Magnetic Properties (Low Core Loss, High Permeability)
Our electrical silicon steel features low core loss and high magnetic permeability, which significantly reduce energy consumption and improve efficiency in transformers and motors. With excellent magnetic performance, our material ensures stable operation under high-efficiency, energy-saving conditions, providing strong support for advanced electrical applications.
Processing Property (Suitable for Stamping and Cutting)
The material offers excellent workability, with good toughness and low brittleness, making it highly suitable for stamping, shearing, and complex shape processing. It maintains high dimensional accuracy and resists surface cracking during fabrication, which enhances production efficiency and guarantees superior quality in finished components.
Dimension Tolerance (Minimal Variation)
Our products are manufactured with strict thickness and width control, ensuring minimal deviation and outstanding uniformity. The precise tolerance guarantees tight stacking in motor and transformer cores, reduces magnetic circuit loss, and improves the overall performance and reliability of electrical equipment.
Insulation Coating (Heat Resistant, Corrosion Resistant, High Insulation)
The insulation coating provides strong adhesion and offers excellent heat resistance, corrosion resistance, and high insulation properties. It remains stable during stamping and long-term operation, effectively preventing interlaminar short circuits and extending the service life of electrical devices.
TESTING AND CERTIFICATION
Products
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Online ultrasonic testing
Online ultrasonic testing
Laboratory iron loss test
Laboratory iron loss test
Surface inspection
Surface inspection
MTC Sample_Sheet
Weighting before loading
Packing and marking inspection
TESTING STANDARD DESCRIPTION
Epstein Square Ring Method for Measuring the Magnetic Properties of Electrical Steel Strip (Sheet)
1.Scope
This standard applies to the measurement of the magnetic properties of grain-oriented and grain-non-oriented steel strip (sheet). The purpose of this standard is to define the general principles and technical details of the Epstein Square Ring Method for measuring the magnetic properties of electrical steel strip (sheet).
2.General Principles
2-1.Principle of the Epstein Square Ring Method
The Epstein Square Ring consists of a primary coil, a secondary coil, and a specimen serving as the core, forming an unloaded transformer. Its AC characteristics are measured according to the method described below.
2-2.Specimens
Specimens are assembled into a square frame using double-lap joints and formed into four bundles of equal length and cross-sectional area. Specimens should be prepared in accordance with the requirements of the relevant product standards. Specimens should be cut using a method that does not produce edge burrs. If required, they should be processed in accordance with the relevant product standards. Specimens should have the following dimensions: Width: B = 30 mm ± 0.2 mm; Length: 280 mm ≤ L ≤ 320 mm. The length tolerance of the specimen is ±0.5 mm. When cutting specimens along or perpendicular to the rolling direction, the rolling direction of the parent sheet should be used as a reference: For grain-oriented electrical steel sheet, ±1°; for non-grain-oriented electrical steel sheet, ±5°. The specimen should be straight.
3.Power Supply
The power supply should have low internal resistance and highly stable voltage and frequency. During measurement, the voltage and frequency should be maintained constant within ±0.2%. For RMS measurements of specific total loss, specific apparent power, and magnetic field strength, the crest factor of the secondary voltage should be 1.111 ± 1%. Two voltmeters are required to measure the crest factor of the secondary voltage: one for the RMS value of the secondary voltage and one for the average value of the rectified secondary voltage.
3-1.Voltage Measurement
The secondary voltage of the Epstein ring should be measured using a voltmeter with a low internal resistance of not less than 1000 Ω/V.
3-2.Frequency Measurement
A frequency meter with an accuracy of ±0.1% or better should be used.
3-3.Wattage Meter
A wattage meter with an accuracy of ±0.5% or better at the actual power factor and crest factor should be used.
4.Total Loss Measurement Procedure
4-1.Measurement Preparation
The Epstein ring and measuring equipment should be connected as if using an air flux compensation mutual inductance coil.
Weigh the specimen within an error of ±0.1%. After weighing, the specimen should be stacked in the Epstein ring in a double-lap arrangement at the corners, with an equal number of specimens in each leg of the ring, resulting in a square with an inner edge of 220 mm. When the specimens are sheared with half parallel to the rolling direction and half perpendicular to the rolling direction, the strips sheared in the rolling direction should be inserted into two opposite legs of the ring, while those sheared perpendicular to the rolling direction should be inserted into the other two legs. Care should be taken to ensure that the air gap between the overlapping strips is as small as possible. A force of approximately 1 N is allowed to be applied perpendicular to the joint surface of the sample at each overlap angle.
