GH2135 Alloy

GH2135 is a high-performance Fe-Ni-Cr-based precipitation-hardening wrought superalloy, optimized based on the classic GH2132 alloy. It achieves strengthening primarily through the coherent precipitation of γ’ phase (Ni₃Ti, Al, Nb) and is supplemented by solid solution strengthening from chromium (Cr) and molybdenum (Mo). This alloy exhibits superior high-temperature creep resistance, enhanced thermal corrosion resistance, and more balanced mechanical properties at elevated temperatures compared to GH2132, enabling long-term reliable operation in harsh medium-to-high temperature environments ranging from 700℃ to 850℃.

Notably, GH2135 maintains stable performance even in environments with high-temperature steam containing trace sulfur or weak acidic media. Its improved hot workability and weldability make it a cost-effective alternative to high-nickel superalloys (e.g., Inconel 718) in high-demand medium-temperature scenarios. It is widely used in advanced aerospace, ultra-supercritical power generation, and high-end petrochemical industries where material high-temperature load-bearing capacity and corrosion resistance are critical. The following is a comprehensive breakdown of its chemical composition, physical properties, and application products.

1. Chemical Composition (Mass Fraction, %)

2. Physical Properties

2.1 Basic Physical Parameters

• Density: Approximately 8.05g/cm³ at room temperature (25℃), which is slightly higher than GH2132 (7.98g/cm³) due to the addition of niobium, but still 7-9% lower than nickel-based superalloys (e.g., GH3128: 8.70g/cm³). This low-density advantage is crucial for weight-sensitive components such as large turbine disks and aerospace structural parts, reducing equipment overall weight by 4-10% compared to high-nickel alternatives.
• Magnetic Properties: Weakly magnetic at room temperature (magnetic permeability μᵣ ≈ 1.006-1.012); magnetic property gradually fades as temperature rises, becoming nearly non-magnetic (μᵣ ≈ 1.002) in the service temperature range (700-850℃). This makes it suitable for applications near general electromagnetic equipment, though caution is still needed for high-precision magnetic sensors (e.g., aerospace navigation systems and nuclear reactor magnetic measurement devices).
• Melting Temperature Range: 1350-1410℃ (liquidus: ~1410℃; solidus: ~1350℃). The narrow melting range ensures uniform solidification during casting and forging, reducing internal defects (e.g., shrinkage porosity) and improving component structural integrity, which is critical for high-pressure load-bearing parts.
• Thermal Expansion Coefficient (CTE):

2.2 Thermal Properties

◦ 20-100℃: ~12.6×10⁻⁶/℃

◦ 20-600℃: ~14.0×10⁻⁶/℃

◦ 20-800℃: ~15.2×10⁻⁶/℃

◦ 20-850℃: ~15.6×10⁻⁶/℃

The more gradual CTE increase (compared to GH2132) minimizes thermal stress during frequent temperature cycling (e.g., aero-engine start-stop or boiler load adjustment), reducing thermal fatigue cracking risk by 35-45% compared to conventional Fe-Cr-Ni alloys.

• Thermal Conductivity (λ):

◦ 100℃: ~15.8W/(m·K)

◦ 500℃: ~19.2W/(m·K)

◦ 800℃: ~21.8W/(m·K)

◦ 850℃: ~22.5W/(m·K)

The temperature-dependent conductivity improvement promotes efficient heat dissipation in high-temperature components, avoiding localized overheating (a major cause of creep acceleration) and extending part service life by 20-25% compared to GH2132.

2.3 Mechanical Properties (After Standard Heat Treatment: 1000-1030℃ solid solution for 1h, water cooling + 720-750℃ aging for 12h, air cooling)

Key Notes:

• The higher room-temperature strength (σᵦ ≥1080MPa) compared to GH2132 meets the load-bearing requirements of high-pressure fasteners and advanced compressor disks in next-generation aero-engines;
• At 700℃ (a typical service temperature for ultra-supercritical power plant components), the creep rupture strength (≥480MPa) is 14-19% higher than that of GH2132, ensuring long-term structural stability under high-temperature and high-pressure conditions;
• Even at 850℃ (near its upper service limit), the retained elongation (≥8%) and creep rupture strength (≥180MPa) prevent brittle fracture during emergency shutdowns or thermal shocks, expanding its application range to higher-temperature scenarios.

