Nimonic 90 (also called UNS N07090, 2.4632, NiCr20Co18Ti) is a Ni-Cr-Co precipitation-hardenable superalloy rated for service up to 920°C. It out-performs Nimonic 80A above 750°C and Inconel 718 above 650°C thanks to its 15–21% cobalt addition. Standard heat treatment: 1,080°C × 8h AC + 700°C × 16h AC. Governed by EN 10302:2008; also meets ASTM B637. Applications include gas turbine blades, steam turbine valve spindles, HPHT downhole tools, and hot-working dies. Jiangsu Liangyi manufactures Nimonic 90 forgings up to 30 tons/piece with ISO 9001:2015 certification, EN 10204 3.1/3.2 MTC, and 4–8 week lead time.
1. Alloy Identity — Names, Standards & Codes
Engineers encountering Nimonic 90 for the first time often find it listed under different names in different specification systems. All of the following names refer to the exact same alloy composition, governed by the same standard (EN 10302:2008):
Always specify both the UNS number (N07090) and the EN number (2.4632) in your RFQ. This eliminates designation ambiguity across European, North American, and Asian supply chains. Jiangsu Liangyi material test certificates reference all common designations simultaneously.
2. Chemical Composition (EN 10302:2008)
Nimonic 90 is built on a nickel-chromium base with cobalt as the critical strengthening addition. Titanium and aluminium provide the precipitation-hardening response through the γ′ [Ni₃(Ti,Al)] phase. The full composition per EN 10302:2008 is shown below:
| Element | Min % | Max % | Role in the Alloy |
|---|---|---|---|
| Nickel (Ni) | Balance | — | Matrix base; inherent corrosion and oxidation resistance |
| Chromium (Cr) | 18.0 | 21.0 | Forms Cr₂O₃ protective oxide; oxidation and hot-corrosion resistance |
| Cobalt (Co) | 15.0 | 21.0 | Raises γ′ solvus; slows precipitate coarsening; solid-solution strengthening — the defining addition vs. Nimonic 80A |
| Titanium (Ti) | 2.0 | 3.0 | Primary γ′ [Ni₃Ti] former — essential for elevated-temperature strength |
| Aluminium (Al) | 1.0 | 2.0 | Secondary γ′ former; improves oxidation resistance above 800°C |
| Iron (Fe) | — | 1.5 | Controlled residual (kept low to maintain high-temperature properties) |
| Carbon (C) | — | 0.13 | Forms M₂₃C₆ carbides at grain boundaries; beneficial in controlled quantities |
| Manganese (Mn) | — | 1.0 | Deoxidiser during melting; minor solid-solution effect |
| Silicon (Si) | — | 1.0 | Deoxidiser; minor oxidation resistance benefit |
| Sulphur (S) | — | 0.015 | Controlled impurity — grain-boundary embrittlement risk if above limit |
| Boron (B) | — | 0.008 | Grain-boundary strengthener; improves creep rupture ductility |
| Zirconium (Zr) | — | 0.15 | Grain-boundary oxide former; refines grain boundary microstructure |
Source: EN 10302:2008. Nickel (Ni) is the balance element, typically 54–58% after all alloying additions are accounted for.
Why Cobalt Is the Defining Difference
Unlike Nimonic 80A, which has no intentional cobalt, Nimonic 90 adds 15–21% Co. Cobalt raises the γ′ solvus temperature and dramatically slows the rate at which γ′ precipitates coarsen during high-temperature service. The net result: Nimonic 90 retains meaningful mechanical properties at temperatures 80–100°C higher than Nimonic 80A — a decisive engineering advantage in gas turbine and advanced steam turbine design.
