1.6354 Forgings X2NiCoMo18-9-5 · Maraging 300 · 18Ni(300) · Vascomax C300
Open-die forged rings, flanges, shafts, discs, sleeves, bushings, tube sheets and blocks in 1.6354 maraging steel, made to drawing at our works in Jiangyin, Jiangsu.
1.6354 is the European material number (Werkstoff-Nr.) for X2NiCoMo18-9-5, an 18 % nickel cobalt-molybdenum maraging steel. The same grade is sold as Maraging 300, 18Ni(300), C300 and Vascomax C300, and is covered by UNS K93120 and AMS 6514. It is an iron-based martensitic steel with almost no carbon. It is machined at 30–35 HRC and then age-hardened at 480 °C to a yield strength above 1 862 MPa (270 ksi), with very little distortion.
Jiangyin Jiangnan Metal Co., Ltd. forges 1.6354 to customer drawings as seamless rolled rings, flanges, shafts, discs, sleeves and blocks. Forgings are supplied solution-annealed, ultrasonically tested to EN 10228-3 or ASTM A388, with EN 10204 3.1 or 3.2 certification. Send a drawing to sales@steelforgepieces.com for a quotation.
30–35HRC
Rp0.2 ≈ 760–900 MPa
Machines, drills and welds freely
50–54HRC
Rp0.2 ≥ 1 862 MPa (270 ksi)
≈ 0.1 % uniform contraction only
Values are typical for fully aged 1.6354 / Maraging 300 to AMS 6514. Certified values for your heat are stated on the mill test certificate issued with each order.
What 1.6354 is
1.6354 is a steel containing 18 % nickel, not a nickel-base alloy of the Inconel or Hastelloy type. It appears in this section because of its nickel content. Its strength comes from intermetallic precipitates of nickel with molybdenum and titanium rather than from carbon.
Conventional high-strength steels are hardened by quenching carbon into a distorted martensite lattice. Parts move during the quench, and cracking and straightening are common. 1.6354 contains a maximum of 0.03 % carbon. On cooling from the solution-annealing temperature it forms a soft, tough martensite at about 30–35 HRC and stays there, so it can be turned, milled, bored, drilled and welded much like a mild alloy steel.
Strength is developed later, by a single ageing treatment at 480 °C that precipitates Ni3Mo and Ni3Ti inside the existing martensite. There is no phase transformation and no quench. The part contracts by about 0.1 % uniformly. Because that figure is small and repeatable, many customers finish-machine before ageing and avoid post-hardening grinding.
There are two consequences for a forging supplier. Large open-die shapes can be produced with sound cores and no quench cracking, and forgings are delivered in the machinable condition so the buyer sets the final properties.
1.6354 key data
- Material number
- 1.6354
- EN designation
- X2NiCoMo18-9-5
- Common name
- Maraging 300
- UNS
- K93120
- Density
- 8.0 g/cm³
- Aged hardness
- 50–54 HRC
- Aged Rm
- ≈ 2 000 MPa
- Magnetic
- Ferromagnetic
1.6354 forgings we produce
Every item below is made to drawing or size list. We hold no standard catalogue of finished 1.6354 parts, as the grade is normally bought for specific, highly stressed components.
Seamless rolled rings & forged rings
Ring-rolled or mandrel-forged 1.6354 rings with continuous circumferential grain flow, the preferred form for hoop-loaded parts.
Discs, disks and blanks
Upset and drawn 1.6354 discs for rotors, couplings, closure plates and gear blanks, with the fibre structure oriented radially.
Shafts, spindles & eccentric shafts
Stepped and straight 1.6354 forged shafts for transmission, actuator and rotor duties with high torque density.
Sleeves, bushings & tubes
Bored and drawn 1.6354 hollows and forged tubes for pressure, wear and guide applications.
Flanges, tube sheets & plates
1.6354 forged flanges, tube sheets and rectangular blocks for pressure envelopes, heat exchangers and die bases.
Forged round bar & billet
Forged and peeled 1.6354 round bar and square billet, supplied solution-annealed for onward machining.
Size range. Practical limits for 1.6354 depend on ingot supply as much as on press capacity, so we do not publish a fixed size table. Send your drawing or approximate dimensions to sales@steelforgepieces.com and we will confirm in writing whether the piece is within range, together with the input ingot size and machining allowances.
