Research on the variation of the inclusion and sulfur content in Pipeline steel Tongsheng Zhang, Rensheng Li, Wanlin Wang, Shifan Dai, Peisheng Lv and Yan Tian Metall. Res. Technol., 118 2 (2021) 214 Published online: 25 March 2021 DOI: 10.1051/metal/2021010