Hastelloy X (UNS N06002): High-Temperature Nickel Alloy for Instrumentation Fittings, Valves & Tubing
Hastelloy X is a nickel-chromium-iron-molybdenum (Ni-Cr-Fe-Mo) superalloy strengthened through solid-solution hardening, designated UNS N06002. Engineers prize it for a rare combination: strength at high temperature paired with oxidation resistance that holds up to roughly 2200 °F (1200 °C). Crestflo supplies this grade as instrumentation tube and compression fittings, instrumentation valves, and instrumentation tubing. Every piece carries heat/lot-number traceability. Each is engineered as a drop-in replacement for the major suppliers' offerings, and delivery runs 6-8 weeks, serving customers across the US.
The composition, mechanical, physical and temperature values below reflect standard published data for the alloy, drawn from the applicable ASTM and AMS specifications. Crestflo can customize these to your requirement.
Scope: in this document, Hastelloy X refers specifically to the high-temperature Ni-Cr-Fe-Mo superalloy (UNS N06002) used in fluid-system tube fittings, compression ferrules, instrumentation valves and tubing. It's the heat-resistant X grade, and it isn't the same as the wet or sour-corrosion C-grades (C-276, C-22) or the reducing-acid B-grades (B-2, B-3). Crestflo supplies this alloy only in instrumentation fitting, valve and tubing forms. Mill bar, sheet, plate and pipe aren't part of what's offered.
Request a Hastelloy X Quote · Request a Sample · sales@crestflousa.com · +1 346 594 9005 (Houston, TX)
Hastelloy® is a registered trademark held by Haynes International, Inc. Crestflo has no affiliation with that company, and Haynes International doesn't endorse Crestflo in any way.
Hastelloy X Also Known As: UNS N06002, Alloy X & W.Nr. 2.4665
Drawings, datasheets and purchase orders don't always agree on what to call this material. One might list "Alloy X," another "N06002 alloy," a third "NiCr22Fe18Mo." All three point to the same high-temperature Ni-Cr-Fe-Mo superalloy.
| Designation type | Value |
|---|---|
| Trade / common names | Hastelloy X, Hastelloy Alloy X, Alloy X, HASTELLOY X |
| UNS number | UNS N06002 (N06002) |
| Werkstoff (W.Nr.) | 2.4665 (Werkstoff 2.4665) |
| DIN designation | NiCr22Fe18Mo |
| AMS specifications | AMS 5536 (sheet/plate/strip), AMS 5754 (bar/forgings), AMS 5390 (castings) |
| Equivalent grades / trade names | GH3536 / GH536 (Chinese equivalent), Nicrofer 4722 |
| Alloy family | Nickel-base, solid-solution-strengthened Ni-Cr-Fe-Mo superalloy |
| Spaced / reversed forms | Alloy X nickel, X Hastelloy, N06002 Hastelloy |
UNS N06002 is the US designation. W.Nr. 2.4665, or DIN NiCr22Fe18Mo, is the European one. Both point to the same alloy, so no matter which designation shows up on a part, it's the same Hastelloy X.
Hastelloy X Chemical Composition (Ni-Cr-Fe-Mo, per ASTM/AMS)
Hastelloy X gets its performance from a balanced nickel matrix, with high chromium content for oxidation resistance. Substantial iron and molybdenum add solid-solution strength, and small additions of cobalt and tungsten round out the mix. Its chemistry differs from that of a nickel-base corrosion alloy in one key way: it's tuned for strength and stability at temperature, not for resisting aqueous corrosion.
| Element | wt % (nominal, per applicable ASTM/AMS) |
|---|---|
| Nickel (Ni) | Balance (~47) |
| Chromium (Cr) | 20.5–23.0 |
| Iron (Fe) | 17.0–20.0 |
| Molybdenum (Mo) | 8.0–10.0 |
| Cobalt (Co) | 0.5–2.5 |
| Tungsten (W) | 0.2–1.0 |
| Manganese (Mn) | 1.0 max |
| Silicon (Si) | 1.0 max |
| Carbon (C) | 0.05–0.15 |
| Boron (B) | 0.010 max |
The ranges follow whatever ASTM or AMS product-form spec applies. Crestflo verifies the actual heat chemistry as well; you'll find it on the EN 10204 material test certificate that comes with every order.
