This study presents the development and qualification of sour‑grade API X60 steel for 16”–24” LSAW pipes for the Dos Bocas Refinery project. Production employed KR desulfurization, vacuum degassing, and strict casting controls to minimize inclusions and segregation. Two chemistries were evaluated: DOE‑1 (w/o Ni/Cu) and DOE‑2 (with Ni/Cu). Microstructural analysis showed that DOE‑1 produced a finer, more homogeneous polygonal ferrite matrix due to the absence of Ni/Cu‑induced solute drag, whereas DOE‑2 exhibited coarser grains and higher segregation sensitivity. Compared with conventional non‑sour API X60, sour grade designs demonstrated improved microstructural uniformity and enhanced resistance to hydrogen‑assisted damage. Mechanical testing confirmed that DOE‑1 achieved superior ductility, lower anisotropy, and improved low‑temperature toughness relative to DOE‑2 and conventional X60, while DOE‑2 showed higher strength but greater variability. Both the DOEs met NACE TM0284 and TM0177 HIC/SSCC criteria, with DOE‑1 displaying slightly higher crack‑resistance consistency.