Cold-rolled oriented electrical steel strip for YE4-grade motor and manufacturing method of cold-rolled oriented electrical steel strip

Abstract

The invention discloses a cold-rolled oriented electrical steel strip for a YE4-grade motor and a manufacturing method of the cold-rolled oriented electrical steel strip, and relates to the technical field of cold-rolled oriented electrical steel strips. The cold-rolled oriented electrical steel strip comprises the following chemical components in percentage by weight: 0.02 to 0.08 percent of C, 2.5 to 3.2 percent of Si, 0.10 to 0.50 percent of Mn, less than or equal to 0.02 percent of P, 0.05 to 0.15 percent of Als, 0.10 to 0.50 percent of Cu, 0.05 to 0.15 percent of Re, 0.05 to 0.15 percent of Sb, 0.005 to 0.015 percent of S, 0.005 to 0.015 percent of N, less than or equal to 0.004 percent of Ti and the balance of Fe and inevitable impurities. The manufacturing method comprises the following steps: continuously casting molten steel into a plate blank, heating, carrying out hot rolling, carrying out normalizing pickling, carrying out cold rolling, carrying out decarburization annealing, coating an MgO separant, carrying out cover type high-temperature annealing, stretching and flattening, and coating an insulating coating. The cold-rolled oriented electrical steel strip for the YE4-grade motor has the advantages of being high in magnetic induction intensity and low in iron loss, is used for producing the YE4-grade motor, has the advantages of being high in energy efficiency and low in noise, and can meet the requirements of YE4 motor manufacturing high-end users for the energy efficiency grade and the noise grade.

Description

Technical Field

[0001] The present invention relates to the technical field of cold-rolled grain-oriented electrical steel strips, and particularly to a cold-rolled grain-oriented electrical steel strip for YE4-class motors and a manufacturing method thereof. Background Art

[0002] With the increasingly severe global energy crisis and environmental problems, the improvement of motor energy efficiency has become an important issue in the industrial field. As a power device widely used in industrial production and daily life, the energy efficiency level of motors directly affects energy consumption and carbon emissions. The International Electrotechnical Commission (IEC) and national energy efficiency standards have put forward strict requirements for the energy efficiency grades of motors. Among them, as a super-high energy efficiency motor, the design and manufacturing of YE4-class motors pose higher challenges to the material properties. As the core component of the motor, the material properties of the motor core directly determine the energy efficiency, noise and operating stability of the motor.

[0003] Currently, cold-rolled non-oriented silicon steel sheets are usually used as raw materials for manufacturing motor cores. Cold-rolled non-oriented silicon steel sheets have high magnetic induction intensity, low iron loss, and very small differences in magnetic permeability in all directions. These properties have made them widely used in motor manufacturing. For example, the Chinese invention patent with the application number 202011001875.5 discloses a non-oriented silicon steel sheet for servo motors and its production method, providing a non-oriented silicon steel product with low iron loss and high magnetic induction specifically for servo motors and its production method. However, with the continuous improvement of motor performance requirements, the defects of cold-rolled non-oriented silicon steel sheets, such as insufficient magnetic induction intensity, too high iron loss, high noise, etc., limit their further development in the field of YE4-class motors. Summary of the Invention

[0004] To overcome the deficiencies of the above technologies, the purpose of the present invention is to provide a cold-rolled grain-oriented electrical steel strip for YE4-class motors and a manufacturing method thereof, so as to solve the problems of insufficient magnetic induction intensity, high iron loss, and high noise in existing materials.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A cold-rolled grain-oriented electrical steel strip for YE4-class motors, characterized in that it includes the following chemical components by weight percentage: Re 0.05 - 0.15, Sb 0.05 - 0.15.

