Study On Hot Extrusion of Tubes

• Main Authors: Liao Chiao-shun, 廖招順
• Other Authors: Shiang Su-Hai
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/71692506555857508449

碩士 === 國立臺灣科技大學 === 機械工程研究所 === 83 === In this study, a numerical simulation model for forward hot extrusion process of tube has been developed. This numerical si- mulation model combines the upper bound method with the finite difference method, and it is proposed to predict the deformation behaviors and forming load during the extrusion process. Besi- des, in order to investigate the influence of process variables to extrusion process, mechanical property tests of the extruded tube are performed. The Kinematically admissible velocity field of tube is de- rived , the energy consumption can be calculated, and metal fl- ow pattern can be obtained.Then, the finite difference method is applied to predict the temperature distribution in the billet ,and in the interface of billet and die during the extrusion process. For the purpose of examining the availability of this numerical simulation model, A6061 tubes are extruded at various temperatures. The metal flow is observed on macro etched section of the discard remained in the container, and the charge welding seams in the cross-section of the extruded tubes are observed by macro etching. The strength of welded portions of extruded tube is evalua- ted by the expanding and flattening tests. The expanding ratios of extruded tubes are compared with those of seamless tubes pro- duced by machining the same materials. It is found that the st- rength of the extruded tubes is comparable to the tear streng- th of billets. From the experimental and analytical results, the optimal tube extrusion conditions can be found.