Experimental and Numerical Research on Deformation Behavior of Thin-Walledand Large Expansion Ratio Guide Vane Liner in Hydroforming Process

Pengzhi Cheng¹,Lihui Lang¹,Yulong Ge¹, Shangwen Ruan¹, Xinmin Duan²,Tianwei Shao² ¡¼JZ¡½¡¼

(1.School of Mechanical Engineering £¦ Automation, Beihang University, Beijing 100191, China;2.AVIC Shenyang Liming Aero-Engine (Group) Co., Ltd., Shenyang 110043, China)



Abstract:

Some tube hydroforming process tests and further research work were conducted to manufacture hollow guide vane liners (made of super alloy GH3030).The relative thickness (t₀/OD) of the tubular blank is approximately 0.01,and the maximum expansion ratio (Dª­ª«maxª«/OD) of the needed part is more than 40£¥, and the length to diameter ratio of the expansion regionis more than 3.0. It is very hard to manufacture this kind of ultra-thin-wall, curved axis and large expansion ratio tubular part without fracture and wrinkles. The success of the process is highly dependent on useful wrinkles with appropriate internal pressure and axial feeding. A simplified finite element model and a theoretical model are used for detecting the deformation behavior and forming laws. Further study results demonstrate that the useful wrinkles do not appear at the same time and middle-wrinkles need bigger axial force than tube-end-wrinkles and feeding-wrinkles. The wrinkles can transfer bigger axial force after its wave peak has come into contact with the die inner surface. The thickness thinning rate of the element at the peak is bigger than that at the trough.With the increase of the axial and hoop stress ratio, the critical buckling stress also increases. Microstructure examination results show that the grain size in the maximum thinning zone has been stretched and refined after the large deformation and annealing treatment. The process is feasible and the finished part is qualified.

Key words:  tube hydroforming  super alloy  ultra-thin-wall  large expansion ratio  useful wrinkle  plastic buckling  critical buckling stress

DOI£º10.11916/j.issn.1005-9113.2015.04.001

Clc Number:V221+.3

Fund: