Differential Calculation Model for Liquidus Temperature of Steel

Abstract

The liquidus temperature of steel is greatly affected by its chemical composition; therefore, the value of the liquidus temperature can vary among different types of steel. In this study, on the basis of the concept of differentiation, the Fe‐i binary phase diagram is analyzed using Photoshop image processing software. The effects of eleven common alloying elements (C, Si, Mn, P, S, Ca, Ni, Cu, Cr, Nb, and Mo, whose content is between 0%∼4%) on the melting point of pure iron are analyzed. This analysis proves the following assumption to be incorrect: the relationship between the change in liquidus temperature and the content of element i is a linear relationship; this assumption is the basis of traditional liquidus calculation models. A new model for calculating the liquidus temperature of steel is established in this study. As compared to data from other literature, the model proposed in this paper has good generality and the calculation error of the liquidus temperature of steel is between −3 and 4 °C, which is acceptable. A statistical analysis of the experimental data for different steel grades (obtained from Laiwu Special Steel) using the developed model showed that 87.2% of the absolute deviation values of the temperature are within 4 °C. This result shows the model to be both reasonable and credible.

Effects of Alloying Elements on the Ferrite Potential of Peritectic and Ultra-Low Carbon Steels

“…However, Wang et al From Fig. 9, it is evident that the calculated values correlate very well with those predicted by Wang et al 8) (the maximum deviation is <10°C). This difference might be due to two reasons.…”

“…This difference might be due to two reasons. First of all, Wang et al's 8) correlation does not take into account the effects of N while the alloys selected for calculations contained N in the range 40-100 ppm (Table 1). Nitrogen is expected to decrease Tliq still further but its effect cannot be quantified since there is no literature available on the effects of N on Tliq.…”

“…Nitrogen is expected to decrease Tliq still further but its effect cannot be quantified since there is no literature available on the effects of N on Tliq. Secondly, the equation by Wang et al 8) have been derived by considering simple Fe-i binary systems while the present calculations have been done for actual pseudo binary systems containing all the alloying elements. Thus, the equation predicted by Wang et al 8) neglects the effects of interaction between different ele- ments.…”

“…Secondly, the equation by Wang et al 8) have been derived by considering simple Fe-i binary systems while the present calculations have been done for actual pseudo binary systems containing all the alloying elements. Thus, the equation predicted by Wang et al 8) neglects the effects of interaction between different ele- ments. A correction factor has later been introduced into the proposed equation to account for the interactions but the use of a constant term seems unreasonable because the interaction terms are expected to be strong functions of compositions.…”

Effect of Elements on Peritectic Reaction in Molten Steel Based on Thermodynamic Analysis

“…To validate the calculation results, we derived the liquidus and solidus temperature from the calculated phase diagram and comparing them with the literature data, [7][8][9][10] as shown in Fig. 6.…”