B50A800-class non-oriented electrical steel — quick answer
Quick answer: B50A800 is the Baosteel (Q/BQB 480-2023) designation for 0.50 mm conventional non-oriented electrical steel: guaranteed maximum core loss 5.80 W/kg at 1.5 T / 50 Hz, minimum polarization 1.71 T (J5000). In the Chinese national standard GB/T 2521.1 it is written 50W800; the 0.35 mm and 0.65 mm companions on this page are B35A440 (3.40 W/kg max) and B65A600 (5.90 W/kg max). These are the cost-driven workhorse grades for standard-efficiency motors, pumps, ballasts and small transformers. If you are searching the AISI designation system instead, see our M36 / 50WW800 page — same loss class, ASTM-oriented naming.
How to read the grade designations
In B50A800: B = Baosteel Q/BQB designation, 50 = 0.50 mm nominal thickness, A = conventional non-oriented (H = high-efficiency), 800 = nominal loss 8.00 W/kg at 1.5 T / 50 Hz. The same steel under GB/T 2521.1-2016 is 50W800 (W = cold-rolled non-oriented). In EN 10106 designation the class is written M800-50A (M800 = 8.00 W/kg loss class, 50 = 0.50 mm, A = coating class), and the Japanese equivalent is JIS 50A800. Nominal values are grade identifiers; the guaranteed maximum on the mill test certificate is what governs acceptance — for B50A800 that is 5.80 W/kg.
Magnetic properties (per Baosteel Q/BQB 480-2023)
| Grade | Nominal thickness (mm) | P1.5/50 nominal (W/kg) | P1.5/50 max, guaranteed (W/kg) | Min polarization J5000 (T) | Min stacking factor | Min bending times | Conventional density (kg/dm³) |
|---|---|---|---|---|---|---|---|
| B35A440 | 0.35 | 4.40 | 3.40 | 1.67 | 0.95 | 3 | 7.70 |
| B50A800 | 0.50 | 8.00 | 5.80 | 1.71 | 0.97 | 10 | 7.80 |
| B65A600 | 0.65 | 6.00 | 5.90 | 1.68 | 0.97 | 10 | 7.75 |
B50A800 typical (non-guaranteed) values: P1.5/50 ≈ 5.0–5.4 W/kg, J5000 ≈ 1.72 T. Full magnetic curves (J1000/J2500/J5000/J10000) ship with every quotation and every original Baosteel MTC lists the measured values per heat number.
International grade equivalents
| Grade on this page | China GB/T 2521.1 | EN 10106 | JIS C 2552 | AISI (loss class) |
|---|---|---|---|---|
| B35A440 | 35W440 | M350-35A | 35A440 | M27 |
| B50A800 | 50W800 | M800-50A | 50A800 | M43–M47 |
For B65A600 (0.65 mm), GB/T 2521.1 lists 65W600; EN and JIS do not cover 0.65 mm in the standard series — confirm substitution grades case by case. Class correspondence is for reference only; test conditions differ between standards, so always confirm on the mill test certificate. See our full steel grade equivalent charts and the electrical steel equivalents guide.
Typical applications
B50A800 is the volume grade of the non-oriented family: standard-efficiency induction motors (IE1/IE2), water pumps, fans, refrigerator and air-conditioner compressors, ballasts, welding transformers and small power transformers. B35A440 serves the same applications where a thinner 0.35 mm stack improves slot fill and reduces eddy-current loss at a moderate cost premium; B65A600 is chosen for large generators, large motors and heavier-gauge cores where mechanical rigidity matters. If your design targets IE3/IE4 efficiency, step up to the 50WW470 (M27) class or the 0.35 mm M19 class instead.
Supply form, coating and packaging
Supplied mainly as coils: typical coil weight 2–6 t, inside diameter 508/510 mm, width on request (standard 900–1,250 mm); sheared sheets on request. Standard insulation coatings: semi-organic C5/C6 and chrome-free types. Export packaging: moisture-proof paper + rust-proof film + steel strapping, eye-to-sky or eye-to-wall container loading for long sea freight. Every coil ships with the original Baosteel mill test certificate.
Why Baosteel, why Baohui
Baosteel is China's largest electrical steel producer and the reference supplier for the GB/T 2521 designation system used across China's motor and transformer industry. As a Baosteel channel partner, Baohui Steel quotes B50A800-class material ex-mill or ex-warehouse with the original MTC, handles cutting, slitting and export documentation, and answers grade-substitution questions (e.g. B50A800 vs 50WW470 for a motor redesign) with engineering support. Send your grade, thickness, width and quantity for a firm FOB Shanghai quotation within 24 hours. Browse the full electrical steel category for the complete stocked range.
