作者：HIROAKI OSHIMA;EIZO MAEDA;TSUNEO ISOO;
作者單位：Shinagawa Refractories Co., Ltd. 707, Imbe, Bizen-shi, Okayama 705-8577;Shinagawa Refractories Co., Ltd. 707, Imbe, Bizen-shi, Okayama 705-8577;Shinagawa Refractories Co., Ltd. 707, Imbe, Bizen-shi, Okayama 705-8577
刊名：Journal of the Technical Association of Refractories
ISSN：0285-0028
出版年：2010-01-05
卷：30
期：3
起頁：194
止頁：199
分類號：TQ175
語種：英文
關鍵詞：
內容簡介In many iron and steel works the desulfurization process for hot metal involves mechanical stirring by a high speed rotating impeller with four wings rotating at 100 to 150 rpm with burnt lime as the desulfurizing agent (KR process). The structure of the impeller is composed of a steel core surrounded by metal wire reinforced castable of the Al_2O_3-SiO_2-SiC system. The sectional area of the wire is usually less than 1 mm~2. The main cause of impeller failure is flaking that produces an imbalance and a large amount of lateral swing during high speed rotation. Interruption of the impeller action due to large amplitude swinging is a common occurrence. The application conditions differ in different steel works. However, the working conditions of the impeller castables are generally severe due to the high temperature of the hot metal that is desirable for efficiency of the desulfurization process together with the high rotating velocity of the impeller1'. To cope with these severe conditions, the castables have to have high strength and resistance against peeling-off. In many cases destructive large cracking of an impeller paddle right up to the steel core occurs in the early stage of use when no outer sign of damage in the impeller paddle is evident (Fig. 1). The early mechanical cracking damage was considered to result from an increase of elastic modulus induced by an over-sintering condition and the enhancement of thermal stress under otherwise identical working conditions.
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