Analysis of Asymmetric Rolling Efficiency for Improving Rolled Strip Accuracy

Abstract

Technology is analyzed for asymmetric rolling in order to improve rolled strip precision in large units: a 1700 strip cold rolling mill and a Severstal Cherepovets Metallurgical Combine 2000 broad-strip mill; in an ArcelorMittal Temirtau (Kazakhstan) 1700 continuous broad-strip mill. Research demonstrates the efficiency of asymmetric rolling for improving rolled strip precision. In the ArcelorMittal Temirtau 1700 broad-strip mill with asymmetric rolling of strip 2.0–3.0 mm thick non-flatness is reduced on average by 31% compared with symmetrical rolling. Trials of asymmetric strip rolling of corrosion resistant steel 12Kh18N10T in a Chelyabinsk Metallurgical Combine 500/1500×1700 reversing four-roll mill demonstrate the possibility of cold strip rolling with standard flatness with mill adjustment for peripheral speed mismatch of the upper and lower working rolls per pass by 2–7% and simultaneous excess of forward tension over the back tension by 3–7%.