Ti-6Al-4V板の機械的性質におよぼす熱間圧延温度およびクロス圧延の影響

Abstract

Ti-6Al-4V alloy was hot rolled in the β and α+β ranges, and the effects of cross rolling in the β range, rolling temperature and cross rolling in the α+β range on the tensile properties, bend properties, microstructures, anisotropy of hardness and the textures were examined.Hot rolling in the β range was carried out at the early rolling process. At the finishing rolling process the finishing temperature was fixed at 800°C by taking the amount of β-phase into consideration and the heating temperature was varied from 900 to 950°C. Tensile properties, bend properties, microstructures, hardness and textures were observed in the specimens subjected to the following processes: [(a)] straight rolling in the β range, followed by straight rolling in the α+β range [(b)] straight rolling in the β range, followed by cross rolling in the α+β range [(c)] cross rolling in the β range, followed by straight rolling in the α+β range [(d)] cross rolling in the β range, followed by cross rolling in the α+β range The results are as follows:(1) In this alloy the alignment of [0002] axes are observed not only in the normal direction but also in the rolling and transverse directions of the sheet. The sheet which was straight-rolled in the α+β range shows a higher pole intensity in the transverse direction than that in the rolling direction and a large planar anisotropy in the yield and tensile strengths. On the other hand, the sheet which was cross-rolled in the α+β range shows a nearly equal intensity in the rolling and transverse directions and little planar anisotropy in the yield and tensile strengths.(2) Thus, an adequate manufacturing process for this material is concluded to be a process that involves cross rolling at an appropriate temperature in the α+β range.