电炉连铸流程H13模具钢大圆坯的开发

Development of Round Blooms for H13 Die Steel by EAF-CC Process

H13模具钢是使用最广泛的热作模具钢,传统生产过程均采用模铸钢锭进行生产,本文采用100 t EAF-LF-VD-CC流程开发了500 mm或650 mm高洁净H13模具钢连铸圆坯。采用化学分析、氧氮分析仪分析、金相显微镜、扫描电镜等研究了大圆坯的成分、全氧含量、夹杂物及低倍质量情况等。结果表明,采用EAF-LF-VD-CC流程,采用Ca O-Al2O3-Si O2-Mg O渣系可以生产出全氧含量10 ppm以下的H13模具钢大圆坯。VD过程脱氮率可达到30%,软吹过程可以达到10%左右的脱氮率。碳偏析指数最大位置出现在铸坯内外弧1/4直径位置。铸坯洁净度及低倍质量可满足用户电渣重熔自耗电极的质量要求。

The round blooms with diameters of 500 mm or 650 mm for high clean H13 die steels were produced by 100 t EAF-LF-VD-CC process. The chemical composition and macrostructure were analyzed by oxygen and nitrogen analyzer, metallographic microscope and scanning electron microscopy（SEM）. The Results show that, by using the slag of Ca O-Al2O3-Si O2-Mg O, the H13 die steel with total oxygen content lower than 10 ppm can be produced. The denitrification rate after VD process and soft blowing process can reach about 30% and 10%respectively. The maximum carbon segregation occurs at 1 / 4 diameter of outer arc. The cleanliness and macrostructure meet the requirements of the consumbuble electrodes for electroslag remelting.