CN113528969A

CN113528969A - Ultrahigh magnetic induction non-oriented silicon steel, manufacturing method thereof and application thereof in automobile generator production

Info

Publication number: CN113528969A
Application number: CN202110818854.0A
Authority: CN
Inventors: 陆天林; 裴英豪; 施立发; 朱涛; 胡柯
Original assignee: Maanshan Iron and Steel Co Ltd
Current assignee: Maanshan Iron and Steel Co Ltd
Priority date: 2021-07-20
Filing date: 2021-07-20
Publication date: 2021-10-22

Abstract

The invention provides ultrahigh magnetic induction non-oriented silicon steel, a manufacturing method thereof and application in the production of automobile generators, wherein the silicon steel comprises the following components: c: less than or equal to 0.005%, Si: 0.5-1.2%, Mn: 0.1-0.5%, P: 0.01-0.1%, S: less than or equal to 0.004%, Al: less than or equal to 0.005 percent, N: less than or equal to 0.005 percent, Ti: less than or equal to 0.003 percent, and the balance of iron and inevitable impurities. Through composition design, the CSP thin slab continuous casting and rolling process and the normalizing process are matched, noble metal elements are not added, and the method has the advantages of short flow, low cost, high magnetic induction and stable performance; the iron core of the automobile generator produced by the invention has the advantages that the weight can be reduced by more than 15% compared with the iron core produced by conventional products, the size of the generator is reduced, and the requirements of miniaturization and high efficiency of the automobile generator are met.

Description

Ultrahigh magnetic induction non-oriented silicon steel, manufacturing method thereof and application thereof in automobile generator production

Technical Field

The invention belongs to the technical field of metallurgical materials, and particularly relates to ultrahigh magnetic induction non-oriented silicon steel, a manufacturing method thereof and application thereof in production of an automobile generator.

Background

The development of science and technology inevitably drives the innovation of vehicles, the core of the vehicles is motors, and the core of the motors is non-oriented silicon steel. In order to meet the development trend of motor miniaturization, low energy consumption and high efficiency, the non-oriented silicon steel is required to have lower iron loss and higher magnetic induction, and the magnetic induction and the iron loss are a pair of contradictory performances. How to consider the iron loss and the magnetic induction is the topic that the non-oriented silicon steel is not changed after the ancient times.

The automobile generator is one of important components of an automobile, and can charge a storage battery when the automobile works, so that the automobile can be ensured to have sufficient electric quantity for lighting, air conditioning, sound equipment and other electric equipment. The final purpose of automobile generator manufacturing enterprises is to improve the efficiency of the generator and reduce the size of the generator, and a threshold value for improving the efficiency of the generator through optimization of a processing technology in a manufacturing factory is limited, so that higher requirements are provided for a stator core component and a rotor core component of the generator.

A large number of researches show that the magnetic induction of the non-oriented silicon steel can be improved by adjusting the process of the key working procedure or adding Sn, Sb and Sn/Sb mixture, and the iron loss can not be deteriorated. For example, chinese patent CN104404396A published 3, 11/2015 discloses a new method for preparing a new compound₅₀≥1.78T，P_1.5/50The high-magnetic-induction non-oriented silicon steel with the magnetic induction value less than or equal to 5.0W/kg is prepared by adding 0.01-0.15% of Sn + Sb and adjusting the process, reducing the heating temperature of a casting blank to 850-. Chinese patent CN104195427A published 12, 10 and 2014 discloses low-iron-loss high-magnetic-induction non-oriented silicon steelAnd the production method comprises the steps of adding a segregation element Sn, and obtaining a finished product with the iron loss P by a method of finishing rolling at high temperature of not less than 850 ℃ and curling at high temperature of not less than 650 DEG C_1.5/505.10-5.30W/kg, magnetic induction B₅₀₀₀1.77-1.78T, the iron loss value of the silicon steel is higher; chinese patent CN108286021A published in 2018, 7, and 17 discloses a method for preparing a high magnetic induction non-oriented silicon steel plate, which increases texture-beneficial components by compositely adding Sn and Sb, and improves the magnetic property of the non-oriented silicon steel to B₅₀₀₀1.754-1.791T, and iron loss P_1.5/50Less than or equal to 4.4W/kg, and the addition of Sn and Sb increases the production cost.

In the prior art, the magnetic induction of the non-oriented silicon steel can be improved by adding Sn, Sb and Sn/Sb mixture, and the cost is high.

Disclosure of Invention

The invention aims to provide ultrahigh magnetic induction non-oriented silicon steel and a production method thereof.

