Texture and mechanical properties of API X100 steel manufactured under various thermomechanical cycles

The role of various finishing rolling operations on the texture and mechanical properties has been studied for API (American Petroleum Institute) X100 steel. It has been found that both the finish rolling start and end temperatures influence the final texture and thus, the mechanical properties and the anisotropy of these properties. High temperature finish rolling produces a very weak texture. This texture is a result of dynamic recrystallization, and associated with large grain size and inferior mechanical properties. A slightly delayed start of accelerated cooling led to the formation of large fraction of polygonal ferrite and increased the ductility at the expense of strength. Near-isothermal rolling in the range of 790–810 °C produced the highest texture intensities of both the desired {3 3 2}〈1 1 3〉 and the undesired {1 1 3}〈1 1 0〉 components. The latter texture components as well as the {1 0 0}〈1 1 0〉 component, mitigated the positive effect of the {3 3 2}〈1 1 3〉 component. On the other hand, a relatively higher finish rolling start temperature (840 °C) and a low finish rolling end temperature (700 °C) suppressed the strength of the {1 1 3}〈1 1 0〉 and {1 0 0}〈1 1 0〉 components, while the {3 3 2}〈1 1 3〉 component apparently was sufficient for the reduction of the anisotropy of mechanical properties. Partial deformation of the quasi-polygonal ferrites also appeared to have contributed to increasing the strength of the investigated steel.