Steel Maraging 300 · heat-treated state
Steel Maraging 300 Aged
Properties of the Aged condition, compared with the other Maraging 300 tempers.
Final service condition: ~2000 MPa strength and 50–54 HRC with minimal distortion — choose for tooling, mold inserts and high-strength structural parts.
What is Maraging 300 Aged?
Maraging 300 Aged is Maraging 300 heat treated to Aged — final service condition: ~2000 MPa strength and 50–54 HRC with minimal distortion — choose for tooling, mold inserts and high-strength structural parts. Maraging 300 Aged has a yield strength of 1,900 MPa (276 ksi) and a tensile strength of 1,950 MPa (283 ksi) — stronger than 100% of steel grades. Elongation at break is 7% and the elastic modulus is 190 GPa (27.6 Msi). Maraging 300 Aged has a density of 8 g/cm³ (0.289 lb/in³), heavier than 95% of steel grades. It melts at 1,413°C (2,575 °F). Annealed is the default condition FabDigit quotes; Aged is available on request or by drawing note.
Advantages
- High strength — 1,900 MPa (276 ksi), better than 100% of steel grades
- Polishes to a fine finish — 90/100, better than 100% of steel grades
- Good corrosion resistance — 25/100, better than 91% of steel grades
Limitations
- High embodied carbon — 6.5 kg CO₂/kg, worse than 98% of steel grades
- Limited formability — 8/100, worse than 97% of steel grades
- Limited ductility — 7%, worse than 96% of steel grades
- Poor heat conductor — 20 W/m·K (11.6 BTU/hr·ft·°F), worse than 96% of steel grades
- Low electrical conductivity — 2.9 % IACS, worse than 93% of steel grades
Maraging 300 Aged properties
Typical room-temperature values for Maraging 300 Aged — 20 properties are specific to this condition; the rest are grade-level values shared by every Maraging 300 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
Maraging 300 Aged has a density of 8 g/cm³ (0.289 lb/in³), heavier than 95% of steel grades. It melts at 1,413°C (2,575 °F).
Mechanical15
Maraging 300 Aged has a yield strength of 1,900 MPa (276 ksi) and a tensile strength of 1,950 MPa (283 ksi) — stronger than 100% of steel grades. Elongation at break is 7% and the elastic modulus is 190 GPa (27.6 Msi).
Thermal6
Maraging 300 Aged is rated for continuous service to 400°C (752 °F). It conducts heat at 20 W/m·K (11.6 BTU/hr·ft·°F), worse than 96% of steel grades. Thermal expansion is 10.1 µm/m·K (5.61 µin/in·°F).
Electrical3
Maraging 300 Aged conducts electricity at 2.9 % IACS, worse than 93% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (25/100), better than 91% of steel grades.
Sustainability4
Producing a kilogram of Maraging 300 Aged takes about 100 MJ of energy and emits 6.5 kg of CO₂ — more than 99% of steel grades. Typical recycled content is 20%.
Manufacturability8
Maraging 300 Aged's machinability is poor (25/100, worse than 93% of steel grades); weldability good (55/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other Maraging 300 tempers and conditions
Maraging 300 is also supplied in 3 other conditions. The full side-by-side table is on the Maraging 300 overview.
- As PrintedDefaultPick for as-built LPBF parts before any heat treatment: already ~35 HRC, but with residual stress and slight anisotropy.1,000 MPa yield · 35 HRC
- AnnealedDefaultStandard supply condition of wrought bar/plate: soft enough to machine, form and weld before final aging.800 MPa yield · 30 HRC
- AgedFinal service condition: ~2000 MPa strength and 50–54 HRC with minimal distortion — choose for tooling, mold inserts and high-strength structural parts.1,900 MPa yield · 52 HRC
- Stress RelievedUse on AM or welded parts to remove residual stress and prevent distortion during machining, before final aging.950 MPa yield · 33 HRC
Working with Maraging 300 Aged
Is Maraging 300 easy to machine?
