⚡ Quick Specs: Incoloy 945X
What Is Incoloy 945X?
Incoloy 945X (UNS N09945 / W.Nr. 2.4698) is an age-hardenable nickel-iron-chromium superalloy developed specifically for demanding oil and gas applications. Unlike solid-solution grades that rely only on chromium and molybdenum for corrosion resistance, 945X derives its exceptional strength from gamma-prime (γ′) and gamma-double-prime (γ″) precipitation formed by niobium, titanium, and aluminum during aging. This enables the alloy to deliver tensile strengths above 1200 MPa together with the toughness and corrosion resistance required for sour-service downhole hardware.
The alloy's high nickel content (45–55%) gives it outstanding resistance to chloride-induced stress corrosion cracking, while the balanced Cr-Mo-Cu system provides broad corrosion resistance in brines, completion fluids, and H₂S/CO₂ environments. As an Incoloy 945X manufacturer and supplier, Hangbo Alloy Group supplies the grade in seamless pipe, bar, forging, and fastener forms with full NACE-compliant mill certification.
Chemical Composition
Nominal composition of Incoloy 945X per UNS N09945. All values in weight percent (wt%).
| Element | Incoloy 945X (wt%) |
|---|---|
| Ni | 45.0 – 55.0 |
| Cr | 19.5 – 23.0 |
| Fe | Balance |
| Mo | 3.0 – 4.0 |
| Nb | 2.5 – 4.5 |
| Cu | 1.5 – 3.0 |
| Ti | 0.5 – 2.5 |
| Al | 0.01 – 0.7 |
| Mn | ≤ 1.0 |
| Si | ≤ 0.5 |
| C | 0.005 – 0.04 |
| P | ≤ 0.03 |
| S | ≤ 0.03 |
The 45–55% nickel level is the key to chloride stress-corrosion-cracking resistance, while 19.5–23% chromium provides passivity in oxidizing oilfield fluids. Molybdenum and copper extend resistance to reducing acids and localized corrosion, and the Nb-Ti-Al combination enables age hardening to yield strengths approaching 1100 MPa.
Physical Properties
| Property | Value |
|---|---|
| Density | 8.2 g/cm³ (0.296 lb/in³) |
| Melting Range | 1270 – 1377 °C (2317 – 2510 °F) |
| Specific Heat (room temp) | ~ 440 J/kg·K |
| Thermal Conductivity (23 °C) | ~ 10.9 W/m·K |
| Electrical Resistivity (room temp) | ~ 1.15 µΩ·m |
| Young's Modulus (room temp) | ~ 200 GPa |
| Mean CTE (20–93 °C) | ~ 14.2 × 10⁻⁶ /K |
Mechanical Properties
Typical room-temperature tensile properties after solution anneal and age. Values vary with section size and heat treatment condition.
| Property | Typical Range |
|---|---|
| Tensile Strength (Rm) | 1200 – 1310 MPa (174 – 190 ksi) |
| Yield Strength (Rp0.2) | 990 – 1135 MPa (144 – 165 ksi) |
| Elongation (A%) | 20 – 30% |
| Hardness | 38 – 42 HRC |
| Charpy V-Notch Impact | 88 – 140 J |
Independent test data on solution-treated and aged bars show that Incoloy 945X maintains tensile strength above 1200 MPa even in heavy sections up to 305 mm diameter, with yield strength consistently above 990 MPa and elongation around 27–30%. This combination of high strength and excellent toughness is the reason the grade is approved for critical sour-service components.
High-Temperature & Sour-Service Performance
- Sulfide stress cracking: Approved under NACE MR0175/ISO 15156-3 up to severe sour-service levels including Level VI-450°F and Level VII, making it suitable for high-H₂S downhole environments.
- Chloride stress corrosion cracking: High nickel content provides excellent resistance to chloride-induced SCC, outperforming many 300-series stainless steels and lower-nickel alloys in hot brines.
- Pitting and crevice corrosion: Cr-Mo-Cu system gives useful resistance to localized attack in seawater and completion fluids.
- Maximum NACE temperature: Qualified for sour service up to approximately 232 °C (450 °F), covering most deep, hot oil and gas well conditions.
- Thermal stability: Properly heat-treated material retains strength and toughness after long-term exposure to oilfield temperatures.
Corrosion Resistance
Incoloy 945X offers a corrosion portfolio specifically tuned for oilfield sour service:
- Sour gas (H₂S): Exceptional resistance to sulfide stress cracking and stress corrosion cracking in hydrogen sulfide-bearing environments, validated by NACE testing.
