시멘트 분쇄기용 테이블 라이너의 굽힘 피로강도의 실험적 조사

An Experimental Investigation of Bending Fatigue Strength in Table Liner for Cement Mill

The vertical roller mill, which performs the grinding and partly blending of raw material, is the one of the important machine to produce ordinary portland cement. It has been reported that an unexpected fatigue failure occurred in a table liner in the course of grinding portland cement. The life of table liner is estimated to $4{\times}10^7$ cycles in the design stage, but at the field, when its operating time reaches to $2{\times}10^6{\sim}8{\times}10^6$ cycles, the fracture of table liner begins to be found. The fracture of table liner is initiated from the outside edge of grinding path contacting with the grinding roller. Its maintenance normally take 30 % of the total maintenance costs of the roller mill. Therefore, this study shows the clarification of the reasons occurring the fatal destruction of the table liner by fatigue fracture analysis utilizing fracture mechanics and by the finite element method. And, the results from Goodman diagram illustrate relationship of including information on the transition between tensile and bending fatigue strength in the fatigue characterization of table liner.