Ironmaking & Steelmaking: Processes,Products and Applications

In 2002 the European Union (EU) established the Research Fund for Coal and Steel (RFCS) to exploit the interest of the capital that was left after termination of the European Coal and Steel Community (ECSC). The first period of existence of the RFCS has been analysed by a team of experts from the coal and steel sector and their findings collected in a Monitoring and Assessment Report. This report describes the way the RFCS is managed by the European Commission in terms of setting up of priorities for annual calls, evaluating the project proposals and ranking them for funding. Also the way the Technical Groups monitor the progress of the projects is analysed. The report contains suggestions for further improvement. In the Assessment part the M&A Report describes 198 projects that have been finished in the first period of RFCS existence. Benefits achieved by the beneficiaries are collected and where possible expressed in financial terms. A method is introduced to calculate the potential benefit of the RFCS projects when the outcome would have been applied not only at the beneficiaries’ company but at all processes, products and industrial installations in the coal and steel sector of the EU. This information is of direct interest to researchers, technology and R&D directors and company Executive Board members as it illustrates the multiplier achieved from investment in collaborative R&D in the coal and steel sector in the EU.

On the basis of Shagang Group’s 5000 mm heavy plate mills, conventional rolling processes with different broadside rolling ratios were simulated by the three-dimensional rigid plastic thermomechanical finite element (FE) model developed in the author’s previous work. By analysing the simulation results, it was found that the final plate plan view patterns after hot rolling processes were bound closely to the broadside rolling ratio and the finishing rolling ratio. Then, predictive models for plate end edge shapes and side edge shapes were formulated by nonlinear regressive analysis of the simulation results and modified by the lengths of the uneven shapes for higher accuracy. The validity of the prediction models was confirmed by comparing the predicted concavity and convexity lengths with those measured from industrial tests. The predicted plate edge shapes were in good agreement with those of the FE simulation. On the basis of the plate plan view pattern prediction models, methods to improve the plate plan view pattern are discussed.

As an integral part of developing a novel flash ironmaking technology at the University of Utah, the activity of iron oxide in the slag was studied under three different gas atmospheres: H₂/H₂O (H₂), CO/CO₂/H₂/H₂O (reformed natural/coal gas), and CO/CO₂. The conditions of the slags investigated were MgO-saturated CaO–FeO–Al₂O₃–SiO₂–MnO (0·2–0·8 wt-%)–P₂O₅ (0·1–0·9 wt-%) in the temperature range 1550–1600°C with wt-% CaO/wt-% SiO₂ of 0·8 to 1·2, and under pO₂ = 2×10⁻¹⁰–2×10⁻⁹ atm. Water increased the activity coefficient of FeO in the slag and accordingly lowered the FeO content. The average FeO content was found to be 10, 11 and 16 wt-% under H₂/H₂O (H₂), CO/CO₂/H₂/H₂O (reformed natural/coal gas), and CO/CO₂, respectively. An empirical correlation for γ_FeO in slags under H₂/H₂O atmospheres was formulated to givelog γ_FeO = −3·0623 X _FeO−3·1421 X _CaO−2·5068 X _MgO+2·1957

In order to improve the inclusion type and composition in tyre cord steel, ladle furnace refining has been simulated by laboratory experiments and thermodynamic calculation. It was found that slag metal reaction time and top slag composition have an important influence on the inclusion compositions in the final steel. To produce the desired low melting point ductile inclusions the optimum conditions were: reaction time 60 min, basicity (CaO/SiO₂) of top slag in the range of 1·0–1·2 and Al₂O₃ content of slag in the range of 3–9 mass-%. These were then confirmed in industrial trials.

This paper presents a simulation and experiment study on an electromagnetic (EM) sensor system for monitoring the phase transformation of steel strip on the runout table (ROT) of the hot strip mill in Tata Steel IJmuiden. The sensor head contains an H shaped magnetic core and is excited simultaneously at multiple frequencies. A simulation study linking the output of the EM system, in the form of a mutual induction spectrum, to the transformation processes within the steel strip is presented. This is performed by linking the results of thermodynamic models of the transformation behaviour of the steel strip (modelled with the TITAN mill model, property of Tata Steel) with the EM response of the sensor system (modelled with Ansys Maxwell 3D). The simulations are able to show the induction spectra that would be measured for a particular mill set-up and steel strip at different positions over the length of the ROT. The paper further describes the construction and deployment of the sensor head on the IJmuiden hot strip mill and presents the first results from this type of system with data taken during normal production on the mill.

A novel decarburisation process in an RH (Ruhstahl hausen Process) degasser (RH aside spray technique) has been proposed, plant trials have been carried out and the ruling factors have been analysed. The results indicate that the decarburisation process is accelerated, which results in a shorter treatment time of at least 3 min. Enlargement of the interfacial reaction area is considered to be the main decarburisation mechanism. Further study is recommended.

A three-dimensional mathematical model of compressible supersonic free surrounding jets from six convergent–divergent nozzles oxygen lance was developed based on the Reynolds averaged Navier–Stokes equations. The modelling results were validated by experiment. A comparison between the standard k∼ω turbulence model and realisable k∼ϵ was carried out, and it shows that the standard k∼ω turbulence model is superior in being able to depict the flow characters of multiple jets. The effects of nozzle inclination angle and operation pressure on jet flow characteristics and coalescence behaviour were investigated, and the mechanism of jet coalescence is discussed. The results show that coalescence patterns of six nozzle jets are strongly affected by the inclination angle but hardly by the operation pressure. When jets impinge on the melt surface in a BOF, the nozzle inclination angle plays also an important role in the splashing phenomena and the shape of cavity. It can be expected that when the nozzle inclination angle reduces from 17·5 to 10°, the cavities impinged by jets evolve from several scattered small craters to one large cavity. The change of jet coalescence pattern leads to different splashing patterns of the melt.

V containing spinel phase was successfully separated from vanadium slag by centrifugal casting. With the process parameters of G = 900 (where normal gravity G = 1), t = 20 min and T = 1557 K, almost all V containing spinel phase is enriched in the concentrate, while the tailing is made up of Fe₂SiO₄, Fe₂TiO₄ and Mn₂VO₄ phases. Under the hypothesis that the vanadium and silicon exist in the slag as V₂O₃ and SiO₂, the mass fractions of V₂O₃ and SiO₂ in the concentrate are 25·2 and 2·2%, while those of the tailing are 0·8 and 32·2% respectively. The recovery ratio of V in the concentrate is up to 97·4%, while the removal ratio of Si is 92·5% by centrifugal separation.

Non-stoichiometry influences both the thermodynamic and kinetic analyses of the iron oxide redox processes. The thermochemical data of iron oxide redox reactions in various textbooks are not consistent, and the kinetic characteristics are not well understood because of the non-stoichiometry. To clarify such confusions, some famous thermodynamic data are compared, and highly precise experimental work conducted for verification. It is shown that the thermodynamic data for the pure iron oxide reduction reactions from JANAF agree well with the experimental results; the eutectoid temperature of iron oxides was proven to be 576°C; Dieckmann’s defect model of magnetite was proven in good agreement with the experimental results only at high oxygen activities but not low oxygen activities; and the dependences of iron deficiency on Δwt-% (weight loss ratio) and Fe²⁺% (ferrous ratio) were calculated and experimentally verified in pure iron oxides reduction processes.