Review on the Viscosity of Iron-based Melts in Metallurgical Process

Abstract

Low-carbon metallurgy is a critical issue for the world in the 21st century and improving production efficiency is one of the main ways to resolve this problem. Ironbased alloy runs through the whole process of metallurgy, and the viscosity properties of melt is of great significance on the process of reaction, transportation and solidification casting, which is one of the constraints on production efficiency. The research progress of the viscosity of iron-based melt is summarized from the aspects of measurement methods, influencing factors and prediction models in this paper. It is briefly concluded that the oscillating method is the most widely used measurement method of iron-based melts and pointed out that the interaction between the components and the formation of inclusions will have a significant effect on the viscosity of ironbased melts. And the three semi-empirical models derived from the Andrade equation can be applied to the viscosity prediction of molten iron as the pre-revised basic equations with greater precision. Then the direction of iron-based melt viscosity 2 research in the future is prospected at last.

The Minima of Viscosities

“…The extreme increase in temperature can additionally cause the dissociation of molecules and ionisation, and leads to the transformation of matter to a plasma state, with possible intermediate condensed phases such as the condensed Rydberg matter, the rheological behaviour of which is unknown [59][60][61][62], although these can be of practical use to validate the TB approach to viscosity and its modification, applying the above concept of effective masses. Finally, we note that the Eyring-Kaptay (EK) equation used here to find the temperature T vm was extended from the temperature range, where its correctness was confirmed by the experiment [6,63], to the range where its validity may be questionable; therefore, Equation ( 3) is an approximate assessment of the crossover temperature T vm . Accounting for the fact that the DDO model of viscosity gives a twice-smaller value of T vm = E a /R [10,11], we can admit that in the experiment, the viscosity minima could be expected to be within the interval from E a /R to 2E a /R, in any case being directly proportional to the activation energy of fluid flow at high temperatures.…”

Rheological Characteristics of Fe–C–Cr(Ni) Alloys

“…Specifically, Chapman determined it to be approximately 6.5 mPa·s [ 18 ], Battezzati 5.5 mPa·s [ 19 ] and Brooks 6.93 mPa·s [ 16 ]. However, even in the case of binary and ternary systems, the viscosity of iron-based alloys can vary by units of mPa·s, with the addition of alloying elements in the order of tenths to units of percent [ 20 , 21 ]. Furthermore, it is worth noting that the effect of the same dissolving element on viscosity may differ for binary and multicomponent melts, and it can be assumed that specific interactions between the components change the patterns of their effect on viscosity [ 22 ].…”