CN114914049A

CN114914049A - Ultra-microcrystalline iron core with stable performance for current transformer and production method thereof

Info

Publication number: CN114914049A
Application number: CN202210449624.6A
Authority: CN
Inventors: 徐自平
Original assignee: Anhui Develop Noncrystal Equipment Co ltd
Current assignee: Anhui Develop Noncrystal Equipment Co ltd
Priority date: 2022-04-25
Filing date: 2022-04-25
Publication date: 2022-08-16
Anticipated expiration: 2042-04-25
Also published as: CN114914049B

Abstract

The invention discloses an ultracrystalline iron core with stable performance for a current transformer and a production method thereof, wherein the ultracrystalline iron core comprises the following chemical components in percentage by weight: 2.8 to 3.8 percent of Nb, 8.2 to 10.0 percent of B, 11.5 to 14.0 percent of Si, 0.81 to 1.5 percent of Cu, and the balance of Fe and inevitable impurities; the method adopts the processes of smelting, alloy melting, strip preparation, winding, annealing and packaging to produce the ultra-crystalline iron core, the obtained ultra-crystalline iron core has stable performance, the saturation magnetic induction Bs is 1.0-1.2T, the ultra-crystalline iron core products produced in the component range can be divided into 20 products with different series grades according to the magnetization curve quality value and the quality standard value, the magnetization curve data of the products can completely reflect the relation between the soft magnetic material H and the soft magnetic material B, and the magnetic induction strength and the induced potential value calculated according to the data are consistent with the actual test value.

Description

Ultra-microcrystalline iron core with stable performance for current transformer and production method thereof

Technical Field

The invention belongs to the technical field of an ultracrystalline iron core, and particularly relates to an ultracrystalline iron core with stable performance for a current transformer and a production method thereof.

Background

The current transformer is composed of a closed iron core and a winding, is specially used for measuring the current and the electric energy of an electric power system, and meets the specified accuracy requirement under the normal working condition so as to ensure the accuracy of measurement. However, the current transformers used in the power system often have a large overcurrent flowing through the primary winding due to a system fault or operation. In this case, it is desirable that the secondary current does not increase strictly in proportion to avoid the impact of large current on the instruments and meters connected to the secondary circuit. The ultra-crystalline iron core used in the current transformer generally requires that the saturation magnetic induction intensity Bs is between 1.0 and 1.2T, so that after a large overcurrent flows through a primary winding due to system faults or operation, secondary current can be effectively controlled, and instruments and meters connected with a secondary circuit are prevented from being impacted by large current.

However, in the prior art, the performance fluctuation of the iron core produced in the set composition range is large, the consistency of the saturation magnetic induction Bs is low, and thus the stability of the current transformer product of the terminal customer is low, and finally the complaint rate of the terminal customer is high.

Disclosure of Invention

In order to solve the problems, the ultracrystalline iron core with stable performance used in the current transformer and the production method thereof are provided, the ultracrystalline iron core produced in the composition range disclosed by the invention has high stability and consistency, and the complaint rate of terminal customers is reduced.

The technical scheme adopted by the invention is as follows:

an ultracrystalline iron core with stable performance for a current transformer comprises the following chemical components in percentage by weight: 2.8-3.8% of Nb, 8.2-10.0% of B, 8.5-14.0% of Si, 0.81-1.5% of Cu, and the balance of pure Fe and inevitable impurities, wherein the content of the impurities is less than 0.025%.

Further, the ultracrystalline iron core with stable performance for the current transformer preferably comprises the following chemical components in percentage by weight: 2.8 to 3.8 percent of Nb, 8.2 to 10.0 percent of B, 11.5 to 14.0 percent of Si, 0.81 to 1.5 percent of Cu and 71 to 75 percent of pure Fe.

