INFLUENCE OF SULFUR AND MN S RATIO ON THE HOT DUCTILITY OF STEELS DURING CONTINUOUS-CASTING/

The influence of S and (Mn/S) on the crack susceptibility of continuou s casting steels was studied. It is theoretically demonstrated that th ere is a critical value of the (Mn/S) ratio, (Mn/S)c, under which a hi gh susceptibility to cracking, during casting or deformation of as-cas t material, is expected. The value of (Mn/S)c increases as the S conte nt of the steel decreases. Based on literature data and results from r olling continuous casting billets the following experimental equation has been found: (Mn/S)c = 1.345 . S-0.7934. A high similarity between this experimental equation and the theoretical one is achieved. A comp arison between the equation found and previous expressions from litera ture was carried out. The MSC index as the ratio between the (Mn/S) ra tio of a steel and the corresponding critical one was defined. The MSC index is a useful tool for the analysis of experimental results from literature.