Basics of the technology of rolling commercial pipes of special purpose from hard to deform steel grades on units with continuous mills with a controlled-movable mandrel

The increase in demand for seamless pipes made of corrosion-resistant austenitic steel grades contributes to the continuous improvement of pipe rolling technologies. The article presents the results of a comprehensive study and development of a technology for rolling commercial long pipes from a continuously cast billet (CCB) of austenitic stainless steel grades on an injection molding machine with a continuous mill with a controlled-movable mandrel. To determine the plastic and strength properties of stainless steel grades in the injection molding line, data from the results of experiments on the Gleeble 3800 complex of SUSU were used. The study used the results of computer simulation in the QForm 3D software package, as well as the results of physical simulation on modern laboratory screw and longitudinal rolling mills. A technology has been developed for the preparation of CWs from stainless steel grades, which makes it possible to completely eliminate all the shortcomings of the cast metal structure. The presence of corrugation on the surface of the working cone of the mandrel completely solved the problem of low resistance of mandrels when piercing stainless steels. Developed and introduced into industrial production at JSC Volzhsky Pipe Plant (JSC VTZ), the technology for rolling CW of steel grades 08-12X18H10T makes it possible to obtain long-length special-purpose pipes of high quality of the inner and outer surface with the required set of operational properties. The relevance of the topic lies in the need to import substitution of special-purpose pipes made of hard-to-deform steel grades, which were previously purchased in the Russian Federation only abroad.