高品质车轮钢二冷区冷却方式

Cooling methods in the secondary cooling zone of high quality wheel steel

为了探索高品质低成本车轮钢生产工艺,比较了两种二冷区冷却方式(气雾冷却和全水冷却)对车轮钢铸坯表面温度、凝固组织与宏观偏析的影响.结果表明:两种冷却方式下的二冷区矫直段铸坯表面温度均高于950℃,处于高温塑性区,可避免产生矫直裂纹;两种冷却方式均得到了均匀对称的凝固组织;虽然气雾冷却可略微增加等轴晶比例和降低铸坯中心偏析,但是使铸坯枝晶间距变得较为粗大,并且加重了1/2半径附近处的偏析,对随后的加工和成品的质量更为不利.综合考虑实验结果和生产成本,认为全水冷却方式更适合高品质车轮钢的生产.

The effects of mist cooling and water cooling in the secondary cooling zone on the surface temperature, solidification strLlcture and macro-segregation of wheel steel casting billets were studied to explore the high-quality low-cost production technology of wheel steel. The results show that the surface temperature of the casting billets in the straightening segment is above 950 ~C by both the cooling methods, which belongs to a high temperature plasticity zone and can avoid straightening cracks. A symmetrical solidification structure is obtained by both the cooling methods. Although mist cooling can slightly increase the proportion of equiaxed grains and decrease the central segregation of the casting billets, the dendrite arm spacing and the segregation degree around the half-radius region increase, which are even more unfavorable to the subsequent process and the quality of the finished product. Considering experimental results and production costs, water cooling should be more suitable for the production of high quality wheel steel.