18Ni300 Alloy Powder Stainless Steel Nickel

18Ni300 (commonly marketed as Maraging 300, M300, or EN 1.2709) pre-alloyed powder is a nickel-rich maraging steel developed to deliver ultra-high strength (>1.9–2.1 GPa after aging), excellent fracture toughness, predictable dimensional stability and exceptional machinability in the annealed state — making it a top choice for demanding aerospace, tooling, and high-performance engineering parts manufactured by Laser Powder Bed Fusion (LPBF / SLM) and other powder processes. MWAlloys supplies 18Ni300 gas-atomized powder on a 100% factory-price basis with fast stock delivery and tailored lot sizes for production and prototyping.

Why choose 18Ni300?

For teams choosing a feedstock for high-stress AM or PM components, 18Ni300 maraging powder combines low carbon content with a nickel-cobalt-molybdenum-titanium chemistry engineered for precipitation (age) hardening. In its age-hardened condition it routinely reaches ~1.9–2.1 GPa ultimate tensile strength and up to ~53 HRC hardness in laboratory and production reports, while retaining good toughness and low dimensional change during thermal cycles. In short: if the design priority is maximum strength with predictable heat-treatment response, 18Ni300 is among the most proven metal powders available.

What is 18Ni300 mean?

• Names used in industry: 18Ni300, Maraging 300, M300, EN 1.2709, X3NiCoMoTi 18-9-5.

• Why “300”? Historically the “300” denotes a nominal target in the old imperial units (roughly correlating with ~300 ksi ≈ 2,070 MPa tensile strength in heavily aged condition).

• Family: Maraging steels were developed mid-20th century for aerospace and tooling where high strength plus good toughness and machinability were required. 18Ni300 is one of the most common modern grades used in additive manufacturing and tooling.

Typical chemical composition

(Numbers from leading powder datasheets and AM material datasheets — composition windows vary slightly by supplier.)

The alloy contains intentionally high Ni and significant Co and Mo with small Ti/Al additions. The extremely low C content avoids carbide precipitation; strengthening comes from nanoscale intermetallic precipitates that form during the aging (temper) step.

Powder production & recommended powder specs for AM

• Production method: gas atomization (nitrogen or argon) is the industrial standard for spherical AM powders. Good sphericity and low satellites improve flowability and layer packing.

• Common PSD (particle size distribution): typical LPBF powders are supplied in the 15–45 µm or 15–65 µm ranges depending on machine and application. Broader distributions may be used for DED processes.

• Key powder metrics: apparent density, flow rate (Hall), oxygen content (<0.02–0.1 wt.% depending on spec), D10/D50/D90. Recycled powder fraction limits and sieve sizes are important for production consistency.

Practical note (production): request supplier data sheets for: tap density, particle morphology images, oxygen and hydrogen contents, PSD histogram, and certified lot analyses before qualifying powder for flight or safety-critical applications.

Microstructure and aging mechanism

• As-built microstructure (AM): typically a martensitic matrix with retained austenite and fine cellular substructure if printed by LPBF. Post-processing heat treatment is required to develop full strength.

• Aging (precipitation hardening): the classical peak aging recipe for many 18Ni300 powders is ~480–520 °C for 4–8 (sometimes 6–10) hours, depending on part mass and desired properties. Peak hardness ≈ 50–53 HRC is commonly reported after appropriate aging. Over-aging (higher temperature or longer hold) leads to softening and possible austenite reversion.

• Solution and aging sequence: for some processes, a solution anneal (e.g., ~820–900 °C) followed by rapid cooling and then aging is used; in many LPBF workflows, direct aging from as-built yields excellent results and avoids dimensional change.

Engineering tip: Always qualify a heat-treatment cycle with representative coupons or flight hardware because part geometry, thermal mass and prior process-induced residual stress can shift the optimal aging window.

Mechanical properties — typical ranges

Important remarks: published datasets show directionality (horizontal/vertical) in as-built LPBF condition; aging reduces anisotropy. Many peer-reviewed works report peak tensile strengths ≈ 2.0 GPa after proper aging.

Corrosion, wear, and thermal stability

• Corrosion resistance: 18Ni300 is not a stainless alloy per se — chromium content is low; corrosion resistance is moderate and significantly lower than stainless grades (300 series). For corrosive environments, surface coatings or stainless cladding may be required.

• Wear resistance: wear resistance improves with aging/hardness but depends on counterface and environment; maraging steels can exhibit good tribological performance in many tooling roles.

• Thermal stability: maraging steels can be thermally stable at operating temperatures typical for tooling but prolonged exposure above aging temperature (e.g., >500–550 °C) can over-age and soften parts. For hot-service tooling, consider over-aging recipes to stabilize microstructure or choose alternative tool steels.

Manufacturability — printing, post-process, machining, welding

• Printing (LPBF): 18Ni300 prints well with standard LPBF parameter sets; process windows influence porosity, microstructure and residual stress. Energy density and scan strategy matter.

