残余元素对连铸坯和热轧板表面质量的影响

 通过扫描电镜、透射电镜和EDS分析，对残余元素对连铸坯和热轧板表面质量的影响进行了研究。试验结果表明，连铸坯氧化层中存在铜、砷和锡同时富集。热轧板基体层与氧化层界面存在铜、砷和锡富集，基体层铜、砷和锡含量高于氧化层铜、砷和锡含量。铜、砷和锡在γ晶界偏聚和铁优先氧化造成连铸坯中铜、砷和锡富集，加热炉二次加热加剧铜、砷和锡富集，铜、砷、锡向钢基体渗透扩散，恶化钢的塑性，导致中板表面微裂纹缺陷，分析了铜、砷和锡富集相对表面微裂纹的影响机理。

Effect of Residual Elements on Continuous Cast Slab and Surface Quality of Hot Rolled Plate

The effect of residual elements on the continuous cast slabs and surface quality of hot rolled plates is studied by scanning electron microscope, transmission electron microscope and EDS analysis. The results show that some Cu, As and Sn are simultaneously enriched in the scale of slabs. Some Cu/As and Sn are simultaneously enriched in the interface of hot rolled plate scale and steel matrix, the content of Cu/As/Sn in the steel matrix is higher than that in the scale. The segregation of Cu/As and Sn at the austenite grain boundaries and Cu/As and Sn enriched phase in the slabs are formed by selective oxidation, the reheating exacerbates the enrichment of Cu/As and Sn, and the penetration and diffusion of Cu/As and Sn toward the steel matrix deteriorates the hot ductility of steel tremendously, which induce lots of surface microcracks in the hot rolled plate. The mechanism of the effect of Cu/As and Sn enriched phase on surface microcracks is analysised.