Abstract: The surface depressions and longitudinal cracks of 2Cr13， 3Cr13， and 4Cr13 casting billets produced through 4-machine and 4-strand continuous casting machines in a special steel plant were analyzed and studied， the surface depression and longitudinal cracks of Cr13 stainless steel billet were solved by processing measures. Pre-melting mold flux consisting of 28%-31% SiO₂ ， 28%-31% CaO ， 6%-9% Al₂O₃ ， 7%-10% Na₂O and 3%-6% F^- were used， and comprehensive carbon preparation， especially the addition of carbon black was increased； the total carbon content was 15%-18%. The basicity of mold flux was controlled at about 1.0， the melting temperature was 1130-1150 ℃， and the viscosity at 1300 ℃ was 0.40-0.55 Pa·s. The turning temperature of the mold flux was 1140-1180 ℃， and the crystallization rate was about 48.8%. The superheat of 2Cr13 liquid steel in the tundish should be less than 30 ℃， and the superheat of 3Cr13 and 4Cr13 liquid steel should be less than 35 ℃. Automatic slagging is adopted in continuous casting process to control appropriate slag layer thickness and keep liquid level stable.

Key words: Cr13 Martensitic Stainless Steel, Continuous Casting, Longitudinal Cracking, Mold Flux

摘要： 针对特钢厂4机4流连铸机生产的2Cr13、3Cr13、4Cr13铸坯表面凹陷、纵裂缺陷进行分析和研究，通过工艺措施解决了Cr13型马氏体不锈钢铸坯的表面凹陷和纵裂问题。采用预熔型保护渣，其中SiO₂和CaO均为28%~31%、Al₂O₃为6%~9%、Na₂O为7%~10%、F^-为3%~6%，以及综合配碳，尤其是增加炭黑的加入量，总C含量为15%~18%。保护渣碱度控制在1.0左右，熔化温度为1130~1150 ℃，1300 ℃时黏度为0.40~0.55 Pa·s；保护渣转折温度为1140~1180 ℃，结晶率约为48.8% 。控制中间包内2Cr13钢液过热度≤30 ℃，3Cr13和4Cr13钢液过热度≤35 ℃；连铸过程中采用自动加渣方式，控制适宜的渣层厚度并保持液面稳定。

关键词: Cr13型马氏体不锈钢, 连铸, 纵裂, 保护渣