For easy comparison, their core differences are summarized by dimension below:

1. Microstructure & Production Process

• Non-Oriented (NO) Steel:

• Grain Orientation: Grains are       randomly distributed and uniformly oriented without a specific pattern.

• Silicon Content: Typically       lower or medium silicon content to ensure magnetic isotropy.

• Process Focus: No special       orientation rolling treatment is applied during production; the goal is       material uniformity.

• Grain-Oriented (GO) Steel:

• Grain Orientation: After       special rolling and heat treatment, grains are aligned in a specific       direction (usually the rolling direction).

• Silicon Content: Usually       higher silicon content to reduce iron loss and promote grain growth.

• Process Focus: Requires       strict and complex processes (like secondary recrystallization) to       achieve a single Goss texture; the process window is very narrow.

2. Magnetic Properties

• Non-Oriented (NO) Steel:

• Isotropy: Magnetic properties       are essentially consistent in all directions (0°, 45°, 90°) on the sheet       plane.

• Permeability: High       permeability in low to medium magnetic fields, but not as high as GO       steel in the rolling direction under high magnetic flux.

• Core Loss: Eddy current       losses are well-controlled under high-frequency conditions (e.g., 400Hz       and above).

• Grain-Oriented (GO) Steel:

• Strong Anisotropy: Magnetic       properties are best along the rolling direction (high permeability, low       core loss), while properties perpendicular to the rolling direction are       poor.

• High Magnetic Flux Density: Easily       achieves high magnetic flux density (e.g., B8 above 1.9T) when excited       along the rolling direction, allowing for a smaller core cross-section.

• Core Loss: Extremely low core       loss along the rolling direction at power frequencies (50/60Hz), but loss       increases sharply when the flux deviates from this direction.

3. Application Fields

• Non-Oriented (NO) Steel:

• Rotating Machines: Primarily       used in various motors (e.g., EV traction motors,       compressor motors, industrial motors) and generators. Because       the rotor rotates and the magnetic field direction constantly changes,       materials with isotropic magnetic properties are necessary.

• Small Appliances & Transformers: Used in small transformers, chokes, and high-frequency       switching power supplies.

• Grain-Oriented (GO) Steel:

• Static Equipment: Mainly used       in the cores of transformers (power transformers,       distribution transformers). The magnetic flux flows along the closed path       of the core (which aligns with the rolling direction).

• Large Motors: Occasionally       used in the stators of large turbine generators (designs leverage the       high permeability direction), though the design is complex.

4. Thickness Specifications

• Non-Oriented (NO) Steel: Wide      range of thicknesses, commonly 0.35mm, 0.50mm, 0.65mm; to meet      high-frequency trends, EV traction motors often use thinner grades like      0.25mm, 0.20mm, and even 0.10mm.

• Grain-Oriented (GO) Steel: Typically      thinner standard thicknesses, mainly 0.23mm, 0.27mm, 0.30mm, 0.35mm;      ultra-thin grades like 0.18mm and 0.15mm are also being developed to      further reduce eddy current losses.

5. Domain Refinement

• Non-Oriented (NO) Steel: Generally,      domain refinement treatment (e.g., laser scribing) is not applied. The      fine and randomly oriented grains naturally achieve a similar effect.

• Grain-Oriented (GO) Steel: High-grade      products (laser-scribed or mechanically scribed) often undergo domain      refinement. Because GO steel has large grains, scribing divides large      domains into smaller ones, significantly reducing anomalous eddy current      losses and improving the product grade.

6. Cost & Price

• Non-Oriented (NO) Steel: Relatively      simpler production process, higher yield, generally lower price.      Mid-to-low grade non-oriented steels have a significant cost advantage.

• Grain-Oriented (GO) Steel: Complex      production process, long process flow, difficult quality control,      especially for High Permeability (Hi-B) grades. It is expensive,      typically costing double or even several times more than non-oriented      steel.

Summary:
Simply put, Grain-Oriented steel is a "specialist," excelling in a single direction, making it ideal for devices like transformers where the magnetic field path is fixed. Non-Oriented steel is a "generalist," with balanced properties in all directions, suitable for devices like motors that require a rotating magnetic field. The choice depends entirely on whether the magnetic field path in the application is fixed or rotating.