抄録
In the previous paper, the deep-drawabilities of commercially pure aluminum sheets and mild steel sheets were studied in detail taking in account the change of r value during the processing. From the same viewpoint, this paper discusses the deep-drawability of commercially pure titanium sheets which have a crystal structure of hexagonal close-packed lattice different from aluminum and steel. The results are as follows : (1) The limiting drawing ratio, LDR, increases with the average r value (r^- value), but the rate of increase ΔLDR/Δr^- is relatively small. (2) The fracture strength correlates positively with the r^- value, as in theory, but the maximum drawing load remains constant irrespective of the r^- value, against theory. This relation can be connected with the result of (1), and resembles that of mild steel sheets. (3) The result of (2) can be well explained by the change of r^- value due to equibiaxial strain and pure-shear strain, i.e., strain path dependence of the r value. The changes of r value are confirmed by texture analysis.