Machine in the annealed/stress-relieved state with sharp carbide, rigid setups and generous coolant; aged 52 HRC material needs ceramic/CBN or grinding, and aging shrinks parts only ~0.05 %.
Can Maraging 300 be welded?
Excellent — TIG/laser/EB weld with matching filler, no preheat, low heat input and clean surfaces; re-age the weldment at 480–500 °C to restore joint strength.
Can Maraging 300 be formed, bent or molded?
Cold form, bend and deep draw only in the annealed condition (elongation ~17 %); hot work 900–1200 °C, then solution anneal — no cold forming after aging.
What surface finishes work on Maraging 300?
Takes a mirror polish (widely used for mold cavities) but is not stainless: protect with nitriding, hard chrome, electroless Ni, PVD or oil, and bake after any electroplating to avoid hydrogen embrittlement.
Maraging 300 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 |
|---|---|---|
| Cultra-low carbon essential to toughness | ≤ 0.03 | 0.01 |
| Ni | 18 – 19 | 18.5 |
| Co | 8.5 – 9.5 | 9 |
| Moforms Ni3Mo precipitates | 4.6 – 5.2 | 4.9 |
| Ti | 0.5 – 0.8 | 0.65 |
| Al | 0.05 – 0.15 | 0.1 |
| Si | ≤ 0.1 | 0.05 |
| Mn | ≤ 0.1 | 0.05 |
| P | ≤ 0.01 | — |
| S | ≤ 0.01 | — |
| Fe | balance | — |
Maraging 300 Aged — frequently asked
What is Maraging 300 Aged used for?
Maraging 300 Aged is typically used for rocket motor cases and pressure shells, additively manufactured mold inserts with conformal cooling, die and punch tooling inserts, aerospace structural fittings and actuator parts, high-torque drive shafts and couplings and motorsport and aerospace fasteners. In short: premium aerospace maraging bar.
What is the yield strength of Maraging 300 Aged?
Maraging 300 Aged has a typical yield strength of 1,900 MPa (276 ksi) and a tensile strength of 1,950 MPa (283 ksi) — stronger than 100% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is Maraging 300 Aged easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Machine in the annealed/stress-relieved state with sharp carbide, rigid setups and generous coolant; aged 52 HRC material needs ceramic/CBN or grinding, and aging shrinks parts only ~0.05 %.
Can Maraging 300 Aged be welded?
Yes — weldability is rated good (55/100). Excellent — TIG/laser/EB weld with matching filler, no preheat, low heat input and clean surfaces; re-age the weldment at 480–500 °C to restore joint strength.
What surface finishes work on Maraging 300 Aged?
Takes a mirror polish (widely used for mold cavities) but is not stainless: protect with nitriding, hard chrome, electroless Ni, PVD or oil, and bake after any electroplating to avoid hydrogen embrittlement.
Can Maraging 300 Aged be formed, bent or molded?
Cold form, bend and deep draw only in the annealed condition (elongation ~17 %); hot work 900–1200 °C, then solution anneal — no cold forming after aging.
What is the maximum service temperature of Maraging 300 Aged?
Maraging 300 Aged 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 Maraging 300 Annealed and Maraging 300 Aged?
Annealed is the default condition — standard supply condition of wrought bar/plate: soft enough to machine, form and weld before final aging. Aged: final service condition: ~2000 MPa strength and 50–54 HRC with minimal distortion — choose for tooling, mold inserts and high-strength structural parts. Yield strength is 800 MPa in Annealed versus 1,900 MPa in Aged.
Can FabDigit make parts in Maraging 300 Aged?
Yes — Maraging 300 Aged is available for CNC machining, sheet metal and 3D printing with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASM Specialty Handbook: Tool Materials / Maraging Steels — ASM International (1995)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- AMS 6514 / ASTM A538 Grade C (18Ni-300 maraging steel) — SAE / ASTM (2019)
- DIN EN ISO 4957 / Werkstoff 1.2709 — DIN (2018)
- EOS MaragingSteel MS1 material data sheet — EOS GmbH (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.