Steel M-6
UNS T11306
M-6 is a conventional grain-oriented silicon steel to ASTM A876 (UNS T11306), cold rolled and annealed to a Goss texture that aligns easy magnetisation with the rolling direction and minimises hysteresis loss when flux follows that axis.
Reference datasheet — M-6 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.
M-6 tempers and conditions
M-6 is supplied in 4 conditions, soft to hard.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Laminations stress-relief annealed after shearing/punching | Pick when blanks are punched, bent or tightly wound: the anneal recovers the core loss and permeability lost to cutting strain, at the cost of slightly lower strength. | 295 | 335 | 12 | 160 HB | 3.6 % IACS |
Domain-refined (laser/mechanically scribed) 0.35 mm grain-oriented strip | Choose for lowest core loss in wound or stacked cores that will NOT be stress-relief annealed — the anneal erases the scribing benefit. | 315 | 350 | 7 | 172 HB | 3.6 % IACS |
Annealed | Soft supply condition of the cobalt-moly high-speed steel alias (0.8 C-4 W-5 Mo-4 Cr-1.5 V-12 Co) for machining tool blanks before hardening; not an electrical-steel condition. | 560 | 850 | 12 | 240 HB | 21 W/m·K |
Hardened & triple tempered | Service condition of the M6 HSS alias — austenitize ~1190-1210 °C, quench, temper 3× at 550-560 °C; chosen when 12 % Co red-hardness is needed for heavy-duty cutting. | 2,100 | 0.5 | 65 HRC | 24 W/m·K |
Supply forms, finishes and certifications
Ways M-6 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FPDefault | Fully processed CGO, decarburized, high-temperature annealed, C-5 coated | Surface finish |
What is M-6?
M-6 is a conventional grain-oriented silicon steel to ASTM A876 (UNS T11306), cold rolled and annealed to a Goss texture that aligns easy magnetisation with the rolling direction and minimises hysteresis loss when flux follows that axis. It is bought as slit coil, mitre-cut laminations and wound cores carrying an inorganic phosphate/forsterite C-5 coating, in fully processed, stress-relief annealed and domain-refined conditions. Properties are strongly directional and ductility is low (8 % elongation, 350 MPa tensile), so cross-grain bending and welding through the stack must be avoided; Hi-B M-3 gives lower loss at higher cost. M-6 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). M-6 has a yield strength of 315 MPa (45.7 ksi) and a tensile strength of 350 MPa (50.8 ksi) — weaker than 82% of steel grades. Elongation at break is 8% and the elastic modulus is 120 GPa (17.4 Msi).
What is M-6 used for?
- Distribution transformer cores
- Power transformer cores
- Wound C-cores and toroidal cores
- Reactor and choke cores
- Current transformer cores
- Instrument transformer laminations
Limitations
- Low stiffness — 120 GPa (17.4 Msi), worse than 99% of steel grades
- Limited ductility — 8%, worse than 95% 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
- Low electrical conductivity — 3.6 % IACS, worse than 85% of steel grades
M-6 properties
Typical room-temperature values; bars are the position among steel grades.
Physical3
M-6 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
M-6 has a yield strength of 315 MPa (45.7 ksi) and a tensile strength of 350 MPa (50.8 ksi) — weaker than 82% of steel grades. Elongation at break is 8% and the elastic modulus is 120 GPa (17.4 Msi).
Thermal6
M-6 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
M-6 conducts electricity at 3.6 % IACS, worse than 85% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of M-6 takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 20%.
Manufacturability6
M-6's machinability is fair (35/100, worse than 84% of steel grades); weldability fair (40/100); 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. M-6 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with M-6
Is M-6 easy to machine?
Best processed by precision slitting, punching and laser/EDM cutting with carbide or coated tooling — the ceramic-like C-5 coating is abrasive and thermal cut edges must be de-burred; the M6 HSS variant is machined only in the annealed state and ground after hardening.
Can M-6 be welded?
TIG/laser tacking of core clamps is possible but any weld or heat-affected zone locally destroys the Goss texture and short-circuits laminations, so joints are kept off the flux path.
Can M-6 be formed, bent or molded?
Handle as a springy, notch-sensitive strip: shear along the rolling direction, keep bend radii generous, and stress-relief anneal at ~800 °C in inert atmosphere when strain is significant.
M-6 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 decarburization anneal; higher in as-rolled strip | ≤ 0.01 | 0 |
| Mnwith S forms MnS grain-growth inhibitor | 0.03 – 0.2 | 0.08 |
| S | ≤ 0.01 | 0 |
| AlAlN inhibitor route | ≤ 0.03 | 0.02 |
| N | ≤ 0.01 | 0.01 |
| P | ≤ 0.02 | 0.01 |
| Cuprocess-dependent inhibitor addition | ≤ 0.3 | 0.1 |
| Fe | balance |
What surface finishes work on M-6?
Supplied with an inorganic phosphate/forsterite (C-5) insulating coating that also gives light rust protection; do not anodize (ferrous), and re-coat or oil any bare sheared edges.
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 M-6 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- T11306
How much does M-6 cost?
M-6 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.
M-6 — frequently asked
What is M-6 used for?
M-6 is typically used for distribution transformer cores, power transformer cores, wound C-cores and toroidal cores, reactor and choke cores, current transformer cores and instrument transformer laminations. In short: standard grain-oriented transformer steel; lowest loss along rolling direction; lower cost than Hi-B.
What is the yield strength of M-6?
M-6 has a typical yield strength of 315 MPa (45.7 ksi) and a tensile strength of 350 MPa (50.8 ksi) — weaker than 82% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is M-6 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of steel grades). Best processed by precision slitting, punching and laser/EDM cutting with carbide or coated tooling — the ceramic-like C-5 coating is abrasive and thermal cut edges must be de-burred; the M6 HSS variant is machined only in the annealed state and ground after hardening.
Can M-6 be welded?
With care — weldability is rated fair (40/100). TIG/laser tacking of core clamps is possible but any weld or heat-affected zone locally destroys the Goss texture and short-circuits laminations, so joints are kept off the flux path.
What surface finishes work on M-6?
Supplied with an inorganic phosphate/forsterite (C-5) insulating coating that also gives light rust protection; do not anodize (ferrous), and re-coat or oil any bare sheared edges.
Can M-6 be formed, bent or molded?
Handle as a springy, notch-sensitive strip: shear along the rolling direction, keep bend radii generous, and stress-relief anneal at ~800 °C in inert atmosphere when strain is significant.
What is the maximum service temperature of M-6?
M-6 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 M-6 cost?
M-6 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
- ASTM A876 — Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel, Fully Processed Types — ASTM International (2018)
- ASTM A677 / A343 / A34 (electrical steel test and designation practice) — ASTM International (2020)
- Grain-oriented electrical steel product data (M-4/M-5/M-6 types) — Cleveland-Cliffs (former AK Steel) (2021)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels, and High-Performance Alloys (magnetically soft materials; high-speed tool steels) — ASM International (1990)
- ASTM A600 — Tool Steel High Speed (AISI M6, UNS T11306) — ASTM International (2016)
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.