The transport of pig iron from the blast furnace to the steel plant is performed in so-called torpedo ladles. Finite element models of ladles have been developed in order to determine an accurate temperature loss of the pig iron and to calculate the occuring mechanical stresses as well as a possible opening of joints at the hot face and failure of refractories. The results showed possible mechanisms of wear. Joints, expansion allowances and refractory mortars have to be part of the model in the case of thermomechanical analyses. The temperatures of the pig iron are calclated for each of the first 15 heats and show a decreasing temperature loss with the number of heats. The loss depends on working lining material and thickness. The logistic boundary conditions are another decisive factor. Choosing the parameters idle time and lining thickness combined with thermal material data properly allows a minimisation of heat loss in the pig iron. If the estimated idle time is short, then a thicker lining is economically more advandageous. This is due to its insulating effect. A long idle time demands a ladle with lower heat capacity and smaller lining thickness. On account of different durabilities of the refractory linings, savings in the energy costs could be counterbalanced by shorter operation times and higher costs for relining and refractory material. Mechanical calculations indicate that changes of lining thickness (i. e. steps in the shape of the hot face) cause discontinuous wear near a step in the thicker part of the lining. A possible opening of joints on the hot face shows a correlation with material properties, for example the hot compressive strength.
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