Hot ductility study on high P and Cu containing low alloy steel

Six numbers of laboratory heats of 25 kg each were made using a high frequency induction melting furnace. Various elements, viz, Ni, Cu, P and Si in the range of 0.01-2.0%, 0.22-0.47%, 0.12-0.19% and 0.40-0.86%, respectively were added during melting of the steels. Carbon and sulphur contents were kept at low levels, i.e., 0.05-0.087% and 0.005-0.01%, respectively. Hot tensile tests were carried out using Gleeble-3500C simulator, which revealed reduction in area in excess of 70% at all deformation temperatures and at slow strain rate (0.005/s) testing conditions for all the experimental steels excluding low Si (0.40%) containing steels. The lower hot ductility (RA value <30%) of these steels resulted in brittle failure at 8500 C, which corresponds to the temperature experienced during straightening operation of continuous casting. On the other hand, hot ductility of low Si containing steels was significantly increased (RA values greater than 70%) at higher strain rate (6.5/s).