Development of Continuous Casting Technology in the Steel Industry of Japan (I) -From Experimental Application to Commercial Implementation in Low Grade Steels-

Abstract

Research and experiments of continuous casting (CC) of steel in Japan were started in 1947. The first semicommercial facil ies were built in late 1950's with the intention of applying CC to quality special steels to which the CC technology had been supposed to be bestfit in consideration of yield ratio and energy economy. The CC for special steels, however, came to a standstill because the quality requirements to the final products were not fulfilled. Successful implementation of the CC took place firstly in the late 1960's, in production of low quality billets mainly for cement concrete reinforcing bars, where the CC worked as a labor-saving process. In parallel with the billet CC, large-section slabs for rather low grade steel plates began to be continuous-cast, where the CC worked as an energy-saving and capital-saving (enabling omission of blooming mill) process. The slab CC achieved a high productivity compatible to that of basic 'oxygen furnaces but still failed to meet the steel quality required for sheet production. Essential contribution to the development of the CC technology came from practical know hows and improved equipments brought about by above-mentioned industrial operation for low grade steels rather than by the so-called R&D in laboratories. A further development of the CC technology especially in regard with steel quality and comparative-historical consideration thereabout will be given in a subsequent paper