IRON-BASED AMORPHOUS ALLOY HAVING LOW STRESS SENSITIVITY, AND PREPARATION METHOD THEREFOR

Abstract

An iron-based amorphous alloy. The iron-based amorphous alloy comprises components FeaBbSic, a, b and c respectively indicating atomic percentage contents, 79.5≤a≤82.5, 11.0≤b≤13.5, 6.5≤c≤8.5, and a+b+c=100. An iron-based amorphous alloy strip is obtained by means of a rapid quenching method in which a single roller is used. Because the iron-based amorphous alloy has higher saturated magnetic induction density, a higher amorphous formation capability and lower stress-resistance sensitivity, the iron-based amorphous alloy can be used as an iron core material for preparing a power transformer, a power generator and an engine; in addition, due to the low stress sensitivity of the iron-based amorphous alloy, the sudden short-circuit resistance capability of an amorphous transformer can be improved when the power transformer is prepared.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Chinese Patent Application No. 201710447487.1, filed on Jun. 14, 2017, and titled with “IRON-BASED AMORPHOUS ALLOY HAVING LOW STRESS SENSITIVITY, AND PREPARATION METHOD THEREFOR”, and the disclosures of which are hereby incorporated by reference.

FIELD

The present disclosure relates to the field of iron-based amorphous alloy technology, especially to an iron-based amorphous alloy having low stress sensibility, and a method for preparing the same.

BACKGROUND

Due to its low iron loss, high saturation magnetic flux density, high permeability, and other advantages, Fe-based amorphous alloy strips such as Fe-Si-B amorphous alloys are widely used as iron cores for power transformers and high-frequency transformers. Based on the above characteristics, iron-based amorphous materials have taken the lead in the transformer field for a long period of time ever since they were invented.

With the continuous renewal of silicon steel materials, the advantages of amorphous materials are relatively weakened. For example, amorphous materials have significantly low saturated magnetic density, low magnetic induction, poor anti-stress sensibility and so on. In recent years, a lot of works have been done to improve the saturation magnetic induction and reduce the loss of amorphous materials, but there is no noticeable result for the study of the anti-stress sensibility of amorphous materials. The stress removal is the fundamental guarantee of the low loss characteristics of amorphous materials. In addition, as a main material of the transformer magnetic circuit, the thickness of the amorphous alloy strip is 20-30 μm. Because it is hard and brittle and difficult to be cut, the cross section of iron core of amorphous alloy transformer is rectangular, so that the corresponding high and low voltage windings are rectangular. Rectangular windings have relatively poor ability to withstand short circuits with respect to the circular windings, so it is necessary to improve the ability of the amorphous alloy transformers to withstand short-circuits.

The stress of the amorphous transformer core is mainly composed of two parts of stress, one is the internal stress generated during the preparation process of amorphous material, i.e., the internal stress generated during quenching of the amorphous material, the other is an unavoidable assembly external stress due to the characteristics of the iron core during the manufacturing process of the iron core. A large number of researches for reduce the stress mainly focus on the annealing process and optimizing the transformer core structure.

The internal stress generated during quenching of amorphous materials is mainly related to the formation of amorphous materials. Rapid cooling is a necessary condition for the formation of amorphous materials. When a high-temperature molten material is poured onto a cooling substrate and cooled at a speed of 10⁶° C./s, an amorphous strip with a short-range order and long-range disorder structure is formed. This short-range disorder liquid is “frozen,” and internal stresses are generated in these “frozen” structures. The internal stress of the amorphous material can be effectively removed through the annealing process, and the amorphous industry has done a lot of works to remove the internal stress through the annealing process. When the internal stress generated during quenching is removed by annealing, thermal stress is induced by the large difference of the temperature in core at the same time, i.e., the internal stress cannot be completely removed.

The assembly external stress is mainly caused by the process of producing the iron core from the amorphous strip during core assembly and the external stress caused by the structural characteristics of the core itself. This kind of stress is unavoidable and there is little study on the removal of it, which is mainly through the optimization of the iron core structure of the transformer and the specification of the operation. Amorphous alloy transformer windings have a rectangular structure, and the electric power received by them is far less uniform than that of a circular winding of ordinary transformers. It is easier to be deformed when subjected to sudden short circuit electric power. Since the iron core material of amorphous alloy transformer is very sensitive to mechanical stress, both tensile and bending stress will affect its performance, which should be fully considered in the structure design to reduce the force on the iron core. Generally, special fastening designs are used, and the amorphous alloy transformer body is an axial bearing structure. The stresses on the amorphous alloy core and the rectangular windings do not interfere with each other. The rectangular windings are pressed by the upper and lower clamps and the pressure plate to form a compression structure by itself. Therefore, it suffers more from the short-circuit electric power in the axial and radial directions of the rectangular winding than the circular winding. In order to reduce the difficulty in the assembly and design of the transformer, it is important to reduce the stress sensibility of the amorphous alloy.

