Effect of MnS precipitation on solute equilibrium partition coefficients in high sulfur steel during solidification
- PDF / 895,279 Bytes
- 11 Pages / 584.957 x 782.986 pts Page_size
- 103 Downloads / 210 Views
e solute equilibrium partition coefficients (ki) of C, Si, Mn, P, and S in high sulfur steel during the solidification process were investigated by the thermodynamic calculation. The effect of MnS precipitation on ki was explored. The results showed that the precipitation of MnS inclusion would influence the concentrations of solutes Mn and S, leading to the changing of ki. Due to the precipitation of MnS, the kC and kS decreased first and then increased with temperature decreasing, while kSi, kMn, and kP changed monotonously. The impacts of solidification temperature on kSi and kMn were greater than that on kC, kS, and kP. With the increase of S content, kC, kSi, and kP increased while kMn and kS decreased. Whereas, an opposite effect was found with the increase of Mn content. The order of influence extent by S and Mn contents was kSi . kS . kMn . kC . kP.
I. INTRODUCTION
The solute element would redistribute in solid and liquid phases at solidification front during the solidification process of alloys. This phenomenon is the intrinsic property of alloy solidification. The ratio of the solute concentrations between the solid and liquid phases is called the solute equilibrium partition coefficient (ki), and the solute segregation is mainly determined by ki during alloy solidification.1 In the simulation study of solute segregation, ki is an important characteristic parameter for characterizing the redistribution of solute elements at the solid–liquid interface,2 and its accuracy has a great influence on the prediction results of solute segregation.3 The solute equilibrium partition coefficient (ki) could be obtained by experimental4 and theoretical calculation,5,6 and the research objects mainly included Fe–C-based alloys,7,8 Ni based alloys,1 rare earth alloys,9 and so on.10 Hobbs3 and Sung4 applied a linear regression to solute partition coefficient for Ni-based alloys through experiment. Imai11 and Kagawa12 explored the effect of experimental temperature and component content on ki for Fe–C-based alloys. The experimental method to measure ki is intuitive and reliable. But, in fact, the solidification process of the alloy was difficult to achieve equilibrium13 and ki was varied with solidification temperature,14 which will increase the complexity of the experiment. The theoretical calculation method is generally by calculating the thermodynamic equilibrium of the
Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] DOI: 10.1557/jmr.2018.121
alloy solidification system. And its feasibility and accuracy has been verified by Kagawa et al.15 and Thomas et al.5 for Ni-based and Fe-based alloys with different components. During the solidification process of the alloy, ki was greatly influenced by the component, solidification path, and phase transition of the alloy system.4 Kagawa15 found that the coagulation temperature, solute concentrations, and the interaction between components all have a different effect on ki for Ni-based alloys. For Fe–Cbased alloys, studies were mainly focused
