MATHEMATICAL MODELING OF BALLS ROLLING

The paper presents the results of simulation of rolling of balls precise in mass with diameters of 93 and 125 mm in screw calibers in QForm-3D and DEFORM-3D, the stages and initial data of creating a virtual model of ball-rolling mill are described. The stress state of the metal in characteristic points along the rolling axis was analyzed: stress intensity, stress tensor components, average normal stress. The results of mass measurements of balls rolled on new and worn rolls are presented. The quality check of the inner layers of metal was carried out and the hardness of the rolled balls was measured along the vertical and horizontal axes of ball symmetry. Investigation of metal deformation in simulation of ball rolling has shown that heated billet in form of hot-rolled steel rod is well gripped by rolls, rolling process is stable without slipping. Billet metal fills the gauges completely. There are no gaps observed between metal and gauges walls. Breaker cores connecting molded balls are completely separated in the mill rolls. In this case, core is cut by the rolls flange and is pressed into the ball body. Separated ball continues to roll in gauge finishing section, core remains are smoothed, and completely formed ball with a smooth surface appears from the rolls. It was established that in stress-strain state modeling all components of stress tensor have negative value, that is, all components of stress tensor during balls rolling are compressive. Statistical processing of data on weighing rolled balls with a diameter of 93  mm and 125  mm shows that deviation of mass from the nominal does not exceed 1  %. Measurements of hardness along the balls diametric section shows absence of hardness failures in the inner layers of rolled metal, which indicates a good quality of core zone.

1. Tselikov A.I., Barbarich M.V., Vasil’chikov M.V. etc. Spetsial’nye prokatnye stany [Special  rolling  mills].  Moscow:  Metallurgiya,  1971, 336 p. (In Russ.).

2. Granovskii S.P. Novye protsessy i stany dlya prokatki izdelii v vintovykh kalibrakh [New processes and mills for products rolling in  screw calibers]. Moscow: Metallurgiya, 1980, 116 p. (In Russ.). 

3. Kotenok V.I.,  Podobedov  S.I.  Energy-efficient  design  of  rolls  for  ball-rolling mills. Metallurgist. 2001, vol. 45, no. 9-10, pp. 363–367.

4. Peretyat’ko V.N., Klimov A.S., Filippova M.V. Roller grooving in  ball-rolling mills. Part 1. Steel in Translation. 2013, vol. 43, no. 4,  pp. 168–170.

5. Peretyat’ko V.N., Klimov A.S., Filippova M.V. Calibration of rolls  of a ball-rolling mill. Report 2. Izvestiya VUZov. Chernaya metal-lurgiya = Izvestiya. Ferrous Metallurgy. 2013, no. 6, pp. 16–20. (In  Russ.).

6. Romanenko V.P., Sizov D.V. The computer modeling of the helical rolling of large workpieces on a two-high mill. Izvestiya VUZov. Chernaya metallurgiya = Izvestiya. Ferrous Metallurgy.  2010,  no.  11, pp. 13–16. (In Russ.).

7. Chumachenko  E.N., Aksenov  S.A.,  Logashina  I.V.  Mathematical  modeling and energy conservation for rolling in passes. Metallurgist. 2010, no. 8, pp. 498–503.

8. Filippova M.V., Smetanin S.V., Peretyat’ko V.N. Computer simulation  of  large-diameter  balls  rolling.  Chernaya metallurgiya. Byul. in-ta “Chermetinformatsiya”. 2016, no. 9, pp. 75–78. (In Russ.).

9. Gubanova N.V., Karelin F.R., Choporov V.F., Yusupov V.S. Study  of rolling in helical rolls by mathematical simulation with the Deform  3D  software  package.  Russian Metallurgy (Metally).  2011,  no.  3, pp. 188–193.

10. Liu F., Shan D., Lü Y. Experimental study and numerical simulation  of isothermal closed die forging for aluminum alloy rotor. Trans. Nonferrous Metals Soc. China. 2005, vol. 15, no. 2, pp. 136–141.

11. Kapustova M., Kravarik L., Bliznak J. Computer simulation of precision die forging. Machine design. 2011, vol. 3, no. 2, pp.143–146.

12. Gohil  D.,  Maisuria  M.  Computer  Simulation  Technique  for  the  Closed  Die  Forging  Process:  A  Modular  Approach.  Proceedings of the7th WSEAS International Conference on system science and simulation in engineering. 2008, pp. 61–66.

13. Ulik А., Kravarik L., Bernadic L. Research of metal flow in closed  die in precision forging. Slovak university of technology in Bratislava. 2009, no. 27, pp. 113–118.

14. Slagter W., Florie С., Venis А. Advances in three-dimensional forging process modeling. Proceedings of the 15th National Conference on Manufacturing Research. 1999, pp. 73–78.

15. Skripalenko M.M. Computer modeling and experimental studies of  pinning of ingots in a twin-roll mill of screw rolling. Kuznechnoshtampovochnoe proizvodstvo. 2016, no. 12, pp. 22–26. (In Russ.).

16. Ershov A.A.,  Loginov Y.N.,  Demakov  S.L. Assessing  the  consequences of the softening of metal during hot-working by using the  software  package  QForm  V8.  Metallurgist.  2015,  vol.  59,  no.  7,  pp.  659–663. 

17. Maksimov V.M., Khlybov O.S. Simulation of the firmware processes in the screw rolling mill using QForm. Kuznechno-shtampovochnoe proizvodstvo. 2016, no. 12, pp. 17–21. (In Russ.).

18. Kolmogorov V.L. Napryazheniya, deformatsiya, razrushenie [Stresses, deformation, destruction]. Moscow: Metallurgiya, 1970, 229 p.  (In Russ.).

19. Peretyat’ko V.N., Klimov A.S., Filippova M.V. Calibration of rolls  for ball rolling. Vestnik gorno-metallurgicheskoi sektsii Rossiiskoi akademii estestvennykh nauk. Otdelenie metallurgii. 2012, vol. 30,  pp. 44–50. (In Russ.).

20. Peretyat’ko V.N. Ball blank. Zagotovitel’noe proizvodstvo v mashinostroenii. 2012, no. 3, pp. 17–19. (In Russ.).