南钢板坯三角区裂纹形成因素分析及控制

在对南钢板坯铸机二冷喷嘴测试和二冷制度计算机仿真的基础上,通过低倍和硫印分析铸坯三角区裂纹类型和形成原因,从结晶器锥度、喷嘴选型、布置方式和配水等方面提出解决措施。生产应用表明,板坯三角区裂纹发生率大幅下降,20g和16MnR钢种改判率从2 71%降低到1 40%;轧后每月探伤量增幅50%,探伤合格率从91 86%增加到93 20%。

Analysis and Control of Factors of Triangular Area Cracking of Continuously Cast Slab at Nanjing Steel

For the slabs cast at Nanjing Iron and Steel Group Co., the type and formation of cracking in triangular area were analyzed based on nozzle characteristic measurement and secondary cooling simulation by several methods, such as macroscopic structure study and sulfur print test. The measures to product cracking in triangular area were put forward including mold taper control, improvement in nozzle type, nozzle arrangement and secondary cooling schedule. After adopting the improvement measures, the rate of slab with triangular cracking has been obviously descended. The amendment rate of the slab for ship, 20g and 16MnR steel was decreased from 2 71% to 1 40%. The ultrasonic test amount per month for rolled steel plate was increased by 50%. The acceptability rate of ultrasonic test for rolled steel plate was increased from 91 86% to 93 20%.