This study researches how stress concentration has an effect on cyclic behavior of H-shaped beam with web perforation made of high strength steel “H-SA700”. It is examined and compared with the same shaped beam made of “SN400” by cyclic loading tests. Cyclic elastic deformation of H-SA700 increases even under constant-amplitude cyclic loading. This property may amplify the local plasticity near a circular hole. So new yield strength, Qc and QF, by means of elastic theory of stress concentration, are suggested. Qc is a minimum strength when somewehre in a hole edge will be plastic. Similarly QF is a minimum strength in a minimum section. In addition large deformation behavior of H-SA700 is shown.
