重轨钢采用RH和VD精炼的对比研究

在其他工艺相同条件下,对钢中全氧、Al含量、H含量、夹杂物成分、炉渣等进行了对比分析。在真空时间相同的情况下,RH脱氢能力优于VD,VD脱氧能力优于RH,但VD精炼后钢中Al含量偏高,炉渣碱度偏大,夹杂物易偏离塑性区。 RH精炼后渣中MgO含量明显升高,夹杂物成分也比较分散,可能是耐火材料尤其是插入管喷补料脱落导致外来夹杂物增多,而VD精炼后渣中MgO含量变化不大,夹杂物成分相对集中。建议采用RH精炼时,应提高耐火材料质量,减少插入管喷补次数,采用VD精炼时,应适当减少石灰加入量,降低渣中碱度并延长真空处理时间。

Comparative study on refining of heavy rail steel by RH and VD

The total oxygen, the contents of H] and Al] , the inclusions and the compositions of slag by RH and VD refining treatment are compared under the other same conditions. The results show that dehydrogenation by RH is better than VD, while deoxi-dation by VD is better than RH. The final content of Al] and the basicity of slag processed by VD increase and the compositions of inclusions deviate from the plastic zone. The content of MgO in slag processed by RH increases obviously and the compositions of in-clusions are dispersed. While the content of MgO in slag processed by VD changes slightly and the compositions of inclusions are con-centrated. The differences are ascribed to refractory shedding in the snorkel of RH unit which leads to the increase of external inclu-sions. The suggestions for vacuum refining are as follows: the quality of refractory should be improved and the gunning for snorkel should be reduced with the processing by RH. While the amount of lime and the basicity of slag should be decreased, and the treat-ment time should be increased with the processing by VD.