Steel M19
AISI/SAE M19
M19 is a fully processed non-oriented electrical steel in the AISI/ASTM A677 system (close to 50W470 / 50A470), alloyed with about 3 % silicon plus aluminium to give low core loss, high permeability and good punchability, typically stocked 0.35–0.64 mm thick with a C-5 insulating coating.
Values for the Annealed condition
M19 tempers and conditions
M19 is supplied in 2 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault fully processed (final annealed, C-5 coated) | Standard fully processed condition: magnetic properties are final, stamp laminations and use as-is. | 340 | 460 | 25 | 72 HRB | — |
as-rolled / temper-rolled, not final annealed | Pick when laminations will be stress-relief or decarburising annealed after blanking; higher strength and flatness, poorer as-supplied core loss. | 500 | 580 | 8 | 88 HRB | — |
What is M19?
M19 is a fully processed non-oriented electrical steel in the AISI/ASTM A677 system (close to 50W470 / 50A470), alloyed with about 3 % silicon plus aluminium to give low core loss, high permeability and good punchability, typically stocked 0.35–0.64 mm thick with a C-5 insulating coating. Engineers choose it for its loss-to-cost ratio and isotropic magnetic properties in stamped lamination stacks for small and medium motors, generators, transformers and reactors. The high silicon content makes the strip brittle and notch-sensitive, weldability (score 50) and corrosion resistance are moderate, and blanking stresses raise core loss, so stress-relief annealing is often needed after stamping. M19 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). M19 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 76% of steel grades. Elongation at break is 25% and the elastic modulus is 200 GPa (29 Msi).
What is M19 used for?
- Motor stator and rotor laminations
- Distribution transformer cores
- Generator and alternator laminations
- Reactor and choke cores
- Servo and stepper motor stacks
- Solenoid and relay cores
Advantages
- Forms and bends easily — 65/100, better than 81% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% 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 — 3.3 % IACS, worse than 86% of steel grades
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
M19 properties
Typical room-temperature values for M19-Annealed; bars are the position among steel grades.
Physical3
M19 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).
Mechanical12
M19 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 76% of steel grades. Elongation at break is 25% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
M19 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 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
M19 conducts electricity at 3.3 % IACS, worse than 86% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of M19 takes about 32 MJ of energy and emits 2.4 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 25%.
Manufacturability7
M19's machinability is fair (45/100, worse than 65% of steel grades); weldability fair (50/100); formability good (65/100).
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. M19 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with M19
Is M19 easy to machine?
Punching/blanking with sharp carbide tooling and tight clearance (~5 % of thickness) is the normal route; conventional machining is abrasive and burrs short adjacent laminations.
Can M19 be welded?
Only tack/laser stitch welding of stacks is normal — any weld or heat-affected zone locally raises core loss and can create interlaminar shorts.
Can M19 be formed, bent or molded?
Good punchability and moderate bendability; the 3 % Si makes it notch-sensitive, so avoid tight bend radii and stress-relieve (750–840 °C, inert/decarb atmosphere) after heavy forming.
Manufacturability
The process limits FabDigit applies to M19. Every M19 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
Sheet metal
| Formability | Better65 / 100 |
|---|---|
| Weldability | Poor50 / 100 |
| Bendable | Yes |
M19 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 | 2.8 – 3.4 | 3.15 |
| Alco-alloyed with Si to raise resistivity | 0.2 – 0.7 | 0.4 |
| Mn | 0.1 – 0.5 | 0.3 |
| Ckept ultra-low to avoid magnetic ageing | ≤ 0.01 | 0 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.01 | 0.01 |
| N | ≤ 0.01 | 0 |
| Fe | balance |
What surface finishes work on M19?
Supplied with C-5 inorganic/organic insulating coating; do not shot blast or pickle, and clean only with solvents before varnish impregnation of the stack.
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).
Plating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel M19 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 50W47050A470
How much does M19 cost?
M19 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
M19 — frequently asked
What is M19 used for?
M19 is typically used for motor stator and rotor laminations, distribution transformer cores, generator and alternator laminations, reactor and choke cores, servo and stepper motor stacks and solenoid and relay cores. In short: non-oriented electrical coil.
What is the yield strength of M19?
M19 has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 76% of steel grades. Strength varies by condition: see the 2 listed tempers.
Is M19 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Punching/blanking with sharp carbide tooling and tight clearance (~5 % of thickness) is the normal route; conventional machining is abrasive and burrs short adjacent laminations.
Can M19 be welded?
With care — weldability is rated fair (50/100). Only tack/laser stitch welding of stacks is normal — any weld or heat-affected zone locally raises core loss and can create interlaminar shorts.
What surface finishes work on M19?
Supplied with C-5 inorganic/organic insulating coating; do not shot blast or pickle, and clean only with solvents before varnish impregnation of the stack.
Can M19 be formed, bent or molded?
Good punchability and moderate bendability; the 3 % Si makes it notch-sensitive, so avoid tight bend radii and stress-relieve (750–840 °C, inert/decarb atmosphere) after heavy forming.
What is the maximum service temperature of M19?
M19 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does M19 cost?
M19 is a standard-cost steel ($$), 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.
Can FabDigit make parts in M19?
Yes — M19 is available for sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A677 — Nonoriented Electrical Steel Fully Processed Types — ASTM (2020)
- ASTM A683 — Nonoriented Electrical Steel Semiprocessed Types — ASTM (2019)
- ASTM A976 — Classification of Insulating Coatings for Electrical Steels — ASTM (2019)
- Selection of Electrical Steels for Magnetic Cores — AK Steel / Cleveland-Cliffs (2019)
- ASM Handbook Vol.1 — Properties of 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.