For example, Japanese Patent No. JPS63-45318 discloses a method for improving the annealing process, mainly by reducing the temperature difference in the iron core. In this method, a heat insulating material is installed on the inner and outer circumferential surfaces of the iron core to minimize the temperature difference in the iron core during cooling, so as to improve the properties of thin strip itself and improve the weight and bulk of the iron core. Iron core is put into a heat treatment furnace and heated, and temperature variation occurs in various parts of the iron core. Annealing and removing stress in this method does not cause crystallization due to excessive core temperature in the furnace or does not cause the phenomenon of incomplete stress removal due to low temperature. However, the specific procedures of this method are not described in the disclosure, and the process of annealing the iron core and the annealing cost are increased, so that it is not practical in actual annealing process.

The Chinese Patent No. CN1281777 C discloses that by adding a specific range of P in the restricted ranges of Fe, Si, B, and C, it is found that under the situation of uneven temperature in various parts of the iron core during annealing, iron core annealing at lower temperatures can also exhibit excellent soft magnetic properties. The inventors only considered the effect of P on reducing the temperature unevenness of the amorphous iron core, and not the problems of oxidation and surface crystallization of the phosphorus-containing amorphous strip. The element P has extremely poor oxidation resistance. When annealing in an aerobic environment, the performance and the apparent quality of iron core will easily become worse due to oxidation. For example, when phosphorus-containing amorphous materials are annealed under the conditions for Fe, Si, B, and C annealing, the surfaces of the strip become blue due to oxidation, and the performance deteriorates. This has very strict requirements for the oxygen content of the annealing atmosphere. At present, there is no preparation of ferrophosphorus of the amorphous strip, and the introduction of phosphorus and iron will generate unavoidable impurities, and the crystallization on the strip surface will easily occur. In summary, the above method avoids the defects of large temperature difference inside the iron core, but introduces problems such as oxidation during annealing and of the amorphous strip and crystallization on the strip surface.

The U.S. Patent Publication No. US20160172087 discloses the study of the stress release based on different components, pointing out the effect of B and C on the stress release, and illustrating the amount of stress released after the strip annealing through an experimental model. However, the inventor only explained the degree of stress release from the point of internal stress removing and stress release after annealing from a single strip, without considering the final soft magnetic properties of the material and the performance deterioration of the transformer core due to the assembly stress.

In view of the above, although the embodiments of the above disclosures have optimized the annealing process or the assembly process of the amorphous transformer iron core and the stress of the amorphous strip can be removed to a great extent. However, the feasibility of strip preparation and implementation of these optimizations are not specifically considered, and a more comprehensive understanding of the stress relieving (stress avoidance) of amorphous strips is missing. The results are relatively one-sided.

SUMMARY

The technical problem solved by the present disclosure is to provide an iron-based amorphous alloy strip, and the iron-based amorphous alloy strip of the present disclosure has relatively low stress sensibility.

In view of this, the present disclosure provides an iron-based amorphous alloy represented by formula (I):

Fe_aB_bSi_c   (I);

wherein a, b and c are each independently atomic percentages of corresponding components; 79.5≤a≤82.5, 11.0≤b≤13.5, 6.5≤c≤8.5, and a+b+c=100.

Preferably, the saturation magnetic induction of the iron-based amorphous alloy is ≥1.60 T.

Preferably, the atomic percentage of Fe is 80.0≤a≤81.5.

Preferably, the atomic percentage of B is 11.0≤b≤12.5.

Preferably, the atomic percentage of Si is 7.0≤c≤8.0.

Preferably, in the iron-based amorphous alloy, a=80.0, 12.0≤b≤13.0, 7.0≤c≤8.0.

Preferably, in the iron-based amorphous alloy, a=80.5, 11.5≤b≤12.5, 7.0≤c≤8.0.

Preferably, in the iron-based amorphous alloy, 81.0≤a≤81.5, 11.0≤b≤13.0, 7.0≤c≤8.0.

The present disclosure further provides a method for preparing the iron-based amorphous alloy strip represented by formula (I), comprising:

preparing raw materials according to the atomic percentages indicated in formula (I); smelting the raw materials; heating and insulating the molten liquid after smelting; performing single roller rapid quenching to obtain an iron-based amorphous alloy strip;

Fe_aB_bSi_c   (I);

wherein a, b and c are each independently atomic percentages of corresponding components; 79.5≤a≤82.5, 11.0≤b≤13.5, 6.5≤c≤8.5, and a+b+c=100.

Preferably, after the single roller rapid quenching, the iron-based amorphous alloy is subjected to heat treatment.

Preferably, prior to the heat treatment, the iron-based amorphous alloy is winded into a sample ring with an inside diameter of 50.5 mm and an outside diameter from 53.5 to 54 mm.

After heat treatment, the allowable gauge factor of the sample ring loss is 10.0%, and allowable gauge factor of the excitation power is 6%.

