Steel 35W250
EN 35W250
35W250 is a fully processed (final annealed) cold-rolled non-oriented electrical steel strip to GB/T 2521, 0.35 mm thick, with a guaranteed core loss of ≤2.50 W/kg at 50 Hz and 1.5 T and a combined silicon plus aluminium content of about 3–4 %.
Values for the Final Annealed condition
35W250 tempers and conditions
35W250 is supplied in 2 conditions, soft to hard. Final Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stress-relief annealed after punching | Apply after punching or shearing (typically 750–800 °C, protective atmosphere) to relieve cut-edge stress and recover 5–15% of core loss; hardness and strength drop and the coating must tolerate the cycle. | 320 | 450 | 16 | 166 HB | 3.1 % IACS |
Final AnnealedDefault fully processed, insulation coated (as supplied) | Standard as-supplied state: mill decarburised, recrystallisation annealed and insulation coated, so laminations stack directly after punching, with core loss P1.5/50 of 2.50 W/kg or less. | 360 | 480 | 12 | 180 HB | 3.1 % IACS |
What is 35W250?
35W250 is a fully processed (final annealed) cold-rolled non-oriented electrical steel strip to GB/T 2521, 0.35 mm thick, with a guaranteed core loss of ≤2.50 W/kg at 50 Hz and 1.5 T and a combined silicon plus aluminium content of about 3–4 %. It is used for high-efficiency motors, EV traction motors, inverter compressors and medium- to high-frequency cores, where low core loss, high induction and good punchability matter. The high silicon content makes it brittle, with poor weldability and formability; welding or excessive blanking stress degrades magnetic performance, and the insulating coating is required for interlaminar insulation. 35W250 has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 97% of steel grades. It melts at 1,490°C (2,714 °F). 35W250 has a yield strength of 360 MPa (52.2 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 72% of steel grades. Elongation at break is 12% and the elastic modulus is 195 GPa (28.3 Msi).
What is 35W250 used for?
- Traction motor laminations
- High-efficiency industrial motor cores
- Inverter compressor motor stators
- Generator stator and rotor laminations
- Medium- and high-frequency core stacks
- Small transformer cores
Limitations
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Hard to polish — 40/100, worse than 96% of steel grades
- Poor heat conductor — 24 W/m·K (13.9 BTU/hr·ft·°F), worse than 90% of steel grades
- Low electrical conductivity — 3.1 % IACS, worse than 89% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
35W250 properties
Typical room-temperature values for 35W250-Final Annealed; bars are the position among steel grades.
Physical3
35W250 has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 97% of steel grades. It melts at 1,490°C (2,714 °F).
Mechanical14
35W250 has a yield strength of 360 MPa (52.2 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 72% of steel grades. Elongation at break is 12% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
35W250 is rated for continuous service to 180°C (356 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), worse than 90% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
35W250 conducts electricity at 3.1 % IACS, worse than 89% of steel grades.
Chemical & Environmental2
Corrosion resistance is poor (18/100), better than 83% of steel grades.
Sustainability4
Producing a kilogram of 35W250 takes about 32 MJ of energy and emits 2.4 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 15%.
Manufacturability7
35W250's machinability is fair (45/100, worse than 65% of steel grades); weldability fair (35/100); formability fair (45/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 35W250 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 35W250
Is 35W250 easy to machine?
Process by precision blanking or laser cutting; the high silicon content and the coating are abrasive, so use carbide punch tooling and regrind often to keep burr height ≤5 % of strip thickness. Conventional chip machining is uneconomic.
Can 35W250 be welded?
Avoid welding: it short-circuits laminations, and HAZ grain growth and residual stress raise core loss. Where a stack must be fixed, use short tack or laser spot welds and accept the loss in magnetic performance.
Can 35W250 be formed, bent or molded?
Suitable only for flat blanking and shallow bends; keep the bend radius ≥1.5t and bend along the rolling direction. Cold bendability of 3 % Si material is poor — no deep drawing or large deformation.
Manufacturability
The process limits FabDigit applies to 35W250. Every 35W250 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
Sheet metal
| Formability | Better45 / 100 |
|---|---|
| Weldability | Poor35 / 100 |
| Bendable | Yes |
35W250 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CGB/T 2521 grade by magnetic loss; typical high-grade non-oriented | ≤ 0.01 | 0 |
| Si | 2.6 – 3.4 | 3 |
| AlSi+Al raise resistivity and lower eddy-current loss | 0.3 – 1 | 0.6 |
| Mn | 0.1 – 0.5 | 0.25 |
| P | ≤ 0.05 | 0.02 |
| S | ≤ 0.01 | 0 |
| N | ≤ 0 | 0 |
| Fe | balance |
What surface finishes work on 35W250?
Supplied with an inorganic or semi-organic insulating coating (C-3/C-5/C-6 types); do not abrade before stacking. If stress-relief annealing is needed after blanking, run it in a protective atmosphere and confirm the coating temperature rating.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
Black / Phosphate
Thermal Spray
How much does 35W250 cost?
35W250 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
35W250 — frequently asked
What is 35W250 used for?
35W250 is typically used for traction motor laminations, high-efficiency industrial motor cores, inverter compressor motor stators, generator stator and rotor laminations, medium- and high-frequency core stacks and small transformer cores. In short: workhorse electrical-steel coil.
What is the yield strength of 35W250?
35W250 has a typical yield strength of 360 MPa (52.2 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 72% of steel grades. Strength varies by condition: see the 2 listed tempers.
Is 35W250 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Process by precision blanking or laser cutting; the high silicon content and the coating are abrasive, so use carbide punch tooling and regrind often to keep burr height ≤5 % of strip thickness. Conventional chip machining is uneconomic.
Can 35W250 be welded?
With care — weldability is rated fair (35/100). Avoid welding: it short-circuits laminations, and HAZ grain growth and residual stress raise core loss. Where a stack must be fixed, use short tack or laser spot welds and accept the loss in magnetic performance.
What surface finishes work on 35W250?
Supplied with an inorganic or semi-organic insulating coating (C-3/C-5/C-6 types); do not abrade before stacking. If stress-relief annealing is needed after blanking, run it in a protective atmosphere and confirm the coating temperature rating.
Can 35W250 be formed, bent or molded?
Suitable only for flat blanking and shallow bends; keep the bend radius ≥1.5t and bend along the rolling direction. Cold bendability of 3 % Si material is poor — no deep drawing or large deformation.
What is the maximum service temperature of 35W250?
35W250 is rated for continuous use to about 180°C (356 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 35W250 Final Annealed and 35W250-SRA?
Final Annealed is the default condition — standard as-supplied state: mill decarburised, recrystallisation annealed and insulation coated, so laminations stack directly after punching, with core loss P1.5/50 of 2.50 W/kg or less. SRA: apply after punching or shearing (typically 750–800 °C, protective atmosphere) to relieve cut-edge stress and recover 5–15% of core loss; hardness and strength drop and the coating must tolerate the cycle. Yield strength is 360 MPa in Final Annealed versus 320 MPa in SRA.
How much does 35W250 cost?
35W250 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in 35W250?
Yes — 35W250 is available for sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- IEC 60404-8-4 Specification for cold-rolled non-oriented electrical steel strip and sheet — IEC (2013)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (soft magnetic materials) — ASM International (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.