3. Mechanical & Physical Properties
Room-Temperature Properties (Solution + Aged Condition)
| Property | Minimum Value | Standard / Test Condition |
|---|---|---|
| Tensile Strength (Rm) | ≥ 1,220 MPa | EN 10302:2008, aged bar |
| 0.2% Proof Stress (Rp0.2) | ≥ 850 MPa | EN 10302:2008, aged bar |
| Elongation (A) | ≥ 18% | EN ISO 6892-1 |
| Reduction of Area (Z) | ≥ 20% | EN ISO 6892-1 |
| Hardness | 300 – 360 HB | Typical range, aged condition |
| Charpy Impact Energy | ≥ 50 J | EN ISO 148-1, room temperature |
Elevated-Temperature Performance (Indicative Data for Design)
| Temperature | 0.2% Proof Stress | Tensile Strength | 100h Stress-Rupture Strength |
|---|---|---|---|
| 700°C | ~750 MPa | ~900 MPa | ~540 MPa |
| 750°C | ~650 MPa | ~800 MPa | ~380 MPa |
| 800°C | ~520 MPa | ~650 MPa | ~240 MPa |
| 850°C | ~360 MPa | ~480 MPa | ~130 MPa |
| 920°C | ~180 MPa | ~260 MPa | ~50 MPa |
Indicative values for wrought, fully solution-annealed + aged material. Actual test results depend on product form, section size, and heat treatment batch. Always request certified test data from EN 10204 3.1/3.2 MTC for design calculations.
Physical Properties
| Property | Value | Condition / Temperature |
|---|---|---|
| Density | 8.18 g/cm³ | Room temperature (20°C) |
| Melting Range | 1,310 – 1,370°C | Solidus to liquidus |
| Thermal Conductivity | 11.2 W/(m·K) | at 20°C |
| Specific Heat Capacity | 461 J/(kg·K) | at 20°C |
| Thermal Expansion (CTE) | 12.7 × 10⁻⁶ /°C | 20–500°C average |
| Electrical Resistivity | 1.18 µΩ·m | at 20°C |
| Elastic Modulus (E) | ~220 GPa | at 20°C |
📊 Maximum Recommended Service Temperature — Alloy Comparison
4. Heat Treatment Schedule
Nimonic 90 requires a mandatory two-stage heat treatment consisting of a solution anneal followed by an aging treatment. Both stages must be completed correctly — skipping or abbreviating either stage will produce a part that does not meet elevated-temperature property specifications.
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Solution Anneal — 1,080°C × 8 hours, Air Cool (AC)
Dissolves all γ′ precipitates and grain-boundary carbides. Homogenises the matrix composition and recrystallises the forged microstructure. Air cooling (rather than water quenching) is standard and avoids residual stress introduction in thick-section forgings. After this stage only, the part has near-minimum tensile strength and very low stress-rupture life — do not put into service without completing Stage 2.
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Aging Treatment — 700°C × 16 hours, Air Cool (AC)
Precipitates the γ′ phase [Ni₃(Ti,Al)] at the optimal particle size (typically 50–150 nm diameter) and volume fraction (~45–50% Vf) for maximum stress-rupture life and creep resistance. This stage converts a soft, ductile annealed microstructure into a high-strength, creep-resistant component. The 700°C aging temperature is below the γ′ solvus, so precipitates grow without dissolving. Both temperature accuracy (±5°C) and hold time are critical — document with calibrated chart recorders.
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Post-Treatment Verification — Hardness + Full Mechanical Testing
Post-aging hardness should fall in the 300–360 HB range. Each heat-lot undergoes full tensile testing (Rm, Rp0.2, A, Z) and Charpy impact testing. Results are documented on the EN 10204 3.1 or 3.2 material test certificate and accompany every shipment. Jiangsu Liangyi's in-house testing laboratory is equipped with spectroscopic chemical analysers, servo-hydraulic test frames, and calibrated hardness testers traceable to national standards.
Parts supplied in solution-annealed condition only will have near-minimum tensile strength and dramatically reduced stress-rupture life — typically less than 20% of fully-aged performance at 800°C. Always confirm your supplier delivers parts in the fully solution-annealed AND aged condition. If you intend to perform aging yourself, ensure your furnace is calibrated and you have documented temperature uniformity surveys (TUS) per AMS 2750 or equivalent.
