All-Russian Scientific and Research Institute of Tube Industry — RosNITI (Chelyabinsk, Russia):

A. V. Vydrin, Dr. Eng., Prof., Deputy General Director on Scientific Work, e-mail: vydrinav@rosniti.ru
E. V. Khramkov, Cand. Eng., Head of the labor for simulation of technological processes
M. A. Pavlova, Senior engineer, the labor for simulation of technological processes

Volzhsky Pipe Plant (Volzhsky, Russia):

A. S. Zhukov, Director on Product Quality

The type of metal stress-deformed state during pipe extrusion influences technological process parameters and hot extruded pipe quality. Existing experimental research methods do not determine stress and deformation areas in a deformation zone. So, the existing information about pipe extrusion is theoretic and speculative. During last years computer simulation methods was developed, in particular software based on the finite element method. This leads to the possibility to make analytical researches of stress-deformed state during steel pipe hot extrusion. Special attention during simulation is focused on deformation conditions in surface layers because common defect of hot extruded pipe surface is surface cracks and delamination. For potential surface cracks forecast it is necessary to estimate stress state, flow rate and temperature of metal. Therefore, information obtained by the computer simulation favours forecasting of pipe surface quality, metal quality and searching ways to reduce cracking. With this aim, numerical data, describing changes along the deformation zone, a deformation tenzor component, the level of accumulated deformation stress-strain concerning temperature and friction ratio, was approximated. Moreover, the computer simulation of stress-deformed state during extrusion allows estimating the adequacy of simulating metal flow during pipe extrusion.

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