Abstract
The development of pipe rolling has led to the widespread use of continuous mills with a retained mandrel and 3-roll gauges for rolling hollow billets. Consequently, this required the updating of a number of theoretical positions related to changes in kinematics of the process. In the rolling process on a continuous rolling mill, the rolls and the mandrel are operated under difficult temperature conditions and constant cyclic alternating loads; as a result, they are subjected to considerable wear. Therefore, when force values reach critical ones, rolling contributes to emergency situations caused, in particular, by the destruction of the material of working tools (rolls, the mandrel). Moreover, the stated circumstances are mostly found in the first mill stands, where the pipe mate- rial is subjected to great reductions. Due to the fact that the deformation during pipe rolling on a continuous mill is distributed among 5–6 stands, this additionally imposes certain limitations and reduces the possibility of varying the rolling process parameters in a wider range. In this regard, there is a need to develop and adapt mathematical models for calculating, predicting, and selecting an optimal rolling schedule depending on the product mix of a continuous tube rolling mill. As part of this study, a method for determining the energy parameters of the process has been developed on the basis of the energy theory. When preparing the equilibrium equation for the projections of forces on the longitudinal axis, the authors determined average values of pressure at the contact with work rolls and the mandrel. The developed mathematical models and the algorithm for calculating the energy parameters of the process of rolling hollow billets on a continuous mill made it possible to determine with a sufficiently high accuracy rolling force on a continuous tube rolling mill. The dependencies found can be used both for research purposes and the calculation of rolling tables on tube rolling machines with continuous rolling mills.
Keywords
Continuous rolling, tubes, kinematics, rolling force.
1. Vydrin A.V., Struin D.O., Chernykh I.N., Shkuratov E.A., Bunyashin M.V. Teoreticheskie i prakticheskie problemy protsessa raskatki gilz na sovremennom nepreryvnom stane [Theoretical and practical problems of the hollow billet rolling process on a modern continuous rolling mill]. St. Petersburg: Polytechnic University Publishing House, 2015, pp. 72–82. (In Russ.)
2. Shkuratov E.A. Optimizatsiya protsessa nepreryvnoy raskatki gilz s tselyu povysheniya tochnosti goryachekatanykh besshovnykh trub. Diss. kand. tekhn. nauk [Optimization of a hollow billet continuous rolling process to improve the accuracy of hot rolled seamless pipes. PhD diss.]. Chelyabinsk, 2017, 166 p. (In Russ.)
3. Struin D.O. Sovershenstvovanie tekhnologii prodolnoy prokatki trub na osnove sozdaniya i ispolzovaniya novykh nauchno obosnovannykh tekhnicheskikh resheniy. Diss. kand. tekhn. nauk [Improved pipe longitudinal rolling technology by creating and using new science-based technical solutions. PhD diss.]. Chelyabinsk, 2017, 170 p. (In Russ.)
4. J. Wu. Characteristics of the manufacturing process and equipment of ø 508 mm 3 roll pipe mandrel PQF mill. Steel pipe, 2013 (6), vol. 42, no. 3, pp. 44–50.
5. X. Li, Q. Bai, X. Zhou, X. Yin. Optimized design and application of rolls of ø 258 mm mandrel PQF mill. Steel Pipe, 2012, vol. 41, no. 1, pp. 64–68.
6. Sh. Sun, X. Guan, H. Ding, Sh. Ma. Development of technology of PQF process for rolling heavy-wall, extra-sort tube. Steel pipe, 2016, vol. 45, no. 4, pp. 42–45.
7. Potapov I.N., Kolikov A.P., Druyan V.M. Teoriya trubnogo proizvodstva [Theory of tube production]. Moscow: Metallurgy, 1991, 424 p. (In Russ.)
8. Kolikov A.P., Romantsev B.A. Teoriya obrabotki metallov davleniem [Theory of metal forming]. Moscow: MISIS Publishing House, 2015, 451 p. (In Russ.)
9. Pyankov B.G., Vydrin A.V., Shirokov V.V. Developing a computer model of the pipe rolling plant with FQM to measure the impact of disturbing parameters on the rolling process. Sbornik dokladov mezhdunarodnogo nauchno-tekhnicheskogo kongressa OMD 2014. Fundamentalnye problemy. Innovatsionnye materialy i tekhnologii [Proceedings of International Scientific and Technical Congress OMD 2014. Fundamental problems. Innovative materials and technologies]. Part 2. Moscow: LLC White wind, 2014, pp. 95–102. (In Russ.)
10. Druyan V.M. Gulyaev Yu.G., Chukmasov S.A. Teoriya i tekhnologiya trubnogo proizvodstva [Theory and technology of tube production]. Dnipropetrovsk: RIA Dnepr-VAL, 2001, 544 p. (In Russ.)
11. Vydrin A.V., Shirokov V.V. Computer simulation of pipe continuous rolling speed. Stal [Steel], 2011, no. 2, pp. 56–58. (In Russ.)
12. Osadchiy V.Ya., Vavilin A.S., Zimovets V.G., Kolikov A.P. Tekhnologiya i oborudovanie trubnogo proizvodstva [Pipe production technology and equipment]. Moscow: Intermet Engineering, 2007, 560 p. (In Russ.)
13. Vydrin V.N., Fedosienko A.S., Krainov V.I. Protsess nepreryvnoy prokatki [Continuous rolling process]. Moscow: Metallurgy, 1970, 456 p. (In Russ.)
14. Khramkov E.V. Povyshenie effektivnosti izgotovleniya goryachedeformirovannykh trub na osnove fizicheskogo i matematicheskogo modelirovaniya protsessa redutsirovaniya. Diss. kand. tekhn. nauk [Improving the efficiency of manufacturing hot worked tubes based on a physical and mathematical simulation of the reduction process. PhD diss.]. Chelyabinsk, 2017, 165 p. (In Russ.)
15. H. Ku, G. Xiao, Y. Chang, P. Zhang. Development of structure of 3-roll mandrel pipe mills and relevant comparative analysis. Steel Pipe, 2015(6), vol. 44, no.3, pp. 59–62.
16. X. Wang, W. Yang, F. Hu, K. Xia, C. Bai. Optimization of process equipment and production practice of ø460 mm PQF plant. Steel Pipe, 2014, vol. 43, no.3, pp. 49–54.
17. Q. Fan. Advanced technologies and equipment applied to ø159 FQM 3-roll mandrel mill plant. Sichuan Metallurgy, 2015(2), vol. 29, no. 1, pp. 19–22.