Steel SCMn3
JIS SCMn3
SCMn3 is a medium-strength manganese alloy steel casting under JIS G5111, available as-cast, annealed, normalized, N+T, quenched and tempered (including a 28-32 HRC class) and stress relieved.
Reference datasheet — SCMn3 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.
Values for the N+T condition
SCMn3 tempers and conditions
SCMn3 is supplied in 7 conditions, soft to hard. N+T is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Choose when maximum machinability and dimensional stability matter more than strength, or before further heat treatment. | 320 | 580 | 22 | 170 HB | — |
As fabricated | Only for non-critical parts or as an intermediate state before heat treatment; coarse dendritic structure and low toughness. | 340 | 620 | 10 | 195 HB | 8 % IACS |
Normalized | Refines the as-cast grain and gives uniform properties at low cost; used where the tempered condition is not required. | 420 | 700 | 16 | 210 HB | 8 % IACS |
Stress relieved | Sub-critical soak (550–650 °C) to remove casting/welding residual stress with minimal change to mechanical properties. | 420 | 680 | 17 | 200 HB | 8 % IACS |
N+TDefault Normalized and tempered | Default supply condition: meets the JIS G5111 SCMn3 minima (640 MPa UTS / 370 MPa YS / 13 % elongation) with balanced toughness in medium sections. | 430 | 690 | 17 | 205 HB | — |
Quenched and tempered | Pick for the highest strength and best toughness combination in sections up to ~100 mm — gears, links, heavy machine frames. | 620 | 830 | 15 | 25 HRC | — |
Quenched and tempered to a specified hardness band | Ordered when a hardness window is contractually required (wear surfaces, induction-hardened bases, gear blanks). | 760 | 950 | 13 | 30 HRC | — |
What is SCMn3?
SCMn3 is a medium-strength manganese alloy steel casting under JIS G5111, available as-cast, annealed, normalized, N+T, quenched and tempered (including a 28-32 HRC class) and stress relieved. It suits gear housings, brackets and other heavy machine castings, giving 430 MPa yield, 690 MPa tensile, 17 % elongation and 205 HB in the default condition. Machinability is about 55 % of AISI 1212, and the carbon equivalent of 0.6–0.7 means preheat and post-weld heat treatment for repair welds. Service is capped at 400 °C with no inherent corrosion resistance; SCMn1 is easier to weld and SCMn5 is stronger. SCMn3 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). SCMn3 has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 51% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi).
What is SCMn3 used for?
- Gear housings
- Heavy equipment brackets
- Structural castings
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
Limitations
- Limited formability — 15/100, worse than 87% of steel grades
SCMn3 properties
Typical room-temperature values for SCMn3-N+T; bars are the position among steel grades.
Physical3
SCMn3 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
SCMn3 has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 51% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SCMn3 is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
SCMn3 conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of SCMn3 takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 85%.
Manufacturability8
SCMn3's machinability is fair (50/100, worse than 53% of steel grades); weldability fair (45/100); formability poor (15/100).
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. SCMn3 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SCMn3
Is SCMn3 easy to machine?
Machines like a medium-carbon alloy steel (~55 % of 1212); rough-cut after normalizing, finish after final tempering, and expect abrasive skin/sand inclusions on unblasted surfaces.
Can SCMn3 be welded?
Weldable with low-hydrogen E7018/ER80S consumables but CE ≈ 0.6–0.7 — preheat 200–300 °C, control interpass, and stress-relieve or re-normalize/temper after major repair welds.
Can SCMn3 be formed, bent or molded?
Sand or shell cast with generous risering (solidification shrinkage ~5 %); avoid abrupt section changes and always heat treat to break up the coarse as-cast dendritic structure.
SCMn3 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 |
|---|---|---|
| Cdistinguishes SCMn3 from SCMn1/SCMn2/SCMn5 | 0.3 – 0.4 | 0.35 |
| Sideoxidation; upper limit per JIS G5111 | 0.3 – 0.8 | 0.5 |
| Mn | 1 – 1.6 | 1.35 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Febalance, incidental residuals (Cu, Ni, Cr, Mo) restricted by agreement | balance |
What surface finishes work on SCMn3?
No anodizing; shot-blast then phosphate + epoxy/zinc-rich paint, or zinc/hard-chrome plate wear faces — bare surfaces rust rapidly outdoors.
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 SCMn3 cost?
SCMn3 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.
SCMn3 — frequently asked
What is SCMn3 used for?
SCMn3 is typically used for gear housings, heavy equipment brackets and structural castings. In short: mid-range SCMn strength; balanced strength and cost; heat-treatable Mn casting.
What is the yield strength of SCMn3?
SCMn3 has a typical yield strength of 430 MPa (62.4 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 51% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is SCMn3 easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machines like a medium-carbon alloy steel (~55 % of 1212); rough-cut after normalizing, finish after final tempering, and expect abrasive skin/sand inclusions on unblasted surfaces.
Can SCMn3 be welded?
With care — weldability is rated fair (45/100). Weldable with low-hydrogen E7018/ER80S consumables but CE ≈ 0.6–0.7 — preheat 200–300 °C, control interpass, and stress-relieve or re-normalize/temper after major repair welds.
What surface finishes work on SCMn3?
No anodizing; shot-blast then phosphate + epoxy/zinc-rich paint, or zinc/hard-chrome plate wear faces — bare surfaces rust rapidly outdoors.
Can SCMn3 be formed, bent or molded?
Sand or shell cast with generous risering (solidification shrinkage ~5 %); avoid abrupt section changes and always heat treat to break up the coarse as-cast dendritic structure.
What is the maximum service temperature of SCMn3?
SCMn3 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SCMn3 N+T and SCMn3-A?
N+T is the default condition — default supply condition: meets the JIS G5111 SCMn3 minima (640 MPa UTS / 370 MPa YS / 13 % elongation) with balanced toughness in medium sections. A: choose when maximum machinability and dimensional stability matter more than strength, or before further heat treatment. Yield strength is 430 MPa in N+T versus 320 MPa in A.
How much does SCMn3 cost?
SCMn3 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
- JIS G 5111 — Steel castings for structural, high-strength and low-alloy service — Japanese Standards Association (2019)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- GB/T 14408 / GB/T 11352 (comparable Chinese cast-steel grades, e.g. ZG35Mn) — SAC (2014)
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.