Experimental research on the effects of different overlapping rate in laser shock processing

The Samples of a kind of martensite stainless steel treated by LSP with different overlapping rate of laser shock spot were used to study the effects of overlapping rate. The surface residual stress and microhardness of the laser shock zone as well as the fatigue life of the samples with different overlapping rate were tested. The results show that: with the increasing overlapping rate, the overlap interspaces between the practical shock notches on samples reduces. Meanwhile, the fluctuation of residual stress and microhardness is significantly decreased. And the fatigue life of the samples is increased. So the conclusion is drawn that increasing overlapping rate can decrease the overlap interspaces, which optimize the distribution of the residual stress and the microhardness around the shock notches, and consequently improve the fatigue life.