Evolution of Elements Microsegregation in MnCr Alloyed Steel via Combination of Solidification and Homogenization Process

The element microsegregations of a typical MnCr‐alloyed high‐rise building steel during solidification under different solidification cooling rates (10, 500, and 1000 °C min −1 ) and subsequent homogenization treatment at a temperature of 1250 °C are investigated using a high‐temperature confocal scanning laser microscope. The results show that with the cooling rate increasing from 10 to 1000 °C min −1 , the microsegregation region becomes smaller; meanwhile, the Mn and Cr elements enriched in the finer interdendritic region are effectively eliminated after homogenization treatment due to the larger concentration gradient between the interdendrite and dendrite core. Moreover, the modified Voller–Beckermann (VB) microsegregation model is developed considering the actual partition coefficient values k under different solid fractions by the weighted interval rank sort method based on the measured electron probe microanalysis data and mass balance analysis method. The calculation results demonstrate that Mn and Cr elements in the finer interdendritic region increase with the enhancing of cooling rate at the final solidification stage, which are consistent with the results.