チタン板の深絞り性に関する研究

抄録

The deep drawability of titanium sheets were estimated using the single blank deep drawing method. The results obtained may be summarized as follows:
(1) The limit of drawing ratio (L.D.R.) increases at a nearly constant \barn with increase in \barr. When \barr is kept constant (∼3.5), the result that L.D.R. increases with increase in \barn was obtained. But this seems outwardly from the fact that \barn is related to grain size, and that the specimen with a different grain size workhardens in a different way.
(2) As for the r values of the specimen with the main component of the texture (0002)±35°TD ⟨1010⟩, r₉₀>r₄₅>r₀. The trend of the planar anisotropy of the r value could be explained from the calculation based on the Schmid factor for prismatic slip to the above texture. Their absolute values, however, should be obtained by applying the method proposed by Nagashima et al. to all the possible slip system and twin systems.
(3) It is possible in the cold rolled state to obtain the sheet which has some amount of the (0002) texture component. But when annealed, the basal pole inclined gradually at 30°∼35° to the transverse direction. Therefore, one could not get the texture suitable for texture hardening by the adjustment of the final rolling reduction and the final annealing temperature.
(4) The fracture of the cup wall occurred at 0° position when the titanium sheet was deep drawn, which could be explained by Yamada’s analysis.
(5) The deep drawability of titanium sheets could not be estimated from the X value proposed by Yoshida et al. because in titanium the way of workhardening, the n value and the \barn value vary with grain size.