Steel Maraging 250
UNS K92900 · AISI/SAE 18Ni250 · ASTM A538 Grade B · EN 18Ni-250, 1.6359
Maraging 250 (18Ni250, 1.6359, ASTM A538 Grade B, UNS K92900) is an ultra-low-carbon Fe-18Ni-Co-Mo-Ti steel that gains strength from intermetallic precipitation during a 480 °C age rather than from carbon quenching.
Values for the Annealed condition
Maraging 250 tempers and conditions
Maraging 250 is supplied in 6 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot isostatic pressed | Use when internal porosity and fatigue scatter in printed or cast parts must be closed out; leaves the alloy soft and ready for aging. | 800 | 1,000 | 16 | 30 HRC | 2.7 % IACS |
AnnealedDefault solution annealed ~815 °C, air cooled (soft martensite) | Standard as-supplied condition for bar, plate and sheet: soft and tough for machining, forming and welding before aging. | 810 | 1,010 | 18 | 30 HRC | 26 W/m·K |
printed part stress-relieved / re-solutioned (~815–900 °C) | Choose for printed or welded parts that must be machined flat and distortion-free before the final maraging age. | 860 | 1,050 | 14 | 32 HRC | 2.7 % IACS |
laser powder-bed fusion, no post heat treatment | Green additive condition: usable strength but residual stress and anisotropy; normally aged or solution-treated + aged before service. | 950 | 1,130 | 12 | 34 HRC | 2.5 % IACS |
cold drawn annealed bar/wire (unaged) | Use for small-diameter bar and wire where drawn tolerance and extra unaged strength are wanted before the age cycle. | 1,000 | 1,150 | 10 | 34 HRC | 2.7 % IACS |
480 °C / 3–6 h maraging after solution anneal | Pick for the final service condition: ~1750–1800 MPa with high toughness and almost no distortion or scale from the age cycle. | 1,730 | 1,790 | 10 | 50 HRC | 20 W/m·K |
What is Maraging 250?
Maraging 250 (18Ni250, 1.6359, ASTM A538 Grade B, UNS K92900) is an ultra-low-carbon Fe-18Ni-Co-Mo-Ti steel that gains strength from intermetallic precipitation during a 480 °C age rather than from carbon quenching. It is machined, formed and welded in the soft condition and then aged with only about 0.05 % predictable shrinkage, reaching roughly 1700 MPa yield with good fracture toughness; forms include bar, plate and laser powder-bed printed parts. Limits are alloy cost, no chromium for corrosion resistance, a 400 °C service ceiling and a machinability rating of 45. Use 4340 where 1700 MPa is not required. Maraging 250 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). Maraging 250 has a yield strength of 810 MPa (117 ksi) and a tensile strength of 1,010 MPa (146 ksi) — stronger than 87% of steel grades. Elongation at break is 18% and the elastic modulus is 181 GPa (26.3 Msi).
What is Maraging 250 used for?
- Rocket motor cases
- Centrifuge rotors
- Aerospace structural fittings
- Die-casting and injection mould inserts
- High-load shafts and couplings
- Load cells and flexures
- Additively manufactured tooling
Advantages
- Polishes to a fine finish — 85/100, better than 99% of steel grades
- Good corrosion resistance — 25/100, better than 92% of steel grades
- High strength — 810 MPa (117 ksi), better than 87% of steel grades
- Readily welded — 80/100, better than 79% of steel grades
Limitations
- High embodied carbon — 7 kg CO₂/kg, worse than 99% of steel grades
- Low stiffness — 181 GPa (26.3 Msi), worse than 96% of steel grades
- Low electrical conductivity — 2.7 % IACS, worse than 96% of steel grades
- Poor heat conductor — 25.5 W/m·K (14.7 BTU/hr·ft·°F), worse than 88% of steel grades
Maraging 250 properties
Typical room-temperature values for Maraging 250-Annealed; bars are the position among steel grades.
Physical3
Maraging 250 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 250 has a yield strength of 810 MPa (117 ksi) and a tensile strength of 1,010 MPa (146 ksi) — stronger than 87% of steel grades. Elongation at break is 18% and the elastic modulus is 181 GPa (26.3 Msi).
Thermal6
Maraging 250 is rated for continuous service to 400°C (752 °F). It conducts heat at 25.5 W/m·K (14.7 BTU/hr·ft·°F), worse than 88% of steel grades. Thermal expansion is 10.1 µm/m·K (5.61 µin/in·°F).
Electrical3
Maraging 250 conducts electricity at 2.7 % IACS, worse than 96% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (25/100), better than 92% of steel grades.
Sustainability4
Producing a kilogram of Maraging 250 takes about 90 MJ of energy and emits 7 kg of CO₂ — more than 98% of steel grades. Typical recycled content is 30%.
Manufacturability8
Maraging 250's machinability is fair (45/100, worse than 65% of steel grades); weldability very good (80/100); formability good (55/100).
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. Maraging 250 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Maraging 250
Is Maraging 250 easy to machine?
