Inconel X-750 plate is a precipitation-hardenable nickel-chromium superalloy (UNS N07750, W. Nr. 2.4669) engineered for long-term strength, creep resistance and oxidation stability in service up to roughly 700°C / 1300°F (useful strength can persist to higher short-term temperatures). For designers and buyers who need spring performance, high relaxation resistance, or structural parts for gas turbines, rocket hardware, nuclear components and high-temperature tooling, X-750 plate offers a dependable balance of mechanical performance and corrosion resistance — provided the correct heat treatment and finishing are applied.

What is Inconel X-750?

Inconel X-750 is a nickel-chromium base superalloy rendered precipitation-hardenable by additions of aluminum and titanium (and controlled columbium/niobium). It was developed in the mid-20th century to provide higher strength and creep resistance than simple nickel-chromium alloys, while retaining oxidation and corrosion resistance at elevated temperatures. The alloy is marketed under the Inconel trade name (a registered family of nickel alloys) and is widely used in aerospace, power generation, chemical processing, and nuclear sectors. UNS designation: N07750; European Werkstoff number: 2.4669.

Chemical composition

Below is a practical composition table assembled from standard datasheets and AMS/industry references. Values shown are typical permitted ranges for wrought plate/sheet/strip forms; final shop certificates should be checked for each lot.

(These ranges follow published manufacturer data and SAE/AMS technical definitions for X-750 family material forms.)

Mechanical properties and heat-treat response

Because X-750 is precipitation hardened, properties depend strongly on prior forging/rolling, solution treatment and age-hardening cycles. Below are representative mechanical properties for plate in typical conditions (values for design should be taken from the manufacturer’s mill test certificate and AMS/ASTM spec):

Creep strength and relaxation resistance are the alloy’s distinguishing attributes; designers rely on the controlled age hardening schedule to achieve long-term loads at elevated temperature. For precise design allowables consult AMS tables and Special Metals datasheets.

Standards & specifications

Inconel X-750 plate and strip are produced to several aerospace and industry specifications. When buying plate, request the correct spec and certificate type (3.1/3.2 etc.):

• UNS N07750 / W. Nr. 2.4669 (material designations).

• Common AMS/SAE specs that govern forms and processes: AMS 5542 / AMS 5598 / AMS 5667 / AMS 5670 / AMS 5671 / AMS 5698 / AMS 5699 (different AMS cover sheet, strip, plate, wire, and tempers — consult the exact AMS for plate/strip).

• Applicable ASTM numbers are less common for proprietary trade names; in procurement the buyer typically uses UNS and AMS references for aerospace/material-critical work.

What to request from supplier: mill heat number, chemical analysis, mechanical test data (tensile), hardness, grain size where applicable, and traceability (chain of custody). For aerospace/nuclear projects insist on AMS certification and full traceability.

Plate production forms, typical sizes and tolerances

Producers manufacture X-750 plate by vacuum induction melting or consumable-electrode remelting processes to reduce segregation, followed by hot rolling and solution treatment. Typical offerings from mills and distributors:

• Thickness: from thin shim/strip (<1 mm) up to plate (commonly 0.5 mm – 100 mm depending on mill capacity; practical limits depend on mill size).

• Widths & lengths: to buyer spec; width limited by mill rolling stand.

• Surface finish: mill (cold rolled), ground, or annealed finish as required.

• Delivery conditions: annealed/solution treated plus aged, or solution treated only (final age hardening is often done by fabricator if parts require forming).

Ask the mill for finish condition because forming/welding sequences depend on whether material is supplied in the annealed state or age-hardened.

What is Inconel X750 used for?

X-750 plate is selected where a combination of high temperature strength, low relaxation (springs, bolts), and oxidation resistance is needed. Representative applications:

• Gas turbine components: blades, seals and structural parts where long-term creep matters.

• Rocket engine hardware: thrust chamber parts, cooled liners, and high-temp fasteners.

• High-temperature tooling: heat-treat fixtures, forming tools, extrusion dies.

• Springs, clips and retention devices: plate fabricated into spring elements for elevated temperature springs where relaxation resistance is crucial.

• Nuclear and chemical processing: selected for components where stability at elevated temperatures and in oxidizing environments is required.

Designers choose X-750 when loads at 500–700°C mean ordinary stainless steels or lower-grade nickel alloys would creep or relax unacceptably.

Fabrication, machining and welding notes

• Machining: X-750 work hardens; machine in soft (solution treated) condition where feasible. Use rigid setups, sharp carbide tools, modest continuous cuts and flood coolant. For final passes consider minimal cuts after aging.

• Forming: cold forming possible but plan intermediate anneals; heavy deformation requires solution treatment and controlled aging to restore properties.

• Welding: gamma-prime precipitation-strengthened superalloys (X-750 family) are more challenging to weld than some other nickel alloys (718 is more weldable). Welding can cause heat-affected zone defects and require specific filler metals and post-weld heat treatment. For critical components follow AMS welding guidance and perform qualification tests.

• Heat treatment (plate): solution treat (typical high temp soak), water cool, then age at controlled temperatures (examples: 1300°F / 704°C x several hours — actual cycles vary by AMS/mill). Correct aging yields the gamma-prime precipitates that drive strength. Consult the AMS/producer heat-treat charts for exact parameters.

Corrosion behaviour & environment selection

X-750 has good resistance to oxidation and many oxidizing atmospheres thanks to chromium content, but it is not immune to aggressive halide or highly reducing acid environments. For sour gas (H₂S) or chloride stress-corrosion scenarios, run dedicated materials compatibility tests; some production grades meet NACE/ISO15156 guidance but specifics depend on heat and finishing. For steam, air, and many oxidizing environments at high temperature X-750 performs well.

