Study On Low Alloy Steel Wear-resisting Liner For SAG Mill

The Semi-Autogenous Grinding(SAG)mill is a kind of ore grinding equipment which is considered as environmentally-friendly and economical type.Since the SAG mill is mainly grinding ores by the ore itself,thus the cost of steel balls will be relatively low.And it shows weak chemical or electrochemical influences on the subsequent processes,such as mineral separation.Therefore,the SAG mill has been used for more and more mines industry.However,there are some problems such as short servicing life and broken of liner,which seriously restrict the efficiency and operation cost of the SAG mill.According to the application conditions of wear-resisting liner in SAG mill,the analysis on abrasion,hardness,impact toughness,metallographic microstructure and fractography were used to evaluate the alternate alloys.Both the micro-alloying and RE elements were added to improve the alternate alloys.The thermodynamic stability of design alloy was analyzed by means of the Thermo-Calc.Finally,the alternate alloys were evaluated with commissioning testing from the view point of the chemical compositions and prepare processing.Based on the testing results,it is found that the new wear-resistant steel(main components:0.38%-0.42%C,0.80%-1.20%Si,0.80%-1.2%Mn,1.80%-2.20%Cr,0.20%-0.4%Mo,0.20%-0.60%Cu,0.20%-0.25%V)shows an optimum comprehensive mechanical properties through the heat treatment process(annealing at 860℃±110℃,and then QT(quenching at 910℃±10℃ and tempering at 510℃±10℃));when the Cu content is within 0.25%-0.35%,the corrosion resistance of this steel will be best.The analysis on microstructure showed that the tempered Martensite+lower Bainite can be obtained by the above processing,which can be considered as reason why the liner has excellent comprehensive mechanical properties.In the present study,a new wear-resisting liner has been developed for the SAG mill,which combination properties are superior to that of the imported wear-resisting liners.In comparison with the imported liners,its service life increases by 15.9%,and the production cost decreases by about 700 RMB/ton.Therefore,the new wear-resisting steel not only can solve the problem that the existing wear-resisting liners for SAG mill have a short service life,but also possesses the obvious economic and social benefits.