Inconel X-750 fasteners are precision-engineered joining components made from a precipitation-hardened nickel-chromium superalloy (UNS N07750 / WNR 2.4669), delivering an outstanding balance of tensile strength, oxidation resistance, and creep resistance up to 816°C (1,500°F). Unlike standard stainless or carbon steel bolting, Inconel X-750 bolts, nuts, screws, and threaded rods retain their mechanical integrity and clamping force at elevated temperatures, resisting relaxation even under sustained thermal cycling — making them the preferred choice for aerospace, nuclear, marine, and petrochemical applications where fastener failure is not an option.
Unifit Fastener is an ISO 9001:2015-certified manufacturer, stockist, and global exporter of ASTM B637 Inconel X-750 fasteners, available in metric sizes M1.2 to M160 and imperial sizes from 3/16" to 2". Every batch ships with EN 10204 3.1 material test certificates and full raw-material-to-finished-fastener traceability. Our technical team can help you confirm the correct grade, heat-treatment condition, and custom-machined specification for your application — request a free quote today.
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Inconel X-750 Fasteners Specifications
Inconel X-750 (UNS N07750, WNR 2.4669) fasteners manufactured by Unifit Fastener are produced to ASTM B637 / ASME SB637, in both metric and imperial sizing. The specification table below summarizes material grade, applicable standards, size range, and available product forms — also known by the trade names Pyromet X-750, Haynes X-750, and Nickelvac X-750.
| Specification Category |
Alloy X750 Fasteners Details |
| Material Grade | Inconel® Alloy X-750 / UNS N07750 / WNR 2.4669 |
| Applicable Standards | ASTM B637, ASME SB637 |
| Trade Names | Pyromet® X-750, Haynes® X-750, Nickelvac® X-750 |
| Metric Sizes | M3 to M56 |
| Imperial Sizes | 3/16" to 2" |
| Length Range | 3 mm to 200 mm |
| Density | 8.28 g/cm³ |
| Melting Range | 1393°C – 1427°C |
| Maximum Service Temperature | Up to 816°C (1500°F) |
| Product Forms | Hex Bolts, Heavy Hex Bolts, Nuts, Screws, Stud Bolts, Threaded Rods, Washers |
| Head Styles | Hex Head, Square Head, T-Head, Hex Flange, Round Head, Flat Head |
| Drive Types | Torx, Cross Recess, Slot Drive, Hex Socket |
| Thread Configuration | Right-Hand Thread, Left-Hand Thread, Double-End Thread |
| Thread Series | Metric, UNC, UNF, BSW, BSF |
| Thread Pitch Options | Coarse Thread and Fine Thread |
| Point Styles | Cone Point, Cup Point, Half Dog Point, Full Dog Point, Gimlet Point, Chamfer End |
| Neck Types | Square Neck, Hex Neck, Knurled Neck, Oval Neck |
| Manufacturing Process | CNC Machining, Hot Forging, Cold Forging, Precision Thread Rolling |
| Surface Finishes | Self Colour, Black Oxide, Bright Zinc Plated (BZP), Hot-Dip Galvanized (HDG), Nickel Plated, Zinc-Nickel Coated |
| Special Coatings | Teflon Coating, Dacromet Coating, Chrome Plating, Anodized Finish |
| Testing Methods | PMI Testing, Mechanical Testing, Hardness Testing, Spectro Analysis, Pitting Resistance Testing, Flattening Test |
| Key Advantages | High Tensile Strength, Excellent Creep Resistance, Superior Oxidation Resistance, Excellent High-Temperature Performance |
| Industrial Applications | Aerospace Components, Gas Turbines, Power Generation, Food Processing Equipment, Pharmaceutical Plants, Petrochemical Industry |
| Export Markets | Oman, Qatar, UAE, Lebanon, Turkey, Malaysia and Worldwide |
Types of Inconel X-750 Fasteners
Unifit Fastener manufactures and stocks the full range of Inconel X-750 fastener types below, all traceable to ASTM B637 / UNS N07750 with EN 10204 3.1 material certification.
- Alloy X-750 Bolts in Stock - Eye bolts, flange bolts, and hanger bolts for high-temperature bolted joints requiring sustained clamping load.
