Effect of asymmetric material entrance on lubrication in cold rolling
L. Jacobs, K.N.H. van Dam, D.J. Wentink, Matthijn de Rooij, Jeroen van der Lugt, Dirk J. Schipper, J.P.M. Hoefnagels
Abstract
An Integrated Digital Image Correlation (IDIC) method has been applied to the cold rolling process, the images clearly visualise the geometry of the roll bite and the inlet zone. A key, novel finding is that despite using coils and applying entry tension, the strip can enter asymmetrically in the rolling mill. Moreover, it is shown that asymmetric strip feeding results in an uneven lubricant film thickness between top and bottom strip surface. A method is detailed to feed the strip truly symmetrically in the mill, a procedure that is necessary for a meaningful experimental validation of lubricant film thickness models. For symmetric rolling processes the measured film thickness corresponds significantly better with the theory than for asymmetric processes.