3. Application Products & Industry Scenarios

3.1 Aerospace Field

GH2135 is a core material for high-performance medium-temperature components in advanced aero-engines and aerospace vehicles, with typical applications including:

• Advanced Aero-engine Components: High-pressure compressor disks (rotational speed up to 16,000 rpm) and high-temperature turbine blades (low-pressure stages) in large bypass ratio turbofan engines. These parts operate in environments with 700-800℃ gas and cyclic thermal stress; the alloy’s creep resistance ensures a service life of up to 30,000 flight hours.
• Aerospace Propulsion System Parts: High-temperature fasteners (used in combustion chamber casings and turbine stators) and fluid pipeline connectors in rocket auxiliary propulsion systems. The alloy’s enhanced thermal corrosion resistance (to rocket fuel combustion by-products) improves reliability during long-duration space missions.

3.2 Energy Field

3.2.1 Ultra-supercritical (USC) Thermal Power Generation

In advanced USC power plants (steam parameters: 620-650℃, 30-35MPa), GH2135 is used for:

• High-temperature Steam Valves: Main control valves and stop valves in the main steam pipeline, resisting high-temperature steam erosion and ensuring seal integrity for over 120,000 hours.
• Boiler Superheater Headers: High-temperature headers (600-620℃) connecting final superheaters, where its excellent thermal fatigue resistance reduces leakage risks caused by frequent load changes.
• High-pressure Turbine Blades: Blades in the first three stages of high-pressure turbines, where the alloy’s creep resistance (to high-temperature steam) extends maintenance intervals by 24-30 months.

3.2.2 Advanced Industrial Gas Turbines

For gas turbines used in combined cycle power plants (turbine inlet temperature: 1100-1200℃), the alloy is applied to:

• Compressor Impellers: High-pressure compressor impellers (stage 10-15), withstanding centrifugal forces up to 35,000g and 750℃ air temperature.
• Combustion Chamber Liner Supports: Heat-resistant brackets and support rings around combustion chamber liners, resisting radiant heat and cyclic thermal stress without deformation.

3.3 Petrochemical Field

In large-scale petrochemical plants (especially ethylene cracking and heavy oil hydrogenation units), GH2135 is used for:

• High-temperature Centrifugal Compressor Disks: Disks in ethylene cracking gas compressors (operating temperature: 700-750℃, medium: hydrocarbon gas with trace sulfur), where its creep resistance prevents disk deformation under long-term high-speed rotation (up to 13,000 rpm).
• Hydrogenation Reactor Internals: High-pressure valve stems and catalyst support grids in heavy oil hydrogenation reactors (pressure: 18-22MPa, temperature: 750-800℃), resisting hydrogen embrittlement and sulfur corrosion.
• Cracking Furnace Tubes: Medium-temperature furnace tubes (800-850℃) in ethylene cracking furnaces, reducing maintenance costs by 35-40% compared to 310S stainless steel due to improved creep resistance.
• Metallurgical Industry: High-temperature rolling mill work rolls for stainless steel hot rolling (working temperature: 750-800℃) and vacuum heat treatment furnace baskets (used for annealing high-strength titanium alloys). The alloy’s wear resistance and oxidation resistance extend roll service life by 60% and reduce basket replacement frequency.
• Marine Engineering: High-temperature exhaust manifold components in large marine gas turbines (fuel: low-sulfur marine diesel), resisting combined corrosion from 700-750℃ exhaust gas and marine salt spray.
• High-temperature Test Equipment: Sample holders for high-temperature creep testing (700-850℃) and high-load fixture components in material performance testing machines, providing stable support for long-term tests (up to 8,000 hours) and ensuring accurate test data.
• Hot Working: Forging temperature range: 1120-1200℃; initial forging temperature should not exceed 1200℃ to avoid grain coarsening, and final forging temperature should not be lower than 980℃ to prevent grain boundary cracking;
• Cold Working: Cold rolling or stamping can be performed at room temperature, with intermediate annealing (920-960℃, 1h) recommended after 25-35% deformation to restore ductility (higher than GH2132 due to niobium addition);
• Heat Treatment: The two-step process (solid solution + aging) must be strictly controlled—over-aging (above 780℃) will cause γ’ phase coarsening and significant strength degradation, while under-aging (below 700℃) will result in insufficient precipitation strengthening and reduced high-temperature performance.

3.4 Metallurgical & Other High-end Fields

4. Processing & Heat Treatment Recommendations

This comprehensive performance and application profile makes GH2135 a high-performance, cost-effective superalloy for advanced medium-to-high temperature high-end manufacturing, perfectly balancing high-temperature strength, corrosion resistance, and processability for next-generation industrial equipment.