Steel E3404
GOST E3404 (Э3404)
Э3404 is a grain-oriented Fe-3%Si electrical steel to GOST practice, offered in 0.27, 0.30 and 0.35 mm gauges with a forsterite glass film plus phosphate insulating top coat, and also in stress-relief-annealed and uncoated conditions.
Reference datasheet — E3404 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
E3404 tempers and conditions
E3404 is supplied in one standard condition, SRA.
Supply forms, finishes and certifications
Ways E3404 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
0.27-ET | 0.27 mm strip, mill insulating coating | Surface finish |
0.30-ET | 0.30 mm strip, mill insulating coating | Surface finish |
0.35-ETDefault | 0.35 mm strip, mill insulating coating (ЭТ), as-supplied | Surface finish |
UNC | Uncoated / coating-stripped strip | Surface finish |
What is E3404?
Э3404 is a grain-oriented Fe-3%Si electrical steel to GOST practice, offered in 0.27, 0.30 and 0.35 mm gauges with a forsterite glass film plus phosphate insulating top coat, and also in stress-relief-annealed and uncoated conditions. It is bought for transformer and reactor laminations where the Goss texture gives low loss along the rolling direction. Yield strength is 310 MPa, tensile 350 MPa, elongation about 10 %, formability low, and service limited to roughly 200 °C. EN 10107 grades such as M140-30P are the nearest specification when GOST material is not available. E3404 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). E3404 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 350 MPa (50.8 ksi) — weaker than 83% of steel grades. Elongation at break is 10% and the elastic modulus is 115 GPa (16.7 Msi).
What is E3404 used for?
- Transformer cores
- Reactor cores
- Distribution transformer laminations
- Wound (toroidal) cores
- Instrument transformer cores
- Welding transformer cores
- Magnetic shielding laminations
Limitations
- Low stiffness — 115 GPa (16.7 Msi), worse than 100% of steel grades
- Hard to polish — 40/100, worse than 96% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
- Poor heat conductor — 24 W/m·K (13.9 BTU/hr·ft·°F), worse than 90% of steel grades
E3404 properties
Typical room-temperature values; bars are the position among steel grades.
Physical3
E3404 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
E3404 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 350 MPa (50.8 ksi) — weaker than 83% of steel grades. Elongation at break is 10% and the elastic modulus is 115 GPa (16.7 Msi).
Thermal6
E3404 is rated for continuous service to 200°C (392 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), worse than 90% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
E3404 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 E3404 takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 15%.
Manufacturability7
E3404's machinability is fair (35/100, worse than 84% of steel grades); weldability poor (30/100); formability fair (35/100).
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. E3404 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with E3404
Is E3404 easy to machine?
Blank by precision punching or laser/EDM only where loss penalty is acceptable; carbide or coated tooling is required because the ceramic coating is highly abrasive and burrs shortcut laminations.
Can E3404 be welded?
TIG/laser tack welding of stack edges is possible but the HAZ loses its Goss texture and coating, raising local loss — avoid welds crossing the flux path.
Can E3404 be formed, bent or molded?
Limited to slitting, shearing and gentle wound-core bending; the strip is notch-sensitive and any plastic strain must be removed by an 800 °C stress-relief anneal.
E3404 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 | 2.8 – 3.4 | 3.1 |
| Cafter decarburizing anneal | ≤ 0.01 | 0 |
| Mnwith S forms MnS inhibitor | 0.05 – 0.25 | 0.12 |
| Sinhibitor former, residual kept low | ≤ 0.01 | 0.01 |
| P | ≤ 0.03 | 0.01 |
| AlAlN inhibitor in HiB route | 0.01 – 0.04 | 0.03 |
| N | ≤ 0.01 | 0.01 |
| Cu | ≤ 0.3 | 0.1 |
| Fe | balance | — |
What surface finishes work on E3404?
Supplied with a forsterite (glass film) plus phosphate insulating top coat; do not shot-blast or pickle, touch up cut edges with core-plate varnish before oil immersion.
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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel E3404 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- GOST
- Э3404
How much does E3404 cost?
E3404 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
E3404 — frequently asked
What is E3404 used for?
E3404 is typically used for transformer cores, reactor cores, distribution transformer laminations, wound (toroidal) cores, instrument transformer cores and welding transformer cores. In short: GOST grain-oriented grade; multiple lamination gauges stocked; notch-sensitive, low formability.
What is the yield strength of E3404?
E3404 has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 350 MPa (50.8 ksi) — weaker than 83% of steel grades.
Is E3404 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of steel grades). Blank by precision punching or laser/EDM only where loss penalty is acceptable; carbide or coated tooling is required because the ceramic coating is highly abrasive and burrs shortcut laminations.
Can E3404 be welded?
Not readily — weldability is rated poor (30/100). TIG/laser tack welding of stack edges is possible but the HAZ loses its Goss texture and coating, raising local loss — avoid welds crossing the flux path.
What surface finishes work on E3404?
Supplied with a forsterite (glass film) plus phosphate insulating top coat; do not shot-blast or pickle, touch up cut edges with core-plate varnish before oil immersion.
Can E3404 be formed, bent or molded?
Limited to slitting, shearing and gentle wound-core bending; the strip is notch-sensitive and any plastic strain must be removed by an 800 °C stress-relief anneal.
What is the maximum service temperature of E3404?
E3404 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does E3404 cost?
E3404 is a standard-cost steel ($$), 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.
Sources
- ГОСТ 21427.1-83 — Сталь электротехническая холоднокатаная анизотропная тонколистовая — Gosstandart (1983)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (magnetically soft materials) — ASM International (1990)
- Grain-oriented electrical steel strip datasheets (CGO/HiB grades) — Baosteel / NLMK VIZ-Stal (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.