Designers outside the motor industry find electrical steel nomenclature opaque. It is simpler than it looks, and understanding it saves real money on every tonne.
In the EN system, 50W470 means: 0.50 mm thick, W for non-oriented, and 470 the maximum specific total loss at 1.5 T and 50 Hz, in W/kg. The Japanese JIS system (50A470, 50H470) and the Chinese GB system (50W470) describe the same property. So the number after the W is the whole story: lower loss, better motor, higher price.
Eddy-current losses fall with the square of thickness, which is why 0.35 mm exists alongside 0.50 mm. High-speed machines and premium-efficiency motors justify 0.35 mm; standard industrial motors at 50 Hz are usually designed around 0.50 mm, where the cost per tonne is significantly lower.
Two grades with the same core loss can magnetise differently. If your design runs near saturation — small motors, high pole counts — ask for the magnetisation curve, not just the loss figure. Reputable mills publish both.
The insulating coating controls interlaminar loss, punchability and welding behaviour. C5 (semi-organic) suits most stamped cores; C6 adds weldability for welded stator stacks. If your process anneals after punching, the coating chemistry must be specified for annealing — not every mill offers it, and substituting silently ruins the stack.
Grade-for-grade, Chinese mills (Baosteel, Masteel, WISCO) now produce material that meets EN 10106 and JIS C2552 requirements with full certification, generally at a lower landed cost than European or Japanese origin. The practical check is the certificate: it should state core loss, induction and coating thickness per coil, measured to IEC 60404.
Send the grade, the size and the quantity — you get a costed quotation within two working days.