GH3039 Superalloy
GH3039 is a nickel-based superalloy strengthened by solid solution (primarily with chromium, tungsten, and molybdenum) and trace precipitation strengthening elements. It is valued for its balanced combination of high-temperature strength, oxidation resistance, and excellent processability, making it a widely used material in high-temperature industrial and aerospace applications. Below is a detailed overview of its composition, properties, processing, and applications:
1. Chemical Composition
The chemical composition of GH3039 is carefully optimized to enhance high-temperature performance and stability. Key elements and their typical ranges are as follows:
Element Content Range (%) Role in the Alloy
Nickel (Ni) Base element (~57-63) Forms the matrix, providing structural stability and resistance to high-temperature degradation.
Chromium (Cr) 19.0-22.0 Critical for oxidation and corrosion resistance, forming a dense chromium oxide film that protects the alloy at high temperatures.
Tungsten (W) 1.8-2.8 Enhances high-temperature strength through solid-solution strengthening, improving creep resistance.
Molybdenum (Mo) 1.8-2.8 Works with tungsten to boost solid-solution strengthening, particularly at intermediate to high temperatures.
Titanium (Ti) 0.15-0.35 Aids in grain refinement and minor precipitation strengthening, improving room-temperature toughness.
Aluminum (Al) 0.3-0.7 Promotes oxidation resistance and helps stabilize the protective oxide layer at elevated temperatures.
Carbon (C) ≤0.08 Controls grain boundary strengthening by forming fine carbides, enhancing creep resistance.
Iron (Fe) ≤3.0 Minor impurity or additive to adjust alloy ductility and processability.
2. Physical Properties
GH3039 exhibits physical properties tailored for consistent performance in high-temperature environments:
Density: Approximately 8.30 g/cm³, lighter than some high-strength superalloys, making it suitable for weight-sensitive applications.
Melting Point: 1370-1400°C, ensuring stability in extreme heat conditions without melting or structural breakdown.
Thermal Conductivity: Increases with temperature, ranging from ~11.2 W/(m·℃) at 100°C to ~24.5 W/(m·℃) at 1000°C, facilitating effective heat dissipation.
Coefficient of Linear Expansion: 12.6×10⁻⁶/℃ (20-100°C) and 16.4×10⁻⁶/℃ (20-1000°C). Compatibility with mating materials must be considered to minimize thermal stress during temperature cycles.
Magnetic Property: Non-magnetic, ideal for applications requiring magnetic neutrality, such as aerospace electronics and precision instruments.
3. Mechanical Properties
GH3039’s mechanical performance is characterized by reliable strength and ductility across a wide temperature range:
Tensile Strength:
At room temperature: Tensile strength (Rm) ≥ 630 MPa; yield strength (Rp0.2) ≥ 270 MPa.
At 800°C: Tensile strength remains ≥ 440 MPa; yield strength ≥ 210 MPa, ensuring load-bearing capacity in high-temperature service.
Ductility: Elongation (A5) ≥ 30% at room temperature and ≥ 20% at 800°C, providing good formability and resistance to brittle fracture.
Creep Resistance: Exhibits low creep rates under long-term high-temperature stress (e.g., creep rupture strength ≥ 140 MPa for 1000 hours at 800°C), critical for extended service life in hot components.
Oxidation Resistance: Maintains structural integrity in air or oxidizing atmospheres up to 1000°C, with minimal weight loss from oxidation even after prolonged exposure.
4. Processing Performance
GH3039 is known for its excellent processability, enabling fabrication into complex shapes via various methods:
Hot Working:
Suitable for hot forging, rolling, and extrusion. Optimal temperature range: 1100-1200°C, where the alloy exhibits high plasticity and low deformation resistance.
Slow cooling after hot working helps reduce residual stress and prevent cracking.
Cold Working:
Can be cold-rolled, drawn, or stamped with moderate work hardening. Intermediate annealing (at 1050-1100°C) restores ductility for further processing.
Welding:
Compatible with common welding techniques, including gas tungsten arc welding (GTAW) and resistance welding.
Pre-weld cleaning (to remove oxides and contaminants) and post-weld annealing (1050-1100°C) are recommended to ensure joint strength and corrosion resistance.
Heat Treatment:
Standard treatment: Solution annealing at 1150-1200°C (held for 1-2 hours) followed by air cooling, which optimizes grain structure and 均匀 izes alloying elements for consistent performance.
5. Application Fields
GH3039’s versatility and balanced properties make it a staple in high-temperature industries:
Aerospace:
Components of aero-engines, such as combustion chambers, afterburner liners, and exhaust system parts, where high-temperature oxidation resistance and strength are critical.
Structural parts for spacecraft thermal protection systems and rocket engine accessories.
Energy and Power:
Hot-end components of industrial gas turbines, including transition ducts, flame holders, and heat shields.
High-temperature heat exchangers, furnace liners, and radiant tubes in petrochemical, metallurgical, and power generation plants.
Industrial Manufacturing:
High-temperature furnace fixtures, conveyor belts, and rollers for heat treatment, glass melting, and ceramic sintering processes.
Wear-resistant and corrosion-resistant parts in high-temperature mechanical equipment.
In summary, GH3039 is a reliable nickel-based superalloy prized for its combination of high-temperature strength, oxidation resistance, and ease of processing. Its broad application range underscores its importance in enabling safe and efficient operation of critical components in extreme thermal environments.