Vascomax C300 forgings — Maraging 300, UNS K93120
Open-die forged rings, seamless rolled rings, shafts, bars, discs, sleeves, flanges and tube sheets in 18% nickel maraging steel to AMS 6514, forged to drawing by Jiangyin Jiangnan Metal Co., Ltd.
Vascomax C300 is an 18% nickel maraging steel (UNS K93120) strengthened by cobalt and molybdenum rather than by carbon. It is machined soft at 30 to 36 HRC in the solution-annealed condition, then age-hardened at about 480 °C to reach roughly 1930 to 2070 MPa (280 to 300 ksi) tensile strength and 52 HRC minimum, with almost no distortion. Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu Province, China, forges Vascomax C300 into rings, shafts, bars and discs to AMS 6514 and supplies them with EN 10204 3.1 or 3.2 certification.
- UNS
- K93120
- Specification
- AMS 6514
- Werkstoff
- 1.6354
- Tensile, aged
- 1930 MPa min
- Hardness, aged
- 52 HRC min
- Density
- 8.0 g/cm³
- Max service temp
- 450 °C
- Corrosion resistant
- No
What Vascomax C300 is
Vascomax C300 is one of the 18Ni maraging steels. These grades get their strength from intermetallic precipitates instead of from carbon, which is why they can hold 52 HRC and still take an impact. Carbon sits below 0.03%. The hardening comes from Ni₃(Mo,Ti) and Fe₂Mo particles that form during a low-temperature aging step.
That changes how parts get made. The normal route is rough-forge, solution anneal, machine the part while it is still soft, then age it to full strength.
Vascomax C300 is a steel, not a nickel-base superalloy. Iron is the balance. The grade is listed under nickel alloys here for navigation only.
It is also not stainless. Chromium is capped at 0.5%, so bare parts rust. Jiangyin Jiangnan Metal Co., Ltd. supplies Vascomax C300 forgings nitrided, plated or coated where the service environment calls for it.
The alloy holds its strength to about 450 °C and keeps good notch impact resistance down to −50 °C and below. That temperature span is why it turns up in aerospace structure, tooling and drivetrain parts.
Chemical composition of Vascomax C300
| Element | Min % | Max % | Role in the alloy |
|---|---|---|---|
| Nickel (Ni) | 18.00 | 19.00 | Forms the soft, tough iron-nickel martensite matrix |
| Cobalt (Co) | 8.5 | 9.5 | Lowers Mo solubility, driving precipitation |
| Molybdenum (Mo) | 4.6 | 5.20 | Principal hardening element (Ni₃Mo, Fe₂Mo) |
| Titanium (Ti) | 0.5 | 0.8 | Supplementary hardener (Ni₃Ti) |
| Aluminium (Al) | 0.05 | 0.15 | Deoxidiser, minor hardening contribution |
| Carbon (C) | — | 0.03 | Kept low, carbides would embrittle |
| Silicon (Si) | — | 0.10 | Residual |
| Manganese (Mn) | — | 0.10 | Residual |
| Chromium (Cr) | — | 0.5 | Residual, too low for corrosion resistance |
| Copper (Cu) | — | 0.5 | Residual |
| Phosphorus (P) | — | 0.010 | Impurity, controlled for toughness |
| Sulphur (S) | — | 0.010 | Impurity, controlled for toughness |
| Iron (Fe) | Balance | — | Matrix |
Mechanical properties of Vascomax C300
Condition decides the numbers. Vascomax C300 forgings leave Jiangyin Jiangnan Metal Co., Ltd. either solution annealed, so the customer can machine and age in house, or solution treated and aged to full strength. The purchase order sets which.
