• MATSUSHITA Toshirou, NAKAYAMA Katsumi, FUKASE Hisahiko, OSADA Shirou

IHI started development of the strip caster in 1982, and successfully achieved continuous casting by a laboratory caster, which was then expanded to collaboration with BHP (currently BSL) of Australia in 1989. The pilot plant for 5-ton melt was constructed and succeeded in casting. Next, a commercial scale demonstration plant for 60-ton melt was built in 1994, which progressed well. For further development, Nucor of the USA joined with IHI and BSL in 2000 and established a joint corporation, Castrip LLC. The first commercial facility was constructed at the Crawfordsville Steel Works of Nucor and has produced 650 000 tons of low carbon steel strips as of 2007 since the start-up in 2002. Ultra thin Cast steel Strips (UCS, 0.85 to 1.5 mm thick) produced by the caster are now selling well in the market of those from the conventional hot/cold strip rolling mills. IHI has received an order for a second commercial facility to be operated in early 2009. Furthermore, the strip caster has the potential to achieve the dream of competitiveness in producing value-added products that cannot be achieved by the conventional slab casting & rolling processes.

• TAZOE Nobuhiro, DODO Yasushi, NISHII Takashi

The first slab-width sizing press at the Kashima Works of Sumitomo Metal Industries was installed in 1985. 13 similar presses have been installed and operated at steel producers during the last 20 years. Before the emergence of the sizing press, Hot Strip Mill (HSM) lines consisted of multiple vertical and horizontal rolling mill stands. This vertical and horizontal combination had many technical problems. Many model tests and numerical analysis were required, as were newly designed equipment based on the results obtained from the tests and analyses. This paper describes the progress in the use of HSMs and the advantages of the sizing press together with equipment features and slab deformation characteristics after the press process.

• HONJO Hisashi, SATO Masayoshi, KUCHI Masahiro

Various types of shape control actuators for strip and plate rolling use are used worldwide (“shape” here means both strip flatness and strip crown). IHI has also supplied some types of shape control actuators for hot and cold rolling mills in ferrous and nonferrous fields according to customer’s requirements and conditions. These IHI shape control actuators are described and the characteristics explained along with fields in which they are applied and their performance. Today, IHI mainly supplies roll shifting actuators for shape control in hot steel rolling, for use with specially selected roll ground curves.

• SATO Masayoshi, KUCHI Masahiro

IHI has developed the Profile and Flatness Set Up System (PFSU) in order to improve crown and flatness control in hot rolling mills. This system provides high controllability and accuracy when used with the CNP® (Combined Numerical Profile) Mill developed by IHI in hot rolling operations, and shape quality is also improved significantly. These improvements have satisfied customer requirements. The latest IHI technique for shape control in hot strip mill and reversing finishing mill is described below.

• HONJO Hisashi, YUSA Satoru, MIKAMI Masao, YAMAGUCHI Masahito, ISHII Hajime

Thin steel strip rolling performance in the hot strip mill train has been investigated, mainly the metallurgical microstructure. A compact hot mill train producing ordinary steel strip with 1.2 mm final thickness was assumed, and the characteristics were theoretically calculated and analyzed. Strip temperature drop is large due to the thin thickness causing higher flow stress and higher rolling load. Finishing mill delivery temperature (FDT) falls under the Ar3 transformation temperature. Nevertheless, the calculated results have shown similar microstructure as that of cases with FDT above the Ar3 temperature, suggesting normal metallurgical quality of the thin strip. Besides temperature control, various mechanical devices must be taken into consideration to achieve thin strip rolling. Major mill components for the purpose are explained.

• MINOURA Kouji, FUKAMIZU Takashi, KANKO Yuuji

25 sets of new high response control systems developed for the hydraulic roll gap control systems of rolling mills in the end of 2000 were delivered up to the end of 2007. These have features of easy programming, expansibility, and multipurpose use compared with the conventional response control systems developed in 1993. Subsequently, the servo valve diagnosis system was commercialized using its high-speed data processing capacity. The versatile adaptability of the new high response control system permits applying to other controlling units besides the roll gap control. Its technical description and applications are described.

• SATO Kazuyuki

IHI has constructed many aluminum rolling mills in the world besides Japan. Recent IHI rolling mills have incorporated a setting calculation system that has been supplied in corporation with electronic system supplier. This system has an automatic mill setting function with mathematical models obtained from rolling theories as well as actual setting values stored in the database. This has enabled the stable operation of rolling mill line, ensuring rolling accuracy of aluminum strip. IHI and IHI Metaltech will continue to develop and improve rolling technologies.

• TSUZUKI Shigeru, KIRA Yoichi, MISUMI Kenji

The automatic flatness control system, IHI Sheetflat, has been applied to many cold rolling mills since 1985. The pneumatic type shape roll is used as the shape sensor. Recently, requirements for quality products have become much more important. Therefore, performance of the shape roll has also been improved to meet the requirements. Strip shape is evaluated based on the Fourier’s analysis method, and the shape error is corrected by mill actuators. Shape data are sampled for the whole strip length and stored in a computer, which are available as quality management data. Effectiveness of control performance is verified in rolling very thin foils. The number of reference plants using IHI Sheetflat has been increasing continuously.

• TAZOE Nobuhiro, KAKOI Kunihiko, ISHII Hajime, MATSUZAWA Tsukasa, ISHIZUKA Hitoshi

A rolling simulator for the Cluster Mill, especially the 6Hi X and 10Hi X type mills besides the conventional 4-high mill, has been developed for evaluation of rolling thin strips and foils. The evaluation includes roll deflection, pressure of rolls in contact, roll exit thickness distribution, and so on. Characteristics of kiss rolling ( edge parts of work rolls are in contact, except material width ) was clarified with this simulator, and the effect of roll actuators on mill delivery thickness distribution was estimated. The outline of the simulator is described.

• DODO Yasushi

Many advanced technologies have been developed and used in the engineering of rolling mills and rolling mill facilities. To produce steel products, mill lines must be controlled by hydraulic systems that operate with micron accuracy and at high speed and under a rolling force of several thousand tons. The rolling mill engineering technologies applied to unique machines are described herein, including a G2000 shock-test machine used for underwater explosion impact testing and a high-speed feeding system using parallel link motion system for transfer press lines for car bodies.