The ultracrystalline iron core can be divided into 1-20 grades and 20 products with different series grades in the above component range according to a magnetization curve, a magnetization curve quality value and a quality standard value. The relationship between the soft magnetic material H (A/m) and B (T) can be completely reflected, wherein H is the magnetic field intensity, B is the magnetic induction intensity, and the magnetic induction intensity and the induced potential value calculated according to the data are consistent with the actual test value.

The saturation magnetic induction Bs of the ultracrystalline iron core with stable performance is 1.0-1.2T.

The invention also provides a production method of the ultracrystalline iron core with stable performance for the current transformer, which comprises the following steps: smelting to obtain an alloy, melting the alloy, preparing a strip, winding, annealing and packaging.

In the smelting step, ferroboron, ferroniobium, copper and pure iron are sequentially added into a medium-frequency induction furnace, a deslagging agent is added after smelting is carried out for 35-45min, the smelting is continued to be carried out for 65-75min under the protection of argon, the deslagging agent is added again, then metal silicon is added after pure iron is completely melted, the temperature is raised to 1560 ℃, the temperature is kept for 20min, then the temperature of molten steel is cooled to 1200 ℃ after 70min, and steel is tapped. In the smelting step, the materials need to be added according to the feeding sequence strictly, otherwise, more oxidation impurities appear, which is not favorable for the stability of the performance of the finally produced ultracrystalline iron core.

The amount of the slag removing agent added each time is 130-160g/t steel, and in the steps, the slag removing agent is added in two batches to obtain relatively pure molten steel.

In the step of melting the alloy, a limestone layer is laid on the lower layer of the alloy during feeding so as to further remove slag in the step of melting the alloy and increase the fluidity of molten steel during spraying during preparation of subsequent strips, and after the temperature is raised to 1150-.

The addition amount of the limestone is 1.5-2% of the addition amount of the alloy.

Further, in the alloy melting step, 80kg of alloy is paved at the bottom layer of the melting furnace during feeding, 5-8kg of limestone is paved above the alloy layer, and then 380kg of alloy is continuously added.

In the strip preparation step, the melted alloy is sprayed on the surface of a cooled copper roller to form a continuous amorphous alloy strip with the thickness of 30-40 mu m and the width of 5-45 mm.

In the annealing step, a step annealing mode is adopted, and the temperature is firstly preserved for 70-130 min at 435-; then heating to 475-.

Further, in the annealing step, firstly, the temperature is raised to 435-; then continuously raising the temperature to 475-.

The method adopts a step annealing mode to carry out annealing, the temperature is increased to 435-. After the ultracrystalline iron core with stable performance used in the current transformer is subjected to the annealing process, the ultracrystalline iron core has stable performance and higher consistency.

The content of Nb, B, Si, Cu and Fe is accurately controlled, the purity of molten steel is fully ensured in the steps of smelting and alloy melting, and the superfine crystal iron core is produced by combining a subsequent step annealing process, and has a microstructure that fine nano-crystalline grains are randomly and uniformly distributed on an amorphous matrix, the grain diameter is 10-20nm, the superfine crystal iron core has stable performance, and the saturation magnetic induction intensity Bs is 1.0-1.2T.

Compared with the prior art, the invention has the following beneficial effects: the performance is stable and reliable, the consistency is high, and the complaint rate of terminal customers is reduced. The ultracrystalline iron core products produced in the component range of the invention can be divided into 1-20 grades according to the quality values and quality standard values of the magnetization curves, 20 products with different series grades can be obtained, the magnetization curve data of the products can completely reflect the relationship between the soft magnetic material H (A/m) and B (T), H is the magnetic field intensity, B is the magnetic induction intensity, and the magnetic induction intensity and the induced potential value calculated according to the data are consistent with the actual test value.