5. Forging Process & Available Product Forms
Nimonic 90 is significantly more demanding to forge than stainless steels or low-alloy steels, but is well within the capability of manufacturers with dedicated nickel superalloy experience. The critical process parameters are:
| Parameter | Specification | Engineering Reason |
|---|---|---|
| Forging temperature range | 1,010°C – 1,150°C | Must be above γ′ solvus for workability; must stay below incipient melting temperature to avoid liquation cracking |
| Minimum forge temp (per pass) | 950°C | Below this, strain-induced precipitation hardening increases flow stress rapidly and risks surface or internal cracking |
| Inter-pass reheat | Required for heavy reductions | Temperature drop across thick sections (especially rings > 500 mm OD) must be compensated with reheat soaks |
| Preferred melting route | EAF + VOD + ESR | Electroslag remelting (ESR) removes inclusions and shrinkage porosity, producing a clean, homogeneous billet that passes ASTM A388 UT cleanly |
| Preferred equipment | Hydraulic press (slow strain rate) | Hammers can introduce adiabatic heating and centre-burst; hydraulic presses allow controlled deformation with temperature monitoring |
Available Product Forms at Jiangsu Liangyi
At our 80,000 m² Jiangyin facility, we manufacture the complete range of Nimonic 90 forged parts, all delivered fully heat-treated, NDT inspected, and certified:
Round Bars & Rods
Diameter 20–800 mm, lengths to 6 m. Turbine shafts, valve stems, machined fastener blanks.
Seamless Rolled Rings
OD 200–6,000 mm, up to 30 tons/piece. Turbine discs, casing flanges, seal rings.
Flat Bars & Blocks
Custom cross-sections for tooling blocks, die inserts, structural components.
Discs & Pancakes
Near-net-shape discs minimise machining waste on expensive superalloy stock.
Custom Near-Net Shapes
Complex geometries from customer drawings. No minimum order quantity for prototype development.
6. Alloy Comparison: Nimonic 90 vs. Alternatives
Selecting the right superalloy depends on matching the material's performance window to your actual operating conditions, budget, and fabrication constraints. The table below covers the most commonly compared alternatives:
| Alloy | Max Service Temp | Creep >800°C | Weldability | Relative Cost | Best Fit |
|---|---|---|---|---|---|
| Nimonic 90 (N07090) | 920°C ★ | Excellent | Moderate | High | Turbine blades, discs, valve spindles — 750–920°C service |
| Nimonic 80A (N07080) | 815°C | Good | Moderate | Medium-High | Same component types at lower peak temperatures; better cost |
| Inconel 718 (N07718) | 704°C | Limited | Excellent ★ | Medium | Aerospace structures, O&G, welded assemblies below 700°C |
| Waspaloy (N07001) | 980°C | Superior >870°C | Difficult | Very High | Extreme-stress turbine parts where premium cost is justified |
| Nimonic 105 | 950°C | Excellent | Very Difficult | Very High | Highest-temperature turbine blades; hardest to forge |
Choose Nimonic 90 when your component runs continuously above 750°C and creep life is the primary design criterion. Choose Inconel 718 when excellent weldability matters most and operating temperature stays below 700°C. Choose Waspaloy only when mechanical stress is extreme above 870°C and budget allows for the higher material and fabrication premium. Our metallurgical engineers can advise on the optimal alloy selection for your specific application — contact us with your operating conditions.
7. Industrial Applications
Aerospace & Gas Turbines
Nimonic 90 turbine blades, guide vanes, combustion chamber parts, and turbine discs are used in commercial and military gas turbine engines. Turbine blades manufactured by Jiangsu Liangyi from Nimonic 90 operate reliably at metal temperatures approaching 900°C, withstanding extreme centrifugal forces — exceeding 20,000 g at the blade tip — and thermal cycling fatigue. All forgings are manufactured to AMS material specifications (such as AMS 5829) and supplied with full EN 10204 3.1 mill test certificates. Third-party EN 10204 3.2 inspection by customer-nominated bodies (such as SGS, Bureau Veritas, or TÜV Rheinland) can be arranged upon customer request.
Power Generation — Steam Turbines
Nimonic 90 valve spindles, seats, and discs serve in advanced ultra-supercritical (USC) steam turbines operating at steam temperatures above 600°C and pressures up to 35 MPa. In a documented 600 MW steam turbine upgrade project in Southeast Asia, Nimonic 90 valve spindles demonstrated service life 35% longer than the previous material, reducing planned maintenance downtime by 40% per maintenance cycle. Forged rings are widely used as high-temperature casing flanges and sealing components in both steam and gas turbines.
