Surface Enhancement Application Notes
Low Plasticity Burnishing (LPB®) enhances foreign object damage (FOD) tolerance and improves fatigue performance of the leading and trailing edges of the LPC Stage 1 Blade in the F402-RR-408 engine used in the Harrier.
Gas Turbine Vane
Low Plasticity Burnishing (LPB®) improves foreign object damage (FOD) tolerance and high cycle fatigue endurance limits while completely mitigating cracking along the trailing edge of the Ti-6Al-4V Alloy F402 First Stage Low Pressure Compressor (LPC1)Vane used in the U.S. Marine Corps V/STOL tactical strike aircraft.
Gas Turbine Blade
Low Plasticity Burnishing (LPB®) mitigates pitting, diminishes foreign object damage (FOD), and improves damage tolerance and high cycle fatigue (HCF) while reducing the replacement costs of the 17-4 PH Stainless Steel 1st Stage Compressor Blade in the T56 Turboprop Engine.
Propeller Taper Bore
Low Plasticity Burnishing (LPB®) mitigates stress corrosion cracking (SCC) and improves corrosion fatigue strength while increasing the service life and reducing the total maintenance costs of the aluminum alloy 7076-T6 propeller for the U.S. Navy’s maritime patrol aircraft.
Low Plasticity Burnishing (LPB®) improves the damage tolerance of high-strength steel landing gear components through the development of an engineered residual stress distribution in the selected region to mitigate stress corrosion cracking (SCC) and fatigue failure.
Structural Aircraft Components
The US Navy and its foreign military sales partners are extending the service life of the P-3 Orion. Fleet aircraft are currently averaging approximately 24,000 flight hours, 16,500 hours past the designed service life. Full-scale pressurization testing showed that several forged floor beams are prone to fatigue damage due to stress concentrations from machined cutouts. Replacement of the components is impossible, so a program was implemented by NAVAIR to evaluate performance improvement by LPB®. LPB® treatment of P-3 Orion floor beams increases fatigue life and eliminates stress-related fractures.
Aging aircraft face numerous structural and component fatigue issues. Despite these ever-present challenges, due to economic standings and a lack of resources, aging aircraft must remain in service much longer than expected. Low Plasticity Burnishing (LPB®) can slow or entirely eliminate these problems.
Fatigue Design Diagram
The Fatigue Design Diagram (FDD) provides a means of designing compressive residual stress distributions into metallic components necessary to achieve optimal fatigue performance and to mitigate typical damage conditions.
Total Hip Prosthesis
300,000 hip replacement surgeries are performed in the United States each year. Modular hip prosthesis systems afford doctors the flexibility to choose properly sized components and treat a wide spectrum of patients. However, these replacements are vulnerable to fretting at their tapered connections. Every step taken by a patient represents a single loading and unloading cycle that accumulates over years of implantation. This damage can reduce the HCF life, and cause complete failure of the hip. LPB® treatment of high stress areas in prosthetic hips increases the fatigue life and eliminates the occurrence of failure from fretting-induced fracture.
Steam Turbine Blades
Steam turbines provide 80% of the world’s electricity, making them the backbone of power generation. Repeated exposure to high vibratory stresses and extreme steam environments leads to stress corrosion cracking (SCC) and fatigue failure in the turbine blades. Replacing damaged blades costs millions of dollars and can take months. The use of welding and identical replacement parts result in 50% of failures reoccurring. Low Plasticity Burnishing (LPB®) applies a deep, stable layer of compression in high stress areas of turbine blades to extend life and reduce costs.
Changes in national energy policy have caused temporary nuclear waste containment facilities to convert to long-term solutions. This makes the integrity of containment vessels a priority for storage facilities and power producers. SCC has plagued existing casks, impacting design life, safety and cost. By introducing a deep, stable layer of compressive residual stress, low plasticity burnishing (LPB®) has been proven to eliminate SCC in nuclear grade alloys, providing a permanent solution to the problem.
Oil and Gas
‘Sour’ environments in oil and gas recovery operations can severely limit the types of materials available for down-hole applications. Sulfide Stress Cracking (SSC), Stress Corrosion Cracking (SCC) and Hydrogen Embrittlement (HE) can prevent the use of common high strength steel alloys. The current method to mitigate cracking is to use more expensive alloys with increased corrosion resistance. Low plasticity burnishing (LPB®) provides a different approach. By introducing a deep, stable layer of compressive residual stress, LPB® has been shown to eliminate SSC in high strength steels, providing a cost-effective solution to the problem.