Extreme removal of fine inclusions from 304 stainless steel via high-temperature supergravity fields

The extreme removal of SiO₂ and MnO inclusions in 304 stainless steel in supergravity fields was investigated using an in-house high-temperature supergravity equipment. The influences of the gravity coefficient and separation time on the removal efficiency of the inclusions were studied. After supergravity treatment, the inclusions migrated to the top of the sample and formed large aggregates. Meanwhile, the lower part of the sample was purified considerably and appeared significantly cleaner than the raw material. At the gravity coefficient of 500 and separation time of 600 s, the total oxygen content at the bottom of the sample (position E) decreased from 240 to 28 ppm. This corresponded to a total oxygen removal rate of 88.33%. The volume fraction and number density of inclusions exhibited a gradient distribution along the supergravity direction, with values of 8.5% and 106 mm^–2 at the top of the sample (position A) and 0.06% and 22 mm^–2 at its bottom.