Effect of microstructure and crystallographic texture on the toughness anisotropy of API 5L X46 STEEL

The combined effect of microstructure and crystallographic texture on the toughness anisotropy of API 5L X46 steel was studied. The steel exhibited microstructural banding along the 0° direction and near random texture in the material. The mechanical properties were characterized by the use of tensile and impact toughness samples oriented along the rolling direction (0°, 45°, and 90°). For impact toughness, anisotropic behavior was observed, where the 0° oriented samples showed lower impact toughness than the 90° and 45° directions, with differences of 25% and 31%, respectively, while the yield strength (YS) showed the lowest values in the 0° oriented samples. The relative variation coefficient (r_rv) indicates significant correlation between microstructure, texture, and toughness anisotropy. It was observed that the banding degree and the amount of {110} and {111} oriented grains are directly related to the degree of anisotropy, which high values are the cause of lower mechanical properties.