The coil of high carbon steel SWRH82B (0. 81%C) is used for pre-stressed wire strands

and the serious net carbides in steel is important factor of wire fracture during cold drawing process. The effect of 150 mm x 150 mm casting billet stacking slow cooling time (0 ~48 h) of steel on carbon segregation in billet and carbide segregation in φ 12. 5 mm coil is tested. Results show that the deviation of carbon content in billet with direct air cooling is 0. 116%

after stacking slow cooling of billet for 12

24

36 and 48 h

the deviation carbon content in billet respectively decreases to 0. 088%

0. 080%0. 075% and 0. 076%

and the rating of net carbide in coil is also corresponding decreased ； it is available to meet the requirement for cold drawing process by stacking slow cooling for 24 h of steel SWRH82B 150 mm x 150 mm casting billet.