Want to know why silicon steel is used for BLDC motor lamination? What magical properties does this humble material have that make it a “victorious general” in motor stator and rotor design?
Different silicon steel materials have unique compositions and characteristics that directly affect the efficiency and performance of the motor. In this article, we will take a deep look at several commonly used silicon steel materials for brushless motor stator and rotor laminations.
What Is Silicon Steel?
Silicon steel, also known as electrical steel, laminated steel or transformer steel. It is mainly composed of iron, silicon and carbon, and the silicon content is usually between 0.8% and 6.5%. Due to its low core loss and high magnetic permeability, it is an important material for manufacturing brushless motor laminations.
So what kind of silicon steel is used for the rotor and stator cores of brushless motors?
Whether outer rotor or inner rotor brushless motor core, the commonly used material is 0.1mm – 0.65mm non-oriented electrical steels.
How is the grade of silicon steel material used in brushless motors expressed?
Silicon Steel Material Grade Representation Method
Let’s take Baosteel’s grades as an example. B35AH230 represents high-efficiency non-oriented silicon steel with a nominal thickness of 0.35mm, and the maximum nominal value of total loss P1.5/50 is 2.30W/kg. B35A210 represents ordinary non-oriented silicon steel with a nominal thickness of 0.35mm, and the maximum nominal value of total loss P1.5/50 is 2.10W/kg.
Let’s take a look at the composition and performance of silicon steel lamination materials commonly used in brushless motors.
Commonly Used Silicon Steel Materials For Brushless Motor Cores
USWH35080H (10SW1000)
USWH35080H refers to 0.1mm thick non-oriented electrical steel, with a density of 7.6KG/dm³. Lamination stacking factor≥94%, and magnetic polarization of 1.65T. Due to its extremely thin, high magnetic induction and high strength characteristics, it is widely used in brushless stators of ultra-high-speed motors such as fuel cell air compressors and electric spindles.
How strong is the magnetic performance of the USWH35080H used in brushless motor core lamination, and what is the iron loss that can be achieved? Is this closer to what you were looking for? Please see the table below.
| Material Grade | Density (kg/dm³) | Iron loss P1.0/400（W/KG） | Lamination Stacking Factor(%) | Magnetic PolarizationJ5000(T) |
| USWH35080H | 7.6 | 10 | ＞94 | 1.65 |
15SW1200
15SW1200 refers to 0.15mm thick cold-rolled non-oriented electrical steel with a density of 7.65KG/dm³. Lamination stacking factor of ＞97%, and a magnetic polarization of 1.61T.
This silicon steel has low iron loss and high magnetic induction intensity, high strength and toughness, and is easy to process and form.
15SW1200 is suitable for brushless motor stators of electric vehicle drive motors, brushless water pump motor cores, and other high-performance motor cores.
| Material Grade | Density (kg/dm³) | Iron loss P1.0/400（W/KG） | Lamination Stacking Factor(%) | Magnetic PolarizationJ5000(T) |
| 15SW1200 | 7.65 | 11 | ＞97 | ＞1.61 |
B20AV1200
B20AV1200 refers to non-oriented electrical steel with a thickness of 0.2mm, density of 7.6KG/dm³. Lamination stacking factor of about 98%, and magnetic polarization of 1.62T.
Its main characteristics are low loss, high magnetic permeability, high magnetic induction, high magnetic flux density, excellent processing performance, excellent stamping performance and excellent corrosion resistance.
B20AV1200 silicon steel is apply to the stator of brushless motors for drones, the iron core of brushless motors for electric vehicles, and the iron core of brushless hub motors.
How strong is the magnetic performance of B20AV1200 and how much iron loss can it reach? Please see the figure below.
| Material Grade | Density (kg/dm³) | Iron loss P1.0/400（W/KG） | Lamination Stacking Factor(%) | Magnetic PolarizationJ5000(T) |
| B20AV1200 | 7.65 | 11.62 | ＞97.5 | 1.62 |
25SW1300
25SW1300 refers to non-oriented electrical steel with a thickness of 0.25mm, density of 7.6KG/dm³. Lamination stacking factor of >95%. Under the condition of P15/50, the iron loss value is 2.11w/kg, and under the condition of P1.0/400, the iron loss value is 13w/kg. Under the condition of 5000A/m, the magnetic polarization is 1.65T.
25SW1300 is an electrical steel with low iron loss and high magnetic properties, which is suitable for new energy motor lamination core.
| Material Grade | Density (kg/dm³) | Iron loss P1.0/400（W/KG） | Lamination Stacking Factor(%) | Magnetic PolarizationJ5000(T) |
| 25SW1300 | 7.6 | 13 | ＞95 | 1.65 |
27SW1400
27SW1400 refers to non-oriented electrical steel with a thickness of 0.27mm, a density of 7.6KG/dm³, and a lamination stacking factor of >98.5%. Under the condition of P1.0/400, the iron loss value is 12.7w/kg. Under the condition of 5000A/m, the magnetic polarization is 1.64T.
| Material Grade | Density (kg/dm³) | Iron loss P1.0/400（W/KG） | Lamination Stacking Factor(%) | Magnetic PolarizationJ5000(T) |
| 27SW1400 | 7.6 | 12.7 | ＞98.5 | 1.64 |
Z coating is an organic component with high interlayer resistance and can greatly improve the punching performance of steel strips, making it very suitable for punching and cutting laminations. After heating and curing under pressure holding conditions, bonded the laminations together to form a stator or rotor core.
