Influence of shock wave in a liquid on the limited endurance of carbon steel

The effect of shock wave treatment in water on fatigue behavior of heat treated carbon steel is presented in the article. The carbon steel with 0.45 % of carbon was studied. Before being treated with shock wave the specimens were quenched and tempered at 300oC. Cyclic loading on symmetrical bending trials was performed. It was found that the shock wave treatment results inf hardness and fatigue strength of steel increase. The hardness increase derives from the growth of the total number of the crystal lattice defects. The increase of fatigue endurance is attributed to the moment of transition shift from reversible to irreversible damage up to the higher amplitude area accompanied by growth of cycles number before breakage. It is due to the improvement of steel structure resulting from the shock wave processing. It ensues from the mobile dislocations increased amount, which provides, through recombination, the subsequent increase of endurance in cyclic loading. As an additional source of the amount of mobile dislocations increase is the dislocations tear-out from fastening spots as a result of the shock wave treatment