Hastelloy X Mechanical Properties (Annealed)
Hastelloy X, in the solution-annealed condition, offers a rare combination: the strength needed for high-temperature service alongside the ductility to form fittings, ferrules and valve components. The figures below are standard published, room-temperature, annealed properties. The alloy's real edge lies elsewhere, though, it holds onto a large fraction of that strength at elevated temperature, thanks to solid-solution strengthening.
| Property | Typical value (annealed, RT) |
|---|---|
| Tensile strength | ~690–785 MPa (100–114 ksi) |
| Yield strength (0.2% offset) | ~310–360 MPa (45–52 ksi) |
| Elongation | ~40–45% |
| Hardness | ~90 HRB |
| Modulus of elasticity | ~205 GPa (~30 × 10⁶ psi) |
The figures shown are typical published values for the annealed condition. Final, certified per-heat properties are stated on the material test certificate supplied with each order, prepared to the applicable standard. That certificate can be customized to your requirements.
Hastelloy X Physical Properties: Density, Melting Point & Magnetic Response
The physical constants below govern weight, thermal behavior and inspection method selection. Hastelloy X is essentially non-magnetic in the annealed condition, which matters where magnetic permeability is a concern.
| Property | Value |
|---|---|
| Density | 8.22 g/cm³ (0.297 lb/in³) |
| Melting range | ~1260–1355 °C (2300–2470 °F) |
| Structure | Face-centered cubic (austenitic nickel matrix) |
| Magnetic response | Essentially non-magnetic (annealed) |
| Modulus of elasticity | ~205 GPa (~30 × 10⁶ psi) at room temperature |
| Thermal conductivity | ~9.1 W/m·K at room temperature (nominal) |
| Mean coefficient of thermal expansion | ~13.9–16.3 µm/m·°C over 20–800 °C (nominal) |
The physical values listed here are the standard published nominal figures for this alloy. Thermal expansion and conductivity aren't constant. Both shift depending on the temperature range, so for design calculations, pull the figures from whichever range actually applies.
Hastelloy X Temperature Capability & High-Temperature Strength
Hastelloy X is, above all, a high-temperature alloy. In oxidizing atmospheres, it holds up under continuous service to roughly 1200 °C (2200 °F), and it keeps useful strength through the combustion-zone temperature band, right where austenitic stainless steels start losing their grip on load. Solid-solution strengthening drives that strength: chromium, iron, molybdenum, cobalt and tungsten, all dissolved into the nickel matrix. Precipitation hardening isn't part of the picture, and that's exactly what keeps the alloy stable and weldable even at temperature. Gas-turbine combustors, transition ducts, industrial-furnace components: these are the parts where Hastelloy has earned its long track record. High-temperature instrumentation lines that need to survive furnace and flare environments count on it too. But maximum service temperature isn't a fixed number. It depends on the atmosphere and the stress involved. The figures given here are standard published limits; actual design ratings get set per the applicable code, and they can be adjusted to fit specific requirements.
Hastelloy X Corrosion & Oxidation Resistance
Hastelloy X earns its keep at high temperature. It grows a chromia scale that shields it from oxidation up to around 1200 °C, and it shrugs off carburizing, nitriding and chlorine-bearing atmospheres better than most heat-resistant alloys manage at similar heat. Stress-corrosion cracking resistance is solid too. None of this concerns wet or aqueous corrosion; it's strictly a high-temperature story.
Hastelloy X isn't the right pick for wet, acidic, or sour service containing H₂S. That job belongs to the C-grades and B-grades. When your application calls for aqueous corrosion resistance or sour service under NACE MR0175 / ISO 15156, rather than protection against high-temperature oxidation, specify:
- Hastelloy C-276: the go-to choice for wet chlorine, hot acids, chlorides and sour service.