[0007] As a preferred embodiment, the cold-rolled grain-oriented electrical steel strip comprises the following chemical components by weight percentage: C 0.02 - 0.08, Si 2.5 - 3.2, Mn 0.10 - 0.50, P ≤ 0.02, Als 0.05 - 0.15, Cu 0.10 - 0.50, Re 0.05 - 0.15, Sb 0.05 - 0.15, S 0.005 - 0.015, N 0.005 - 0.015, Ti ≤ 0.004, and the balance is Fe and inevitable impurities.

[0008] The present invention also provides a manufacturing method of the cold-rolled grain-oriented electrical steel strip for YE4 grade motors as described above, which is characterized in that it includes the following steps: continuous casting, heating, hot rolling, normalizing and pickling, cold rolling, decarburizing annealing, MgO separator coating, box-type high-temperature annealing, skin pass rolling, and insulating coating; wherein, the slab obtained by continuous casting has a thickness of 60 - 70 mm; the slab directly enters the heating furnace for heating after continuous casting, the heating temperature is 1150 - 1250 °C, and the heating time is not less than 1.0 h; the thickness of the steel strip is 0.15 mm - 0.30 mm.

[0009] As a preferred embodiment, during the hot rolling process, the finish rolling temperature is 900 - 1000 °C, and the coiling temperature is 500 - 600 °C.

[0010] Furthermore, during the hot rolling process, the thickness of the hot rolled sheet is 2.0 - 2.5 mm.

[0011] As a preferred embodiment, during the normalizing and pickling process, the normalizing temperature is 1000 - 1100 °C, and the pickling temperature is 70 - 90 °C.

[0012] As a preferred embodiment, the cold rolling is carried out in 5 - 6 passes; the thickness of the cold rolled sheet after cold rolling is 0.15 - 0.30 mm.

[0013] As a preferred embodiment, during the decarburizing annealing process, the annealing temperature is 800 - 900 °C, the holding time is 2 - 4 min, the protective gas is a nitrogen-hydrogen mixed gas, and the furnace dew point is controlled at 20 - 30 °C; in the nitrogen-hydrogen mixed gas, the volume percentage content of hydrogen is 20 - 30%.

[0014] As a preferred embodiment, during the MgO separator coating process, the drying temperature is 450 - 550 °C.

[0015] As a preferred embodiment, during the box-type high-temperature annealing process, the annealing temperature is 1100 - 1250 °C, the holding time is 24 - 36 h; the protective gas is a nitrogen-hydrogen mixed gas or hydrogen; in the protective gas, the volume percentage content of hydrogen is 20 - 100%, and when the furnace temperature of the box-type high-temperature annealing furnace is higher than 750 °C, full hydrogen protection is adopted.

[0016] As a preferred solution, the stretching and leveling process is carried out on a leveling machine; the insulation coating is applied through a coating unit, and the curing temperature of the coating is 300 - 450 °C.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] A cold-rolled grain-oriented electrical steel strip for YE4-class motors of the present invention has the advantages of high magnetic induction intensity and low iron loss. It is used to produce YE4-class motors, which have the advantages of high energy efficiency and low noise, and can meet the requirements of high-end users of YE4 motor manufacturing for energy efficiency grades and noise levels. The cold-rolled grain-oriented electrical steel strip of the present invention is made by adding Re element and Sb element to control the material structure and adopting specific process methods such as thin slab continuous casting and rolling. The finished product iron loss P of the grain-oriented electrical steel strip with a thickness of 0.15 mm - 0.30 mm 1.7 / 50 ≤1.00 W / kg, B8≥1.94 T. Specific embodiments

[0019] To better explain the present invention, the main content of the present invention is further clarified below in conjunction with specific embodiments, but the content of the present invention is not limited to the following embodiments.

