Continuous Cooling Transformation Behavior and Pearlite Transformation Kinetic of SLD-MAGIC Steel

The transformation behavior and pearlite transformation kinetics of SLD-MAGIC steel during continuous cooling rates were investigated. The dilatometric curves, microstructure and microhardness were studied by thermal dilatometer, OM, SEM, EDS and Vicker's hardness testing system, and CCT curve was plotted.The results show that A_c1=833℃, A_ccm=904 ℃and M_s=192 ℃.When the cooling rates is 0.01-0.30 ℃/s and 0.1-1.0 ℃/s, the pearlite and bainite phase are transformed respectively from the austenite at high temperature.When the cooling rate is more than 1 ℃/s, quenched structure is martensite and retained austenite. When the cooling rates are 0.01 ℃/s, 0.02 ℃/s, 0.07 ℃/s, the model of pearlite transformation time and volume fraction and growth mold are obtained by regression equation.The Avrami exponents n of the pearlite transformation kinetics are between 1 and 3, and the pearlite grows in one dimension and two dimension.