Effect of Texture and Microstructure on Resistance to Cracking of High-Strength Hot-Rolled Nb-Ti Microalloyed Steels

摘要

Significant texture gradient in the through-thickness direction was observed in high-strength hot-rolled 560 and 770 MPa Nb-Ti microalloyed steels, characterized by polygonal fertile and fertile bainite microstructures, respectively. {113}<110> was the most intense deformation texture in the two high-strength grades of Nb-Ti steels and was dominant in the midthickness region compared to 10 and 25 pct depth below the surface. The recrystallization texture of austenite, {100}<001>, transformed into {100}<011> component in the ferrite and indicated an increase in the intensity with increase in depth for the Nb-Ti microalloyed steels. The (100}<011> texture has a detrimental effect on the edge formabiity of steels. However, the midthickness plane contained considerable intensity of desired texture, {332}<113>, which is expected to offset the undesirable {100}<011> texture resulting in superior edge formability and impact toughness of Nb-Ti steels, consistent with experimental observations.