Short fatigue crack growth in laser hardened medium carbon steel

Short fatigue crack behaviour in laser hardened medium carbon steel (0.45%C) smooth specimens subjected to reversed torsion (R=1) was investigated. The plots of crack length distribution, crack growth and crack growth respectively rate versus number of cycles were presented. Characteristic features of a mechanism of cracking in specimens with various laser track geometry were established on the basis of observations made through SEM and TEM.