Abstract: The effect of single roll soft reduction (6~20mm) and reduction position (1^#〜6^#roll) on central carbon segregation and macrostructure of 180mmx180mm casting billet of high carbon steel SWRH92B (/%: 0.71C, 0.22Si, 0.64Mn, 0.010P, 0.006S) has been tested and studied. Results show that as solid fraction fs is 0.45~0.63 the soft reduction is available to decrease central carbon segregation of casting billet, and as the solid fraction fs is more than 0.82 the shrinkage cavity of billet can not be eliminated and the central carbon segregation can not be decreased； in condition of soft reduction 6~20mm, with increasing reduction the central carbon segregation decreases from 1.15 to 1.04, and the cracks occur easily in billet as the soft reduction is more than 15mm；compared with weak secondary cooling ( water ratio 0.65L/kg) and the ultra weak secondary cooling ( water ratio 0.40L/kg) is more favorable to control central carbon segregation；by comprehensive analysis it is obtained that with casting speed 1.3 m/min, mold stirring 300A and 5Hz, and secondary cooling water ratio 0.40 L/kg, the central carbon segregation and macrostructure of steel SWRH72B 180mmx180mm casting billet are better by single roll soft reduction 15mm at 5^#roll.

摘要： 试验研究了单辊轻压下量（6~20mm）和压下位置（1^#~6^#辊）对高碳钢SWRH72B（/%:0.71C,0.22Si,0.64Mn,0.010P,0.006S）180mm×180mm铸坯中心碳偏析和低倍组织的影响。结果表明,在固相率fs为0.45~0.63时,施加单辊轻压下有利于降低连铸坯的中心碳偏析,当固相率fs大于0.82时,无法消除缩孔和降低中心碳偏析;在压下量620mm,随着压下量的增加中心碳偏析度从1.15降低至1.04,在压下量大于15mm后铸坏容易出现裂纹;超弱冷（比水量0.40L/kg）较弱冷（比水量0.65L/kg）更有利于控制中心碳偏析;综合分析得出,SWRH72B钢180mm×180mm铸坯在拉速1.3m/min,结晶器搅拌300A、5Hz,比水量0.40L/kg时,5^#辊单辊轻压下的压下量15mm铸坯中心碳偏析和低倍组织最佳。

关键词: 高碳钢SWRH72B, 180mmx180mm铸坯, 碳偏析, 单辗轻压下, 低倍组织