Research On Corrosion Wear Properties Of Grinding Ball

Grinding ball,as the important grinding media of the ball mill,is susceptible to abrasive wear,impact wear and corrosion wear to cause materials loss at the service condition of the wet milling.After more than half a century of development,the grinding balls are produced by casting,forging and rolling techniques.In this study,the microstructures,mechanical properties and corrosion wear performances of six kinds of balls,including carbidic austempered ductile iron(CADI)grinding ball,sodium silicate quenching ductile cast iron grinding ball,oil quenching ductile cast iron grinding ball,high chrome grinding ball,forged steel grinding ball and the rolling ball,were systematically investigated.Simultaneously,the effect of Nb content on the corrosion wear properties of the CADI was also investigated.The static immersion,electrochemical,erosive and impact corrosion wear tests at the pH value 3,5,7,9,11 conditions were carried out.And the effect of corrosion media on the corrosion wear properties was systematically investigated.The results showed that: 1)The surface hardness of the high chromium grinding ball,forged steel grinding ball,rolling grinding ball and CADI grinding ball can reach 60 HRC.The microstructure of the CADI grinding ball contains ausferrite,graphite balls and carbides,and the improvement of the surface hardness of the CADI grinding ball is attributed to the stress induced martensite transformation.2)The amount of the retained austenite of the CADI grinding ball increases with the increase of Nb content,and the Maximum value is at the Nb content of 0.6 wt.%.The hardness of HRC increases with the increase of Nb content,however,the impact toughness decreases greatly.3)The most severe corrosion of the grinding ball materials is at the condition of acidic solution of pH=3,and the corrosion degree firstly decreases and then increases with the increase of the pH value.The forged steel and hot-rolled grinding balls have the best corrosion resistance.The best corrosion resistance of the CADI grinding ball containing niobium is at the Nb content of 0.6 wt.%.4)CADI grinding ball and high chromium grinding ball showed the smallest weight loss in the erosive corrosion wear test.In the high stress impact corrosion wear test,the CADI grinding ball shows the best corrosion wear resistance.5)The interaction of corrosion and wear is different during the two kinds of the corrosion wear tests.The weight loss of wet milling is 10~30 times of dry milling in erosive corrosion,however,in impact corrosion condition,the weight loss of wet milling is 1~2 times of dry milling.6)In the acidic slurry,the corrosion wear mechanism of the grinding ball is mainly erosion wear;in the neutral slurry,corrosion wear mechanism is mainly particle cutting and impact fatigue spalling;in the alkaline slurry,the corrosion wear mechanism is mainly particle cutting and erosion peeling.