| 摘要 |
PURPOSE:To manufacture a pipe having non-circular sectional form made of alpha+beta type titanium alloy at high dimensional accuracy which so far considered impossible by utilizing superplasticity phenomenon in alpha+beta type titanium alloy. CONSTITUTION:An alpha+beta type titanium alloy flank pipe is sealed by end plates 2, 3 and an inner sending pipe 4 is pressure contacted to the end plate 3 and a blank pipe assembly 5 is manufactured. This is inserted into a non-circular mold 6, and the blank pipe assembly 5 and non-circular mold 6 are heated by a heating device in a vacuum furnace 7. At the same time, high pressure inert gas is introduced into the flank pipe 1 through the inner sending pipe 4 to deform the blank pipe 1. At this time, the temperature of heating and distortion speed of deformation are made to temperature and distortion speed that hold the blank pipe 1 within the range of superplasticity proper to the material quality of the blank pipe 1. Thus, an alpha+beta type titanium alloy pipe having non-circular sectional form is manufactured. |
