TP2铜管坯水平连铸用石墨结晶器功能失效行为研究

Functional Failure Behavior of Graphite Crystallizer for Horizontal Continuous Casting of TP2 Tubular Billet

针对TP2铜管坯水平连铸用石墨结晶器进液孔堵塞导致的功能性失效问题,研究了堵塞石墨结晶器进液孔的白色粉末物质的化学成分、来源及形成机理,采用X射线衍射(XRD)、X射线荧光、差热分析、扫描电子显微镜(SEM)和能谱分析(EDS)等检测手段进行系统性分析。研究结果表明,堵塞石墨结晶器进液孔的白色粉末的组成以SiO_(2)为主,主要来源于炉衬耐火材料。随着铜液中氧含量的增加,铜熔体中的Cu_(2)O和CuO分别与炉衬中的SiO_(2)形成低熔点混合物,后经石墨结晶器冷却析出;低熔点混合物密度小,黏附在结晶器内壁,随着低熔点混合物的累积,最终导致进液孔完全堵塞。根据石墨结晶器的失效机理,对阴极电解铜、木炭和鳞片石墨等原材料及辅料采取烘干等方法,降低其携带的水分,以及加强炉内密封,减少铜液的保温时间等措施,可以降低铜液中的氧含量,减少氧化物粉末的产生,避免结晶器进液孔堵塞,从而防止结晶器功能失效。

The functional failure of the graphite crystallizer for horizontal continuous casting of TP2 tubular billet was due to that the liquid injection holes were often blocked by some white powder.The chemical composition,source and formation mechanism of these powder were systematically analyzed by X-ray diffraction,X-ray fluorescence,differential thermal analysis,scanning electron micro‐scope and energy spectrum analysis.The results show that the powder blocking the liquid inlet hole of the graphite crystallizer is main‐ly composed of SiO_(2),which mainly comes from the lining refractory.With the increase of oxygen content in copper liquid,Cu_(2)O and CuO in copper melt form low melting point mixture with SiO_(2) in furnace lining respectively,and then precipitate with the graphite crys‐tallizer cooling.The low melting point mixture has a lower density and adheres to the inner wall of the crystallizer.With the accumula‐tion of the low melting point mixture,the inlet hole is eventually blocked completely.According to the failure mechanism of the graph‐ite crystallizer,some measures were taken to prevent the function failure of the graphite crystallizer by reducing the generation of oxide powder and the possibility of blocking the mold inlet hole.The measures include reducing the moisture carried by the cathode electro‐lytic copper,charcoal and flake graphite,strengthening the seal in the furnace,reducing the holding time of the copper liquid,and re‐ducing the oxygen content in the copper liquid.