日本の鉄鋼業における連続鋳造技術の発展（Ⅱ） -品質課題の克服と成熟への道-

抄録

This paper deals w h the later stages of the continuous casting (CC) technology in the steel industry of Japan, while our previous paper described the history of CC from s introduction to the early stages of commercial implementations. From late 196〇,s, the CC technology had been reinforced by several auxiliary and peripheral techniques. Firstly, nonmetallic inclusions and surface defects were reduced by introduction of large sized tundishes, immersion nozzles, vacuum degassing with argon bubbling, and powder casting. Such reinforcing techniques (RITs) en masse enabled CC (killed) steel slabs to replace rimmed steel ingots for thin sheets, the main product of the integrated steel mills. Another notable RIT, electromagnetic stirring, became available in late 19?〇,s, which remarkably improved metallurgical structure and minimized segregation of elements in CC blooms. This method in concert with the above-mentioned RITs was successfully applied tQ casting of special steel blooms for mechanical use products. Thus the CC technology grew to meet most kinds of steels and, by 1985, to replace ingot casting process almost entirely. Through the history of Co, it is noted that those various RITs were developed in the course of mass production of low grade products. Such situation can be compared to the history of the semiconductor industry where basic advancement of transistor and IC technologies took place in production of popular goods such as portable radios, quartz-oscillator watches and/or pocket calculators.