Also available: forged rings in other grades, and the related maraging grades listed in § 10.
Chemical composition of 1.6354
The composition below is the specified range for 1.6354 / Maraging 300 supplied by Jiangyin Jiangnan Metal. Carbon, sulphur and phosphorus are held low. Cleanliness is what allows the grade to stay tough at 2 000 MPa.
| Element | Symbol | Weight % | Role in the alloy |
|---|---|---|---|
| Carbon | C | 0.03 max | Held low; carbides embrittle rather than strengthen |
| Silicon | Si | 0.10 max | Residual from melting |
| Manganese | Mn | 0.10 max | Residual from melting |
| Sulphur | S | 0.010 max | Controlled for transverse toughness |
| Phosphorus | P | 0.010 max | Controlled for transverse toughness |
| Nickel | Ni | 18.0 – 19.0 | Forms the soft martensite matrix; host for precipitates |
| Cobalt | Co | 8.0 – 9.5 | Lowers Mo solubility, driving Ni3Mo precipitation |
| Molybdenum | Mo | 4.6 – 5.2 | Principal hardening element |
| Titanium | Ti | 0.55 – 0.80 | Forms Ni3Ti; higher than in Maraging 250 |
| Aluminium | Al | 0.05 – 0.15 | Deoxidation and supplementary hardening |
| Iron | Fe | Balance | Base metal |
Ladle and product analysis are reported on the EN 10204 3.1 certificate supplied with each forging. Where a specification imposes tighter residual limits, state them on the enquiry and we will melt to them.
Mechanical and physical properties
Mechanical properties, annealed and aged
Properties differ greatly between the two heat-treatment conditions. Forgings leave our works solution-annealed unless ageing is ordered.
| Property | Solution annealed 815–825 °C, air cool | Aged 480 °C, 3–6 h, air cool |
|---|---|---|
| Tensile strength Rm | 1 000 – 1 170 MPa | 1 930 – 2 050 MPa (280–297 ksi) |
| Yield strength Rp0.2 | 760 – 900 MPa | ≥ 1 862 MPa (270 ksi) |
| Elongation A5 | 15 – 19 % | 6 – 10 % |
| Reduction of area | 60 – 75 % | 35 – 50 % |
| Hardness | 30 – 35 HRC | 50 – 54 HRC |
| Fracture toughness KIC | — | ≈ 70 – 90 MPa·m½ |
| Useful service temperature | — | up to ≈ 400 – 450 °C |
| Low-temperature behaviour | — | retains good notch toughness to −50 °C |
Indicative values compiled from AMS 6514 minima and published producer data. They are not a guarantee for a specific forging: section size, forging reduction and test-piece location all affect the result. We certify tested values per heat and, where required, per forging.
Physical properties
| Property | Value (metric) | Value (imperial) |
|---|---|---|
| Density | 8.0 g/cm³ | 0.289 lb/in³ |
| Modulus of elasticity (aged) | ≈ 190 GPa | ≈ 27.6 × 10⁶ psi |
| Mean CTE, 20–100 °C | ≈ 10.1 × 10⁻⁶ /K | ≈ 5.6 × 10⁻⁶ /°F |
| Thermal conductivity, 20 °C | ≈ 20 W/m·K | ≈ 11.6 BTU/h·ft·°F |
| Specific heat | ≈ 450 J/kg·K | ≈ 0.107 BTU/lb·°F |
| Electrical resistivity | ≈ 0.60 µΩ·m | ≈ 360 Ω·circ mil/ft |
| Melting range | ≈ 1 413 – 1 440 °C | ≈ 2 575 – 2 625 °F |
| Magnetic response | Ferromagnetic in all conditions | |
1.6354 equivalent grades and cross-reference
The same 18Ni(300) maraging steel appears under several designations. A German drawing may call it 1.6354, a US aerospace print AMS 6514, and a mill certificate Vascomax C300.
