Maraging steel forgings · Technical datasheet
UNS K92890 Forgings (Maraging 250)
Maraging 250 · 18Ni(250) · C250 · AMS 6512 · W.Nr. 1.6359. Seamless rolled rings, discs, shafts, flanges, bushings and round bars
UNS K92890 is 18 percent nickel maraging steel of the 250 grade. It is a low-carbon iron-nickel-cobalt-molybdenum alloy, hardened by ageing at about 480 °C instead of quenching, that reaches at least 1758 MPa (255 ksi) tensile strength and 48 HRC with very little distortion. Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, forges UNS K92890 to AMS 6512 chemistry into seamless rolled rings, discs, shafts, flanges, sleeves, bushings, tube sheets and round bars, supplied annealed for machining or fully maraged, ultrasonically tested and certified to EN 10204 3.1 or 3.2.
- UNSK92890
- Werkstoff1.6359
- SpecificationAMS 6512
- Tensile, aged≥ 1758 MPa
- Hardness, aged≥ 48 HRC
- Density8.0 g/cm³
What is UNS K92890?
UNS K92890 is the Unified Numbering System designation for 18 percent nickel maraging steel of the 250 grade, written in industry as Maraging 250, 18Ni(250) or C250. The name comes from the words martensitic and ageing. The alloy is hardened by precipitating nanometre-scale intermetallics out of an already martensitic matrix rather than by quenching carbon into solution.
Carbon is deliberately held to 0.03 percent maximum. Strength comes from nickel at 17.0 to 19.0 percent, cobalt at 7.0 to 8.5 percent, molybdenum at 4.6 to 5.2 percent and titanium at 0.30 to 0.50 percent, which form Ni3Mo, Ni3Ti and Fe2Mo precipitates during ageing near 480 °C. Because there is no carbon to trap, the alloy air cools to a soft, tough, dislocated iron-nickel martensite at roughly 28 to 32 HRC after annealing, and stays fully machinable and weldable in that state.
This two-stage behaviour is why the grade is used. A part can be forged, annealed, machined close to final size and welded while it is soft, then aged in a low-temperature furnace with no quench, no oil, no cracking risk and a contraction of only about 0.04 percent. The 250 in the name is the minimum yield strength in the aged condition, 250 ksi or 1724 MPa.
Jiangyin Jiangnan Metal Co., Ltd. supplies UNS K92890 as forged product only, that is open-die forgings and seamless rolled rings. Forging closes porosity from the ingot and aligns grain flow with the principal stress direction, which matters in fatigue-loaded shafts and pressure-retaining rings.
UNS K92890 designations and equivalent specifications
The same 250-grade chemistry appears under a long list of national, military and proprietary names. All of the following describe material that Jiangyin Jiangnan Metal Co., Ltd. can forge and certify.
| System | Designation | Scope |
|---|---|---|
| UNS (USA) | K92890 | Numbering designation for the 250-grade 18Ni maraging steel |
| SAE / AMS | AMS 6512 | Bar and forging stock, vacuum melted, annealed. The usual controlling specification |
| Werkstoff (DE) | 1.6359 | German material number for the 250 grade |
| ASTM | A538 Grade B | Precipitation-hardening maraging steel plate, sheet and strip |
| US military | MIL-S-46850, grade 250 | 18 percent nickel maraging steel, plate, sheet, strip, bar, forgings |
| UK | BS S162, DTD 5212, MSRR 6551 | British aerospace bar, billet and forging specifications |
| Other aerospace | MAT 102, MIA 101 | Company and airframe specifications calling the same grade |
| Common names | Maraging 250, 18Ni(250), C250, Alloy 250 | Generic industry usage for the grade |
| Trade names | Vascomax® C250, Udimar® 250 | Proprietary names of other producers for the same chemistry |
| Sister grades | K92810 (200), K93120 (300), K93160 (350) | Lower and higher strength members of the 18Ni maraging family |
Table compiled by Jiangyin Jiangnan Metal Co., Ltd. from published specification listings. There is no direct EN, JIS or GB grade that is fully interchangeable with UNS K92890; purchase against AMS 6512 or against your own drawing specification.
Why UNS K92890 is specified
- Ultra-high strength with usable toughness. At least 1758 MPa (255 ksi) tensile and 1724 MPa (250 ksi) yield in the maraged condition, with a fracture toughness that is well above quenched and tempered steels at the same strength level.
