Steel M27
AISI/SAE M27
M27 is a non-oriented silicon steel covered by ASTM A677 and equivalent to the 50W600 designation, silicon-alloyed to raise resistivity and hold down eddy-current loss in stacked laminations.
Reference datasheet — M27 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.
M27 tempers and conditions
M27 is supplied in 3 conditions, soft to hard.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stress-relief annealed after punching | Use when punching/edge stresses have raised core loss; the anneal recovers magnetic performance at the cost of softening the laminations. | 280 | 420 | 33 | 147 HB | 3.8 % IACS |
Semi-processed, 0.64 mm | Heavy-gauge semi-processed coil for high-volume punched stators/rotors that are annealed in the assembly line. | 365 | 475 | 22 | 8 HRC | 3.8 % IACS |
Semi-processed, 0.47 mm | Choose when laminations are punched hard and then decarburize/grain-grow annealed by the customer to reach final magnetic quality. | 370 | 480 | 20 | 9 HRC | 3.8 % IACS |
Supply forms, finishes and certifications
Ways M27 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
C-0 | Mill finish, no applied insulating coating | Surface finish |
C-3 | Organic (enamel/varnish) insulating coating | Surface finish |
C-5 | Inorganic (phosphate-type) insulating coating, anneal-resistant | Surface finish |
FP-47Default | Fully processed, 0.47 mm (26 gauge), C-5 coated | Surface finish |
FP-50 | Fully processed, 0.50 mm | Surface finish |
FP-64 | Fully processed, 0.64 mm (24 gauge), C-5 coated | Surface finish |
What is M27?
M27 is a non-oriented silicon steel covered by ASTM A677 and equivalent to the 50W600 designation, silicon-alloyed to raise resistivity and hold down eddy-current loss in stacked laminations. It is supplied as slit coil and finished laminations in fully processed (FP) and semi-processed (SP) tempers, stress-relief annealed, and with C-0, C-3 or C-5 insulating coatings. Core loss is higher than M19, service is limited to about 200 °C, and any weld through the stack shorts laminations; move to M19 or a 0.35 mm gauge when efficiency, not lamination price, drives the design. M27 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 93% of steel grades. It melts at 1,500°C (2,732 °F). M27 has a yield strength of 315 MPa (45.7 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 82% of steel grades. Elongation at break is 28% and the elastic modulus is 200 GPa (29 Msi).
What is M27 used for?
- general-purpose motors
- ballasts
- small transformers
Advantages
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Poor heat conductor — 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 88% of steel grades
- Low electrical conductivity — 3.8 % IACS, worse than 84% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
- Low strength — 315 MPa (45.7 ksi), worse than 82% of steel grades
M27 properties
Typical room-temperature values; bars are the position among steel grades.
Physical3
M27 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 93% of steel grades. It melts at 1,500°C (2,732 °F).
Mechanical11
M27 has a yield strength of 315 MPa (45.7 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 82% of steel grades. Elongation at break is 28% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
M27 is rated for continuous service to 200°C (392 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 88% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
M27 conducts electricity at 3.8 % IACS, worse than 84% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (14/100), better than 70% of steel grades.
Sustainability4
Producing a kilogram of M27 takes about 34 MJ of energy and emits 2.5 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
M27's machinability is fair (45/100, worse than 65% of steel grades); weldability good (55/100); formability good (60/100).
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. M27 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with M27
Is M27 easy to machine?
Blank and punch rather than machine — the Si content is abrasive, so use carbide/PM tooling, tight die clearance (5–8 % of thickness) and frequent regrinds to control burrs that short laminations.
Can M27 be welded?
TIG/laser stack welding is possible but the weld and HAZ short the laminations and raise local loss; keep welds short, outside the flux path, or use interlock/bonding instead.
Can M27 be formed, bent or molded?
Excellent for flat blanking, interlocking and light bending; avoid deep drawing or tight bend radii (<2t) since silicon steel has limited ductility and notch sensitivity.
M27 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 |
|---|---|---|
| Siprincipal resistivity-raising addition; Si+Al ≈ 2.3–2.8 % | 1.8 – 2.6 | 2.3 |
| Alpart of the Si+Al loss-control balance | 0.15 – 0.6 | 0.35 |
| Mn | 0.1 – 0.5 | 0.3 |
| Cdecarburized in fully processed product | ≤ 0.01 | 0 |
| Psometimes added for strength/resistivity | ≤ 0.05 | 0.02 |
| S | ≤ 0.01 | 0.01 |
| N | ≤ 0.01 | 0 |
| Febalance; ASTM A677 specifies magnetic properties rather than a strict chemistry | balance |
What surface finishes work on M27?
Normally used with the mill C-3/C-5 insulating coating; bare edges rust, so varnish-dip, resin-encapsulate or paint assembled cores — no anodizing applies.
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 M27 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 50W600
How much does M27 cost?
M27 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
M27 — frequently asked
What is M27 used for?
M27 is typically used for general-purpose motors, ballasts and small transformers. In short: low-cost non-oriented lamination; higher core loss than M19; isotropic magnetic properties.
What is the yield strength of M27?
M27 has a typical yield strength of 315 MPa (45.7 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 82% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is M27 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Blank and punch rather than machine — the Si content is abrasive, so use carbide/PM tooling, tight die clearance (5–8 % of thickness) and frequent regrinds to control burrs that short laminations.
Can M27 be welded?
Yes — weldability is rated good (55/100). TIG/laser stack welding is possible but the weld and HAZ short the laminations and raise local loss; keep welds short, outside the flux path, or use interlock/bonding instead.
What surface finishes work on M27?
Normally used with the mill C-3/C-5 insulating coating; bare edges rust, so varnish-dip, resin-encapsulate or paint assembled cores — no anodizing applies.
Can M27 be formed, bent or molded?
Excellent for flat blanking, interlocking and light bending; avoid deep drawing or tight bend radii (<2t) since silicon steel has limited ductility and notch sensitivity.
What is the maximum service temperature of M27?
M27 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does M27 cost?
M27 is a budget-cost steel ($), cheaper than about 90% 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 A677 — Nonoriented Electrical Steel Fully Processed Types — ASTM International (2020)
- ASTM A683 — Nonoriented Electrical Steel Semiprocessed Types — ASTM International (2019)
- ASTM A976 — Classification of Insulating Coatings for Electrical Steels — ASTM International (2019)
- Non-Oriented Electrical Steels (M-15 … M-45) product data — Cleveland-Cliffs (formerly AK Steel) (2021)
- 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.