摘要:Static mechanical, dynamic and resistance to cy-clic loading properties obtained for differently heat-treated low carbon steel AISI 4130. Insignificant change of chem-ical content and heat-treatment change hardness, strength, ductility properties, impact resistance and threshold value of fatigue crack propagation. An analysis of CT speci-mens’ fractured views performed using SEM shows rela-tionship of material microstructure with cyclic fracture.