Drawings

FIG. 1 is a magnetization curve of an ultracrystalline iron core in example 1;

FIG. 2 is data of the magnetization curves of FIG. 1;

FIG. 3 is a graph showing the magnetization curve and magnetization curve data of the ultra-crystalline core in example 2;

FIG. 4 shows magnetization curves and magnetization curve data of the ultra-crystalline core in example 3;

FIG. 5 shows magnetization curves and magnetization curve data of the ultra-crystalline core in example 4;

FIG. 6 shows magnetization curves and magnetization curve data of the ultra-crystalline core in example 5;

FIG. 7 shows magnetization curves and magnetization curve data of the ultra-crystalline core in example 6;

FIG. 8 is a graph showing the magnetization curve and magnetization curve data of the ultra-crystalline core in example 7;

FIG. 9 is a graph showing the magnetization curve and magnetization curve data of the ultra-crystalline core in example 8;

FIG. 10 is a graph showing the magnetization curve and magnetization curve data of the ultra-crystalline core in example 9;

FIG. 11 is a graph showing the magnetization curve and magnetization curve data of the ultra-crystalline core in example 10;

FIG. 12 is a graph showing the magnetization curves and magnetization curve data of the ultra-crystalline core in example 11;

FIG. 13 is a graph showing the magnetization curves and magnetization curve data of an ultracrystalline core in example 12;

FIG. 14 is a graph showing the magnetization curve and magnetization curve data of the ultra-crystalline core in example 13;

FIG. 15 is a graph showing the magnetization curve and magnetization curve data of the ultra-crystalline core in example 14;

FIG. 16 is a graph showing the magnetization curve and magnetization curve data of the ultra-crystalline core in example 15;

FIG. 17 is a graph showing the magnetization curves and magnetization curve data of the ultra-crystalline core in example 16;

FIG. 18 is a graph showing the magnetization curves and magnetization curve data of the ultra-crystalline core in example 17;

FIG. 19 is a graph showing the magnetization curves and magnetization curve data of the ultra-crystalline core in example 18;

FIG. 20 is a graph showing the magnetization curves and magnetization curve data of the ultra-crystalline core in example 19;

FIG. 21 shows the magnetization curve and magnetization curve data of the ultra-crystalline core in example 20.

Detailed Description

The invention provides an ultracrystalline iron core with stable performance for a current transformer, which comprises the following chemical components in percentage by weight: 2.8 to 3.8 percent of Nb, 8.2 to 10.0 percent of B, 11.5 to 14.0 percent of Si, 0.81 to 1.5 percent of Cu, and the balance of Fe and inevitable impurities.

The production method of the ultracrystalline iron core with stable performance for the current transformer comprises the following steps: smelting to obtain an alloy, melting the alloy, preparing a strip, winding, annealing and packaging.

In the smelting step, ferroboron, ferroniobium, copper and pure iron are sequentially added into a medium-frequency induction furnace, a deslagging agent is added after smelting is carried out for 35-45min, the smelting is continued to be carried out for 65-75min under the protection of argon, the deslagging agent is added again, then metal silicon is added after pure iron is completely melted, the temperature is raised to 1560 ℃, the temperature is kept for 20min, then the temperature of molten steel is cooled to 1200 ℃ after 70min, and steel is tapped.

The amount of the slag removing agent added each time is 130-160g/t steel;

in the step of melting the alloy, 80kg of alloy is paved at the bottom layer of the melting furnace during feeding, then 8kg of limestone is paved above the alloy layer, 380kg of alloy is continuously added, stirring is carried out after the temperature is raised to 1150-plus 1200 ℃, so that the limestone floats to the surface of the molten steel, and slag is fished.

In the strip preparation step, the melted alloy is sprayed on the surface of a cooled copper roller to form a continuous amorphous alloy strip with the thickness of 30-40 mu m and the width of 5-45 mm;

in the annealing step, a step annealing mode is adopted, and the temperature is raised to 435 ℃ and 445 ℃ at the heating rate of 5-8 ℃/min and is kept for 70-130 min; then continuously raising the temperature to 475-.

The present invention will be described in detail with reference to examples.

