Crystallographic Texture Effect on the Anisotropic Behavior of the Fatigue Endurance of API 5L X42 Pipeline Steel

The crystallographic texture effect on fatigue endurance anisotropic behavior was evaluated for an API 5L X42 pipeline steel among longitudinal (L-0°), diagonal (D-45°), and circumferential (C-90°) directions. Results showed that the strongest direction was the C-90° direction, which presented the lowest degree of banding (Ai) and grain orientation (Ω12), as well as a larger number of grains oriented parallel to {110} planes. Therefore, fatigue life anisotropy is mainly controlled by the synergistic interaction between pearlite banding degree (Ai) and crystallographic texture. Also, it is foreseen that the observed behavior can be related to the dislocation arrays generated by cyclic loading in relation to microstructure orientation.