Effect of Compression Reduction on Deformation of CaO–CaS–Al2O3–MgO Inclusions in Solid and Semi‐Solid Steel

Abstract

Plain strain deformation is performed on solid steel samples at 1473 K and semi‐solid samples at 1743 K. The deformation of inclusions under the reductions of 10%, 20%, and 30% is studied. In the solid steel, the average aspect ratio of inclusions increases from 1.23 in the original slab to 2.07, 2.23, and 2.30 under the reduction of 10%, 20%, and 30%. The deformation of inclusions in the semi‐solid steel, which is much smaller than that in the solid steel, is hardly influenced by the reduction. Inclusion deformation is explained by the difference of hardness between the inclusion phase and the steel matrix. Though inclusions in steel samples deformed at 1473 K are a little harder than those in steel samples deformed at 1743 K due to the thicker CaS shell formed by the transformation of inclusion composition. Stress–strain curves indicate that the semi‐solid steel matrix at is much softer. In the semi‐solid steel at 1743 K, the soft steel matrix deforms more than inclusions, leading, in turn, to a smaller deformation of inclusions.