Airfoil Cover Attachment via Friction Stud Welding

The patent replaces traditional high-temperature fusion welding with a hybrid joining system that uses friction stud welds (mechanical friction-based joining) as the primary attachment method. This mechanical substitution achieves strong joints at lower temperatures compared to conventional welding, reducing thermal damage risks while maintaining joint strength. The friction-based mechanism generates localized heat only at the contact interface, rather than heating the entire workpiece.

The patent changes the joining parameters from high-temperature fusion welding to a multi-parameter system involving friction stud welds at optimized temperature and pressure conditions. By controlling the friction welding parameters (temperature, pressure, time) and combining them with braze filler material application, the process achieves strong joints while maintaining lower overall manufacturing temperatures and reducing thermal stress on the airfoil structure.

The patent employs a composite material system for cover attachment: friction stud welds provide structural bonding, braze filler material provides sealing and metallurgical bonding, and protective filler materials (anti-corrosion and anti-erosion compounds) provide environmental protection. This composite approach combines multiple materials with complementary properties, achieving both weight reduction through the hollow cover structure and enhanced corrosion resistance through the multi-layer protective system.

The patent applies protective filler materials (anti-corrosion and anti-erosion compounds) to the joint area between the cover and airfoil body before the component enters service. This beforehand cushioning protects the joint from corrosive and erosive environments that would otherwise degrade the connection over time, ensuring long-term reliability and durability of the cover attachment in the harsh gas turbine operating environment.