Effect of Ca and S on inclusion removal during vacuum degassing refining process
The effect of Ca and S on inclusion removal during vacuum degassing refining process was investigated.The Ca content had a significant effect on inclusion removal.When the S mass fraction was in the range of 0.012％-0.014％,low Ca content was beneficial for inclusion removal.When the Ca mass fraction was 1 × 10-6 in steel,the inclusion removal rate was 74.30％.When the Ca mass fraction was 8 × 10-6 in steel,however,the inclusion removal rate decreased drastically to 33.95％.The reason was that the Ca element transferred the solid deoxidation product Al2O3-MgO inclusions to liquid calcium aluminate inclusions which were not easy to float and remove.When the Ca mass fraction was(7-8)× 10-6 in steel,high S content was beneficial for inclusion removal.When the S mass fraction was 135 × 10-6 and 11 ×10-6 in steel,the corresponding inclusion removal ratios were 33.95％and 23.71％,respectively.The reason was that high S content increased the CaS content in the inclusions,which made the melting point of inclusions increased.The sources of Ca and S elements were discussed,and measures were proposed to improve the inclusion removal ratio during vacuum degassing refining process.
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维普
