Material Deformation Behavior in T-Shape Hydroforming of Metal Microtubes
Material Deformation Behavior in T-Shape Hydroforming of Metal Microtubes
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DOI：
10.3390/met10020199
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发表时间：
2020-01
期刊：
影响因子：
2.9
通讯作者：
H. Yasui;S. Yoshihara;S. Mori;K. Tada;K. Manabe
中科院分区：
文献类型：
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作者：
H. Yasui;S. Yoshihara;S. Mori;K. Tada;K. Manabe
本文对外径为500µm、壁厚为100µm的纯铜和不锈钢SUS304微管的t形微管液压成形过程中的材料行为进行了实验和数值研究。本文阐述了管材的基本变形特性、成形缺陷、成形极限以及润滑/摩擦和管材长度的影响。由于SUS304具有较高的抗屈曲性，SUS304微管的流体成形性（凸起高度）比铜微管高。实验表明，良好的润滑条件使t形成形具有较高的流体成形性。微管的长度对其流体成形性有显著影响。摩擦阻力随微管长度的增加而增加，限制了微管材料进入模腔的流动。通过对比t形微管和十字形微管的流体成形特性，从理论上和实验上验证了t形微管的流体成形性能优于十字形微管。此外，与十字形MTHF相比，t形MTHF的工艺窗口具有更窄的“成功”区域和更宽的屈曲和折叠区域。此外，由于厚度方向上晶粒较多，不考虑晶粒的传统有限元模型对MTHF过程是有效的。
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.