Oil & Gas — HPHT Applications
Downhole tools, wellhead valve seats, seal rings, and safety-critical fasteners for high-pressure, high-temperature (HPHT) wells require simultaneous resistance to corrosion, mechanical load, and temperatures of 600–650°C. Nimonic 90 components are well-suited to sour gas service environments due to the alloy's inherent corrosion resistance. Chemical composition and mechanical properties are fully traceable via EN 10204 3.1 MTC; customers may request testing to NACE MR0175 corrosion resistance criteria as a supplementary requirement at the time of order.
Hot-Working Tooling & Industrial Furnace Equipment
Die casting inserts, hot-extrusion tooling, forging dies, and furnace fixtures benefit from Nimonic 90's exceptional thermal fatigue resistance. Field data from European and North American metal processing plants shows Nimonic 90 hot-working tooling delivering service life approximately 50% longer than H13 tool steel, significantly reducing tooling change frequency and improving cost-per-part efficiency.
8. Quality Testing & Certification Requirements
Engineers and procurement teams sourcing Nimonic 90 forgings should verify the following testing and documentation package from any supplier:
| Test / Inspection | Standard | Purpose |
|---|---|---|
| Chemical Analysis | EN 10302:2008 / ASTM E1476 | Verify composition within specification limits; confirm alloy identity |
| Ultrasonic Testing (UT) | ASTM A388 / EN 10228-3 | Detect internal defects, porosity, inclusions — mandatory for aerospace & power generation |
| Dye Penetrant Inspection (PT) | EN 10228-2 / ASTM E165 | Surface-breaking defect detection on machined surfaces of non-ferritic alloys |
| Tensile Testing | EN ISO 6892-1 / ASTM E8 | Rm, Rp0.2, elongation, reduction of area vs. specification minimums |
| Hardness Testing | EN ISO 6506 / ASTM E10 | Confirm heat treatment response; verify 300–360 HB range achieved |
| Charpy Impact Testing | EN ISO 148-1 / ASTM E23 | Toughness verification at room temperature (≥ 50 J required) |
| Grain Size Measurement | ASTM E112 / EN ISO 643 | Verify microstructure; grain size directly affects creep life and fatigue properties |
| Material Test Certificate | EN 10204 3.1 or 3.2 | 3.1 = manufacturer certified; 3.2 = independently verified by accredited third party |
Every Nimonic 90 forging shipment from Jiangsu Liangyi includes: EN 10204 3.1 MTC (issued by our own quality department, standard on all orders) · Full chemical analysis report · Mechanical test report (tensile, hardness, Charpy) · Heat treatment temperature charts with calibrated furnace records · UT test report · NDT personnel qualification records · ISPM-15 compliant wooden case packing certificate. Digital copies provided 48 hours before vessel departure. EN 10204 3.2 certificates (issued by an independent third-party inspection body) are available upon customer request and at the customer's nomination — we can facilitate inspection by SGS, Bureau Veritas, TÜV Rheinland, DNV, or other bodies agreed at order placement.
9. How to Source Nimonic 90 Forgings — RFQ Checklist
Providing complete information in your request for quotation allows manufacturers to return an accurate and comparable quotation quickly. Use this checklist:
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Product Form & Dimensions
Specify the required shape (round bar / seamless ring / disc / custom). For bars: diameter and length. For rings: OD, ID, height. For discs: OD and thickness. Approximate piece weight is helpful.
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Material Specification & Delivery Condition
State UNS N07090 or EN 2.4632 (or both). Specify delivery condition: solution + aged (standard) or solution-annealed only if you will age in-house. Indicate if any special chemistry restrictions apply beyond EN 10302.
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Testing & Certification Requirements
State governing standard (EN 10302 or ASTM B637). MTC level: 3.1 or 3.2. NDT method and acceptance level. Third-party inspection witness requirement. Any customer-specific supplementary requirements (e.g., GE, Siemens, Rolls-Royce specifications).
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Quantity, Timeline & Delivery Terms
Number of pieces and total weight. Required delivery date or maximum acceptable lead time. Preferred Incoterms: FOB Shanghai (our default), CIF, or DAP. Destination port or address.
