Solubility of Low-Melting and Low-Boiling Elements in Iron-Base Alloys

Abstract

The solubility of bismuth and lead in liquid ternary alloys of iron with silicon, nickel, manganese and chromium is experimentally determined at 1600 °C. Maximum concentrations of alloying elements were 24.14 % Cr, 5.02 % Mn, 2.78 % Si and 12.68 % Ni for bismuth and 15.26 % Cr, 5.53 % Mn, 15.12 % Si and 15.01 % Ni for lead.

Experiments were carried out in a high-pressure furnace set at the General Metallurgy Department of the South Ural State University. Bismuth and lead were dissolved in liquid iron alloys through the gas phase.

Manganese and nickel increase bismuth solubility, silicon decreases it, and the effect of chromium is not too noticeable. On the other hand, silicon and chromium decrease the solubility of lead and manganese and nickel increases it. First and second order interaction parameters for bismuth and lead with the alloying elements were determined. First-order interaction parameters at 1600 °C are equal to eBi(Si) = 0.1148; eBi(Mn) = –0.0512; eBi(Ni) = –0.052; eBi(Cr) = 0.0011 and ePb(Si) = 0.0372; ePb(Mn) = –0.066; ePb(Ni) = –0.0071; ePb(Cr) = 0.0039. Second-order interaction parameters are equal to rBi(Si) = –0.0113; rBi(Mn) = –0.0004; rBi(Ni) = –0.0013; rBi(Mn) = 0.0002 and rPb(Si) = –0.0002; rPb(Mn) = –0.0015; rPb(Ni) = –0.0021; rPb(Cr) = 0.0003.

Dependences of logarithm activity coefficients of bismuth and lead from silicon, manganese, chromium and nickel contents in iron-base alloys were obtained. A comparative analysis of lead and bismuth solubility in iron-nickel alloy at 1550, 1600 и 1650 °С was presented.