For the purpose of investigating the inside of operating blast furnace, Higashida No. 5 B.F. (inner volume 646 m3) was dissected and examined, after quenched with water under normal operating condition in 1968. This was the first trial in Japan of dissecting a commercial blast furnace.
Next, Hirohata No. 1 B. F. (inner volume 1407m3), which had been operated with considerably high productivity, was dissected in 1970.
Thirdly, Kukioka No. 4 B.F. (inner volume 1279m3) was also dissected in 1971, so as to clarify the features of low coke ratio furnace.
In this paper, the procedure of dissection, the general views on the inside of these furnaces, the characteristics of each furnace, and the relationships between the inside state and operating conditions are described.