• Support & distortion: parts often require support for thin walls and overhangs; annealing/solution treatment before aggressive machining can reduce distortion.

• Machining & EDM: maraging steels machine well in soft (pre-aged) condition; often manufacturers perform aggressive machining before aging to reduce tool wear and reach final tolerances after aging (dimensional change is low).

• Welding: weldability is good in many cases, but the heat-affected zone requires aging to restore strength. For welded assemblies, match the heat-treatment plan to avoid weak zones.

Typical applications & industry examples

• Aerospace & defense: structural fittings, actuator components, rocket motor parts (where high strength/high toughness needed).

• Tooling & molds: conformal-cooled injection mold inserts, die casting tooling, sipes and high-pressure tooling—LPBF printed conformal cooling channels enabled by 18Ni300 are common.

• High-performance industry: robotics, motorsports fixtures, gages and high-load fasteners where light weight + high strength matter.

• Research & R&D: lattice structures and topology-optimized parts where high strength per mass is critical.

Quality control, traceability & standards

Relevant standards & specifications (commonly referenced):

• EN 1.2709 (European designation) — maraging 300.

• SAE / AMS series for maraging powders (e.g., AMS materials and processes listings — check specific AMS documents per application).

• ASTM A579/579M used as a related reference in some datasheets.

Supplier QA: look for certificate of analysis (CoA), full elemental analysis, particle size report, flow/density measurements, and any AMS/ISO certification relevant to your supply chain. MWAlloys provides CoAs and lot traceability for every batch shipped.

What is MWAlloys supply?

• Product: gas-atomized 18Ni300 / EN 1.2709 pre-alloyed powder, PSD options (15–45 µm; 15–65 µm), single-lot or blended lots.

• Pricing: 100% factory direct pricing — competitive bulk rates, clear MOQ and volume discounts.

• Inventory & lead times: we maintain stocked lots for prototyping and production; sample packs available; fast dispatch when you need production continuity.

• QA & service: each batch ships with CoA, PSD file, and oxygen analysis; small QC samples available on request. We also offer technical support for AM parameter window recommendations.

• Customization: packaging choices (25 kg drums, 5 kg sample), surface passivation on request, and reclaimed-powder handling policies.

Practical selection checklist

• Confirm part service temperature vs aging temp.

• Decide PSD for chosen AM process.

• Request recent CoA and oxygen content.

• Run small build coupons to validate tensile and toughness.

• Plan for solution anneal vs direct aging based on distortion tolerance.

• Establish recycled powder fraction policy.

FAQs

1. Is 18Ni300 a stainless steel?
   No. 18Ni300 is a maraging steel with low chromium and therefore does not offer the corrosion resistance of stainless grades like 316L. For corrosive service, use protective coatings or a different alloy.

2. What typical aging cycle gives peak properties?
   Many datasheets and labs report peak properties around 490 °C (≈914 °F) for 6–10 hours (part-dependent). Lower aging temperatures (∼480 °C) can favor fatigue; higher temperatures or longer holds can over-age and soften. Validate on representative parts.

3. Can I machine parts before aging?
   Yes. the alloy machines very well in the soft (pre-aged) condition; typically manufacturers finalize aggressive machining before aging to protect tooling and reach final tolerances post-age.

4. Is 18Ni300 suitable for LPBF/SLM?
   Yes. It is widely used in LPBF with tailored parameter windows; properties are build-direction sensitive in as-built state but converge after appropriate thermal processing.

5. What particle size should I choose?
   For LPBF, 15–45 µm or 15–65 µm PSDs are common. Select PSD based on machine recoater, desired layer thickness, and powder flowability.

6. How does recycled powder affect quality?
   Reclaimed powder often has higher oxygen and smaller particle fractions; follow supplier recommendations (typically capped recycling ratio and sieving) and run periodic chemical / flow checks.

7. What tensile strength can I expect after aging?
   Peak tensile strengths around ~2.0 GPa (≈2000 MPa) are routinely reported for properly aged material prepared by LPBF or conventional routes.

8. Is 18Ni300 weldable?
   Yes, it has good weldability, but welded joints should be aged to recover strength in the HAZ; evaluate residual stresses and HAZ properties for structural use.

9. What industries prefer 18Ni300?
   Aerospace, defense, injection-molding tooling (conformal cooling), motorsport components, and high-performance engineering fixtures.

10. What documentation should I get from MWAlloys?
    CoA, PSD histogram, oxygen and hydrogen analysis, lot traceability, and recommended heat-treatment notes. MWAlloys includes these with each shipment.

Authoritative references

• Osprey® 18Ni300-AM Maraging Steel — Sandvik Datasheet (Osprey 18Ni300)
• Selective Laser Melting of 18NI-300 Maraging Steel — M. Król et al., PMC (2020)