- Dimensional stability through hardening. Ageing is an air-cooled furnace cycle at 480 °C. There is no quench, so there is no quench distortion and no quench cracking; the part contracts by roughly 0.04 percent, uniformly and predictably.
- Machining is done in the soft condition. Annealed material at 28 to 32 HRC is cut with conventional carbide tooling, which removes the cost and risk of machining fully hardened steel.
- Weldable without preheat. With carbon at 0.03 percent maximum there is no hard martensitic heat-affected zone to crack, so fabrication and repair are straightforward.
- Good resistance to stress-corrosion cracking compared with conventional ultra-high-strength steels of the same tensile level, and low notch sensitivity in thick sections.
- Resistance to crack propagation under cyclic load, which is why the grade is used in rocket motor cases, drive shafts, slat tracks and ejector systems.
Where UNS K92890 is the wrong choice
The grade contains only residual chromium, up to 0.50 percent, so it is not stainless and it corrodes in damp air like a low-alloy steel; parts are plated, painted or otherwise protected. It should not be used above about 400 °C in continuous service, because the strengthening precipitates coarsen as the metal approaches its own 480 °C ageing temperature. It costs several times a quenched and tempered alloy steel because of the cobalt, nickel and molybdenum content and the vacuum melting route. For hot service use Inconel 718 or Waspaloy; for corrosive service at high strength use PH13-8Mo or 17-4PH.
UNS K92890 compared with Maraging 300 and AISI 4340
Two comparisons come up in almost every enquiry. The first is which maraging grade to use. The second is whether a maraging steel is worth the price over a quenched and tempered alloy steel.
| Attribute | Maraging 250 (K92890) | Maraging 300 (K93120) | AISI 4340, Q&T |
|---|---|---|---|
| Nickel | 17.0-19.0 % | 18.0-19.0 % | 1.65-2.00 % |
| Cobalt | 7.0-8.5 % | 8.5-9.5 % | not present |
| Titanium | 0.30-0.50 % | 0.55-0.80 % | not present |
| Carbon | 0.03 % max | 0.03 % max | 0.38-0.43 % |
| Tensile, hardened | ≥ 1758 MPa | ≥ 1931 MPa | ≈ 1790 MPa at low temper |
| Hardening route | Age 480 °C, air cool | Age 480 °C, air cool | Austenitise 845 °C, oil quench, temper |
| Distortion on hardening | Very low, ≈ 0.04 % uniform contraction | Very low, similar | Significant; quench cracking risk in complex shapes |
| Toughness at strength | High | Moderate; falls as strength rises | Lower at equivalent tensile |
| Weldability | Good, no preheat | Good, more segregation-sensitive | Poor; preheat and PWHT required |
| Decarburisation risk | None of consequence | None of consequence | Real; requires machining allowance |
| Corrosion resistance | Low, protect the surface | Low, protect the surface | Low, protect the surface |
| Relative cost | High | Higher | Low |
| Best use | Fatigue and fracture-critical parts, large or complex sections | Strength-limited parts in small sections, tooling | General high-strength machinery where cost governs |
Table compiled by Jiangyin Jiangnan Metal Co., Ltd. from published alloy specifications. Values for AISI 4340 are typical for a low tempering temperature and are shown for order-of-magnitude comparison only.
Chemical composition of UNS K92890
The table below is the specification range that Jiangyin Jiangnan Metal Co., Ltd. forges to, matching AMS 6512. Every heat is supplied with a ladle analysis on the mill certificate; product analysis on the finished forging can be added on request.