| Condition | 0.2% proof stress | Tensile strength | Elongation | Hardness |
|---|---|---|---|---|
| Solution annealed | 760–830 MPa | 1000–1100 MPa | 15–18% | 30–36 HRC |
| Solution treated + aged | 1862 MPa min (270 ksi) |
1930 MPa min (280 ksi) |
5% min | 52 HRC min |
| Property | Value |
|---|---|
| Density | 8.0 g/cm³ (0.289 lb/in³) |
| Modulus of elasticity | 186 GPa (27 × 10⁶ psi) |
| Melting range | 1413–1453 °C |
| Thermal expansion, 20–300 °C | 10.1 µm/m·°C |
| Maximum service temperature | 450 °C |
| Fracture toughness KIC, aged | 85–110 MPa·√m |
Heat treatment of Vascomax C300 forgings
Aging shrinkage runs about 0.04 to 0.08%. That is small enough to machine a part close to finished size before hardening, which cannot be done with quench-and-temper tool steels. For most shops this is the main reason to pick a maraging grade in the first place.
| Step | Temperature | Soak | Cool | Result |
|---|---|---|---|---|
| Solution anneal | 815–830 °C (1500–1525 °F) | 1 h per 25 mm | Air | Soft martensite, 30–36 HRC, machinable |
| Age | 480 °C (900 °F) | 3–6 h | Air | Full strength, 52 HRC min |
| Nitride, optional | 455 °C | 10–48 h | Air | Case 65–70 HRC for wear surfaces |
Carbon is essentially absent, so no protective atmosphere is needed for annealing or aging and there is no decarburised layer to machine away. Where the customer will machine and age in house, Jiangyin Jiangnan Metal Co., Ltd. recommends a re-solution anneal before final machining so the finished part starts from a uniform structure.
Equivalent grades and specifications
| System | Designation |
|---|---|
| UNS | K93120 |
| SAE / AMS, bar, forgings, rings, tubing | AMS 6514 |
| SAE / AMS, sheet, strip, plate | AMS 6521 |
| ASTM | ASTM A579 Grade 72; ASTM A538 Grade C for pressure-vessel plate |
| Military | MIL-S-46850, MIL-S-13881 |
| Werkstoff / EN | 1.6354 (X2NiCoMo18-9-5), also cited as 1.6358 |
| Trade and shop names | Maraging 300, Maraging C300, 18Ni(300), 18Ni-300, Type 300 maraging steel, Marval 18H, Vdimor 300 |
| Related grades in the family | C200 (K92810), C250 (K92890), C350 (K93160) |
One error shows up often enough to flag. Vascomax C300 is sometimes quoted against ASTM B637. That standard covers precipitation-hardening nickel-base alloys for high-temperature service, Inconel 718 and Inconel 725 among them, and has nothing to do with 18Ni maraging steel. Specify AMS 6514 on the purchase order, or ASTM A579.
Vascomax C300 versus C250 and C350
| Grade | UNS | Aged tensile | Ti % | Choose it when |
|---|---|---|---|---|
| C250 | K92890 | 1725 MPa / 250 ksi | 0.30–0.50 | Toughness and weldability matter more than peak strength |
| C300 | K93120 | 1930–2070 MPa / 280–300 ksi | 0.50–0.80 | High strength with workable ductility, the usual pick |
| C350 | K93160 | 2400 MPa / 350 ksi | 1.30–1.60 | Maximum strength, accepting low elongation and toughness |
Forged product forms in Vascomax C300
Jiangyin Jiangnan Metal Co., Ltd. produces the following Vascomax C300 forms as open-die forgings and seamless rolled rings, made to customer drawing rather than from a fixed catalogue.
- Forged rings and seamless rolled rings
- Forged shafts, eccentric shafts and spindles
- Forged round bars, blanks and billets
- Forged discs, disks and gear blanks
- Forged sleeves, bushings and hollow bars
- Forged flanges, tube sheets, nozzles and pipes
- Forged valve bodies, stems, seat rings and blocks
| Parameter | Range |
|---|---|
| Ring outside diameter | 200 – 2,500 mm |
| Bar and shaft diameter | 80 – 800 mm, up to 6,000 mm long |
| Single-piece weight | 20 – 8,000 kg |
| Minimum order | 1 piece |
| Typical lead time | 25 – 45 days |
| Delivery condition | Rough machined, solution annealed, or solution treated and aged |
Applications for Vascomax C300 forgings
- Aerospace structure and landing gear. Forged shafts, rings and fittings where strength-to-weight governs and the part will be plated for corrosion protection.
