Steel 35W250 · heat-treated state · default condition
Steel 35W250 Final Annealed
Properties of the Final Annealed condition, compared with the other 35W250 tempers.
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.
What is 35W250 Final Annealed?
35W250 Final Annealed is 35W250 heat treated to Final Annealed — 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. 35W250 Final Annealed 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). 35W250 Final Annealed 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).
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 Final Annealed properties
Typical room-temperature values for 35W250 Final Annealed — 10 properties are specific to this condition; the rest are grade-level values shared by every 35W250 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
35W250 Final Annealed 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).
Mechanical11
35W250 Final Annealed 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 Final Annealed 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 Final Annealed 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 Final Annealed 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 Final Annealed'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.
Other 35W250 tempers and conditions
35W250 is also supplied in 1 other condition. The full side-by-side table is on the 35W250 overview.
- Final AnnealedDefaultStandard 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 MPa yield · 82 HRB
Working with 35W250 Final Annealed
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.
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.
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 | — |
35W250 Final Annealed — frequently asked
What is 35W250 Final Annealed used for?
35W250 Final Annealed 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 Final Annealed?
35W250 Final Annealed 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 Final Annealed 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 Final Annealed 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 Final Annealed?
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 Final Annealed 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 Final Annealed?
35W250 Final Annealed 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.
Can FabDigit make parts in 35W250 Final Annealed?
Yes — 35W250 Final Annealed is available for sheet metal with instant online pricing. 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.