Steel 27Q120
EN 27Q120
27Q120 is a 0.27 mm grain-oriented silicon steel with about 3 % Si and a C-5 phosphate insulating film, supplied as coated coil, slit strip, sheared laminations or in the stress-relief-annealed condition.
Reference datasheet — 27Q120 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.
27Q120 tempers and conditions
27Q120 is supplied in one standard condition, SRA.
Supply forms, finishes and certifications
Ways 27Q120 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
COIL-C5Default | Coil, C-5 inorganic insulating coating | Supply form |
LAM-SHEARED | Sheared / punched laminations, as-cut | Surface finish |
SLIT | Slit strip / longitudinally cut coil | Surface finish |
What is 27Q120?
27Q120 is a 0.27 mm grain-oriented silicon steel with about 3 % Si and a C-5 phosphate insulating film, supplied as coated coil, slit strip, sheared laminations or in the stress-relief-annealed condition. The thinner gauge lowers eddy-current loss compared with 0.30 mm grades, so it is used in higher-efficiency power and instrument transformer cores. Properties are directional and the strip is brittle: 12 % elongation, 150 °C maximum service temperature and a corrosion resistance score of 28 that depends on the coating remaining intact. 30Q140 is the lower-cost alternative where loss targets allow. 27Q120 has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 97% of steel grades. It melts at 1,470°C (2,678 °F). 27Q120 has a yield strength of 315 MPa (45.7 ksi) and a tensile strength of 355 MPa (51.5 ksi) — weaker than 82% of steel grades. Elongation at break is 12% and the elastic modulus is 115 GPa (16.7 Msi).
What is 27Q120 used for?
- Power transformer cores
- Instrument transformer cores
- Distribution transformer laminations
- Step-lap stacked core assemblies
- Wound toroidal cores
- Slit strip for core winding
Advantages
- Good corrosion resistance — 25/100, better than 92% of steel grades
Limitations
- Low stiffness — 115 GPa (16.7 Msi), worse than 100% of steel grades
- Hard to polish — 30/100, worse than 100% of steel grades
- Limited service temperature — 150°C (302 °F), worse than 99% of steel grades
- Poor heat conductor — 22 W/m·K (12.7 BTU/hr·ft·°F), worse than 93% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 87% of steel grades
27Q120 properties
Typical room-temperature values; bars are the position among steel grades.
Physical3
27Q120 has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 97% of steel grades. It melts at 1,470°C (2,678 °F).
Mechanical12
27Q120 has a yield strength of 315 MPa (45.7 ksi) and a tensile strength of 355 MPa (51.5 ksi) — weaker than 82% of steel grades. Elongation at break is 12% and the elastic modulus is 115 GPa (16.7 Msi).
Thermal6
27Q120 is rated for continuous service to 150°C (302 °F). It conducts heat at 22 W/m·K (12.7 BTU/hr·ft·°F), worse than 93% of steel grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
27Q120 conducts electricity at 3.6 % IACS, worse than 85% of steel grades.
Chemical & Environmental2
Corrosion resistance is poor (25/100), better than 92% of steel grades.
Sustainability4
Producing a kilogram of 27Q120 takes about 34 MJ of energy and emits 2.6 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 15%.
Manufacturability7
27Q120'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. 27Q120 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 27Q120
Is 27Q120 easy to machine?
Not machined conventionally — blank by precision shearing, guillotine or carbide/PCD punching with tight clearance and sharp tools; burr height should stay under ~20 µm to avoid interlaminar shorts.
Can 27Q120 be welded?
Avoid welding in the magnetic path; any TIG/laser tack destroys the Goss texture and coating locally — use clamping, banding or edge tack welds outside the flux path.
Can 27Q120 be formed, bent or molded?
3 % Si makes the strip brittle: only slitting, shearing, mitre cutting and large-radius winding are practical; no deep drawing or tight bending.
27Q120 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 |
|---|---|---|
| Sigives ~48 µΩ·cm resistivity, lowers eddy-current loss | 2.9 – 3.3 | 3.1 |
| Cafter decarburizing anneal; ≤0.003 % in final product | ≤ 0.01 | 0 |
| Mn | 0.03 – 0.2 | 0.1 |
| SMnS used as inhibitor, largely removed in high-temperature anneal | ≤ 0.01 | 0.01 |
| P | ≤ 0.03 | 0.02 |
| AlAlN inhibitor route | ≤ 0.04 | 0.02 |
| N | ≤ 0.01 | 0 |
| Cuinhibitor addition in some mill routes | ≤ 0.6 | 0.1 |
| Fe | balance |
What surface finishes work on 27Q120?
Supplied ready-coated with a C-5 type phosphate insulating film; if cutting or annealing damages it, re-coat or varnish edges, and stress-relief anneal at ~800 °C in dry N₂/H₂ before re-coating.
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
How much does 27Q120 cost?
27Q120 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
27Q120 — frequently asked
What is 27Q120 used for?
27Q120 is typically used for power transformer cores, instrument transformer cores, distribution transformer laminations, step-lap stacked core assemblies, wound toroidal cores and slit strip for core winding. In short: lower loss than 30Q140; thin 0.27 mm grain-oriented; shear and wind only.
What is the yield strength of 27Q120?
27Q120 has a typical yield strength of 315 MPa (45.7 ksi) and a tensile strength of 355 MPa (51.5 ksi) — weaker than 82% of steel grades.
Is 27Q120 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of steel grades). Not machined conventionally — blank by precision shearing, guillotine or carbide/PCD punching with tight clearance and sharp tools; burr height should stay under ~20 µm to avoid interlaminar shorts.
Can 27Q120 be welded?
Not readily — weldability is rated poor (30/100). Avoid welding in the magnetic path; any TIG/laser tack destroys the Goss texture and coating locally — use clamping, banding or edge tack welds outside the flux path.
What surface finishes work on 27Q120?
Supplied ready-coated with a C-5 type phosphate insulating film; if cutting or annealing damages it, re-coat or varnish edges, and stress-relief anneal at ~800 °C in dry N₂/H₂ before re-coating.
Can 27Q120 be formed, bent or molded?
3 % Si makes the strip brittle: only slitting, shearing, mitre cutting and large-radius winding are practical; no deep drawing or tight bending.
What is the maximum service temperature of 27Q120?
27Q120 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 27Q120 cost?
27Q120 is a standard-cost steel ($$), 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
- IEC 60404-8-7 Magnetic materials — Specifications for grain-oriented steel sheet and strip — IEC (2020)
- Grain-oriented electrical steel product catalogue — Baosteel / (2023)
- 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; 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.