AIP Conference Proceedings [AIP Publishing MECHANICS, RESOURCE AND DIAGNOSTICS OF MATERIALS AND STRUCTURES (MRDMS-2019): Proceedings of the 13th International Conference on Mechanics, Resource and Diagnostics of Materials and Structures - Ekaterinburg, Russia (9–13 December 2019)] MECHANICS, RESOURCE AND DIAGNOSTICS OF MATERIALS AND STRUCTURES (MRDMS-2019): Proceedings of the 13th International Conference on Mechanics, Resource and Diagnostics of Materials and Structures - On the influence of the hardened layer of the inner surface and its roughness on the durability of hollow shafts and axles from hot-rolled tube shells