Steel M140-30P
M140-30P is a conventional grain-oriented Fe-3%Si electrical steel to EN 10107, 0.30 mm gauge, with a Goss texture aligned to the rolling direction and a C-5 or C-6 inorganic insulating coating.
Reference datasheet — M140-30P 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.
M140-30P tempers and conditions
M140-30P is supplied in one standard condition, SRA.
Supply forms, finishes and certifications
Ways M140-30P is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
AS-C5Default | As-supplied | Surface finish |
C6 | C-6 | Surface finish |
DR | Laser domain-refined (scribed) strip for stacked cores | Surface finish |
MDR | Mechanically/plasma scribed, heat-proof domain refinement for wound… | Surface finish |
What is M140-30P?
M140-30P is a conventional grain-oriented Fe-3%Si electrical steel to EN 10107, 0.30 mm gauge, with a Goss texture aligned to the rolling direction and a C-5 or C-6 inorganic insulating coating. It is used for stacked and wound distribution and power transformer cores, where loss and permeability along the rolling direction drive the design; slit coil, stress-relief-annealed and domain-refined (DR/MDR) conditions are stocked. The strip is brittle and anisotropic, with 10 % elongation and low formability, and service is limited to about 150 °C. High-permeability grades such as M103-27N are the next step up. M140-30P 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). M140-30P has a yield strength of 315 MPa (45.7 ksi) and a tensile strength of 335 MPa (48.6 ksi) — weaker than 82% of steel grades. Elongation at break is 10% and the elastic modulus is 120 GPa (17.4 Msi).
What is M140-30P used for?
- Distribution transformer cores
- Power transformer cores
- Wound (unicore) transformer cores
- Reactor and shunt cores
- Instrument transformer cores
- Welding transformer cores
- Magnetic shunts and shields
Advantages
- Good corrosion resistance — 22/100, better than 90% of steel grades
Limitations
- Low stiffness — 120 GPa (17.4 Msi), worse than 99% of steel grades
- Limited service temperature — 150°C (302 °F), worse than 99% of steel grades
- Hard to polish — 35/100, worse than 99% of steel grades
- Poor heat conductor — 21 W/m·K (12.1 BTU/hr·ft·°F), worse than 95% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
M140-30P properties
Typical room-temperature values; bars are the position among steel grades.
Physical3
M140-30P 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).
Mechanical11
M140-30P has a yield strength of 315 MPa (45.7 ksi) and a tensile strength of 335 MPa (48.6 ksi) — weaker than 82% of steel grades. Elongation at break is 10% and the elastic modulus is 120 GPa (17.4 Msi).
Thermal6
M140-30P is rated for continuous service to 150°C (302 °F). It conducts heat at 21 W/m·K (12.1 BTU/hr·ft·°F), worse than 95% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
M140-30P conducts electricity at 3.6 % IACS, worse than 85% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (22/100), better than 90% of steel grades.
Sustainability4
Producing a kilogram of M140-30P takes about 36 MJ of energy and emits 2.6 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 20%.
Manufacturability7
M140-30P's machinability is poor (30/100, worse than 89% 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. M140-30P is highlighted; hover a dot for its name, or open the interactive family chart.
Working with M140-30P
Is M140-30P easy to machine?
Normally only slit, sheared, punched or laser/EDM cut to lamination shape — the Fe-3Si and its glass film are highly abrasive, so carbide tooling with tight clearance and frequent regrinding is required to limit burrs.
Can M140-30P be welded?
Avoid welding through the stack; TIG/laser tack welds break the interlaminar insulation and locally destroy the Goss texture, raising core loss — use clamping, banding or bonding instead.
Can M140-30P be formed, bent or molded?
Strip is brittle and strongly anisotropic; keep bends and core-winding radii generous, cut with the rolling direction along the flux path, and stress-relief anneal at ~800 °C in a protective atmosphere after forming.
M140-30P 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 |
|---|---|---|
| Sitypical producer chemistry; EN 10107 specifies magnetic properties, not composition | 2.9 – 3.3 | 3.1 |
| Cafter decarburization annealing | ≤ 0.01 | 0 |
| Mn | 0.05 – 0.25 | 0.12 |
| SMnS/AlN inhibitors controlled in processing | ≤ 0.01 | 0 |
| Alacid-soluble Al for AlN inhibitor (HGO route) | ≤ 0.04 | 0.02 |
| N | ≤ 0.01 | 0 |
| P | ≤ 0.03 | 0.01 |
| Cuused by some producers as inhibitor-forming element | ≤ 0.6 | 0.1 |
| Fe | balance |
What surface finishes work on M140-30P?
Supplied ready-coated (C-5 phosphate/forsterite or C-6 composite); do not pickle, blast or paint over it — protect cut edges against rust and handle to avoid scratching the insulating film.
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 M140-30P cost?
M140-30P 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.
M140-30P — frequently asked
What is M140-30P used for?
M140-30P is typically used for distribution transformer cores, power transformer cores, wound (unicore) transformer cores, reactor and shunt cores, instrument transformer cores and welding transformer cores. In short: standard EN grain-oriented grade; low loss along rolling direction; brittle, poorly formable strip.
What is the yield strength of M140-30P?
M140-30P has a typical yield strength of 315 MPa (45.7 ksi) and a tensile strength of 335 MPa (48.6 ksi) — weaker than 82% of steel grades.
Is M140-30P easy to machine?
Not especially — machinability is rated poor (30/100, worse than 89% of steel grades). Normally only slit, sheared, punched or laser/EDM cut to lamination shape — the Fe-3Si and its glass film are highly abrasive, so carbide tooling with tight clearance and frequent regrinding is required to limit burrs.
Can M140-30P be welded?
Not readily — weldability is rated poor (30/100). Avoid welding through the stack; TIG/laser tack welds break the interlaminar insulation and locally destroy the Goss texture, raising core loss — use clamping, banding or bonding instead.
What surface finishes work on M140-30P?
Supplied ready-coated (C-5 phosphate/forsterite or C-6 composite); do not pickle, blast or paint over it — protect cut edges against rust and handle to avoid scratching the insulating film.
Can M140-30P be formed, bent or molded?
Strip is brittle and strongly anisotropic; keep bends and core-winding radii generous, cut with the rolling direction along the flux path, and stress-relief anneal at ~800 °C in a protective atmosphere after forming.
What is the maximum service temperature of M140-30P?
M140-30P 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 M140-30P cost?
M140-30P 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
- EN 10107 — Grain-oriented electrical steel strip and sheet delivered in the fully processed state — CEN (2014)
- GB/T 2521.2 — Cold-rolled grain-oriented electrical steel strip (30Q140 class) — SAC (2016)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (magnetically soft materials) — ASM International (1990)
- Grain-oriented electrical steel product data (0.30 mm high-permeability grades) — GOES producers (e.g. thyssenkrupp Electrical Steel, Nippon Steel, 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.