Abstract: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 microscope and energy spectrum analysis. The results show that the powder blocking the liquid inlet hole of the graphite crystallizer is mainly composed of SiO2, which mainly comes from the lining refractory. With the increase of oxygen content in copper liquid, Cu2O and CuO in copper melt form low melting point mixture with SiO2 in furnace lining respectively, and then precipitate with the graphite crystallizer cooling. The low melting point mixture has a lower density and adheres to the inner wall of the crystallizer. With the accumulation of the low melting point mixture, the inlet hole is eventually blocked completely. According to the failure mechanism of the graphite 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 electrolytic copper, charcoal and flake graphite, strengthening the seal in the furnace, reducing the holding time of the copper liquid, and reducing the oxygen content in the copper liquid.