天钢连铸板坯中心裂纹的成因分析

针对天钢炼钢厂在连铸生产中出现的中心裂纹,结合VAI动态辊缝模拟软件、铸坯凝固过程应变理论及天钢炼钢厂的生产实践,分析了产生铸坯中心裂纹的影响因素.在设备方面,辊缝超差,特别是凝固末端辊缝超差是造成中心线裂纹的主要原因.在工艺方面,铸坯在冷却过程中,由钢水成分、浇注温度以及拉速变化引起的相变降低了钢的高温塑性.在外力作用下,坯壳承受的应力之和超过了钢的允许强度和应力时,铸坯就会产生裂纹.

Causes Analysis of Slab Central Crack Formation in TISG

Aiming at central crack forming in casting production at TISG Steel-making Subsidiary,the influencing factors of slab central crack are analyzed in combination with VAI dynamic roll gap simulation software,strain theory in slab solidification process and production practice.Of equipment, roll gap off-tolerance,especially of solidification final roll,is the main cause.Of process,steel high temperature plasticity is reduced due to the transformation caused by steel composition, casting temperature and casting speed variation during slab cooling.Exerted by external force,slab shell bears overall strain exceeding allowable strength and strain,and tends to crack.