Inclusion distribution in ingots was studied by dissection of a 16.8 t P12 ingot and a 5.0 t H13 ingot, with the analysis of T［O］, original position statistic distribution analysis (OPA), metallographic microscope static analysis and small sample electrolysis. The results showed that the inclusions in ingots were uneven; a positive segregation area was found in the center and lower part of the ingot, while a negative segregation area was present in the central part of ingot top; inclusion segregation in a large size ingot was severer than that in a small one. A new concept, named inclusion segregation index, was put forward to quantify the segregation degree of inclusion. It was found that the segregation indexes drawn from T［O］ analysis and OPA fit well, but they were different from those obtained by metallographic microscope static analysis and small sample electrolysis in the investigation of P12 ingot, which contained a higher sulfur content; while the segregation index drawn from T［O］ analysis was close to that from metallographic microscope static analysis in the H13 ingot with a lower sulfur content.

Inclusion distribution in ingots was studied by dissection of a 16.8 t P12 ingot and a 5.0 t H13 ingot, with the analysis of T［O］, original position statistic distribution analysis (OPA), metallographic microscope static analysis and small sample electrolysis. The results showed that the inclusions in ingots were uneven; a positive segregation area was found in the center and lower part of the ingot, while a negative segregation area was present in the central part of ingot top; inclusion segregation in a large size ingot was severer than that in a small one. A new concept, named inclusion segregation index, was put forward to quantify the segregation degree of inclusion. It was found that the segregation indexes drawn from T［O］ analysis and OPA fit well, but they were different from those obtained by metallographic microscope static analysis and small sample electrolysis in the investigation of P12 ingot, which contained a higher sulfur content; while the segregation index drawn from T［O］ analysis was close to that from metallographic microscope static analysis in the H13 ingot with a lower sulfur content.