TABLE 1 composition and weight percentage of the ultracrystalline iron core in each of examples and comparative examples

	Nb	B	Si	Cu	Fe and trace impurities
						Example 1 (series 1)	2.80	8.20	13.19	0.81	75.00
Example 2 (series 2)	2.85	8.30	13.23	0.82	74.80
						Example 3 (series 3)	2.90	8.35	13.42	0.83	74.50
Example 4 (series 4)	2.95	8.40	13.61	0.84	74.20
						Example 5 (series 5)	3.00	8.45	13.69	0.86	74.00
Example 6 (series 6)	3.05	8.50	13.87	0.88	73.70
						Example 7 (series 7)	3.10	9.00	13.60	0.90	73.40
Example 8 (series 8)	3.15	9.50	12.85	1.5	73.00
						Example 9 (series 9)	3.20	9.45	13.10	1.45	72.80
Example 10 (series 10)	3.25	9.40	14.00	1.40	71.95
						Example 11 (series 11)	3.30	9.50	13.80	1.50	71.90
Example 12 (series 12)	3.75	9.90	13.90	1.45	71.00
						Example 13 (series 13)	3.40	8.70	13.50	1.35	73.05
Example 14 (series 14)	3.45	8.80	13.20	1.30	73.25
						Example 15 (series 15)	3.50	8.90	12.80	1.25	73.55
Example 16 (series 16)	3.55	9.00	12.50	1.15	73.80
						Example 17 (series 17)	3.60	9.10	12.25	1.05	74.00
Example 18 (series 18)	3.65	9.50	12.00	1.00	73.85
						Example 19 (series 19)	3.70	9.70	11.75	0.95	73.90
Example 20 (series 20)	3.80	10.00	11.50	0.90	73.80

Example 1

An ultracrystalline iron core with stable performance for use in a current transformer, whose chemical composition and weight percentage are shown in example 1 in table 1.

The production method of the ultracrystalline iron core with stable performance for the current transformer comprises the following steps:

(1) smelting: sequentially adding ferroboron, ferroniobium, copper and pure iron into a medium-frequency induction furnace, smelting for 35-45min, adding a deslagging agent, wherein the addition amount of the deslagging agent is 140g/t of steel, continuously smelting for 65-75min under the protection of argon, then adding the deslagging agent again, wherein the addition amount of the deslagging agent is 140g/t of steel, then adding metal silicon after pure iron is completely melted, heating to 1560 ℃, preserving heat for 20min, then cooling for 70min, reducing the temperature of molten steel to 1200 ℃, tapping, and cooling to obtain an alloy;

(2) melting the alloy: during feeding, laying 80kg of alloy obtained in the step (1) on the bottom layer of a melting furnace, laying 8kg of limestone above an alloy layer, continuously adding 380kg of alloy, stirring after the temperature is raised to 1200 ℃ to enable the limestone to float to the surface of molten steel, and dragging slag, wherein the total melting time is 80 min;

(3) strip preparation: spraying the melted alloy on the surface of a cooled copper roller to form a continuous amorphous alloy strip with the thickness of 35 mu m and the width of 20 mm;

(4) winding: winding the amorphous alloy strip obtained in the step (3) into a ring-shaped iron core with the outer diameter of 125mm, the inner diameter of 90mm and the height of 20 mm;

(5) step annealing: firstly, heating to 435 ℃ at a heating rate of 5 ℃/min, and keeping the temperature for 100 min; continuing to heat to 475 ℃ at the heating rate of 1.0 ℃/min for 50min, continuing to heat to 495 ℃ at the heating rate of 0.10 ℃/min for 85min, continuing to heat to 500 ℃ at the heating rate of 0.15 ℃/min for 40min, continuing to heat to 515 ℃ at the heating rate of 0.4 ℃/min for 15min, continuing to heat to 570 ℃ at the heating rate of 2.0 ℃/min for 55min, and then cooling to room temperature along with the furnace;

(6) and (6) packaging.

Example 2

An ultracrystalline iron core with stable performance for a current transformer, whose chemical composition and weight percentage are shown in example 2 in table 1.

