Analysis of flatness control capability based on the effect function and roll contour optimization for 6-h CVC cold rolling mill
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The 6-high continuously variable crown (6-h CVC) cold rolling mill shows limited capability to control coupled edge and center waves for both narrow strip and ultra-wide strip production. In order to solve this problem, an integrated three-dimensional (3D) elastic-plastic finite element model (FEM) of rolls and strip is built to calculate the effect functions in consideration of work roll bending (WRB), intermediate roll bending (IMRB), and CVC intermediate roll shifting (IMRS) with different strip widths. A set of orthogonal vectors which is defined as eigenvectors is proposed to analyze the similarities and the complementarities of the effect functions. It is applied to study the flatness control characteristics of the cold rolling mill. Based on the analysis of flatness stress characteristics of different strip widths in the production, it is found that the similarities between the flatness stress and the eigenvectors of different strip widths are relative low. The flatness defects are difficult to be eliminated. From the relationship between IMRS and strip widths, a segmented CVC intermediate roll contour is then proposed and experimented in an industrial production. The proportion of coupled edge and center waves is decreased by 15.2%, and the overall flatness is reduced by 0.7 IU.
Keywords6-h CVC cold rolling mill Effect function 3D FEM Flatness control Roll contour
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This work is supported by “the National Key Technology R&D Program of the 12th Five-year Plan of China” (grant no. 2015BAF30B01) and “the Fundamental Research Funds For the central Universities” (grant no. FRF-BR-16-025A, FRF-TP-15-016A3). The authors also thank Wuhan Iron & Steel (Group) Corp. for the industrial experiments and financial support.
- 4.Huang HG, Shi YQ, Ren XY, Du FS (2014) Influence of initial crown of work roll on strip shape adjusting performance of ultra-wide 6-h CVC mill. Iron and Steel 49:88–93. https://doi.org/10.13228/j.boyuan.issn0449-749x.2014.07.004 Google Scholar
- 5.Linghu KZ, Jiang ZY, Li F, Zhao JW, Yu M, Wang YQ (2014) FEM analysis of profile control capability during rolling in a 6-high CVC cold rolling mill. Adv Mater Res 988:257–262. https://doi.org/10.4028/www.scientific.net/AMR.988.257 CrossRefGoogle Scholar
- 8.Yang GH, Zhang J, Cao JG, Li HB, Huang QB (2016) Effect of different stands of 2180mm tandem cold rolling mill on shape control of products. J Beijing Inst Technol 36:1111–1116. https://doi.org/10.15918/j.tbit1001-0645.2016.11.003 Google Scholar
- 9.Bao RR, Zhang J, Li HB, Jia SH, Liu HJ, Li XJ (2015) Influence of asymmetric flatness errors on strip wandering in continuous annealing lines. Iron and Steel 50:35–38. https://doi.org/10.13228/j.boyuan.issn0449-749x.20140726 Google Scholar
- 10.Zhang QD, Huang LW, Zhou XM (2000) Comparative study on shape control technologies for wide strip mill. J Univ Sci Technol Beijing 22:177–181. https://doi.org/10.13374/j.issn100-053x.2000.02.023 Google Scholar
- 11.Wang RZ, He AR, Yang Q, Zhao L, Dong HR (2006) Profile control capability of LVC work roll contour. Iron Steel 41:41–44. https://doi.org/10.13228/j.boyuan.issn0449-749x.2006.05.010 Google Scholar
- 14.Bald W, Klamma K (1988) CVC technology for cold rolling mills-plant examples. Iron Steel Eng 65:24–28Google Scholar
- 15.Wang CS, Zhang YP, Zhang QD (1999) Application of evaluation function in cold mill shape control. Steel Rolling 4:28–30. https://doi.org/10.13228/j.boyuan.issn1003-9996.1999.04.011 Google Scholar
- 16.Zhang YP, Wang CS (1999) Flatness control strategy on cold mill based on efficiency function. J Univ Sci Technol Beijing 21:195–197. https://doi.org/10.13374/j.issn100-053x.1999.02.056 Google Scholar
- 18.Song L, Shen MG, Yang LP, Liu J, Wang JS, Chen XB (2016) Shape control dimensionality reduction efficiency inherited regulation method of cold rolling wide strip. Iron Steel 51:70–75. https://doi.org/10.13228/j.boyuan.issn0449-749x.20150083 Google Scholar
- 30.Bao RR, Zhang J, Li HB, Jia SH, Liu HJ, Xiao S (2015) Flatness pattern recognition of ultra-wide tandem cold rolling mill. Chin J Eng 37:6–11. https://doi.org/10.13374/j.issn2095-9389.2015.s1.002 Google Scholar
- 32.Chen XR (1998) Historical backgrounds and present state of the least squares method. J Univ Chin Acad Sci 15:4–11Google Scholar
- 33.Li HB, Bao RR, Zhang J, Jia SH, Chu YG, Liu HJ (2016) Cluster analysis of strip flatness characteristics for ultra-wide cold rolling mill. Chin J Eng 38:1569–1575. https://doi.org/10.13374/j.issn2095-9389.2016.11.009 Google Scholar
- 34.Ester M, Kriegel HP, Sander J, Xu XW (1996) A density-based algorithm for discovering clusters in large spatial databases with noise. In: The Second International Conference on Knowledge Discovery and Data Mining (KDD-96), Portland, USAGoogle Scholar
- 35.Li HB, Zhang J, Cao JG, Wang ZM, Wang Q, Zhang SS (2010) Analysis and selection of crown control ranges for CVC work rolls in CSP hot rolling. J Univ Sci Technol Beijing 32:118–122. https://doi.org/10.13374/j.issn1001-053x.2010.01.002 Google Scholar
- 36.Liu GM, Di HS, Guang A (2008) Discussion on design of CVC roll profile and its equivalent crown. J North Univ 29:1443–1446Google Scholar
- 37.Wei GC, Cao JG, Zhang J, Hai JW, Chen G (2007) Optimization and application of CVC work roll contour on 2250 hot strip mills. J Cent South Univ 38:937–942Google Scholar