Font Size: 

The aim of this paper is to provide the results of own researches into freeshort fatigue crack initiation and growth in residual stress field induced by surface laserhardening or by shot peening. Comparable study was carried out primary for non-treatedmedium carbon steel specimens in air and at room temperature. The high cycle fatigue testswere conducted under fully reversed torsion for smooth both non-treated and treatedspecimens. The paper consists of two parts: first part presents the experimental results ofthese studies whereas the second one derives the proposition of short crack growth descriptionin the aspect of probabilistic approach.