The effect of phosphorus on the deep drawability of cold-rolled steel sheets was studied by changing carbide morphology before cold rolling and heating rate in annealing. The main results obtained are as follows. (1) In slow-heating annealing, phosphorus improves the deep drawability in the presence of solute carbon and deteriorates the deep drawability in the absence of carbon. (2) In the presence of coarse-carbide, increase in heating rate improves the deep drawability of low-phosphorus steels, but deteriorates that of high phosphorus ones. These results are discussed in detail, taking account of the γ-value and the texture.