| Element | Symbol | Weight % | Function in the alloy |
|---|---|---|---|
| Nickel | Ni | 17.0-19.0 | Forms the low-carbon iron-nickel martensite matrix |
| Cobalt | Co | 7.0-8.5 | Lowers molybdenum solubility, driving precipitation on ageing |
| Molybdenum | Mo | 4.6-5.2 | Principal hardener; forms Ni3Mo and Fe2Mo |
| Titanium | Ti | 0.30-0.50 | Secondary hardener; forms Ni3Ti |
| Aluminium | Al | 0.05-0.15 | Deoxidation and a small ageing contribution |
| Carbon | C | 0.03 max | Kept low to avoid carbides that would embrittle the matrix |
| Manganese | Mn | 0.10 max | Residual, controlled |
| Silicon | Si | 0.10 max | Residual, controlled |
| Sulphur | S | 0.010 max | Impurity limit; low sulphur protects toughness |
| Phosphorus | P | 0.010 max | Impurity limit |
| Chromium | Cr | 0.50 max | Residual only, so the grade is not stainless |
| Copper | Cu | 0.50 max | Residual |
| Iron | Fe | Balance | Matrix |
Source: Jiangyin Jiangnan Metal Co., Ltd., UNS K92890 forging specification, aligned to AMS 6512.
Mechanical properties of forged UNS K92890
Two conditions matter commercially. Annealed material is machined and welded, and maraged material carries the load. Values in the maraged row are the certified room-temperature minima; results on the mill certificate normally sit above them.
| Property | Annealed (typical) | Maraged 480 °C / 900 °F (minimum) | Test method |
|---|---|---|---|
| Ultimate tensile strength | ≈ 965-1035 MPa (140-150 ksi) | 1758 MPa (255 ksi) | ASTM E8 / ISO 6892-1 |
| Yield strength, 0.2 % offset | ≈ 760-825 MPa (110-120 ksi) | 1724 MPa (250 ksi) | ASTM E8 / ISO 6892-1 |
| Elongation in 4D | ≈ 15-19 % | 6 % | ASTM E8 |
| Reduction of area | ≈ 70 % | Typically 40-55 % | ASTM E8 |
| Hardness | ≈ 28-32 HRC | ≥ 48 HRC | ASTM E18 |
| Modulus of elasticity | ≈ 186 GPa | ≈ 190 GPa (27.5 × 106 psi) | Dynamic method |
| Fracture toughness KIC | not applicable | Commonly reported near 100 MPa·m½ | ASTM E399, when ordered |
| Grain size | ASTM 5 or finer | ASTM 5 or finer | ASTM E112 |
Source: Jiangyin Jiangnan Metal Co., Ltd. Maraged minima follow AMS 6512. Annealed figures, reduction of area and fracture toughness are typical published values for the 250 grade, given for design guidance; they are not certified minima unless written into the order. Fracture toughness is section, direction and process dependent and is only certified when KIC testing is specified.
Physical and thermal properties
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.00 g/cm³ | 0.289 lb/in³ |
| Melting range | ≈ 1413-1440 °C | ≈ 2575-2625 °F |
| Modulus of elasticity, maraged | ≈ 190 GPa | ≈ 27.5 × 106 psi |
| Coefficient of thermal expansion, 20-100 °C | ≈ 10.1 µm/m·°C | ≈ 5.6 µin/in·°F |
| Thermal conductivity, 20 °C | ≈ 18-20 W/m·K | ≈ 125-139 BTU·in/hr·ft²·°F |
| Specific heat capacity | ≈ 460 J/kg·K | ≈ 0.11 BTU/lb·°F |
| Electrical resistivity, annealed | ≈ 0.6 µΩ·m | ≈ 360 Ω·circ mil/ft |
| Dimensional change on ageing | ≈ 0.04 % contraction, uniform | ≈ 0.0004 in/in |
| Magnetic response | Ferromagnetic in both the annealed and the maraged condition | |
| Practical service limit | ≈ 400 °C | ≈ 750 °F |
Source: Jiangyin Jiangnan Metal Co., Ltd., consolidated from published 18Ni-250 maraging steel datasheets. Physical constants vary slightly with condition and heat; confirm the contraction figure on a first-article part before committing tight tolerances.
Heat treatment of UNS K92890 and the process temperature map
The heat-treatment route is short. The material is annealed, machined and then aged. Both furnace cycles are air cooled, so there is no quench medium, no distortion allowance for warping and no cracking risk in complex sections.
| Step | Temperature | Soak | Cooling | Result |
|---|---|---|---|---|
| Homogenise (heavy sections only) | ≈ 1150 °C (2100 °F) | 1 h | Air cool | Disperses segregation before re-annealing |
| Solution anneal | 815 °C ± 15 (1500 °F) | 1 h per 25 mm, 1 h minimum | Air cool | Soft iron-nickel martensite, 28-32 HRC |
| Marage (age) | 480 °C ± 6 (900 °F) | 3-6 h | Air cool | ≥ 48 HRC, ≥ 1758 MPa tensile |
| Over-ageing to avoid | above ≈ 510 °C | not applicable | not applicable | Reverted austenite forms and strength falls |
Source: Jiangyin Jiangnan Metal Co., Ltd. Calibrated furnaces to AMS 2750 practice; time-and-temperature charts for the whole load are issued with the mill certificate.
