| Title |
Pesearch Paper / Mechanical Behavior : Carbide Precipitation and High Temperature Strength of Hot Rolled Containing Cr and Mo Fire Resistant Steels |
| Authors |
이원범(Won Beom Lee),홍승갑(Seung Gab Hong),박찬경(Chan Gyung Park),김기호(Ki Ho Kim),박성호(Sung Ho Park) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Abstract |
The effects of Mo addition on both the precipitation kinetics of Nb carbide and the high temperature strength have been investigated in hot rolled HSLA steels containing Cr and Mo. These steels were hot-rolled and coiled at 550, 600, and 650℃ respectively. Microstructural analysis of the carbides has been made using Field-Emission-Gun TEM attached EDS. The steels containing Cr and Mo exhibited higher strengths both at room temperature and high temperature(600℃) in comparison to the conventional HSLA steel containing only Cr. Refined bainitic structure could be obtained in the Cr-Mo contained steels due to the increase of hardenability and the fraction of bainitic phase increased with the increase of Mo content. TEM observations revealed that the Cr-Mo contained steels exhibited fine($lt;10 nm) and uniformly distributed Nb carbides, while the Cr contained steel exhibited coarse and sparsely distributed. The EDS analysis also indicated that the fine carbides was composed of complex form of carbide (Nb, Mo)C and the Mo content was higher in the finer carbides. The results clearly indicated that the addition of Mo affected the initial stage of Nb carbide precipitation. That is, Mo caused both transformation hardening and the uniform distribution of fine Nb carbides. |