Preferably, coercive force of the heat treated iron-based amorphous alloy strip is ≤3.5 A/m; under a condition of 50 Hz and 1.35 T, excitation power of the heat treated iron-based amorphous alloy strip is ≤0.1450 VA/kg, and core loss is ≤0.1100 W/kg; and under a condition of 50 Hz and 1.40 T, excitation power of the heat treated iron-based amorphous alloy strip is ≤0.1700 VA/kg, and core loss is ≤0.1500 W/kg.

Preferably, the iron-based amorphous alloy strip is in completely amorphous phase with a limit thickness of at least 75 nm and a shearing limit strip thickness of at least 29 nm.

The present disclosure provides an iron-based amorphous alloy strip, which has an atomic composition represented by formula Fe_aB_bSi_c, wherein a, b and c are each independently atomic percentages of corresponding components; 79.5≤a≤82.5, 11.0≤b≤13.5, 6.5≤c≤8.5, and a+b+c=100; Fe in the iron-based amorphous alloy provided by the present disclosure ensures obtaining stable amorphous iron-based alloys having lower preparation requirements and higher yield; Si element is conducive to the stable formation of amorphous materials; and B is the element that contributes most to the amorphousness of the alloy. Thus, by adjusting the contents of Fe, Si, and B, the present disclosure prepares an iron-based amorphous alloy having high saturation magnetic induction strength, high ductility and low stress sensibility, which makes the transformer assembled by the iron core made from the alloy having strong sudden short circuit resistance.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of the simulation experiment equipment for the iron-based amorphous alloy sample ring prepared in the present disclosure under condition of no stress.

FIG. 2 is a schematic diagram of the simulation experiment equipment for the iron-based amorphous alloy sample ring prepared in the present disclosure under condition of stress.

DETAILED DESCRIPTION

In order to further understand the present disclosure, the preferred embodiment of the present disclosure is described hereinafter in conjunction with the examples of the present disclosure. It is to be understood that the description is merely illustrating the characters and advantages of the present disclosure, and is not intended to limit the claims of the present disclosure.

Either internal stress or external stress is inevitable. Stress still exists after optimizing the annealing process, optimizing the iron-core structure of transformer and standardizing the operation. A main object of the present disclosure is to establish a range of amorphous composition having low stress sensibility through adjusting components and evaluating the stress (internal stress and external stress) of strip with different components, so as to effectively show excellent soft magnetic properties of amorphous products, and produce an amorphous transformer that has a relatively good ability of withstanding sudden short-circuit. Thus, the present disclosure discloses an iron-based amorphous alloy represented by formula (I):

Fe_aB_bSi_c   (I);

wherein a, b and c are each independently atomic percentages of corresponding components; 79.5≤a≤82.5, 11.0≤b≤13.5, 6.5≤c≤8.5, and a+b+c=100.

The iron-based amorphous alloy provided by the present disclosure comprises Fe, Si and B, and through adjusting the content of the above elements to give alloy a relatively good glass forming ability, saturation magnetic induction and soft magnetic property. Furthermore, after heat treatment, the strip made of the iron-based amorphous alloy provided by the present disclosure has relatively low anti-stress sensibility.

In the iron-based amorphous alloy, Fe is the base element, and the content of it is 79.5≤a≤82.5 by atomic percentage. If the atomic percentage of Fe is unduly low, the saturation magnetic induction of the iron-based amorphous alloy will be unduly low, so that it cannot improve the defect of low magnetic flux density of the amorphous and cannot obtain enough magnetic flux density and an iron core with compact structure. When the content is unduly high, the thermal stability of iron-based amorphous alloy and the formability of strip are decreased, making it hard to smooth operation of the strip and obtain a good magnetic product. In the embodiments, the atomic percentage of Fe is 79.5≤a≤81.5, more specifically, the atomic percentage of Fe is 80.0≤a≤81.5.

The atomic percentage of Si is 6.5≤c≤8.5. When the content is unduly low, the formability of iron-based amorphous alloy strip and the thermal stability of amorphous alloy strip are decreased, making it hard to form a stable amorphous material. When the content is unduly high, the brittleness of the iron-based amorphous alloy becomes high, and the ductility of the annealed strip becomes worse. In the embodiments, the content of Si is 7.0≤c≤8.0.

The atomic percentage of B is 11.0≤b≤13.5. When the content of B is unduly low, it is hard to form a stable amorphous material. When the content is unduly high, the ability of forming amorphous state does not further improve, i.e., the content of B in the above range gives the iron.-based amorphous alloy of the present disclosure excellent soft magnetic property. In embodiments, the content of B is 11.0≤b≤13.0, more specifically, the content of B is 11.0≤b≤12.5.

In the present disclosure, a preferably composition of the iron-based amorphous alloy is: a=80.0, 12.0≤b≤13.0, and 7.0≤c≤8.0; or a=80.5, 11.5≤b≤12.5, and 7.0≤c≤8.0; or 81.0≤a≤81.5, 11.0≤b≤13.0, and 7.0≤c≤8.0.