| System / standard | Designation |
|---|---|
| Werkstoff-Nr. (DIN / EN) | 1.6354; closely related 1.6358 |
| EN / DIN name | X2NiCoMo18-9-5; Ti-bearing variant X2NiCoMoTi18-9-5 |
| UNS | K93120 |
| SAE / AMS — bar, billet, forgings | AMS 6514 |
| SAE / AMS — sheet, strip, plate | AMS 6521 |
| ASTM | ASTM A579 (high-strength steel forgings) |
| US military | MIL-S-46850 Type 300; MIL-S-13881 |
| Common / trade names | Maraging 300 · 18Ni(300) · M300 · C300 · Vascomax C300 · Vdimor 300 |
| China (approximate) | ≈ 00Ni18Co9Mo5TiAl (18Ni-300 type) |
| Adjacent grades | 1.6359 / X2NiCoMo18-8-5 / UNS K92890 = Maraging 250 (lower strength, higher toughness) |
Before substituting. Cross-references are a starting point rather than a guarantee of equivalence. National standards differ in residual limits, test regimes and acceptance criteria. Order to the specification your drawing requires. Tell us which standard governs the part and we will melt, forge, test and certify to that document.
Heat treatment of 1.6354
Heat treatment is two operations, both low-risk. This is the main practical advantage of maraging steel over quench-and-temper grades of similar strength.
| Operation | Temperature | Time | Cooling | Result |
|---|---|---|---|---|
| Solution anneal | 815 – 825 °C 1 500 – 1 520 °F | 1 h per 25 mm of section | Air cool | Soft martensite, 30–35 HRC |
| Age (precipitation harden) | 480 – 485 °C 900 – 905 °F | 3 – 6 h; longer for heavy sections | Air cool | 50–54 HRC, Rp0.2 ≥ 1 862 MPa |
| Stress relief (optional) | ≈ 315 °C / 600 °F | 1 – 2 h | Air cool | Relieves machining stress without ageing |
Practical notes
- No protective atmosphere is required. As 1.6354 is almost carbon-free there is no decarburisation to guard against during annealing or ageing, although vacuum or inert ageing gives a cleaner surface.
- Ageing shrinks the part. Expect about 0.1 % uniform linear contraction. Most shops build this into the CAM offsets and finish-machine before ageing.
- Over-ageing. Excess temperature softens 1.6354 gradually rather than causing a sudden loss of properties. Mis-processed parts can usually be re-solution-annealed and re-aged.
We supply 1.6354 forgings solution-annealed as standard. If they are needed fully aged and ready to grind, state this at enquiry stage and we will quote the ageing cycle and the hardness survey.
How Jiangnan Metal forges 1.6354
1.6354 is an expensive and cleanliness-sensitive alloy. The route below is the one we run at our Zhouzhuang works. Each step protects either cleanliness or grain flow.
| Step | Operation | Why it matters for 1.6354 |
|---|---|---|
| 1 | Melting — VIM + VAR (double vacuum), or EAF + LF + VD + ESR for commercial work | Aerospace specifications generally require the double-vacuum route. The ESR route is a lower-cost option for tooling and industrial parts. |
| 2 | Ingot homogenisation and soaking | Dissolves segregation of Mo and Ti before hot work. |
| 3 | Open-die forging — start ≈ 1 150–1 200 °C, finish above ≈ 850 °C | Breaks down the cast structure and develops directional grain flow along the part axis. |
| 4 | Ring rolling or mandrel expansion, where the part is a ring | Gives continuous circumferential fibre with no cut grain at the bore. |
| 5 | Solution anneal 815–825 °C, air cool | Resets the structure to uniform soft martensite for machining. |
| 6 | Rough machining / proof machining to your allowance | Removes the scaled skin and opens the body for ultrasonic testing. |
| 7 | Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388 | Confirms internal soundness before further machining is added. |
| 8 | Mechanical testing, hardness survey, dimensional inspection | Generates the data reported on the certificate. |
| 9 | Marking, preservation, EN 10204 3.1 / 3.2 certification, packing | Heat number and part identity stay attached to the forging. |
Machining, welding and surface treatment
- Machinability is about 35–40 % of free-machining AISI 1212 in the annealed condition. Standard carbide tooling is suitable. Use rigid setups, positive geometry and generous coolant, and keep feeds steady to avoid work-hardening the surface.
- Weldability is good, which is unusual for a 2 000 MPa steel. No preheat is needed, the low carbon means no hard, crack-prone HAZ, and a post-weld age restores most of the joint strength. Weld in the annealed condition wherever the design allows.
- Corrosion resistance is low. 1.6354 rusts like a low-alloy steel. Specify plating, painting, passivation or nitriding for exposed service, and keep forgings oiled and dry in storage.
- Nitriding is compatible with the ageing cycle and produces a very hard case over an already strong core, which suits wear faces on dies and shafts.