(5) step annealing: firstly, heating to 435 ℃ at a heating rate of 5.5 ℃/min and preserving heat for 100 min; continuing to heat to 475 ℃ at the heating rate of 1.0 ℃/min for 50min, continuing to heat to 495 ℃ at the heating rate of 0.10 ℃/min for 85min, continuing to heat to 500 ℃ at the heating rate of 0.15 ℃/min for 40min, continuing to heat to 515 ℃ at the heating rate of 0.4 ℃/min for 15min, continuing to heat to 570 ℃ at the heating rate of 2.0 ℃/min for 55min, and then cooling to room temperature along with the furnace;

(6) and (6) packaging.

Example 3

An ultra-crystalline iron core with stable performance for a current transformer, whose chemical composition and weight percentage are shown in example 3 in table 1.

(5) step annealing: firstly, heating to 435 ℃ at a heating rate of 5.5 ℃/min and keeping the temperature for 100 min; continuing to heat to 475 ℃ at the heating rate of 1.0 ℃/min for 50min, continuing to heat to 495 ℃ at the heating rate of 0.10 ℃/min for 85min, continuing to heat to 500 ℃ at the heating rate of 0.15 ℃/min for 40min, continuing to heat to 515 ℃ at the heating rate of 0.5 ℃/min for 15min, continuing to heat to 570 ℃ at the heating rate of 2.0 ℃/min for 55min, and then cooling to room temperature along with the furnace;

(6) and (6) packaging.

Example 4

An ultra-crystalline iron core with stable performance for a current transformer, which has chemical compositions and weight percentages as shown in example 4 in table 1.

(2) melting the alloy: during feeding, laying 80kg of alloy obtained in the step (1) on the bottom layer of a melting furnace, laying 8kg of limestone above an alloy layer, continuously adding 380kg of alloy, stirring after the temperature is raised to 1150 ℃ to enable the limestone to float to the surface of molten steel, and dragging slag, wherein the total melting time is 80 min;

(5) step annealing: firstly, heating to 435 ℃ at a heating rate of 5 ℃/min, and preserving heat for 130 min; continuing to heat to 475 ℃ at the heating rate of 0.5 ℃/min for 55min, continuing to heat to 490 ℃ at the heating rate of 0.10 ℃/min for 60min, continuing to heat to 500 ℃ at the heating rate of 0.20 ℃/min for 20min, continuing to heat to 515 ℃ at the heating rate of 0.5 ℃/min for 20min, continuing to heat to 570 ℃ at the heating rate of 1.5 ℃/min for 55min, and then cooling to room temperature along with the furnace;

(6) and (6) packaging.

Example 5

An ultracrystalline iron core with stable performance for a current transformer, whose chemical composition and weight percentage are shown in example 5 in table 1.

(2) melting the alloy: during feeding, laying 80kg of alloy obtained in the step (1) on the bottom layer of a melting furnace, laying 6kg of limestone above an alloy layer, continuously adding 380kg of alloy, stirring after the temperature is raised to 1200 ℃ to enable the limestone to float to the surface of molten steel, and dragging slag, wherein the total melting time is 80 min;

(5) step annealing: firstly, heating to 435 ℃ at a heating rate of 6 ℃/min and preserving heat for 100 min; continuing to heat to 475 ℃ at the heating rate of 1.0 ℃/min for 50min, continuing to heat to 495 ℃ at the heating rate of 0.10 ℃/min for 85min, continuing to heat to 500 ℃ at the heating rate of 0.15 ℃/min for 40min, continuing to heat to 515 ℃ at the heating rate of 0.4 ℃/min for 15min, continuing to heat to 570 ℃ at the heating rate of 2.0 ℃/min for 55min, and then cooling to room temperature along with the furnace;

(6) and (6) packaging.

Example 6

An ultra-crystalline iron core with stable performance for a current transformer, whose chemical composition and weight percentage are shown in example 6 in table 1.

