This paper deals with electric arc furnace off‐gas heat recovery and first experiences with a testing plant. The testing plant based on molten salt as heat transfer fluid was installed inside the existing off‐gas system of a German mini mill. Targets of the testing plant are to evaluate tube materials and to measure the influence of hot corrosion and dust settlement. First experimental results are presented. Besides experimental measurements numerical simulations were performed. A process simulation was necessary to describe process dynamics. A computational fluid dynamic simulation of the testing heat exchanger was done to calculate the off‐gas flow profile around the heat exchanger.

During continuous casting processes lubrication between mould and strand shell is very important for reaching and maintaining a good surface quality of both the as-cast strand and the finished product. The lubrication is influenced by the properties of the mould powder but also by the friction forces caused by the periodic movements of mould and the descending strand shell. In the present research measurements were carried out to investigate the friction forces during 150 mm sq. billet casting of different steel grades using mould powder or granules and submerged entry nozzles. The friction forces reached values up to 6 kN. Since friction forces are depending on upward and downward movements within the mould-strand-system, the evaluation of a rheogram shows the typical change of pressure and tension. Maximum friction forces arise during the positive strip time of the rising mould, introducing tensions and cracks in the as-cast strand. On the other hand lowest frictions forces are generated by the descending mould within the negative strip time leading to the healing of faults in the as-cast strand. These industrial experiments indicate a correlation between friction forces and surface quality of as-cast strands.Keywords: frictions forces, tension and pressure, mould, strand shell, positive and negative strip time, friction force Wing, surface quality, healing time, breakout, quality of the as-cast strand. the negative and positive strip time of the sinusoidal movement. Various research works [2-23] had been published about this topic. In this investigation intensive measurements were carried out to determine the friction forces at a billet caster with the strand size of 150 mm sq.