Effect of laser shock peening uniformity on bending fatigue life of 20CrNiMo

In order to improve the effect of laser shock peening, the factors affecting the uniformity of laser shock peening and its influence on the bending fatigue life of specimens were investigated by combining experiment and simulation. The results show: overlap rate, energy, laser pulse time and spot diameter are the influencing factors of laser shock peening, among which overlap rate is the most important factor affecting laser shock peening uniformity. Laser shock peening uniformity improves the flexural fatigue life of the specimen. When the laser energy density is similar, better uniformity of the laser shock peening leads to higher fatigue life, and better uniformity compensates for the difference in laser energy density. When the overlap rate is 62.5 %, the energy is 6 J, the laser pulse time is 20 ns, and the spot diameter is 3 mm, the laser shock peening uniformity is better, and the bending fatigue life of the specimen is improved by a factor of 5.41 compared with the unimpacted specimen. The study of the uniformity of laser shock peening intensification has important implications for the selection of the laser shock process parameters.