Abstract:
The influence of rare earth （RE） elements on the solidification process and eutectic transformation and mechanical properties of the high-V type cast, high-speed steel roll was studied. Test materials with different RE additions were prepared on a horizontal centrifugal casting machine. The solidification process, eutectic structure transformation, carbide morphology, and the elements present, were all investigated by means of differential scanning calorimetry （DSC） and scanning electron microscopy energy dispersive spectrometry （SEM-EDS）. The energy produced by crack initiation and crack extension was analyzed using a digital impact test machine. It was found that rare earth elements increased the tensile strength of the steel by inducing crystallization of earlier eutectic γ-Fe during the solidification process, which in turn increased the solidification temperature and thinned the dendritic grains. Rare earth elements with large atomic radius changed the lattice parameters of the MC carbide by forming rare earth carbides. This had the effect of dispersing longpole M C carbides to provide carbide grains, thereby, reducing the formation of the gross carbide and making more V available, to increase the secondary hardening process and improve the hardness level. The presence of rare earth elements in the steel raised the impact toughness by changing the mechanism of MC carbide formation, thereby increasing the crack initiation energy.[著者文摘]
Key words:
eutectic carbide; impact toughness; differential scanning calorimetry; high-speed steel roll; rare earths
收稿日期: 2006-11-29
修订日期: 2007-05-16
基金资助:
Project supported by ＂863＂ Project （2006AA03Z532） and the National Natural Science Foundation of China （NSFC 50341050）
作者简介:
Wang Mingjia （1960-）, Ph. D, Professor Coresponding author（E-mail： mingka@ysu.edu.cn）