On the Liquidus Line of Fe-Mn Alloys

The equilibrium diagram of iron and manganese alloys containing more than 50 per cent of manganese was studied by means of the thermal analysis. The melting point of pure manganese slowly fell with the addition of a small quantity of iron, and the minimum was found at the point of 91 per cent manganese, the temperature being 1240℃. The γ-δ transformation point of pure manganese rapidly rose with the iron content, and realized the peritectic reaction, liquid +δ manganese solid solution ⇄ γ manganese rolid rolution. The β-γ transformation point gradually rose with the iron content, and reached the maximum of 1130℃ with 91 per cent of manganese, and then slowly fell with the further increase of iron to the eutectoid point of 1025℃ with 71 per cent manganese, where the reaction, γ manganese solid solution ⇄ γ iron solid solution +β manganese solid solution, occurred

Some Studies of Nodular Graphite Cast Iron

The experiments were carried out on the formation of nodular graphite in cast iron by adding some different kinds of mother alloys to molten cast iron and on the increase of graphite particles caused by annealing treatment. The yield of modified element in cast iron is increased as the content of alloying element in mother alloy or the amount of mother alloy added to molten cast iron decreases. By using many components alloy the structure in which the ground mass consisted fully of ferrite, is obtained. The hardness of modified cast iron decreases rapidly by annealing or with the increase of the diameter of specimen

On the Equilibrium Diagram of Ternary Alloy System of Iron, Manganese and Carbon

The diagram of the ternary alloy system of iron, manganese and carbon was determined by thermal analysis, thermal dilatation, magnetic analysis, microscopic examination and X-ray analysis, with・alloying materials of electrolytic iron, distilled manganese and sugar charcoal. As for primary crystal surfaces, there were the following seven kinds of primary crystal surfaces : (1) δ iron ternary solid solution : ternary solid solution of δ iron in which a small amount of manganese and carbon are dissolved, (2) γ iron ternary solid solution : ternary solid solution of γ iron in which manganese and carbon are dissolved, (3) C ternary solid solution : ternary solid solution of carbide (Fe, Mn)_3C consisting of Fe_3C which contains manganese, (4) δ manganese ternary solid solution : ternary solid solution of δ manganese in which a small amount of iron and carbon are dissolved, (5) γ manganese ternary solid solution : ternary solid solution of γ manganese in which iron and carbon are dissolved, (6) βC ternary solid solution, in which iron is dissolved in βC solid solution of manganese and carbon binary alloy, (7) αC ternary solid solution, in which iron is dissolved in αC binary solid solution of manganese and carbon. Intersecting one another, these surfaces gave six kinds of peritectic lines, four kinds of eutectic lines, two peritecto-eutectic points and one ternary eutectic point. In the solid state, three kinds of peritecto-eutectoid reactions and four kinds of eutectoid reactions were observed. Moreover, fifteen eutectoid lines, three peritectoid lines, three peritecto-eutectoid points, four ternary eutectoid points and forty six solubility surfaces were confirmed. The cause of the weathering of iron alloys of high manganese and high carbon was plainly understood from the complete diagram of the system. In other words, it was shown that the weathering could be attributed to the disintegration of αC solid solution or of γC solid solution or of both owing to the moisture in atmosphere, and accordingly some appropriate means to prevent the alloy from being weathered could be devised

On the Equilibrium Diagram of Manganese and Carbon Alloy

The equilibrium diagram of manganese and carbon system was studied with distilled manganese and sugar charcoal. In this alloy scries, seven kinds of solid solutions, α, β, γ, δ-manganese solid solutions, αC, βC and γC solid solutions, existed and their existing regions were clarified, On solidification, three kinds of peritectic reactions occurred at 1235°, 1260° and 1340℃, respectively, and in the solid state, two kinds of peritectoid reactions existed at 857℃ and 1010℃, respectively, and two kinds of eutectoid reactions at 820℃ and 950℃, respectively. α-Manganese dissolved about 0.3 per cent of carbon at room temperature, and 1.0 per cent of carbon at eutectoid temperature 820℃. Maximum solubility of carbon in β-manganese was 0.05 per cent at 857℃. γ-manganese dissolved a comparatively large amount of carbon, say, 2.95 per cent of carbon at 1260℃. Solubility of carbon in δ-manganese at 1235℃ was 0.12 per cent. αC solid solution was a new phase recognized first by the present writer. It contained more than 7.0 per cent of carbon, and was conceived to be manganese carbide Mn_2C (9.85%C) with dissolved manganese. Manganese carbide Mn_3C which had been supposed to exist, was not recognized \u27in the present reseach. βC solid solution was observed in the alloys containing more than 3.05 per cent of carbon at high temperatures. Quenched βC solid solution was comparatively stable at room temperature and the so-called weathering phenomenon scarcely occurred under this condition. The γC solid solution produced by the peritectoid reaction at 1010℃ was also found newly by the present writer, the composition of which seemed to be about Mn_4C (5.18%C). This phase existed at room temperature in the range from 4.3 to 4.6 per cent of carbon

On the Magnetometric Studies of Transformation in Pure Manganese

The transformation points in pure distilled manganese were magnetometrically investigated by the modified Weiss\u27s method. It was found that the manganese had four phases, α, β, γ and δ, in solid state and that the three transformation points were 702, 1065 and 1138℃, respectively. The melting point of the pure manganese was 1252℃. The behaviours of these transformations were also clarified