Blog

I. Factors Affecting Yield Strength

The yield strength of silicon steel sheets is mainly governed by two factors: silicon content and heat treatment process. Each 1% increase in silicon content normally raises yield strength by approximately 15–20 MPa. This is because silicon atoms dissolved in ferrite can effectively block dislocation movement.

Within heat treatment procedures, annealing temperature and holding time exert a notable impact on grain size. For instance, when annealing at 850°C, extending the holding time from 2 hours to 4 hours may enlarge grain size by 30%, resulting in roughly a 10% drop in yield strength.

Yield strength varies greatly among common silicon steel grades:

• Non-oriented electrical steel (e.g. B23RT080): generally 280–300 MPa
• High-silicon steel (3.5% silicon content): can exceed 310 MPa
• Thin-gauge silicon steel for new energy vehicle motors (e.g. B18P080): slightly lower than standard values due to reduced thickness

II. Comprehensive Considerations for Material Selection

Yield strength alone cannot be the sole criterion for practical selection. Silicon steel with a magnetic flux density B50 above 1.7 T often sees its yield strength fall below 270 MPa. Meanwhile, materials with favorable stamping workability usually require yield strength controlled under 290 MPa to prevent excessive die wear.

When selecting materials, first clarify whether magnetic performance or mechanical strength takes priority for the equipment, then screen specific grades within the corresponding performance range.