[0020] Example 1

[0021] A manufacturing method of a cold-rolled grain-oriented electrical steel strip for YE4-class motors includes the following steps: continuously casting molten steel into a slab with a thickness of 62 mm, directly feeding the slab into a heating furnace for heating and heat preservation, the temperature of the heating furnace is 1220 °C, and the heating time is 1.5 h; rolling it into a hot-rolled sheet with a thickness of 2.2 mm through seven-stand continuous rolling; making the hot-rolled sheet into a finished product of a grain-oriented electrical steel strip with a thickness of 0.20 mm through normalizing pickling, cold rolling, decarburizing annealing, MgO separating agent coating, batch annealing at high temperature, stretching and leveling, and insulation coating.

[0022] The chemical composition of the slab in weight percentage is C: 0.040, Si: 2.80, Mn: 0.25, P: 0.010, Als: 0.09, Cu: 0.38, Re: 0.07, Sb: 0.06, S: 0.008, N: 0.013, Ti: 0.0014, and the rest is Fe and inevitable impurities.

[0023] The final rolling temperature of hot rolling is 950 °C, and the coiling temperature is 560 °C; normalizing and pickling are carried out on the normalizing and pickling line, the normalizing temperature is 1050 °C, and the pickling temperature is 80 °C; cold rolling is carried out on a 6-high reversing mill and cold rolled to a thickness of 0.2 mm in 6 passes; decarburizing annealing is carried out in a continuous annealing furnace, the annealing temperature is 850 °C, the holding time is 3 min, protected by a nitrogen-hydrogen mixed gas, the hydrogen content is 25% by volume, and the dew point in the furnace is controlled at 25 °C; coating with MgO release agent is carried out on a continuous coating unit, and the drying temperature is 520 °C; box-type high-temperature annealing is carried out in a box-type annealing furnace, the annealing temperature is 1200 °C, the holding time is 30 h, protected by a nitrogen-hydrogen mixed gas, the hydrogen content is 50% by volume, and when the furnace temperature is higher than 750 °C, full-hydrogen gas protection is adopted; skin pass rolling is carried out on a skin pass mill; insulation coating is carried out on a coating unit, and the coating curing temperature is 380 °C;

[0024] The cold-rolled grain-oriented electrical steel strip manufactured by the above process has a finished core loss P 1.7 / 50 of 0.98 W / kg and a magnetic induction B8 of 1.95 T. The energy efficiency grade and noise level of the motor manufactured from the steel strip can meet the requirements of high-end users for YE4 motor manufacturing.

[0025] Example 2

[0026] A manufacturing method of a cold-rolled grain-oriented electrical steel strip for YE4 grade motors. Molten steel is continuously cast into a slab with a thickness of 67 mm, and the slab directly enters a heating furnace for heating and holding. The temperature of the heating furnace is 1180 °C, and the heating time is 2.0 h; it is rolled into a hot-rolled sheet with a thickness of 2.5 mm through a seven-stand continuous rolling mill; the hot-rolled sheet is made into a finished grain-oriented electrical steel strip with a thickness of 0.17 mm through normalizing and pickling, cold rolling, decarburizing annealing, MgO release agent coating, box-type high-temperature annealing, skin pass rolling, and insulation coating.

[0027] The chemical composition of the slab by weight percentage is C: 0.060, Si: 3.00, Mn: 0.34, P: 0.008, Als: 0.12, Cu: 0.22, Re: 0.08, Sb: 0.12, S: 0.012, N: 0.008, Ti: 0.0012, and the rest is Fe and unavoidable impurities.

[0028] The final rolling temperature of hot rolling is 970 °C, and the coiling temperature is 575 °C; normalizing and pickling are carried out on the normalizing and pickling line, the normalizing temperature is 1050 °C, and the pickling temperature is 80 °C; cold rolling is carried out on a 6-high reversible mill and cold rolled to a thickness of 0.17 mm after 6 passes; decarburizing annealing is carried out in a continuous annealing furnace, the annealing temperature is 870 °C, the holding time is 3 min, protected by a nitrogen-hydrogen mixed gas, the hydrogen content is 25% by volume, and the furnace dew point is controlled at 25 °C; coating with MgO separating agent is carried out on a continuous coating unit, and the drying temperature is 520 °C; box-type high-temperature annealing is carried out in a box-type annealing furnace, the annealing temperature is 1200 °C, the holding time is 30 h, protected by a nitrogen-hydrogen mixed gas, the hydrogen content is 50% by volume, and when the furnace temperature is higher than 750 °C, full-hydrogen gas protection is adopted; skin pass rolling is carried out on a skin pass mill; insulating coating is carried out on a coating unit, and the coating curing temperature is 420 °C.

