Alumina Mining Parts Of Slurry Pump Using Cr28

Through improve compostion and structure, This paper gets new high Cr cast iron Cr28 which is appled in slurry pump, aiming at the present pituation and prospect of high Cr cast iron in Alumina ore slurry pump. A better heat treating technology of high Cr cast iron Cr28 is ensured. The parts of slurry pump which carbides plumbwith working face, is got by using the technology in directional solidification,it make resistance to corrosion-erosion heighten. Synergistic effects between erosion and corrosion in the process of material's lapse are analysed.The pefect structure of the parts of slurry pump working in the condition of hot and strong caustic alumina ore slurry is tempering martensite,and M7C3 carbides,and secondary carbides,and little retained austenite. Composition of high Cr cast iron Cr28 in the parts of slurry pump are: Cr 26-28%, C 2.4-2.6% ,Mo 0.8-1.0%, Si <1.0%, Cu 0.6-0.8%, V 0.4%, RE 0.3%.In heat treating technology ,heat treating temperature, heat preservation time and cooling rate etc make final effect in the structure after heat treating. When heat treating technology is 1000℃ ×1.5h quenching + 450℃ ×0.5h tempering,the structure of high Cr cast iron Cr28 in the parts of slurry pump is very hard tempering martensite+ scrappy dispersion M7C3 carbides + apropos secondary carbides + little retained austenite,which has better general mechanics and resistance to corrosion-erosion is 1.6 times of casting high Cr cast iron Cr28 and opposite resistance to erosion is 1.95.In the simple technology of directional solidification, average distance λ of carbides is less and rigidity R. is less when thickness of cooling iron is less. In this conditions , when average distance λ of carbides is between 16μm~17μm, resistance to corrosion-erosion of high Cr cast iron Cr28 in the parts of slurry pump is best,and opposite resistance to erosion get to 2.88 ever.In the synergistic effects between erosion and corrosion,the proportion of the wear quantity in the gross wear corrosion quantity is bigger, but the proportion of the pure corrosion quantity is small. Wear has obvious acceleration affection on corrosion ,and wear is the main reason to create corrosion. The erosion increment come from the effect from corrosion to erosion is not more than 23%,and the corrosion increment come from the effect from erosion to corrosion is not less than 99%. Enhancing in material rigidity is a bettermethod to enhance resistance to corrosion-erosion,and improving resistance to hot and strong caustic corrosion is a necessary condition.