高强度二冷对高碳钢小方坯凝固组织和中心碳偏析的影响

Effect of High Secondary Cooling Intensity on Solidification Structure and Center Carbon Segregation of High Carbon Steel Billet

试验了250A/5Hz电磁搅拌连铸150 mm×150 mm方坯时二冷比水量对0．64％-0．82％C钢铸坯冷却速度、凝固组织和中心碳偏析的影响。结果表明,当二冷比水量由0．83 L/kg增加至1．55 L/kg时,距铸坯边缘46 mm处的一次枝晶臂间距由380μm降至300μm,平均中心碳偏析指数由1．15降至1．10,同时等轴晶比例由45％降至40％,二次强冷工艺适合于小方坯连铸。

The effect of water ratio in secondary cooling zone on billet ccoling speed, solidification structure and eenter carbon segregation index of 0.64% - 0.82%C steel 150 mm × 150 mm billet casting with 250A/5Hz electromagnetic stirring has been tested. The results showed that with water ratio in secondary cooling zone increased to 1.55 L/kg from 0.83 L/kg, the primary dendritic ann spacing at the location with distance from billet edge 46 mm decreased to 300 μm from 380 μm, the average center carbon segregation index decreased to 1.10 from 1.15 and at the some time the ratio of equiaxial crystal decreased to 40% from 45%. The high secondary cooling intensity is only fit for billts casting.