Practical points that affect your part
- Ageing time can be varied. Longer soaks inside the 3 to 6 hour band raise hardness slightly and reduce ductility. Tell us which end of the property range your drawing needs.
- Section thickness barely matters for through-hardening. Because hardening is a precipitation reaction rather than a quench transformation, a 300 mm shaft ages through-section as fully as a 30 mm bar.
- Clean the surface before ageing. Oil, cutting fluid and fingerprints bake on at 480 °C and complicate later plating or inspection.
- Do not stress relieve at conventional steel temperatures. Anything in the 500 to 700 °C range will over-age or partially re-austenitise the structure.
How Jiangyin Jiangnan Metal forges UNS K92890
The route below is what runs for every UNS K92890 order. Each stage generates a record that goes into the documentation pack.
Melt route and billet sourcing
Maraging steel is bought only against documented vacuum practice. VIM plus VAR double melting is used for AMS 6512 and aerospace work, or VIM plus ESR where the end use allows it. Vacuum melting keeps carbon, sulphur, phosphorus, oxygen and nitrogen down to the levels the grade requires. Single-melt air material is not accepted.
Billet preparation and pre-heat
Surfaces are conditioned and the billet is soaked to a uniform through-temperature. Under-soaked nickel-cobalt material cracks on the first blow.
Open-die forging, 1150 down to 900 °C
Hammer and hydraulic press forging with controlled reduction ratios and reheats. Forging is finished above 900 °C and the piece is air cooled. Grain flow is directed along the hoop in rings and along the axis in shafts.
Ring rolling or upsetting to shape
Seamless rings are pierced and rolled to the finished envelope; discs are upset and punched. Both routes give continuous, unbroken grain flow, which is the reason a rolled ring outperforms a ring cut from plate.
Solution annealing
815 °C in calibrated furnaces with recorded charts for the whole charge, then air cool to soft martensite ready for machining.
Rough or finish machining
Supplied as-forged, rough machined to an agreed allowance, or finish machined to drawing tolerance, which is the usual choice for maraging steel because the ageing step barely moves the dimensions.
Maraging, when ordered in the aged condition
480 °C for 3 to 6 hours, air cooled, with the furnace chart issued against the heat number.
Non-destructive and mechanical testing
Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388; PT or MT as specified; tensile, hardness and grain size taken from integral or separately forged prolongations.
Marking, certification and packing
Hard-stamped heat number and part identification, EN 10204 3.1 certificate or 3.2 counter-signed by a third party such as TÜV, BV, SGS or Lloyd's Register, then seaworthy packing for export.
Machining, welding and surface protection
Machining
Machine in the annealed condition at 28 to 32 HRC. Cutting behaviour is close to quenched and tempered alloy steel at the same hardness: rigid set-ups, sharp carbide tooling, positive rake, generous coolant, and moderate speeds with a heavier feed rather than a light rubbing cut. Because ageing contracts the part by only about 0.04 percent, most features can be finished before hardening; leave stock only where the tolerance is tighter than that contraction, and grind or hone after ageing.
Welding
Weldability is one of the main reasons this grade is used. With 0.03 percent maximum carbon there is no hard, crack-sensitive heat-affected zone, so no preheat is required. Weld in the annealed condition with matching filler, keep heat input moderate and the joint clean, then age the assembly at 480 °C. Where the weld region has segregated, a full solution anneal at 815 °C before ageing restores properties. Post-weld ageing recovers most of the joint strength, which is why the grade is used for welded rocket motor cases and fabricated tooling.
Surface protection and hydrogen
UNS K92890 is not corrosion resistant. Protect finished parts by nitriding, plating, painting or phosphating according to the service environment. Like every ultra-high-strength steel it is sensitive to hydrogen, so any acid pickling, electroplating or cathodic cleaning must be followed by a hydrogen-embrittlement relief bake to your process specification. Nitriding is an option where a hard, wear-resistant case is wanted, since the nitriding temperature sits close to the ageing temperature.
