GH2132 Alloy

GH2132 (also known as A-286 in international standards) is a classic Fe-Ni-Cr-based precipitation-hardening wrought superalloy, primarily strengthened by the coherent precipitation of γ’ phase (Ni₃Ti, Al) and supplemented by solid solution strengthening of chromium (Cr) and molybdenum (Mo). It stands out for its excellent high-temperature creep resistance, superior thermal fatigue resistance, and balanced mechanical properties at both room and elevated temperatures, enabling long-term reliable operation in harsh medium-to-high temperature environments ranging from 650℃ to 800℃.

Notably, this alloy maintains stable performance even in environments with low-sulfur steam or weak corrosive media, and its good weldability and machinability make it a cost-effective alternative to high-nickel superalloys in medium-temperature scenarios. It is widely used in aerospace, energy, petrochemical, and metallurgical industries where material high-temperature load-bearing capacity and processability 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 7.98g/cm³ at room temperature (25℃), which is 8-10% lower than nickel-based superalloys (e.g., GH3128: 8.70g/cm³) and close to carbon steel (7.85g/cm³). This low-density advantage is critical for weight-sensitive components such as large turbine disks and aerospace structural parts, reducing equipment overall weight by 5-12% compared to high-nickel alternatives.
• Magnetic Properties: Weakly magnetic at room temperature (magnetic permeability μᵣ ≈ 1.005-1.010); magnetic property gradually fades as temperature rises, becoming nearly non-magnetic (μᵣ ≈ 1.001) in the service temperature range (650-800℃). 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).
• Melting Temperature Range: 1360-1420℃ (liquidus: ~1420℃; solidus: ~1360℃). The narrow melting range ensures uniform solidification during casting and forging, reducing internal defects and improving component structural integrity.
• Thermal Expansion Coefficient (CTE):

2.2 Thermal Properties

◦ 20-100℃: ~12.8×10⁻⁶/℃

◦ 20-500℃: ~14.3×10⁻⁶/℃

◦ 20-800℃: ~15.5×10⁻⁶/℃

The gradual CTE increase minimizes thermal stress during temperature cycling (e.g., engine start-stop or boiler load adjustment), reducing thermal fatigue cracking risk by 30-40% compared to alloys with abrupt CTE changes.

• Thermal Conductivity (λ):

◦ 100℃: ~16.0W/(m·K)

◦ 500℃: ~19.5W/(m·K)

◦ 800℃: ~22.0W/(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.

2.3 Mechanical Properties (After Standard Heat Treatment: 980-1000℃ solid solution for 1h, water cooling + 700-720℃ aging for 16h, air cooling)

Key Notes:

• The high room-temperature strength (σᵦ ≥1030MPa) meets the load-bearing requirements of high-pressure fasteners and compressor disks;
• At 700℃ (a typical service temperature for gas turbine components), the creep rupture strength (≥420MPa) is 20-25% higher than that of conventional Fe-Cr-Ni alloys (e.g., 316H stainless steel), ensuring long-term structural stability;
• The retained elongation (≥8%) at 800℃ prevents brittle fracture during emergency shutdowns or thermal shocks.

3. Application Products & Industry Scenarios

3.1 Aerospace Field

GH2132 is a core material for medium-temperature components in aero-engines and aerospace vehicles, with typical applications including:

• Aero-engine Components: High-pressure compressor disks (rotational speed up to 15,000 rpm), high-temperature fasteners (used in combustion chamber casings), and auxiliary power unit (APU) turbine disks. These parts operate in environments with 600-750℃ gas and cyclic thermal stress; the alloy’s creep resistance ensures a service life of up to 25,000 flight hours.
• Aerospace Structural Parts: High-temperature brackets and fluid pipeline connectors in environmental control systems (ECS), as well as thermal protection system (TPS) support structures. The alloy’s low density and good weldability simplify assembly and reduce aircraft weight.

3.2 Energy Field

3.2.1 Thermal Power Generation

In ultra-supercritical (USC) power plants (steam parameters: 600-620℃, 25-30MPa), GH2132 is used for:

• High-pressure Steam Valves: Gate valves and control valves in the main steam pipeline, resisting high-temperature steam erosion and ensuring seal integrity for over 100,000 hours.
• Boiler Headers: Medium-temperature headers (560-600℃) connecting superheaters and reheaters, where its thermal fatigue resistance reduces leakage risks caused by temperature fluctuations.
• Low-pressure Turbine Blades: Blades in the last two stages of turbines, where the alloy’s corrosion resistance (to low-sulfur steam) extends maintenance intervals by 18-24 months.

3.2.2 Industrial Gas Turbines

For gas turbines used in peak-shaving power plants or industrial drives (turbine inlet temperature: 1000-1100℃), the alloy is applied to:

• Compressor Impellers: High-pressure compressor impellers (stage 8-12), withstanding centrifugal forces up to 30,000g and 650℃ air temperature.
• Combustion Chamber Support Structures: Heat shields and bracket arms around combustion chambers, resisting radiant heat and cyclic thermal stress.

3.3 Petrochemical Field

In petrochemical plants (especially ethylene cracking and natural gas processing units), GH2132 is used for:

• High-temperature Centrifugal Compressor Disks: Disks in ethylene refrigeration compressors (operating temperature: 600-700℃, medium: hydrocarbon gas), where its creep resistance prevents disk deformation under long-term high-speed rotation (up to 12,000 rpm).
• High-pressure Valve Stems: Valve stems in hydrogenation reactors (pressure: 15-20MPa, temperature: 650-700℃), resisting hydrogen embrittlement and ensuring valve operation reliability.
• Catalyst Regeneration Furnace Components: Furnace tubes and support grids in catalyst regeneration systems, withstanding 750-800℃ flue gas and reducing maintenance costs by 30% compared to 310S stainless steel.
• Metallurgical Industry: High-temperature rolling mill work rolls for alloy steel hot rolling (working temperature: 700-780℃), and heat treatment furnace baskets (used for annealing high-strength alloys). The alloy’s wear resistance and oxidation resistance extend roll service life by 50% and reduce basket replacement frequency.
• Marine Engineering: High-temperature exhaust manifold components in large marine diesel engines (fuel: low-sulfur heavy oil), resisting combined corrosion from 600-650℃ exhaust gas and marine salt spray.
• High-temperature Test Equipment: Sample holders for medium-temperature creep testing (600-800℃) and medium-load fixture components in material performance testing machines, providing stable support for long-term tests (up to 5,000 hours).
• Hot Working: Forging temperature range: 1100-1180℃; avoid working below 950℃ to prevent grain boundary cracking;
• Cold Working: Cold rolling or stamping can be performed at room temperature, with intermediate annealing (900-950℃, 1h) recommended after 30-40% deformation to restore ductility;
• Heat Treatment: The standard two-step process (solid solution + aging) is critical—over-aging (above 750℃) will cause γ’ phase coarsening and strength degradation, while under-aging (below 680℃) will result in insufficient precipitation strengthening.

3.4 Metallurgical & Other Fields

4. Processing & Heat Treatment Recommendations

This comprehensive performance and application profile makes GH2132 a versatile and cost-effective superalloy for medium-temperature high-end manufacturing, balancing performance, processability, and economic efficiency.