properties of Fe-Ga based thin strips with high magnetostriction coefficients of different compositions and contents

As can be seen from table 12, the inhibitor can be flexibly controlled by the thin-strip continuous casting method, so that the secondary recrystallization can be completed, and the hysteresis expansion and contraction performance is high.

On one hand, the existing preparation method of the Fe-Ga alloy with the high magnetostriction coefficient has complex process, such as directional solidification or cladding rolling; on the other hand, the control of the inhibitor is not matched with the secondary recrystallization process, so most of the inhibitor is introduced into surface segregation, on one hand, the advantage and the accuracy of selective growth of Goss are improved through surface energy induction, and on the other hand, the regression of the inhibitor on the surface layer is delayed through the formation of more precipitates of Nb and S on the surface layer, namely, the growth of crystal grains on the surface layer is further hindered. The introduction of surface segregation has the problems of high cost, high equipment precision requirement, difficult industrialization and the like.

The preparation method of the Fe-Ga-based thin strip with the high magnetostriction coefficient provided by the invention effectively solves the problems. Establishing a new inhibitor system design of low-temperature inherent inhibitor and nitriding, and controlling the heat treatment and rolling process to precipitate fine Cu₂S, Nb (C, N) and V (C, N) or composite precipitates thereof as main intrinsic inhibitors; when the inherent suppression force is insufficient, nitride is formed supplementarily by nitriding. In particular by continuous casting of thin stripThe advantage of rapid solidification realizes the control of restraining force flexibility, and eliminates the dependence on surface energy.

The coordination and collocation of the structure, the texture and the inhibitor are realized by reasonably controlling the components, the rolling process and the annealing process, and finally, the secondary recrystallization grains with perfect sharp eta (100 >// RD) texture are obtained, and the hysteresis expansion coefficient is improved.

At present, the market at home and abroad has very urgent need for Fe-Ga alloy with large magnetostriction coefficient and excellent mechanical property, the invention adopts plate blanks of die casting, plate blank continuous casting, sheet blank continuous casting and thin strip continuous casting, and can simply and efficiently carry out large-scale production by utilizing the traditional rolling and annealing process flows, and the hysteresis expansion and contraction performance is superior to the prior reports, thereby having good popularization and application prospects.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims

1. A preparation method of a Fe-Ga-based thin strip with a high magnetostriction coefficient is characterized by comprising the following steps:

step 1: smelting

step 2: hot rolling

(1) Heating the blank to 1000-1280 ℃ and preserving heat;

(2) hot rolling the heated and heat-preserved blank at the initial rolling temperature of 900-1250 ℃ and the final rolling temperature of 600-1050 ℃, and cooling to obtain a hot rolled plate with the thickness of 1-4 mm;

and step 3: pickling and cold rolling

(1) Pickling the hot rolled plate to remove oxide skin;

(2) and (3) cold rolling the hot rolled plate after acid washing to obtain a cold rolled thin strip with the thickness of 0.10-1.0 mm, wherein the cold rolling comprises the following two rolling methods, and any one of the rolling methods can be adopted for cold rolling:

a secondary rolling method: the first cold rolling is carried out at room temperature to 800 ℃, the reduction rate is 30-95%, then the steel is annealed at 800-1100 ℃ for 5-120 min and then rapidly cooled, and the second cold rolling is carried out at a lower temperature, the rolling temperature is room temperature to 600 ℃, and the reduction rate is 50-92%;

and 4, step 4: decarburization annealing

Cold rolling thin strip in wet N₂+H₂In a mixed atmosphere, decarburization annealing is carried out, the annealing temperature is 800-1000 ℃, the annealing time is 2-30 min, N₂The volume ratio of the water-soluble organic acid is 20-75%;

and 5: secondary recrystallization annealing

Carrying out secondary recrystallization annealing treatment on the annealing plate obtained by decarburization annealing under the condition of inert atmosphere or inert reducing mixed atmosphere to obtain a Fe-Ga-based thin strip with high magnetostriction coefficient, wherein the secondary recrystallization annealing treatment comprises the following two modes, and can be carried out in any mode:

the first mode is as follows: heating the annealing plate from 600-900 ℃ to 1000-1200 ℃ and preserving heat for 0.5-10 h, wherein continuous heating or multi-section annealing with intermediate heat preservation is adopted in the heating process;

and a second mode: annealing the annealed plate at 900-1200 ℃ for 15-600 min at constant temperature;

the prepared Fe-Ga-based thin strip with high magnetostriction coefficient comprises the following components in percentage by weight: ga: 15-32%, C: 0.001-0.12%, Al: 0.005-0.08%, N: 0.006-0.02%, Nb: 0.03-0.75%, and the balance of Fe and other inevitable impurities.

