Steel SCMn1
JIS SCMn1
SCMn1 is the lowest-alloy manganese steel casting grade in JIS G5111, supplied as-cast, annealed, normalized and tempered, or quenched and tempered.
Reference datasheet — SCMn1 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
SCMn1 tempers and conditions
SCMn1 is supplied in 4 conditions, soft to hard. N+T is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition, used for heavy rough machining or as an intermediate state before final N+T / Q+T. | 300 | 520 | 24 | 150 HB | — |
As fabricated | Non-standard shipping state for non-critical or later-heat-treated parts; JIS G5111 properties only apply after heat treatment. | 310 | 540 | 14 | 170 HB | 8 % IACS |
N+TDefault Normalized and tempered | Standard JIS G5111 delivery condition: best balance of 540 MPa-class strength, ductility and cost for general structural castings. | 380 | 580 | 21 | 175 HB | — |
Quenched and tempered | Choose when higher yield strength and section toughness are needed; limited by hardenability to moderate wall thickness. | 500 | 680 | 18 | 18 HRC | — |
What is SCMn1?
SCMn1 is the lowest-alloy manganese steel casting grade in JIS G5111, supplied as-cast, annealed, normalized and tempered, or quenched and tempered. It is specified for machine bases, brackets and railway castings that need more strength than plain carbon steel castings while remaining easy to weld and machine — 380 MPa yield, 580 MPa tensile, 21 % elongation and 175 HB, with machinability 55 and weldability 65. It has no corrosion resistance and is limited to 400 °C, so painting or galvanizing is required; step up to SCMn3 or SCMn5 when higher strength is needed. SCMn1 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). SCMn1 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 580 MPa (84.1 ksi) — weaker than 68% of steel grades. Elongation at break is 21% and the elastic modulus is 205 GPa (29.7 Msi).
What is SCMn1 used for?
- Heavy machine bases
- Structural brackets
- Railway castings
Limitations
- Limited formability — 20/100, worse than 80% of steel grades
SCMn1 properties
Typical room-temperature values for SCMn1-N+T; bars are the position among steel grades.
Physical3
SCMn1 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
SCMn1 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 580 MPa (84.1 ksi) — weaker than 68% of steel grades. Elongation at break is 21% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SCMn1 is rated for continuous service to 400°C (752 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
SCMn1 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 SCMn1 takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 80%.
Manufacturability8
SCMn1's machinability is good (55/100, better than 62% of steel grades); weldability good (65/100); formability poor (20/100).
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. SCMn1 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SCMn1
Is SCMn1 easy to machine?
Machines like normalized 1330/ZG20Mn — carbide inserts, moderate speeds; remove the hard cast skin with a heavy first cut to protect edges.
Can SCMn1 be welded?
Good weldability with low-hydrogen SMAW/FCAW or GMAW; CE ≈ 0.5–0.6, so preheat 100–200 °C on heavy sections and stress-relieve or re-normalize after major repair welds.
Can SCMn1 be formed, bent or molded?
Sand or investment cast with generous risering; Mn increases shrinkage and hot-tear sensitivity, so use adequate feeding and controlled cooling, then normalize+temper to break up the as-cast dendritic structure.
SCMn1 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 |
|---|---|---|
| CJIS G5111 | 0.2 – 0.3 | 0.25 |
| Si | 0.3 – 0.6 | 0.45 |
| Mnprimary strengthening/hardenability element | 1 – 1.6 | 1.3 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Fe | balance |
What surface finishes work on SCMn1?
No corrosion resistance of its own — shot blast, then prime/paint, zinc-rich coat, hot-dip galvanize or phosphate; hard chrome or nitriding for local wear surfaces.
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 SCMn1 cost?
SCMn1 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.
SCMn1 — frequently asked
What is SCMn1 used for?
SCMn1 is typically used for heavy machine bases, structural brackets and railway castings. In short: most weldable SCMn grade; easy-machining Mn casting; low-cost structural casting.
What is the yield strength of SCMn1?
SCMn1 has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 580 MPa (84.1 ksi) — weaker than 68% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is SCMn1 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like normalized 1330/ZG20Mn — carbide inserts, moderate speeds; remove the hard cast skin with a heavy first cut to protect edges.
Can SCMn1 be welded?
Yes — weldability is rated good (65/100). Good weldability with low-hydrogen SMAW/FCAW or GMAW; CE ≈ 0.5–0.6, so preheat 100–200 °C on heavy sections and stress-relieve or re-normalize after major repair welds.
What surface finishes work on SCMn1?
No corrosion resistance of its own — shot blast, then prime/paint, zinc-rich coat, hot-dip galvanize or phosphate; hard chrome or nitriding for local wear surfaces.
Can SCMn1 be formed, bent or molded?
Sand or investment cast with generous risering; Mn increases shrinkage and hot-tear sensitivity, so use adequate feeding and controlled cooling, then normalize+temper to break up the as-cast dendritic structure.
What is the maximum service temperature of SCMn1?
SCMn1 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 SCMn1 N+T and SCMn1-A?
N+T is the default condition — standard JIS G5111 delivery condition: best balance of 540 MPa-class strength, ductility and cost for general structural castings. A: softest condition, used for heavy rough machining or as an intermediate state before final N+T / Q+T. Yield strength is 380 MPa in N+T versus 300 MPa in A.
How much does SCMn1 cost?
SCMn1 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 G5111 — Steel castings for structural purposes (high tensile / low alloy) — JSA (2019)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (cast steels) — ASM International (1990)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America (1995)
- GB/T 14408 / ZG20Mn comparable cast structural steels — 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.