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-350°C 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 850°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 (RAvalues greater than 70%) at higher strain rate (6.5/s).