Influence of Alloying Elements on the Thermodynamic Properties of Titanium in Molten Steel
- PDF / 372,327 Bytes
- 10 Pages / 593.972 x 792 pts Page_size
- 32 Downloads / 247 Views
¼ 5:33ð0:84Þ;
eNi Ti ¼ 3:93ð0:51Þ;
eCu Ti ¼ 3:44ð0:69Þ
Through the investigation of titanium deoxidation equilibria in molten iron, the activity coefficient of titanium and the first-order interaction parameter between oxygen and titanium were determined as follows: cTi ¼ 0:0215ð0:00062Þ;
eTi O ¼ 160ð10Þ
Also, titanium deoxidation of molten 304 stainless steel was measured and compared with the calculated results using the determined interaction parameters. DOI: 10.1007/s11663-007-9075-9 The Minerals, Metals & Materials Society and ASM International 2007 I.
INTRODUCTION
IN order to control the microstructure of steels for the improvement of their mechanical properties, titanium is often added during the secondary refining process. Titanium forms titanium oxides and a nitride with dissolved oxygen and nitrogen, respectively, in the molten state, during cooling and solidification of the steel. When dispersed uniformly, these inclusions are known to be beneficial to grain refinement. Specifically, the effects of Ti2O3 or Ti3O5 inclusions on intergranular ferrite growth during the c/a phase transformation of iron have been intensively investigated in recent decades. Because these inclusions have a strong tendency to agglomerate in the molten steel, these agglomerated primary inclusions often cause nozzle-clogging problems or internal defects in the final product. Accordingly, controlling the formation of these inclusions remains an important issue, and knowledge of the thermodynamic properties of titanium in molten iron is needed for that purpose. However, the reported values of the interaction parameters of titanium in molten iron[1–13] are not sufficient for the various compositions of steel manufactured today. TAKESHI YOSHIKAWA, formerly Postdoctoral Researcher, Institute of Industrial Science, The University of Tokyo, Tokyo 1538505, Japan, is Assistant Professor, Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan. Contact e-mail: yoshikawa@ mat.eng.osaka-u.ac.jp KAZUKI MORITA, Professor, is with the Institute of Industrial Science. The University of Tokyo. Manuscript submitted December 24, 2006. Article published online August 4, 2007.
METALLURGICAL AND MATERIALS TRANSACTIONS B
In the present work, the titanium deoxidation equilibria in molten iron were investigated to determine the activity coefficient of titanium and the interaction between titanium and oxygen in molten iron, followed by clarifying the influence of alloying elements on the thermodynamic property of titanium in molten iron at 1873 K. Further, the titanium deoxidation equilibria in molten 304 stainless steel were measured and compared with the calculated results using the interaction parameters determined in the present study.
II.
EXPERIMENTAL
A. Principle-Determination Method of Interaction Parameters between Titanium and Alloying Elements in Molten Iron When the Fe-Ti-M(M: alloying element)-O melt is in equilibrium with both solid Ti3O5 and Ti2O3, the titanium activity o
Data Loading...
