Study On The Friction And Wear Properties Of 6061 Alloy With Low-temperature Salt Bath Treatment

In order to solve the problem of low hardness and non-wear resistance of 6061 aluminum alloy applied to the sleeve of the printing machine,this topic mainly studies the surface modification,and prepares aluminum nitride films and rubs them on the surface through low-temperature salt bath treatment.The wear performance study aims to improve the hardness,wear resistance and corrosion resistance of the aluminum alloy by changing the experimental conditions to increase the amount of hard phase compounds generated in the aluminum alloy,and to better promote the application of aluminum alloy in textile machinery.This article takes 6061Al-Mg-Si aluminum alloy as the research object,carries out a series of experiments to determine the temperature range and time range of nitriding and oxidation,and the process flow.Nitriding temperature: 490 °C ~ 550 °C,nitriding time: 1 ~ 3h;oxidation temperature: 340 °C ~ 400 °C,oxidation time: 20 ~ 60 min.A set of four factors and three levels of orthogonal tests were designed with the hardness as an indicator and the nitriding temperature,nitriding time,oxidation temperature,and oxidation time as four factors within the range of process parameters.Finally,the optimum analytical parameters obtained were: nitrogen The temperature of 520°C,nitriding time 3h,oxidation temperature of 400°C,oxidation time of 20 min,and the hardness of the sample after the optimal process parameters were 456.2HV,which was about 4 times that of the untreated substrate(116HV).The untreated sample,salt bath nitriding treatment and subsequent oxidation treatment of the sample were compared and analyzed.The sample was subjected to a series of tests such as XRD,EDS,SEM,and micro-hardness to characterize the test treatment effect and pass the friction wear.Experiments,corrosion resistance tests,etc.were used to investigate friction and wear properties and corrosion resistance before and after sample treatment.The results obtained are as follows:(1)In the SEM image of the permeation layer measured under the optimum process parameters,the sample can be seen to be divided into three distinct layers from top to bottom.The white bright layer on the surface is an oxide layer with a thickness of about 5 μm.The layer is mainly Al2O3,mainly formed in the preheating and oxidation steps;the middle part is a compound layer,the thickness is about 10-25 μm,and the compound layer is mainly AlN and Al4C3 phases,formed in the nitriding process;the resulting loose layer is The outer layer of the compound layer,the layer is loose,its hardness and wear resistance are relatively low;diffusion layer between the substrate and the compound,showing dark gray,thickness of about 10μm;(2)Friction and wear of composite treated,nitrided,and untreated samples under optimal conditions were investigated under different media conditions(dry friction,oillubrication),and SEM and white light interferometer were used.The surface morphology of the wear specimens was analyzed in 2D and 3D.The wear mechanisms were mainly abrasive wear and adhesive wear.The results show that low-temperature salt bath treatment can effectively reduce the specific wear rate of the sample,improve the wear resistance of the sample surface,the effect of the composite treatment is more obvious,when the load is 20 N,dry friction environment after nitriding treatment and composite treatment The specific wear rate of the sample decreased by 24% and 27%,respectively,compared with the untreated sample,and decreased by 50% and 56%,respectively,in the oil-lubricated environment.(3)Corrosion resistance test(neutral salt spray test,full immersion test,electrochemical corrosion)of samples subjected to composite treatment under the optimum process parameters,nitridized samples only,and untreated samples).The experimental results show that nitriding treatment and composite treatment can effectively reduce the corrosion weight loss of the sample,reduce the maximum corrosion pit depth,improve the corrosion resistance of the sample surface,the composite treatment effect is more obvious,nitrided sample and composite treatment sample The weight loss of corrosion was 35.27% and 46.23% lower than that of the untreated sample,respectively.