Steel Silicon Steel
Silicon steel (electrical steel) is a low-carbon Fe-Si alloy, typically 0.5–3.5 % Si with very low C, S and N, rolled into thin strip for magnetic cores.
Values for the Annealed condition
Silicon Steel tempers and conditions
Silicon Steel is supplied in 8 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stress-relief annealed after stamping/slitting | Apply after punching, bending or slitting to recover permeability and remove the loss penalty from cut edges and burrs. | 300 | 440 | 25 | 157 HB | 3.4 % IACS |
high-permeability grain-oriented (optionally laser-scribed) | Premium transformer grade: sharper Goss texture plus tensile coating/laser scribing for the lowest core loss at high induction. | 315 | 370 | 7 | 10 HRC | 3.6 % IACS |
AnnealedDefault fully processed, decarburized and final-annealed strip | Default stocked condition: magnetic properties already developed, ready to punch and stack without further annealing. | 320 | 460 | 20 | 170 HB | — |
Cold-rolled grain-oriented (Goss texture), fully processed | Use for transformer and reactor cores where flux runs along the rolling direction; lowest loss but strongly anisotropic. | 320 | 380 | 8 | 10 HRC | 3.6 % IACS |
Cold-rolled non-oriented, fully processed with core-plate coating | Standard motor/generator lamination material: isotropic in-plane magnetics, coated for interlaminar insulation. | 330 | 470 | 20 | 9 HRC | 3.4 % IACS |
hot-rolled silicon steel sheet/band | Legacy/low-cost option for thick laminations, small transformers and pole pieces where loss targets are loose. | 330 | 500 | 22 | 160 HB | 5.7 % IACS |
supplied hard-ish, customer anneals after stamping | Pick for high-volume motor laminations where the stamper runs its own decarburize/grain-growth anneal to hit final loss values. | 360 | 490 | 16 | 11 HRC | 4.9 % IACS |
as-cold-rolled (un-annealed, work-hardened) strip | Choose when high stiffness/strength and tight thickness tolerance matter and the part will be annealed later, or for non-magnetic structural use of the strip. | 580 | 650 | 5 | 20 HRC | 3.4 % IACS |
What is Silicon Steel?
Silicon steel (electrical steel) is a low-carbon Fe-Si alloy, typically 0.5–3.5 % Si with very low C, S and N, rolled into thin strip for magnetic cores. The silicon raises electrical resistivity and reduces magnetocrystalline anisotropy, cutting eddy-current and hysteresis losses, while decarburized annealing grows coarse, texture-controlled grains for high permeability. Limits are brittleness and tool abrasiveness at high Si, mediocre corrosion resistance (needs insulating/phosphate coatings), and loss of magnetic quality if the strip is over-stressed, welded or stamped without stress-relief annealing. Silicon Steel has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 97% of steel grades. It melts at 1,500°C (2,732 °F). Silicon Steel has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 81% of steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi).
What is Silicon Steel used for?
- Transformer cores
- Electric motor stator and rotor laminations
- Generator and alternator cores
- Inductor and choke cores
- Current and instrument transformer cores
- Solenoid and relay armatures
- Magnetic shielding sheet
Advantages
- Forms and bends easily — 62/100, better than 78% of steel grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Poor heat conductor — 22 W/m·K (12.7 BTU/hr·ft·°F), worse than 93% of steel grades
- Low electrical conductivity — 3.6 % IACS, worse than 85% of steel grades
- Low strength — 320 MPa (46.4 ksi), worse than 81% of steel grades
- Difficult to machine — 38/100, worse than 80% of steel grades
Silicon Steel properties
Typical room-temperature values for Silicon Steel-Annealed; bars are the position among steel grades.
Physical3
Silicon Steel has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 97% of steel grades. It melts at 1,500°C (2,732 °F).
Mechanical12
Silicon Steel has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 81% of steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
Silicon Steel is rated for continuous service to 200°C (392 °F). It conducts heat at 22 W/m·K (12.7 BTU/hr·ft·°F), worse than 93% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
Silicon Steel conducts electricity at 3.6 % IACS, worse than 85% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of Silicon Steel takes about 34 MJ of energy and emits 2.3 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
Silicon Steel's machinability is fair (38/100, worse than 80% of steel grades); weldability fair (45/100); formability good (62/100).
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. Silicon Steel is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Silicon Steel
Is Silicon Steel easy to machine?
Silicon makes chips abrasive and burr-prone — use sharp carbide or coated HSS, generous flood coolant, and expect fast tool wear; thin strip is normally punched or laser/EDM cut rather than machined.
