GH2901 Alloy
Short Description:
GH2901 Alloy GH2901 is a high-performance iron-nickel-cobalt (Fe-Ni-Co) based precipitation-hardening wrought superalloy, specifically designed for medium-to-high temperature service scenarios requiring exceptional creep resistance, thermal stability, and resistance to harsh corrosive media. It achieves strengthening primarily through the coherent precipitation of high-stability γ’ phase (Ni₃Al, Ti, Nb) — with a γ’ phase content of approximately 18-23% — and is supplemented by sy...
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GH2901 Alloy
GH2901 is a high-performance iron-nickel-cobalt (Fe-Ni-Co) based precipitation-hardening wrought superalloy, specifically designed for medium-to-high temperature service scenarios requiring exceptional creep resistance, thermal stability, and resistance to harsh corrosive media. It achieves strengthening primarily through the coherent precipitation of high-stability γ’ phase (Ni₃Al, Ti, Nb) — with a γ’ phase content of approximately 18-23% — and is supplemented by synergistic solid solution strengthening from chromium (Cr) and molybdenum (Mo). Unlike Fe-Ni-Cr based GH91 (focused on sulfur corrosion resistance), GH2901 incorporates cobalt to enhance matrix stability and high-temperature strength, enabling reliable long-term operation in harsh conditions ranging from 680℃ to 900℃.
Notably, GH2901 forms a dense, multi-layer protective oxide film (Cr₂O₃-Al₂O₃-Nb₂O₅) at high temperatures, providing superior resistance to sulfur-containing flue gas, high-pressure steam, and molten salt corrosion. It retains excellent hot workability and weldability, making it suitable for manufacturing large-scale complex load-bearing components (e.g., industrial gas turbine disks, thermal power plant high-pressure headers). It is widely used in advanced thermal power generation, industrial gas turbines, and petrochemical industries, where material performance under medium-to-high temperature thermal-mechanical coupling conditions is critical. The following is a comprehensive breakdown of its chemical composition, physical properties, and application products.
1. Chemical Composition (Mass Fraction, %)
| Element | Carbon (C) | Chromium (Cr) | Nickel (Ni) | Cobalt (Co) | Molybdenum (Mo) | Titanium (Ti) | Aluminum (Al) | Niobium (Nb) | Iron (Fe) | Manganese (Mn) | Silicon (Si) | Phosphorus (P) | Sulfur (S) | Boron (B) | Zirconium (Zr) |
| Content Range | ≤0.08 | 18.0-21.0 | 33.0-37.0 | 9.0-11.0 | 4.5-5.5 | 2.3-2.8 | 0.3-0.8 | 0.7-1.2 | Balance | ≤0.50 | ≤0.50 | ≤0.015 | ≤0.010 | ≤0.010 | ≤0.10 |
| Function Note | Precisely controls grain growth; forms fine MC carbides at grain boundaries to enhance intergranular strength and creep resistance | Enhances high-temperature oxidation and thermal corrosion resistance; forms Cr₂O₃ protective film to isolate corrosive media | Forms stable γ’ phase with Ti/Al/Nb; ensures alloy ductility and toughness at 680-900℃ | Improves matrix stability; raises alloy recrystallization temperature and enhances high-temperature strength | Enhances medium-to-high temperature (700-850℃) strength; improves resistance to hydrogen embrittlement in petrochemical environments | Core element for γ’ phase precipitation; determines γ’ phase content and high-temperature creep resistance | Assists Ti in forming γ’ phase; optimizes γ’ particle size (0.1-0.2μm) for balanced strength and ductility | Enhances γ’ phase stability; raises γ’ solvus temperature to 950℃, extending service temperature range | Matrix element; balances alloy cost, density, and processability for large components | Improves hot workability; strictly controlled to avoid low-melting-point inclusions | Enhances deoxidation effect; strictly limited to avoid reducing high-temperature mechanical properties | Strictly limited to prevent intergranular corrosion in sulfur-containing/high-pressure steam environments | Strictly limited to avoid hot cracking during forging/welding; refines grain boundaries | Refines grain boundaries; improves intergranular strength and thermal fatigue resistance |
2. Physical Properties
2.1 Basic Physical Parameters
- Density: Approximately 8.10g/cm³ at room temperature (25℃), slightly higher than Fe-Ni-Cr based GH91 (7.95g/cm³) due to Co addition, but 7-9% lower than high-Ni superalloys such as GH4738 (8.45g/cm³). This low-density advantage is critical for weight-sensitive medium-to-high temperature load-bearing components (e.g., industrial gas turbine disks), reducing equipment overall weight by 3-8% compared to high-alloyed alternatives like Inconel 718.
