| 30CrMnSi structural steel plays a crucial role in the aerospace field due to its superior comprehensive mechanical properties.The strength and hardness of 30 CrMnSi parts are relatively high.When using the traditional surface finishing technology to finish the surface,the problems of poor quality and low efficiency often exist.As a new surface finishing technology with nanoscale processing ability,magnetic abrasive finishing has achieved good results in surface finishing of easily processed materials such as aluminum alloy,but it is difficult to achieve high-quality and efficient surface finishing for difficult materials such as highstrength alloy steel.The reason is that in the polishing process of magnetic abrasive tools,the magnetic field intensity generated by the magnetic field generating device is often less than 0.5T,resulting in insufficient grinding pressure,which cannot meet the requirements of surface polishing of highstrength alloy steel.In order to solve these problems,a series of simulation analysis and experimental research were carried out with 30 CrMnSi structural steel plate as the research object.The main research contents are as follows:(1)The latest research progress of magnetic abrasive finishing technology was reviewed,the advantages and disadvantages of magnetic abrasive finishing technology were analyzed,and the research contents of this paper were put forward: Magnetic field design and experimental study of magnetic abrasive finishing for 30 CrMnSi structural steel.(2)The influence of magnetic permeability of workpiece on the finishing of magnetic abrasive particles was analyzed.The stress state of the magnetic abrasive at the surface of the workpiece was analyzed in the finishing process of the magnetic abrasive.(3)In order to enhance the magnetic field intensity and improve the magnetic field distribution,a new magnetic field generator was designed based on Halbach Array.The overall size structure of the permanent magnet array was determined by theoretical analysis and calculation.Through the simulation analysis of magnetic field intensity and magnetic field distribution of different schemes of permanent magnet array,it is determined that when the element of Halbach permanent magnet array is a fan and the array has two cycles,the processing area has the optimal magnetic field intensity and magnetic field distribution.(4)A series of single factor experiments were carried out on 30 CrMnSi high strength structural steel.The machining performance of 30 CrMnSi high strength structural steel plate was proved by the new magnetic field generator.The effects of different process parameters,such as the types of abrasive tools,the types of abrasive grains,the magnetic pole speed,the number of abrasive grains,the mass ratio between ferromagnetic phase and abrasive phase(two-phase mass ratio),and the processing clearance on the surface roughness were discussed.(5)Taguchi orthogonal experiment with 3 factor 3 level was designed with the magnetic pole rotation speed,the number of grinding grains and the mass ratio of two phases as experimental variables.Surface roughness Ra and material removal rate in ?m as output characteristic index,has carried on the finishing machining experiment of 30 CrMnSi structure steel.By means of grey correlation analysis and principal component analysis,the prediction model of GRG of grey correlation degree among output characteristic indexes on magnetic pole speed,number of abrasive grains and two-phase mass ratio was established,and the multi-objective optimization of magnetic abrasive finishing parameters of 30 CrMnSi structural steel plate was realized.The optimization results show that when the magnetic pole rotation speed is 500r/min,the number of abrasive grains is 240 mesh and the two-phase mass ratio is 2.5257:1,the maximum grey relational degree value is 0.7796.Verification tests showed that the optimized surface roughness Ra value dropped by 13.16% than before optimization,material removal amount ?m increased by 10.00%. |
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