Adrian Normanton

At the thin slab caster of Tata Steel, IJmuiden, mild cooling mould powders were introduced with the aim to control the mould heat transfer during casting. These mild cooling mould powders are characterised by specific values of basicity, solidification point and chemical composition. Application of these mould powders resulted in a redistribution of mould heat transfer during casting, i.e. a reduced and more stable mould heat transfer in the critical upper part of the mould and an increased mould heat transfer in the lower part of the mould. The average mould heat transfer and hence the shell thickness at mould exit are comparable to the standard powder. The application of mild cooling mould powders also resulted in improved solidification behaviour of the steel shell. A thinner chill zone with smaller thickness variations was observed. Furthermore, it was found that the mould taper required optimisation to match the changes in shrinkage behaviour to ensure uniform solidification. The use of mild cooling powders was observed to give an increase in mould friction. Mould thermal monitoring indicated that the solid slag films fractured (sheeting) in the upper part of the mould. However, no operational problems were reported, which indicate that the first 200 mm under the steel meniscus is essential for initial solidification and for the formation of a homogeneous steel shell. All these findings can be understood by considering the crystallisation properties of the mould slag, which include the cooling rate. Mild cooling has been shown to provide uniform heat transfer and adequate lubrication for high speed thin slab casting.

Section: Mild Cooling During Thin Slab Castingmentioning

confidence: 89%

Section: Mild Cooling During Thin Slab Castingmentioning

confidence: 99%

“…Based on the condition of the DSP caster and the stability of the casting process, increased casting speeds, i.e. .6?0 m min 21 , were not possible.…”

Section: Mild Cooling During Thin Slab Castingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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et al. 2012

A new approach was made to model the dephosphorisation process in a 300 tons basic oxygen furnace converter with three argon gas inlets. The main feature of the new approach was to utilise the velocity vectors obtained by computational fluid dynamics (CFD) simulation in a standalone model. The CFD simulation was carried out using commercial software COMSOL Multiphysics. In the standalone model, the steel melt domain was sliced into 1000 cells. The calculated velocity vector in each cell was assumed constant. Based on the imported velocity vectors from the CFD calculation, the mass transfer of carbon and phosphorus was calculated by taking into account the slag-metal reactions. The mass exchange between slag and metal was considered to be dominated by the metal droplet formation due to the oxygen jet. The convergence of the model calculation and the promising comparison between the model prediction and the industrial data strongly suggested that the proposed approach would be a powerful tool in dynamic process control. As a preliminary step, the model only simulated the process after the formation of slagmetal-gas emulsion. Note that the present work is intended to establish a structure of the model. More precise descriptions of other process aspects need to be included before the model can be practically employed in a dynamic controlling system.

Effect of casting parameters on sticker breakout and its propagation behaviour during slab continuous casting

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Wang

Yao

et al. 2014

A sticker breakout is a significant occurrence which not only disturbs steady state casting but also reduces plant productivity and efficiency. Optimising the casting parameters and increasing the accuracy rate of breakout prediction systems are two effective measures for reducing breakouts. In the present paper, plant data were collected and the influence of casting parameters such as slab dimension, casting speed and mould level on sticker breakouts were analysed, especially the effect of heat flux. In addition, sticker propagation behaviour characteristics, including vertical velocity, horizontal velocity and propagation angle, were investigated by measuring the temperature of the mould copper plates. These results provide a reference for optimising the casting parameters and enhancing the accuracy of breakout prevention systems.