EFFECT OF CONTINUOUS COOLING RATE ON MICROSTRUCTURAL TRANSFORMATION OF 60SI2CRVAT SPRING STEEL

摘要

In this work, the phase transformational behaviors and microstructural characteristics of 60Si2CrVAT spring steel were systematically investigated as a function of applied cooling rates in the range of 0.1-10℃/s. A quenching deformation dilatometer was used to austenize and quench. The dilatometric curves between length changes and temperature of samples suggest three characteristic stages could be identified as different ranges of cooling rates, which meets well with metallographic examination and the measured hardness results. As the cooling rate increases, the structure transformed from pearlite, granular bainite to finally martensite. The F + P and B zones are completely overlapping in continuous cooling transformation (CCT) curve, which indicates that this steel is difficult to become single bainite and shows good hardenability.