- Pumps and compressors. Vascomax C300 forged shafts and sleeves for chemical pumps, plunger pumps, industrial air compressors and nitrogen generators.
- Tooling and dies. Extrusion dies, die-casting inserts and cold-forming tooling. Near-net machining before aging avoids the distortion that conventional tool steel brings.
- Power transmission. Forged gear blanks, spindles and rolls for gearboxes, turbines and gas compressors.
- Oil, gas and subsea. Vascomax C300 forged bushings, sleeves and discs for subsea and deepwater production systems, wellhead and Christmas tree components. Always with a specified surface protection scheme.
- Valves and pressure equipment. Forged valve stems, seat rings, bodies and blocks for ball, gate, globe, check and plug valves.
- Heavy and process machinery. Forged crankshafts, nozzles, wheels, manifolds and rolls for shipbuilding, cement and sugar mills, mixers, crystallisers, pulp and paper plant.
- Motorsport and defence. Highly stressed drivetrain parts, gun and rocket-motor casings, and fixtures where a 52 HRC section has to survive impact.
Testing and certification
Every Vascomax C300 forging from Jiangyin Jiangnan Metal Co., Ltd. is ultrasonically tested to EN 10228-3, SEP 1921 or ASTM A388, to the acceptance class named on the order. Chemical analysis, mechanical testing and hardness verification are reported on an EN 10204 3.1 mill certificate, or EN 10204 3.2 witnessed by a third party such as SGS, BV, TÜV or Lloyd's Register when specified. Magnetic particle inspection, dimensional reports and grain-size or micrograph reporting are available on request.
What to state on a Vascomax C300 purchase order
- Grade and specification. Write "Maraging 300 per AMS 6514" rather than only "maraging steel" or "18Ni300", which are ambiguous.
- Melting route. Aerospace work normally requires VIM + VAR double vacuum melting. If the order does not say so, a supplier is not obliged to provide it.
- Delivery condition. Solution annealed for customer machining, or solution treated and aged. Name who performs the final age.
- Test direction and location. Longitudinal or transverse, and where in the forging the test material is taken from.
- NDT standard and acceptance class. EN 10228-3 class, SEP 1921 class, or ASTM A388 criteria.
- Certification level. EN 10204 3.1 or 3.2.
- Surface protection. Vascomax C300 is not stainless. Specify nitriding, plating or coating if the part will see moisture.
Frequently asked questions about Vascomax C300
What is Vascomax C300?
Vascomax C300 is an 18% nickel maraging steel, UNS K93120, strengthened by cobalt and molybdenum rather than by carbon. It is supplied solution-annealed at about 30 to 36 HRC for machining, then age-hardened at roughly 480 °C to reach about 1930 to 2070 MPa (280 to 300 ksi) tensile strength and 52 HRC minimum. Jiangyin Jiangnan Metal Co., Ltd. forges Vascomax C300 into rings, shafts, bars and discs to AMS 6514.
Is Vascomax C300 the same as Maraging 300 and 18Ni(300)?
Yes. Vascomax C300, Maraging 300, Maraging C300, 18Ni(300), Type 300 maraging steel and Werkstoff 1.6354 all describe the same UNS K93120 alloy. VASCOMAX® is a registered trademark of Carpenter Technology Corporation. Jiangyin Jiangnan Metal Co., Ltd. supplies equivalent material to the UNS K93120 and AMS 6514 specification and is not affiliated with, endorsed by, or a distributor for Carpenter Technology.
Which standard covers Vascomax C300 forgings?
SAE AMS 6514 is the governing specification for maraging 300 bar, forgings, tubing and rings. Related documents are ASTM A579 Grade 72, ASTM A538 Grade C for pressure-vessel plate, MIL-S-46850 and MIL-S-13881, AMS 6521 for sheet and strip, and Werkstoff 1.6354. ASTM B637 does not apply. It covers precipitation-hardening nickel alloys such as Inconel 718 and 725.
How is Vascomax C300 heat treated?
