Optimum Temperature of Hot Rolled Reinforced Bars at the Cooling Bed

Maintaining high accuracy temperature measurements at the cooling section is essential in order to attain the overall quality of the finished product, and to realise the correct properties. A series of "heat" numbers or batches of molten steel from an Electric Arc Furnace (EAF) for the production of Y12 mm reinforced bars (rebars) were observed at a steel plant to establish the optimum temperature of the rebar at the cooling bed. The casting was done in billet casters and the billets with 100mm×100mm cross-section were then hot rolledto the required size. The finish rolling temperature was between 850-900°C at 11m/s rolling speed. There bars were water quenched in the water box, and lastlysent for cooling on the cooling bed. Tensile tests and bend tests were carried out on rebars every after 15 minutes during the production to ensure that correct mechanical properties were achieved. It was observed that 850°C was the best finishing temperature and 250 °C was the optimum temperature at the cooling bed after equalization. The results for the tensile tests and microstructures were consistent with prescribed standards. The rebar samples were all of low carbon steel.