Deoxidation of Fe-C and Fe-Si Alloys under Reduced Pressures

The effect of the porosity of alumina crucible on the deoxidation in the vacuum melting of Fe-C alloys and that of the argon pressures on the deoxidation of the Fe-C alloys were investigated. These effects were considered from the relation between concentrations of carbon and oxygen in the Fe-C alloys. The rate of deoxidation and the oxygen concentration attainable in the vacuum melting of Fe-Si alloys were examined and results were considered from kinetic and equilibrium points of view

Research on the Relation between Cast Iron and Oxygen. II : On the Mechanism of the Formation of White Cast Iron in the Presence of Carbide Forming Elements

Carbide forming elements were similar to oxygen for the formation of white (ast iron, although the amount required is greatly different from element to element. Hence, an analogous explanation was found to be applicable to the cases of carbide forming metals. This fact is collaborated by the experiments of reducing oxygen contents in cast iron melts containing carbide forming metals

Research on the High Silicon Malleable Cast Iron by the Addition of Bismuth

High silicon malleable cast iron was manufactured by adding 0.05 per cent of bismuth. The mechanical properties of this iron are better, and the periods of malleablized heat treatments are shorter than those of conventional malleable cast irons. The chilling tendency caused by the addition of bismuth begins to fade in 5 minutes after its addition to a molten iron

Research on the Relation between Cast Iron and Oxygen. I : The Mechanism of the Formation of White Cast Iron under the Influence of Oxygen

It has been known that oxygen in the melt gives rise to the tendency of forming white cast iron, but the mechanism of such a phenomenon is yet unknown. We have herein clarified this mechanism on the basis of the atomic arrangement of the melt of cast iron and the double diagram. In molten cast iron, oxygen atoms behave partly as free atoms and partly as Fe-C-O-Fe clusters, and the latter prevents the melt from solidifying at the eutectic point C\u27 (austenite-graphite) by unbalancing the lever relation of E\u27 C\u27 F\u27, with the result that the eutectic point drops from C\u27 to C of austenite-Fe_3C, inducing the formation of white cast iron. Theoretically, the oxygen, content effective for white cast iron formation was estimated to be about 0.01 per cent, an amount equivalent to the carbon percentage corresponding to E-E\u27

Experimental Research on Super-Heating of Molten Cast Iron

The experiments were performed by melting cast iron in non-oxidizing atmosphere of Tammann furnace at temperatures between 1250 and 2000℃. With the rise of melting temperature, the graphite structure of the specimens became fine and such changes are analogous to those of the structure changes due to reducing slags such as CaC_2, deoxidizing metallic elements such as Ca, Mg or vacuum melting. At low melting temperature, the structure was apt to be varied by specimens, even if their chemical compositions were equal, but at the temperature of super-heated melting, fine granular graphite structure appeared regardless of the chemical composition of specimens

Considerations on Super-Heating of Molten Cast Iron

The elimination of dissolved oxygen by carbon in cast iron melt is of importance in super-heating of cast iron. The decrease of carbon and the increase of silicon content by super-heating are not important in understanding the super-heated melting. The super-heated fine graphite structure is caused by super-cooling of melt, accompanied by deoxidation, not by solution of graphite nucleus

On the Behaviour of Graphite in Graphitic Cast Steel

Graphitic cast steels are in the hypereutectoid range and have spheroidal graphites in the as-cast state. This research can be summarized as follows : (1) Gray cast irons with the strongest graphitizing tendency have oxygen and sulfur contents in the ranges of 20～30 and 150～300ppm, respectively. It can be assumed that their contents of the graphitic cast steels are equal to those of gray cast irons having the strongest graphitizing tendency. (2) Use of carbide slag before and after melting down of raw iron materials effectively decreases oxygen contents of these steels and improves their behaviour of graphitization ; that is, the form of graphite is more spheroidal, nodules are increased and sizes become smaller than those when carbide slag is not used. (3) Concerning the fading phenomena after inoculation, there is almost no degradation in the spheroidal form of graphite, and the size of graphite becomes smaller with the lapse of time

Welding of Cast Iron and Nodular Graphite Cast Steel. I : Properties of the Heat Affected Zone of Cast Iron

Metallographic studies have been made on the structure and properties of the weld heat-affected zone in cast iron by the single-bead tests. The thickness of the ledeburitic layer varies with the melting point of the electrodes. In the martensitic layer, "white" and "dark" martensite were observed by using different electrodes and various welding conditions. It was determined from the isothermal transformation diagrams that these two types of martensite correspond respectively to fast and slow cooling below the M_s point, the critical cooling rate being about 1℃/sec. The amount of retained austenite was about 17 to 27 per cent, showing no appreciable difference between the electrodes. It was pointed out from the calculation that the diffusion of nickel from the deposited metal to the heat-affected zone was negligibly small

Studies of the Quality, Relaxation and Wear Resisting Properties of Vanadium High Grade Cast Iron

We studied Relative Harte, Reife Grad and stress released heat treatment and wear resisting property of vanadium high grade cast iron, and found that these are superior to those of plain high grade cast iron. On the stress released heat treatment at 500～600℃, for 6 hours, vanadium cast iron keeps of better mechanical properties compared to those of plain cast iron. Vanadium cast iron is more resist to abnormal abrasion causion caused by increase of friction velocity