A parameters design approach to improve product quality and equipment performance in hot rolling

This study presents the application of parameters design to improve both the product quality and the equipment performance in a hot sheet rolling plant. Three empirical models were developed to predict and explain the relationship between variation in some process parameters and the type and range of product defects together with equipment disorders observed. The investigation is based on the analysis of the results of a set of designed experiments. The most critical process parameters were set at specified values and the effect of the change in these parameters, on rolled sheets quality and rolling equipment performance is evaluated. The three process parameters considered are the reduction ratio (Rd), the slab temperature (Ts), and the exit strip speed (Sp). The quality characteristics considered are: profile and flatness of rolled sheets and distance between chatter marks, the performance indicators considered are: rolling force, vibration measurements, and the rolling mill wear rate. Through optimization of process parameters, it was possible to reduce chattering. Consequently, chatter marks and roll wear were greatly reduced. Product flatness and profile were improved. Plant down time and production scrap was considerably reduced. This investigation proved that it is possible to improve both product quality and equipment performance in the hot rolling plant through the parameters design approach.