A fractographic study exploring the fracture surface topography of S355J2 steel after pseudo-random bending-torsion fatigue tests

•The effect of the fatigue loading on the fracture surface of S355J2 steel is demonstrated.•Surface parameters in the context of the description of the fatigue fracture scenarios are discussed.•Fracture topography are evaluated for the total fracture areas. This paper presents the influence of multiaxial loading and fatigue behavior on a fracture surface in the context of its topography. For analysis were taken fracture surfaces obtained in experimental tests of S355J2 steel subjected to non-proportional bending with torsion. A high-resolution optical 3D profilometer was used in the examination and surface measurements. For a quantitative description of fracture mean surface roughness parameter Sa and a fractal dimension Df were employed. Surface topography studies were carried out on the entire fracture surface. Shear stress contribution expressed through ratio of maximum stresses λ, loading conditions represented by variance of normal and shear stress µ, and fatigue life influence on the fracture surface parameters were found. Such a method of applying advanced way of topography application is useful not only as a measurement methodology but also, as innovation method of surface evaluation.