- Hastelloy C-22: its higher-chromium companion, suited to strongly oxidising conditions and mixed-acid duty.
- NACE MR0175, sour-service material requirements.
For guidance on choosing an alloy against a specific process, consult the corrosion-by-media × alloy matrix.
Hastelloy X Fabrication: Welding, Machining & Forming
Hastelloy X welds up without much trouble. It takes well to the common gas-shielded processes, provided you use a matching high-nickel filler suited to the grade, and that's part of why it shows up so often in welded ducting and instrumentation assemblies. Like most solid-solution nickel alloys, it work-hardens. Machinists handle that with positive-rake, sharp tooling, rigid setups and plenty of coolant. Formability is another strong point: both hot and cold forming work well for bends and cold-formed parts. Welding consumables and procedures get selected against the applicable code for each joint, and can be tailored to whatever the job needs. At Crestflo, instrumentation forms are built from certified material to the relevant ASTM/AMS specification.
Hastelloy X Product-Form Standards (ASTM B435, B572, B366, B619/B622/B626 & AMS)
A family of ASTM and AMS specifications covers this alloy, organized by product form. Each one defines the grade. What Crestflo actually supplies are the instrumentation forms, fittings, valves, and tubing, made from certified material to those specifications. Not the mill forms themselves.
| Product form | ASTM | AMS |
|---|---|---|
| Sheet, plate & strip | B435 | AMS 5536 |
| Rod & round bar | B572 | AMS 5754 |
| Seamless pipe & tube | B622 | — |
| Welded pipe | B619 | — |
| Welded tube | B626 | — |
| Wrought fittings | B366 | — |
| Castings | — | AMS 5390 |
Values and grades follow the applicable ASTM or AMS specification. Every order ships with EN 10204 material certificates, each one referencing the applicable EN 10204 MTC level.
When to Choose Hastelloy X vs Inconel 625, Inconel 601, Inconel 600 & C-276
Hastelloy X earns its place when oxidation resistance at high temperature is the deciding factor. Below, it stands next to the alloys buyers most often weigh against it. Each one links out to its own material page or a head-to-head comparison, including Hastelloy itself.
| Alloy | Key strength | Choose when | More detail |
|---|---|---|---|
| Hastelloy X (N06002) | High-temperature strength + oxidation resistance to ~1200 °C | Combustion, furnace and high-temperature oxidizing service is the governing requirement | This page |
| Inconel 601 (N06601) | High-temperature oxidation and scaling resistance | Cyclic-oxidation and scaling resistance dominate over peak strength | Inconel 601 |
| Inconel 600 (N06600) | General-purpose Ni-Cr-Fe with oxidation and chloride stress-corrosion resistance | Broad high-temperature and aqueous service is needed without Hastelloy X's peak strength | Inconel 600 |
| Inconel 625 (N06625) | High strength with good aqueous corrosion resistance | Combined elevated-temperature strength and wet-corrosion resistance are needed | Inconel 625 · Hastelloy vs Inconel |
| Hastelloy C-276 (N10276) | Broad wet/reducing + oxidising corrosion resistance; Cl-SCC immunity | The service is aqueous corrosion or sour, not high-temperature | Hastelloy C-276 |
If you're weighing the two head-to-head, start with the Hastelloy vs Inconel guide. Then pick an alloy by service condition to match the material to your actual operating conditions.
Hastelloy X Applications & Industries
Hastelloy X earns its place wherever metal has to hold its strength and resist oxidation in the hottest part of a process. Typical duties include aerospace and gas-turbine combustors and transition ducts, industrial-furnace hardware, and high-temperature petrochemical service. It also shows up in high-temperature instrumentation and sampling lines exposed to furnace, flare and combustion environments. Crestflo supplies the alloy in instrumentation forms for these applications across petrochemical & chemical processing and downstream refining.