The iron-based amorphous alloy composition and contents provided by the present disclosure is a reasonable combination of improving magnetic induction and improving glass forming ability, forming an iron-based amorphous alloy with high saturation magnetic induction. Further, on the base of high saturation magnetic induction, the iron-based amorphous alloy of the present disclosure also has low stress sensibility. The reason why the iron-based amorphous alloy provided by the present disclosure has high saturation magnetic induction and low stress sensibility is due to the adjustment of the composition and content of the iron-based amorphous alloy.

The present disclosure further provides a method for preparing the iron-based amorphous alloy strip represented by formula (I), comprising:

preparing raw materials according to the atomic percentage of formula (I); smelting the raw materials; heating and insulating the molten liquid after smelting; performing single roller rapid quenching to obtain an iron-based amorphous alloy strip;

Fe_aB_bSi_c   (I);

wherein a, b and c are each independently atomic percentages of corresponding components; 79.5≤a≤82.5, 11.0≤b≤13.5, 6.5≤c≤8.5, and a+b+c=100.

In the process of preparing the iron-based amorphous alloy strip, conventional methods in the art are used to prepare the iron-based amorphous alloy strip with the specific composition of the present disclosure. The preparing and smelting processes above are well known to one of ordinary skill in the art, which would not be descripted in details in the present disclosure. In the smelting process, the metal raw materials are smelted in a medium frequency furnace, and the smelting temperature is from 1300 to 1500° C., and the duration is from 80 to 120 minutes. After smelting, in the present disclosure, the molten material is heated and insulated, and subjected to single roller rapid quenching, so as to obtain the iron-based amorphous alloy strip. The heating temperature is preferably from 1350 to 1470° C., and the insulating duration is preferably from 20 to 50 minutes. After single roller rapid quenching, an iron-based amorphous alloy strip is obtained in completely amorphous state, and limit thickness of the formed amorphous is at least 75 μm, and toughness of the strip is relatively good, which will not crack after 180 degree folding.

For the present disclosure, the shearable limit thickness of the strip is at least 29 μm, so that the present product has pretty large production margin in industrial production and requirement of the cooling equipment in the industrial process is decreased.

In the present disclosure, after the raw iron-based amorphous alloy strip is prepared, it is subjected to heat treatment for ease of application. The iron-based amorphous alloy provided by the present disclosure is capable to be treated in a relatively wide annealing range, and the iron-based amorphous alloy strip obtained has relatively low excitation power and loss. In the present disclosure, the heat treatment temperature is from 325 to 395° C.; and in embodiments, the heat treatment temperature is from 335 to 385° C.

According to the present disclosure, prior to the heat treatment, the obtained iron-based amorphous alloy is preferably winded into a sample ring with an inside diameter of 50.5 mm and an outside diameter of from 53.5 to 54 mm, and then the above sample ring is subjected to heat treatment.

Loss and deterioration of excitation power of the heat treated sample ring under conditions of stress are detected through simulation experiments, so as to illustrate transition of the properties of iron-based amorphous alloy strip under condition of stress. If the loss and the deterioration coefficient of excitation power of the iron-based amorphous alloy strip still lay in an acceptable range under conditions with a relatively large gauge factor, the iron-based amorphous alloy strip has relatively low stress sensibility. If the loss and the deterioration coefficient of excitation power of the iron-based amorphous alloy strip are unacceptable when the gauge factor is relatively small, the stress sensibility of the iron-based amorphous alloy strip is relatively bad. Through the simulation experiment of the present disclosure, the experiment results show that the iron-based amorphous alloy strip has relatively low stress sensibility.

In the present disclosure, by adjusting the components and content of the components, i.e., components and content of the components cooperate with each other, the magnetic property of the iron-based amorphous alloy is improved and the stress sensibility of the iron-based amorphous alloy strip is decreased at the same time.

In order to understand the present disclosure better, the iron-based amorphous alloy will be illustrated in details in conjunction with embodiments hereinafter, and the protection scope of the present disclosure is not limited by the following embodiments.

EXAMPLE

1) Preparation of the Iron-Based Amorphous Alloy Strip

According to the alloy components represented by formula Fe_aB_bSi_c, industrial pure iron, silicon and boron were used to prepare the alloys shown in Table 1. Except for the main elements, there are unavoidable impurity elements in the alloys, such as C, Mn, S, and so on. The materials with different components were successively added to a medium frequency furnace of a furnace volume of 100 kg in the order of boron iron, silicon and pure iron for remelting (the smelting temperature was from 1300 to 1500° C., and the duration was from 80 to 120 minutes). After holding, the molten steel was casted to the spraying ladle for producing an amorphous strip with a width of 20 mm by single roller planar flow casting. In the strip producing process, alloy strips with different thicknesses were produced by adjusting parameters such as roller speed, liquid level and so on (in the strip producing process, the roller speed was from 1000 to 1400 r/min, and the linear speed of the strip producing is from 20 to 30 m/s, and the liquid level was from 200 mm to 300 mm).