(1) smelting: sequentially adding ferroboron, ferroniobium, copper and pure iron into a medium-frequency induction furnace, smelting for 35-45min, adding a deslagging agent, wherein the addition amount of the deslagging agent is 140g/t of steel, continuously smelting for 65-75min under the protection of argon, then adding the deslagging agent again, wherein the addition amount of the deslagging agent is 140g/t of steel, then adding metal silicon after pure iron is completely melted, heating to 1560 ℃, preserving heat for 20min, then cooling for 70min, reducing the temperature of molten steel to 1200 ℃, tapping, and cooling to obtain an alloy.

(5) step annealing: firstly, heating to 440 ℃ at a heating rate of 7 ℃/min, and preserving heat for 100 min; continuing to heat to 480 ℃ at the heating rate of 0.5 ℃/min for 50min, continuing to heat to 493 ℃ at the heating rate of 0.15 ℃/min for 70min, continuing to heat to 500 ℃ at the heating rate of 0.20 ℃/min for 40min, continuing to heat to 510 ℃ at the heating rate of 0.4 ℃/min for 25min, continuing to heat to 565 ℃ at the heating rate of 2.0 ℃/min for 60min, and then cooling to room temperature along with the furnace;

(6) and (6) packaging.

Example 7

An ultra-crystalline iron core with stable performance for a current transformer, whose chemical composition and weight percentage are shown in example 7 of table 1.

(1) smelting: sequentially adding ferroboron, ferroniobium, copper and pure iron into a medium-frequency induction furnace, smelting for 35-45min, adding a deslagging agent, wherein the addition amount of the deslagging agent is 140g/t of steel, continuously smelting for 65-75min under the protection of argon, then adding the deslagging agent again, wherein the addition amount of the deslagging agent is 140g/t of steel, then adding metal silicon after the purification of the iron is finished, heating to 1560 ℃, preserving the heat for 20min, then cooling for 70min, reducing the temperature of molten steel to 1200 ℃, tapping, and cooling to obtain an alloy.

(2) Melting the alloy: during feeding, laying 80kg of alloy obtained in the step (1) on the bottom layer of a melting furnace, laying 8kg of limestone above an alloy layer, continuously adding the alloy to 380kg, stirring after the temperature is raised to 1200 ℃ to enable the limestone to float to the surface of molten steel, and dragging slag, wherein the total melting time is 80 min;

(5) step annealing: firstly, heating to 435 ℃ at a heating rate of 7 ℃/min, and preserving heat for 130 min; continuing to heat to 485 ℃ at the heating rate of 1.0 ℃/min, preserving heat for 50min, continuing to heat to 490 ℃ at the heating rate of 0.15 ℃/min, preserving heat for 70min, continuing to heat to 500 ℃ at the heating rate of 0.15 ℃/min, preserving heat for 30min, continuing to heat to 510 ℃ at the heating rate of 0.3 ℃/min, preserving heat for 30min, continuing to heat to 565 ℃ at the heating rate of 1.5 ℃/min, preserving heat for 45min, and then cooling to room temperature along with the furnace;

(6) and (6) packaging.

Example 8

An ultracrystalline iron core with stable performance for a current transformer, whose chemical composition and weight percentage are shown in example 8 in table 1.

(1) smelting: sequentially adding ferroboron, ferroniobium, copper and pure iron into a medium-frequency induction furnace, smelting for 35-45min, adding a deslagging agent, wherein the addition amount of the deslagging agent is 140g/t of steel, continuously smelting for 65-75min under the protection of argon, then adding the deslagging agent again, wherein the addition amount of the deslagging agent is 140g/t of steel, then adding metal silicon after the purification of the iron is finished, heating to 1560 ℃, preserving heat for 20min, then cooling for 70min, reducing the temperature of molten steel to 1200 ℃, tapping, and cooling to obtain an alloy;

(5) step annealing: firstly, heating to 435 ℃ at a heating rate of 7 ℃/min and preserving heat for 100 min; continuing to heat to 475 ℃ at the heating rate of 1.0 ℃/min for 50min, continuing to heat to 495 ℃ at the heating rate of 0.10 ℃/min for 85min, continuing to heat to 500 ℃ at the heating rate of 0.15 ℃/min for 40min, continuing to heat to 515 ℃ at the heating rate of 0.4 ℃/min for 15min, continuing to heat to 570 ℃ at the heating rate of 1.5 ℃/min for 55min, and then cooling to room temperature along with the furnace;

(6) and (6) packaging.