- 2.4669 Inconel X-750 Nuts in Stock - Cap, hex, acorn, castle, slotted, and coupling nut styles engineered to match bolt clamping performance across the full service temperature range.
- Inconel Alloy X-750 Washers in Stock - Flat, fender, square plain, spring lock, and structural washers for load distribution and vibration resistance in high-temperature assemblies.
- Nickel Alloy X-750 Screws in Stock - Eye screws, hex lag screws, machine screws, socket cap screws, pan head screws, and self-drilling screws for precision fastening in aerospace and turbine applications.
- Inconel X-750 Stud Bolts in Stock - Fully threaded, double-end, tap-end, flange stud bolts, and threaded rods for flanged and pressure-retaining joints
Alloy X750 Bolts in Stock
2.4669 Inconel X750 Nuts in Stock
Inconel Alloy X750 Washers in Stock
- Nickel X750 Flat Washers
- DIN 2.4669 Fender Washers
- UNS N07750 Square Washers
- ASME B18.22.1 Plain Washers
- Inconel X750 Spring Lock Washers
- Alloy X750 Structural Washers
Nickel Alloy X750 Screws in Stock
- X750 Inconel Eye Screws
- ASME SB 166 Hex Lag Screws
- 2.4669 Inconel X750 Machine Screws
- Inconel X750 Socket Head Cap Screws
- UNS N07750 Pan Head Screws
- Alloy X750 Self-Drilling Screws
Inconel X-750 Stud Bolts in Stock
- ASME B16.5 Fully Threaded Stud Bolts
- Inconel X750 Double-End Stud Bolts
- UNS N07750 Tap-End Stud Bolts
- 2.4669 Alloy X750 Flange Stud Bolts
- Inconel X750 B7 Threaded Rods
Inconel X-750 Chemical Composition (ASTM B637 / UNS N07750)
Inconel X-750's precipitation-hardening response depends on tightly controlled titanium, aluminum, and niobium+tantalum content alongside its high nickel-chromium base. The chemical composition table below is controlled to ASTM B637 requirements to ensure consistent mechanical performance across all heat treatment conditions.
| Ni | Cr | Fe | Ti | Al | Nb+Ta | Mn | Si | Cu | C | S | Co |
| ≥70 | 14–17 | 5–9 | 2.25–2.75 | 0.40–1.0 | 0.70–1.20 | ≤1.0 | ≤0.50 | ≤0.50 | ≤0.08 | ≤0.01 | ≤1.0 |
All percentages shown as maximum (max) or ranges where applicable. Nickel content includes cobalt. Nb+Ta (Niobium + Tantalum) content ranges 0.70–1.20%.
Additional composition details per Dalloyed source: Silicon (Si) = 0.5% max | Aluminum (Al) = 0.4–1.0% | Carbon (C) = 0.08% max | Iron (Fe) = 5–9%.
Inconel X-750 Mechanical Properties (Tensile & Hardness)
Inconel X-750's mechanical properties vary significantly by heat treatment condition. The table below breaks out tensile strength, yield strength, elongation, and hardness across the three standard ASTM B637 UNS N07750 heat treatment types, so you can specify the exact condition your application requires.
| UNS / Condition | Heat Treatment | Tensile Strength | Yield Strength (0.2%) | Elongation / Hardness |
| ASTM B637 UNS N07750 Type 1 | Solution + Stabilize + Precip. Harden | 965 MPa (140 ksi) | 620 MPa (90 ksi) | 8% / 262–302 HB |
| ASTM B637 UNS N07750 Type 2 | 1800°F Solution + Precip. Harden | 1170 MPa (170 ksi) | 790 MPa (115 ksi) | 18% / 302–363 HB |
| ASTM B637 UNS N07750 Type 3 | 2000°F Anneal + Precip. Harden | 1103–1276 MPa max | 689–896 MPa max | 20% / 267–363 HB |
Physical & Thermal Properties
Beyond mechanical strength, Inconel X-750's physical and thermal properties determine its suitability for high-temperature service. These figures apply across the standard heat-treated condition range.
