Steel 18Ni350
EN 18Ni350
18Ni350 (K92890, 1.6359) is an 18 % nickel maraging steel powder that hardens by intermetallic precipitation during a low-temperature aging step rather than by quenching.
Reference datasheet — 18Ni350 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the SA+A condition
18Ni350 tempers and conditions
18Ni350 is supplied in 7 conditions, soft to hard. SA+A is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed 815 °C/1 h, air cooled | Machining and forming condition — soft, tough and dimensionally stable before the low-distortion aging step. | 860 | 1,100 | 15 | 32 HRC | 19 W/m·K |
As built (as printed) | Printed and stress-relieved but not aged — machine/EDM features in this softer state before hardening. | 1,000 | 1,180 | 9 | 37 HRC | 2.4 % IACS |
As-built L-PBF + direct age 490 °C/6 h | Fastest route to hardened AM tooling inserts — near-full strength with minimal distortion, but lower ductility than wrought. | 2,000 | 2,100 | 3 | 56 HRC | 2.7 % IACS |
Solution annealed + under-aged 480 °C/3 h | Choose when a little strength can be traded for higher fracture toughness and impact energy in thick or notch-sensitive sections. | 2,100 | 2,200 | 9 | 54 HRC | 2.6 % IACS |
Hot isostatic pressed, solution annealed and aged | Specify for fatigue-critical or aerospace AM parts where residual porosity must be closed and properties matched to wrought. | 2,250 | 2,350 | 6 | 57 HRC | 2.7 % IACS |
SA+ADefault Solution annealed + aged 490 °C/6 h | Standard delivered/ finished condition for tooling and high-stress parts — maximum strength and hardness at ~2400 MPa. | 2,300 | 2,400 | 7 | 57 HRC | 15 W/m·K |
Aged then gas/plasma nitrided surface | Use for punches, dies and wear surfaces — nitriding at the aging temperature range adds a ~1100 HV case without softening the core. | 2,300 | 2,400 | 5 | 57 HRC | 2.7 % IACS |
Supply forms, finishes and certifications
Ways 18Ni350 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
PWD | Gas-atomised powder, as supplied | Supply form |
What is 18Ni350?
18Ni350 (K92890, 1.6359) is an 18 % nickel maraging steel powder that hardens by intermetallic precipitation during a low-temperature aging step rather than by quenching. After solution treatment and aging it reaches 2300 MPa yield and 2400 MPa tensile strength with 7 % elongation and 57 HRC, so it is chosen for L-PBF mould inserts and tooling that must be machined soft and hardened with minimal distortion. Thermal conductivity is 15 W/m·K and service is limited to about 400 °C. Machinability in the aged state is very low (score 18) and the alloy is not corrosion resistant, so surface treatment is required; 18Ni300 is the lower-strength, more forgiving alternative. 18Ni350 has a density of 8.08 g/cm³ (0.292 lb/in³), heavier than 96% of steel grades. It melts at 1,413°C (2,575 °F). 18Ni350 has a yield strength of 2,300 MPa (334 ksi) and a tensile strength of 2,400 MPa (348 ksi) — stronger than 100% of steel grades. Elongation at break is 7% and the elastic modulus is 190 GPa (27.6 Msi).
What is 18Ni350 used for?
- mold inserts
- aerospace tooling
- high-strength brackets
Advantages
- High strength — 2,300 MPa (334 ksi), better than 100% of steel grades
- Polishes to a fine finish — 85/100, better than 99% of steel grades
- Good corrosion resistance — 25/100, better than 92% of steel grades
Limitations
- Poor heat conductor — 15 W/m·K (8.67 BTU/hr·ft·°F), worse than 98% of steel grades
- Difficult to machine — 18/100, worse than 97% of steel grades
- Limited ductility — 7%, worse than 96% of steel grades
- Low electrical conductivity — 2.7 % IACS, worse than 96% of steel grades
- High embodied carbon — 5.2 kg CO₂/kg, worse than 96% of steel grades
18Ni350 properties
Typical room-temperature values for 18Ni350-SA+A; bars are the position among steel grades.
Physical3
18Ni350 has a density of 8.08 g/cm³ (0.292 lb/in³), heavier than 96% of steel grades. It melts at 1,413°C (2,575 °F).
Mechanical15
18Ni350 has a yield strength of 2,300 MPa (334 ksi) and a tensile strength of 2,400 MPa (348 ksi) — stronger than 100% of steel grades. Elongation at break is 7% and the elastic modulus is 190 GPa (27.6 Msi).
