Anisotropy in Microalloyed S355N Steel

Thermomechanical control process steel produced by rolling has a significant anisotropy. The elongated grains and inclusions formed during hot rolling of ferrite and low carbon HSLA steels directly influence the anisotropy of the steel’s mechanical properties as a result of microstructural anisotropy. The present research deals with this anisotropy, and particular attention has been paid to the tensile and Charpy V-notched behavior and microscopic properties. The mechanical response of a 25 mm thick rolled plate of S355N steel was characterized. The results of Charpy tests of V-notched specimens of the through-thickness direction were found to be considerably temperature-dependent and also to vary in the longitudinal and the transverse directions. Marked anisotropy effects were observed, with the through-thickness orientation exhibiting a tensile response lower than that of the longitudinal and transverse ones. These experimental findings were rationalized using the correlation holding among inclusion distribution, reduction area percent, and banding of the microstructure.