Steel CRGO
CRGO is a cold-rolled Fe–3%Si electrical steel whose Goss (110)[001] texture is developed by controlled hot rolling, cold rolling and high-temperature box annealing, giving extremely low core loss and high permeability along the rolling direction.
Values for the Annealed condition
CRGO tempers and conditions
CRGO is supplied in 3 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
High-permeability grain oriented | Choose for lowest core loss and highest induction (e.g. 30Q120/27QG100 class) in energy-efficient distribution and power transformers; mechanical properties as annealed. | 300 | 340 | 8 | 170 HB | 3.5 % IACS |
AnnealedDefault fully processed (decarburized + high-temperature box annealed, C-5 coated) | Standard commercial condition: magnetic properties and coating are final, use as-slit/as-punched with only a light stress-relief anneal after cutting. | 305 | 345 | 10 | 170 HB | 3.6 % IACS |
as final cold rolled strip, before decarburization/secondary recrystallization | Semi-finished mill condition (or customer-supplied hard strip): high strength and hardness but poor magnetic properties — must be decarburized/high-temperature annealed before use as a core. | 570 | 650 | 3 | 26 HRC | 3.5 % IACS |
Supply forms, finishes and certifications
Ways CRGO is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Domain Refined | Laser/mechanically scribed HiB strip | Surface finish |
What is CRGO?
CRGO is a cold-rolled Fe–3%Si electrical steel whose Goss (110)[001] texture is developed by controlled hot rolling, cold rolling and high-temperature box annealing, giving extremely low core loss and high permeability along the rolling direction. It is the standard core material for power and distribution transformers, reactors and large-machine laminations, normally supplied fully processed with an inorganic (C-5/C-6) insulating coating in 0.18–0.35 mm strip. Limits are strong magnetic and mechanical anisotropy (properties collapse off the rolling direction), brittleness from the silicon content, low corrosion resistance of cut edges, and loss of magnetic quality if the sheet is welded, heavily formed or heated above the coating/anneal window. CRGO 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). CRGO has a yield strength of 305 MPa (44.2 ksi) and a tensile strength of 345 MPa (50 ksi) — weaker than 84% of steel grades. Elongation at break is 10% and the elastic modulus is 125 GPa (18.1 Msi).
What is CRGO used for?
- Power transformer cores
- Distribution transformer cores
- Wound and stacked core laminations
- Reactor and choke cores
- Instrument and current transformer cores
- Large rotating-machine laminations
- Magnetic shielding sheet
Limitations
- Low stiffness — 125 GPa (18.1 Msi), worse than 99% of steel grades
- Low fracture toughness — 30 MPa·√m (27.3 ksi·√in), worse than 96% of steel grades
- 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
- Limited ductility — 10%, worse than 91% of steel grades
CRGO properties
Typical room-temperature values for CRGO-Annealed; bars are the position among steel grades.
Physical3
CRGO 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).
Mechanical16
CRGO has a yield strength of 305 MPa (44.2 ksi) and a tensile strength of 345 MPa (50 ksi) — weaker than 84% of steel grades. Elongation at break is 10% and the elastic modulus is 125 GPa (18.1 Msi).
Thermal6
CRGO 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
CRGO conducts electricity at 3.6 % IACS, worse than 85% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (18/100), better than 83% of steel grades.
Sustainability4
Producing a kilogram of CRGO takes about 40 MJ of energy and emits 2.6 kg of CO₂ — more than 91% of steel grades. Typical recycled content is 15%.
Manufacturability7
CRGO's machinability is fair (45/100, worse than 65% of steel grades); weldability poor (30/100); formability poor (30/100).
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. CRGO is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CRGO
Is CRGO easy to machine?
Normally slit, punched, guillotined or laser/EDM cut rather than machined; the ceramic-like coating and Si content are abrasive, so use carbide/coated tooling and sharp, well-maintained dies to avoid burrs that short laminations.
Can CRGO be welded?
