Removal of Fine SiO<sub>2</sub> Composite Inclusions from 304 Stainless Steel Using Super-gravity

The super-gravity technique was used to remove the SiO2 composite inclusions from 304 stainless steel. The effects of different super-gravity coefficients and super-gravity treatment time on the removal effect of inclusions were studied. It was found that the SiO2-based composite inclusions floated up to the top of the sample after the super-gravity treatment, and the inclusions in the lower part of the sample were largely removed. The volume fraction and number density of inclusions presented a gradient distribution along the direction of the super-gravity, which became steeper with increasing gravity coefficient and treatment time. The total oxygen content at the bottom of the sample was reduced from 150 ppm to 93 ppm within 15 min of super-gravity treatment under the gravity coefficient of G = 80.