钛合金管件高压气胀成形工艺研究进展

Research Progress of High Pressure Gas Forming for Titanium Alloy Tubular Components

高压气胀成形是在内高压成形基础上发展起来的管件成形技术,采用气体介质加载,可在高温下成形钛合金构件。以Ti-3Al-2.5V钛合金管材为实验材料,开展了矩形截面构件和大截面差构件高压气胀成形工艺研究,提出了气压阶梯加载方法和气压与轴向位移匹配的加载方法。结果表明,利用Ti-3Al-2.5V钛合金在一定温度和应变速率范围的应变和应变速率双硬化机制,采用合理的加载路径,能够消除开裂缺陷,以较高的效率实现钛合金异形管件的成形制造,并且构件壁厚相对均匀,形状和组织性能均可得到有效控制。

High pressure hot gas forming is a tubular components forming technology,which is developed from tube hydroforming.The complex Ti-alloy tubular components can be produced at elevated temperature using internal high pressure gas.In this paper,the high pressure gas forming of the Ti-3A1-2.5V square cross section and components with large diameter variation were introduced in details.The stepped gas loading path and the loading path with match of internal gas pressure/axial feeding were proposed for the two kind of components,respectively.The results show that the strain and strain rate hardening mechanism exist in the Ti-3A1-2.5V alloy in a certain range of temperature and strain rate.By controlling the loading paths,the crack defects can be avoided and the Ti-alloy complex tubular components with relatively thickness distribution can be produced with high efficiency.Meanwhile,the dimensional accuracy,microstructure and the mechanical properties of the tubular components can also be controlled.