The development of inhomogeneity in the microstructure, texture, and mechanical property in hot-rolled (API) 5L X70 pipeline steel after rough and finish thermomechanical control processing has been investigated by experimental measurements. Our investigations revealed that the rough rolling stage produced mostly large and coarse ferrite grains across the thickness, while the finish rolling stage led to a rather refined small-grained microstructure. EBSD investigations confirmed that after the rough rolling stage, recovered and deformed grains dominated the quarter and mid-thickness compared to the surface. Investigation of the finish rolled steel showed that in comparison with the quarter and mid-thickness sections of the plate, the surface section mostly consists of deformed grains. The texture components obtained from x-ray measurement showed that after rough and finish processing stages, the {001} <100>, {110} <112>, {123} <634>, {112} <111>, and {001} <110> components were observed to be present. However, inhomogeneity of texture was observed at different depths of the rolled steel, such that in comparison with the surface, volume fractions of texture and intensities of the desired γ-fiber texture were seen to be highest at the mid- and quarter-thickness sections after both rolling stages. The room-temperature tensile stress–strain curves showed that the highest yield strength was observed for samples obtained from the near-surface section, while samples obtained from the mid-thickness section showed the highest elongation during tensile deformation. Overall, the final stage processing was observed to refine the final microstructure of the steel, thus improving the strength of the steel.

通过实验测量研究了粗轧和精轧热机械控制处理后热轧（API）5L X70管线钢的组织，织构和力学性能的不均匀性。我们的研究表明，粗轧阶段在整个厚度范围内产生大而粗的铁素体晶粒，而精轧阶段则导致相当细化的小晶粒组织。EBSD的调查证实，在粗轧阶段之后，与表面相比，恢复和变形的晶粒占四分之一和中等厚度。对精轧钢的研究表明，与板的四分之一和中厚部分相比，表面部分主要由变形晶粒组成。通过X射线测量获得的纹理成分表明，在粗加工和精加工阶段之后，{001} <100>，{110} <112>，{123} <634>，{112} <111>和{001 }发现存在<110>个组件。然而，在轧制钢的不同深度观察到织构的不均匀性，因此与表面相比，织构的体积分数和所需的γ-纤维织构的强度在中厚和四分之一厚度段最高。在两个滚动阶段之后。室温拉伸应力-应变曲线表明，从近表面部分获得的样品观察到最高的屈服强度，而从中厚部分获得的样品在拉伸变形过程中显示出最高的伸长率。总体，