HIGH-QUALITY AND HIGH-PRODUCTIVITY CONTINUOUS CASTING TECHNOLOGY AT MIZUSHIMA NO. 4 CONTINUOUS CASTER OF KAWASAKI STEEL

摘要

No. 4 continuous caster at Mizushima works was successfully put into a commercial operation in 1993 for the purpose of high quality slab production for steel strips and lead time reduction by synchronized operation between the caster and the hot strip mill. Since then, in response to customer's requirements that was becoming stricter year after year, KSC put its weight to improvement in slab quality and productivity so that the No.4 caster could realize timely supply of higher quality slabs to the following process. In terms of productivity, KSC focused on increase of casting rate and reduction of non-operation time. While, it is generally hard to increase casting rate suppressing surface defects due to mold flux entrapment and internal cracks. Considering this problem, the following measures were tested and have commercially been applied at the No. 4 caster to achieve very high casting rate. (1) Reduction of mold flux entrapment thanks to appropriate molten steel flow at meniscus with "Flow Control Mold" (FC Mold) (2) Achievement of very high casting rate with no significant internal crack by optimizing secondary water cooling patterns, roll gap and mold flux. In regard to lowering non-operation time, a kind of "Market Oriented Agile Production Control System", MAP system, has been introduced to realize longer sequential casting maintaining good synchronization with the following process. Thanks to the measures mentioned above, the productivity of the No. 4 caster was significantly improved and has now reached approximately 3.5 million tons per year.