Ultra-thin silicon steel sheets are a key material for enabling the development of modern electrical equipment towards higher efficiency, higher frequency, and miniaturization. They are of significant importance for enhancing device performance and energy utilization efficiency.
Meaning of Ultra-Thin Silicon Steel Sheets
Ultra-thin silicon steel sheets refer to silicon steel materials with an extremely thin gauge, typically not exceeding 0.1mm. Common thickness specifications include 0.05mm, 0.03mm, and 0.02mm. They are produced through specialized manufacturing processes that further reduce thickness compared to conventional silicon steel, while maintaining or improving their magnetic and physical properties.
Characteristics of Ultra-Thin Silicon Steel Sheets
Ultra-thin silicon steel sheets are high-performance soft magnetic materials used in high-frequency, high-power-density applications, featuring the following notable characteristics:
Extremely Thin Gauge: Thickness typically ranges from 0.05mm to 0.1mm, far below that of traditional silicon steel sheets. This effectively reduces eddy-current loss, making them suitable for high-frequency (400 Hz-10kHz and above) applications such as high-frequency transformers and motor cores.
Low Iron Loss: Through optimized composition and processing, core loss (iron loss) at high frequencies is significantly reduced. For instance, at frequencies like 400Hz or 1000Hz, iron loss can be maintained at low levels (e.g., P1.0/400 ≤ 12 W/kg), contributing to improved equipment energy efficiency and reduced heat generation.
High Magnetic Induction: Capable of maintaining high magnetic flux density (e.g., B8000 ≈ 1.7-1.9T) under strong magnetic fields. This allows for reduced volume and weight of motor and transformer cores, leading to increased power density and facilitating equipment miniaturization and lightweight design.
High Permeability: Possesses good permeability, which can improve energy conversion efficiency and reduce hysteresis loss. Suitable for high-frequency motors, inductors, and other components requiring high magnetic performance.
Stable Magnetic Properties: Subjected to special treatments, magnetic aging is not significant, and magnetic properties remain stable over long-term use. Suitable for high-end electronic equipment and new energy vehicle applications where high reliability is required.
Inspection of Ultra-Thin Silicon Steel Sheets
Appearance and Dimension Inspection
| Surface Quality: The surface should be smooth, free from rust, oxidation spots, oil stains, scratches, dents, holes, delamination, or foreign material adhesion. The coating should be uniform, continuous, and without peeling. Edges and central areas of coils require focused inspection.
| Thickness Accuracy: Measured using a micrometer or laser thickness gauge. Thickness tolerance must meet standard requirements (e.g., ±0.02mm or as per agreement). Thickness variation across a single sheet should be ≤ 0.005mm. Three points each at the head, middle, and tail of a coil should be measured.
| Width and Length: Width measured with calipers or a projector; tolerance must conform to standards (e.g., ±0.5mm). For cut-to-length sheets, length must be checked against order requirements using a tape measure or laser length gauge.
| Flatness: Check for issues like camber, edge wave, or center wave. Camber should be ≤ 1.5mm/m; wave height for edge or center wave should be ≤ 1mm/m to avoid affecting stamping and lamination quality.
Magnetic Property Testing
| Iron Loss (Core Indicator): Iron loss is a key metric for assessing silicon steel sheet quality. Grades are typically classified based on iron loss values in various countries, with lower iron loss indicating a higher grade and better quality. Professional magnetic testing equipment (e.g., Epstein frame or permeameter) must be used to measure iron loss at specified frequencies (e.g., 50Hz or 400Hz) and flux densities. Measured values should be ≤ the nominal grade value.
| Magnetic Induction: Silicon steel sheets with higher magnetic induction under the same magnetic field can improve the efficiency of motors or transformers and reduce their volume and weight. Indicators like magnetic polarization intensity (e.g., B50 ≥ 1.70T) must be tested to ensure compliance with the corresponding grade requirements.
| Coercivity and Permeability: High-quality silicon steel sheets should have low coercivity (e.g., ≤ 40 A/m) and high relative permeability (e.g., ≥ 3000). These indicators affect hysteresis loss and excitation current.
Chemical Composition Analysis
The chemical composition is analyzed via spectrometry or chemical methods. Silicon content is generally 2.5%~3.5%, carbon content ≤ 0.005%, and impurity elements like sulfur and phosphorus should be ≤ 0.015%. Appropriate chemical composition is fundamental for ensuring magnetic properties and machinability.
Applications of Ultra-Thin Silicon Steel Sheets
| High-Frequency Transformers: Used in high-frequency transformers within equipment like switching power supplies, inverters, and charging piles. Ultra-thin silicon steel sheets can effectively reduce iron loss, improving transformer efficiency and reliability.
| New Energy Vehicles: Used in components like drive motors and compressors. They can improve motor efficiency and power density, extending battery range.
Magnets Manufacturer
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Image Source: Huaxiaometal & Itacamagnetics & Nipponkinzoku & Shungesteeltrade & Silicon-steels