| Property | Value | Notes |
| Density | 8.28 g/cm³ (0.299 lb/in³) | |
| Melting Range | 1393–1427°C (2540–2600°F) | |
| Melting Point (Solidus/Liquidus) | 1390°C / 1430°C | |
| Heat Capacity | 0.431 J/g·°C | |
| Thermal Conductivity (at 70°F) | 83 Btu/hr·sq ft/°F | Increases to 154 at 1400°F |
| Electrical Resistivity (at 70°F) | 731 ohm·circ mil/ft | |
| Temperature Range | Up to 816°C (1500°F) | High stress applications |
Inconel X-750 Fastener Size Range
Inconel X-750 fasteners are manufactured across the full metric and imperial size range below. Custom sizes up to M140 bolts and M160 nuts can be produced on request using CNC machining, hot forging, or cold forging, with lengths cut to specification from 3mm up to 200mm standard.
| Fastener Type | Metric Sizes | Imperial Sizes | Standard |
| Screws | M1.2 to M48 | 1/4" to 2" | Per ASME B18.2.1 |
| Bolts | M1.2 to M120 | 3/16" to 2" | Per DIN 931 / ASTM |
| Stud Bolts | M4 to M100 | 1/4" to 3" | Per ASME B16.5 |
| Nuts | M2 to M80 (up to M160) | 1/4" to 4" | Per ASME B18.2.2 |
| Washers | M2 to M24 | 3/16" to 2" | Per ASME B18.22.1 |
| Threaded Rod | M2 to M72 | 1/4" to 3" | Per ASTM F593 |
| Length | 3 to 200 mm | Per customer spec | Custom lengths available |
Standards & Equivalent Grades
Inconel X-750 is recognized under several national and international standard systems. The table below cross-references the material across product forms, national designations, and trade names, so you can confirm equivalence regardless of which standard your drawing specifies.
| Standard Category | Standard Code | Scope / Notes | UNS | Werkstoff Nr. | JIS | Trade Names |
| Material Standard | ASTM B637 / ASME SB637 | Bar, forgings & flash-welded rings | UNS N07750 | 2.4669 | NCF X-750 | Inconel X750 | Pyromet X750 | Haynes X750 | Nickelvac X750 |
| Plate / Sheet / Strip | ASTM B906 / ASME SB906 | Plate and sheet forms | UNS N07750 | 2.4669 | NCF X-750 | Inconel X750 |
| Pipe / Tube | ASTM B163 / ASME SB163 | Seamless tube and pipe | UNS N07750 | 2.4669 | NCF X-750 | Inconel X750 |
| UNS Designation | UNS N07750 | North American standard | N07750 | 2.4669 | NCF X-750 | Inconel X750 |
| Werkstoff Nr. | WNR 2.4669 | European / German standard | UNS N07750 | 2.4669 | NCF X-750 | Inconel X750 |
| JIS Designation | NCF X-750 | Japanese Industrial Standard | UNS N07750 | 2.4669 | NCF X-750 | Inconel X750 |
| Head Markings | ASME B18.2.1 / DIN 931 | Hex head bolt dimensions | UNS N07750 | 2.4669 | NCF X-750 | Inconel X750 |
| Testing | ASTM E8 / ASTM A370 | Tensile and hardness testing | UNS N07750 | 2.4669 | NCF X-750 | Inconel X750 |
| Chemical Testing | ASTM E1019 / ASTM E1479 | Elemental analysis | UNS N07750 | 2.4669 | NCF X-750 | Inconel X750 |
| MTC / QC | EN 10204 3.1 / 3.2 | Material Test Certificates | UNS N07750 | 2.4669 | NCF X-750 | Inconel X750 |
Unifit Fastener holds: ISO 9001:2015 | PED 2014/68/EC | NACE MR0175/ISO 15156-2 | NORSOK M-650 | DFAR | MERKBLATT AD 2000 W2/W7/W10
Inconel X-750 Fasteners Applications & Industries
Inconel X-750's combination of high-temperature strength and corrosion resistance makes it the standard choice across the most demanding bolting applications in these industries:
| Industry / Application | Typical Use Cases | Why Inconel X750? |
| Aerospace & Defence | Jet engine components, aircraft structures, gas turbines | Withstands sustained high-temp mechanical loads |
| Oil & Gas / Petrochemical | Subsea bolting, wellhead equipment, pipelines | Excellent resistance to H2S & chloride environments |
| Nuclear Energy | Reactor internals, pressure vessel bolting | Reliable under radiation and elevated temperature |
| Marine & Offshore | Seawater desalination, offshore platforms | Superior chloride corrosion resistance |
| Chemical Processing | Reaction vessels, heat exchangers, flanges | Resists oxidising and reducing acids |
| Automotive / Motorsport | Turbocharger fasteners, exhaust manifolds | Creep resistance under cyclic thermal loading |
| Power Generation | Steam turbine bolting, high-temp springs | Long service life at elevated temperatures |
| High-Temperature Springs | Springs operating above 600°C | Maintains elasticity under sustained stress |
Inconel X-750 vs. Other Inconel Alloys — Comparison
Choosing between Inconel X-750, 718, 625, and 600 depends on the specific combination of strength, temperature, and corrosion resistance your application demands. The comparison below highlights where X-750 offers a distinct advantage.
