SWRH72BCr钢连铸坯表面常常发现有异常振痕的部位表层有网状渗碳体.研究了网状渗碳体的形成原因.结果表明:保护渣液渣层偏薄且厚度不均匀、结晶器振动装置偏振量大是连铸坯表层形成异常振痕的主要原因.通过优化保护渣成分,将保护渣加渣间隔时间从30s调整为23 s,结晶器偏振量从0.25 mm减小到0.10 mm,表面有异常振痕的SWRH72BCr钢连铸坯的百分率从 7.24%降低到了0.15%,表层有网状渗碳体的连铸坯百分率从 1.31%降低到了0.10%.
The continuously cast SWRH72BCr steel billets presented frequently network cementites in the surface layer of area exhibiting abnormal oscillation marks on their surface.The cause for formation of the network cementites was investigated.The results indicated that the thinner and uneven thickness of the liquid slag layer of mold powder and the large polarization degree of the mold oscillation device were responsible for the formation of abnormal oscillation marks.After some precautions,such as the optimization of mold powder composition,the adjustment of interval between additions of mold powder from 30 to 23 s,and the decrease in polarization degree of the mold oscillation device from 0.25 to 0.10 mm,were taken,percentage of the continuously cast SWRH72BCr steel billets exhibiting abnormal oscillation marks on their surface was reduced from 7.24%to 0.15%,and percentage of the continuously cast billets with network cementite in their surface layer was reduced from 1.31%to 0.10%.