Example 9

An ultra-crystalline iron core with stable performance for a current transformer, whose chemical composition and weight percentage are shown in example 9 in table 1.

(2) Melting the alloy: during feeding, laying 80kg of alloy obtained in the step (1) on the bottom layer of a melting furnace, laying 8kg of limestone above an alloy layer, continuously adding 380kg of alloy, stirring to enable the limestone to float to the surface of molten steel after the temperature is raised to 1180 ℃, and carrying out slag removal, wherein the total melting time is 80 min;

(5) step annealing: firstly, heating to 445 ℃ at a heating rate of 7 ℃/min and preserving heat for 75 min; continuing to heat to 480 ℃ at the heating rate of 1.0 ℃/min for 55min, continuing to heat to 495 ℃ at the heating rate of 0.20 ℃/min for 90min, continuing to heat to 500 ℃ at the heating rate of 0.15 ℃/min for 60min, continuing to heat to 510 ℃ at the heating rate of 0.5 ℃/min for 30min, continuing to heat to 570 ℃ at the heating rate of 2.0 ℃/min for 45min, and then cooling to room temperature along with the furnace;

(6) and (6) packaging.

Example 10

An ultra-crystalline iron core with stable performance for use in a current transformer, the chemical composition and weight percentage of which are shown in example 10 of table 1.

(2) Melting the alloy: laying 80kg of alloy obtained in the step (1) on the bottom layer of a melting furnace during feeding, laying 8kg of limestone above the alloy layer, continuously adding 380kg of alloy, stirring after the temperature is raised to 1200 ℃ to enable the limestone to float to the surface of molten steel, and fishing slag, wherein the total melting time is 80 min;

(6) and (7) packaging.

Example 11

An ultra-microcrystalline iron core with stable performance for a current transformer, which comprises the chemical components and weight percentages shown in example 11 in table 1; the preparation method is the same as that of example 10.

Example 12

An ultra-microcrystalline iron core with stable performance for a current transformer, which comprises the chemical components and weight percentages shown in example 12 in table 1; the preparation method is the same as that of example 10.

Example 13

An ultra-microcrystalline iron core with stable performance for a current transformer, which comprises the chemical components and weight percentages shown in example 13 in table 1; the preparation method is the same as that of example 10.

Example 14

An ultra-crystalline iron core with stable performance for a current transformer, the chemical composition and weight percentage of which are shown in example 14 in table 1; the preparation method is the same as that of example 10.

Example 15

An ultra-microcrystalline iron core with stable performance for a current transformer, which comprises the chemical components and weight percentages shown in example 15 in table 1; the preparation method is the same as that of example 10.

Example 16

An ultra-microcrystalline iron core with stable performance for a current transformer, which comprises the chemical components and weight percentages shown in example 16 in table 1; the preparation method is the same as that of example 10.

Example 17

An ultracrystalline iron core with stable performance for a current transformer, the chemical composition and weight percentage of which are shown in example 17 in table 1; the preparation method is the same as that of example 10.

Example 18

An ultra-microcrystalline iron core with stable performance for a current transformer, which comprises the chemical components and weight percentages shown in example 18 in table 1; the preparation method is the same as that of example 10.

Example 19

An ultra-microcrystalline iron core with stable performance for a current transformer, which comprises the chemical components and weight percentages shown in example 19 in table 1; the preparation method is the same as that of example 10.

