Introduction

Inconel X-750 (UNS N07750 / GH4145 / W.Nr. 2.4669) is a precipitation-hardenable nickel-chromium superalloy that derives its exceptional strength from the precipitation of γ′ (Ni₃(Al,Ti)) phases during controlled aging heat treatment. Unlike solid-solution strengthened alloys, X-750's core distinction is its ability to achieve significant age hardening, delivering high strength and creep resistance across a wide temperature range. The alloy contains approximately 70% nickel, 14–17% chromium, 5–9% iron, 2.25–2.75% titanium, 0.4–1.0% aluminum, and 0.7–1.2% niobium.

This nickel base superalloy is defined by ASTM B637 for bar and rod, ASTM B670 for plate and sheet, and ASTM B983 for seamless pipe and tube. It is also available in wire, spring wire, forging, and fastener forms. With high strength up to 1300°F (704°C), oxidation resistance up to 1800°F (982°C), and outstanding relaxation resistance below 1000°F (540°C), Inconel X-750 is the preferred material for aerospace engines, gas turbines, nuclear reactors, high-temperature springs and fasteners, and power generation equipment. Available in a full range of product forms including GH4145 round bar, Inconel X-750 plate, sheet, pipe, tube, and spring wire.

Chemical components（%）

Mechanical properties

Physical properties

Inconel X-750 Round Bar Nickel-Based Alloy Available Products and Standard

1. GB/T 14992 (Superalloys – Classification and Specifications)

Type: Round Bar / Sheet / Strip / Wire / Tube / Forgings / Ring

Size Range:

• Inconel X-750 Superalloy Wire: 0.1 – 15.0 mm dia

• Inconel X-750 Superalloy Strip: 0.05 – 5.0 mm thick × 5 – 500 mm wide

• Inconel X-750 Superalloy Round Bar: 8 – 355 mm dia

• Inconel X-750 Superalloy Sheet / Plate: 0.5 – 180 mm thick

• Inconel X-750 Superalloy Seamless Tube: Custom sizes available

Surface: Annealed, Bright, Pickled, Ground

Testing: Chemical analysis, mechanical test (tensile strength, yield strength, elongation), hardness test, high-temperature stress rupture test, relaxation resistance test, dimensional inspection

2. ASTM B637 / ASTM B637-24 (Standard Specification for Precipitation Hardening Nickel Alloy Bar, Rod, Wire, and Forging)

Grade: GH4145 / Inconel X-750 / UNS N07750 / NiCr15Fe7TiAl
Type: Round Bar / Rod / Wire / Forging / Ring

Size Range:

• Inconel X-750 Superalloy Round Bar: 8 – 355 mm dia (hot rolled or cold drawn)

• Inconel X-750 Superalloy Wire: 0.1 – 15.0 mm dia (coils or straight)

• Inconel X-750 Superalloy Forging / Ring: Custom sizes available

Surface: Annealed, Pickled, Ground, Turned, Bright

Testing: Chemical analysis, mechanical test (tensile, yield, elongation), hardness test, stress rupture test, relaxation resistance test, ultrasonic test, dimensional inspection

3. ASTM B906 (Standard Specification for General Requirements for Nickel Alloy Plate, Sheet, and Strip)

Grade: GH4145 / Inconel X-750 / UNS N07750
Type: Sheet / Plate / Strip

Size Range:

• Inconel X-750 Superalloy Sheet / Plate: 0.5 – 180 mm thick (hot rolled or cold rolled)

• Inconel X-750 Superalloy Strip: 0.05 – 5.0 mm thick × up to 500 mm wide (coils)

Surface: Annealed, Pickled, Bright, Polished

Testing: Chemical analysis, mechanical test (tensile, yield, elongation), hardness test, dimensional inspection

Applications

1. Aerospace & Jet Engine Components

• For rocket engine thrust chambers and fuel nozzles, Inconel X-750 round bar provides high-temperature strength and oxidation resistance up to 1800°F (982°C), ensuring reliable performance in extreme combustion environments.

• For jet engine turbine blades and wheels, the precipitation-hardened structure of Alloy X-750 maintains mechanical integrity at temperatures up to 1300°F (704°C), where conventional alloys would soften.

• For thrust reversers and hot-air ducting systems, UNS N07750 seamless pipe offers resistance to thermal fatigue and oxidation, ensuring long service life in airframe hot sections.

