BG420CL车轮钢板坯连铸参数的优化

 针对BG420CL车轮钢是中碳、低合金、经RE处理冲压用热轧钢板，台架弯曲疲劳寿命≥600万次，依据铸机性能和生产经验及钢种性质和用途，采用试验和计算相结合，应用物理模拟，测试了板坯700～1300 ℃面缩率及最大应变，对连铸工艺的重要参数进行了优化。确定了1 m/min的拉坯速度、结晶器冷却水速在宽面是16 m/s、窄面是10 m/s；二冷比水量是0.68 L/kg弱冷却制度。并利用结晶器喂RE丝技术改形钢液中夹杂物，定义了夹杂物球化率参数。经RE处理的板坯内≤5 μm夹杂物球化率为49%，总球化率是89%；未经处理的板坯分别是2073%和5570%，RE在板坯内分布均匀，使该钢种实现了批量生产。

Optimization of Casting Parameters for BG420CL Slab

BG420CL steel is a medium carbon and low alloy steel. The BG420CL hot rolled strip has good drawability. The required fatigue life is more than 6 million times at bend test.So the quality of continuously cast slab should be improved. By combining the experimental,theoretical and practical results, the technical parameters of slab continuously casting were optimized. The reasonable parameters are:withdrawal speed is 1 m/min, speed of cooling water flow in mould is 16 m/s for wide face and 10 m/s for narrow face, the cooling water consumption is 0.68 L/kg in secondary cooling zone. In order to increase plasticity of hot rolled strip RE is wire fed into melt to modify inclusions. The rate of nodularity was defined.The RE should be distributed uniformty. The nodularity rate of inclusions which are ≤5 μm in size was 49% after RE treatment, the total nodularity rate was 89%,but for the untreated slabs, these figures were 20.73% and 55.70% respectively.The BG420CL slabs are mass produced.