Example 20

An ultra-microcrystalline iron core with stable performance for a current transformer, which comprises the chemical components and weight percentages shown in example 20 in table 1; the preparation method is the same as that of example 10.

The performance of the ultracrystalline iron core produced in the above embodiments was tested by the national institute of metrology science with reference to the method for measuring the ring-shaped sample of the alternating magnetic performance of the GB/T3658-2008 soft magnetic material, and the corresponding magnetization curves and the data corresponding to the magnetization curves are shown in fig. 1-21.

In the figure, the ratio of the magnetic induction B to the magnetic field H is the magnetic permeability μ, μ ═ B/H, and as can be seen from fig. 1 to 21, the ultra-crystalline iron core product can be divided into 20 series grades within the range of the composition defined in the present invention, and the saturation magnetic induction Bs of the iron core of each grade is stably maintained between 1.0T and 1.2T; the magnetization curve data of the ultracrystalline iron core product in the embodiments can completely reflect the relationship between the soft magnetic material H (a/m) and b (t), and the magnetic induction intensity, the induced potential value and the actual test value calculated according to the data can keep highly consistent.

The above detailed description of an ultra-microcrystalline core having stable performance for use in a current transformer and a method for manufacturing the same with reference to the embodiments is illustrative and not restrictive, and several embodiments may be enumerated within the scope of the limitations, so that changes and modifications may be made without departing from the spirit of the present invention.

Claims

1. An ultracrystalline iron core with stable performance used in a current transformer is characterized by comprising the following chemical components in percentage by weight: 2.8 to 3.8 percent of Nb, 8.2 to 10.0 percent of B, 11.5 to 14.0 percent of Si, 0.81 to 1.5 percent of Cu, and the balance of Fe and inevitable impurities.

2. The ultra-microcrystalline iron core with stable performance for the current transformer as claimed in claim 1, comprising the following chemical components by weight percentage: 2.8 to 3.8 percent of Nb, 8.2 to 10.0 percent of B, 11.5 to 14.0 percent of Si, 0.81 to 1.5 percent of Cu and 71 to 75 percent of Fe.

3. The ultra-microcrystalline iron core with stable performance for use in a current transformer according to claim 1 or 2, wherein said ultra-microcrystalline iron core with stable performance has a saturation induction Bs of 1.0-1.2T.

4. A method for producing an ultracrystalline iron core with stable performance for use in a current transformer according to any one of claims 1 to 3, characterized in that the production method comprises the steps of: smelting to obtain an alloy, melting the alloy, preparing a strip, winding, annealing and packaging.

5. The production method of claim 4, wherein in the smelting step, ferroboron, ferroniobium, copper and pure iron are sequentially added into a medium-frequency induction furnace, a deslagging agent is added after smelting is carried out for 35-45min, the deslagging agent is added after smelting is continued to 65-75min under the protection of argon gas, then metal silicon is added after pure iron is completely melted, the temperature is raised to 1560 ℃, the temperature is kept for 20min, then the temperature of molten steel is cooled for 70min, the molten steel is cooled to 1200 ℃, steel is tapped, and the alloy is cooled.

6. The production method as claimed in claim 5, wherein the amount of slag removing agent added at a time is 130-160g/t steel.

7. The production method as claimed in claim 5, wherein in the alloy melting step, a limestone layer is laid on the lower layer of the alloy during feeding, stirring is carried out after the temperature is raised to 1150-1200 ℃ so that limestone floats to the surface of the molten steel, and slag is fished.

8. The production method according to claim 5, wherein in the strip preparation step, the molten alloy is sprayed onto the surface of a cooled copper roller to form a continuous amorphous alloy strip having a thickness of 30-40 μm and a width of 5-45 mm.

9. The method as claimed in claim 5, wherein the annealing step is performed by a step annealing method, and the annealing is performed by first performing heat preservation at 435-; then heating to 475-.

10. The production method as claimed in claim 9, wherein the temperature is raised to 435-; then continuously raising the temperature to 475-.