The Research on the Effect of Cooling Rate on Isothermal Crystallization Kinetic of C2S in Gas Quenching Steel Slag

摘要

Gas quenching steel slag was heated some time at different temperatures,and was cooled down by different cooling rate.The law of the effect of cooling rate on crystallization and growth of C2S in gas quenching slag was analyzed by metallographic microscope and metallographic analysis software.Microscopic morphology and element presence speciation of slag was studied by scanning electron microscopy and spectrum analyzer.The law of the effect of cooling rate on isothermal crystallization kinetic of C2S was studied by JMAK equation.The results showed that cooling rate affected the isothermal crystallization of C2S.When the cooling rate was low,it was conducive to crystal growth,and would form a complete coarsening of crystal.When the cooling rate was high,it was conducive to nucleation,but it was not conducive to crystal growth.When the slag was heated at 1450°C for 30 min and cooled down by air and Liquid nitrogen respectively,the mean diameter of C2S were 34.80 μm and32.15 μm respectively,the crystallization area of C2S were60.97％ and 56.37％ respectively.In this experiment the activation energy of C2S isothermal crystallization in gas quenching steel slag cooled by air and liquid nitrogen was-31.34kJ/mol and-1.98kJ/mol respectively.Accelerate the cooling rate can reduce the crystallization activation energy.It was conducive to crystal growth.