Non-oriented silicon steel sheet, also known as cold-rolled non-oriented electrical steel, is a low-silicon iron-based soft magnetic alloy with a random grain orientation after deformation and annealing, containing 0.8%–4.8% silicon. It is an indispensable magnetic material in the power, electronics, industrial, and new energy vehicle sectors. Zhongxin Steel supplies high-quality electrical steel that meets GB/T 2521–2008, EN 10341, ASTM A876, JIS C2552, and IEC 60404, and has provided premium electrical steel materials for various motor core manufacturers around the world.
Production Process of Non-Oriented Silicon Steel Sheet
The production process of non-oriented silicon steel sheet mainly involves a series of steps, including pre-desulfurization of molten iron, converter steelmaking, vacuum decarburization, continuous casting, hot rolling, normalizing, pickling, cold rolling, annealing, and insulating coating. This process enables high-precision rolling of ultra-thin specifications, such as 0.2mm or even 0.1mm, and meets the demand for thin-gauge, high-grade products in fields such as new energy vehicles and variable frequency compressors.
Substrate of Non-Oriented Silicon Steel Sheet
The magnetic performance of the substrate is a core indicator of non-oriented silicon steel and determines the energy efficiency level of motor cores. Different application scenarios have different requirements for core loss, magnetic flux density, and mechanical properties:
- Mid-to-low grade non-oriented silicon steel (e.g., 35W440, 50W470, 50W600, 50W800) offers moderate magnetic properties and good processability, with core loss values between 4.0–8.0 W/kg and magnetic flux density around 1.65–1.73 T.
- High-grade non-oriented silicon steel (e.g., 35W300, 50W350, 65W310, etc.) has significantly lower core loss (P1.5/50 ≤ 3.00–3.50 W/kg) while maintaining high magnetic flux density.
- Very high grade / thin-gauge non-oriented silicon steel (e.g., B10AHV900M, B50AM250, etc., thickness down to 0.1 mm, minimum core loss below 9 W/kg).
Chemical Composition of Non-Oriented Silicon Steel
The chemical composition of non-oriented silicon steel is a key factor affecting its magnetic and processing properties. The matrix is iron-based, with appropriate amounts of silicon, aluminum, and other alloying elements, and strictly controlled levels of impurities such as carbon and sulfur.
Matrix composition range (wt%)
| Element | Content Range |
| Si | 0.8% – 3.5% |
| Al | 0.1% – 1.0% |
| Mn | 0.15% – 0.80% |
| C | ≤ 0.005% |
| S | ≤ 0.003% |
| P | ≤ 0.035% |
Surface Insulation Coating
Non-oriented silicon steel is coated with an insulating layer to prevent eddy current losses between laminations. The coating resistivity is generally ≥50 Ω·cm². Main coating types include inorganic coating D (good heat resistance and weldability), semi-organic thin coating A (improved punchability and good weldability), semi-organic thick coating H (good punchability and high interlayer resistance), chromium-free coating K (environmentally friendly, not included hexavalent chromium), and self-adhesive coating Z (high core fixing strength).
Magnetic Properties of Non-Oriented Silicon Steel Sheet
The magnetic properties of non-oriented silicon steel are core indicators of quality, mainly including core loss (P) and magnetic flux density (B).
- Core loss (P): The energy consumed per unit weight of silicon steel during magnetization, expressed in W/kg. It is measured under power frequency 50 Hz and magnetic flux density 1.5 T (denoted P1.5/50). Lower core loss means higher motor efficiency and lower temperature rise.
- Magnetic flux density (B): The magnetic induction intensity of silicon steel under a specific magnetic field strength, expressed in Tesla (T). Typically B50 (magnetic flux density at 5000 A/m) or B25 (at 2500 A/m) is measured. Higher magnetic flux density enables higher output power density and smaller motor size.
Typical magnetic property values of common grades (50 Hz, 1.5 T)
| Thickness (mm) | Grade | Max. core loss P1.5/50 (W/kg) | Min. magnetic flux density B50 (T) | Min. lamination factor (%) |
| 0.35 | 35W300 | ≤3.00 | ≥1.62 | ≥97.0 |
| 0.50 | 50W470 | ≤4.70 | ≥1.65 | ≥97.0 |
| 0.50 | 50W600 | ≤6.00 | ≥1.67 | ≥97.0 |
| 0.50 | 50W800 | ≤8.00 | ≥1.70 | ≥97.0 |
| 0.65 | 65W600 | ≤6.00 | ≥1.65 | ≥97.0 |
| 0.65 | 65W1300 | ≤13.00 | ≥1.70 | ≥97.0 |
Thickness and Dimensional Specifications of Non-Oriented Silicon Steel
Non-oriented silicon steel is supplied in coil form, with typical thicknesses of 0.20 mm, 0.35 mm, 0.50 mm, 0.65 mm, etc. Zhongxin Steel can process coils into various widths or cut-to-length sheets according to customer requirements.
