为减少连铸板坯角部横裂纹，在分析连铸坯角部横裂纹形成机制的基础上，提出了通过倒角结晶器减少角部横裂纹，以改变连铸板坯角部的二维传热，提高矫直时连铸坯的角部温度。数值模拟计算的结果表明，相对于直角连铸坯，倒角连铸坯在矫直区连铸坯角部温度明显提高，消除了角部Z向应力和应变集中。工业生产数据表明，采用倒角结晶器后，矫直区连铸坯角部温度从810~855℃提高到901~932℃，有效避开了钢的高温脆性区，连铸坯角部横裂纹发生率从10.6%稳定控制到1.6%以下，显著减少了连铸坯角部横裂纹。目前倒角结晶器稳定应用于首秦，所生产钢种涵盖了普碳钢、低合金钢、低碳钢和中碳含铌钢等。
In order to eliminate the transverse corner cracks in slabs, formation mechanism of transverse corner cracks was analyzed in Shouqin. On the basis of the analysis, a design of one kind of mould with chamfered corners was proposed to modify the 2D heat transfer conditions at slab corners and so to elevate slab corner temperature in unbending zone. The numerical simulation results show that temperature at chamfered slab corners increased remarkably and the concentration zone of Z direction tensile stress and equivalent strain at chamfered corners were eliminated compared with square corner slabs. Industrial production data show that in comparison with square corner slabs, temperature at chamfered corner slabs increases form 810-855℃ to 901-932℃ in the unbending zone, which is higher than the temperature of low ductility trough. Therefore, the transverse corner cracks were improved and cracks rate decreases from 10.6% to 1.6%, which shows a very significant effect to remove slab transverse corner cracks. Now the moulds with chamfered corners have been applied as a regular measure in Shouqin to eliminate transverse corner cracks in slabs of all steel grades.
参考文献
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