Corus R,D&T (formerly British Steel), Teesside Technology Centre together with Scunthorpe Works, ISPAT-Hamburger Stahlwerke, Sidenor IzD and Corus NL (formerly Hoogovens) completed in 2002 an extensive ECSC supported study to evaluate techniques to optimise the central segregation during the continuous casting of high carbon billets. The study included the application of intense secondary cooling, thermal soft reduction, final electromagnetic stirring (EMS), reduced and controlled superheat casting and mechanical soft reduction. In addition, the influence of casting process variables (casting speed, open and submerged pouring etc.) and their interaction with the technologies studied was investigated. From the investigations on the casting machines of the four partners in the project it was possible to recommend an optimum strategy for the minimisation of segregation in the casting of high carbon billets.
An adiabatic calorimeter has been used to measure heat capacities and heats of transformation for iron-eobalt alloys over the temperature range 700-1500K. Estimates of the entropy associated with magnetic and configurational disorder suggestthat f'V 75% of the magnetic order is lost by the Curie temperature and that although the Bragg-Williams theory correctly predicts the entropy of disordering FeCo, it overestimates the entropy of disordering alloys away from the ideal ordering compositions. Phase-diagram information for the oc-+y transformation, the ordering reaction, and the Curie temperature are given.This investigation was initiated at a time when the data available on the heat capacities l -4 and heats of transformation of iron-cobalt alloys5 were limited to early studies over restricted ranges of temperature. More recently, four more studies of heat capacities have become available,6-9 but the majority of the effort has been concentrated on alloys close to the FeCo composition, whereas this study covers the range from xco=0·018 to 0·942. The present results form part of a programme of thermodynamic' measurements on solid alloys of iron with transition elements which is being carried out in the Department of Metallurgy at Sheffield University with the long-term objectives of improving the understanding of alloying behaviour and of developing models to predict thermodynamic quantities in ternary and more complex iron alloy systems as well as obtaining phase-diagram information.There is good agreement between Yokoyama, 3 Masumo'to et al.,5 Castanet anti Ferrier,6 and the present study in defining the order-disorder temperature for the FeCo compositions as 999-1002 K. Mills,9 Ansano et al.,4 and Kaya et al.I favour a higher value of 1006-1009 K whereas Pepperhoff and Ettwig 8 record a lower value of 983 K.Heat-capacity effects associated with the order-disorder transformations have been observed over the composition range xco=0'29 to 0.70 2 ,4,9 and a second maximum in the heat-capacity curves at-f'V 823 K has been reported for alloys in the range xco=0·35 to 0'67.1,2 This second peak is reported to be very sensitive to heat-treatment and to become very much smaller in furnace-cooled specimens than in material which had been rapidly cooled.The present study is connected with previous investigations of pure iron ll and pure cobalt 12 carried out by Sale and by Normanton. ExperimentalThe spherical adiabatic calorimeter and its mode of operation have been fully described in previous publications. 1l -14 Alloys were prepared by vacuum melting electrolytic iron and electrolytic cobalt. As the oxygen content of the iron was comparatively high ( f'V 550 ppm by weight), this was deoxidized y vacuum melting with a small amount of carbon to prepare a suitable melting stock for the preparation of the alloys. These were generally cast as 750 g ingots into 25 mm dia. chill moulds, but in the case of the alloy xco=0'495, a 75 mm ingot was cast from an 8 kg melt. \ The 25 mm ingots were hot rolled to 19 mm dia. from an init...
Corus R,D&T at Teesside Technology Centre has developed over a number of years a mould thermal monitoring (MTM) system based on an array of thermocouples in the mould copper plates. The system is installed on the Corus slab casters in the UK, on slab casters at Outokumpu (UK), Sidmar (Belgium) and Kosice (Slovakia) and, at the time of the 4th European Continuous Casting Conference, was also on the medium thickness slab caster at Tuscaloosa (USA), which was sold to Nucor in 2004. The MTM system was also under development on the thin slab caster at Trico (USA) before plant closure (subsequently bought by Nucor), and aspects are currently being developed on the Corus DSP (direct sheet plant) thin slab caster at IJmuiden (The Netherlands). While a prime function is detection and prevention of sticker type breakouts, the MTM system allows real time assessment of thermal conditions, provides a valuable input for online grading and, most important, enables modifications to mould powder practices to be assessed. The present paper briefly outlines recent developments to the MTM system and presents examples of the use of the system to assist mould powder developments.
Based on a presentation at the 6th International Conference on 'Molten slags, fluxes, and Slab casting salts' held in Stockholm and Helsinki on 12-16 June 2000.In all cases, the data obtained from the questionnaire consisted of the usual or well known properties, i.e. viscosity,
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