Dissolving of Nb and Ti carbonitride precipitates in microalloyed steels

Wenjin Nie, Shanwu Yang, Shaoqiang Yuan, and Xinlai HeMaterials Science and Engineering School, University of Science and Technology Beijing, Beijing 100083, China

摘 要：<正> The dissolving behaviour of Nb and Ti carbonitride precipitates in microalloyed steels during isothermal holding at 1300℃ was investigated by Transmission electron microscopy （TEM） and energy dispersion x-ray spectrum （EDX）. It was found that all precipitates in Nb-Ti microalloyed steel are （Nb, Ti）（C, N）. With holding time increasing, the atomic ratio of Nb/Ti in precipitates decrease gradually. These precipitates still existe even after holding for 48 h at 1300℃while Nb（C, N） precipitates dissolve away in Nb microalloyed steel only after 4 h at the same temperature. These results show that formation and thermostability of precipitates are considerably influenced by interaction between Nb and Ti.

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