• For aircraft structural fasteners and bolting, Inconel X-750 fasteners deliver high strength and relaxation resistance that maintain clamping force through thousands of thermal cycles from sub-zero to 1200°F.

2. Gas Turbines & Power Generation

• For gas turbine rotor blades and wheels, GH4145 round bar provides creep resistance and high-temperature strength that enable operation in the hottest sections of the turbine.

• For turbine bolts and structural members, Inconel X-750 bolts offer relaxation resistance at elevated temperatures, ensuring bolted joints remain tight through extended service intervals.

• For combustor components and transition ducts, Alloy X-750 plate delivers oxidation resistance up to 1800°F (982°C), protecting against flame impingement and hot gas erosion.

• For power generation fasteners and springs, UNS N07750 wire combines strength and corrosion resistance that is unmatched by conventional alloy steels in high-temperature environments.

3. High-Temperature Springs & Fasteners

• For high-temperature springs operating from cryogenic to 1300°F (704°C), Inconel X-750 spring wire provides resistance to stress relaxation, ensuring consistent spring force through wide temperature ranges.

• For turbine and exhaust system springs, GH4145 wire maintains elastic properties in the most demanding thermal cycling environments.

• For high-strength bolts and fasteners for gas turbines and rocket engines, Alloy X-750 bar combines high tensile strength (up to 200 ksi) with relaxation resistance to ensure joint integrity under extreme conditions.

• For spring washers and Belleville springs in nuclear and aerospace applications, Inconel X-750 forgings deliver creep resistance and oxidation protection for long-term reliability in safety-critical components.

4. Nuclear Reactor Systems

• For reactor internal bolts, pins, and spring components, UNS N07750 round bar maintains mechanical properties under neutron irradiation and high-temperature water environments.

• For control rod drive mechanisms and fuel assembly components, Inconel X-750 seamless pipe provides creep resistance and corrosion resistance for reliable operation through extended fuel cycles.

• For nuclear pressure vessel internals, Alloy X-750 plate offers resistance to stress corrosion cracking and relaxation, making it suitable for safety-critical applications.

FAQ – Inconel X-750 / GH4145 Superalloy

Q: What is the difference between Inconel X-750 and Inconel 718?

A: Both are precipitation-hardenable nickel superalloys, but they are optimized for different applications. Inconel X-750 is strengthened by aluminum and titanium (forming γ′ precipitates) and offers excellent relaxation resistance, making it the preferred choice for high-temperature springs and fasteners. Inconel 718 is strengthened by niobium (forming γ″ precipitates) and offers higher tensile strength and better weldability, making it more suitable for turbine discs and complex welded structures.

Q: What is the maximum operating temperature for Inconel X-750?

A: Inconel X-750 is suitable for continuous service up to 1300°F (704°C) and offers oxidation resistance up to 1800°F (982°C). Its excellent relaxation resistance is most valuable below 1000°F (540°C). Much of the precipitation hardening effect is lost above 1300°F, though heat-treated material retains useful strength up to 1800°F.

Q: What are the key ASTM standards for Inconel X-750?

A: ASTM B637 covers bar, rod, and wire (with ASME SB637 for pressure vessel applications); ASTM B670 covers plate, sheet, and strip (with ASME SB670); ASTM B983 covers seamless pipe and tube. Aerospace specifications include AMS 5667 and AMS 5668 for bar, AMS 5669 for forging, and AMS 5698/5699 for wire and spring wire.

Q: What is the difference between GH4145 and Inconel X-750?

A: GH4145 is the Chinese designation for the same material as Inconel X‑750 (UNS N07750). Both refer to the same nickel-chromium precipitation-hardenable superalloy with identical composition and properties. The two designations are interchangeable — GH4145 is used in Chinese standards, while Inconel X‑750 is the international trade name.

We are a trusted Inconel X-750 Supplier and GH4145 Superalloy Manufacturer, China‑based, serving aerospace manufacturers, gas turbine builders, nuclear industry suppliers, and high-performance engineering contractors worldwide. All products comply with ASTM B637 / ASTM B670 / ASME SB637 with EN 10204 3.1 mill certificates, PMI verification, and dimensional inspection reports. We offer Inconel X‑750 round bar, GH4145 bar, plate, sheet, pipe, tube, wire, spring wire, forgings, fasteners, and bolts in custom sizes, with cut‑to‑length, precision grinding, and CNC machining services. Bright drawn, precision ground, and heat treated options available. Contact us at info@monokj.com for size chart, pricing, or custom requirements.