- Chloride brines: High nickel content resists chloride-induced stress corrosion cracking at temperatures well above those tolerated by duplex and austenitic stainless steels.
- CO₂ corrosion: Good general corrosion resistance in carbon dioxide-containing production fluids.
- General oilfield fluids: Performs well in completion brines, packer fluids, and produced water containing chlorides and hydrocarbons.
Applications
Incoloy 945X is specified wherever high strength, sour-service resistance, and reliable downhole performance must coexist. Typical uses include:
| Application Area | Typical Components & Notes |
|---|---|
| Downhole Tubulars | Production tubing, casing, liners, and couplings for sour oil and gas wells |
| Wellhead & Christmas Tree | Valves, connectors, hubs, and flanges requiring NACE hardness compliance |
| Subsea Equipment | Manifolds, jumpers, flowlines, and subsea trees exposed to chlorides and H₂S |
| Completion Hardware | Packers, setting tools, landing nipples, and tubing hangers |
| Fasteners & Bolting | High-strength sour-service bolts, studs, and nuts for BOPs and wellheads |
| Surface Equipment | Pump shafts, seals, valves, and pressure-containing components |
Available Product Forms
| Product Form | Typical Dimensions |
|---|---|
| Seamless Pipe & Tube (ASTM B983) | OD up to 14 in (355 mm), various wall thicknesses |
| Bar & Rod | φ 6 – φ 305 mm, hot-rolled, forged, or cold-drawn |
| Forgings & Rings (ASTM B1007) | Wellhead flanges, hangers, and valve bodies up to 2000 mm OD |
| Fasteners | Studs, bolts, nuts, and washers per API 6A and NACE requirements |
| Wire & Welding Consumables | Matching nickel-base filler metals for GTAW/GMAW repair |
Heat Treatment
| Step | Temperature | Cooling | Purpose |
|---|---|---|---|
| Solution Anneal | 1010 – 1066 °C (1850 – 1950 °F) | Water quench | Dissolve precipitates; soften for forming and machining |
| Aging — First Stage | 704 – 732 °C (1300 – 1350 °F) | Hold 6–8 h | Nucleate γ′ and γ″ strengthening phases |
| Controlled Cool | 26 – 56 °C/h to 607 – 635 °C | Furnace cool | Optimize precipitate size and distribution |
| Aging — Second Stage | 607 – 635 °C (1125 – 1175 °F) | Air cool | Maximize strength and sour-service toughness |
Parts are typically machined in the annealed condition and aged as a final step. Welded fabrications require solution annealing after welding, followed by the full aging cycle, to restore uniform mechanical properties and corrosion resistance.
Related Standards & Specifications
| Standard | Product Scope |
|---|---|
| UNS | N09945 |
| DIN / W.Nr. | 2.4698 |
| ASTM B983 | Seamless pipe and tube |
| ASTM B1007 | Bars, forgings, and parts |
| NACE MR0175 / ISO 15156-3 | Sour-service qualification up to Level VI-450°F and Level VII |
| API 6A | Wellhead and Christmas tree equipment |
Frequently Asked Questions (FAQ)
1. What is Incoloy 945X?
Incoloy 945X (UNS N09945 / W.Nr. 2.4698) is an age-hardenable nickel-iron-chromium superalloy strengthened by niobium, titanium, and aluminum additions. It combines high tensile strength above 1200 MPa with excellent resistance to chloride-induced stress corrosion cracking and sulfide stress cracking in sour oil and gas environments. The alloy is widely used for downhole tubulars, wellhead components, valves, packers, hangers, and subsea equipment.
2. What is the chemical composition of Incoloy 945X?
Nominal Incoloy 945X composition (wt%): Ni 45.0–55.0, Cr 19.5–23.0, Fe balance, Mo 3.0–4.0, Nb 2.5–4.5, Cu 1.5–3.0, Ti 0.5–2.5, Al 0.01–0.7, Mn ≤1.0, Si ≤0.5, C 0.005–0.04, P ≤0.03, S ≤0.03. The high nickel content provides resistance to chloride stress corrosion cracking, while niobium, titanium, and aluminum form gamma-prime and gamma-double-prime strengthening phases during aging.
3. What is the density and melting range of Incoloy 945X?
Incoloy 945X has a density of approximately 8.2 g/cm³ (0.296 lb/in³) and a melting range of about 1270–1377 °C (2317–2510 °F). These values are similar to other high-nickel Incoloy grades, giving a favorable strength-to-weight ratio for heavy-section downhole components.
