PROCESS OPTIMIZATION AT CONTINUOUS REHEAT ING FURNACES WITH THE AID OF MEASUREMENT DATA FROM THE DOWNSTREAM DEFORMATION STAGES

The objective of the studies was to improve the process control realiz ed by thermal furnace models at pusher-type furnaces. In this connecti on a special on-line model was developed and applied in trials. Using rolling force measurements as a basis, it determines the temperature r elevant for the deformation of slabs after they are discharged from th e furnace. Results of the model calculations are presented. The on-lin e model first of all simulates the pre-given process sequence and crea tes a reference standard. Based on the evaluation of the pyrometric en try-bar temperature after the last pass and the rolling force, the bas ic value for the deformation resistance is adaptively determined. The latter value is used to establish the temperature relevant for the def ormation of the entry bar per pass, to form statistically reliable dif ferential values in relation to the reference standards and, on this b asis, to determine the effective discharge temperature. The studies sh ow that the model should be utilized if more exact knowledge of slab r eheating is required for the control of the process. This applies to p recisest possible discharge temperatures, the ascertainment of slab he ad- and tail-end values, and the assessment of skid mark formation.