Study of internal corrosion on the turning angles in steel pipes Bauyrzhan Manapbayev, Bazartai Alimbayev, Erkegali Amanbayev, Arman Kabdushev and Zhangazy Moldamuratov E3S Web of Conf., 225 (2021) 01004 Published online: 05 January 2021 DOI: 10.1051/e3sconf/202122501004