The invention also aims to provide the application of the ultrahigh magnetic induction non-oriented silicon steel in the production of the automobile generator, and compared with the iron core produced by the conventional product, the iron core of the automobile generator produced by the ultrahigh magnetic induction non-oriented silicon steel produced by the CSP has the advantages that the weight can be reduced by more than 15%, the size of the generator is reduced, and the requirements of miniaturization and high efficiency of the automobile generator are met.

The specific technical scheme of the invention is as follows:

the ultrahigh magnetic induction non-oriented silicon steel comprises the following components in percentage by mass:

c: less than or equal to 0.005%, Si: 0.5-1.2%, Mn: 0.1-0.5%, P: 0.01-0.1%, S: less than or equal to 0.004%, Al: less than or equal to 0.005 percent, N: less than or equal to 0.005 percent, Ti: less than or equal to 0.003 percent, and the balance of iron and inevitable impurities.

The iron loss P of the ultrahigh magnetic induction non-oriented silicon steel_1.5/50≤4.0W/kg，B₅₀₀₀≥1.78T。

C refines the grains. The dispersion distribution of carbide can inhibit the growth of crystal grains, increase hysteresis loss and is not beneficial to the improvement of the magnetic performance of silicon steel, the C content in the silicon steel is reduced as much as possible, but when the C content is less than or equal to 0.005 percent, the further reduction can increase more cost, so the upper limit of the C content of the low-grade silicon steel is 0.005 percent.

Si is beneficial to reducing eddy current loss, but magnetic hysteresis loss can be increased, so that the magnetic induction intensity is reduced, and the content range of Si is set to be 0.5-1.2% by comprehensively considering the iron loss and the magnetic induction intensity.

Al acts similarly to Si, but when the Al content is more than 0.005%, fine oxides are easily formed in the steel to inhibit the growth of crystal grains and deteriorate the magnetic properties, and the upper limit of the Al content is set to 0.005%.

P is an effective element for increasing the resistivity as Al and Si, and P is segregated along the grain boundary, so that the alpha texture strength can be improved, and the gamma texture strength can be reduced. However, a P content of more than 0.1% lowers workability, resulting in phosphorus embrittlement. Therefore, the upper limit of P is defined as 0.1%, the content of P is less than 0.01%, the magnetic performance is not obviously improved, and the lower limit is defined as 0.01%.

Mn is advantageous for reducing eddy current loss, coarsening MnS, increasing grain size, and reducing hysteresis loss as well as Si, and Mn promotes segregation of P, and the Mn content is more than 0.5%, and P embrittlement is increased, so that the Mn content is defined to be 0.1-0.5%.

The invention provides a method for manufacturing ultrahigh magnetic induction non-oriented silicon steel, which adopts a CSP process to produce and manufacture, and comprises smelting and casting;

the smelting and casting specifically comprise the following steps: firstly, molten iron pretreatment is carried out, the molten iron is smelted by a converter, and the molten iron enters into a sheet billet for continuous casting after ladle argon blowing and RH vacuum treatment.

In order to ensure the continuity of continuous casting and reduce the content of impurity elements in the molten steel, silicon is adopted for deoxidation, so that the content of Ti elements is effectively reduced, and the risk of sticking of the molten steel is reduced.

The manufacturing method further includes hot rolling;

the specific technological parameters of the hot rolling are as follows: the heating temperature is 1050-1150 ℃, the finish rolling temperature is 830-900 ℃, and the curling temperature is 650-720 ℃.

After being soaked by a tunnel furnace, the hot rolling enters a 7-stand continuous rolling mill set for rolling, and the rolling process comprises the following steps: the tunnel furnace 1050-.

The manufacturing method further comprises a normalizing treatment, wherein the normalizing treatment is carried out after the hot rolling;

the normalizing treatment is as follows: the hot rolled plate is subjected to normalizing treatment at the normalizing temperature of 900-.

The pickling is carried out by using hydrochloric acid with the concentration of 10-20% and the pickling temperature is 60-100 ℃.

And cold rolling the normalized sheet to obtain a cold-rolled sheet with the target thickness of 0.5 mm.

The manufacturing method also comprises the steps of continuously annealing the cold-rolled sheet; the continuous annealing specifically comprises the following steps: carrying out continuous annealing in a protective atmosphere at the temperature of 800-900 ℃ for 1-4 min; the protective gas is H₂And N₂Mixed gas of (2), H₂The volume proportion of (A) is 25-40%.

The manufacturing method further includes: and (4) after annealing, coating an insulating coating to obtain a high-magnetic-induction non-oriented silicon steel finished product.

