THERMODYNAMIC CALCULATION OF SOLUTE CARBON AND NITROGEN IN NB AND TI ADDED EXTRA-LOW CARBON-STEELS

被引:45
作者
AKAMATSU, S
HASEBE, M
SENUMA, T
MATSUMURA, Y
AKISUE, O
机构
[1] KYUSYU INST TECHNOL,FAC ENGN,TOBATA KU,KITAKYUSHU,FUKUOKA 804,JAPAN
[2] NIPPON STEEL CORP LTD,YAWATA RES & DEV LAB,TOBATA KU,KITAKYUSHU,FUKUOKA 804,JAPAN
关键词
EXTRA-LOW CARBON STEEL; INTERSTITIAL FREE STEEL; THERMODYNAMICS; PRECIPITATION; CARBONITRIDE; PHASE DIAGRAM; PHASE STABILITY; SOLUTE CARBON AND NITROGEN; THERMO-CALC;
D O I
10.2355/isijinternational.34.9
中图分类号
TF [冶金工业];
学科分类号
0806 ;
摘要
To predict solute carbon and nitrogen in Nb and Ti added extra-low carbon steels quantitatively, the phase stability of the carbonitride in austenite and/or ferrite has been calculated by using Thermo-Calc software to which some thermodynamic parameters were added for the Fe-Nb-Ti-C-N system. It has been confirmed that the (Nb,Ti)(C,N) phase has a miscibility gap island, which is predicted from the tieline sets between TiN-like and NbC-like phases, and the phase can be revealed in the ferrite region, that is, duplex precipitates coexist in the matrix of ferrite in the equilibrium state, whereas only one Ti N-like phase precipitates in the austenite region. As a consequence of the above phase stabilities, it has been predicted that each amount of nitrogen and carbon in solution changes only in the austenite region and the ferrite region, respectively. A quasi-equilibrium precipitation as a two-step heat-treatment has also been demonstrated.
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页码:9 / 16
页数:8
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