Can Silicon Steel be welded?
Weldable by TIG/laser/resistance after stripping core-plate, but the HAZ grows coarse or oxidized and raises core loss — keep welds off the flux path or stress-relief anneal afterwards.
Can Silicon Steel be formed, bent or molded?
Fully processed strip stamps and bends well with sharp, well-maintained tooling (clearance ~5 % of thickness); high-Si and grain-oriented grades are notch-sensitive and crack on tight bends.
Manufacturability
The process limits FabDigit applies to Silicon Steel. Every Silicon Steel part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
Sheet metal
| Formability | Fair62 / 100 |
|---|---|
| Weldability | Fair45 / 100 |
| Bendable | Yes |
Silicon Steel 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 |
|---|---|---|
| Si≈0.5–1.5 % low grades, 2.5–3.5 % high grades and all grain-oriented | 0.5 – 3.5 | 3 |
| Cdecarburized to <0.005 % in fully processed strip | 0 – 0.03 | 0 |
| Mn | 0.05 – 0.5 | 0.2 |
| Alresistivity/grain-growth control in NGO; AlN inhibitor in GO | 0.05 – 0.6 | 0.3 |
| P | ≤ 0.06 | 0.02 |
| SMnS inhibitor in conventional GO | ≤ 0.02 | 0.01 |
| N | ≤ 0.01 | 0 |
| Snoptional grain-boundary segregant in some GO grades | ≤ 0.1 | |
| Fe | balance |
What surface finishes work on Silicon Steel?
Normally used as supplied with inorganic/organic core-plate (C-3/C-5/C-6) or phosphate insulation; bare edges need varnish, oil or paint since the steel rusts readily. Not anodizable.
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
Equivalent designations
Standards and trade names that resolve to Steel Silicon Steel in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- Fe-Si Electrical Steel
How much does Silicon Steel cost?
Silicon Steel is a premium-cost steel ($$$), cheaper than about 62% 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.
Silicon Steel — frequently asked
What is Silicon Steel used for?
Silicon Steel is typically used for transformer cores, electric motor stator and rotor laminations, generator and alternator cores, inductor and choke cores, current and instrument transformer cores and solenoid and relay armatures. In short: superior magnetic properties.
What is the yield strength of Silicon Steel?
Silicon Steel has a typical yield strength of 320 MPa (46.4 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 81% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is Silicon Steel easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Silicon makes chips abrasive and burr-prone — use sharp carbide or coated HSS, generous flood coolant, and expect fast tool wear; thin strip is normally punched or laser/EDM cut rather than machined.
Can Silicon Steel be welded?
With care — weldability is rated fair (45/100). Weldable by TIG/laser/resistance after stripping core-plate, but the HAZ grows coarse or oxidized and raises core loss — keep welds off the flux path or stress-relief anneal afterwards.
What surface finishes work on Silicon Steel?
Normally used as supplied with inorganic/organic core-plate (C-3/C-5/C-6) or phosphate insulation; bare edges need varnish, oil or paint since the steel rusts readily. Not anodizable.
Can Silicon Steel be formed, bent or molded?
Fully processed strip stamps and bends well with sharp, well-maintained tooling (clearance ~5 % of thickness); high-Si and grain-oriented grades are notch-sensitive and crack on tight bends.
What is the maximum service temperature of Silicon Steel?
Silicon Steel 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 Silicon Steel Annealed and Silicon Steel-SRA?
Annealed is the default condition — default stocked condition: magnetic properties already developed, ready to punch and stack without further annealing. SRA: apply after punching, bending or slitting to recover permeability and remove the loss penalty from cut edges and burrs. Yield strength is 320 MPa in Annealed versus 300 MPa in SRA.
How much does Silicon Steel cost?
Silicon Steel is a premium-cost steel ($$$), cheaper than about 62% 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 Silicon Steel?
Yes — Silicon Steel 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
- ASTM A677 — Nonoriented Electrical Steel Fully Processed Types — ASTM (2020)
- ASTM A683 — Nonoriented Electrical Steel Semiprocessed Types — ASTM (2019)
- ASTM A876 — Flat-Rolled, Grain-Oriented, Silicon-Iron, Fully Processed Types — ASTM (2019)
- IEC 60404-8-4 — Cold-rolled non-oriented electrical steel sheet and strip — IEC (2013)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels (Soft Magnetic Materials) — ASM International (1990)
- Selection of Electrical Steels for Magnetic Cores — AK Steel / Cleveland-Cliffs (2019)
- Electrical steel product catalogue (NGO / GO / Hi-B) — Baosteel (2023)
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.