Abstract
The effects of Mn-S-O contents balance, carbide morphology, and size of MnS precipitate on the deep drawability of cold rolled steel sheet was studied.
The obtained results are as follows.
(1) In the case where the K-value [=Mn (%)-55/32 S (%)-55/16 O (%)] is about -0.1, the deep drawability of box annealed sheet is improved by low temperature coiling, because S remains in solution in hot bands. The deep drawability of the continuously annealed sheet is improved by high temperature coiling because S precipitates as sulfide. When the K-value lie between 0 and 0.1, these phenomena do not occur in low C rimmed steel sheet.
(2) The improvement of the deep drawability of low C rimmed steel sheet by high temperature coiling in hot bands is not attributed to the growth of MnS precipitate but to the coarsening of carbide.
