Effect of Laser Shock Processing Residual Stress on Pellet Traveling Grate Surface Crack

Abstract

The effect of the laser shock processing on Pellet Traveling Grate surface fatigue crack growth performance were investigated from the theory of the fracture mechanics.A stress formula was set up to indicate the function of the residual stress on fatigue life. The effect of the compressive stresses was deemed responsible for increasing the resistance to fatigue crack growth of the Pellet Traveling Grate.It was observed that the dynamic stress intensity factor of the crack and the stress ratio were declined due to laser shock processing, which would make the spread doorsill of the fatigue crack increasing. The results indicate a significant reduction in fatigue crack growth rates using laser shock processning specimens.It is shown that the near-surface microstructures, which in Pellet Traveling Grate consist of a layer of work hardened nanoscale grains, play a critical role in the enhancement of fatigue life by mechanical surface treatment.