27SW1400-Z is the first choice for gluing brushless motor cores. Compared with Baosteel’s materials, this material has better temperature resistance.
B35A250
B35A250 refers to non-oriented electrical steel with a thickness of 0.35mm, a density of 7.6KG/dm³, and lamination stacking factor of >96.7%. Under the condition of P1.0/50, the iron loss value is 1.06w/kg. Under the condition of 5000A/m, the magnetic polarization is 1.66T.
| Material Grade | Density (kg/dm³) | Iron loss P1.0/50（W/KG） | Lamination Stacking Factor(%) | Magnetic PolarizationJ5000(T) |
| B35A250 | 7.6 | 1.06 | ＞96.7 | 1.66 |
B35A250 is suitable for manufacturing micro and small brushless motor cores, which can enhance the filling factor. In addition, the material has good heat resistance and weldability, and is also suitable for axial flux motor stators.
B50A400
B50A400 refers to non-oriented electrical steel with a thickness of 0.5mm, density of 7.7KG/dm³, and lamination stacking factor of >96%. Under the condition of P1.0/50, the iron loss value is 1.30w/kg. Under the condition of 5000A/m, the magnetic polarization is 1.7T.
| Material Grade | Density (kg/dm³) | Iron loss P1.0/50（W/KG） | Lamination Stacking Factor(%) | Magnetic PolarizationJ5000(T) |
| B50A400 | 7.7 | 1.30 | ＞96 | 1.7 |
B50A400 electrical steel is a high-performance magnetic material that can reduce induction current loss and improve motor efficiency. It is usually suitable for large brushless motor cores, such as wind turbines, elevator traction machines, large water pumps, etc.
There are many cold-rolled silicon steel grades apply to the manufacture of brushless motor rotor and stator laminations at home and abroad. Please see the table below.
Domestic Silicon Steel Is Used For BLDC Motor Lamination
| China Steel | Sweden Hi-Lite | Japan Steel | |
| 0.1mm | 10SW1000 10HWA900 | NO10-1270N | 10JNEX900 10JNHF600 ST-100 |
| 0.15mm | B15AT1200 B15AV1000 15SW1200 15WTG1500 15CS1200 | NO15-1230N NO15-1100H | ST-150 |
| 0.2mm | B20AT1200 B20AT1500 20SW1200 20SW1500 20TWV1200 20CS1200 20CS1500 20ZW1200 | NO20-1350N NO20-1100H NO20-1200H NO20-1300H | 20JNEH1200 20JNEH1500 |
| 0.25mm | B25AHV1300 B25AV1300 25SW1250 25SW1300 25TWV1300 | NO25-1350H | |
| 0.27mm | B27AV1400 B27AHV1400 B27APV1400 27SW1400 27SWH1400 27SWG1400 27SW1400H 27TWV1400 | NO27-1400H | |
| 0.30mm | B30AV1500 B30AHV1500 B30APV1500 30SW1500 30SWH1500 30SWG1500 30SW1500H | NO30-1500H | 30JNE230 |
| 0.35mm | B35A210 B35A230 B35A250 B35A270 B35A300 B35AV1900 B35AV2100 B35AHV1700 B35AHV1900 B35APV1700 B35APV1900 35SW1700 35SW1700 35SWH1900 35SWG1700 35SWYS500 35SWYS900 35SW1700H 35W230 35W250 35W270 35W300 35W360 35W400 35W440 | NO35-1750H | 35JNE250 |
| 0.50mm | B50A270/290/350/470/600/800 50W230/250/270/290/310/330/350/ 400/470/540/600/700/800/1000/1300 50SW400 50TW400 | 50JNE470 |
Silicon steel sheets are the “invisible heroes” of brushless motor cores. Whether it is electric cars or drones, they cannot do without their support. If you also need brushless motor stator and rotor cores made of silicon steel sheets, please feel free to contact us.
FAQ
How To Classify Silicon Steel For Motor Core?
Silicon steel sheets can be divided into cold-rolled steel and hot-rolled steel according to the production process, among which cold-rolled steel is further divided into oriented steel and non-oriented steel. According to the silicon content, it is divided into low silicon steel and high silicon steel. The silicon content of low silicon steel is less than 2.8%, while the silicon content of high silicon steel is between 2.8%-6.5%.
Which Materials Are Commonly Used In The Manufacture Of Brushless Motor Cores?
In addition to non-oriented electrical steel, there are also 0.2mm-0.5mm thick cobalt-iron alloys, nickel-iron alloys, and 0.025mm amorphous alloys widely used in the production of brushless DC motor cores. Due to the high cost of materials, they are currently only used in the proofing stage, and these materials are rarely used in mass production.
