310S耐热不锈钢连铸板坯表面纵裂分析和工艺改进

Analysis on Surface Longitudinal Crack of Concasting Slab of Heat Resistant Stainless Steel 310S and Process Improvement

310S奥氏体耐热不锈钢(%:0.05C、24.5Cr、19.3Ni)导热性差[100℃导热系数0.029×4.18J/(cm·℃)],200 mm×(950～2 150)mm连铸板坯易产生纵裂纹(宽0.1～10 mm,深1～20 mm)。通过采用熔点1 085℃的保护渣(ST-SP/310)替代熔点1 120℃的保护渣(ST-SP/810),结晶器宽面和窄面的冷却水流量分别从4 500 L/min和460 L/min降至4 300 L/min和430 L/min,钢水过热度从30～45℃降至20～35℃,拉速从0.95m/min降至0.80～0.90 m/min,铸坯质量明显改善,消除了表面纵裂。

Abstract As heat conductivity of austenite heat resistant stainless steel 310S （%：0. 05C, 24. 5Cr, 19. 3Ni） is poor, only 0. 029 ×4. 18 J/（cm·℃ ） at 100 ℃ , the surface longitudinal cracks with wide 0. 1 - 10 mm and depth 1 -20 mm of 200 mm ×（950 ~ 2150） mm casting slab easy produce. By using mold flux ST-SP/310 with lower melting point- 1 085 ℃ to replace mold flux ST-SP/810 with higher melting point- 1 120 ℃ , decreasing broad face and narrow face cooling water rate respectively to 4 300 L/min and 430 L/min from original 4 500 L/rain and 460 L/min, decreasing liquid super-heating extent to 20 -35 ℃ from 30 -45 ℃ and lowering casting speed to 0. 80 -0. 90 m/rain from 0. 95 m/min, the quality of cast slab obviously improves to avoid the occurrence of surface longitudinal crack.