TIG/laser welding is possible for core clamping tabs but locally destroys texture, coating and interlaminar insulation and raises core loss — keep welds off the flux path.
Can CRGO be formed, bent or molded?
Formability is limited and highly anisotropic; restrict to shearing, slitting and gentle radii along the rolling direction, then stress-relief anneal (~800 °C, decarburizing-free atmosphere) to recover punching-induced loss.
Manufacturability
The process limits FabDigit applies to CRGO. Every CRGO part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
Sheet metal
| Formability | Better30 / 100 |
|---|---|
| Weldability | Poor30 / 100 |
| Bendable | Yes |
CRGO 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 |
|---|---|---|
| Siraises resistivity, lowers eddy-current loss | 2.9 – 3.4 | 3.1 |
| Cafter decarburization anneal | ≤ 0.01 | 0 |
| Mn | 0.03 – 0.2 | 0.1 |
| SMnS inhibitor in CGO route | ≤ 0.01 | 0 |
| P | ≤ 0.03 | 0.01 |
| AlAlN inhibitor in HiB route | ≤ 0.04 | 0.03 |
| N | ≤ 0.01 | 0.01 |
| Cuinhibitor addition in some HiB routes | ≤ 0.6 | 0.1 |
| Fe | balance |
What surface finishes work on CRGO?
Supplied ready-coated (C-5/C-6 phosphate-type insulating layer); do not pickle or blast; protect cut edges with varnish, oil or core-plate paint against rust.
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 CRGO in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- Grain Oriented Silicon Steel
How much does CRGO cost?
CRGO 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.
CRGO — frequently asked
What is CRGO used for?
CRGO is typically used for power transformer cores, distribution transformer cores, wound and stacked core laminations, reactor and choke cores, instrument and current transformer cores and large rotating-machine laminations. In short: grain-oriented electrical coil.
What is the yield strength of CRGO?
CRGO has a typical yield strength of 305 MPa (44.2 ksi) and a tensile strength of 345 MPa (50 ksi) — weaker than 84% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is CRGO easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Normally slit, punched, guillotined or laser/EDM cut rather than machined; the ceramic-like coating and Si content are abrasive, so use carbide/coated tooling and sharp, well-maintained dies to avoid burrs that short laminations.
Can CRGO be welded?
Not readily — weldability is rated poor (30/100). TIG/laser welding is possible for core clamping tabs but locally destroys texture, coating and interlaminar insulation and raises core loss — keep welds off the flux path.
What surface finishes work on CRGO?
Supplied ready-coated (C-5/C-6 phosphate-type insulating layer); do not pickle or blast; protect cut edges with varnish, oil or core-plate paint against rust.
Can CRGO be formed, bent or molded?
Formability is limited and highly anisotropic; restrict to shearing, slitting and gentle radii along the rolling direction, then stress-relief anneal (~800 °C, decarburizing-free atmosphere) to recover punching-induced loss.
What is the maximum service temperature of CRGO?
CRGO 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 CRGO Annealed and CRGO-HiB?
Annealed is the default condition — standard commercial condition: magnetic properties and coating are final, use as-slit/as-punched with only a light stress-relief anneal after cutting. HiB: choose for lowest core loss and highest induction (e.g. 30Q120/27QG100 class) in energy-efficient distribution and power transformers; mechanical properties as annealed. Yield strength is 305 MPa in Annealed versus 300 MPa in HiB.
How much does CRGO cost?
CRGO 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 CRGO?
Yes — CRGO 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 A876 — Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel, Fully Processed Types — ASTM International (2018)
- IEC 60404-8-7 — Magnetic materials: grain-oriented steel sheet and strip — IEC (2020)
- ASM Handbook Vol. 2 — Properties of Magnetically Soft Materials — ASM International (1990)
- Grain-oriented electrical steel (TRAN-COR H / conventional GO) product data — Cleveland-Cliffs (AK Steel) (2022)
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.