[0029] The cold-rolled grain-oriented electrical steel strip manufactured by the above process has a finished core loss P 1.7 / 50 of 0.95 W / kg and a magnetic induction B8 of 1.96 T. The energy efficiency grade and noise level of the motor manufactured from the steel strip can meet the requirements of high-end users for YE4 motor manufacturing.

[0030] Other parts not described belong to the prior art.

Claims

1. A cold-rolled oriented electrical steel strip for YE4 grade motor, characterized by: The invention comprises the following chemical components in percentage by weight: Re 0.05-0.15, Sb 0.05-0.

15.

2. The YE4 grade cold-rolled oriented electrical steel strip for motors according to claim 1, characterized in that: The cold-rolled oriented electrical steel strip comprises the following chemical components in weight percentage: C 0.02-0.08, Si 2.5-3.2, Mn 0.10-0.50, P≤0.02, Als 0.05-0.15, Cu 0.10-0.50, Re 0.05-0.15, Sb 0.05-0.15, S 0.005-0.015, N 0.005-0.015, Ti≤0.004, and the rest are Fe and unavoidable impurities.

3. A method for manufacturing the YE4 grade cold-rolled oriented electrical steel strip for motors according to claim 1 or 2, characterized in that: The following steps are involved: Continuous casting, heating, hot rolling, normalizing pickling, cold rolling, decarburization annealing, MgO isolation agent coating, hood high temperature annealing, stretching and flattening, and insulating coating coating; wherein the slab thickness obtained by continuous casting is 60-70 mm; after continuous casting, the slab directly enters the heating furnace for heating, the heating temperature is 1150-1250°C, and the heating time is not less than 1.0 h; the thickness of the steel strip is 0.15 mm-0.30 mm.

4. The manufacturing method according to claim 3, characterized in that: During the hot rolling process, the final rolling temperature is 900-1000°C, and the coiling temperature is 500-600°C.

5. The manufacturing method according to claim 3, characterized in that: In the normalizing pickling process, the normalizing temperature is 1000-1100°C and the pickling temperature is 70-90°C.

6. The manufacturing method according to claim 3, characterized in that: The cold rolling is performed in 5 to 6 passes; the thickness of the cold rolled plate after cold rolling is 0.15 to 0.30 mm.

7. The manufacturing method according to claim 3, characterized in that: During the decarburization annealing process, the annealing temperature is 800-900°C, the holding time is 2-4 minutes, the protective gas is a nitrogen-hydrogen mixed gas, and the dew point in the furnace is controlled at 20-30°C; the volume percentage of hydrogen in the nitrogen-hydrogen mixed gas is 20-30%.

8. The manufacturing method according to claim 3, characterized in that: During the coating process of the MgO separator, the drying temperature is 450-550°C.

9. The manufacturing method according to claim 3, characterized in that: During the hood-type high-temperature annealing process, the annealing temperature is 1100-1250°C, and the holding time is 24-36 hours; the protective gas is a nitrogen-hydrogen mixed gas or hydrogen; the volume percentage of hydrogen in the protective gas is 20-100%, and when the temperature of the annealing furnace for hood-type high-temperature annealing is higher than 750°C, full hydrogen protection is adopted.

10. The manufacturing method according to any one of claims 3 to 9, characterized in that: The stretching and leveling process is carried out on a leveling machine; the insulating coating is applied by a coating unit, and the curing temperature of the coating is 300-450°C.