Where 1.6354 forgings are used
1.6354 is specified where a part must carry very high stress in a small envelope, be welded or machined into a complex shape, and hold dimension through hardening. Typical duties for our forgings:
Dies and press tooling
Die-casting dies, hot and cold extrusion dies, forging tools, punches and mandrels, where thermal cycling and shock would crack a conventional tool steel.
Shafts, spindles and couplings
Highly stressed transmission shafts, torsion members, gear blanks and actuator components in motorsport and high-performance drivetrains.
Structural and propulsion parts
Landing-gear components, rocket motor cases, actuator bodies and highly loaded structural fittings, ordered against AMS 6514 or AMS 6521.
Rings, flanges and pressure parts
Seamless rolled rings, flanges, sleeves and blocks for hydraulic, compressor and heavy-machinery assemblies that must not yield.
Springs, fasteners and instruments
Belleville and flat springs, high-strength fasteners, load cells and precision mechanisms that make use of the high elastic limit.
Low-temperature service
Components that must keep notch toughness down to around −50 °C while remaining at full strength.
Export control and compliance. Maraging steels capable of an ultimate tensile strength of 1 950 MPa or more, which includes fully aged 1.6354, are listed as dual-use controlled items under several national and multilateral regimes. Jiangyin Jiangnan Metal supplies this grade for legitimate commercial and industrial applications only, and will request end-user and end-use information on enquiries where it is required. Buyers remain responsible for the import, re-export and end-use rules that apply in their own jurisdiction.
Testing, certification and how to order
What we test and certify
- Chemical analysis: ladle and, on request, product analysis, reported element by element.
- Ultrasonic testing: EN 10228-3, SEP 1921 or ASTM A388, to the quality class you nominate.
- Mechanical testing: tensile, hardness and impact on prolongations or sacrificial test pieces; test-piece location agreed in advance.
- Surface NDT: magnetic particle or dye penetrant inspection where specified.
- Grain size, microstructure and dimensional reports on request.
- Certification: EN 10204 3.1 as standard; EN 10204 3.2 with third-party witness (SGS, BV, TÜV, Lloyd's and similar) when the project requires it.
Sending an enquiry
A drawing gives the most accurate price. Without one, the six items below are enough for us to quote.
| # | What to send | Example |
|---|---|---|
| 1 | Grade and governing specification | 1.6354 to AMS 6514 |
| 2 | Shape and finished dimensions, or a drawing (PDF / STEP / DWG) | Rolled ring, OD 620 × ID 420 × H 180 mm |
| 3 | Quantity and expected repeat volume | 4 pcs, repeating twice a year |
| 4 | Delivery condition | Solution annealed, rough machined, +3 mm allowance |
| 5 | Testing and certificate level | UT to EN 10228-3 class 3, EN 10204 3.1 |
| 6 | Destination port and required delivery date | Rotterdam, week 42 |
Send it to sales@steelforgepieces.com or call 0086-189-2135-9659. Drawings are treated as confidential and are not passed outside our engineering and production team.
Frequently asked questions about 1.6354
What is 1.6354 steel?
1.6354 is the European material number for X2NiCoMo18-9-5, an 18 % nickel–cobalt–molybdenum maraging steel known internationally as Maraging 300 or 18Ni(300). It contains almost no carbon and gains its strength from Ni3Mo and Ni3Ti precipitates formed during a low-temperature ageing treatment at 480 °C, reaching a yield strength above 1 862 MPa (270 ksi).
Is 1.6354 the same as Maraging 300 or Vascomax C300?
They refer to the same 18Ni(300) maraging steel. 1.6354 is the Werkstoff number, X2NiCoMo18-9-5 the EN name, K93120 the UNS number, AMS 6514 the aerospace bar and forging specification, and Maraging 300, M300, C300 and Vascomax C300 are common or proprietary trade names. The closely related number 1.6358 covers the titanium-bearing variant. Because acceptance criteria differ between standards, order to the specification your drawing calls out rather than to a trade name.
What is the difference between 1.6354 (Maraging 300) and 1.6359 (Maraging 250)?
Grade 300 carries more cobalt, molybdenum and titanium, so it ages to a higher strength, roughly 2 000 MPa tensile against about 1 700 MPa for grade 250. The trade-off is fracture toughness: Maraging 250 is tougher and more tolerant of defects. Choose 300 when the design is strength-limited and 250 when it is damage-tolerance-limited. Jiangyin Jiangnan Metal forges both.
