Carbon & alloy steel
Maraging Steel 18Ni(250)
Manufacturer or standards-body identification; product values do not apply to every form or condition.
Identity / state reference
What distinguishes this material
ATI distinguishes cobalt-containing C-type maraging grades from T-type grades. Grade 250 is not a complete hardness condition: solution annealing and aging produce different results.
- Designation in this reference
- C-type maraging 250
- Forms covered by the sources
- ATI technical sheet discusses bars and section-dependent treatment; match the purchased product.
- States to distinguish or confirm
- Solution-annealed delivery and subsequently aged condition must be separate.
- Temperature and exposure
- No universal service-temperature limit or room-temperature property set is assigned. Use the cited product document and the purchase certificate.
Property evidence for a stated condition
No condition-specific numerical table is reproduced here
The linked sources establish the identity and the stated product/state scope. Obtain the row for your actual form, section, treatment and test conditions before adopting strength, hardness or a thermal limit.
Resolve these conditions next
- What product standard, edition and complete grade are on the material certificate?
- What product form, section size and delivery/heat-treatment condition will be machined?
For machining, take the exact grade, supplied condition and measured hardness where applicable into the tool maker’s application data. A generic material-family speed is not a substitute for an operation and tool-specific recommendation.
Sources and what they establish
Reviewed 23 October 2026. A source’s publication date and the review date are different. The scope below identifies the fields checked.
ATI C-type maraging steel technical datasheet
C-200/C-250/C-300/C-350; distinguishes solution-annealed delivery from aging and C-type from T-type.
ATI C-type maraging steel technical datasheet ↗Source identity, a named product example and a supplied-batch certificate are different evidence. Cross-standard similarity does not approve substitution.
Corrections from the previous article
- Correct the old attribution of 30–35 HRC to the aged state: the ATI sheet discusses that soft hardness in the solution-annealed state; do not pair it with aged tensile strength.
- Withdraw the legacy generic hardness (30–35 HRC (aged)) and tensile-strength (1,760 MPa (255 ksi) aged) pair: the old page does not establish a matching product, heat treatment, section and test source.
- Remove the unsupported cutting-speed table and machinability percentage; select tooling only after the actual material condition is known.
Other references in Carbon & alloy steel
Related references, not equivalent substitutes.