Analysis of the Types and Distribution of Inclusions in H13 Die Steel Electroslag Ingots

The H13 die steel was prepared by 2 t electroslag remelting furnace. Combined with thermodynamic calculation， experimental observation and statistical analysis， the type， size， morphology and distribution of inclusions in H13 die steel in electroslag ingot under a melting rate of 0.12 kg/s were systematically studied. The results show that the main inclusions in H13 die steel are MgO·Al2O3 and spherical CaO·MgO·Al2O3. During the remelting process of electric slag， MgO·Al2O3 inclusion evolves into MgO·Al2O3+CaO·Al2O3 mixed type inclusion or class CaO·MgO·Al2O3 inclusion. At the same time， a small amount of S will be precipitated with various inclusions as nucleation particles. The precipitated component is mainly CaS， forming CaO·MgO·Al2O3 inclusions wrapped by CaS. The size of inclusions in the electroslag ingot is mainly less than 5 μm， 5-10 μm inclusions are less， and only a small amount of inclusions larger than 10 μm exist. The distribution is similar to that of the electrode， but the overall number of inclusions is reduced. The radial distribution shows a trend of increasing first and then decreasing， and the enrichment of inclusions occurs near half of the radius.