低碱度高结晶率连铸保护渣的研究与应用

针对攀钢连铸 Q2 35 G等包晶钢生产中出现的铸坯表面裂纹问题 ,在调查分析裂纹特征及其产生原因的基础上 ,发现保护渣传热过强和保护渣流入不均是诱发角横裂产生的主要原因。通过对保护渣结晶特性的研究 ,开发出了低碱度 (Ca O/ Si O2 <1.0 )、高结晶率的新型包晶钢用连铸保护渣。工业试验表明 ,研制的保护渣具有良好的使用效果 ,所浇铸坯表面质量优良 ,铸坯裂纹较少 ,表面角横裂发生率降低到 4 .19% ,纵裂发生率为 3.4 2 % ,且保护渣润滑作用良好 ,未发生漏钢事故。

Development and Application of Mold Flux with Low Basicity and High Crystallization Ratio

Longitudinal and transverse corner crack defects were found on the slab surface for peritectic steel grade Q235G cast in Panzhihua Iron and Steel Group Company.To solve these problems, a profound investigation was conducted on the formation causes and characteristics of such defects.The main cause of transverse corner crack is high intensity of heat conduction of mold flux.According to study on crystallizing performance of flux, a new mold flux with low basicity (CaO/SiO 2<1.0) and high crystallization ratio has been promoted for the continuous casting of peritectic steels.The results from industrial application show that the developed mold flux encourages good utilizing effects which includes a low transverse corner crack ratio of 4.19 % and low longitudinal crack ratio of 3.42 % on slab, as well as a guaranteed lubrication for moving strand and the zero record of breakouts.