Study On Surface Strengthening Technology Of Disc Shear For Cold Rolling

The aim of this paper is to prolong the life of disc shear and improve product quality by investigating the surface strengthening technology of cold-rolled disc shear in order to.CrN coating was prepared by magnetron sputtering.It is studied how different process parameters influenced the surface strengthening of cold rolled disc shears The effect of different laser power on the wear resistance of cold rolled disc shear was researched by laser quenching process.CrN coating was prepared on 6542 high speed steel substrate by plasma enhanced balanced magnetron sputtering under different hot wire currents.The thickness,microstructure,chemical composition and hardness of the coatings were measured by contourgraph,SEM,XRD and microhardness tester.The effect of plasma enhanced on the balance was discussed.The structure and properties of titanium nitride coatings prepared by magnetron sputtering technology are discussed.The conclusions are listed as follow:(1)Under the same target current,but different filament currents,the surface structure of CrN thin films becomes denser and the particle size decreases gradually with the increase of current.On contrary,with increasing of current,the surface structure of CrN film becomes denser and the particle size decreases under the same filament current and different target current conditions.(2)The phase formed on the surface of the substrate is CrN.With the increase of filament current and target current,the intensity of the diffraction peak increases gradually.(3)The bonding strength and hardness of the film-base increase gradually with filament current and target current,and the friction coefficient of the sample surface decreases gradually.When filament current is 5A and the target current is 5A,the friction coefficient of the sample surface is 0.2296.(4)The matrix structure of cold-rolled disc shear mainly consists of acicular martensite.After laser quenching,acicular martensite structure disappears and dendrite network appears in hardened layer.The thickness of hardened layer increases with the laser power.After laser quenching with 3000 W,the thickness of hardened layer is 1333?m,and the number of dendrites in hardened layer tended to decrease.(5)The hardness of Cr12 MoV steel is 750 HV.With the increase of laser power,the hardness increases gradually.The hardness of Cr12 MoV steel reached the maximum after 3000 W laser quenching,e.i.,950 HV.(6)The friction coefficient of the matrix is 0.6376,and that of the sample quenched by 2000 W laser is 0.4294.With the increase of laser power,the friction coefficient decreases gradually.After 3000 W laser quenching,the friction coefficient droped the minimization,e.i.,0.3729.