Machine in the annealed condition with sharp carbide tooling, rigid setups and generous coolant (about 45 % of 1212); finish-machine before the 480 °C age, which causes only ~0.05 % predictable shrinkage.
Can Maraging 250 be welded?
Excellent — GTAW/EBW with matching filler, no preheat, low interpass heat and no hydrogen concern; age the weldment after welding to restore joint strength.
Can Maraging 250 be formed, bent or molded?
Cold-form, spin or deep-draw only in the annealed state; hot work 900–1200 °C and always re-solution anneal at ~815 °C before aging.
Manufacturability
The process limits FabDigit's quote engine applies to Maraging 250. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Fair45 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Fair55 / 100 |
|---|---|
| Weldability | Better80 / 100 |
3D printing
| Technologies | DMLS |
|---|---|
| Layer height | 20 – 60 µmdefault 30 µm |
| Minimum wall / feature | 0.5 / 0.3 mm |
| Build envelope | 250 × 250 × 325 mm |
| Supports | Yes |
| Anisotropy | Mild |
| Mandatory post-processing | heat treatment |
Maraging 250 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 |
|---|---|---|
| Ni | 17 – 19 | 18 |
| Co | 7 – 8.5 | 7.8 |
| Mo | 4.6 – 5.2 | 4.9 |
| Tiprimary age-hardening addition (Ni3Ti) | 0.3 – 0.5 | 0.4 |
| Al | 0.05 – 0.15 | 0.1 |
| Ckept low for toughness | ≤ 0.03 | 0.02 |
| Si | ≤ 0.1 | 0.05 |
| Mn | ≤ 0.1 | 0.05 |
| S | ≤ 0.01 | 0 |
| P | ≤ 0.01 | 0.01 |
| Bgrain-refining addition, optional | ≤ 0 | 0 |
| Zroptional | ≤ 0.02 | 0.01 |
| Caoptional | ≤ 0.05 | 0.02 |
| Fe | balance |
What surface finishes work on Maraging 250?
Cannot be anodized; protect the Cr-free surface by nickel or cadmium plating, nitriding (which the age cycle can share), black oxide or paint — it polishes to a mirror finish for die and mold work.
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
CVD Coating
Black / Phosphate
Thermal Spray
Metal Finish
Equivalent designations
Standards and trade names that resolve to Steel Maraging 250 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- K92900
- AISI / SAE
- 18Ni250
- ASTM
- A538 Grade B
- EN / DIN / Werkstoff-Nr.
- 18Ni-2501.6359
How much does Maraging 250 cost?
Maraging 250 is a standard-cost steel ($$), cheaper than about 62% 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.
Maraging 250 — frequently asked
What is Maraging 250 used for?
Maraging 250 is typically used for rocket motor cases, centrifuge rotors, aerospace structural fittings, die-casting and injection mould inserts, high-load shafts and couplings and load cells and flexures. In short: premium aerospace maraging bar.
What is the yield strength of Maraging 250?
Maraging 250 has a typical yield strength of 810 MPa (117 ksi) and a tensile strength of 1,010 MPa (146 ksi) — stronger than 87% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is Maraging 250 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in the annealed condition with sharp carbide tooling, rigid setups and generous coolant (about 45 % of 1212); finish-machine before the 480 °C age, which causes only ~0.05 % predictable shrinkage.
Can Maraging 250 be welded?
Yes — weldability is rated very good (80/100). Excellent — GTAW/EBW with matching filler, no preheat, low interpass heat and no hydrogen concern; age the weldment after welding to restore joint strength.
What surface finishes work on Maraging 250?
Cannot be anodized; protect the Cr-free surface by nickel or cadmium plating, nitriding (which the age cycle can share), black oxide or paint — it polishes to a mirror finish for die and mold work.
Can Maraging 250 be formed, bent or molded?
Cold-form, spin or deep-draw only in the annealed state; hot work 900–1200 °C and always re-solution anneal at ~815 °C before aging.
What is the maximum service temperature of Maraging 250?
Maraging 250 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 250 Annealed and Maraging 250 Aged?
Annealed is the default condition — standard as-supplied condition for bar, plate and sheet: soft and tough for machining, forming and welding before aging. Aged: pick for the final service condition: ~1750–1800 MPa with high toughness and almost no distortion or scale from the age cycle. Yield strength is 810 MPa in Annealed versus 1,730 MPa in Aged.
How much does Maraging 250 cost?
Maraging 250 is a standard-cost steel ($$), cheaper than about 62% 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 Maraging 250?
Yes — Maraging 250 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
- AMS 6512 — Steel, Maraging, Bars, Forgings, 18Ni-8Co-5Mo (250 grade) — SAE International (2018)
- MIL-S-46850 — Steel, Bar, Plate, Sheet, Maraging, 18 Ni — US DoD (1991)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys (Maraging Steels) — ASM International (1990)
- Vascomax C250 / Maraging C250 alloy datasheet — Carpenter Technology (2023)
- MMPDS-2023 typical property tables, 18Ni maraging steels — Battelle/FAA (2023)
- Maraging steel LPBF process and property data — EOS / SLM Solutions (2022)
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.