Equivalents and comparisons

• Material equivalence: the correct designation is UNS N07750 / W. Nr. 2.4669. There is no single “drop-in” exact chemical twin outside the branded Inconel family; some mills produce equivalent compositions under generic names (e.g., “Nickel Alloy X-750 / N07750”). Verify composition and AMS compliance rather than relying on trade names.

• Versus Inconel 718: 718 has higher strength in many temp ranges and better weldability; X-750 excels in relaxation resistance and simple spring/fastener use where long-term creep matters. Do not substitute without re-qualifying designs — the microstructural strengthening mechanisms differ (718: γ″ + γ′; X-750: γ′ precipitation with Nb/Cb interactions).

• Versus 625: 625 is a solid-solution strengthened alloy with excellent corrosion resistance and good strength but it lacks the same high-temp creep/relaxation resistance that X-750 provides. Choose 625 for corrosion priority, X-750 for high-temp creep strength.

2025 Price comparison (USA / Europe / China)

Important: superalloy prices change quickly with raw-material markets, melting method, certification, and order quantity. The table below provides typical market ranges observed in trade sources and distributor snapshots during 2025 — use only as a budgeting guide and obtain firm quotations for procurement decisions.

How price varies: cert level (AMS full qualification), melting method (VIM/ESR/VAR vs basic VIM), lot size, delivery time, and form (plate vs wire) are the main drivers. For critical parts insist on AMS-grade material even if unit price is higher — qualification and lifetime cost justify the premium.

Purchasing advice

Buying high-temperature nickel alloys requires careful documentation:

• Ask for: Mill Heat Number, Chemical Analysis, Mechanical Test Report (tensile), Hardness, NDT if required, and Certificate Type (EN10204 3.1/3.2 or equivalent). For aerospace use AMS certificates and lot test reports.

• Quantity & MOQ: Chinese mills offer lower MOQ and competitive per-kg pricing for non-aerospace orders; certified AMS material usually requires larger minimums and longer lead times.

• Inspection: if brittle or segregation concerns matter, request remelt processes (VAR/ESR) and additional metallurgy tests (grain size, inclusion rating).

• MWAlloys offering: MWAlloys operates as a China-based mill/distributor focusing on nickel and high-temperature alloys. Our standard service for X-750 plate: 100% factory price (mill direct), rapid stock delivery on common thicknesses, flexible MOQ for industrial clients, and AMS/third-party testing on request. Contact MWAlloys with specifications (UNS N07750, thickness, finish, required AMS/ASTM spec) for a formal quotation and shipping lead time.

FAQs

1. Is Inconel X-750 weldable?
Weldability is moderate to challenging: X-750 is a gamma-prime precipitation-hardened alloy — welding can create HAZ issues and loss of properties if not followed by appropriate post-weld heat treatment. For high-criticality components, select filler metals and qualified procedures; or use alloys with better weldability (e.g., 718) when welding is frequent.

2. What is the standard UNS and W.Nr for X-750?
UNS N07750, W. Nr. 2.4669. Always quote these designations in procurement.

3. What service temperature can I expect?
Useful strength up to about 700°C / 1290°F, with useful oxidation resistance to higher temperatures under limited exposures. Creep properties degrade as temperature increases; specify expected loads and temperatures to get correct tempering advice.

4. How does plate differ from wire/foil in specs?
Forms have separate AMS/ASTM spec numbers and different permitted processing routes. Plate suppliers follow AMS/SAE plate/strip specs; wire has distinct AMS numbers (e.g., AMS 5699 for spring wire). Always match the spec to the form.

5. Are there cheaper substitutes?
For moderate temperatures, some stainless steels or Incoloy grades may be less costly, but they will usually lack the same combination of creep and relaxation resistance. Substitution requires engineering validation.

6. Is X-750 suitable for nuclear environments?
X-750 has been used in nuclear components, but selection depends on neutron exposure, corrosion environment, and regulatory qualification; consult nuclear materials specialists. Some heats may be subject to special acceptance criteria.

7. What certifications should I request?
At minimum: chemical analysis, tensile test report, hardness, heat number, and EN 10204 3.1 or 3.2 for aerospace/nuclear. For aerospace insist on AMS traceability and mill/process certifications.

8. Can X-750 be used in marine chloride environments?
It resists oxidation well, but chloride stress corrosion and crevice corrosion risks exist for many nickel alloys; compatibility must be evaluated with testing and selection of surface finishes/processing.

9. How does aging/heat treatment affect properties?
Aging produces γ′ precipitates (Ni₃(Al,Ti)) that harden the alloy. Controlled solution + aging cycles determine final tensile, creep and relaxation resistance. Incorrect cycles reduce long-term performance.

10. How fast can I get material from MWAlloys?
For stock items MWAlloys offers fast warehouse dispatch (typical stock lead times depend on thickness and finish), while AMS remelted or special cert lots require longer mill lead times. Contact MWAlloys with part specs for a same-day quote and firm lead-time.

Technical cautions & best practices

• Always validate material with mill certificate and independent acceptance tests when component safety matters.

• When replacing alloys in existing designs, run mechanical and environmental requalification.

• For high cycle fatigue at elevated temperature, consult creep-fatigue interaction charts and perform component testing where feasible.

• For welded assemblies, plan pre-qualification and post-weld heat treatment steps consistent with AMS and company procedure.

Authoritative references

• INCONEL® alloy X-750 — Special Metals Corporation (technical bulletin, datasheet PDF)
• ASM / Alloy Digest — INCONEL® ALLOY X-750 (technical digest)
• MatWeb / ASM — Material data sheet: Inconel X-750 (UNS N07750)