By adopting the CSP thin slab continuous casting and rolling process, the casting blank is cooled at a high speed, crystal grains in the columnar crystal area grow from low temperature to a high temperature area, the columnar crystal proportion in the casting blank is increased, the columnar crystal structure has a strong {100} surface texture, and the {100} surface texture has strong heredity, so that the texture components in the finished product are increased, the magnetic induction intensity is improved, the procedures of casting blank transportation and casting blank reheating are reduced, the process is short, and the cost is low.

The ultrahigh magnetic induction non-oriented silicon steel provided by the invention is not only free of noble metal elements and extremely low in cost, but also has excellent magnetic property and iron loss P_1.5/50≤4.0W/kg，B₅₀₀₀High magnetic induction of not less than 1.78T; compared with the iron core produced by the conventional product, the iron core of the automobile generator produced by the ultrahigh magnetic induction non-oriented silicon steel has the advantage that the iron loss is reduced by P_1.5/50About 15.6%, magnetic induction B₅₀₀₀The silicon steel consumption is reduced, the size of the motor is reduced, the weight can be reduced by more than 15%, the size of the generator is reduced, and the requirements of miniaturization and high efficiency of the automobile generator are met。

The iron loss P1.5/50 provided by the invention is less than or equal to 4.0W/kg, B₅₀₀₀High magnetic induction non-oriented silicon steel of 1.78T or more has low iron loss while having high magnetic induction. By C: less than or equal to 0.005%, Si: 0.5-1.2%, Mn: 0.1-0.5%, P: 0.01-0.1%, S: less than or equal to 0.004%, Al: less than or equal to 0.005 percent, N: less than or equal to 0.005 percent, Ti: the steel is designed with the components of less than or equal to 0.003 percent and the balance of iron and inevitable impurities, and the CSP sheet billet continuous casting and rolling process is matched with a normalizing process, so that no noble metal element is added, and the steel has the advantages of short flow, low cost, high magnetic induction and stable performance; the iron core of the automobile generator produced by the invention has the advantages that the weight can be reduced by more than 15% compared with the iron core produced by conventional products, the size of the generator is reduced, and the requirements of miniaturization and high efficiency of the automobile generator are met. Compared with the prior common non-oriented silicon steel with the corresponding grade, the iron loss P_1.5/50The magnetic induction B is reduced by about 0.7W/kg₅₀₀₀The increase is about 0.05T.

Drawings

FIG. 1 is a metallographic structure diagram of a normalized structure obtained in example 6 of the present invention; the crystal grains are completely recrystallized, and are relatively uniform and relatively large in size;

FIG. 2 is a metallographic structure graph after annealing in example 6 of the present invention; the normalized structure is inherited in the annealing process, the grain size is larger, the uniformity is better, and the iron loss P is_1.5/50Decrease;

FIG. 3 is a normalized EBSD weave pattern according to example 6 of the present invention; the normalized sample has stronger {100} favorable texture component and weaker {111} unfavorable texture;

FIG. 4 is a pattern of an EBSD weave after annealing in accordance with example 6 of the present invention; the texture of the annealed sample is mainly {111} unfavorable texture, and due to the genetic effect of the normalized texture, {100} favorable texture strength is enhanced, {111} unfavorable texture strength is reduced, and magnetic induction intensity B₅₀₀₀Increasing;

FIG. 5 is a metallographic structure of an unorthodox sample of comparative example 3 according to the invention; the crystal is completely recrystallized, but a partially deformed structure exists, and compared with example 6, the structure uniformity is poor, and the grain size is small;

FIG. 6 is a metallographic structure diagram after annealing in comparative example 3 of the present invention; compared with the comparative example 6, the grain size of the annealed structure is smaller, and the uniformity is poorer;

FIG. 7 is an EBSD weave pattern of an un-normalized sample of comparative example 3 of the present invention; the texture of the sample is mainly {100} favorable texture, and compared with example 6, the {100} favorable texture is weaker, and the {111} unfavorable texture is stronger;

FIG. 8 is a pattern of an EBSD weave after annealing in comparative example 3 of the present invention; the texture of the sample is mainly {111} unfavorable texture, and compared with example 6, the {100} favorable texture is weaker, and the {111} unfavorable texture is stronger;

the numbers marked 1, 2, 3, 4, 5, 6, 7 in the figure indicate the texture intensity level, the higher the contour line in the figure, the larger the number inwards.

Detailed Description

The present invention will be described with reference to examples.

