Research On Application Technology Of M50NIL Steel For Aviation~*-Engine Spindle Bearing

The main operating conditions of aeroengine spindle bearings are high temperature high load and high speed.Bearing ring will produce the circumferential tensile stress under the action of the circumferential stress produced by the fitting and the high centrifugal force produced by the ring and the rolling body under the high speed rotation.It is easy to cause the surface fatigue when the circumferential tensile stress of the working surface is too large,therefore the bearing rings with poor toughness materials will appear fatigue fracture.At the same time,with the development of aeroengine bearing,the bearing structure has changed from standardization to integration of elastically supported bearing,and it requires high deformation and extension ability of materials.According to the above situation,the aeroengine spindle bearing material gradually replaced M50 steel by M50 NiL steel after fourth-generation fighter jets.Although M50 NiL steel has better ductility fatigue resistance,there are many wear problems of guide surface in the model application.It indicates that there are still very large weaknesses in the mature application of this material.Therefore,it is necessary to study the basic properties,non wear resistance and surface modification of M50 NiL steel.By making up for the material defects,mastering and further excavating the material properties,the M50 NiL steel can be used in aeroengine bearings as soon as possible.This mainly focuses on the following three aspects.Through a comprehensive analysis of the physical and chemical properties of the M50 NiL steel material and a comparison of the overall performance of the M50 steel,the advantages and disadvantages of the M50 NiL steel are found through the application of the two kinds of bearings.The advantages are characterized by long life,complex structure,high temperature resistance and high dn value.The disadvantage is that the material carries a risk of surface wear as a guide surface.In view of the shortcomings of the easy wear of the guide surface of the M50 NiL steel,the reason why the material is not wearable is analyzed from the mechanism,analysis are carried out from the aspects of internal structure design,surface coating,and surface strengthening.The solution measures are formulated in combination with the access to the relevant foreign data.The effectiveness of the measure is confirmed by the preliminary test,surface can be coated with TiN film to avoid wear.Through the study of the nitriding technology,the optimal preparation process route is determined,and the sample processing is completed.The advantages anddisadvantages of the secondary hardening technology of the domestic M50 NiL steel are verified by compared the hardness and stress gradients with foreign samples,and the performance of the M50 NiL steel is constantly improved.Finally,the goal of equivalent of the application indicators of the M50 NiL steel and foreign is achieved.