UNS K92890 forged forms and size capability
All parts are made to your drawing or dimensional sketch; there is no fixed catalogue. The range below is what Jiangyin Jiangnan Metal Co., Ltd. forges regularly in maraging grades.
| Forged form | Size range | Common uses |
|---|---|---|
| Seamless rolled rings | OD 200-2500 mm, H to 800 mm | Motor cases, spacer rings, flange blanks, gear ring blanks |
| Forged discs and blanks | Ø 150-1500 mm | Rotor discs, blind flanges, tooling plate blanks |
| Forged shafts and spindles | Ø 80-800 mm, L to 8000 mm | Drive and torsion shafts, spindles, stub shafts |
| Round bars and billets | Ø 20-500 mm | Machining stock, fasteners, valve stems, punches |
| Forged flanges | DN 15-1200 | Special high-strength connections to drawing |
| Sleeves, bushings, hollow bars | OD 100-900 mm | Bearing housings, wear sleeves, liners |
| Blocks and rectangles | to 600 × 1200 mm section | Die blocks, tooling, manifolds |
| Tube sheets and nozzles | Ø to 2000 mm | High-pressure vessel components |
| Single-piece weight | 20 kg - 15 000 kg | Heavier pieces quoted case by case |
Source: Jiangyin Jiangnan Metal Co., Ltd. AMS 6512 covers bar and forging stock up to 254 mm (10 in) section; larger sections are supplied to drawing specification. Delivery conditions: as-forged, annealed, maraged, rough machined or finish machined.
Equipment: 1, 3, 5 and 9 tonne open-die forging hammers, a 5000 tonne hydraulic press, and 3 m and 6 m ring rolling mills, with in-house heat treatment, machining and testing.
Where UNS K92890 forgings are used
Maraging 250 is chosen where a part must carry very high stress, survive cyclic loading, and hold its shape through hardening.
Aerospace and space
Solid-propellant rocket motor cases and pressure vessels, where fracture toughness at 255 ksi decides the burst margin.
Aero-engine and airframe
Low-pressure turbine shafts, slat tracks, actuator components and landing-gear parts that need strength without quench distortion.
Ordnance and defence
Ejector systems, missile hardware and high-stress structural forgings, subject to end-use documentation.
Tooling and die making
Die-casting dies, extrusion tooling, plastic injection moulds, punches and cold-forming dies that must be cut soft and hardened without warping.
Power transmission
Torsion and drive shafts, couplings, flexures and gear blanks for compressors, gearboxes and high-speed drives.
Motorsport and high-speed rotating
Transmission shafts, centrifuge and separator rotors, and balancing-critical parts where dimensional stability after hardening is important.
Related forged items we make in this and other grades: forged valve seat rings, forged disks, forged cylinders and general forging products.
Testing, inspection and certification
Every UNS K92890 forging ships with a documentation pack. The content is agreed before production starts.
- Chemical analysis: ladle analysis on every heat, product analysis on the finished forging on request.
- Mechanical testing: tensile, yield, elongation, reduction of area and hardness from integral or separately forged prolongations, in the delivery condition.
- Ultrasonic testing to EN 10228-3, SEP 1921 class C, D or E, ASTM A388, or a customer acceptance class.
- Surface NDT: liquid penetrant to ASTM E165, or magnetic particle where the geometry allows. The alloy is ferromagnetic, so MT is available.
- Grain size and microstructure to ASTM E112.
- Heat-treatment records: furnace time-and-temperature charts for the annealing and ageing charges, traceable to the heat number.
- Dimensional report against the drawing.
- Certification: EN 10204 3.1 as standard, or 3.2 witnessed and counter-signed by TÜV, BV, SGS, Lloyd's Register or your own inspector.
Third-party inspectors and customer QA representatives are welcome at the works. Quality management is to ISO 9001:2015.
How to request a UNS K92890 quotation
Send a drawing or a dimensional sketch to sales@steelforgepieces.com. Quotations are normally returned within one working day when these points are supplied.
- Grade and specification: UNS K92890, Maraging 250, C250 or 18Ni(250), and whether AMS 6512, W.Nr. 1.6359 or your own drawing specification governs.