The invention provides ultrahigh magnetic induction non-oriented silicon steel which comprises the following components in percentage by mass:

c: less than or equal to 0.005%, Si: 0.5-1.2%, Mn: 0.1-0.5%, P: 0.01-0.1%, S: less than or equal to 0.004%, Al: less than or equal to 0.005 percent, N: less than or equal to 0.005 percent, Ti: less than or equal to 0.003 percent, and the balance of iron and inevitable impurities, and reduces the cost and improves the magnetic induction by the CSP sheet billet continuous casting and rolling matched with a normalizing process.

The manufacturing method of the ultrahigh magnetic induction non-oriented silicon steel adopts CSP thin slab continuous casting and rolling, and comprises the following steps:

1) smelting and casting

Firstly, carrying out molten iron pretreatment, smelting by a 120-ton converter, carrying out ladle argon blowing and RH vacuum treatment, and carrying out sheet billet continuous casting, wherein the chemical components comprise the following components in percentage by mass: c: less than or equal to 0.005%, Si: 0.5-1.2%, Mn: 0.1-0.5%, P: 0.01-0.1%, S: less than or equal to 0.004%, Al: less than or equal to 0.005 percent, N: less than or equal to 0.005 percent, Ti: less than or equal to 0.003 percent, and the balance of iron and inevitable impurities;

in order to ensure the continuity of continuous casting, silicon deoxidation is adopted.

2) Hot rolling: after soaking in a tunnel furnace, the steel plate enters a 7-stand continuous rolling mill set for rolling, and the rolling process comprises the following steps: the tunnel furnace 1050-.

3) Normalizing the hot rolled plate at the normalizing temperature of 900-; the acid washing is carried out by using hydrochloric acid with the concentration of 15 percent, and the acid washing temperature is 80 ℃.

4) And cold rolling the normalized sheet to obtain a cold-rolled sheet with the thickness of 0.5 mm.

5) Subjecting the cold-rolled sheet to H protective gas₂And N₂And carrying out continuous annealing in the protective atmosphere of the mixed gas at the temperature of 800-900 ℃ for 1-4min, and finally coating an insulating coating to obtain the high-magnetic-induction non-oriented silicon steel finished product.

The CSP thin slab continuous casting and rolling process is adopted because of short flow, low cost and benefit to improve the magnetic performance.

Examples 1 to 8

The ultrahigh magnetic induction non-oriented silicon steel comprises the following components in percentage by mass: as shown in table 1, the balance not listed in table 1 is Fe and inevitable impurities.

Comparative examples 1 to 3

The non-oriented silicon steel comprises the following components in percentage by mass: as shown in table 1, the balance not listed in table 1 is Fe and inevitable impurities.

TABLE 1 ingredients (wt%) of examples and comparative examples

Examples	C	Si	Mn	P	S	Ti	Al	N
										1	0.0012	0.53	0.13	0.018	0.003	0.0010	0.002	0.002
2	0.0009	0.64	0.25	0.071	0.002	0.0012	0.002	0.005
									3	0.0017	0.83	0.29	0.027	0.002	0.0011	0.001	0.003
4	0.0016	0.67	0.21	0.052	0.003	0.0014	0.002	0.003
									5	0.0008	0.92	0.40	0.063	0.004	0.0015	0.003	0.004
6	0.0019	1.14	0.35	0.080	0.002	0.0017	0.004	0.005
									7	0.0020	1.12	0.47	0.035	0.002	0.0014	0.002	0.003
8	0.0011	0.76	0.28	0.044	0.003	0.0015	0.003	0.004
									Comparative example 1	0.0010	0.48	0.01	0.015	0.002	0.0007	0.005	0.005
Comparative example 2	0.0050	1.30	0.60	0.012	0.003	0.0015	0.004	0.004
									Comparative example 3	0.0015	0.83	0.33	0.040	0.002	0.0017	0.003	0.002

The method for manufacturing the ultrahigh-magnetic-induction non-oriented silicon steel in the embodiment 1 comprises the following steps:

1) smelting and casting

Firstly, molten iron pretreatment is carried out, the molten iron is smelted by a 120-ton converter, the molten iron enters a sheet billet for continuous casting through ladle argon blowing and RH vacuum treatment, and silicon deoxidation is adopted to ensure the continuity of the continuous casting;

2) hot rolling: after soaking in a tunnel furnace, the steel plate enters a 7-stand continuous rolling mill set for rolling, and the rolling process comprises the following steps: heating in a tunnel furnace at 1120 ℃, wherein the finishing temperature is 875 ℃ and the curling temperature is 700 ℃;

3) normalizing the hot rolled plate at the normalizing temperature of 940 ℃ for 100s, and then carrying out acid pickling with hydrochloric acid with the concentration of 15% at the pickling temperature of 80 ℃ to obtain a normalized plate;

4) cold rolling the normalized sheet to obtain a cold-rolled sheet with the thickness of 0.5 mm;

5) placing the cold-rolled sheet in H₂And N₂Mixed gas (H) of (2)₂25%) as protective atmosphere, carrying out continuous annealing at 880 ℃ for 150s, and finally coating an insulating coating to obtain the finished product of the high-magnetic-induction non-oriented silicon steel.

