B. Tawfik M, A. Mohammed K. The Effect of Niobium and Vanadium on the Toughness of High Strength Alloyed Line Pipe Steel Used in Gas & Oil Pipeline. J. eng. sustain. dev. 2010;14(2):1-16. Accessed May 5, 2025. https://jeasd.uomustansiriyah.edu.iq/index.php/jeasd/article/view/1453