The effects of molybdenum and chromium on the malleablization of white cast iron

Abstract

<p>A study has been made of the quantitative effect of molybdenum upon the decomposition of iron carbide in the malleabilization process for white cast iron. Molybdenum contents from one to five percent were employed;It has been shown that the rates of graphitization for both secondary and primary stages definitely decrease with an increase of the molybdenum content. The secondary stage is practically negligible for the five percent molybdenum alloy over a time interval of 255 hours;Definite time requirements for the primary and secondary stages of graphitization have been determined for each molybdenum composition. These results are shown in tables in their proper sequence;It has been shown that the presence of molybdenum results in a positive refinement of the grain structure;No attempt has been made to correlate the physical properties of the alloys with the chemical composition except the observations that were made during the breaking, grinding and polishing of the samples. Such observations have led to the belief that molybdenum imparts increased hardness, toughness and tensile strength to the malleabilized iron;The effect of chromium, alone and in combination with molybdenum, upon the rates for the decomposition of iron carbide in white cast iron has been determined. It has been found that the graphitization is completely stopped in all alloys containing chromium from one to five percent;Photographs have been included to show the effects of molybdenum, chromium and molybdenum-chromium combinations;The general free energy equation has been applied in the theoretical prediction of the effects of selected elements on the rates of graphitization of commercial white cast iron. Experimental evidence offers confirmation to these theoretical predictions;A general review of the literature, as applied to the effects of various elements on graphitization rates, has been given. A comprehensive bibliography is appended.</p>