铁素体析出量对铸坯热塑性的影响

Influence of Ferrite Precipitate on Hot Ductility of Continuous Casting Slabs

连铸过程中的奥氏体向铁素体转变对铸坯的第三脆性区有重要影响,其中铁素体析出量是最主要的影响因素。在建立的奥氏体向铁素体转变模型的基础上,结合实验测定的热塑性曲线,研究了J55微合金钢连铸过程铁素体转变量对热塑性的定量影响,并将20%的铁素体析出量确定为获得较好的铸坯塑性而不导致裂纹开裂的临界铁素体析出量。在此基础上,进一步建立了铁素体析出量对铸坯热塑性即铸坯表面横裂纹敏感性的预测模型,可为连铸表面横裂纹的预防提供有效指导。

Transformation from austenite to ferrite has tremendous influence on the third brittle zone of steel in continuous casting slabs,among which,the ferrite volume fraction is the main factor. The influence of ferrite volume fraction（ FVF） on hot ductility of as-cast slabs is studied for steel grade J55 microalloy steel with the established ferrite transformation model and hot ductility curves. Meanwhile,20% is settled as the critical FVF in order to obtain a better hot ductility in the unbending processes. Then the surface cracking sensitivity prediction model is built based on the relationship between hot ductility and FVF,which can provide guidance for the surface transverse cracking elimination during the process of continuous casting.