| As a typical solid lubricating material,graphite material shows its excellent selflubricating properties and outstanding wear resistance.It is widely used in applications where lubricating oil or grease are not suitable,and occupies a very important position in the field of mechanical seals.There are many studies on the preparation technology and performance of graphite materials,and rich results have been achieved.However,the research and understanding of the lubrication rules of graphite materials during friction are insufficient.And a lot of experiments are accumulated in engineering practice to accumulate experience and lack of scientific guidance.In this paper,different types of graphite materials are used as research objects,and their mechanical properties and microstructures are determined through experiments.Combining experimental research and numerical research,friction,lubrication and lubrication processes of materials,speed,load,temperature,and grinding pair materials are explored.The influence law of refining the lubrication law of graphite materials under harsh working conditions provides the theoretical basis and scientific guidance for material preparation and sealing structure assembly.First,the microstructure composition of the material was obtained from a twodimensional perspective through metallographic and scanning electron microscope experiments,and the distribution and connection mode of the macerate and the carbon matrix were analyzed.The spatial morphology and distribution of macerate and carbon matrix were obtained by atomic force microscopy(AFM).Secondly,through the friction and wear experiment,the wear performance of three typical materials impregnated with antimony graphite,pure graphite and resin impregnated graphite under different working conditions of different speeds,different loads,different pairs of grinding pairs and different environmental temperatures was studied.Using single factor and orthogonal analysis methods,the optimal factors and main factors that affect the film formation of the lubricating film are analyzed,and the lubricating law is initially revealed.Then,through ABAQUS numerical simulation,the stress distribution characteristics of the contact surface under different working conditions were studied to further improve the lubrication rule of graphite materials.Finally,the simulation of the application of graphite materials in the rotary seal structure of the coal mill was carried out to estimate its wear and predict its wear resistance.The results show that:(1)The pure graphite material exhibits reverse film formation and ineffective lubrication;the resin-impregnated graphite material mostly exhibits oscillating film formation and hysteretic lubrication residual film;Antimonyimpregnated graphite materials mostly exhibit rapid film formation and stable lubrication film formation.(2)Through a single factor and orthogonal analysis,we can see that the antimony impregnated graphite exhibits the best performance under the conditions of large load(600 N),high speed(500 r/min)and hard alloy as the grinding pair Good lubrication performance.(3)The simulation results of different working conditions show that the temperature distribution and contact stress distribution of the pin model are not affected by the high speed and high load working conditions,and only have a numerical difference;at 0 ?,25 ?,50 ? temperature The simulation results below show that the antimony impregnated graphite material exhibits the best wear performance at an temperature of 25 ?.(4)The simulation of actual working conditions shows that under the condition of rated speed of 30 r/min and load of 50 N,the wear height of the seal ring in one year is only 5.86 mm,and the wear resistance is excellent. |
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