Improving Fatigue Lives of Welding Joints Due to Laser Peening under Low Pulse Energy Condition

Laser peening can introduce compressive residual stress on the surface of various materials and, therefore, is effective in enhancing the fatigue strength. This study clarifies whether the laser peening with lower pulse energy comparing to the preceding studies generates compressive residual stress, and whether such stress would account for prolonged fatigue life in the welded zone of high-strength steel HT780. Moreover, configuration and effect of a newly-developed portable laser peening device are introduced.