Chemical composition
Nominal: mid-range where both limits are given, the cap where only a maximum is, balance takes the remainder. Exact specified ranges below.
| Element | Name | Content % | |
|---|---|---|---|
| Main elements6 elements | |||
| Fe | Iron | Bal. | |
| Ni | Nickel | 17 – 19% | |
| Co | Cobalt | 7 – 8.5% | |
| Mo | Molybdenum | 4.6 – 5.2% | |
| Ti | Titanium | 0.3 – 0.5% | |
| Al | Aluminium | 0.05 – 0.15% | |
| Element | Name | Content % | |
|---|---|---|---|
| Minor & residual6 elements | |||
| C | Carbon | ≤ 0.03% | |
| Mn | Manganese | ≤ 0.1% | |
| Si | Silicon | ≤ 0.1% | |
| P | Phosphorus | ≤ 0.01% | |
| S | Sulphur | ≤ 0.01% | |
| Cr | Chromium | ≤ 0.5% | |
Mechanical minima by form
Guaranteed values differ by form, size and delivery condition; quotations confirm the specification, form, size and condition.
| Form | Condition | Rm MPa | Rp0.2 MPa | A ≥ % | Other requirements and notes |
|---|---|---|---|---|---|
| Several forms | |||||
| Bar, forgings, mechanical tubing and flash-welded rings (section <101.60 mm) | Supplied annealed; specimens aged at 482 ± 6 °C for 4–6 h | ≥ 1758 (255 ksi) | ≥ 1724 (250 ksi) | ≥ 6 | |
| Bar, forgings, mechanical tubing and flash-welded rings (101.60–254.00 mm) | Supplied annealed; specimens aged at 482 ± 6 °C for 4–6 h | ≥ 1689 (245 ksi) | ≥ 1655 (240 ksi) | ≥ 5 | |
| Other | |||||
| As supplied (section >12.70 mm) | Annealed and descaled | — | — | — | Also specified: Hardness ≤ 34 HRC |
| Aged condition | 482±6 °C × 4–6 h, then air cooled | — | — | — | Also specified: Hardness ≥ 48 HRC |
Where this grade is recommended
Matched in 1 service conditions; ranks and scores computed from the condition-scoring matrix.
| Service condition | Industry | Temperature | Rank | Score |
|---|---|---|---|---|
| Landing gear & forgings | Aerospace | 200 – 315 °C | 2 / 7 | 91 |
Designations & equivalents
| UNS | K92890 |
| W.Nr. (Germany) | 1.6359 |
| EN designation | X2NiCoMo18-8-5 |
| Trade name(s) | Maraging 250 / C250 / Vascomax C250 |
| AMS (SAE aerospace) | 6512 |
Cross-references are common near-equivalents for search and shortlisting; substitution across standards requires clause-by-clause verification. All grades in one cross-reference table →
Applicable standards
2 specifications. Name the standard and its edition on the order.
Guaranteed values and required tests differ between specifications — see Mechanical minima by form for the figures per form.
Frequently asked questions
What is Maraging 250 (18Ni250)?
Maraging 250 (18Ni250) — Maraging steel. 1800 MPa-class strength with toughness after ageing — aerospace structures and drive shafts
What is the maximum service temperature of 18Ni250?
Typically about 400 °C; the practical limit depends on media, stress and design life — acceptance per the governing standard.
What is the tensile strength of 18Ni250?
The specified minimum tensile strength is 1758 MPa for the main product form. Minima for other forms and sizes are listed under "Mechanical minima by form" on this page.
Which standards cover 18Ni250?
AMS 6512, MIL-S-46850D Grade 250
Where is 18Ni250 typically used?
Landing gear & forgings (Aerospace)
In which forms is 18Ni250 available?
Tube, plate, strip, bar, forgings, wire and other forms — sizes and delivery condition confirmed per order, with EN 10204 3.1 / 3.2 certification.
Same series
Download PDF datasheet
This grade’s datasheet as an A4 PDF — for filing, printing or forwarding to colleagues.
Download PDF datasheetSupply & enquiry
Tube & pipeφ1 – 219 × 0.25 – 25 mm
Plate4.76 – 80 mm
Barφ8 – 300 mm
Wire & filler metalsφ0.01 – 8 mmFor this grade we can supply, against your service conditions:
- Tube, plate, strip, bar, forgings, wire and more — with size range and lead time
- Chemistry and mechanical test report (EN 10204 3.1 / 3.2)
- Like-for-like alternatives and selection advice
- Applicable standards and inspection scope
Or email us: info@kochlin.com
Further reading: Alloy 625 Grade 1 vs Grade 2: a heat-treatment condition, not a quality level