Abstract: By analysis on the breakage of the high-carbon steel stranded wire SWRH82B wire pen tip, it is obtained that there is a serious carbon segregation, the center net carbide rating of pen tip fracture ≥4;and the difference in the structural transformation leads to the uneven deformation in drawing to form breaking defects. By studying the mechanism of carbon segregation in the center of 180 mm x 180 mm high carbon steel SWRH82B billet, adjusting the superheat of molten steel from 15 -40 ℃ to 20 ~30℃, decreasing casting speed from 1. 5 m/min to 1. 4 m/min, the electromagnetic stirring at the end increasing from 350 A to 400 A, the carbon segregation index of the billet decreases from 1.18 to 1.06, which significantly reduces the occurrence of SWRH82B wire pen tip fracture rate.