Transformation of austenite on quenching high-purity iron-carbon alloys

Abstract

The tests described in this report were made primarily to show the influence of variation of distribution and solution of carbon in austenite on the mode and rate of transformation of austenite in high-purity iron-carbon alloys. The trans- formation of a nonuniform grain of austenite often proceeds at various rates in different regions within the grain, and its initial transformation to troostite is not always confined solely to its grain boundaries. These facts are illustrated by a representative case in wbich an individual grain of austenite transformed to cementite, ferrite, lamellar pearlite, nodular troostite, and martensite. The results of microhardness tests made on the decomposition products of this same grain of austenite, the influence of grain size on the transformation rate of aus- tenite, and the occurrence of cracks in quenched specimens of the hypereutectoid alloys are also discussed.