Modernization of the Equipment of the Continuous Strip Caster of a Hot-Rolling Mill

Abstract

To reduce metal consumption and improve the quality of the finished rolled product, ISPAT-Karmet has begun to modernize the equipment of its 1700 hot-strip mill. The modernization will include the following: automation of control of the thermal and temperature regimes for heating slabs in the continuous furnaces used with the mill; installation of newly designed manifolds in the hydraulic scale-removal system, with Lechler nozzles, to increase pressure in the hydraulic system from 120 to 160 atm; installation of heat-absorbing shields, designed by the Novokramatorsk Machine Plant (NKMZ), on the intermediate roller table between the roughing and finishing trains of the mill; use of rolls made of high-chromium cast iron in the finishing stands; modernization of the automatic process control system, with replacement of the existing equipment by Siemens programmable controllers and the installation of new Klek width gages after the final finishing stand; installation of a new NKMZ-made combination system for laminar cooling of the strip on the runout table of the mill; installation of a closed hydraulic system to control the configuration of the strip (the system was designed by the company Mess) on finishing stands 6–12; installation of a system to automatically regulate the speed regime during coiling. The results obtained from the initial modernization of the equipment on the 1700 hot-strip mill have already eliminated rolled-in scale on the strip surface, reduced metal consumption by 8.7 kg/ton through a reduction in the width tolerance for the strip, increased the service life of the work rolls in the finishing stands from 175,000 to 350,000 tons, expanded the product mix, reduced electric power consumption by 7.0 kWh, and reduced the consumption of comparison fuel by 0.8 kg/ton.