小方坯带液芯重压下裂纹倾向试验研究与探讨  

Study on crack tendency of the heavy reduction on liquid core of billet

作　　者：钱亮 董其鹏 李泽林[3] 陈志凌 韩丽娜 

机构地区：[1]中冶连铸技术工程有限责任公司北京冶金技术研究院,北京100028 [2]北京科技大学钢铁冶金新技术国家重点实验室,北京100083 [3]鞍钢股份有限公司炼钢总厂,辽宁鞍山114021

出　　处：《炼钢》2016年第2期30-35,73,共7页Steelmaking

摘　　要：连铸压下技术是一项解决铸坯内部质量的重要技术，基于180mm×180mm断面小方坯72A钢种大量单辊重压下（5-20mm压下量）的结果，讨论了压下裂纹问题。结果表明：相比较于多辊轻压下，单辊重压下导致压下裂纹的可能性更小；就72A钢种，在铸坯中心固相率大于0．3以后的位置进行单辊重压下，铸坯实际变形在16mm以内未出现裂纹。进一步分析裂纹机理可以发现：单辊重压下的变形量更多作用到了铸坯芯部；当压下在脆性区（ZST到ZDT区间）产生裂纹后，单辊重压下的裂纹向芯部发展，而多辊轻压下的裂纹更倾向于向坯壳方向发展。Heavy reduction is a important technology that can effectively improve the internal quality of the billets. However, effective prevention of cracks was very essential during the implementation of this mechanical reduction technology. In this study, formation mechanisms of cracks in the 72A steel as-cast billets （180 mm× 180 mm） with heavy reduction of 5-20 mm by a single pair of rollers were discussed. It was found that tendency of cracks was weaker during heavy reduction compared to soft reduction. With heavy reduction by 16 mm at a solid fraction of larger than 0.3 by the single pair of rollers, no cracks were observed in the 72A steel billets. Based on the experimental result, formation mechanisms of cracks were proposed as following： compared to soft reduction, stress can be much more effectively transferred to the center of the billets. With the initiations of cracks during reduction, they tended to develop towards the center of the billets by single pair of rollers, nevertheless, the initiated cracks preferred to grow towards the shells of the billets during soft reduction by multi-pairs of rollers.

关 键 词：小方坯 重压下 轻压下 裂纹 机理 偏析 

分 类 号：TF777.3[冶金工程—钢铁冶金]