Steel M103-27N-SRA
Heat-treated state
SRA = stress-relief annealed after slitting/cutting
Choose after shearing, punching or core winding to recover the cutting-induced loss increase and restore guaranteed magnetics.
Values for the SRA condition
What is M103-27N-SRA?
M103-27N-SRA is M103-27N heat treated to SRA — choose after shearing, punching or core winding to recover the cutting-induced loss increase and restore guaranteed magnetics. M103-27N-SRA has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 86% of steel grades. Elongation at break is 14% and the elastic modulus is 120 GPa (17.4 Msi). M103-27N-SRA 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
- Low stiffness — 120 GPa (17.4 Msi), worse than 99% 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
- 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
M103-27N-SRA properties
Typical room-temperature values for M103-27N-SRA; 5 are specific to this condition. Other listed values are M103-27N reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
M103-27N-SRA 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
M103-27N-SRA has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 86% of steel grades. Elongation at break is 14% and the elastic modulus is 120 GPa (17.4 Msi).
Thermal6
M103-27N-SRA 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 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
M103-27N-SRA conducts electricity at 3.6 % IACS, worse than 85% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (20/100), better than 87% of steel grades.
Sustainability4
Producing a kilogram of M103-27N-SRA takes about 33 MJ of energy and emits 2.6 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 15%.
Manufacturability7
M103-27N-SRA's machinability is fair (35/100, worse than 84% of steel grades); weldability poor (30/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with M103-27N-SRA
Is M103-27N easy to machine?
Do not machine conventionally — slit, shear, punch or laser/EDM cut with sharp, carbide or coated tooling; keep burr <10 µm and expect abrasive wear from the ceramic/phosphate coating.
Can M103-27N be welded?
Resistance or laser welding of coil joints only; any weld or heat-affected zone locally destroys the Goss texture and raises core loss, so avoid welds in the flux path.
Can M103-27N be formed, bent or molded?
Formability is limited and highly directional — use for flat stacked or wound cores with generous bend radii; all cutting introduces stress that should be removed by an 800 °C stress-relief anneal.
What surface finishes work on M103-27N?
Supplied ready-coated with an inorganic phosphate (C-5 type) film; do not paint, plate or anodise — protect from moisture and handle by edges to avoid coating damage.
M103-27N 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 – 3.3 | 3.1 |
| Cafter decarburisation annealing | ≤ 0.01 | 0 |
| Mn | 0.03 – 0.15 | 0.08 |
| Alacid-soluble Al; AlN inhibitor typical of Hi-B route | 0.02 – 0.04 | 0.03 |
| Ninhibitor former, removed in final anneal | ≤ 0.01 | 0.01 |
| S | ≤ 0.01 | 0 |
| P | ≤ 0.02 | 0.01 |
| Cuprocess-dependent inhibitor addition | ≤ 0.6 | 0.2 |
| Fe | balance |
M103-27N-SRA — frequently asked
What is M103-27N-SRA used for?
M103-27N-SRA is typically used for EHV power transformer cores, high-efficiency distribution transformer cores, wound and toroidal transformer cores, shunt reactor cores, low-noise transformer cores and instrument transformer cores. In short: highest-permeability Hi-B grade; lowest core loss available; higher cost per tonne.
What is the yield strength of M103-27N-SRA?
M103-27N-SRA has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 86% of steel grades.
Is M103-27N-SRA easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of steel grades). Do not machine conventionally — slit, shear, punch or laser/EDM cut with sharp, carbide or coated tooling; keep burr <10 µm and expect abrasive wear from the ceramic/phosphate coating.
Can M103-27N-SRA be welded?
Not readily — weldability is rated poor (30/100). Resistance or laser welding of coil joints only; any weld or heat-affected zone locally destroys the Goss texture and raises core loss, so avoid welds in the flux path.
What surface finishes work on M103-27N-SRA?
Supplied ready-coated with an inorganic phosphate (C-5 type) film; do not paint, plate or anodise — protect from moisture and handle by edges to avoid coating damage.
Can M103-27N-SRA be formed, bent or molded?
Formability is limited and highly directional — use for flat stacked or wound cores with generous bend radii; all cutting introduces stress that should be removed by an 800 °C stress-relief anneal.
What is the maximum service temperature of M103-27N-SRA?
M103-27N-SRA 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.
Sources
- EN 10107 — Grain-oriented electrical steel strip and sheet delivered in the fully processed state — CEN (2014)
- ASTM A876 / A976 — Grain-oriented electrical steel and insulating coatings — ASTM International (2019)
- High-permeability grain-oriented electrical steel product data (0.23–0.30 mm grades) — European/Asian GO steel producers (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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.