Abstract: This paper introduces the all-carbon matrix DMT-20/T MgO-C brick for UHP electric furnace, which is made by adopting special grain size gradation and production method and increasing the amount of graphite. This brick has good resistance to oxidation, deterioration of tissue structure and erosion. It has been used in the hot area and slag line of 50 t UHP electric furnace in FS-DS steel plant, and its service life reaches 573 heats, which is 63.7% higher than that of 350 heats with the highest service life in the factory in the past, and its damage rate is 18% lower than that of our company's DMT-18A MgO-C brick. The results of microstructure study of residual brick show that the thickness of decarburized layer of all-carbon matrix DMT-20/T MgO-C brick is only 0.2～0.3 times that of traditional DMT-18A MgO-C brick, and there is no structure deterioration in the matrix between the decarburized layer and the original brick layer. This can ensure that the product has high durability and is suitable for use in UHP electric furnace.

Key words: UHP electric furnace, MgO-C brick, Durability