M27-class non-oriented electrical steel — quick answer
Quick answer: M27 is an AISI loss class for 0.50 mm non-oriented electrical steel. The Baosteel equivalents are 50WW470 (enterprise grade, max 3.30 W/kg P1.5/50) and B50A470 (GB/T 2521.1 grade, max 4.20 W/kg P1.5/50), also written 50W470 under GB/T 2521.1-2016. In EN 10106 designation this is the M470-50A class; the Japanese class equivalent is JIS 50A470. It is the most widely used industrial grade worldwide — general-purpose motors, generators, pumps, fans and small transformers.
How to read the grade designations
Electrical steel grades encode thickness and core loss. In 50WW470: 50 = 0.50 mm nominal thickness, WW = conventional non-oriented (WH = high-efficiency), 470 = nominal loss 4.70 W/kg at 1.5 T / 50 Hz. In B50A470: B = Baosteel Q/BQB designation, 50 = 0.50 mm, A = conventional non-oriented, 470 = same nominal loss. In EN M470-50A: M470 = 4.70 W/kg loss class, 50 = 0.50 mm, A = insulation coating class. AISI M27 belongs to the same loss class but is specified in W/lb at 1.5 T / 60 Hz, so the numbers are not directly comparable.
Magnetic properties (per Baosteel Q/BQB 480-2023)
| Grade | Nominal thickness (mm) | Max core loss P1.5/50 (W/kg) | Min polarization J5000 (T) | Min stacking factor | Typical density (kg/dm³) |
|---|---|---|---|---|---|
| B50A310 | 0.50 | 2.75 | 1.69 | 0.97 | 7.65 |
| 50WW350 | 0.50 | 3.00 | 1.70 | 0.97 | 7.70 |
| 50WW400 | 0.50 | 3.30 | 1.70 | 0.97 | 7.70 |
| 50WW470 | 0.50 | 3.30 | 1.70 | 0.97 | 7.70 |
| B50A470 | 0.50 | 4.20 | 1.67 | 0.97 | 7.70 |
| 50WW600 | 0.50 | 4.20 | 1.68 | 0.97 | 7.75 |
| B50A600 | 0.50 | 4.70 | 1.68 | 0.97 | 7.75 |
Typical (non-guaranteed) values for 50WW470: P1.5/50 ≈ 3.20 W/kg, P1.0/50 ≈ 1.36 W/kg, P1.5/60 ≈ 4.00 W/kg. Full magnetic curves (J1000/J2500/J5000/J10000) ship with every quotation.
International grade equivalents
| China Q/BQB 480-2023 | China GB/T 2521.1 | EN 10106 | JIS C 2552 (class) | AISI (class) |
|---|---|---|---|---|
| B50A310 / 50WW310 | 50W310 | M330-50A | 50A310 | M19 |
| B50A400 / 50WW400 | 50W400 | M400-50A | 50A400 | M22 |
| B50A470 / 50WW470 | 50W470 | M470-50A | 50A470 | M27 |
| B50A600 / 50WW600 | 50W600 | M600-50A | 50A600 | M36 |
| B50A700 | 50W700 | M700-50A | 50A700 | M43 |
Class correspondence for reference only — test conditions differ between standards. Confirm the exact grade on the mill test certificate before ordering. See our full steel grade equivalent charts.
Typical applications
0.50 mm M27-class NGO steel is the global workhorse for general-purpose electrical machines: three-phase industrial motors (IE2/IE3), generators and alternators, water pumps, fans, compressors, hoists, and small distribution transformer cores. Where duty cycles are long and energy costs matter, designers step up to 50WW400-class material; for cost-sensitive short-duty equipment 50WW600 is the common alternative — we quote all of them against one enquiry.
Supply form, coating and packaging
Supplied as slit coils: typical coil weight 2–6 t, inside diameter 508/510 mm, width on request (standard 900–1,250 mm). Standard insulation coatings include semi-organic C5/C6 and chrome-free types; self-bonding coatings available on request. Export packaging: moisture-proof paper + steel strapping, eye-to-sky or eye-to-wall container loading. Every coil ships with the original Baosteel mill test certificate (magnetic values per heat number).
Why Baosteel, why Baohui
Baosteel is China's largest and the world's leading electrical steel producer, and 50WW470-class material is its highest-volume NGO grade — stable quality, short lead times and deep width/thickness coverage. As a Baosteel channel partner, Baohui Steel quotes M27-class material ex-mill or ex-warehouse with the original MTC, handles cutting-to-length and export documentation, and answers grade-substitution questions (e.g. 50WW470 vs 50WW400 for an IE3 motor redesign) with engineering support. Send your grade, thickness, width and quantity for a firm FOB Shanghai quotation within 24 hours.