Hastelloy X Product Forms from Crestflo: Fittings, Valves & Tubing
Crestflo offers UNS N06002 across three instrumentation product forms, and each one gets its own detail page covering sizes starting at 2 in., pressure ratings, and ordering information. Mill forms like sheet, plate, strip, bar, wire, and coil are the alloy's usual commercial products. Crestflo's US catalog, though, sticks to instrumentation fittings, valves, and tubing. Need something forged or flanged? Those specials are quoted on request.
- Hastelloy X tube & compression fittings, available as single or double ferrule, hardened or non-hardened, in both imperial and metric sizes, with end connections up to 2 in. (50 mm) OD. Buyers also know these as Hastelloy X compression fittings, Alloy X ferrule fittings, or UNS N06002 fittings. Each compression tube fitting is performance-qualified per ASTM F1387.
- Hastelloy X instrumentation valves, needle, ball, check, and 2/3/5-way manifold valves built from high-nickel alloy, ranging from 1/16 in. To 1 in. The pressure-boundary design follows ASME B16.34, and testing follows API seat-leak and shell-test practice.
- Hastelloy X alloy tubing, seamless and welded Alloy X / N06002 instrumentation tubing, offered in imperial and metric OD and wall thickness.
Every Crestflo Hastelloy X part ships with a heat/lot number and an EN 10204 material test certificate. Sizes, ferrule type and thread standard are set to your requirement, check the full range at the tube-fittings hub and the materials hub.
Why Crestflo for Hastelloy X
We Engineer Confidence, and for a high-temperature superalloy like Hastelloy X, that means PMI-verified chemistry, honest sourcing and real interchange, delivered in extractable specs rather than buried inside a PDF. As a US-serving Hastelloy X supplier and manufacturer, we back every part with traceable material and a configured, quoted cost. No online cart guesswork.
- Drop-in interchange for Swagelok®, Parker®, Hoke® and Hy-Lok®: dimensional interchange, with compression fitting ends backed by ASTM F1387 performance qualification (these are interchange/equivalent parts, not "compatible" or "intermix"). Request your Swagelok®/Parker® cross-reference from our engineering team via the cross-reference page.
- Lead time runs 6-8 weeks, against 20+ weeks typical for the majors. Check the lead-time capability page for details.
- Full traceability: heat and lot numbers on every part, EN 10204 MTC 3.1 as standard (3.2 on request), and PMI to confirm the material really is N06002. In-house testing backs it all up.
- Imperial and metric, single and double ferrules (hardened or non-hardened), across all fittings. Valves are qualified to ASME B16.34, with API test practice.
- ISO 9001 / 14001 / 45001 & PED certified, with in-house CNC / VMC / EDM machining, small MOQs, and private-label options.
- The heritage behind the brand: Crestflo is the instrumentation division of a four-decade-old export house recognized by the Government of India, with a proven track record delivering into the Middle East. New manufacturing, deep export pedigree. Read more about Crestflo.
Stock & delivery: standard items ship from ready stock; specials are made to order and take 6-8 weeks. Origin: material is of Indian origin, though US and European melt is available on request. Full traceability comes with it (origin & compliance).
Buyers: Request a Quote or a Sample if you're an end user, EPC, or panel fabricator. Equipment manufacturers and OEMs can talk to an engineer or send us a print. Ready to sell our line? Become a distributor. We serve the petrochemical & chemical and downstream refining industries throughout the US.
Hastelloy X FAQs
What is Hastelloy X?
Hastelloy X, designated UNS N06002, is a nickel-chromium-iron-molybdenum superalloy strengthened through solid-solution hardening. It holds up well under heat, resisting oxidation at temperatures as high as 2200 °F (1200 °C). Engineers rely on this Hastelloy grade for gas-turbine combustors. It also shows up in industrial furnaces and high-temperature instrumentation, where its strength at extreme temperatures matters most.
Is Hastelloy X stainless steel?
No. Hastelloy X is a nickel-base alloy, with nickel making up the balance at roughly 47%. It isn't an iron-base stainless steel. That said, it does contain chromium and iron, and those elements help give Hastelloy its resistance to oxidation at high temperatures.