- Magnetic Properties: Weakly magnetic at room temperature (magnetic permeability μᵣ ≈ 1.006-1.013); magnetic property gradually fades as temperature rises, becoming nearly non-magnetic (μᵣ ≈ 1.002-1.003) in the service temperature range (680-900℃). This makes it suitable for applications near general electromagnetic equipment, though caution is needed for high-precision magnetic sensors (e.g., gas turbine speed sensors).
- Melting Temperature Range: 1340-1400℃ (liquidus: ~1400℃; solidus: ~1340℃). The narrow and stable melting range ensures uniform solidification during casting and consistent deformation during forging, reducing internal defects (e.g., shrinkage porosity, segregation) and improving structural integrity—critical for high-stress medium-to-high temperature parts like turbine disks.
- Thermal Expansion Coefficient (CTE):
2.2 Thermal Properties
◦ 20-100℃: ~12.3×10⁻⁶/℃
◦ 20-600℃: ~13.8×10⁻⁶/℃
◦ 20-800℃: ~15.1×10⁻⁶/℃
◦ 20-900℃: ~15.5×10⁻⁶/℃
The gradual CTE increase minimizes thermal stress during frequent temperature cycling (e.g., gas turbine start-stop, boiler load adjustment), reducing thermal fatigue cracking risk by 50-60% compared to Fe-Cr-Ni alloys like GH91.
- Thermal Conductivity (λ):
◦ 100℃: ~15.5W/(m·K)
◦ 500℃: ~18.8W/(m·K)
◦ 800℃: ~22.2W/(m·K)
◦ 900℃: ~22.9W/(m·K)
The temperature-dependent conductivity improvement promotes efficient heat dissipation in medium-to-high temperature components, avoiding localized overheating (a major cause of creep acceleration) and extending part service life by 35-40% compared to GH91.
2.3 Mechanical Properties (After Standard Heat Treatment: 1100-1140℃ solid solution for 1h, water cooling + 740-770℃ aging for 10h, air cooling)
| Property | Room Temperature (25℃) | 680℃ | 780℃ | 850℃ | 900℃ |
| Yield Strength (σ₀.₂, MPa) | ≥750 | ≥680 | ≥600 | ≥450 | ≥360 |
| Tensile Strength (σᵦ, MPa) | ≥950 | ≥880 | ≥780 | ≥580 | ≥480 |
| Elongation (δ₅, %) | ≥18 | ≥16 | ≥14 | ≥12 | ≥10 |
| Reduction of Area (ψ, %) | ≥25 | ≥23 | ≥21 | ≥18 | ≥15 |
| Creep Rupture Strength (1000h, MPa) | - | ≥520 | ≥420 | ≥280 | ≥200 |
Key Notes:
- The high room-temperature strength (σᵦ ≥950MPa) meets the load-bearing requirements of industrial gas turbine disks and thermal power plant high-pressure valves, with strength 3-5% higher than GH91;
- At 780℃ (a typical service temperature for petrochemical cracking furnace internals), the creep rupture strength (≥420MPa) is 5-8% higher than that of GH91, ensuring long-term structural stability under medium-to-high temperature load;
- Even at 900℃ (near its upper service limit), the retained elongation (≥10%) prevents brittle fracture during emergency shutdowns, making it suitable for components with frequent thermal cycling (e.g., metallurgical furnace rolls, gas turbine combustion chamber supports).