Standard thicknesses and tolerances
| Nominal thickness (mm) | Common grades | Thickness tolerance (mm) | Main application areas |
| 0.20 | 20WV1200, 25AGW270 | ±0.02 | New energy vehicles, high-frequency motors |
| 0.35 | 35W300, 35W440 | ±0.02–0.03 | High-efficiency industrial motors, variable-frequency compressors |
| 0.50 | 50W470, 50W600, 50W800 | ±0.03–0.05 | Medium/large motors, household appliance motors |
| 0.65 | 65W600, 65W800, 65W1300 | ±0.03–0.05 | General industrial motors, generators |
- Width and coil weight: Available width range is 600–1300 mm (or wider, can be slit into different widths). Coil inner diameters are mostly φ508 mm or φ610 mm, suitable for various uncoiling and stamping lines. Maximum coil weight is generally 15–25 tons.
- Cut sheet dimensions: Can be processed into specific lengths (e.g., 1000 mm, 2000 mm) for laminated core manufacturing.
- Weight calculation formula: Steel weight (kg) = thickness (mm) × width (m) × length (m) × 7.85 (carbon steel density ~7.85 g/cm³; for silicon steel, density varies slightly with silicon content, typically 7.60–7.85 is used).
Raw Material (Non-Oriented Silicon Steel Coil)
Non-oriented silicon steel is produced from hot-rolled silicon steel coils through cold rolling, recrystallization annealing, coating, and other processes.
| Parameter | Details |
| Thickness | 0.20–0.80 mm (standard); 0.10–0.20 mm (thin gauge) |
| Width | 600–1300 mm (customizable rolling width and slitting) |
| Coil inner diameter | Φ508 mm / Φ610 mm (compatible with uncoiling lines) |
| Coil outer diameter | 1200–2000 mm (depending on coil weight and thickness) |
| Coil weight | 15–25 tons (customizable) |
| Insulation coating | Inorganic D / Semi-organic thin A / Semi-organic thick H / Chromium-free K / Self-adhesive Z |
| Quality certification | Compliant with GB/T 2521, ISO 9001, IATF 16949 (new energy vehicle industry) |
| Storage requirements | Moisture-proof, dust-proof, avoid mechanical damage, keep flat stacking |
Finished Products of Non-Oriented Silicon Steel
Zhongxin Steel’s non-oriented silicon steel coils can be further processed by slitting, cross-cutting, stamping, and lamination to produce various core forms.
Motor Stator and Rotor Core Laminations
Non-oriented silicon steel coils are stamped in one operation to produce stator and rotor laminations. Medium/small motor cores mainly use 0.35 mm and 0.50 mm thicknesses, while large motors and generators use 0.50 mm and 0.65 mm. After stamping, laminations are stacked, pressed, welded, or self-bonded to form complete motor core assemblies. The lamination factor is an important indicator of core space utilization, with high-end products achieving ≥97%.
Advantages: High stamping accuracy, dimensional consistency, low core loss, high lamination factor, good stamping performance.
New Energy Vehicle Drive Motor Cores
High-grade thin-gauge non-oriented silicon steel (thickness 0.20–0.35 mm) is precision-stamped and laminated. These cores require extremely low core loss (to meet high-speed, high-frequency conditions), high magnetic flux density, and high mechanical strength to improve power density and driving efficiency.
Advantages: Significantly increases motor power density, reduces energy loss, adapts to high-speed operation.
High-efficiency Industrial Motor, Generator, and Electric Motor Laminations
Medium-to-high grade non-oriented silicon steel sheets (thickness 0.35–0.65 mm) are cross-cut or stamped to size and stacked into cores for IE3/IE4/IE5 high-efficiency motors, wind turbines, hydro generators, AC/DC motors, etc.
Advantages: Suitable for various rotating machine applications, high magnetic flux density and lamination factor, meets national and international high-efficiency standards.
Household Appliance Motor Cores
Low-to-medium grade silicon steel coils (thickness 0.35–0.50 mm) are high-speed stamped on automatic presses to produce stator/rotor laminations, then varnished and stacked. With the spread of variable-frequency appliances, demand for thin-gauge, high-grade products is increasing.
Advantages: High batch production efficiency, stable processing accuracy.
Non-Oriented Silicon Steel Mill
- Core equipment: Large converter steelmaking, RH refining furnaces, continuous casters, hot strip mills, continuous pickling lines, tandem cold mills, continuous annealing lines, insulation coating lines, 20-high precision rolling mills (for ultra-thin high-grade products – domestic production now available on high-end lines), precision stamping equipment.
- Quality control: Equipped with core loss testers (magnetic performance inspection), Epstein frames, single sheet testers, hardness testers, universal tensile testing machines (mechanical properties), lamination factor testers, roughness testers, and automatic surface defect inspection systems. All products come with inspection reports; third-party inspections such as SGS and BV are supported.
- Delivery capability: Standard mid-to-low grade products: 7–15 days; high-grade and thin-gauge products: 30–50 days. Capable of meeting JIT requirements and custom production.
Pricing of Non-Oriented Silicon Steel
Pricing methods for non-oriented silicon steel vary, including per ton (most common), per sheet, or per coil. Prices are influenced by grade, thickness specification, core loss level, type of insulation coating, custom requirements (e.g., ultra-low core loss, ultra-high magnetic flux density, special coating, specific width/length), as well as factors such as forward production scheduling, futures/spot market trading methods, packaging, and transportation conditions.
If you need a customized high magnetic-efficiency non-oriented silicon steel solution for your motor products, or have requirements for specific grades and specifications, please inform Zhongxin Steel of your specific requirements (grade, thickness, width, insulation coating type, application field, etc.) to request a quote and consult on customized solutions. We will provide professional technical support and competitive prices.