What is the chemical composition of 1.6354?
Nominally: carbon 0.03 % max, silicon 0.10 % max, manganese 0.10 % max, sulphur and phosphorus 0.010 % max each, nickel 18.0–19.0 %, cobalt 8.0–9.5 %, molybdenum 4.6–5.2 %, titanium 0.55–0.80 %, aluminium 0.05–0.15 %, balance iron. See Table 1 above for the full breakdown with each element's role.
What strength does 1.6354 reach after ageing?
After ageing at 480 °C for 3–6 hours followed by air cooling, 1.6354 typically reaches 1 930–2 050 MPa tensile strength, a 0.2 % proof strength of at least 1 862 MPa (270 ksi), 6–10 % elongation and 50–54 HRC. AMS 6514 sets the minima; the certificate issued with each Jiangnan Metal forging reports the values actually measured on your heat.
How is 1.6354 heat treated?
Two steps. Solution anneal at 815–825 °C for about one hour per 25 mm of section and air cool, which gives a soft martensite at 30–35 HRC. Then age at 480–485 °C for 3–6 hours and air cool. No quenching medium and no protective atmosphere are strictly required, because the alloy is essentially carbon-free.
Does 1.6354 distort or change size when it is hardened?
Very little. Ageing produces roughly 0.1 % uniform linear contraction and no quench distortion, because nothing is quenched and no phase transformation occurs. Many shops finish-machine in the annealed condition, apply a calculated offset for the shrinkage, and age as the last operation. This is one reason 1.6354 is used for precision tooling.
Can 1.6354 be welded?
Yes. Weldability is good for a steel of this strength. The very low carbon content means the heat-affected zone does not form brittle martensite, so no preheat is required. Weld in the solution-annealed condition where possible and age the assembly afterwards to recover strength across the joint. Use matching filler and keep the weld area clean.
Is 1.6354 corrosion resistant or stainless?
No. Despite its high nickel content, 1.6354 has no chromium and corrodes much like an ordinary low-alloy steel. Protect it with plating, painting, phosphating or nitriding for service, and keep forgings oiled and dry in transit and storage. Where corrosion resistance is essential, a precipitation-hardening stainless such as PH13-8Mo or 17-4 PH is usually the better choice.
What forged shapes can you supply in 1.6354?
Jiangyin Jiangnan Metal produces 1.6354 as seamless rolled rings, forged rings, flanges, discs and disks, round bar and billet, shafts and eccentric shafts, spindles, sleeves, bushings, forged tubes and hollows, tube sheets, blocks and near-net preforms. Everything is made to drawing. Send your geometry and we will confirm feasibility and machining allowances.
What certificates come with a 1.6354 forging?
EN 10204 3.1 certification is standard, covering chemical analysis, mechanical test results, heat-treatment record, ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, and dimensional confirmation. EN 10204 3.2 with third-party witness (SGS, BV, TÜV, Lloyd's Register and similar) is available on request.
Is 1.6354 subject to export control?
Maraging steels capable of 1 950 MPa or more ultimate tensile strength appear on dual-use control lists in several jurisdictions, and fully aged 1.6354 falls in that range. Jiangyin Jiangnan Metal supplies the grade for legitimate commercial and industrial use and may request end-user and end-use information. Buyers should confirm the import, re-export and end-use rules applying in their own country before placing an order.
Who forges 1.6354 in China, and what are the lead times?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, producing 1.6354 forgings to customer drawings. Lead time depends on ingot availability, part size and the testing scope, so it is confirmed with each quotation. Email sales@steelforgepieces.com or call 0086-189-2135-9659.
Reference and citation
This page is maintained as a working reference for 1.6354. If you quote it in a specification, report or tender document, please cite it as:
Jiangyin Jiangnan Metal Co., Ltd. (2026). "1.6354 Forgings, X2NiCoMo18-9-5 / Maraging 300: composition, properties, heat treatment and forged product forms." Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Nickel-Alloy/1.6354.html (reviewed 7 August 2026).
Sources for the property values: AMS 6514 and AMS 6521 minima, published producer datasheets for 18Ni(300) maraging steel, and our own production and test records. Figures described as typical are indicative rather than guaranteed. The mill test certificate governs.