2. A preparation method of a Fe-Ga-based thin strip with a high magnetostriction coefficient is characterized by comprising the following steps:

step 1: smelting

step 2: hot rolling

(1) Heating the blank to 1000-1280 ℃ and preserving heat;

(2) hot rolling the heated and heat-preserved plate blank at the initial rolling temperature of 900-1250 ℃ and the final rolling temperature of 600-1050 ℃, and cooling to obtain a hot rolled plate with the thickness of 1-4 mm;

and step 3: pickling and cold rolling

(1) Pickling the hot rolled plate to remove oxide skin;

and 4, step 4: decarburization annealing

Cold rolling thin strip into wet N₂+H₂In a mixed atmosphere, decarburization annealing is carried out, the annealing temperature is 800-1000 ℃, the annealing time is 2-30 min, N₂The volume ratio of the water-soluble organic acid is 20-75%;

and 5: nitriding treatment

Subjecting the thin strip to dry NH₃+N₂+H₂Nitriding in a mixed atmosphere, H₂50-80% of NH₃The nitriding temperature is 600-1050 ℃, the nitriding time is 10-500 s, and the nitriding amount is 30-800 ppm;

step 6: secondary recrystallization annealing

And (3) performing secondary recrystallization annealing treatment on the annealed plate subjected to nitriding treatment under the condition of inert atmosphere or inert reducing mixed atmosphere to obtain the Fe-Ga-based thin strip with high magnetostriction coefficient, wherein the secondary recrystallization annealing treatment comprises the following two modes, and can be performed in any one mode:

3. The method for manufacturing a Fe-Ga based thin strip with a high magnetostriction coefficient according to claim 1 or 2, wherein the post-smelting casting is performed by any one of die casting, slab casting, and strip casting.

4. The method for producing a Fe-Ga based thin strip with a high magnetostriction coefficient according to claim 1 or 2, wherein the pickling is carried out after a hot rolled sheet is subjected to a normalizing annealing treatment, wherein the normalizing annealing temperature is 700 to 1100 ℃, the normalizing annealing time is 2 to 120min, and the strip is rapidly cooled after the normalizing treatment.

5. The method for producing a Fe-Ga-based thin ribbon with a high magnetostriction coefficient according to claim 1 or 2, wherein the secondary recrystallization annealing treatment is performed under an inert atmosphere or an inert reducing mixed atmosphere, and the inert atmosphere is a nitrogen atmosphere or an argon atmosphere; the inert reducing mixed atmosphere refers to the mixed atmosphere of inert gas and hydrogen.

6. The method of claim 1 or 2, wherein the secondary recrystallization annealing is performed by cooling by any one of furnace cooling, air cooling, and quenching.

7. The method of claim 2, wherein the nitriding is performed before the decarburization annealing, after the decarburization annealing, or simultaneously with the decarburization annealing.

8. The method for producing a Fe-Ga-based thin strip with a high magnetostriction coefficient according to claim 1 or 2, wherein the Fe-Ga-based thin strip with a high magnetostriction coefficient further comprises the following components in percentage by weight: cu: less than or equal to 0.5 percent, S: 0.008-0.035%, Mn: 0.01 to 0.3 percent.

9. The method for producing a Fe-Ga-based thin strip with a high magnetostriction coefficient according to claim 1 or 2, wherein the Fe-Ga-based thin strip with a high magnetostriction coefficient further comprises the following components in percentage by weight: sn: 0.02 to 0.1%, Sb: 0.01-0.03%, V: 0.01 to 0.1%, Mo: 0.01-3.0%, Tb: 0.05-0.6% or B: 0.005-0.05% of one or more.