Axial Force Behaviors of High-strength Bolt Treated by High Power CW Leaser

— In this study, the axial force loss of high-strength bolt after 3kW CW-laser treatment was examined. High-strength bolt specimens were prepared, and a hand-held laser transmitter was irradiated on the bolt head with CW-laser power of 3kW. The change in the axial force on the bolts was examined during the bolt's treatment based on the irradiate duration on the bolt surface. Axial force loss of the bolts was affected by the irradiation duration and position. With multiple irradiations on the bolt head, the axial force loss reduced compared with the same irradiation time was confirmed. From the relationship between the axial force change and the treatment duration, axial force loss equations of bolt side laser treatment were suggested based on multiple round irradiations, which can help estimate the axial force loss and make the maintenance plan.