Processing of high-purity sponge iron pellets to hotand cold-rolled strip

Abstract

This paper follows an earlier publication which described the development of strong organically bonded iron ore superconcentrate pellets and their direct reduction to high-purity sponge iron. In the present paper, the processing by hot rolling under a protective atmosphere of these high-purity sponge iron pellets into steel strip which may be further processed by hot and cold rolling in the usual way is described. The main features of the rotary kiln and its associated vertical large-diameter rolling mill are described in some detail and the important hotrolling parameters necessary for successful processing to fully dense material are outlined. The mechanical properties of the ‘direct steel’ strip product were investigated at each stage of processing, i.e. after initial hot rolling and after subsequent hot and cold rolling; continuous improvement of overall properties, particularly ductility, is noted.