Syudy On Tangential Fretting Wear Behavior Of 2Cr13 Stainless Steel Treated By Laser Shock Peening

2Cr13 stainless steel is widely used in the manufacture of mechanical components such as steam turbine blades,hydraulic valves,fasteners,bearings because of its excellent comprehensive mechanical performance.However,the failure of mechanical components made of 2Cr13 stainless steel due to fretting damage is becoming increasingly prominent due to its poor wear resistance,temperature-sensitive mechanical properties,service environment and other complex factors.In order to solve the fretting wear failure problem of metal materials,various surface strengthening techniques are widely used.As a surface strengthening technology,laser shock peening can significantly improve the surface strength of metal materials,thereby effectively inhibiting fretting damage.Therefore,2Cr13 stainless steel was subjected to laser shock strengthening to study the influence of strengthening treatment on the microhardness and residual compressive stress of the sample surface,and the influence of displacement amplitude,normal load,temperature on the fretting wear characteristics of 2Cr13 stainless steel before and after laser shock strengthening.It is of great theoretical significance and engineering value for guiding the fretting damage protection design of 2Cr13 stainless steel.The main conclusions of this thesis are as follows:(1)With the increase of the displacement amplitude,the fretting regime of 2Cr13stainless steel gradually changes from the partial slip regime to the mix regime and the slip regime,and the friction coefficient shows a gradually increasing trend;With the increase of the normal load,the fretting regime gradually changes from the slip regime to the mix regime and the partial slip regime,and the friction coefficient shows a decreasing trend.The wear mechanism of the partial slip regime steel is mainly adhesive wear;the wear mechanism of the mix regime is mainly abrasive wear and delamination;the wear mechanism of the slip regime is mainly delamination and oxidation wear.With the increase of displacement amplitude,the wear amount of 2Cr13 stainless steel increases gradually;with the increase of normal load,the wear amount first increases and then decreases.As the fretting regime gradually changes from a partial slip regime to a slip regime,the oxidation reaction and material transfer between the friction pairs gradually intensify.(2)After laser shock peening,the surface hardness and residual compressive stress of 2Cr13 stainless steel increases significantly,but the fretting regime of 2Cr13 stainless steel doesn’t change after strengthening.When D=20μm,F_n=40 N,the friction coefficient decreases slightly.Delamination and abrasive wear are suppressed during the fretting wear test.At the same time,as the laser energy increased from 0 J to 11 J,the wear amount of2Cr13 stainless steel gradually decreases.(3)When D=20μm,F_n=40 N,and the temperature is 100℃,the fretting regime of2Cr13 stainless steel doesn’t change before and after laser shock peening;when the temperature is 200℃and 300℃,the fretting regime changes from the mix regime to slip regime.With the increase of temperature,the friction coefficient of 2Cr13 stainless steel before and after laser shock peening shows a trend of first increase and then decrease,and the wear amount shows a trend of first increase and then decrease.At room temperature,the main wear mechanism is delamination;when the temperature gradually increases,abrasive wear gradually dominates.When the temperature increases from 100℃to 200℃and 300℃,the degree of material damage gradually decreases,and the phenomenon of material transfer gradually weaken.