The Composition of Eutectic Conjugation in Fe-Mn-S System

Abstract

Three conjugations oj [Liquid-Iron-(Mn,Fe)S] , [Liquid-Iron-(Fe, Mn)S] and [ Iron-(Mn,Fe)S-(Fe, Mn)S] ill the Fe-Mn-S temary-!)istem cOlltaining liP to 4~o oj mallganese in iroll phase, were investigated as the first apj"oach to understand the kinetics oj sulfide jormation in steel, and the compositions oj all phases were determined in the temperature range oj 670° to 1 500°C. The results are summarized as jollows: (1) The three-phase conjugation [Liquid-Iron-(Mn, Fe)S] was observed in the temperature range oj I 004° to J 50(f'C. (2) No evidence wasjoundjor the intersection oj the eutectic line with a miscibility gap jmposed by I Ventmp. (3) The solubility q(sulfur in iron abruptfy decreased at 1 37 /°Cjrom 0. 12% to 0.(}5 % with the (j I transformation oj iron. (4) As a result qf Ihe peri tecto-eutectic reaction , jour phases oj liquid, iron, (Mn.Fe)S and (Fe, Mn)S coexisted at 1 (}04°C. (5) B elow the peritecto-eutectic temperature, both three-phase conjugatioll oj [Liquid-Iron-(Fe,M n)S] and [Iron-(Mn,Fe)S-(Fe,Mn)S] were stable. The jormer met the Fe-FeS binary at 988"C, which is the eutectic fem/J era ture.

Effect of Carbon on the Composition of Eutectic Conjugation in the Fe-Mn-S System and Equilibrium Composition of Sulfide in Solid Steel

“…Following previous work 9 ) on the Fe-Mn-S tern ary phase d iagra m, our investigation was extended to the effec t of carbon on this diagra m , esp ecially on every composition of the eutectic conjuga tio n [liquid (L )iron (F )-(Mn,Fe)S (Q )] with a close relation to th e crys tallization of sulfides. Carbon is o ne of the m ost importa nt element in steel a nd m ay h a ve a la rge effect on the sulfid e morphology.…”

State‐of‐the‐Art in the Control of Sulfides in Steels

“…Eutectic reaction (L → Fe(s) + MnS(s)) in Fe‐Mn‐S ternary system is indispensable. [ 33 ] Stable eutectic MnS (consisting of fine rod‐like MnS) was observed at the inner region and metastable monotectic MnS (relatively large granular MnS) was observed at the surface region of steel ingots containing more than 0.15% sulfur. [ 34 ] Aluminum addition aids formation of eutectic MnS, while Ca addition aids formation of monotectic MnS.…”