PEARLITE IN ULTRAHIGH CARBON-STEELS - HEAT-TREATMENTS AND MECHANICAL-PROPERTIES

Two ultrahigh carbon steel (UHCS) alloys containing 1.5 and 1.8 wt pet carbon, respectively, were studied. These materials were processed in to fully spheroidized microstructures and were then given heat treatme nts to form pearlite. The mechanical properties of the heat-treated ma terials were evaluated by tension tests at room temperature. Use of th e hypereutectoid austenite-cementite to pearlite transformation enable d achievement of pearlitic microstructures with various interlamellar spacings. The yield strengths of the pearlitic steels are found to cor relate with a predictive relation based on interlamellar spacing and p earlite colony size. Decreasing the pearlite interlamellar spacing inc reases the yield strength and the ultimate strength and decreases the tensile ductility. It is shown that solid solution alloying strongly i nfluences the strength of pearlitic steels.