Abstract
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.
