Aerospace Fuel Delivery Forging Machining

Aerospace fuel delivery forging machining refers to the manufacturing of critical metal parts for aircraft engines, rocket propulsion systems, or satellite fuel supply systems through forging processes combined with precision machining. These components are primarily used to transport fuels such as aviation kerosene, liquid hydrogen/liquid oxygen, ensuring reliability and safety in high-altitude, high-speed, extreme temperature (-200°C to +500°C), and high-pressure (>10 MPa) environments. Forging processes (such as die forging or precision forging) provide excellent grain refinement, strength, and defect-free structure. Compared to casting or machining, forged parts can have a 2-5 times longer fatigue life, making them suitable for the high reliability requirements of aerospace applications (compliant with AS9100 standards). Typical components include fuel pump housings, valve bodies, nozzle connectors, and pipeline flanges.

1. Material Properties

High-performance alloys are commonly used for aerospace fuel delivery forgings to ensure corrosion resistance, high-temperature resistance, and lightweight properties:

• Titanium Alloy (Ti-6Al-4V): Lightweight (density 4.5 g/cm³), high strength (>900 MPa), and resistant to fuel corrosion, suitable for low-temperature liquid hydrogen systems.
• Nickel-Based Superalloys (Inconel 718, Hastelloy X): Resistant to high temperatures (>1000°C) and oxidation, suitable for high-temperature gas turbine fuel delivery.
• Stainless Steel (17-4PH, 15-5PH): Precipitation-hardened, hardness HRC>40, fatigue-resistant, suitable for medium-temperature aviation kerosene systems.
• Other: Aluminum alloy (7075-T6) for lightly loaded components, or cobalt-based alloys for extreme wear resistance applications.

2. Processing Methods

Forging machining combines rough forging, heat treatment, and finishing to ensure accuracy (tolerance ±0.02mm) and surface quality (Ra≤0.8μm). Key steps include:

• Closed-Die Forging: Using high-temperature molds (800-1200°C) to forge the billet, forming near-net-shape parts. Advantages: Material utilization rate >90%, reducing machining volume. Suitable for complex shapes such as pump body cavities.
• Isothermal Forging: Forging at a constant temperature in a vacuum or inert gas environment, suitable for titanium/nickel alloys, avoiding oxidation and deformation. High precision and uniform grain size.
• Heat Treatment: Vacuum quenching + age hardening to increase strength (e.g., Inconel 718 hardness increases from HRC 30 to 45).
• Finishing:
  • 5-Axis CNC Machining: Removing excess material, machining curved surfaces and hole systems. Using high-rigidity machine tools (such as DMG Mori), combined with CAM software to optimize paths and control vibration <5μm.
  • Electrochemical Machining (ECM) or Laser Machining: Non-contact finishing of internal cavities, avoiding thermal stress, surface roughness Ra<0.4μm.
  • Grinding/Polishing: Final surface treatment to improve corrosion resistance.
• Auxiliary Processes: Non-destructive testing (ultrasonic/X-ray) to ensure no cracks; surface coatings (such as DLC or ceramic coatings) to enhance wear resistance.