亚包晶钢连铸过程中常出现表面纵裂质量问题，与其在结晶器内较大高温相变收缩引起的初生坯壳不均匀生长密切相关，其纵裂纹敏感性可由包晶特征点计算出的包晶转变率判定。利用Factsage热力学计算软件研究钢种常见合金元素对Fe-C二元平衡相图中包晶特征点的影响，回归得到包晶特征点的预测公式。基于预测公式，可准确判断一定成分钢种的亚包晶范围，从而指导实际连铸生产中保护渣的选择。研究表明，通过合理的成分微调可有效降低包晶转变率，降低亚包晶钢高温相变收缩程度，甚至改变凝固模式变为过包晶模式，从而大大降低连铸坯纵裂纹敏感性。
Abstract
Longitudinal cracks frequently occur in continuous casting of hypo-peritectic steel which closely relates to unevenness of initial solidified shell resulting from shrinkage in mold at high temperature. The cracking susceptibility can be determined by peritectic transformation ratio calculated from peritectic characteristic points. The FactSage software was used to determine the effects of various alloying elements in steel on peritectic characteristic points in Fe-C equilibrium phase diagram and obtained the equations for calculating the peritectic characteristic points. Based on the equations, peritectic range for steel can be calculated to provide guidance for choosing the proper mold powder in continuous casting process. With proper chemical composition modification, peritectic transformation ratio can be reduced thus shrinkage during peritectic transformation under high temperature can be reduced. The solidification mode of hypo-peritectic steel can even be changed to hyper-peritectic mode which can greatly reduce the longitudinal cracking susceptibility.
关键词
亚包晶钢 /
包晶转变率 /
包晶特征点 /
纵裂纹敏感性
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Key words
hypo-peritectic steel /
peritectic transformation ratio /
peritectic characteristic points /
longitudinal cracking susceptibility
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参考文献
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