Fatigue crack Propagation in flat 18G2A and St3SY steel welded specimens

This paper confirms that at welded cyclic loaded specimens greater fatigue life is usualy met for those made of low strength steel rather than for those made of material revealing higher mechanical properties. Numerical investigation results also show a confirmation of this thesis, when tests are carried out on flat 18G2A and St3SY steel specimens butt welded single, overloaded every Delta N cycles and at k_ov=1.75. The experimental results of those specimens have showed an approximately 80% higher fatigue life for St3SY steel.