2) Test of Glass Forming Ability and Saturation Magnetic Induction of Iron-Based Amorphous Alloy Strip

XRD was used to test the free face of strips with different components until the strip thickness was in the amorphous state. Table 1 showed the limit thicknesses of each strip with different amorphous alloy compositions. The saturation magnetization induction of the amorphous alloy strips were measured with VSM. The alloy compositions were comprehensively evaluated by the glass forming ability and saturation magnetic induction of the strips. According to the number of brittle points, maximum shearing thickness of the strip was evaluated. The method for evaluating brittle point is: taking the strip which has a length equal to the perimeter of the crystallizer and shearing the strip along the longitudinal direction. When the number of the brittle point was not more than 2, the strip was considered to be shearable, and when the number of the brittle point was 2, the length was regarded as the shearable limit thickness of the alloy strip.

TABLE 1
iron-based amorphous alloy with different
compositions and their properties
	Limit Thickness	Shearable
	of the Obtained	limit
	Composition	Amorphous Strip	thickness	Bs
Group	Fe	Si	B	(μm)	(μm)	(T)
Example 1	80.0	8.0	12.0	80	30	1.60
Example 2	80.0	7.5	12.5	82	29	1.60
Example 3	80.0	7.0	13.0	80	30	1.61
Example 4	80.5	8.0	11.5	80	30	1.61
Example 5	80.5	7.5	12.0	80	33	1.62
Example 6	80.5	7.0	12.5	80	33	1.62
Example 7	81.0	8.0	11.0	75	32	1.62
Example 8	81.0	7.5	11.5	75	32	1.62
Example 9	81.0	7.0	12.0	75	33	1.62
Example 10	81	6.5	12.5	75	33	1.63
Example 11	81.5	7.0	11.5	65	38	1.62
Comparative	78.0	9.0	13.0	85	26	1.55
Example 1
Comparative	79.5	9.5	11.0	80	27	1.56
Example 2
Comparative	79.0	9.0	12.0	80	27	1.56
Example 3
Comparative	80.0	9.0	11.0	75	26	1.57
Example 4
Comparative	80.0	6.0	14.0	78	30	1.61
Example 5
Comparative	80.5	9.0	10.5	75	25	1.58
Example 6
Comparative	80.5	6.0	13.5	80	32	1.63
Example 7
Comparative	82.0	6.0	12.0	50	36	1.63
Example 8
Comparative	83.0	6.5	10.5	45	37	1.64
Example 9

Table 1 showed the limit thickness of the amorphous strips, toughness limit thickness of strip producing and saturation magnetic induction of alloys with different compositions. The amorphous strip limit thickness and the toughness limit thickness of strip producing are the tests for strip producing technology. The thicker the strip thickness was, the more relax the requirement for the strip producing equipment was.

Under the same strip producing condition, the thicker the amorphous strip limit thickness of the alloy, the higher the degree of non-crystallinity of strip was. Although comparative examples 1 to 4 have a relatively high amorphous strip limit thickness, the maximum shearing thickness was below 27 μm. This not only puts more stringent requirements on the cooling intention of the strip producing equipment, but also influences the assembly efficiency of iron core. At the same time, it also carried foreshadows of breaking in assembly and operation process of transformer, leading to an increasing of potential safety hazard in operation of transformer. In addition, the saturation magnetic induction was less than 1.57 T, giving less flexibility to the design of amorphous transformers, and could not meet the design trend of high flux density of transformers. Comparing the comparative example 6 with the examples 4 to 6, it could be concluded that when the content of Fe was the same, the higher the content of Si was, the thinner the shearing thickness was.

In the comparative examples 8 to 9, the relatively high saturation magnetic induction of the amorphous alloy was expected for the design of transformer. The maximum shearing thickness was between 36 and 38 μm, which was absolutely superior in terms of efficiency in core molding. However, its amorphous forming ability was obviously insufficient based on the limit thickness of the amorphous strip, so it did not meet the requirements for smooth operation of producing strip and it also affected its excitation power and loss.

It could be concluded from Table 1 that from the comprehensive consideration of smooth operation of strip producing and transformer design, the alloy compositions of examples 1 to 11 have a smooth operation performance and a wide range of transformer design.

Strips with a thickness of 26 to 28 μm and a width of 30 mm in Table 1 were wound into sample rings with an inner diameter of 50.5 mm and an outer diameter of 53.5 to 54 mm. The sample rings were subjected to stress relief annealing using a box type annealing furnace.

Annealing was carried out under the protection of argon-with a temperature from 325 to 395° C. at an interval of 10° C. and 1 hour insulation. A magnetic field along the direction of strip preparing was added during the heat treatment process with a magnetic field strength of 1200 A/m. The silicon steel tester was used to test the excitation magnetic and loss of the strip after heat treatment. The test conditions were 1.35 T/50 Hz and 1.40 T/50 Hz respectively. The test results of the characteristic tests were shown in Table 2.

