Steel 35W270-SRA
Heat-treated state
EN 35W270
SRA = stress-relief annealed after blanking
Pick when punching/laser-cut edge stress must be removed to recover the lowest core loss in finished laminations.
Values for the SRA condition
Other 35W270 tempers and conditions
35W270 is listed in 2 conditions; see the grade overview at 35W270.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SRAThis page Stress-relief annealed after blanking | Pick when punching/laser-cut edge stress must be removed to recover the lowest core loss in finished laminations. | 300 | 440 | 22 | 152 HB | 3.4 % IACS |
Final AnnealedDefault fully processed, insulation-coated strip as delivered | Standard fully-processed delivery condition: magnetic properties are already guaranteed, punch and stack directly with no further anneal. | 340 | 470 | 17 | 170 HB | 3.4 % IACS |
What is 35W270-SRA?
35W270-SRA is 35W270 heat treated to SRA — pick when punching/laser-cut edge stress must be removed to recover the lowest core loss in finished laminations. 35W270-SRA has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 86% of steel grades. Elongation at break is 22% and the elastic modulus is 185 GPa (26.8 Msi). 35W270-SRA has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 97% of steel grades. It melts at 1,480°C (2,696 °F). Final Annealed is the default condition FabDigit quotes; SRA is available on request or by drawing note.
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Poor heat conductor — 26 W/m·K (15 BTU/hr·ft·°F), worse than 87% of steel grades
- Low strength — 300 MPa (43.5 ksi), worse than 86% of steel grades
- Low electrical conductivity — 3.4 % IACS, worse than 86% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
35W270-SRA properties
Typical room-temperature values for 35W270-SRA; 19 are specific to this condition. Other listed values are 35W270 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
35W270-SRA has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 97% of steel grades. It melts at 1,480°C (2,696 °F).
Mechanical12
35W270-SRA has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 86% of steel grades. Elongation at break is 22% and the elastic modulus is 185 GPa (26.8 Msi).
Thermal6
35W270-SRA is rated for continuous service to 200°C (392 °F). It conducts heat at 26 W/m·K (15 BTU/hr·ft·°F), worse than 87% of steel grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
35W270-SRA conducts electricity at 3.4 % IACS, worse than 86% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of 35W270-SRA takes about 32 MJ of energy and emits 2.4 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 20%.
Manufacturability6
35W270-SRA's machinability is fair (38/100, worse than 80% of steel grades); weldability fair (45/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 35W270-SRA
Is 35W270 easy to machine?
Punch or laser/wire-cut rather than machine; carbide or coated tooling and sharp die clearance (~5 % of thickness) are essential because the Si-Al content is abrasive and burrs raise core loss.
Can 35W270 be welded?
TIG/laser tack or edge welding of stacks is possible but the heat-affected zone loses permeability and shorts laminations locally — prefer interlock, bonding or riveting.
Can 35W270 be formed, bent or molded?
Cold blanking and light bending only; the strip is comparatively hard and low in ductility, so avoid deep drawing and keep bend radii ≥ 2× thickness.
What surface finishes work on 35W270?
Delivered with a thin inorganic/semi-organic insulation coating; do not pickle or anodize — apply varnish impregnation or epoxy encapsulation after stacking for humidity protection.
35W270 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 is property-based; composition is producer-controlled | ≤ 0.01 | 0 |
| Siraises resistivity, lowers eddy-current loss | 2.6 – 3.2 | 2.9 |
| Al | 0.3 – 0.8 | 0.5 |
| Mn | 0.1 – 0.5 | 0.25 |
| P | ≤ 0.03 | 0.02 |
| Skept low to avoid MnS inclusions | ≤ 0.01 | 0 |
| N | ≤ 0 | 0 |
| Fe | balance | — |
35W270-SRA — frequently asked
What is 35W270-SRA used for?
35W270-SRA is typically used for motor stator and rotor laminations, EV traction motor cores, generator laminations, distribution transformer cores, high-frequency reactor and inductor cores and compressor and pump motor stacks. In short: non-oriented electrical coil.
What is the yield strength of 35W270-SRA?
35W270-SRA has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 86% of steel grades. Strength varies by condition: see the 2 listed tempers.
Is 35W270-SRA easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Punch or laser/wire-cut rather than machine; carbide or coated tooling and sharp die clearance (~5 % of thickness) are essential because the Si-Al content is abrasive and burrs raise core loss.
Can 35W270-SRA be welded?
With care — weldability is rated fair (45/100). TIG/laser tack or edge welding of stacks is possible but the heat-affected zone loses permeability and shorts laminations locally — prefer interlock, bonding or riveting.
What surface finishes work on 35W270-SRA?
Delivered with a thin inorganic/semi-organic insulation coating; do not pickle or anodize — apply varnish impregnation or epoxy encapsulation after stacking for humidity protection.
Can 35W270-SRA be formed, bent or molded?
Cold blanking and light bending only; the strip is comparatively hard and low in ductility, so avoid deep drawing and keep bend radii ≥ 2× thickness.
What is the maximum service temperature of 35W270-SRA?
35W270-SRA is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 35W270 Final Annealed and 35W270-SRA?
Final Annealed is the default condition — standard fully-processed delivery condition: magnetic properties are already guaranteed, punch and stack directly with no further anneal. SRA: pick when punching/laser-cut edge stress must be removed to recover the lowest core loss in finished laminations. Yield strength is 340 MPa in Final Annealed versus 300 MPa in SRA.
Can FabDigit make parts in 35W270-SRA?
Yes — 35W270-SRA 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
- GB/T 2521.1 Cold-rolled grain-oriented and non-oriented electrical steel strip — Part 1 (2016)
- IEC 60404-8-4 / EN 10106 Cold rolled non-oriented electrical steel sheet and strip (M250-35A class) — IEC / CEN (2013)
- Non-oriented electrical steel product handbook (B35A/35W series) — Baosteel (2022)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (magnetically soft materials) — ASM International (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.