GH139 Alloy

GH139 is a nickel-based precipitation-hardening wrought superalloy, strengthened primarily through the precipitation of γ’ phase (Ni₃Al, Ti) and supplemented by solid solution strengthening of chromium and molybdenum. It exhibits excellent high-temperature strength, outstanding creep resistance, and good thermal corrosion resistance, enabling long-term stable operation in harsh high-temperature environments ranging from 800℃ to 1000℃. This alloy is widely applied in high-end manufacturing industries that demand rigorous material performance, especially in scenarios involving long-term high-temperature load-bearing and cyclic thermal stress. 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 GH139 is approximately 8.20g/cm³, which is within the conventional density range of nickel-based superalloys. This characteristic facilitates accurate weight calculation during the structural design of high-temperature components, helping to balance the requirements of equipment lightweight design and load-bearing capacity.
2. Thermal Properties:

◦ Melting temperature range: 1360-1420℃. The moderate melting temperature range ensures the alloy maintains structural integrity without melting or severe softening under long-term high-temperature working conditions, providing a reliable material foundation for high-temperature load-bearing applications.

◦ Thermal expansion coefficient: It measures about 12.0×10⁻⁶/℃ in the 20-100℃ range, and increases moderately to approximately 13.8×10⁻⁶/℃ when heated to 20-900℃. The stable and gradual change in thermal expansion coefficient minimizes thermal stress caused by temperature fluctuations, significantly enhancing the alloy’s resistance to thermal fatigue cracking.

◦ Thermal conductivity: At 100℃, the thermal conductivity is around 15.5W/(m・K); at 900℃, it rises to roughly 24.0W/(m・K). The temperature-dependent increase in thermal conductivity facilitates efficient dissipation of local heat in high-temperature components, preventing excessive localized heating and subsequent degradation of material performance.

1. Mechanical Properties (After standard heat treatment: 1080℃ solid solution + 840℃ aging for 8h, air cooling):

◦ Yield strength (σ₀.₂, room temperature): ≥750MPa. This high yield strength enables the alloy to resist plastic deformation effectively under normal-temperature static loads, ensuring long-term structural stability of components.

◦ 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 critical high-temperature parts.

◦ Elongation (δ₅, room temperature): ≥15%. The moderate plastic deformation capacity ensures the alloy can be processed into required component shapes via forging, rolling, and other processes, while reducing the risk of cracking during manufacturing.

◦ High-temperature mechanical properties (at 900℃): The yield strength is ≥400MPa, the tensile strength is ≥500MPa, and the elongation is ≥10%. Even near its upper service temperature limit, the alloy retains excellent high-temperature strength and creep resistance, fully satisfying the long-term operational demands of high-temperature load-bearing structural parts (e.g., creep rupture strength ≥180MPa at 900℃ for 1000h).

1. Magnetic Properties: GH139 maintains weakly magnetic characteristics at room temperature, and as the temperature rises to the service temperature range (800-1000℃), its magnetic property gradually weakens to near non-magnetic. This property makes it suitable for applications in general magnetic field environments, and special attention should be paid to its magnetic influence when used near precision magnetic instruments.

3. Application Products

Leveraging its excellent comprehensive high-temperature performance, GH139 alloy has become a key material in advanced high-temperature equipment manufacturing, with core application products including:

• Aerospace Field: As a critical material for aero-engines and gas turbines, it is mainly used to manufacture high-temperature load-bearing components such as turbine disks (low-pressure and medium-pressure stages), compressor disks, and high-temperature fasteners. These parts operate in harsh environments with high-temperature (above 850℃) and high rotational speed, and GH139’s high-temperature strength and creep resistance ensure safe and stable operation of the engine. It is also applied in the structural parts of aerospace vehicles, such as high-temperature brackets and connectors in the propulsion system.
• Energy Field: In gas turbine power generation, it is used to produce turbine rotor disks and combustion chamber support structures, which withstand long-term erosion by high-temperature (above 800℃) and high-pressure gas. The alloy’s heat resistance and creep resistance improve the efficiency of gas turbines while extending equipment service life. In the nuclear energy field, it is utilized for manufacturing high-temperature structural parts in nuclear reactor auxiliary systems, resisting corrosion by high-temperature coolants and weak radiation.
• Petrochemical Field: It is ideal for manufacturing high-temperature centrifugal compressor impellers and high-temperature valve cores in petrochemical plants. These components operate at 700-900℃ in the presence of corrosive media (e.g., hydrocarbons and hydrogen), and GH139’s resistance to high-temperature corrosion and creep ensures continuous, stable operation of the equipment, reducing maintenance costs and production downtime.
• Other High-Temperature Fields: In the metallurgical industry, it is used to make high-temperature rolling mill rolls and heat treatment furnace baskets, withstanding long-term high-temperature oxidation and mechanical load. In the marine engineering field, it is applied to high-temperature exhaust system components of marine gas turbines, resisting the corrosion of high-temperature exhaust gas and marine atmospheric environment. It also finds use in high-temperature test equipment, such as high-temperature load-bearing fixtures for material creep testing machines.

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