TABLE 2
Property data of the samples and the comparative
samples after the heat treatment
	1.35 T/50 Hz	1.4 T/50 Hz
	Composition	Pe	P	Pe	P
Group	Fe	Si	B	(VA/kg)	(W/kg)	(VA/kg)	(W/kg)
Example 1	80.0	8.0	12.0	0.130	0.099	0.170	0.130
Example 2	80.0	7.5	12.5	0.135	0.098	0.165	0.133
Example 3	80.0	7.0	13.0	0.128	0.103	0.168	0.140
Example 4	80.5	8.0	11.5	0.132	0.102	0.165	0.138
Example 5	80.5	7.5	12.0	0.125	0.085	0.145	0.115
Example 6	80.5	7.0	12.5	0.120	0.090	0.150	0.118
Example 7	81.0	8.0	11.0	0.140	0.108	0.158	0.135
Example 8	81.0	7.5	11.5	0.138	0.100	0.162	0.130
Example 9	81.0	7.0	12.0	0.133	0.105	0.165	0.139
Example 10	81	6.5	12.5	0.135	0.102	0.160	0.138
Example 11	81.5	7.0	11.5	0.140	0.106	0.165	0.145
Comparative	78.0	9.0	13.0	0.156	0.138	0.230	0.165
Example 1
Comparative	79.5	9.5	11.0	0.141	0.123	0.223	0.167
Example 2
Comparative	79.0	9.0	12.0	0.145	0.121	0.215	0.154
Example 3
Comparative	80.0	9.0	11.0	0.136	0.104	0.187	0.150
Example 4
Comparative	80.0	6.0	14.0	0.146	0.110	0.170	0.150
Example 5
Comparative	80.5	9.0	10.5	0.142	0.125	0.225	0.155
Example 6
Comparative	80.5	6.0	13.5	0.130	0.093	0.154	0.120
Example 7
Comparative	82.0	6.0	12.0	0.169	0.148	0.189	0.165
Example 8
Comparative	83.0	6.5	10.5	0.167	0.145	0.187	0.170
Example 9

It could be concluded form the Table 2 that under the condition of 1.35 T/50 Hz, the loss values of comparative examples 1 to 3 and comparative examples 8 to 9 were relatively high, and the performance was above 0.12 W/kg; and under the condition of 1.4 T/50 Hz, the excitation and loss of comparative examples 1 to 4 and 6 were significantly higher than that of 1.35 T/50 Hz, and were significantly higher than other samples at 1.4 T/50 Hz, and this was mainly related to the low saturated magnetic flux density of the above samples. The excitation magnetic and loss of the amorphous material increase with the increase of the magnetic density. Especially, the performance of excitation power was particularly prominent. Comparing with materials with low saturation magnetic induction, amorphous materials with high saturation magnetic induction allow a greater working magnetic density, i.e., showing relatively low excitation power and losses at magnetic density of 1.4 T. Normally speaking, the comparative examples 8 to 9 show a better performance at 1.4 T test. However, due to the relative large values of them at 1.35 T, the loss and excitation magnetic at 1.4 T increased, resulting in a relatively large value at 1.4 T.

Examples 1 to 11 exhibited excellent soft magnetic properties at 1.35 T/50 Hz and 1.40 T/50 Hz; loss at 1.35 T/50 Hz was below 0.11 W/kg, and loss at 1.40 T/50 Hz was below 0.15 W/kg.

3) Test of Stress Sensibility

The study above mentioned that amorphous materials have relatively low unavoidable loss values, and the performances of amorphous materials were deteriorated by external stress after they were assembled into an iron core. In the present study, a stress model of amorphous sample ring was established to characterize the performance deterioration of amorphous alloys with different compositions after stress deformation, and simulated the performance changes caused by stress when amorphous strip assembled into transformer cores.

Sample processing: the amorphous strips listed in Table 3 were selected, wound into a sample ring with an inner diameter of 50.5 mm and an outer diameter of 53.5 to 54 mm, and subjected to stress removing and annealing with a box annealing furnace under the protection of argon. Sample rings prepared with different compositions were chosen, and subjected to heat treatment according to the above requirements. The thermal insulation temperature of the heat treatment was from 325 to 395° C. with 5° C. as a gradient for the heat treatment, the insulation duration was from 60 to 120 min, and the magnetic field strength was from 800 to 1400 A/m. The optimal heat treatment performances of each component in the above heat treatment process were chosen to test the performance deterioration of the strip after stress.

The application of stress was considered by calculating the retraction distance of the circular strip. The feed amount of the sample ring was calculated according to the deformation coefficient formula. As shown in FIG. 1, FIG. 1 was a schematic diagram of the simulation experiment equipment of the sample ring under condition of no stress, and FIG. 2 was a schematic diagram of the simulation experiment equipment of the sample ring under condition of stress. When the sample ring was under stress, the A plate was fixed, and the feeding amount of the sample ring was given with the action of pushing plate B. The sample ring was deformed by the stress, and the pushing plate B was fixed. The loss P₁ and excitation power Pe₁ of the material under deformation conditions were measured, and the performance of the sample at 1.35 T/50 Hz was tested with a silicon steel tester.