4-2.Power supply regulation
The output of the power supply is slowly increased while observing the ammeter of the primary circuit to ensure that the current circuit of the power meter is not overloaded, and the average value of the secondary voltage after rectification directly to the Epstein square reaches the predetermined value.
4-3.Reproducibility of the total loss measurement
The reproducibility of the results obtained using the described method is expressed as a relative standard deviation, which is 1.5% for grain-oriented electrical steel when the magnetic polarization intensity is not greater than 1.7 T and for grain-non-oriented electrical steel when the magnetic polarization intensity is not greater than 1.5 T. For measurements at higher magnetic polarization intensity, the relative standard deviation is expected to increase.
5.Test report
The test report should include the following:
(1) This standard number;
(2) Type and identification of the specimen;
(3) Density of the material (conventional value);
(4) Length of the specimen;
(5) Number of specimens;
(6) Mass of the specimen;
(7) Material frequency;
(8) Measurement results.
QUALITY CONTROL PROCESS
Quality Control Process of Electrical Steel
1.General Objective
Electrical steel is a critical soft magnetic material widely used in transformers, motors, and generators. The quality control process focuses on stable magnetic performance, low core loss, and good mechanical processability, covering the entire chain from raw materials → production → testing → delivery.
2.Grain-Oriented Electrical Steel (GO)
GO steel is mainly used for transformer cores, requiring excellent magnetic permeability and very low core loss in the rolling direction. Its quality control process is highly stringent.
2-1.Raw Material Control
• Strict control of low C, S, N, and O contents. • Addition of inhibitors (e.g., Al, Mn, S, Se, N) to promote secondary recrystallization. • Cleanliness of molten steel checked by O, N, S analysis.
2-2.Casting & Hot Rolling
• Continuous casting inspection to avoid cracks and inclusions. • Precise hot rolling temperature curve to ensure uniform structure.
2-3.Cold Rolling & Intermediate Annealing
• Multi-pass cold rolling for dimensional accuracy and flatness. • Intermediate annealing to release stresses and refine grains.
Grain-oriented silicon steel is produced by cold-rolling oriented silicon steel, then alkali-washing, decarburizing, and annealing, then coating it with a magnesium oxide barrier layer. The steel undergoes high-temperature annealing, tension coating, and stretching and hot-smoothing. Its production process is complex and technically demanding. It is primarily used in the manufacture of various transformers and is an indispensable soft magnetic material in the power and electronics industries, boasting high magnetic induction and low iron loss.
Production Equipment Overview:
Uncoiler, welding machine, alkali-washing system, magnesium coating system, drying system, winder, bell-type annealing furnace, uncoiler, riveting machine, roller brushing machine, pickling system, cleaning system, coating system, drying furnace, annealing and smoothing furnace, and winder. Our company utilizes advanced laser scoring technology, achieving invisible scoring lines. Laser scoring of oriented silicon steel involves surface laser scoring. Leveraging the rapid localized heating and cooling of lasers, this technology induces microplastic deformation and high-density dislocations in the heated area, reducing the main domain wall length of the oriented silicon steel. This results in refined magnetic domains and reduced iron loss.
Production Equipment Overview: The main equipment flow includes: uncoiler, inlet S-roller, laser scoring unit, outlet S-roller, and winder.
CRNGO
Cold-rolled non-oriented silicon steel is produced by cold-rolling medium- and low-grade non-oriented silicon steel, followed by complete decarburization and continuous deannealing after alkali washing, and then applying an insulating coating. Cold-rolled non-oriented silicon steel is widely used in household appliances, industrial motors, transformers, and compressor motors.
Production Equipment Overview:
Uncoiler, double-layer shear, welding machine, inlet looper, alkali washing system, preheating furnace, heating furnace, soaking pit, jet cooler, water quenching unit, coating system, drying furnace, sintering furnace, air jet cooling outlet looper, and coiler.
We have more than 20+ years of experience in the electrical steel market and over 16+ years of manufacturing experience.
