Grain-Oriented Electrical Steel Processing for High-Speed Rotor Strength

The patent applies parameter changes by precisely controlling the heating temperature (at least T1, T2, or T3 calculated from alloy composition, but less than 1723 K) and coiling temperature (CT between 0.66×TX and 0.83×TX) during hot rolling. These temperature parameter adjustments optimize the formation of intermetallic phases at grain boundaries, thereby improving yield strength to at least 340 MPa while preserving the magnetic properties required for motor applications.

The patent resolves this contradiction by changing the thermal processing parameters during production. By controlling heating to specific temperatures (at least T1, T2, or T3 but less than 1723 K) and coiling at optimized temperatures (CT between 0.66×TX and 0.83×TX), the steel sheet achieves enhanced mechanical strength (yield strength ≥340 MPa). This enables the motor to operate at high rotational speeds while maintaining structural integrity, as the strengthened steel can withstand the centrifugal forces generated during high-speed rotation.

The patent employs parameter changes rather than complex alloying to improve yield strength. By adjusting the heating temperature (at least T1, T2, or T3 calculated from composition, but less than 1723 K) and coiling temperature (CT between 0.66×TX and 0.83×TX), the process achieves yield strength of at least 340 MPa using relatively simple alloy compositions (Si: 2.0-4.0%, C: 0.01-0.10%, Alsl: 0.01-0.065%, N: 0.003-0.015%, Mn: 0.01-0.5%, and small amounts of P, Cu, Mg). This approach avoids the need for complex multi-element alloying while achieving the desired mechanical properties.