The initial sample ring (without deformation) has an inner diameter of D₀ and performance values of P₀ and Pe₀ respectively. After deformation, the inner diameter was D₁, and the performance values were P₁ and Pe₁ respectively. The gauge factor=(D₁−D₀)*100%/D₀. The loss deterioration coefficient=(P₁−P₀)*100%/P₀. The excitation power deterioration coefficient=(Pe₁−Pe₀)/Pe₀.

Comprehensively considering the difference of the selected performances and the permissible degree of deterioration of the performance after deformation, this experiment stipulated that the performance deterioration within 50% was an acceptable range, and the sample ring deformation corresponding to the performance value was the maximum allowable deformation coefficient value of the corresponding component material.

It could be concluded from Table 3 that due to the difference in the composition itself, the best performances were slightly different. The performance value of the Comparative Example 9 was relatively large, and other performance values were basically at the same level. The heat treatment temperature ranged from 345 to 385° C. due to the difference in composition. In the stress experiment, the samples with different compositions having best performance after annealing were selected for stress sensibility experiments.

TABLE 3
Performance data of samples with different
compositions after optimum heat treatment
	1.35 T/50 Hz
	Best Thermal
	Composition	Treatment	P	Pe
Group	Fe	Si	B	Temperature	(W/kg)	(VA/kg)
Comparative	79	9	12	385	0.121	0.145
Example 3
Example 4	80.5	8	11.5	355	0.106	0.131
Example 5	80.5	7.5	12	365	0.085	0.125
Example 6	80.5	7	12.5	365	0.09	0.12
Example 12	79.5	8.5	12	385	0.103	0.137
Example 13	82.5	6.5	11	345	0.110	0.145
Comparative	80.5	6	13.5	355	0.093	0.13
Example 7
Comparative	83	6.5	10.5	345	0.145	0.167
Example 9

TABLE 4
Loss values and deterioration coefficient
under different gauge factors
	P(W/kg)
	Gauge Factor
Category	0%	2.0%	4.0%	6.0%	8.0%	10.0%
Comparative	0.121	0.134	0.144	0.15	0.178	0.235
Example 3
Example 4	0.106	0.109	0.114	0.118	0.125	0.156
Example 5	0.085	0.089	0.093	0.098	0.103	0.121
Example 6	0.09	0.093	0.098	0.102	0.107	0.123
Example 12	0.103	0.109	0.113	0.121	0.137	0.151
Example 13	0.110	0.116	0.125	0.138	0.148	0.16
Comparative	0.093	0.105	0.109	0.115	0.128	0.165
Example 7
Comparative	0.145	0.165	0.173	0.186	0.198	0.258
Example 9

TABLE 4
Loss values and deterioration coefficient under
different gauge factors (Continued Table)
	Deterioration Coefficient of P	Maximum
	Gauge Factor	Gauge
Category	2.0%	4.0%	6.0%	8.0%	10.0%	Factor
Comparative	10.7%	19.0%	24.0%	47.1%	94.2%	8.0%
Example 3
Example 4	2.8%	7.5%	11.3%	17.9%	47.2%	10.0%
Example 5	4.7%	9.4%	15.3%	21.2%	42.4%	10.0%
Example 6	3.3%	8.9%	13.3%	18.9%	36.7%	10.0%
Example 12	5.8%	9.7%	17.5%	33.0%	46.6%	10.0%
Example 13	5.5%	13.6%	25.5%	34.5%	45.5%	10.0%
Comparative	12.9%	17.2%	23.7%	37.6%	77.4%	8.0%
Example 7
Comparative	13.8%	19.3%	28.3%	36.6%	77.9%	8.0%
Example 9

TABLE 5
Excitation power and deterioration coefficient
under different gauge factors
	Pe(VA/kg)
	Gauge Factor
Category	0%	2.0%	4.0%	6.0%	8.0%	10.0%
Comparative	0.145	0.18	0.351	0.507	1.022	1.441
Example 3
Example 4	0.131	0.144	0.165	0.176	0.24	0.302
Example 5	0.125	0.138	0.16	0.185	0.205	0.401
Example 6	0.12	0.132	0.154	0.176	0.207	0.354
Example 12	0.137	0.148	0.164	0.185	0.215	0.367
Example 13	0.145	0.158	0.179	0.192	0.208	0.42
Comparative	0.13	0.178	0.33	0.428	0.854	1.025
Example 7
Comparative	0.167	0.195	0.225	0.403	0.784	0.998
Example 9

TABLE 5
Excitation power and deterioration coefficient
under different gauge factors (Continued table)
	Deterioration Coefficient of Pe	Maximum
	Gauge Factor	Gauge
Category	2.0%	4.0%	6.0%	8.0%	10.0%	Factor
Comparative	24.1%	142.1%	249.7%	604.8%	893.8%	2.0%
Example 3
Example 4	9.9%	26.0%	34.4%	83.2%	130.5%	6.0%
Example 5	10.4%	28.0%	48.0%	64.0%	220.8%	6.0%
Example 6	10.0%	28.3%	46.7%	72.5%	195.0%	6.0%
Example 12	8.0%	19.7%	35.0%	56.9%	167.9%	6.0%
Example 13	9.0%	23.4%	32.4%	43.4%	189.7%	8.0%
Comparative	36.9%	153.8%	229.2%	556.9%	688.5%	2.0%
Example 7
Comparative	16.8%	34.7%	141.3%	369.5%	497.6%	4.0%
Example 9