10. Frequently Asked Questions
Yes — completely identical. Nimonic 90, UNS N07090, 2.4632, 2.4969, NiCr20Co18Ti, and Udimet 90 all refer to the same nickel-chromium-cobalt superalloy, governed by EN 10302:2008. The variation in names reflects different designation systems: Nimonic 90 is the historic trade name (Special Metals Corp.), N07090 is the UNS (Unified Numbering System) designation, and 2.4632 is the German/European DIN/EN number. Jiangsu Liangyi's mill certificates reference all common designations, eliminating ambiguity in any supply chain.
The critical difference is cobalt content. Nimonic 80A (UNS N07080) contains no intentional cobalt, while Nimonic 90 adds 15–21% cobalt. This cobalt addition raises the γ′ solvus temperature and dramatically slows the rate at which γ′ precipitates coarsen during high-temperature service. The practical result: Nimonic 90 retains useful mechanical properties at temperatures approximately 80–100°C higher than Nimonic 80A. For components that must operate above 800°C, Nimonic 90 is the correct choice. For service below 800°C where the temperature advantage of cobalt is not needed, Nimonic 80A delivers similar performance at lower material cost.
Nimonic 90 requires a mandatory two-stage heat treatment: (1) Solution anneal at 1,080°C × 8 hours, then air cool — this dissolves γ′ precipitates and homogenises the matrix. (2) Aging treatment at 700°C × 16 hours, then air cool — this precipitates the γ′ phase [Ni₃(Ti,Al)] at the optimal particle size for maximum creep resistance and stress-rupture life. Both stages are mandatory. Parts in solution-annealed-only condition will have dramatically reduced elevated-temperature performance — typically less than 20% of the fully aged stress-rupture strength at 800°C.
Nimonic 90 can be welded but requires careful procedure control. It is susceptible to strain-age cracking (SAC) in the heat-affected zone during post-weld heat treatment. Best practices: use TIG (GTAW) welding; pre-heat to 100–150°C for sections >25 mm thick; use matching or slightly over-alloyed filler wire; and perform post-weld solution anneal + re-age to restore HAZ properties. For assemblies where extensive welding is required, Inconel 718 forgings offer significantly better weldability, though they sacrifice high-temperature capability above 700°C.
Jiangsu Liangyi accepts orders starting from 30 kg per piece — there is no minimum total order weight for initial orders. Standard production lead time is 4–8 weeks from order confirmation. Large-diameter seamless rolled rings (OD > 3,000 mm) or pieces > 15 tons may require 8–12 weeks. We issue free quotations within 24 hours of receiving drawings or specifications. For express prototype requirements, contact our sales team directly to discuss schedule acceleration options.
Jiangsu Liangyi holds ISO 9001:2015 certification as its quality management system credential, and has manufactured Nimonic 90 forgings since 1997. Every forging is supplied with an EN 10204 3.1 material test certificate (MTC) issued by our own quality department as standard. We manufacture to EN 10302:2008 and ASTM B637, and can produce material to AMS 5829 and other aerospace specifications upon request — these are material standards we work to, not certifications we hold. EN 10204 3.2 certificates, issued independently by a customer-nominated third-party inspection body (such as TÜV, DNV, SGS, or Bureau Veritas), are available upon customer request and at the customer's nomination. NDT testing is performed to ASTM A388 (UT) and EN 10228-3 acceptance criteria. All forgings receive 100% dimensional inspection and heat-lot mechanical testing as standard.
Nimonic 90 has excellent oxidation resistance up to approximately 1,000°C in air (above its stress-bearing service limit of 920°C), due to the formation of a stable Cr₂O₃ + Al₂O₃ protective oxide layer. For sulphidation resistance, Nimonic 90 provides moderate protection in low-sulphur environments up to ~700°C. In high-sulphur atmospheres above 700°C, chromium sulphide formation can degrade the protective scale. For aggressive sulphidising service above 700°C, higher-chromium alloys such as Haynes 188 or Haynes 230 are more appropriate. Always review the specific gas chemistry with our engineering team before selecting an alloy for sulphidising environments.
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