Material Deformation Behavior in T-Shape Hydroforming of Metal Microtubes

Metals

Shoichiro Yoshihara¹  Kazuo Tada²  Ken-ichi Manabe²  Hajime Yasui³  Shigeki Mori⁴ 

[1] Department of Engineering and Design, Shibaura Institute of Technology, 3-9-14 Minato-ku, Tokyo 108-8548, Japan;Department of Mechanical System Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0397, Japan;Faculty of Engineering, Integrated Graduate School of Medical, Engineering, and Agricultural Sciences, University of Yamanashi, 4-3-11 Takeda Kofu-shi, Yamanashi 400-8511, Japan;Metal forming unit, Polytechnic University, 2-32-1 Ogawanishi-Machi, Kodaira-shi, Tokyo 187-0035, Japan;

关键词: microtube;    hydroforming;    t-shape bulging;    tube materials;    friction;    tube length;    micro hydroformability;    process window;    fe analysis;    microstructure;   

DOI  :  10.3390/met10020199

来源: DOAJ

【 摘 要 】

In this study, the material behavior in the T-shape microtube hydroforming (MTHF) of pure copper and stainless-steel SUS304 microtubes with an outer diameter of 500 µm and wall thickness of 100 µm was examined experimentally and numerically. This paper elucidates the basic deformation characteristics, the forming defects, and the forming limit as well as the effects of lubrication/friction and tube length. The hydroformability (bulge height) of the SUS304 microtube was shown to be higher than that of the copper microtube because of the high buckling resistance of SUS304. Good lubrication experimentally led to the high hydroformability of T-shape forming. The length of the microtube significantly affects its hydroformability. Friction resistance increases with increasing tube length and restricts the flow of the microtube material into the die cavity. By comparing the T-shape and cross-shape MHTF characteristics, we verified the hydroformability of the T-shape microtube to be superior to that of the cross-shape microtube theoretically and experimentally. In addition, the process window for T-shape MTHF had a narrower “success” area and wider buckling and folding regions than that for cross-shape MTHF. Furthermore, conventional finite element (FE) modeling without consideration of the grains was valid for MTHF processes owing to the many grains in the thickness direction.

【 授权许可】

Unknown