Fatigue behavior of plain C-Mn steel plates with fine grained ferrite in surface layers

► Grain refinement can improve effectively the fatigue properties of C-Mn steel plates. ► The area of fatigue striations in plate with fine grained ferrite is less than that with coarse grained ferrite. ► The ferrite grain refinement in the surface layers of the steel plates can hold back or postpone the formation of surface fatigue cracks. ► The banding pearlite can promote the formation and extension of the secondary cracks.