Abstract
The influence of cooling rate on the hot ductility of plain C-Mn steels containing 0.1–0.7%C has been examined for tensile specimens tested in the temperature range 1000–550°C. Increasing the cooling rate from 10 to 60 K min−1 in all cases caused the ductility to deteriorate. This deterioration was found to be associated with the presence of a finer sulphide distribution in the ferrite surrounding the austenite grains, as well as a reduction in the thickness of the ferrite covering. Decreasing the strain rate from 3 x 10−3 to 5.3 × 10−4 S−1 led to a smaller influence of cooling rate. However, ductility was always poorer at the lower strain rate as grain boundary sliding was enhanced. Evidence is also submitted to indicate that MnS inclusions can encourage the production of deformation induced ferrite, leading to an earlier recovery in ductility at the low temperature end of the trough in the hot ductility curve.
Get full access to this article
View all access options for this article.