Examples and comparative examples were manufactured in the same manner as in example 1 above, except that the process parameters were changed, and specific process parameters were manufactured as shown in table 2.

TABLE 2 Main Process parameters and Performance profiles for the examples and comparative examples

Comparing the metallographic structure diagram and the EBSD structure diagram of example 6 and comparative example 3, FIG. 1 shows that after normalizing, example 6 has been completely recrystallized, the crystal grains are more uniform, and the crystal grain size is larger; FIG. 2 shows that the normalized structure is inherited during annealing, the grain size is large, the uniformity is good, and the iron loss P is high_1.5/50Decrease; FIG. 3 shows that the normalized sample has a strong {100} favorable texture component and a weak {111} unfavorable texture;

FIG. 4 shows that the texture of the annealed sample is mainly {111} unfavorable texture, and due to the genetic effect of the normalized texture, {100} favorable texture intensity is enhanced, {111} unfavorable texture intensity is reduced, and magnetic induction intensity B is₅₀₀₀And (4) improving. In contrast, in comparative example 3, the structure reflected in fig. 5 was completely recrystallized after normalization, but a partially deformed structure existed, and compared with example 6, the structure uniformity was inferior and the grain size was smaller; FIG. 6 reflects that the grain size of the annealed structure of comparative example 3 is smaller and the uniformity is poorer; FIG. 7 reflects the texture predominates in the comparative example 3 sample as {100} favored texture, with {100} favored texture being weaker and {111} unfavorable texture being stronger than in example 6; FIG. 8 shows that the texture of the sample is dominated by the {111} unfavorable texture, and that the {100} favorable texture is weaker and the {111} unfavorable texture is stronger than that of example 6.

As can be seen from Table 2, the present invention can significantly improve the magnetic properties of non-oriented silicon steel by the CSP thin slab continuous casting and rolling normalizing process. The iron loss and the magnetic induction of the above examples both meet the requirements of iron loss P1.5/50 less than or equal to 4.0W/kg and B5000 more than or equal to 1.78T, while the comparative example 3 has no normalizing treatment, and the iron loss and the magnetic induction are obviously poorer.

Claims

1. The ultrahigh magnetic induction non-oriented silicon steel is characterized by comprising the following components in percentage by mass:

2. The ultra-high magnetic induction non-oriented silicon steel as claimed in claim 1, wherein the iron loss P of the ultra-high magnetic induction non-oriented silicon steel_1.5/50≤4.0W/kg，B₅₀₀₀≥1.78T。

3. The method for manufacturing the ultrahigh magnetic induction non-oriented silicon steel as claimed in claim 1 or 2, characterized by adopting a CSP process.

4. The manufacturing method according to claim 3, wherein the smelting and casting are specifically: firstly, molten iron pretreatment is carried out, the molten iron is smelted by a converter, and the molten iron enters into a sheet billet for continuous casting after ladle argon blowing and RH vacuum treatment.

5. The manufacturing method according to claim 3 or 4, characterized in that the manufacturing method comprises hot rolling;

6. The method according to any one of claims 3 to 5, wherein the hot rolling is followed by a normalizing treatment at 900 ℃ and 1000 ℃ for 1 to 3 min.

7. The method according to claim 6, wherein the acid washing is carried out after the normalization, and the acid washing is carried out using hydrochloric acid having a concentration of 10 to 20% and has a temperature of 60 to 100 ℃.

8. The manufacturing method according to claim 6 or 7, characterized by further comprising a continuous annealing, the cold-rolled sheet being subjected to the continuous annealing; the continuous annealing specifically comprises the following steps: and carrying out continuous annealing in a protective atmosphere at the temperature of 800-900 ℃ for 1-4 min.

9. The method of manufacturing according to claim 8, wherein the shielding gas is H₂And N₂Mixed gas of (2), H₂The volume proportion of (A) is 25-40%.

10. Use of the ultrahigh-magnetic-induction non-oriented silicon steel of claim 1 or 2 in the production of automobile generators.