Numerical  simulation  on blooming  and rolling process  for U75V  steel heavy rail with 280 mm×380 mm cast bloom has been carried out by ANSYS/LS-DYNA software to optimize C pass of knifing pass and analyze on stress dis- tribution of cross section of blooming heavy rail before and after optimization. Results show that with pass optimization

the equivalent  stress  of heavy rail  during rolling  decreases

the  equivalent  stress  status  of middle  axle  is  improved

the  fluctuation  range  of stress  for  original  pass  is9~44  MPa  and  that  for  optimized  pass  is  8~30  MPa

and  the  middle  axle  vertical maximum stress decreases to 21.1 MPa from 41.4 MPa with original pass.