4. What are the mechanical properties of Incoloy 945X?
Typical room-temperature properties after solution annealing and aging: tensile strength 1200–1310 MPa (174–190 ksi), 0.2% yield strength 990–1135 MPa (144–165 ksi), elongation 20–30%, hardness 38–42 HRC. Actual values depend on section size and heat treatment; smaller diameters generally reach the upper end of the range, while large forgings and bars remain above 1200 MPa tensile strength.
5. How does Incoloy 945X achieve its high strength?
Incoloy 945X is strengthened by a dual precipitation reaction during aging. Niobium, titanium, and aluminum combine with nickel to form gamma-prime (Ni₃(Al,Ti,Nb)) and gamma-double-prime (Ni₃Nb) phases. These coherent precipitates pin dislocations and raise yield strength to approximately 1000 MPa while preserving adequate ductility and toughness for sour-service qualification.
6. What is the maximum service temperature of Incoloy 945X?
Incoloy 945X is optimized for ambient to moderately elevated service temperatures in oil and gas applications, typically up to about 232 °C (450 °F) under NACE MR0175/ISO 15156-3 sour-service limits. Its strength and corrosion resistance make it suitable for deep, hot, sour wells, but for sustained temperatures above 450 °C, dedicated high-temperature superalloys such as Inconel 718 or Waspaloy are usually preferred.
7. What is the corrosion resistance of Incoloy 945X?
Incoloy 945X offers excellent resistance to chloride-induced stress corrosion cracking because of its high nickel content. It also resists sulfide stress cracking in H₂S-bearing sour gas, pitting and crevice corrosion in chloride environments, and general corrosion in oilfield brines and completion fluids. The alloy meets NACE MR0175/ISO 15156-3 requirements up to severe sour-service levels including Level VI-450°F and Level VII.
8. Can Incoloy 945X be welded and machined?
Incoloy 945X can be welded using GTAW, GMAW, and SMAW processes with matching or nickel-base filler metals. Controlled heat input and interpass temperatures are essential to avoid strain-age cracking and to preserve corrosion resistance. In the annealed condition the alloy machines with conventional nickel-alloy practices: rigid setups, sharp carbide or ceramic inserts, positive feeds, and adequate coolant. Aging is normally performed after final machining or welding.
9. What heat treatment is used for Incoloy 945X?
Standard heat treatment: solution anneal at 1010–1066 °C (1850–1950 °F) for 0.5–4 hours, followed by water quenching; then age at 704–732 °C (1300–1350 °F) for 6–8 hours, furnace cool at 26–56 °C/h to 607–635 °C (1125–1175 °F), hold 6–8 hours, and air cool. The two-step aging develops the optimum gamma-prime/gamma-double-prime structure for peak strength and sour-service toughness.
10. What standards apply to Incoloy 945X?
Incoloy 945X is covered by UNS N09945, ASTM B983 (seamless tubing and pipe), ASTM B1007 (bars, forgings, and parts), NACE MR0175/ISO 15156-3 for sour service, and API 6A for wellhead and Christmas tree equipment. DIN/W.Nr. designation is 2.4698. Material is supplied with full mill test certificates including chemical, mechanical, and NACE hardness reports.
11. What are the typical applications of Incoloy 945X?
Primary applications include: (1) Downhole tubing, casing, and liners for sour oil and gas wells; (2) Wellhead and Christmas tree components including valves and connectors; (3) Subsea manifolds, jumpers, and flowlines; (4) Packers, setting tools, and landing nipples; (5) Tubing hangers and liner hangers; (6) High-strength fasteners and bolting for sour service; (7) Pump shafts, seals, and other surface equipment exposed to chlorides and H₂S.
12. What is the difference between Incoloy 945 and Incoloy 945X?
Incoloy 945 and 945X are closely related age-hardenable Ni-Fe-Cr alloys developed for oil and gas sour service. Both share the same UNS N09945 designation in many references and offer very similar chemistry, mechanical properties, and corrosion resistance. The 'X' variant is typically positioned as the higher-strength, more optimized version for the most severe sour-service conditions, including deeper, hotter, and more H₂S-rich wells. For procurement, buyers should specify mechanical property grades such as 140 ksi, 150 ksi, or 160 ksi yield strength.
Need Incoloy 945X for Downhole, Wellhead, or Sour-Service Components?
Hangbo Alloy Group is a trusted global manufacturer and supplier of Incoloy 945X (UNS N09945 / 2.4698) in seamless pipe, bar, forging, and fastener forms. Mill test certificates to EN 10204 3.1, NACE hardness reports, full traceability, and competitive pricing on every order.