| Property | Inconel X750 | Inconel 718 | Inconel 625 | Inconel 600 |
| Tensile Strength | 1267 MPa | 1380 MPa | 760 MPa | 550 MPa |
| Max Use Temp. | 816°C (1500°F) | 704°C (1300°F) | 980°C (1796°F) | 870°C (1600°F) |
| Density (g/cm³) | 8.28 | 8.19 | 8.22 | 8.19 |
| Corrosion Resistance | Excellent | Excellent | Outstanding | Good |
| Precipitation Hardening | Yes | Yes | No | No |
| Creep Resistance | Very High | High | High | Moderate |
| Cost Relative | Moderate | High | Higher | Lower |
| Key Alloys (ASTM) | B637 | B637 | B443 | B168 |
Summary: Inconel X750 is the optimal alloy when precipitation hardening is required for bolts and springs operating above 600°C under sustained load, offering a better strength-to-cost ratio than Inconel 718 for most industrial bolting applications.
Manufacturing Process & Quality Assurance
Every Inconel X-750 fastener manufactured by Unifit Fastener follows a rigorous, traceable production process aligned with ASTM B637 and customer-specific quality plans:
Manufacturing Processes:
- Hot Forging – for bolts and heavy-section fasteners requiring maximum grain integrity
- Cold Forging – for precision-tolerance screws and nuts up to M48
- CNC Machining – for custom profiles, flange bolts, and specialty fasteners
- Thread Rolling – for superior thread root fatigue resistance
- Heat Treatment – age hardening, solution anneal, and precipitation treatment per ASTM B637
Surface Finishing Options:
- Self-colour (as-manufactured)
- Black Oxide
- Nickel Plating / Zinc-Nickel Plating
- Bright Zinc Plated (BZP)
- Teflon Coating | Chrome Plating | Mirror Buffed
Testing & Inspection:
- Mechanical Testing: Tensile, Yield, Hardness, Elongation (ASTM E8 / A370)
- Chemical Analysis: PMI (Positive Material Identification), Spectro Analysis
- Non-Destructive Testing: X-Ray, Dye Penetrant (PT), Magnetic Particle (MT)
- Impact Testing, Flaring Test, Pitting Resistance Test, Flattening Test
- Torque Testing, Hydrogen Embrittlement Testing
Key Features & Benefits of Inconel X-750 Fasteners
Inconel X-750 delivers measurable performance advantages over standard bolting materials in high-temperature, high-load applications:
| Feature | Benefit to Your Application |
| Precipitation hardenable | Achieves tensile strengths up to 1267 MPa through controlled ageing — 3× stronger than 316 SS |
| Temperature resistance to 816°C | Maintains bolt clamping load without creep or relaxation where carbon steel fails |
| High nickel-chromium base (≥70% Ni) | Resists chloride stress corrosion cracking, seawater attack, and oxidising acids |
| Titanium + Aluminium additions | Form the γ' precipitate phase that provides the alloy's exceptional strength at temperature |
| Low creep rate | Critical for nuclear and turbine bolting where dimensional stability over decades is essential |
| Spring-quality elasticity | The only common Inconel alloy used for high-temperature springs — unique in the superalloy family |
| Full ASTM B637 certification | Ensures compliance with pressure equipment, nuclear, and aerospace procurement codes |
