GH3128 Alloy

GH3128 is a Ni-Cr-based solid solution strengthened wrought superalloy, primarily reinforced by the synergistic solid solution effect of chromium, tungsten, and molybdenum. It exhibits exceptional high-temperature oxidation resistance (up to 1200℃ in air), superior thermal corrosion resistance, and stable mechanical properties at both room and elevated temperatures, enabling long-term reliable operation in harsh high-temperature environments ranging from 900℃ to 1150℃. This alloy is widely applied in high-end manufacturing industries with strict requirements for material heat resistance, corrosion resistance, and high-temperature strength, especially in scenarios involving continuous ultra-high-temperature exposure, corrosive media (e.g., sulfur-containing gases), and medium-to-high load-bearing. The following is a detailed breakdown of its chemical composition, physical properties, and application products.

1. Chemical Composition (Mass Fraction, %)

2. Physical Properties

1. Density: At room temperature, the density of GH3128 is approximately 8.70g/cm³, which is slightly higher than that of Fe-Ni-Cr-based superalloys (e.g., GH3039) due to the addition of high-density tungsten. This characteristic requires weight optimization during structural design of rotating components (e.g., turbine disks), while its outstanding high-temperature strength effectively offsets the impact of higher density on load-bearing efficiency, making it suitable for high-stress ultra-high-temperature parts.
2. Thermal Properties:

◦ Melting temperature range: 1370-1430℃. The stable melting temperature range ensures the alloy maintains structural integrity without melting or severe softening under long-term ultra-high-temperature (up to 1150℃) working conditions, providing a reliable material foundation for high-temperature applications such as aero-engine turbine blades and industrial furnace core components.

◦ Thermal expansion coefficient: It measures about 11.2×10⁻⁶/℃ in the 20-100℃ range, and increases moderately to approximately 13.8×10⁻⁶/℃ when heated to 20-1000℃. The low and gradual change in thermal expansion coefficient minimizes thermal stress caused by rapid temperature fluctuations (e.g., engine start-stop cycles), significantly enhancing the alloy’s resistance to thermal fatigue cracking—critical for components undergoing frequent cyclic heating and cooling (e.g., combustion chamber liners and exhaust manifolds).

◦ Thermal conductivity: At 100℃, the thermal conductivity is around 14.0W/(m・K); at 1000℃, it rises to roughly 22.5W/(m・K). The temperature-dependent increase in thermal conductivity promotes efficient heat transfer and dissipation in high-temperature components, avoiding excessive localized heat accumulation (which may cause creep acceleration) and subsequent degradation of material mechanical properties, thus extending the service life of parts by 40% compared to conventional Ni-Cr alloys.

1. Mechanical Properties (After standard heat treatment: 1150-1200℃ solid solution, water cooling + 800-850℃ aging for 2h, air cooling):

◦ Yield strength (σ₀.₂, room temperature): ≥700MPa. This high yield strength enables the alloy to effectively resist plastic deformation under normal-temperature static loads, ensuring structural stability of components such as high-load high-temperature fasteners and pressure-bearing structural parts.

◦ Tensile strength (σᵦ, room temperature): ≥900MPa. The excellent tensile strength allows the alloy to withstand complex external forces (e.g., tension, bending, and shear) in engineering applications, meeting the load-bearing requirements of key ultra-high-temperature parts in aero-engines and industrial gas turbines.

◦ Elongation (δ₅, room temperature): ≥20%. The reliable plastic deformation capacity makes the alloy processable into complex-shaped components via forging, rolling, and precision machining processes, reducing the risk of cracking during manufacturing (especially for thick-walled parts) while maintaining structural integrity.

◦ High-temperature mechanical properties (at 1000℃): The yield strength is ≥350MPa, the tensile strength is ≥450MPa, and the elongation is ≥12%. More importantly, its creep rupture strength reaches ≥180MPa at 1000℃ for 1000h and ≥80MPa at 1100℃ for 1000h—far exceeding the performance of GH3039—fully satisfying the long-term ultra-high-temperature load-bearing demands of components such as turbine blades (medium-pressure stages) and furnace tubes in petrochemical cracking units.

1. Magnetic Properties: GH3128 exhibits non-magnetic characteristics across its entire service temperature range (room temperature to 1150℃). This feature makes it highly suitable for applications in magnetic field-sensitive environments, such as high-temperature components near electromagnetic induction equipment (e.g., nuclear reactor magnetic control systems), precision magnetic instruments, and aerospace navigation sensors, without interfering with the normal operation of surrounding devices.

3. Application Products

Leveraging its excellent comprehensive ultra-high-temperature performance (especially superior high-temperature strength and oxidation resistance compared to GH3039), GH3128 alloy has become a core material in ultra-high-temperature high-end equipment manufacturing, with core application products including:

• Aerospace Field: It is mainly used to manufacture high-load ultra-high-temperature components such as aero-engine turbine blades (medium-pressure stages), turbine outer rings, combustion chamber liners (hot zones), and afterburner nozzles. These parts operate in environments with ultra-high-temperature (950-1100℃), high-pressure gas, and fuel erosion; GH3128’s high-temperature strength and oxidation resistance ensure long-term stable operation (service life up to 30,000 hours for aero-engine parts). It is also applied in the thermal protection systems of hypersonic aircraft, such as heat shield panels and propulsion system structural brackets, resisting aerodynamic heating (up to 1150℃) during high-speed flight.
• Energy Field: In industrial gas turbine power generation (for peak-shaving power plants), it is used to produce turbine rotor blades (medium-pressure stages) and combustion chamber support rings, which withstand long-term exposure to high-temperature (900-1050℃) and high-pressure gas. The alloy’s thermal stability and creep resistance improve the efficiency of gas turbines (up to 56% for combined cycle power generation) while extending the equipment’s service life to over 80,000 hours. In waste incineration power plants, it is utilized for manufacturing high-temperature flue gas heat exchanger tubes, resisting corrosion by high-temperature (800-950℃) sulfur-containing and chlorine-containing flue gases.
• Petrochemical Field: It is ideal for manufacturing ultra-high-temperature furnace tubes in petrochemical ethylene cracking units and high-temperature reactor cores in coal-to-olefins projects. These components operate at 1000-1100℃ in the presence of aggressive corrosive media (e.g., high-temperature hydrocarbons, hydrogen, and sulfur-containing gases); GH3128’s resistance to high-temperature corrosion and creep ensures continuous, stable production (reducing cracking risks of furnace tubes by 60%), minimizing production interruptions and maintenance costs by 45%. It is also widely used in the manufacturing of catalyst regeneration furnace liners and high-temperature gas separation membranes in natural gas processing.
• Other High-Temperature Fields: In the metallurgical industry, it is used to make high-temperature furnace rolls (for stainless steel continuous annealing lines) and vacuum induction melting furnace crucibles, withstanding long-term ultra-high-temperature oxidation (up to 1200℃) and mechanical wear. In the nuclear energy field, it is applied to high-temperature heat exchanger tubes in advanced nuclear reactors (e.g., molten salt reactors), resisting corrosion by high-temperature molten salts (up to 1100℃) and weak radiation. In high-temperature test equipment, it is used as sample holders for material ultra-high-temperature oxidation testing and high-load creep test fixtures, providing reliable material performance data for research on ultra-high-temperature materials. Additionally, it is utilized in the manufacturing of high-temperature resistant components for aerospace ground test equipment (e.g., rocket engine test stands).