Thermal6
18Ni350 is rated for continuous service to 400°C (752 °F). It conducts heat at 15 W/m·K (8.67 BTU/hr·ft·°F), worse than 98% of steel grades. Thermal expansion is 10.3 µm/m·K (5.72 µin/in·°F).
Electrical3
18Ni350 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 18Ni350 takes about 70 MJ of energy and emits 5.2 kg of CO₂ — more than 97% of steel grades. Typical recycled content is 20%.
Manufacturability7
18Ni350's machinability is poor (18/100, worse than 97% of steel grades); weldability good (55/100); formability poor (20/100).
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. 18Ni350 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 18Ni350
Is 18Ni350 easy to machine?
Rough machine in the solution-annealed state (~32 HRC) with sharp carbide tooling and rigid setups; after aging to 57 HRC use grinding, EDM or CBN only.
Can 18Ni350 be welded?
Excellent TIG/laser/EB weldability with matching filler and no preheat — weld annealed, then age the whole part; keep heat input low and interpass cool to limit reverted austenite.
Can 18Ni350 be formed, bent or molded?
Cold form or bend only when annealed; aging causes just ~0.05 % shrinkage so parts can be finished near net size before hardening, and L-PBF prints readily with low cracking risk.
18Ni350 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 | 18 – 19 | 18.5 |
| Co | 11 – 12.5 | 12 |
| Mo | 4.6 – 5.2 | 4.9 |
| Tiprincipal age-hardening element vs 18Ni300 | 1.3 – 1.6 | 1.45 |
| Al | 0.05 – 0.15 | 0.1 |
| C | ≤ 0.03 | 0.01 |
| Si | ≤ 0.1 | 0.05 |
| Mn | ≤ 0.1 | 0.05 |
| P | ≤ 0.01 | 0.01 |
| S | ≤ 0.01 | 0.01 |
| Bgrain refining addition, optional | ≤ 0 | 0 |
| Zroptional | ≤ 0.02 | 0.01 |
| Fe | balance |
What surface finishes work on 18Ni350?
Polishes to mirror for mould surfaces; not corrosion resistant, so nitride, hard chrome/electroless nickel plate, black oxide or oil for storage and service.
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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 18Ni350 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.6359
- Similar grades
- K92890
How much does 18Ni350 cost?
18Ni350 is a high-cost steel ($$$$), pricier than about 78% 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.
18Ni350 — frequently asked
What is 18Ni350 used for?
18Ni350 is typically used for mold inserts, aerospace tooling and high-strength brackets. In short: highest-strength maraging powder; machine soft, age to 57 HRC; near-zero aging distortion.
What is the yield strength of 18Ni350?
18Ni350 has a typical yield strength of 2,300 MPa (334 ksi) and a tensile strength of 2,400 MPa (348 ksi) — stronger than 100% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 18Ni350 easy to machine?
Not especially — machinability is rated poor (18/100, worse than 97% of steel grades). Rough machine in the solution-annealed state (~32 HRC) with sharp carbide tooling and rigid setups; after aging to 57 HRC use grinding, EDM or CBN only.
Can 18Ni350 be welded?
Yes — weldability is rated good (55/100). Excellent TIG/laser/EB weldability with matching filler and no preheat — weld annealed, then age the whole part; keep heat input low and interpass cool to limit reverted austenite.
What surface finishes work on 18Ni350?
Polishes to mirror for mould surfaces; not corrosion resistant, so nitride, hard chrome/electroless nickel plate, black oxide or oil for storage and service.
Can 18Ni350 be formed, bent or molded?
Cold form or bend only when annealed; aging causes just ~0.05 % shrinkage so parts can be finished near net size before hardening, and L-PBF prints readily with low cracking risk.
What is the maximum service temperature of 18Ni350?
18Ni350 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 18Ni350 SA+A and 18Ni350-SA?
SA+A is the default condition — standard delivered/ finished condition for tooling and high-stress parts — maximum strength and hardness at ~2400 MPa. SA: machining and forming condition — soft, tough and dimensionally stable before the low-distortion aging step. Yield strength is 2,300 MPa in SA+A versus 860 MPa in SA.
How much does 18Ni350 cost?
18Ni350 is a high-cost steel ($$$$), pricier than about 78% 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.
Sources
- AMS 6515 — Steel, Maraging Bars, Forgings and Tubing 18Ni(350) — SAE International (2019)
- ASM Specialty Handbook: Maraging Steels (in Tool Materials / Carbon and Alloy Steels) — ASM International (1996)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Maraging steel 18Ni350 / MS1-350 powder data sheets — Various AM powder producers (Sandvik Osprey, Höganäs, CNPC/ ) (2023)
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.