Abstract:The influence of the heavy reduction of the single-roller solidification end on the internal quality of continuous casting slab was discussed. The microstructure of Q345D continuous casting slab under different drawing speeds was analyzed and the quantitative measurement of the porosity of the slab center was carried out. The results showed that the internal quality of the continuous casting slab can be effectively improved by using heavy reduction. When the pulling speed was 0.70 m/min, the center porosity volume was significantly reduced at a 1/2 position and a 1/4 position of the slab width when the heavy reduction was 15 mm. The center porosity volume at the 1/2 and 1/4 position of the slab width on the condition of soft reduction was 1.73×10-7 cm3/g and 2.68×10-7 cm3/g, respectively. The center porosity volume at the 1/2 and 1/4 positions of the slab width at a heavy reduction of 15 mm was 5.33×10-8 cm3/g and -1.84×10-8 cm3/g, respectively. Under the soft reduction, the maximum value of center carbon segregation was 1.176, and under the heavy reduction of 15 mm, the maximum value of center carbon segregation was 1.282. A slight negative segregation occurred at 15 mm under a heavy reduction, and the maximum negative segregation value was 0.916.
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