Very high cycle fatigue tests of high strength steels S355 J0 and S355 J2

Abstract The high strength steel S355 is frequently used in civil engineering to design bridges, its elements or simple engineering parts. The properties of the steel lead to savings both material’s and economical meeting strict construction requirements. From this reason, fatigue resistance of the material is in focus of researchers. Results obtained from experimental observations provide reliable inputs to lifetime assessments and numerical simulations of fatigue loaded structures like bridges, cranes and other constructions. As these constructions are designed for a long life, we have studied the properties of the material in the field of high-cycle and very high-cycle fatigue. Tests of two standard S355 J0 and S355 J2 steel grades were performed on ultrasonic fatigue testing system. Both steels exhibited fatigue behavior in gigacycle region while S355 J2 exhibited higher number of cycles to failure. Fracture surfaces were studied and showed both surface and subsurface crack initiation.