Copyright 2003, The AISE Steel Foundation, Pittsburgh, PA. All rights reserved.123.1 IntroductionNear-net-shape casting of flat products is one of the true technological adventures that the steel industry has undertaken in the last 20 years.129The subject is still young, as only about 10 years have elapsed since the emergence of the first commercial near-net-shape casting technologythat being thin-slab casting. The literature on this subject is certainly abundant and oriented toward action, especially commercial action, but is more descriptive than analytical or critical. A review of this subject may therefore be both useful and necessary, but is limited in scope to a subjective presentation by this author due to the nature of the material available in the open literature.In spite of these difficulties, this chapter will endeavor to: review the history of the field, point out the strong development of the thin-slab casting concept, with due recog- nition of its present trends, which are moving it away from the initial mini-mill phi- losophy, and offer some ideas about the potential of strip casting in advancing farther away from the classical integrated mill concept.23.2 A Short History of Near-Net-Shape CastingFig. 23.1 presents the recent history of near-net-shape casting for flat products.At the root of near-net-shape casting lies rapid solidification technology (RST), a young scientific discipline that emerged in the early 1970s. The filiation from RST to near-net-shape casting was never direct, as very few large-scale applications were developed in the megaton range of annual production, which is the plant scale of interest to the steel industry. The amorphous material that it produces might have displaced silicon steels for motor and transformer core applications, but this never materialized in spite of the efforts of Allied-Signal in the 1970s and 1980s.RSTs role in the steel industry in the early 1980s was mainly to show that near-net-shape casting might be a possible through its extension of conventional continuous casting.3,3032The near-net-shape casting concept was first appropriated by integrated steel companies and by tech- nology providers such as the Hazelett Corp. in the U.S. to develop a tool for replacing conventionalChapter 23The Future of ContinuousCastingJean-Pierre Birat, Manager, IRSIDCasting Volume2Copyright 2003, The AISE Steel Foundation, Pittsburgh, PA. All rights reserved.continuous casting and the roughing stands of the hot strip mill (HSM) on a quantitative production basis, i.e., equipment for equipment. The idea was to change only the technology employed and con- tinue with business as usual in other areas of mill management. Casting between belts, a technology that had been quite successful in the nonferrous business, looked like it had the potential to fulfill this rather demanding agenda.After much money and time was spent on the concept in the U.S. (Hazelett, Nucor, U. S. Steel, Bethlehem Steel), in Japan (Kawasaki Steel, Nippon Steel) and in Europe (Ugine, Krupp Stahl), it became clear that the technology could not be brought up to the expected level, and it was all but abandoned.3At the same time that the twin belt technology was being pushed forward, the concept of strip cast- ing was being picked up as a working subject by a large number of research organizations all over the world. It was both a declaration of faith in the potential of innovation by the steel industry and a somewhat naive underestimation of the technological problems to be overcome. The agenda in this case was to do away almost completely with hot rolling and to replace the hot side of the steel mill with steelmaking and casting facilities. The concept today, after 20 years of research and development, is just emerging as commercially viable.Last in this historical schedule, but certainly not least in practical importance, is the thin-slab cast- ing concept launched by German equipment manufacturers in the 1980s. They were able to reach satisfactory results quickly and to commercialize the process at a time when the U.S. was in need of more steelmaking capacity, and when newcomers to the steel business there were bold enough to employ this technology to start their new businesses. Thin-slab casting today has turned out to be tremendously successful.The fascination with and success of near-net-shape casting technologies are certainly not limited to process and engineering viewpoints, but are closely related to the core business of the steel industry. One important aspect of this business connection is explained on the graph in Fig. 23.2, where the cost of building a greenfield steel mill is plotted on the vertical axis versus the specific cost per ton of annual steel capacity. For newcomers interested in commodity flat rolled steel pro- duction for a local market, the mini-mill is clearly a more attractive solution than an integrated mill.Integrated mills, which we may call the standard mod