Is Hastelloy X magnetic?
In the annealed condition, Hastelloy X stays essentially non-magnetic. That comes down to its austenitic, face-centered cubic nickel matrix.
Is Hastelloy X FDA approved?
Whether material suits food or pharmaceutical contact depends on the application and the finish chosen, not on the grade alone. Crestflo provides material certificates and can advise on which standard and finish fit your service. Just specify the requirement on your RFQ.
What is the UNS number for Hastelloy X?
Hastelloy X is registered as UNS N06002. Europe calls it something else: W.Nr. 2.4665, or DIN NiCr22Fe18Mo. It's the same alloy, just relabeled. Other systems list it as GH3536/GH536 and Nicrofer 4722.
What is the maximum service temperature of Hastelloy X?
Hastelloy X holds up under continuous service to roughly 1200 °C (2200 °F) in oxidizing atmospheres. That ceiling shifts depending on atmosphere and stress, though, so check it against the design code that applies to your specific application before relying on it.
Is Hastelloy X good for sour / H₂S service?
No, Hastelloy X is a high-temperature alloy, not the go-to choice for sour service. For NACE MR0175 / ISO 15156 sour service, engineers typically specify Hastelloy C-276 or C-22. Check the Hastelloy C-276 page, and the NACE MR0175 standard has the full requirements.
Hastelloy X vs Inconel 625, which should I use?
Go with Hastelloy X when high-temperature oxidation and combustion strength matter most. Need both strength and resistance to aqueous corrosion? Inconel 625 is the better pick. For the full breakdown, check the Hastelloy vs Inconel guide.
What product forms can I get Hastelloy X in from Crestflo?
Instrumentation tube and compression fittings up to 2" (50 mm) OD, instrumentation valves from 1/16" to 1", and instrumentation tubing, Crestflo offers these in both imperial and metric, complete with heat traceability and EN 10204 material certificates. Everything can be customized to requirement. Crestflo doesn't supply mill bar, sheet, plate or wire.
Do you provide material certificates and heat traceability for Hastelloy X?
Yes. EN 10204 3.1 certificates are standard, with 3.2 available on request. Every part carries a heat/lot number, so full traceability is never in question. PMI confirms the alloy, and testing follows Crestflo's in-house QA regime.
What is the lead time, MOQ and price for Hastelloy X parts?
Pricing runs on quotation only; there's no online cart. Standard items are typically in stock and ready to ship, while specials are made to order, with delivery running 6-8 weeks. Small MOQs are available, along with private-label options. Standard product comes from India. Need US or European melt instead? It's available on request, with full traceability. Submit an RFQ with size, form and rating, and we'll configure a part number and price for you.
Related Alloys & Resources
- Inconel 601, nickel alloy for high-temperature oxidation and scaling resistance.
- Inconel 600, a general-purpose Ni-Cr-Fe alloy chosen for high-temperature service and resistance to chloride stress corrosion cracking.
- Inconel 625, a nickel alloy that holds its strength at high temperatures and resists corrosion well.
- Hastelloy C-276 · Hastelloy C-22, these are the Hastelloy grades built for wet and sour corrosion.
- Hastelloy B-2 · Hastelloy B-3, the Hastelloy grades suited to reducing acids.
- Guides for decision-making: Hastelloy vs Inconel, material selection by service, and the corrosion-alloy matrix.
- For the full range, visit the tube-fittings hub or the materials hub.
Request a Hastelloy X Quote
Send over your form (fittings, valves or tubing), size, end connections and line conditions. From there, the Crestflo Engineering Team sends back a configured part number, ratings and price.
Request a Quote · Request a Sample · Browse the materials hub Reach Crestflo at sales@crestflousa.com or +1 346 594 9005. Based in Houston, TX.
Datasheets and CAD files are available to customers on request, and the Crestflo Engineering Team has reviewed this material. Hastelloy® is a registered trademark of Haynes International, Inc. Crestflo isn't affiliated with, or endorsed by, Haynes International. Swagelok® and Parker® remain trademarks of their respective owners.