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I. Misconceptions About Material Properties of Silicon Steel Sheets

Silicon steel sheets, also known as electrical steel, are the invisible core component of power equipment. Their hardness presents contradictory characteristics:

• Soft magnetic principle: Alloy formulations with 3%–4.5% silicon deliver exceptional mobility of magnetic domains, professionally referred to as soft magnetic properties.
• Mechanical reality: Its Rockwell hardness HRB ranges from 65 to 85, equivalent to the hardness of brass.
• Thickness variation: Ultra-thin 0.2 mm gauges feel relatively soft, while sheets thicker than 1 mm become noticeably harder.

II. Core Considerations for Industrial Material Selection

Selecting silicon steel sheets is similar to choosing down quilts; hardness cannot be the sole evaluation criterion:

• Magnetic performance takes precedence: Hardness concessions are acceptable to guarantee high magnetic permeability. Each 1% rise in silicon content reduces core loss by 15%.
• Balanced processing solutions:
  • Soft DR grades (HRB 60–70) for stamping operations
  • Harder HiB grades (HRB 75–85) for transformer manufacturing
• Influence of surface coating: Insulating coatings raise hardness by 0.5–1 HRB units.

III. Special Precautions for Application

Even veteran engineers may overlook these critical details:

• Stress susceptibility: Bending leads to permanent degradation of magnetic performance; a bending radius greater than 5 times the sheet thickness is recommended.
• Hardness deviation risk: Hardness fluctuation of up to 10% exists across different batches of the same grade; actual test reports should be requested.
• Temperature effect: Hardness decreases by approximately 8% for every 100 °C temperature rise, so safety allowances must be reserved during design.