Enhanced Fatigue Resistance
Laser peening emerged as a necessary application for parts requiring greater fatigue enhancement than shot peening could provide. Improvements in fatigue life and fatigue strength are proportional to the magnitude and depth of induced compressive residual stresses present within a component. Sometimes the shot peening intensity is insufficient to generate high enough compressive residual stresses, while other times the depth of the compressive stress profile is too shallow for critical parts. Laser peening routinely produces compressive residual stresses ten times deeper than those achieved via shot peening, providing unrivaled fatigue life extentions while improving safety and reliability.
The first use of production laser peening was to provide fatigue cracking resistance to turbine engine components used by the U.S. Air Force. The shallow residual stresses generated by shot peening (typically around 0.005 inch deep) were insufficient for preventing engine failures that endangered aircraft and crew. When laser peening was applied to the titanium fan blades, the deep compressive residual stresses inhibited cracking associated with foreign object damage (FOD), saving the DoD millions of dollars in inspection, maintanence, and repair costs while ensuring pilot safety. For more information on this application, read our success story on the B-1 bomber.
Since its initial application in aircraft engines, laser peening has proven to be more effective than shot peening at increasing fatigue life for parts across a variety of industries. Due to the superior compressive residual stress profiles afforded by laser peening, customers in the aerospace, automotive, manufacturing, and industrial sectors have incorporated LSP into their manufacturing processes. The potential cost savings and benefits of increasing component lifetimes extend far beyond the value of the part itself:
- Reduced downtime
- Reduced labor costs
- Reduced material costs
- Reduced manufacturing costs
- Increased safety
- Increased readiness/capability
- Improved reputation
- Increased sales
Laser peening has been shown to provide over 10x life increases for components that had previously only been shot peened. This type of service life extension is unparalleled among surface enhancements, and has the power to revolutionize many industry practices. Not only will laser peened parts last longer, but they can be manufactured with less material to reduce costs and improve efficiency.
Beyond enhanced fatigue resistance and service life, laser peening has proven superior to shot peening across a number of performance-related applications:
- Retains compressive residual stresses to higher temperatures
- Reducing crack growth rates (da/dN)
- Improving life of welded components
- Improved fretting damage resistance
- Improved galling resistance
- Improved spallation resistance
- Improved stress corrosion (SCC) resistance
Laser peening consistently outperforms shot peening when it comes to the material enhancement properties associated with compressive residual stresses. Check out the LSPT Library to browse a collection of free technical papers, or contact us to learn how laser peening can improve the performance of your critical parts..