南钢小方坯连铸生产45钢二冷制度的优化

Optimization on Secondary Cooling Scheduling for 0.45C Steel Billet Casting at Nanjing Steel

通过低倍组织和二冷制度计算机仿真软件分析了2^#连铸机150mm×150mm，4^#连铸机150mm×220mm45钢铸坯中心和中间裂纹发生距弯月面的位置，铸坯表面温度与目标温度的对比。结果表明，二冷比水量和各段冷却水分配不当是形成铸坯裂纹的主要原因，通过降低二冷水量和优化冷却水分配使铸坯表面温度接近目标温度曲线，明显降低了铸坯中间和中心裂纹的发生率。

Location of medium and center crack- distance from mold meniscus and comparison between aim temperature and surface temperature of 0. 45C steel billet 150 mm × 150 mm strand of No2 caster and 150 mm× 220 mm strand of No4 caster have been analyzed by macrostructure and computer simulation software for secondary cooling scheduling. Results showed that unsuited secondary cooling water rate and cooling water distributing at each part were main cause to form billet crack, the occurrence ratio obviously decreased by decreasing secondary cooling water rate and optimizing cooling water distribution so that the surface temperature of strand was close to aim temperature curves and the oceured ratio of billet medium and center crack obviously decreased.