The Failure Analysis And Improvement Of The Mill Balls And The Research Of The Method Of Raising The Milling Efficiency

This article utilizes the theory of abrasion and fatigue abrasion, combining the law of the mill's and mill balls' movement, to analyze ball's failure, find out the forms and mechanism of ball' failure and other factors influencing milling efficiency .Then according to microstructure demand , property demand , economic demand and feasible demand of industrial production of organization for the ball, we calculate the ball's hardness and impact toughness suit to the demand of the coal mill in the thermal power plant of Yumen petroleum administration bureau. By comparison of several domestic commonly used ball material, combining the factory's actual conditions ,a excellent sort of material ball is elected - high chromium cast iron ball.Through the analysis of high chromium casting iron's chemical composition, the reasonable percents of various element of the bal are designed, and we have recommended a kind of high chromium casting iron ball - Crl5 ball and the process of melting and heat treatment which suit to the ball.Through the abrasive experiments of 45Mn ball , low chromium casting iron ball and high chromium casting iron ball, the wear-resisting performance of these three material balls is contrasted. We prove that high chromium casting iron ball's relatively good wear-resisting performance further by way of experiment.This text has researched other several remarkable factors influencing milling efficiency of the ball mill: rotational speed , diameter and back filling rate of the balls, ball-size distribution ,the ball-load added proportion and the method of adding balls. Based on the analysis of these factors, the best parameters of them are obtained and the technological course of balls abrasion is emulated by computer.This text, to research and improve several kinds of main factors of influencing the milling efficiency, has offered the effectual method for the coal mill's productivity, can create the direct and indirect social benefits in many aspects and economic benefits for thermal power plant.