CONTROLLER FOR COOLING HOT-ROLLED STEEL SHEET

摘要

PURPOSE:To obtain the cooling controller with improved precision in the temp. difference between the upper and lower faces of a hot steel sheet being cooled and in the cooling completion temp. by controlling the amt. of cooling water to be sprayed from the nozzles arranged on the upper and lower faces so that the temp. distribution on the upper and lower faces of the sheet is kept at a predetermined distribution. CONSTITUTION:The relation between the amt. of cooling water to be sprayed from the nozzles 7c arranged on the upper and lower faces and the heat transfer rate of a hot steel sheet 1 is obtained by a first arithmetic means based on the previously given physical properties of the sheet 1. The temp. distribution in the thickness direction is calculated by a temp. distribution arithmetic means from the heat transfer rate at the actual cooling water amt. calculated from the relation between the cooling water amt. obtained by the actual temp. of the sheet 1 at the inlet of the cooler 7 detected by a temp. detecting means and the first arithmetic means and the heat transfer rate of the sheet 1. As a result, the temp. distribution of the sheet 1 being cooled is kept at a predetermined temp. distribution at all times, and the precision in the temp. difference between the upper and lower faces of the sheet being cooled and in the cooling completion temp. is improved.