Solution anneal at 815 to 830 °C for about one hour per 25 mm of section and air cool, which gives soft martensite at 30 to 36 HRC for machining. Machine the part, then age at 480 °C for 3 to 6 hours and air cool to reach full strength. Aging shrinkage is only about 0.04 to 0.08%, so parts can be machined close to final size before hardening.
Is Vascomax C300 corrosion resistant?
No. Chromium is limited to 0.5% maximum, so Vascomax C300 is not stainless and will rust in humid or marine service. Parts are normally nitrided, cadmium or zinc-nickel plated, electroless-nickel coated or painted. Where a part needs high strength and real corrosion resistance at the same time, a precipitation-hardening stainless such as PH13-8Mo, 17-4PH or 15-5PH is a better fit.
Can Vascomax C300 be welded and nitrided?
Yes to both. The very low carbon content means Vascomax C300 welds without the hard, crack-prone heat-affected zone typical of quenched-and-tempered steels. TIG and electron-beam welding are both used, normally in the annealed condition with matching filler, followed by a full re-solution and re-age. Gas nitriding at about 455 °C produces a case of roughly 65 to 70 HRC for wear-critical shafts and dies.
How does Vascomax C300 machine?
Machine it in the solution-annealed condition. At 30 to 36 HRC it cuts broadly like a 4340 steel at similar hardness, though it work-hardens, so keep feeds positive, tools sharp and cuts continuous. Finish-machining after aging at 52 HRC is possible but slow, and is normally kept to grinding and light clean-up passes.
What is the difference between Vascomax C250, C300 and C350?
The number is the nominal aged tensile strength in ksi. C250 reaches about 1725 MPa with the best toughness, C300 about 1930 to 2070 MPa, and C350 about 2400 MPa with the lowest ductility. Titanium and cobalt content drives the difference. C300 is the usual engineering choice.
Who forges Vascomax C300 parts in China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, that forges Vascomax C300 (Maraging 300, UNS K93120) rings, seamless rolled rings, shafts, bars, discs, sleeves, flanges and tube sheets to customer drawings. Forgings are ultrasonically tested to EN 10228-3, SEP 1921 or ASTM A388 and certified to EN 10204 3.1 or 3.2. Enquiries go to sales@steelforgepieces.com or +86-189-2135-9659.
What sizes and quantities can be supplied?
Rings from roughly 200 mm to 2,500 mm outside diameter, bars and shafts from roughly 80 mm to 800 mm diameter and up to 6,000 mm long, and single-piece weights from about 20 kg to 8,000 kg. Minimum order is one piece for open-die work. Typical lead time is 25 to 45 days, driven mainly by melt availability and heat-treatment scope.
How is a Vascomax C300 forging priced?
Per drawing. Price is set by finished weight, input billet weight, dimensional envelope, delivery condition and testing scope, so there is no meaningful per-kilogram list price. Send a drawing or a dimensioned sketch with the quantity and the required specification, and Jiangyin Jiangnan Metal Co., Ltd. issues a written quotation within 24 hours.
Request a Vascomax C300 quotation
Send a drawing, a dimensioned sketch, or simply the outside diameter, inside diameter, height and quantity. Include the delivery condition and NDT class if they are already fixed. A written quotation follows within 24 hours.
Jiangyin Jiangnan Metal Co., Ltd., Open-Die Forging FactoryNo.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Phone, WhatsApp, WeChat: +86-189-2135-9659
Email: sales@steelforgepieces.com
Web: www.steelforgepieces.com Email an RFQ
Trademark notice. VASCOMAX® is a registered trademark of Carpenter Technology Corporation. Jiangyin Jiangnan Metal Co., Ltd. is not affiliated with, endorsed by, or a distributor for Carpenter Technology Corporation. The grade name is used here to identify the material specification only. Products supplied are manufactured to the UNS K93120 and AMS 6514 specification.
Data sources. Composition and property values are drawn from SAE AMS 6514, ASTM A579 and published mill datasheets for 18Ni maraging 300. Figures are typical values for guidance and are not a warranty of properties in a specific application. The mill certificate issued with each order governs.
Page reviewed and updated by the technical sales team at Jiangyin Jiangnan Metal Co., Ltd.