National University of Science and Technology "MISIS" (MISIS), Russia:

N. M. Vavilkin, Dr. Eng., Chair of Technology and Pipe Production Equipment

A. V. Krasikov, Postgraduate, Chair of Technology and Pipe Production Equipment, krasikovav@tmk-group.com

The paper describes improvement of the classic method of shell rolling with manufacturing of rough tube in 7-9 2-hi stands with long mandrel. Manufacturers of tube products put into practice the technology of continuous tube rolling at controlled and transferred mandrel in 3-roll passes during building the new production facilities and modernizing the existing ones. These 3-roll passes are designated as PQF (Premium Quality Finishing) and FQM (Fine Quality Mill). Shell reduction by three rolls in combination with controlled transfer of mandrel provides more favourable stress-strain state of metal what respectively has positive effect on quality of finished tubes. Nevertheless, increase of tube wear resistance is required, owing to hard temperature and force operation conditions of mandrels. Complex mathematical model of thermal and thermal-stressed state of mandrels in tube rolling has been developed. It allows to calculate mandrel temperature field and volumetric stress distribution at every moment. Complex comparative analysis of kinematic, deformation and thermal operating conditions of mandrel in classic continuous rolling with controlled transfer in 3-roll passes. Additionally, recommendations for welding deposition of the most wearable areas of technological tool are given. The results of investigation has been put into practice at TPA-80 continuous tube rolling mill of Sinarsky Tube Works.

1. Chikalov S. G. Proizvodstvo besshovnykh trub iz nepreryvnolitoy zagotovki (Production of seamless tubes from billets). — Volgograd: Volgograd State Technical University, 1999. — 408 p. 

2. Danchenko V. N., Chus A. V. Prodolnaya prokatka trub (Longitudinal Pipe Rolling). — M.: Metallurgiya, 1976. — 136 p. 

3. Vavilkin N. M., Bukhmirov V. V. Proshivnaya opravka (Piercing mandrel). — M.: National University of Science and Technology "MISIS" (MISIS). 2000. — 128 p. 

4. Vavilkin N. M., Krasikov A. V. Izv. vuzov. Chernaya metallurgiya – News of the Higher Schools. Ferrous Metallurgy. 2009. No. 11. pp. 22–25.

5. Vavilkin N. M., Krasikov A. V. Proizvodstvo prokata – Production of Rolled Stock. 2010. No. 8. pp. 25–28.

6. Krasikov A. V., Vavilkin N. M. Proizvodstvo prokata – Production of Rolled Stok. 2011. No. 4. pp. 26–28.

7. Romantsev B. A., Vavilkin N. M., Lube I. I., Krasikov A. V. Izv. vuzov. Chernaya metallurgiya – News of the Higher Schools. Ferrous Metallurgy. 2011. No. 5. pp. 27–30.