A Study of the Re-Solidified Structures of Electro-Discharge Machined Ductile Iron

• Main Authors: Kuang Shing Chen, 陳光星
• Other Authors: T.S.Lei
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/61250962656217618107

碩士 === 國立臺灣科技大學 === 機械工程系 === 92 === This research is aimed to investigate the characteristics of re-solidified structures of electro-discharge machined ductile iron. The re-solidified layer of the electro-discharge machined work pieces were ground, polished and etched to examine its solidification features by using FE-SEM and EPMA. The results show that: (1) the re-solidified white layer of ductile iron is the re-solidified structure of the re-molten matrix with a thickness about 30μm~40μm and a microstructure of fine dendrites; (2) the thickness of the white layer of high carbon tool steel is about 20∼30μm with a microstructure of fine dendrites; (3) for high chromium white iron, its white layer, about 20∼30μm thickness, shows more features on the surface topography and cross section structure of high has special features, and is discontinued from the blocky carbide; (4) The solidifying procedure of the white layer belongs to a category rapid solidification with a cooling rate of 5x106℃/s.