连铸大方坯角部纵向裂纹缺陷分析  

ANALYSIS OF LONGITUDINAL CRACK DEFECTS AT THE CORNERS OF CONTINUOUS CASTING BLOOMS

作　　者：蒋新华 赵骏 周志梭 Jiang Xinhua;Zhao Jun;Zhou Zhisuo(Chengdu Metallurgical Experimental Plant Co.,Ltd)

机构地区：[1]成都冶金实验厂有限公司,四川成都611300

出　　处：《河南冶金》2024年第5期15-18,43,共5页Henan Metallurgy

摘　　要：某炼钢厂生产的连铸大方坯出现批量角部纵向裂纹缺陷,影响了后续轧制材的生产。通过利用金相显微镜、扫描电镜、能谱分析仪等对缺陷样品进行观察和检测,并分析了典型缺陷的成因。典型缺陷试样的角部纵向裂纹位于角部重结晶区,裂纹附近有磷偏析产生的磷共晶组织。角部纵向裂纹的成因与连铸坯坯壳厚度不均匀以及重结晶有关,坯壳部位的磷偏析对裂纹的形成和扩展起促进作用。通过优化结晶器的倒锥度,减小连铸坯与结晶器之间的气隙,可以有效消除角部纵向裂纹;优化二冷段的冷却参数可以降低偏析。A batch of the continuous casting billets produced by a certain steel plant had corner longitudinal cracks,which affected the production of subsequent rolled materials.By using metallographic microscope,scanning electron microscope,energy spectrum analyzer and so on to observe and detect defective samples,the causes of typical defects were analyzed.The corner longitudinal crack of a typical defective specimen is located in the corner recrystallization zone,and there is a phosphorus eutectic structure generated by phosphorus segregation near the crack.The cause of corner longitudinal cracks is related to the uneven thickness of the continuous casting billet shell and recrystallization,and the phosphorus segregation in the shell area promotes the formation and propagation of cracks.By optimizing the inverted taper of the crystallizer,reducing the air gap between the continuous casting billet and the crystallizer,the corner longitudinal cracks can be effectively eliminated,and optimizing the cooling parameters of the secondary cooling section can reduce the segregation.

关 键 词：连铸大方坯 角部纵向裂纹 坯壳厚度 磷偏析 倒锥度 

分 类 号：TF777.2[冶金工程—钢铁冶金]