- Product form: ring, disc, shaft, bar, flange, sleeve, block or custom shape.
- Dimensions: OD, ID and height for rings; diameter and length for bars and shafts; plus an estimated finished weight.
- Delivery condition: annealed for your own machining and ageing, or solution annealed and maraged to final properties; as-forged, rough machined or finish machined.
- Certification: EN 10204 3.1 or 3.2, and which third party if 3.2.
- NDT requirements: ultrasonic acceptance class, PT or MT, and any special acceptance criteria.
- Quantity, destination and required delivery date, so that export documentation can be prepared in parallel.
Lead time for UNS K92890 forgings is normally 30 to 60 days depending on section size, heat-treatment route and machining scope.
Frequently asked questions about UNS K92890
What is UNS K92890?
UNS K92890 is the Unified Numbering System designation for 18 percent nickel maraging steel of the 250 grade, also written Maraging 250, 18Ni(250) and C250. It is a low-carbon iron-nickel-cobalt-molybdenum alloy that is hardened by ageing near 480 °C rather than by quenching. Typical chemistry is 17.0 to 19.0 percent nickel, 7.0 to 8.5 percent cobalt, 4.6 to 5.2 percent molybdenum and 0.30 to 0.50 percent titanium, with carbon held to 0.03 percent maximum and iron as the balance. In the maraged condition it develops at least 1758 MPa (255 ksi) tensile strength and 48 HRC.
Which specifications cover UNS K92890 forgings?
AMS 6512 is the usual controlling specification for UNS K92890 bar and forging stock. The grade is also listed as W.Nr. 1.6359, MIL-S-46850, BS S162, DTD 5212, MSRR 6551, MAT 102 and MIA 101, and as ASTM A538 Grade B for plate, sheet and strip. Vascomax C250 and Udimar 250 are proprietary trade names for the same 250-grade chemistry. Jiangyin Jiangnan Metal Co., Ltd. forges the grade to AMS 6512 chemistry or to a customer drawing specification.
What heat treatment does UNS K92890 need?
Two steps. Solution anneal at about 815 °C (1500 °F) for one hour per 25 mm of section and air cool, which produces soft iron-nickel martensite at roughly 28 to 32 HRC that machines and welds easily. Then marage at about 480 °C (900 °F) for 3 to 6 hours and air cool, which precipitates Ni3Mo and Ni3Ti intermetallics and raises hardness to 48 HRC or more with a tensile strength of at least 1758 MPa. There is no quench, so distortion is very low.
How much does UNS K92890 shrink when it is maraged?
Ageing produces a small, uniform and predictable contraction, typically in the order of 0.04 percent on each dimension, with no quench distortion because the part is air cooled from 480 °C. That is why the grade is machined close to size in the annealed condition and then aged. For tight-tolerance features, allow the contraction on the drawing or finish grind after ageing, and confirm the value on a first-article part.
What is the difference between Maraging 250 (UNS K92890) and Maraging 300 (UNS K93120)?
Maraging 300 carries more cobalt, about 8.5 to 9.5 percent, and more titanium, about 0.55 to 0.80 percent, so it ages to a higher strength: at least 1931 MPa (280 ksi) against 1758 MPa (255 ksi) for the 250 grade. The 250 grade is tougher, more forgiving in thick sections and easier to machine and weld. Choose 250 where fracture toughness and reliability matter, and 300 where the design is strength-limited and the section is small.
Is UNS K92890 corrosion resistant?
No. UNS K92890 contains only residual chromium, up to 0.50 percent, so it is not a stainless steel and it rusts in damp air much like a low-alloy steel. It does resist stress-corrosion cracking better than quenched and tempered steels at the same strength level. Parts in service are normally plated, painted, phosphated or otherwise protected, and any acid pickling or electroplating should be followed by a hydrogen-embrittlement relief bake.
Can UNS K92890 be welded?
Yes, and weldability is one of the reasons the grade is chosen. Carbon is limited to 0.03 percent maximum, so the heat-affected zone does not form hard, crack-sensitive carbides and no preheat is needed. The usual practice is to weld in the annealed condition with matching filler, then age the assembly at 480 °C, or solution anneal and age where the weld region has segregated.
What is the maximum service temperature of UNS K92890?