Tables 4 and 5 clearly showed that iron-based amorphous alloys undergone a certain degree of performance deterioration due to the influence of stress, and the performance deterioration coefficient increased as the deformation coefficient increased. Comparing the loss and the excitation power of each component, it could be found that the deterioration of the excitation power significantly exceeded its loss. The allowable deterioration coefficient of excitation power was 6%, while the allowable deterioration coefficient of loss was 10%. That is, the application of external stress to the amorphous strip has a greater effect on the excitation power.

Comparing the examples with comparative examples, it could be found that there was a big difference in the performance deterioration coefficient of strips with different compositions when subjected to stress. The loss of the amorphous alloy strips in examples 4 to 6 and 12 to 13 allowed a gauge factor of 10%, and excitation power of examples 4 to 6 and 12 to 13 allowed a deterioration coefficient of 6%. Considering the bucket effect of the performance comprehensively, the allowable deterioration coefficient of the embodiments was 6%. The allowable gauge factors for the losses and excitation power of the comparative example were 8% and 2%, respectively, and the allowable deterioration factor for the comparative example was 2%. In view of above, the annealed post-amorphous tape embodiment had significant advantages in the resistance to stress sensibility, allowing greater deformation and ensuring that the material properties were within an acceptable range.

The above description of the embodiments is merely for helping to understand the method of the present disclosure and its core idea. It should be pointed out that one of ordinary skill in the art can also make several improvements and modifications to the present disclosure without departing from the principles of the present invention, and these improvements and modifications also fall into the protection scope of the claims of the present invention.

The above description of the disclosed embodiments enables one of ordinary skill in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one of ordinary skill in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present disclosure will not be limited to the embodiments shown herein but will be consistent with the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An iron-based amorphous alloy represented by formula (I):

FeaBbSic   (I);

wherein a, b and c are each independently atomic percentages of corresponding components, 79.5≤a≤82.5, 11.0≤b≤13.5, 6.5≤c≤8.5, and a+b+c=100.

2. The iron-base amorphous alloy according to claim 1, wherein the saturation magnetic induction of the iron-based amorphous alloy is ≥1.60 T.

3. The iron-base amorphous alloy according to claim 1, wherein the atomic percentage of Fe is 80.0≤a≤81.5.

4. The iron-base amorphous alloy according to claim 1, wherein the atomic percentage of B is 11.0≤b≤12.5.

5. The iron-base amorphous alloy according to claim 1, wherein the atomic percentage of Si is 7.0≤c≤8.0.

6. The iron-base amorphous alloy according to claim 1, wherein in the iron-based amorphous alloy a=80.0, 12.0≤b≤13.0, and 7.0≤c≤8.0.

7. The iron-base amorphous alloy according to claim 1, wherein in the iron-based amorphous alloy a=80.5, 11.5≤b≤12.5, and 7.0≤c≤8.0.

8. The iron-base amorphous alloy according to claim 1, wherein in the iron-based amorphous alloy 81.0≤a≤81.5, 11.0≤b≤13.0, and 7.0≤c≤8.0.

9. A method for preparing an iron-based amorphous alloy strip represented by formula (I), comprising:

preparing raw materials according to the atomic percentages indicated in formula (I); smelting the raw materials; heating and insulating the molten liquid after smelting;

performing single roller rapid quenching to obtain the iron-based amorphous alloy strip; FeaBbSic   (I);

wherein a, b and c are each independently atomic percentages of corresponding components; 79.5≤a≤82.5, 11.0≤b≤13.5, 6.5≤c≤8.5, and a+b+c=100.

10. The method according to claim 9, further comprising subjecting the iron-based amorphous alloy to heat treatment after the single roller rapid quenching.

11. The method according to claim 10, wherein prior to the heat treatment, further comprising winding the iron-based amorphous alloy into a sample ring with an inside diameter of 50.5 mm and an outside diameter from 53.5 to 54 mm, wherein allowable gauge factor of the sample ring loss is 10.0% and allowable gauge factor of the excitation power is 6% after heat treatment.

12. The method according to the claim 10, wherein the coercive force of an iron-based amorphous alloy strip after heat treatment is ≤3.5 A/m; under a condition of 50 Hz and 1.35 T, excitation power of the iron-based amorphous alloy strip after heat treatment is ≤0.1450 VA/kg, and core loss is ≤0.1100 W/kg; and under a condition of 50 Hz and 1.40 T, excitation power of the iron-based amorphous alloy strip after heat treatment is ≤0.1700 VA/kg, and core loss is ≤0.1500 W/kg.

13. The method according to claim 10, wherein the iron-based amorphous alloy strip is in completely amorphous phase with a limit thickness of at least 75 μm and a shearable limit thickness of at least 29 μm.