Nature of large (Ti, Nb)(C, N) particles precipitated during the solidification of Ti, Nb HSLA steel
来源期刊:International Journal of Minerals Metallurgy and Materials2007年第2期
论文作者:Hae-Geon Lee
文章页码:112 - 117
摘 要:To investigate the microsegregation phenomena and complex (Ti, Nb)(C, N) precipitation behavior during continuous casting, a unidirectional solidification unit was employed to simulate the solidification process. The samples of Ti, Nb-addition steels after unidirectional solidification were examined using field emission scanning electron microscope (FE-SEM) and electron probe X-ray microanalyzer (EPMA). In such specimens, dendrite structure and mushy zone can be detected along the solidification direction. It shows that the addition of titanium, niobium to high-strength low-alloyed (HSLA) steel results in undesirable (Ti, Nb)(C, N) precipita- tion because of microsegregation. The effect of cooling rate on (Ti, Nb)(C, N) precipitation was investigated. The composition of large precipitates was determined using FE-SEM with EDS. Large (Ti, Nb)(C, N) precipitates could be divided into three kinds according to the composition and morphology. With the cooling rate increasing, Ti-rich (Ti, Nb)(C, N) precipitates are transformed to Nb-rich (Ti, Nb)(C, N) precipitates.
Hae-Geon Lee
摘 要:To investigate the microsegregation phenomena and complex (Ti, Nb)(C, N) precipitation behavior during continuous casting, a unidirectional solidification unit was employed to simulate the solidification process. The samples of Ti, Nb-addition steels after unidirectional solidification were examined using field emission scanning electron microscope (FE-SEM) and electron probe X-ray microanalyzer (EPMA). In such specimens, dendrite structure and mushy zone can be detected along the solidification direction. It shows that the addition of titanium, niobium to high-strength low-alloyed (HSLA) steel results in undesirable (Ti, Nb)(C, N) precipita- tion because of microsegregation. The effect of cooling rate on (Ti, Nb)(C, N) precipitation was investigated. The composition of large precipitates was determined using FE-SEM with EDS. Large (Ti, Nb)(C, N) precipitates could be divided into three kinds according to the composition and morphology. With the cooling rate increasing, Ti-rich (Ti, Nb)(C, N) precipitates are transformed to Nb-rich (Ti, Nb)(C, N) precipitates.
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