The simulation of multi-pass hot working of titanium through processing map

• Main Author: 陳欩仰
• Other Authors: Chang-Pin Chou
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/92387187619860009701

碩士 === 國立交通大學 === 機械工程系 === 90 === Titanium is one of the worthful and high-performance materials. Several special characteristics are obtained through appropriate processing parameters of hot working during forming. Because most processes need multi-pass hot working, the major parameters such as temperature and strain rate have to be controlled strictly. This research was to explore the single-pass and two-pass hot compression of Ti-6Al-4V (ELI) using Gleeble. The experimental conditions included five temperatures and five strain rates with ten seconds unloading time. The difference of the two processes were compared and analyzed through the simulation of processing map. The results of this study show that most of the stresses with two-pass are higher than that with single-pass at high strain rate. And the peak efficiency of power dissipation for the two-pass is higher too. There are three unstable regions in both processing maps. The temperature range in two-pass processing map is wider, and its temperature was higher around α+β phase field. The developed processing map is well consistent with the observed microstructure. In the single-pass processing map with a true strain of 0.5, 50％ peak efficiency can be obtained around 900-960℃ and 0.001-0.003s-1. While 60％ peak efficiency can be obtained in the two-pass processing map around 940-975℃ and 0.001-0.002s-1. Thus, it is helpful to choose more accurate parameters of process around the stable region by using multi-pass processing map at the actual working