3. Application Products & Industry Scenarios
3.1 Industrial Gas Turbine Field
As a core material for medium-to-high temperature components in industrial gas turbines, GH2901 is used for:
- Gas Turbine Disks: Medium-pressure turbine disks (rotational speed up to 18,000 rpm) in combined cycle power generation turbines, operating in 750-850℃ high-temperature gas environments; the alloy’s creep resistance ensures a service life of up to 120,000 hours;
- Combustion Chamber Supports: High-temperature support rings and brackets around combustion chambers, withstanding 800-850℃ radiant heat and cyclic thermal stress; its thermal stability reduces deformation risks by 40-50% compared to GH91;
- Turbine Blades (Low-Pressure Stages): Blades in the last 2-3 stages of turbines, withstanding 680-750℃ gas erosion and centrifugal forces; its low density reduces turbine rotational inertia and energy consumption.
3.2 Advanced Thermal Power Generation Field
In ultra-supercritical (USC) thermal power plants (steam parameters: 620-650℃, 30-35MPa), GH2901 is applied to:
- High-pressure Boiler Headers: Headers connecting final superheaters (operating temperature: 680-720℃), where its excellent weldability allows for large-diameter header manufacturing (maximum diameter ≥1400mm) without welding defects;
- Steam Turbine Rotor Parts: Rotor shafts and disks in high-pressure turbines, withstanding 650-700℃ high-pressure steam and cyclic thermal stress; the alloy’s creep resistance extends maintenance intervals by 30-36 months compared to 12Cr1MoV steel;
- Superheater Tube Supports: Support structures for superheater tubes, resisting 700-750℃ steam oxidation and mechanical wear.
3.3 Petrochemical Field
In large-scale petrochemical and coal-to-olefins units (operating temperature: 750-880℃), GH2901 is used for:
- Cracking Furnace Tubes & Liners: Core furnace tubes and inner liners in coal-to-olefins cracking furnaces, resisting hydrocarbon gas pyrolysis corrosion and high-temperature sulfur-containing media; compared to GH91, it extends service life by 55-65% and reduces maintenance costs by 45-50%;
- High-pressure Hydrogenation Reactor Internals: Catalyst support grids and valve stems in heavy oil hydrogenation reactors (pressure: 22-28MPa, temperature: 800-850℃), resisting hydrogen embrittlement and sulfur corrosion;
- Waste Heat Boiler Tubes: Tubes in petrochemical waste heat recovery boilers, resisting 780-830℃ flue gas corrosion and improving heat recovery efficiency by 20-25%.
- Metallurgical Industry: High-temperature furnace rolls (working temperature: 780-880℃) for stainless steel continuous annealing lines, withstanding high-temperature air oxidation and metal melt splashing; the alloy’s wear resistance extends roll service life by 75-85% compared to 310S stainless steel;
- Vacuum Heat Treatment Equipment: Heating element supports and furnace liners in ultra-high-temperature vacuum annealing furnaces (operating temperature: 850-900℃), ensuring uniform temperature distribution and avoiding contamination of heat-treated workpieces (e.g., high-precision superalloy components);
- High-temperature Test Equipment: Sample holders for medium-to-high temperature creep testing (680-900℃) and high-load fixture components in material performance testing machines, providing stable support for long-term tests (up to 10,000 hours) and ensuring accurate test data for superalloy research.
- Hot Working: Forging temperature range: 1140-1200℃; initial forging temperature should not exceed 1200℃ to avoid γ’ phase dissolution and grain coarsening, and final forging temperature should not be lower than 1000℃ to prevent work hardening and cracking;
- Cold Working: Cold working is limited to light deformation (≤15%) such as precision machining and grinding; cold rolling or stamping is not recommended due to high room-temperature strength; intermediate annealing (1040-1080℃, 1h) is required after any cold deformation to restore ductility;
- Heat Treatment: The two-step process (solid solution + aging) must be strictly controlled—over-aging (above 800℃) will cause γ’ phase coarsening (particle size >0.4μm) and significant strength degradation, while under-aging (below 720℃) will result in insufficient precipitation strengthening and reduced high-temperature creep resistance.
3.4 Metallurgical & Other High-temperature Fields
4. Processing & Heat Treatment Recommendations
This comprehensive performance and application profile makes GH2901 an advanced, cost-effective superalloy for medium-to-high temperature high-end manufacturing, perfectly balancing thermal corrosion resistance, high-temperature strength, and processability for large-scale, complex-shaped components in industrial gas turbines, power generation, and petrochemical industries.
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