The carbon segregation at cross section of 300 mm x 340 mm casting bloom of CrMo and CrMnTi series gear steel containing 0. 20% ~ 0. 04% C produced by 100 t UHP EAF-LF (VD) -concasting flow sheet has been tested and studied. At normal production conditions
to control the casting liquid overheating extent 15 ~ 25 ℃
the secondary cooling water rate 0. 35 L/kg
and the torque of mode and final electromagnetic stirring respectively 18 and 15 cN • cm is favorable to improve the bloom segregation. The verifying results in production practice show that the extreme different of corrected carbon content in bloom is less than 0. 025% and the rating of macro segregation of rolled products is less than 2. 5.