Energy-saving by Hot Charging and Direct Rolling in the Manufacturing Process of Wide Flange Beams

Abstract

Owing mainly to the development of beam-blank hot charging and direct rolling, the Nippon Steel Corporation has succeeded in saving 50% of the fuel consumed when the oil crisis happened, at the wide flange beam mill in Sakai Works.
These processes have four problems, namely surface-defects of products, rolling temperature, mechanical properties of products and production schedule. The results of the study on these problems are as follows.
(1) Surface-defects were mainly caused by blow holes and influenced by rolling temperature. These have been prevented by optimizing deoxidization, hot scarfing and rolling temperature.
(2) The adequate rolling temperature could be secured by altering the size of the beam-blank based on a simulation for the optimum pass schedule.
(3) On mechanical properties, there is little difference between products (JIS SS41 class) made by direct rolling and by ordinary process.
(4) The application rate of hot charging and direct rolling has been raised exceedingly by the introduction of a production control computer system.