The macrosegregation law  of  C

S

P  and  Al  in  240  mm×240  mm  cast  billet  of  steel  40Cr(0.38  ~ 0.40C

0.90~0.91Cr

0.015～0.029P

0.009~0.014S)has    been    studied    by  the    technology    of   original    position statistic  distribution  analysis(OPA).The  study  indicated  that  with  45%～63%  equiaxial  crystal  rate  in  billet

there  has not  any  effect  of overheating temperature(5~32  ℃)of molten  steel  in tundish  on macrosegregation  of C

but there has  an obvious effect on macrosegregation of S and P. The S presents center positive segregation

P presents center negative segregation

and  low  overheating  temperature(5℃)could  not  decreases  S  and  P  segregation.Al

2

O

3

inclusions  concentrated  at center of cast billet leads to Al element center positive segregation.