GB1325883A - Method of and apparatus for revising workpiece temperature estimates or measurements using workpiece deformation behavior - Google Patents

Abstract

1325883 Rolling mills GENERAL ELECTRIC CO 8 Sept 1970 [7 Oct 1969] 42989/70 Heading B3M A method of revising a measured or estimated value of workpice temperature in a rolling mill comprises using a function of temperature-roll force characteristics for the mill to predict the expected roll force from the temperature value, measuring the actual roll force and using the discrepancy in roll force values to deduce the temperature error. This revised temperature is used to modify the established temperature value and also to control a screwdown control. The workpiece is fed from a furnace 10 to a roughing mill 16 for several passes and to a finishing mill 22. The functions are initially established experimentally for different working conditions. The measured or estimated temperature Ti is used to extract an expected roll force Fi. The actual roll force Fa is measured by a load cell 32 and used to deduce the actual temperature Ta. The revised temperature Tr is the average of Ti and Ta and is fed to a screwdown control system 38. The revised temperature is also used as the established temperature for the next pass. The workpiece temperature may not be critical in the early roughing passes and the automatic control may be used only on the last roughing pass. Alternatively the average difference between Ti and Ta may be used to determine the new established temperature for the next pass. A further method uses the function of roll force ratio Fa/Fi against temperature to deduce the actual temperature, This function is linear over a small range so that the temperature error can be calculated using the function gradient and the roll force error. The values of Fa/Fi for successive passes are stored and averaged and compared with a force value ratio of 1À0 to establish the roll force error. The signals between the control parts may be analog or digital.