脉冲电流对稀土钢液侵蚀耐材的影响

Study on the effect of pulsed current on the erosion of refractory material by rare earth steel liquid

  • 摘要: 浸入式水口作为连接中间包和结晶器的重要功能性耐火材料,其安全稳定的运行对 连铸过程具有重要意义。然而,随着稀土在钢中的高质化应用推广,研究发现浇注稀土钢时极易造成浸入式水口的结瘤和堵塞。本文以Al2O3-C质耐火材料为实验对象,研究脉冲电流对稀土钢液侵蚀耐材的影响,探讨其对耐材侵蚀层界面反应的作用机理。结果表明:正常侵蚀处理的耐材表面结构因脱碳反应被严重侵蚀、破坏,导致界面粗糙多孔、不平整;而在脉冲电流作用下,耐材表面结构更加平整光滑且致密,颗粒保存完整,没有明显的夹杂物吸附,主要是表面的Al2O3、SiO2和RE2O3会发生反应生成初始产物Ce4Si5Al5O23.5,以此来延缓石墨的脱碳速率,抑制钢液对耐材的侵蚀,其中浸泡30 min时,侵蚀层平均厚度降低最多达67.6%。

     

    Abstract: As an important functional refractory material connecting the intermediate ladle and the crystallizer, the safe and stable operation of the submerged entry nozzle is of great significance to the continuous casting process. However, with the promotion of high-quality application of rare earth in steel, it is found that the casting of rare earth steel very easily causes caking and clogging of submerged entry nozzles. In this paper, with Al2O3-C quality refractory material as the experimental object, the effect of pulsed current on the rare earth steel erosion refractory material was studied, and the mechanism of its action on the interfacial reaction of the refractory material erosion layer was explored. The results show that the surface structure of regular erosion-treated refractory material is severely eroded and damaged due to a decarburization reaction, resulting in a rough and porous interface and unevenness. While under the action of pulsed current, the surface structure of refractory material is more flat, smooth and dense, with the preservation of particles intact and no apparent inclusions adsorbed, mainly because the surface of Al2O3, SiO2 and RE2O3 will react to generate the initial product Ce4Si5Al5O23.5 to retard the decarburization rate of graphite and inhibit the erosion of steel on the refractory material, in which the average thickness of the erosion layer is reduced the most when immersed for 30 min, up to 67.6%.

     

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