About 400 °C (750 °F) for load-bearing parts. Because the strengthening precipitates are formed at 480 °C, continuous service close to or above that temperature will over-age the structure, soften the part and reduce strength. UNS K92890 is a high-strength structural steel, not a high-temperature alloy. For hot service, use a nickel-based superalloy such as Inconel 718 or Waspaloy.
When should UNS K92890 be machined, before or after ageing?
Machine in the annealed condition at 28 to 32 HRC, which cuts much like quenched and tempered alloy steel of similar hardness, then age. Because ageing shrinks the part by roughly 0.04 percent with no quench distortion, close-tolerance parts can be finished before hardening. Only finish grinding, honing or lapping is normally done after ageing.
Why is UNS K92890 listed under nickel alloys if it is a steel?
UNS K92890 is an iron-based alloy, so it is properly a steel, but 17 to 19 percent nickel and 7 to 8.5 percent cobalt put it well outside conventional alloy-steel practice, and buyers usually look for it beside the nickel grades. Jiangyin Jiangnan Metal Co., Ltd. lists it in the nickel alloy section for that reason, alongside Monel, Inconel, Incoloy and Hastelloy.
What forged shapes and sizes can be made in UNS K92890?
Jiangyin Jiangnan Metal Co., Ltd. produces UNS K92890 as seamless rolled rings from 200 to 2500 mm outside diameter, forged discs to 1500 mm diameter, shafts and spindles from 80 to 800 mm diameter and up to 8000 mm long, round bars from 20 to 500 mm diameter, plus flanges, sleeves, bushings, hollow bars, blocks and tube sheets, in single-piece weights from 20 kg to 15 000 kg. AMS 6512 covers sections up to 254 mm (10 in); heavier sections are quoted case by case.
Who supplies UNS K92890 open-die forgings 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, forging UNS K92890 (Maraging 250) into rolled rings, discs, shafts, flanges and bars to customer drawing. Enquiries go to sales@steelforgepieces.com or 0086-189-2135-9659. Jiangyin sits in the Yangtze River Delta within about two hours of Shanghai port, which keeps export logistics short for heavy forgings.
What certificates are supplied with UNS K92890 forgings?
EN 10204 3.1 mill test certificates are standard and cover ladle analysis, mechanical test results, heat-treatment charts, NDT reports and dimensional records. EN 10204 3.2 certificates counter-signed by TÜV, BV, SGS or Lloyd's Register are available on request. Ultrasonic testing is reported to EN 10228-3, SEP 1921 or ASTM A388 as specified on the order.
Is there a minimum order quantity for UNS K92890 forgings?
There is no fixed minimum quantity and single prototype pieces are accepted, although price per piece falls with quantity because billet, set-up and furnace charges are shared. Lead time is normally 30 to 60 days depending on section size, heat-treatment route and machining scope.
About the manufacturer
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China. We produce forged rings, seamless rolled rings, discs, shafts, flanges, bars, sleeves and bushings in carbon steel, alloy steel, tool steel, stainless steel, maraging steel and nickel-based superalloys. Work is made to customer drawing and certified to EN 10204 3.1 or 3.2, with raw material, forging, heat treatment, machining, testing and inspection organised on one site.
Company details
- Company
- Jiangyin Jiangnan Metal Co., Ltd.
- Business
- Open-die forging, seamless ring rolling, heat treatment, machining
- Address
- No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China
- Telephone
- 0086-189-2135-9659
- sales@steelforgepieces.com
- Website
- www.steelforgepieces.com
- Quality
- ISO 9001:2015 · EN 10204 3.1 / 3.2 · third-party witnessed testing on request
Data source and citation
The technical data on this page is published by Jiangyin Jiangnan Metal Co., Ltd. and may be quoted, reproduced or cited with attribution. Suggested citation:
Jiangyin Jiangnan Metal Co., Ltd. (2026). UNS K92890 (Maraging 250) Forgings: Technical Datasheet. Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Nickel-Alloy/UNS-K92890.html
Page published by Jiangyin Jiangnan Metal Co., Ltd. Technical data reviewed against AMS 6512 chemistry limits. Last reviewed 28 August 2026 by the technical sales team. Data is offered for engineering guidance; the governing document for any order is the purchase specification and the mill certificate issued with the goods.