1. Specifications & Capability
FUSHUN METAL forges turbine and compressor discs in AISI 4340 high-strength steel and precipitation-hardening nickel alloys such as Inconel 718 (UNS N07718), to custom sizes for gas turbine and aerospace applications. Discs are produced by open-die forging and, for the nickel alloys, isothermal forging to control grain size and maximise mechanical properties.
The forging ratio is at least 4:1, with radial grain flow to carry the centrifugal load. Every disc receives full-section ultrasonic testing and is supplied to aerospace-grade traceability.
| Grade | Standard | Typical Use |
|---|---|---|
| AISI 4340 | SAE J404 / AMS | Compressor discs, lower-temperature stages |
| Inconel 718 (N07718) | AMS 5662 | Turbine discs, high-temperature stages |
2. Components & Service Conditions
These forgings are the turbine and compressor discs of gas turbines and aero-engines, carrying the blading against the full centrifugal load while exposed to their respective temperature regimes. Compressor discs run comparatively cool and use high-strength AISI 4340, while turbine discs face combustion temperatures and use Inconel 718 for its strength retention up to about 650 C.
The disc bore sees the highest hoop stress, so soundness and grain size at the hub are the controlling requirements. Forging with radial grain flow, plus full-section ultrasonic testing, gives the homogeneous structure that aerospace standards demand, and the nickel-alloy discs are isothermally forged to keep grain size fine for maximum fatigue strength.
3. Grade Equivalents – AISI 4340 / Inconel 718
| Designation | Standard | Notes |
|---|---|---|
| AISI 4340 | SAE J404 | High-strength low-alloy steel |
| Inconel 718 / N07718 | AMS 5662 | Precipitation-hardening nickel alloy |
| Waspaloy / N07001 | AMS 5707 | Higher-temperature nickel alloy option |
| 40CrNiMoA | GB/T 3077 | Reference only, not used in certification |
| Grade | C | Cr | Ni | Mo | Nb+Ta | Ti | Al |
|---|---|---|---|---|---|---|---|
| Inconel 718 (N07718) | 0.08 max | 17.0-21.0 | 50.0-55.0 | 2.8-3.3 | 4.75-5.50 | 0.65-1.15 | 0.20-0.80 |
| AISI 4340 | 0.38-0.43 | 0.70-0.90 | 1.65-2.00 | 0.20-0.30 | – | – | – |
The niobium-titanium-aluminium additions give Inconel 718 its precipitation hardening, retaining strength up to about 650 C for turbine disc service.
4. Manufacturing Process
Steelmaking. FUSHUN METAL produces the nickel alloys to aerospace cleanliness limits, with vacuum induction melting or vacuum arc remelting to remove inclusions and secure fatigue life.
Forging. Steel discs are open-die forged; nickel-alloy discs are isothermally forged to keep grain size fine and uniform for maximum fatigue strength.
Heat treatment. AISI 4340 is quenched and tempered; Inconel 718 is solution treated and precipitation hardened to the ordered condition.
Testing. Full-section UT to aerospace acceptance, MT, and mechanical tests, with aerospace-grade traceability.
5. Standards & Certification
Turbine and compressor discs are supplied to AMS and aerospace engine specifications, with inspection certificates under EN 10204 3.1 and optional 3.2 third-party inspection. FUSHUN METAL holds ISO 9001 and AS9120B certification.
Related forging: turbine discs and wheels.
6. Typical Applications
Gas turbines
Turbine and compressor discs for industrial gas turbines.
Aero-engines
Discs for aircraft gas turbine engines.
Compressor stages
High-strength AISI 4340 compressor discs.
Turbine stages
Inconel 718 turbine discs for hot sections.
7. Inquiry Essentials
To quote your turbine or compressor disc, please provide the disc drawing, the temperature and stress loading, the required material specification, and the ultrasonic testing acceptance level.
