Maraging Steel MS1 (18Ni-300)

metal

maraging steel (ultra-high-strength, precipitation-hardened)

18Ni-300DIN 1.2709UNS K93120EOS MS1Vascomax 300AMS 6514 (wrought ref.)

Maraging Steel MS1 (18Ni-300) 3D printed component

Density

8.05 g/cm³

YS (LPBF as-built (XY) — soft martensite)

940–1150 MPa

UTS (LPBF as-built (XY) — soft martensite)

1030–1270 MPa

Elongation (LPBF as-built (XY) — soft martensite)

7.0–15.0 %

Elastic modulus

170–190 GPa

Thermal conductivity

16.0–18.5 W/m·K

Composition — DIN 1.2709 / UNS K93120 / AMS 6514

Element	Min %	Max %	Notes
Ni	17.00	19.000	High Ni for martensite transformation without carbon; key for intermetallic precipitation
Co	8.50	9.500	Lowers martensite finish temperature; promotes Mo precipitation on ageing
Mo	4.50	5.200	Primary age-hardening precipitate Ni₃Mo; solid solution strengthener
Ti	0.50	0.800	Forms Ni₃Ti precipitates; critical for achieving peak hardness on ageing
Al	0.05	0.150	Deoxidiser; promotes ordered Ni₃(Al,Ti) phase

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Mechanical & thermal properties — 3 conditions

Property	LPBF as-built (XY) — soft martensite	LPBF aged 480°C/6h (XY) — peak hardness	LPBF aged 480°C/6h (Z)
Elastic modulus	170–190 GPa	—	—
Yield strength (0.2%)	940–1150 MPa	1760–1970 MPa	1640–1860 MPa
Ultimate tensile strength	1030–1270 MPa	1870–2100 MPa	1750–1980 MPa
Elongation at break	7.0–15.0 %	2.0–7.0 %	1.5–5.0 %
Hardness (HV)	340–410 HV10	530–610 HV10	520–600 HV10
Fatigue strength	—	650–850 MPa	—
Density	8.05 g/cm³	—	—
Thermal conductivity	16.0–18.5 W/m·K	—	—
CTE	10.2–11.2 µm/m·K	—	—

Values shown as min–max where a spread is reported, otherwise as typical ± unit. Ranges reflect inter-source variation, not single-sample scatter. All values are for AM-processed specimens unless noted.

Engineering considerations

Ageing protocol: 480–490°C for 4–8h (vacuum preferred, inert atmosphere acceptable). Peak hardness at ~5–6h at 480°C. Over-ageing at 500°C+ causes precipitate coarsening and hardness loss. Measure hardness after each ageing batch.
Tooling design for conformal cooling: minimum channel diameter 1.5 mm (printable), typical 3–5 mm for cooling channels. Channel wall thickness minimum 1.5 mm to handle injection pressure (up to 200 MPa). Use computational mould flow analysis to optimise channel layout.
Dimensional change on ageing: linear shrinkage 0.05–0.08% — account for this in pre-age dimensions when tolerances are tight (±0.01 mm).
Surface finish for mould inserts: as-built Ra 10–15 µm. Post-machining to Ra <0.4 µm (polished), then EDM or hand polishing to Ra <0.1 µm (mirror) for Class A cosmetic surfaces.
Fatigue in tooling: typical injection mould tool sees 10–50 million cycles over lifetime. Design for 10⁷ cycle endurance at nominal stress — use FEA to verify gate and runner areas where stress concentrations occur.
Heat treatment sequence for tooling inserts: LPBF → stress-relieve (300°C/1h, reduces distortion risk) → machine cavity to near-final size → age (480°C/5h) → finish grind/EDM/polish.
Welding/repair: maraging steel responds well to laser micro-welding using matching 18Ni filler wire. Post-weld local ageing (480°C/3h at weld zone) restores hardness without full re-ageing the tool.
Print orientation for tooling: print the mould cavity face in XY (highest mechanical properties at the contact surface). Gate areas should be in XY if possible — highest cyclic stress location.

Advantages

Highest strength of any standard LPBF metal — YS 1870 MPa, UTS 1990 MPa (aged) surpasses all other AM metals
Near-zero dimensional change on ageing (<0.1% linear) — machine in soft state, age to final hardness
Achieves injection mould tool hardness (52–54 HRC) without quench-and-temper distortion risk
Conformal cooling channels: LPBF enables complex internal channels impossible in machined H13/P20 tooling — 20–40% cycle time reduction in injection moulding
Good machinability in as-built state (37–40 HRC) — conventional machining with carbide tooling
Good EDM machinability — electrode wear is low; important for mould cavity finishing
Isotropic ageing response — hardness is uniform regardless of build orientation
Weldable (laser and TIG) with maraging 18Ni filler — mould repair without re-aging in some cases

Limitations

Very low ductility after ageing (2–7%) — not suitable for impact loading or crash-absorbing structures
Mandatory ageing required for structural use — as-built properties (37 HRC) are insufficient for tooling
High cost: raw powder 4–6× more expensive than tool steel P20 per kg. Cost-justified primarily for complex conformal cooling tooling
Co content raises bio-release concerns for implantable devices — not used for medical implants
Over-ageing above 510°C causes Ni₃Mo dissolution and hardness reduction — temperature control within ±5°C is critical
Susceptible to hydrogen embrittlement in certain plating processes — avoid acid pickling without pre-bake
Limited corrosion resistance compared to stainless — may require surface coating (TiN, CrN PVD) for corrosive media exposure
Print parameter sensitivity: maraging steel has narrow VED window for optimal density; deviations cause LOF porosity that reduces fatigue life

Typical applications

Injection mould inserts with conformal cooling channelsDie-casting inserts and die-casting toolingHigh-pressure forming tools and press hardening diesAerospace structural brackets and fasteners (ultra-high-strength)Motorsport suspension components and uprightsRocket engine thrust chambers and nozzle hardwareHigh-performance cutting tool bodies and insertsPrecision jigs and fixtures requiring high dimensional stabilityUnderwater and ballistic components requiring extreme strength

Standards & certifications

ASTM-E8established

Tensile test method for acceptance testing of AM maraging steel

aerospacetoolingindustrial

ASTM-E466established

Force-controlled fatigue testing — critical for tooling fatigue qualification

aerospacetooling

ISO-52904established

Process quality assurance for safety-critical PBF parts

aerospacedefence

Maraging Steel MS1 (18Ni-300)

Composition — DIN 1.2709 / UNS K93120 / AMS 6514

Mechanical & thermal properties — 3 conditions

Engineering considerations

Advantages

Limitations

Typical applications

Industries

Standards & certifications

Compatible AM processes (1)

Other metal materials

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