Analysis of force fluctuation in order to determine structural defects in hot strip rolling mills

Yıl 2012, Cilt: 1 Sayı: 2, 173 - 186, 27.03.2016

Yaser Jahangardy Mohammad Reza Forouzan Majid. Rostamipour -

Öz

Structural defects of the mill have considerable effect on the product quality in conventional strip rolling. Since the working rolls are in direct contact with the product, geometrical deviation of them is the most effective parameter on the product quality. In this paper a dynamic model for evaluating mill response to different major structural defects for hot strip rolling is presented for the first time. The model has two main sub-models; the stand elastic model and the strip rolling plastic model. Roll surface flattening and the material hardening due to strain and strain rate are the main sources of the nonlinearities in the mill and the rolling process sub-models respectively. In the presented procedure, in each step, both the models were linearized around the steady state working point and the stiffness matrix was updated in each step. The SIMULINK tool of the MATLAB software was employed to simulate the interactions of the sub-models. The model is able to undertake seven stands in a tandem four-high mill simultaneously Defects such as ovality and eccentricity of work roll and backup roll have been modeled and the simulation results are in very good agreement with data gathered from an industrial mill data logger.

Anahtar Kelimeler

Hot strip rolling, forced vibration, structural defect

Kaynakça

• Hu PR. Stability and chatter in rolling, PhD Thesis, Northwestern University, Evanston, 1998.
• Orowan E. The calculation of roll pressure in hot and cold flat rolling. Proc Inst Mech Engrs, 1943; 150(4): 140 – 167.
• Bland DR and Ford H. Cold rolling with strip tension – Part III: an approximate treatment of the elastic compression of the strip in cold rolling. Iron and Steel Institute, 1952; 171: 245 – 249.
• Bland DR and Sims RB. A note on the theory of rolling with tensions. Proc Inst Mech Engrs, 1953; 167: 371 – 372.
• Sims RB. Calculation of roll force and torque in cold rolling by graphical and experimental methods. Iron and Steel Institute, 1954 September; 178: 19 – 34.
• Sims RB. Calculation of roll force and torque in cold rolling by graphical and experimental methods. Iron and Steel Institute, 1954 September; 191 – 200.
• Alexander JM. On the theory of rolling. Proc R Soc London, 1972: 535 – 555.
• Christensen P, Everfelt H and Bay N. Pressure distribution in plate rolling. Annals of CIRP, 1986; 35:141 – 146.
• Gunasekera JS and Alexander JM. Analysis of rolling. Annals of CIRP, 1987; 36:203 – 206.
• Lalli LA. An analytical rolling model including through thickness shear stress distributions. ASME J Engineering Materials & Tech, 1984; 106:1 – 8.
• Venter R and Abd-Rabbo A. Modeling of the rolling process-I. Int J Mech Sci, 1980; 22: 83 – 92.
• Freshwater IJ. Simplified theories of flat rolling-I: The calculation of roll pressure, roll force and roll torque. Int J Mech Sci, 1996; 38(6): 633 – 648.
• Tlusty J, Critchley S and Paton D. Chatter in cold rolling. Annals of CIRP, 1982; 31: 195 – 199.
• Hu PR and Ehmann KF. A dynamic model of the rolling process Part I: Homogeneous model. Int J Machine Tools & Manufacture, 2000; 40: 1 – 19.
• Yan XQ, Sun ZH and Chen W. Vibration control in thin slab hot strip mills. Ironmaking & Steelmaking, 2011; 38(4):309-313.
• Yildiz SK, Forbes JF, Huang B, Zhang Y, Wang F, Vaculik V and Dudzic M. Dynamic modeling and simulation of a hot strip finishing mill. Applied Mathematical Modelling, 2009; 33(7): 3208 – 3225.
• Fan XB, Zang Y and Wang HG. Research on hot rolling mill horizontal vibration. Kang T'ieh/Iron and Steel, 2010; 45(9): 62 – 66.
• Fan XB, Zang Y and Wang HG. Research on hot rolling mill horizontal vibration. Kang T'ieh/Iron and Steel, 2010; 21(15): 1801 – 1804.
• Yarita I and Urukawa K. An analysis of chattering in cold rolling of ultrathin gauge steel strip. Trans Iron and Steel Inst of Japan, 1978; 18: 1 – 10.
• Chefneux L, Fischbach JP and Guozou J. Study and control of chatter in cold rolling. Iron and Steel Engineer, 1984; 17 – 26.
• Sun JL, Peng Y, Liu HM and Jiang GB. Forced transverse vibration of rolls for four-high rolling mill. Journal of Central South University of Technology, 2009; 6: 16.
• Lu YW, Zhang H, Xiong SB and Wang RF. Hot rolling mill vibration analysis based on least squares method. Journal of North University of China, 2009; 30(1): 41 – 45.
• Yan XQ, Cao X and Liu LN. Simulation research on exceptional vibration of mill main drive system. Journal of System Simulation, 2009; 21(11,5): 3439 – 3442, 3459.
• Forouzan MR, Salehi I and Adibi-sedeh AH. A comparative study of slab deformation under heavy width reduction by sizing press and vertical rolling using FE analysis. Journal of Materials Processing Tech, 2009; 209(2): 728 – 736.
• Shida S. Empirical formula of flow stress of carbon steels resistance to deformation of carbon steels at elevated temperature. 2nd report, J.JSTP, 1969; 10: 610 – 617.
• Misaka Y and Yoshimoto T. Formulation of mean resistance of deformation of plain carbon steel at elevated temperature. J of Jpn Soc of Technol of Plast, 1967- 1968; 8: 414 – 442.