Study On Wear Resistance Of Ni Base Coating Reinforced By WC On Gear Steel Surface

As an important part of mechanical transmission system,gear has been widely used in various civil and military equipment.Usually,most of the mechanical transmission system will work in the heavy load,high temperature and impact and other bad service conditions,the key parts of the gear in the meshing is prone to wear failure,which affects the actual performance of the mechanical transmission system,which makes the whole machine has a big trouble hidden danger.If the tooth surface of the failed gear can be repaired and modified to improve the sustainable service life of the failed gear,it is of great significance to the development of China's remanufacturing engineering industry.Laser cladding technology has been widely used in repair of various parts due to its advantages such as unlimited material selection,concentrated energy,thick cladding thickness and good mechanical properties.Therefore,in this paper,the 20Cr2Ni4 A alloy steel carburized gear wear surface cladding coating is used to achieve the purpose of repair and modification,prolong the service life of the gear.It mainly includes the following work:(1)The process parameters(power,scanning speed,etc.)of coating preparation suitable for 20Cr2Ni4 A matrix material were obtained through trial and error method.The selection of appropriate cladding powder and the formulation of relevant cladding scheme ensure that the hardness,wear resistance and other mechanical properties of the surface of 20Cr2Ni4 A matrix material meet the industrial requirements,which lays a foundation for the subsequent cladding test of gear.(2)The use of advanced laser cladding technology in the 20Cr2Ni4 A alloy steel substrate materials on the surface of the preparation of the Ni60/WC and Ni65/WC composite coating,and based on the XRD,metallographic(OM)and scanning electron microscope(SEM),HV-1000 microhardness tester and MFT-5000 multifunctional friction and wear tester were used to characterize the phase composition,microstructure,microhardness and bonding force of the two composite coatings.The wear resistance of the two composite coatings was studied by HRS-2M tester,and the wear mechanism was explored.The hardness and wear resistance of Ni60/WC composite coating and Ni65/WC composite coating were evaluated by comparative experiments with carburized gear material.(3)According to the comparison between the diameters of the base circle and the root circle,the position of the working section of the tooth profile of the involute gear needed to be repaired was determined.In order to avoid the uneven impact of the energy absorbed by the gear material on the cladding quality,the tilt Angle of the gear was reduced as much as possible,and the relevant cladding process(first tooth groove,second tooth surface)was determined.The optimum tilt Angle values of the gear cladding the spot diameter parameters of the equipment,and uses the cladding equipment according to determine the related process will be the optimal performance of Ni65+20%WC cladding on the wear of tooth surface,from the point of actual effect,the surface is smooth level off,the roughness is good,no crack found,after the tooth body found no obvious deformation,the addendum place did not appear collapse phenomenon.