| Liners in the heavy duty semi-autogenous mill which are applied in metallurgical mine, experience extremely working conditions (strong impact, abrasive wear and corrosive abrasion), the traditional manganese steel is hard to meet the requirements of actual production. Whereas, the super-high manganese steel has excellent anti-wear performance under high stress and strong impact working conditions, which can meet the requirements of large wear resisting components. However, as is well-known, if the processing way can’t be controlled very well, many problems will appear in the actual use. Therefore, vast manufacturing enterprises dare to use it. This paper is based on the Super-high manganese steel liner (ZGMn17Cr2) for heavy duty semi-autogenous mill ((?)5.5m) produced by a foundry manufacturer for a dressing plant in Saudi Arabia. Considering those problems (fasting bolt break off, serious deformation, crack and easy fracture) appeared in the process of service, this paper focuses on four aspects (the structure of the liner, the composition of super-high manganese steel, casting technique and heat treatment process). Through analyzing combined with the experimental data and theory, we have solved many problems for the enterprise, significantly extending the service life of the liner and solving above mentioned problems. The main results as follows:(1) Based on the analysis of the original liner structure without changing the structure after liner is installed in the semi-autogenous mill and affecting the normal work efficiency of the mill, we improve the structure of the liner significantly such as the structure strength of the liner is higher in order to resist buckling deformation in certain degrees. On the other hand, the improvement of the structure can avoid the interaction between the fasting bolts effectively which is caused by deformation. Thicker liner increase the amount of wear and extends the service life.(2) On the basis of the material ZGMn17Cr2, we explored the effects of the alloying elements (Mo, V) addition and the rare earth modification on the structures and properties of the super-high manganese steel. Researches show that the amount and shape of the carbide in steel increases through the Mo and V addition and the rare earth modification, and the structure distribution tends to be more uniform.(3) According to the improved structure and composition, we redesigned and simulated the casting process by using ProCAST, and the casting process parameters were optimized according to the simulation results. The results have great important guiding significance for the actual production, effectively shortening the production cycle and reducing the cost of production.(4) Based on the designation of ZGMn17Cr2MoV components in this paper, the effects of water toughening treatment and precipitation strengthening heat treatment on mechanical properties and the law were studied. The results show that, on the basis of compositions modification, appropriate water toughening treatment can eliminate the carbides continuous distribution at grain boundaries and control the quantity and shape of carbides, which is the fundamental precondition for the super-high manganese steel to obtain high toughness and prevent fracture. Moreover, optimized precipitation strengthening treatment can further significantly improve the impact toughness, tensile strength, yield strength and original matrix hardness.In this study, combining with the microstructure evolution, the mechanism of aboved process on the properties and the actual meaning of the properties improvement for service were discussed. |
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