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Material selection for jet engine rotating components requires a stringent balance of high-temperature strength, fatigue resistance, and microstructural stability. GH738 (UNS N07001 / Waspaloy) is a precipitation-hardening nickel-based superalloy specifically engineered for these critical applications. With a service capability up to 815°C (1500°F), it offers superior yield strength and creep resistance compared to many conventional high-temperature alloys. Shanghai COCESS Special Alloys Co., Ltd supplies aerospace-grade GH738 in bar, forging stock, ring rolls, and wire, fully compliant with ASTM B637, AMS 5708, and AMS 5706 specifications, ensuring the material integrity demanded by global aero-engine manufacturers and MRO facilities.
GH738 achieves its exceptional properties through a high volume fraction of gamma-prime (γ') precipitates, Ni₃(Al, Ti), distributed within a solid-solution strengthened matrix. The high cobalt content (12-15%) is vital for stabilizing the gamma prime phase and enhancing high-temperature creep resistance.
Chemical Composition (Weight %):
Nickel (Ni): Balance (Approx. 55-58%)
Chromium (Cr): 18.0 – 21.0% (Provides oxidation and sulfidation resistance in gas turbine atmospheres)
Cobalt (Co): 12.0 – 15.0% (Solid solution strengthening and γ' phase stability)
Molybdenum (Mo): 3.5 – 5.0% (Solid solution strengthening)
Titanium (Ti): 2.75 – 3.25% (Primary γ' precipitate former)
Aluminum (Al): 1.20 – 1.60% (Primary γ' precipitate former)
Iron (Fe): ≤ 2.0%
Carbon (C): 0.03 – 0.10% (Forms carbides for grain boundary strengthening)
Boron (B): 0.003 – 0.010% (Segregates to grain boundaries to improve strength and ductility)
Zirconium (Zr): 0.02 – 0.08% (Enhances grain boundary cohesion)
The alloy exhibits excellent retention of properties at elevated temperatures, making it suitable for continuous service in the 650°C to 815°C range for high-stress rotating parts.
Physical Constants:
Density: 8.22 g/cm³ (0.297 lb/in³)
Melting Range: 1330 – 1360 °C (2425 – 2475 °F)
Elastic Modulus (20°C): ~214 GPa (31 x 10³ ksi)
Coefficient of Thermal Expansion (20-100°C): 12.47 x 10⁻⁶/°C
Thermal Conductivity: 16.8 W/m·K at 360°C, increasing to 28.0 W/m·K at 985°C
Typical Mechanical Properties (Fully Heat Treated Condition):
Room Temp Tensile Strength: 1200 – 1380 MPa (174 – 200 ksi)
Room Temp Yield Strength (0.2%): 800 – 895 MPa (116 – 130 ksi)
Room Temp Elongation: 15 – 25%
Hardness: 32 – 42 HRC
815°C (1500°F) Tensile Strength: ~400 MPa (58 ksi)
750°C Stress Rupture: Exceeds 100 hours at 530 MPa (approx. 77 ksi)
700°C Fatigue Strength (10⁷ cycles): ≥ 400 MPa
GH738 is a standard material for critical rotating and high-stress stationary parts in aerospace gas turbines:
Turbine Discs (Rotors): The alloy's superior low-cycle fatigue (LCF) life and high yield strength at 650°C-760°C make it ideal for discs that hold turbine blades, managing immense centrifugal forces.
Turbine Blades: Used for blades operating in the high-pressure turbine section where temperatures are extreme but below 815°C.
High-Temperature Shafts and Spacers: Components requiring dimensional stability and strength under rotational stress.
High-Temperature Fasteners: Bolts, nuts, and studs used to secure casings and components in the hot section, where they must resist stress relaxation and maintain preload at temperatures up to 730°C-815°C.
Shanghai COCESS provides GH738 (Waspaloy) materials strictly according to the following key aerospace and industrial standards:
Bars, Forgings, Rings: ASTM B637, AMS 5708, AMS 5706
Sheet, Plate, Strip: AMS 5544
Wire: AMS 5828
All materials are supplied with full traceability, ultrasonic testing (UT) options, and EN 10204 3.1/3.2 certification. For technical datasheets, current stock sizes, or inquiries regarding GH738 for your jet engine projects, contact Shanghai COCESS Special Alloys Co., Ltd.
